drivers/scsi/st.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   4    file Documentation/scsi/st.rst for more information.
   5
   6    History:
   7    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   8    Contribution and ideas from several people including (in alphabetical
   9    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
  10    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  11    Michael Schaefer, J"org Weule, and Eric Youngdale.
  12
  13    Copyright 1992 - 2016 Kai Makisara
  14    email Kai.Makisara@kolumbus.fi
  15
  16    Some small formal changes - aeb, 950809
  17
  18    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  19  */
  20
  21 static const char *verstr = "20160209";
  22
  23 #include <linux/module.h>
  24
  25 #include <linux/compat.h>
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/mm.h>
  30 #include <linux/init.h>
  31 #include <linux/string.h>
  32 #include <linux/slab.h>
  33 #include <linux/errno.h>
  34 #include <linux/mtio.h>
  35 #include <linux/cdrom.h>
  36 #include <linux/ioctl.h>
  37 #include <linux/fcntl.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/blkdev.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/cdev.h>
  42 #include <linux/idr.h>
  43 #include <linux/delay.h>
  44 #include <linux/mutex.h>
  45
  46 #include <linux/uaccess.h>
  47 #include <asm/dma.h>
  48 #include <asm/unaligned.h>
  49
  50 #include <scsi/scsi.h>
  51 #include <scsi/scsi_dbg.h>
  52 #include <scsi/scsi_device.h>
  53 #include <scsi/scsi_driver.h>
  54 #include <scsi/scsi_eh.h>
  55 #include <scsi/scsi_host.h>
  56 #include <scsi/scsi_ioctl.h>
  57 #include <scsi/sg.h>
  58
  59
  60 /* The driver prints some debugging information on the console if DEBUG
  61    is defined and non-zero. */
  62 #define DEBUG 1
  63 #define NO_DEBUG 0
  64
  65 #define ST_DEB_MSG  KERN_NOTICE
  66 #if DEBUG
  67 /* The message level for the debug messages is currently set to KERN_NOTICE
  68    so that people can easily see the messages. Later when the debugging messages
  69    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  70 #define DEB(a) a
  71 #define DEBC(a) if (debugging) { a ; }
  72 #else
  73 #define DEB(a)
  74 #define DEBC(a)
  75 #endif
  76
  77 #define ST_KILOBYTE 1024
  78
  79 #include "st_options.h"
  80 #include "st.h"
  81
  82 static int buffer_kbs;
  83 static int max_sg_segs;
  84 static int try_direct_io = TRY_DIRECT_IO;
  85 static int try_rdio = 1;
  86 static int try_wdio = 1;
  87 static int debug_flag;
  88
  89 static struct class st_sysfs_class;
  90 static const struct attribute_group *st_dev_groups[];
  91 static const struct attribute_group *st_drv_groups[];
  92
  93 MODULE_AUTHOR("Kai Makisara");
  94 MODULE_DESCRIPTION("SCSI tape (st) driver");
  95 MODULE_LICENSE("GPL");
  96 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  97 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  98
  99 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
 100  * of sysfs parameters (which module_param doesn't yet support).
 101  * Sysfs parameters defined explicitly later.
 102  */
 103 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 104 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 105 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 106 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 107 module_param_named(try_direct_io, try_direct_io, int, 0);
 108 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 109 module_param_named(debug_flag, debug_flag, int, 0);
 110 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 111
 112
 113 /* Extra parameters for testing */
 114 module_param_named(try_rdio, try_rdio, int, 0);
 115 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 116 module_param_named(try_wdio, try_wdio, int, 0);
 117 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 118
 119 #ifndef MODULE
 120 static int write_threshold_kbs;  /* retained for compatibility */
 121 static struct st_dev_parm {
 122         char *name;
 123         int *val;
 124 } parms[] __initdata = {
 125         {
 126                 "buffer_kbs", &buffer_kbs
 127         },
 128         {       /* Retained for compatibility with 2.4 */
 129                 "write_threshold_kbs", &write_threshold_kbs
 130         },
 131         {
 132                 "max_sg_segs", NULL
 133         },
 134         {
 135                 "try_direct_io", &try_direct_io
 136         },
 137         {
 138                 "debug_flag", &debug_flag
 139         }
 140 };
 141 #endif
 142
 143 /* Restrict the number of modes so that names for all are assigned */
 144 #if ST_NBR_MODES > 16
 145 #error "Maximum number of modes is 16"
 146 #endif
 147 /* Bit reversed order to get same names for same minors with all
 148    mode counts */
 149 static const char *st_formats[] = {
 150         "",  "r", "k", "s", "l", "t", "o", "u",
 151         "m", "v", "p", "x", "a", "y", "q", "z"};
 152
 153 /* The default definitions have been moved to st_options.h */
 154
 155 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 156
 157 /* The buffer size should fit into the 24 bits for length in the
 158    6-byte SCSI read and write commands. */
 159 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 160 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 161 #endif
 162
 163 static int debugging = DEBUG;
 164
 165 #define MAX_RETRIES 0
 166 #define MAX_WRITE_RETRIES 0
 167 #define MAX_READY_RETRIES 0
 168 #define NO_TAPE  NOT_READY
 169
 170 #define ST_TIMEOUT (900 * HZ)
 171 #define ST_LONG_TIMEOUT (14000 * HZ)
 172
 173 /* Remove mode bits and auto-rewind bit (7) */
 174 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 175         (iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
 176 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 177
 178 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 179 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 180   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 181
 182 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 183    24 bits) */
 184 #define SET_DENS_AND_BLK 0x10001
 185
 186 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 187 static int st_max_sg_segs = ST_MAX_SG;
 188
 189 static int modes_defined;
 190
 191 static int enlarge_buffer(struct st_buffer *, int, int);
 192 static void clear_buffer(struct st_buffer *);
 193 static void normalize_buffer(struct st_buffer *);
 194 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 195 static int from_buffer(struct st_buffer *, char __user *, int);
 196 static void move_buffer_data(struct st_buffer *, int);
 197
 198 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 199                               unsigned long, size_t, int);
 200 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 201
 202 static int st_probe(struct device *);
 203 static int st_remove(struct device *);
 204
 205 static struct scsi_driver st_template = {
 206         .gendrv = {
 207                 .name           = "st",
 208                 .owner          = THIS_MODULE,
 209                 .probe          = st_probe,
 210                 .remove         = st_remove,
 211                 .groups         = st_drv_groups,
 212         },
 213 };
 214
 215 static int st_compression(struct scsi_tape *, int);
 216
 217 static int find_partition(struct scsi_tape *);
 218 static int switch_partition(struct scsi_tape *);
 219
 220 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 221
 222 static void scsi_tape_release(struct kref *);
 223
 224 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 225
 226 static DEFINE_MUTEX(st_ref_mutex);
 227 static DEFINE_SPINLOCK(st_index_lock);
 228 static DEFINE_SPINLOCK(st_use_lock);
 229 static DEFINE_IDR(st_index_idr);
 230
 231
 232 \f
 233 #ifndef SIGS_FROM_OSST
 234 #define SIGS_FROM_OSST \
 235         {"OnStream", "SC-", "", "osst"}, \
 236         {"OnStream", "DI-", "", "osst"}, \
 237         {"OnStream", "DP-", "", "osst"}, \
 238         {"OnStream", "USB", "", "osst"}, \
 239         {"OnStream", "FW-", "", "osst"}
 240 #endif
 241
 242 static struct scsi_tape *scsi_tape_get(int dev)
 243 {
 244         struct scsi_tape *STp = NULL;
 245
 246         mutex_lock(&st_ref_mutex);
 247         spin_lock(&st_index_lock);
 248
 249         STp = idr_find(&st_index_idr, dev);
 250         if (!STp) goto out;
 251
 252         kref_get(&STp->kref);
 253
 254         if (!STp->device)
 255                 goto out_put;
 256
 257         if (scsi_device_get(STp->device))
 258                 goto out_put;
 259
 260         goto out;
 261
 262 out_put:
 263         kref_put(&STp->kref, scsi_tape_release);
 264         STp = NULL;
 265 out:
 266         spin_unlock(&st_index_lock);
 267         mutex_unlock(&st_ref_mutex);
 268         return STp;
 269 }
 270
 271 static void scsi_tape_put(struct scsi_tape *STp)
 272 {
 273         struct scsi_device *sdev = STp->device;
 274
 275         mutex_lock(&st_ref_mutex);
 276         kref_put(&STp->kref, scsi_tape_release);
 277         scsi_device_put(sdev);
 278         mutex_unlock(&st_ref_mutex);
 279 }
 280
 281 struct st_reject_data {
 282         char *vendor;
 283         char *model;
 284         char *rev;
 285         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 286 };
 287
 288 static struct st_reject_data reject_list[] = {
 289         /* {"XXX", "Yy-", "", NULL},  example */
 290         SIGS_FROM_OSST,
 291         {NULL, }};
 292
 293 /* If the device signature is on the list of incompatible drives, the
 294    function returns a pointer to the name of the correct driver (if known) */
 295 static char * st_incompatible(struct scsi_device* SDp)
 296 {
 297         struct st_reject_data *rp;
 298
 299         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 300                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 301                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 302                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 303                         if (rp->driver_hint)
 304                                 return rp->driver_hint;
 305                         else
 306                                 return "unknown";
 307                 }
 308         return NULL;
 309 }
 310 \f
 311
 312 static inline char *tape_name(struct scsi_tape *tape)
 313 {
 314         return tape->disk->disk_name;
 315 }
 316
 317 #define st_printk(prefix, t, fmt, a...) \
 318         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 319 #ifdef DEBUG
 320 #define DEBC_printk(t, fmt, a...) \
 321         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 322 #else
 323 #define DEBC_printk(t, fmt, a...)
 324 #endif
 325
 326 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 327 {
 328         const u8 *ucp;
 329         const u8 *sense = SRpnt->sense;
 330
 331         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 332                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 333         s->flags = 0;
 334
 335         if (s->have_sense) {
 336                 s->deferred = 0;
 337                 s->remainder_valid =
 338                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 339                 switch (sense[0] & 0x7f) {
 340                 case 0x71:
 341                         s->deferred = 1;
 342                         /* fall through */
 343                 case 0x70:
 344                         s->fixed_format = 1;
 345                         s->flags = sense[2] & 0xe0;
 346                         break;
 347                 case 0x73:
 348                         s->deferred = 1;
 349                         /* fall through */
 350                 case 0x72:
 351                         s->fixed_format = 0;
 352                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 353                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 354                         break;
 355                 }
 356         }
 357 }
 358
 359
 360 /* Convert the result to success code */
 361 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 362 {
 363         int result = SRpnt->result;
 364         u8 scode;
 365         DEB(const char *stp;)
 366         char *name = tape_name(STp);
 367         struct st_cmdstatus *cmdstatp;
 368
 369         if (!result)
 370                 return 0;
 371
 372         cmdstatp = &STp->buffer->cmdstat;
 373         st_analyze_sense(SRpnt, cmdstatp);
 374
 375         if (cmdstatp->have_sense)
 376                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 377         else
 378                 scode = 0;
 379
 380         DEB(
 381         if (debugging) {
 382                 st_printk(ST_DEB_MSG, STp,
 383                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 384                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 385                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 386                 if (cmdstatp->have_sense)
 387                         __scsi_print_sense(STp->device, name,
 388                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 389         } ) /* end DEB */
 390         if (!debugging) { /* Abnormal conditions for tape */
 391                 if (!cmdstatp->have_sense)
 392                         st_printk(KERN_WARNING, STp,
 393                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 394                                result, driver_byte(result), host_byte(result));
 395                 else if (cmdstatp->have_sense &&
 396                          scode != NO_SENSE &&
 397                          scode != RECOVERED_ERROR &&
 398                          /* scode != UNIT_ATTENTION && */
 399                          scode != BLANK_CHECK &&
 400                          scode != VOLUME_OVERFLOW &&
 401                          SRpnt->cmd[0] != MODE_SENSE &&
 402                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 403
 404                         __scsi_print_sense(STp->device, name,
 405                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 406                 }
 407         }
 408
 409         if (cmdstatp->fixed_format &&
 410             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 411                 if (STp->cln_sense_value)
 412                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 413                                                STp->cln_sense_mask) == STp->cln_sense_value);
 414                 else
 415                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 416                                                STp->cln_sense_mask) != 0);
 417         }
 418         if (cmdstatp->have_sense &&
 419             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 420                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 421
 422         STp->pos_unknown |= STp->device->was_reset;
 423
 424         if (cmdstatp->have_sense &&
 425             scode == RECOVERED_ERROR
 426 #if ST_RECOVERED_WRITE_FATAL
 427             && SRpnt->cmd[0] != WRITE_6
 428             && SRpnt->cmd[0] != WRITE_FILEMARKS
 429 #endif
 430             ) {
 431                 STp->recover_count++;
 432                 STp->recover_reg++;
 433
 434                 DEB(
 435                 if (debugging) {
 436                         if (SRpnt->cmd[0] == READ_6)
 437                                 stp = "read";
 438                         else if (SRpnt->cmd[0] == WRITE_6)
 439                                 stp = "write";
 440                         else
 441                                 stp = "ioctl";
 442                         st_printk(ST_DEB_MSG, STp,
 443                                   "Recovered %s error (%d).\n",
 444                                   stp, STp->recover_count);
 445                 } ) /* end DEB */
 446
 447                 if (cmdstatp->flags == 0)
 448                         return 0;
 449         }
 450         return (-EIO);
 451 }
 452
 453 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 454 {
 455         struct st_request *streq;
 456
 457         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 458         if (streq)
 459                 streq->stp = stp;
 460         else {
 461                 st_printk(KERN_ERR, stp,
 462                           "Can't get SCSI request.\n");
 463                 if (signal_pending(current))
 464                         stp->buffer->syscall_result = -EINTR;
 465                 else
 466                         stp->buffer->syscall_result = -EBUSY;
 467         }
 468
 469         return streq;
 470 }
 471
 472 static void st_release_request(struct st_request *streq)
 473 {
 474         kfree(streq);
 475 }
 476
 477 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 478 {
 479         ktime_t now;
 480
 481         now = ktime_get();
 482         if (scsi_req(req)->cmd[0] == WRITE_6) {
 483                 now = ktime_sub(now, STp->stats->write_time);
 484                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 485                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 486                 atomic64_inc(&STp->stats->write_cnt);
 487                 if (scsi_req(req)->result) {
 488                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 489                                 - STp->buffer->cmdstat.residual,
 490                                 &STp->stats->write_byte_cnt);
 491                         if (STp->buffer->cmdstat.residual > 0)
 492                                 atomic64_inc(&STp->stats->resid_cnt);
 493                 } else
 494                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 495                                 &STp->stats->write_byte_cnt);
 496         } else if (scsi_req(req)->cmd[0] == READ_6) {
 497                 now = ktime_sub(now, STp->stats->read_time);
 498                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 499                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 500                 atomic64_inc(&STp->stats->read_cnt);
 501                 if (scsi_req(req)->result) {
 502                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 503                                 - STp->buffer->cmdstat.residual,
 504                                 &STp->stats->read_byte_cnt);
 505                         if (STp->buffer->cmdstat.residual > 0)
 506                                 atomic64_inc(&STp->stats->resid_cnt);
 507                 } else
 508                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 509                                 &STp->stats->read_byte_cnt);
 510         } else {
 511                 now = ktime_sub(now, STp->stats->other_time);
 512                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 513                 atomic64_inc(&STp->stats->other_cnt);
 514         }
 515         atomic64_dec(&STp->stats->in_flight);
 516 }
 517
 518 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 519 {
 520         struct st_request *SRpnt = req->end_io_data;
 521         struct scsi_request *rq = scsi_req(req);
 522         struct scsi_tape *STp = SRpnt->stp;
 523         struct bio *tmp;
 524
 525         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 526         STp->buffer->cmdstat.residual = rq->resid_len;
 527
 528         st_do_stats(STp, req);
 529
 530         tmp = SRpnt->bio;
 531         if (rq->sense_len)
 532                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 533         if (SRpnt->waiting)
 534                 complete(SRpnt->waiting);
 535
 536         blk_rq_unmap_user(tmp);
 537         blk_put_request(req);
 538 }
 539
 540 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 541                            int data_direction, void *buffer, unsigned bufflen,
 542                            int timeout, int retries)
 543 {
 544         struct request *req;
 545         struct scsi_request *rq;
 546         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 547         int err = 0;
 548         struct scsi_tape *STp = SRpnt->stp;
 549
 550         req = blk_get_request(SRpnt->stp->device->request_queue,
 551                         data_direction == DMA_TO_DEVICE ?
 552                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 553         if (IS_ERR(req))
 554                 return DRIVER_ERROR << 24;
 555         rq = scsi_req(req);
 556         req->rq_flags |= RQF_QUIET;
 557
 558         mdata->null_mapped = 1;
 559
 560         if (bufflen) {
 561                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 562                                       GFP_KERNEL);
 563                 if (err) {
 564                         blk_put_request(req);
 565                         return DRIVER_ERROR << 24;
 566                 }
 567         }
 568
 569         atomic64_inc(&STp->stats->in_flight);
 570         if (cmd[0] == WRITE_6) {
 571                 atomic_set(&STp->stats->last_write_size, bufflen);
 572                 STp->stats->write_time = ktime_get();
 573         } else if (cmd[0] == READ_6) {
 574                 atomic_set(&STp->stats->last_read_size, bufflen);
 575                 STp->stats->read_time = ktime_get();
 576         } else {
 577                 STp->stats->other_time = ktime_get();
 578         }
 579
 580         SRpnt->bio = req->bio;
 581         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 582         memset(rq->cmd, 0, BLK_MAX_CDB);
 583         memcpy(rq->cmd, cmd, rq->cmd_len);
 584         req->timeout = timeout;
 585         rq->retries = retries;
 586         req->end_io_data = SRpnt;
 587
 588         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 589         return 0;
 590 }
 591
 592 /* Do the scsi command. Waits until command performed if do_wait is true.
 593    Otherwise write_behind_check() is used to check that the command
 594    has finished. */
 595 static struct st_request *
 596 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 597            int bytes, int direction, int timeout, int retries, int do_wait)
 598 {
 599         struct completion *waiting;
 600         struct rq_map_data *mdata = &STp->buffer->map_data;
 601         int ret;
 602
 603         /* if async, make sure there's no command outstanding */
 604         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 605                 st_printk(KERN_ERR, STp,
 606                           "Async command already active.\n");
 607                 if (signal_pending(current))
 608                         (STp->buffer)->syscall_result = (-EINTR);
 609                 else
 610                         (STp->buffer)->syscall_result = (-EBUSY);
 611                 return NULL;
 612         }
 613
 614         if (!SRpnt) {
 615                 SRpnt = st_allocate_request(STp);
 616                 if (!SRpnt)
 617                         return NULL;
 618         }
 619
 620         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 621            which IO is outstanding. It's nulled out when the IO completes. */
 622         if (!do_wait)
 623                 (STp->buffer)->last_SRpnt = SRpnt;
 624
 625         waiting = &STp->wait;
 626         init_completion(waiting);
 627         SRpnt->waiting = waiting;
 628
 629         if (STp->buffer->do_dio) {
 630                 mdata->page_order = 0;
 631                 mdata->nr_entries = STp->buffer->sg_segs;
 632                 mdata->pages = STp->buffer->mapped_pages;
 633         } else {
 634                 mdata->page_order = STp->buffer->reserved_page_order;
 635                 mdata->nr_entries =
 636                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 637                 mdata->pages = STp->buffer->reserved_pages;
 638                 mdata->offset = 0;
 639         }
 640
 641         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 642         STp->buffer->cmdstat.have_sense = 0;
 643         STp->buffer->syscall_result = 0;
 644
 645         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 646                               retries);
 647         if (ret) {
 648                 /* could not allocate the buffer or request was too large */
 649                 (STp->buffer)->syscall_result = (-EBUSY);
 650                 (STp->buffer)->last_SRpnt = NULL;
 651         } else if (do_wait) {
 652                 wait_for_completion(waiting);
 653                 SRpnt->waiting = NULL;
 654                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 655         }
 656
 657         return SRpnt;
 658 }
 659
 660
 661 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 662    write has been correct but EOM early warning reached, -EIO if write ended in
 663    error or zero if write successful. Asynchronous writes are used only in
 664    variable block mode. */
 665 static int write_behind_check(struct scsi_tape * STp)
 666 {
 667         int retval = 0;
 668         struct st_buffer *STbuffer;
 669         struct st_partstat *STps;
 670         struct st_cmdstatus *cmdstatp;
 671         struct st_request *SRpnt;
 672
 673         STbuffer = STp->buffer;
 674         if (!STbuffer->writing)
 675                 return 0;
 676
 677         DEB(
 678         if (STp->write_pending)
 679                 STp->nbr_waits++;
 680         else
 681                 STp->nbr_finished++;
 682         ) /* end DEB */
 683
 684         wait_for_completion(&(STp->wait));
 685         SRpnt = STbuffer->last_SRpnt;
 686         STbuffer->last_SRpnt = NULL;
 687         SRpnt->waiting = NULL;
 688
 689         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 690         st_release_request(SRpnt);
 691
 692         STbuffer->buffer_bytes -= STbuffer->writing;
 693         STps = &(STp->ps[STp->partition]);
 694         if (STps->drv_block >= 0) {
 695                 if (STp->block_size == 0)
 696                         STps->drv_block++;
 697                 else
 698                         STps->drv_block += STbuffer->writing / STp->block_size;
 699         }
 700
 701         cmdstatp = &STbuffer->cmdstat;
 702         if (STbuffer->syscall_result) {
 703                 retval = -EIO;
 704                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 705                     (cmdstatp->flags & SENSE_EOM) &&
 706                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 707                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 708                         /* EOM at write-behind, has all data been written? */
 709                         if (!cmdstatp->remainder_valid ||
 710                             cmdstatp->uremainder64 == 0)
 711                                 retval = -ENOSPC;
 712                 }
 713                 if (retval == -EIO)
 714                         STps->drv_block = -1;
 715         }
 716         STbuffer->writing = 0;
 717
 718         DEB(if (debugging && retval)
 719                     st_printk(ST_DEB_MSG, STp,
 720                                 "Async write error %x, return value %d.\n",
 721                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 722
 723         return retval;
 724 }
 725
 726
 727 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 728    it messes up the block number). */
 729 static int cross_eof(struct scsi_tape * STp, int forward)
 730 {
 731         struct st_request *SRpnt;
 732         unsigned char cmd[MAX_COMMAND_SIZE];
 733
 734         cmd[0] = SPACE;
 735         cmd[1] = 0x01;          /* Space FileMarks */
 736         if (forward) {
 737                 cmd[2] = cmd[3] = 0;
 738                 cmd[4] = 1;
 739         } else
 740                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 741         cmd[5] = 0;
 742
 743         DEBC_printk(STp, "Stepping over filemark %s.\n",
 744                     forward ? "forward" : "backward");
 745
 746         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 747                            STp->device->request_queue->rq_timeout,
 748                            MAX_RETRIES, 1);
 749         if (!SRpnt)
 750                 return (STp->buffer)->syscall_result;
 751
 752         st_release_request(SRpnt);
 753         SRpnt = NULL;
 754
 755         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 756                 st_printk(KERN_ERR, STp,
 757                           "Stepping over filemark %s failed.\n",
 758                           forward ? "forward" : "backward");
 759
 760         return (STp->buffer)->syscall_result;
 761 }
 762
 763
 764 /* Flush the write buffer (never need to write if variable blocksize). */
 765 static int st_flush_write_buffer(struct scsi_tape * STp)
 766 {
 767         int transfer, blks;
 768         int result;
 769         unsigned char cmd[MAX_COMMAND_SIZE];
 770         struct st_request *SRpnt;
 771         struct st_partstat *STps;
 772
 773         result = write_behind_check(STp);
 774         if (result)
 775                 return result;
 776
 777         result = 0;
 778         if (STp->dirty == 1) {
 779
 780                 transfer = STp->buffer->buffer_bytes;
 781                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 782
 783                 memset(cmd, 0, MAX_COMMAND_SIZE);
 784                 cmd[0] = WRITE_6;
 785                 cmd[1] = 1;
 786                 blks = transfer / STp->block_size;
 787                 cmd[2] = blks >> 16;
 788                 cmd[3] = blks >> 8;
 789                 cmd[4] = blks;
 790
 791                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 792                                    STp->device->request_queue->rq_timeout,
 793                                    MAX_WRITE_RETRIES, 1);
 794                 if (!SRpnt)
 795                         return (STp->buffer)->syscall_result;
 796
 797                 STps = &(STp->ps[STp->partition]);
 798                 if ((STp->buffer)->syscall_result != 0) {
 799                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 800
 801                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 802                             (cmdstatp->flags & SENSE_EOM) &&
 803                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 804                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 805                             (!cmdstatp->remainder_valid ||
 806                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 807                                 STp->dirty = 0;
 808                                 (STp->buffer)->buffer_bytes = 0;
 809                                 if (STps->drv_block >= 0)
 810                                         STps->drv_block += blks;
 811                                 result = (-ENOSPC);
 812                         } else {
 813                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 814                                 STps->drv_block = (-1);
 815                                 result = (-EIO);
 816                         }
 817                 } else {
 818                         if (STps->drv_block >= 0)
 819                                 STps->drv_block += blks;
 820                         STp->dirty = 0;
 821                         (STp->buffer)->buffer_bytes = 0;
 822                 }
 823                 st_release_request(SRpnt);
 824                 SRpnt = NULL;
 825         }
 826         return result;
 827 }
 828
 829
 830 /* Flush the tape buffer. The tape will be positioned correctly unless
 831    seek_next is true. */
 832 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 833 {
 834         int backspace, result;
 835         struct st_partstat *STps;
 836
 837         /*
 838          * If there was a bus reset, block further access
 839          * to this device.
 840          */
 841         if (STp->pos_unknown)
 842                 return (-EIO);
 843
 844         if (STp->ready != ST_READY)
 845                 return 0;
 846         STps = &(STp->ps[STp->partition]);
 847         if (STps->rw == ST_WRITING)     /* Writing */
 848                 return st_flush_write_buffer(STp);
 849
 850         if (STp->block_size == 0)
 851                 return 0;
 852
 853         backspace = ((STp->buffer)->buffer_bytes +
 854                      (STp->buffer)->read_pointer) / STp->block_size -
 855             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 856             STp->block_size;
 857         (STp->buffer)->buffer_bytes = 0;
 858         (STp->buffer)->read_pointer = 0;
 859         result = 0;
 860         if (!seek_next) {
 861                 if (STps->eof == ST_FM_HIT) {
 862                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 863                         if (!result)
 864                                 STps->eof = ST_NOEOF;
 865                         else {
 866                                 if (STps->drv_file >= 0)
 867                                         STps->drv_file++;
 868                                 STps->drv_block = 0;
 869                         }
 870                 }
 871                 if (!result && backspace > 0)
 872                         result = st_int_ioctl(STp, MTBSR, backspace);
 873         } else if (STps->eof == ST_FM_HIT) {
 874                 if (STps->drv_file >= 0)
 875                         STps->drv_file++;
 876                 STps->drv_block = 0;
 877                 STps->eof = ST_NOEOF;
 878         }
 879         return result;
 880
 881 }
 882 \f
 883 /* Set the mode parameters */
 884 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 885 {
 886         int set_it = 0;
 887         unsigned long arg;
 888
 889         if (!STp->density_changed &&
 890             STm->default_density >= 0 &&
 891             STm->default_density != STp->density) {
 892                 arg = STm->default_density;
 893                 set_it = 1;
 894         } else
 895                 arg = STp->density;
 896         arg <<= MT_ST_DENSITY_SHIFT;
 897         if (!STp->blksize_changed &&
 898             STm->default_blksize >= 0 &&
 899             STm->default_blksize != STp->block_size) {
 900                 arg |= STm->default_blksize;
 901                 set_it = 1;
 902         } else
 903                 arg |= STp->block_size;
 904         if (set_it &&
 905             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 906                 st_printk(KERN_WARNING, STp,
 907                           "Can't set default block size to %d bytes "
 908                           "and density %x.\n",
 909                           STm->default_blksize, STm->default_density);
 910                 if (modes_defined)
 911                         return (-EINVAL);
 912         }
 913         return 0;
 914 }
 915
 916
 917 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 918 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 919 {
 920         int retval;
 921
 922         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 923
 924         retval = scsi_set_medium_removal(STp->device,
 925                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 926         if (!retval)
 927                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 928         else
 929                 STp->door_locked = ST_LOCK_FAILS;
 930         return retval;
 931 }
 932
 933
 934 /* Set the internal state after reset */
 935 static void reset_state(struct scsi_tape *STp)
 936 {
 937         int i;
 938         struct st_partstat *STps;
 939
 940         STp->pos_unknown = 0;
 941         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 942                 STps = &(STp->ps[i]);
 943                 STps->rw = ST_IDLE;
 944                 STps->eof = ST_NOEOF;
 945                 STps->at_sm = 0;
 946                 STps->last_block_valid = 0;
 947                 STps->drv_block = -1;
 948                 STps->drv_file = -1;
 949         }
 950         if (STp->can_partitions) {
 951                 STp->partition = find_partition(STp);
 952                 if (STp->partition < 0)
 953                         STp->partition = 0;
 954                 STp->new_partition = STp->partition;
 955         }
 956 }
 957 \f
 958 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 959    error code. */
 960 #define CHKRES_READY       0
 961 #define CHKRES_NEW_SESSION 1
 962 #define CHKRES_NOT_READY   2
 963 #define CHKRES_NO_TAPE     3
 964
 965 #define MAX_ATTENTIONS    10
 966
 967 static int test_ready(struct scsi_tape *STp, int do_wait)
 968 {
 969         int attentions, waits, max_wait, scode;
 970         int retval = CHKRES_READY, new_session = 0;
 971         unsigned char cmd[MAX_COMMAND_SIZE];
 972         struct st_request *SRpnt = NULL;
 973         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 974
 975         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 976
 977         for (attentions=waits=0; ; ) {
 978                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 979                 cmd[0] = TEST_UNIT_READY;
 980                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 981                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 982
 983                 if (!SRpnt) {
 984                         retval = (STp->buffer)->syscall_result;
 985                         break;
 986                 }
 987
 988                 if (cmdstatp->have_sense) {
 989
 990                         scode = cmdstatp->sense_hdr.sense_key;
 991
 992                         if (scode == UNIT_ATTENTION) { /* New media? */
 993                                 new_session = 1;
 994                                 if (attentions < MAX_ATTENTIONS) {
 995                                         attentions++;
 996                                         continue;
 997                                 }
 998                                 else {
 999                                         retval = (-EIO);
1000                                         break;
1001                                 }
1002                         }
1003
1004                         if (scode == NOT_READY) {
1005                                 if (waits < max_wait) {
1006                                         if (msleep_interruptible(1000)) {
1007                                                 retval = (-EINTR);
1008                                                 break;
1009                                         }
1010                                         waits++;
1011                                         continue;
1012                                 }
1013                                 else {
1014                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1015                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1016                                                 retval = CHKRES_NO_TAPE;
1017                                         else
1018                                                 retval = CHKRES_NOT_READY;
1019                                         break;
1020                                 }
1021                         }
1022                 }
1023
1024                 retval = (STp->buffer)->syscall_result;
1025                 if (!retval)
1026                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1027                 break;
1028         }
1029
1030         if (SRpnt != NULL)
1031                 st_release_request(SRpnt);
1032         return retval;
1033 }
1034
1035
1036 /* See if the drive is ready and gather information about the tape. Return values:
1037    < 0   negative error code from errno.h
1038    0     drive ready
1039    1     drive not ready (possibly no tape)
1040 */
1041 static int check_tape(struct scsi_tape *STp, struct file *filp)
1042 {
1043         int i, retval, new_session = 0, do_wait;
1044         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1045         unsigned short st_flags = filp->f_flags;
1046         struct st_request *SRpnt = NULL;
1047         struct st_modedef *STm;
1048         struct st_partstat *STps;
1049         struct inode *inode = file_inode(filp);
1050         int mode = TAPE_MODE(inode);
1051
1052         STp->ready = ST_READY;
1053
1054         if (mode != STp->current_mode) {
1055                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1056                             STp->current_mode, mode);
1057                 new_session = 1;
1058                 STp->current_mode = mode;
1059         }
1060         STm = &(STp->modes[STp->current_mode]);
1061
1062         saved_cleaning = STp->cleaning_req;
1063         STp->cleaning_req = 0;
1064
1065         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1066         retval = test_ready(STp, do_wait);
1067
1068         if (retval < 0)
1069             goto err_out;
1070
1071         if (retval == CHKRES_NEW_SESSION) {
1072                 STp->pos_unknown = 0;
1073                 STp->partition = STp->new_partition = 0;
1074                 if (STp->can_partitions)
1075                         STp->nbr_partitions = 1; /* This guess will be updated later
1076                                                     if necessary */
1077                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1078                         STps = &(STp->ps[i]);
1079                         STps->rw = ST_IDLE;
1080                         STps->eof = ST_NOEOF;
1081                         STps->at_sm = 0;
1082                         STps->last_block_valid = 0;
1083                         STps->drv_block = 0;
1084                         STps->drv_file = 0;
1085                 }
1086                 new_session = 1;
1087         }
1088         else {
1089                 STp->cleaning_req |= saved_cleaning;
1090
1091                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1092                         if (retval == CHKRES_NO_TAPE)
1093                                 STp->ready = ST_NO_TAPE;
1094                         else
1095                                 STp->ready = ST_NOT_READY;
1096
1097                         STp->density = 0;       /* Clear the erroneous "residue" */
1098                         STp->write_prot = 0;
1099                         STp->block_size = 0;
1100                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1101                         STp->partition = STp->new_partition = 0;
1102                         STp->door_locked = ST_UNLOCKED;
1103                         return CHKRES_NOT_READY;
1104                 }
1105         }
1106
1107         if (STp->omit_blklims)
1108                 STp->min_block = STp->max_block = (-1);
1109         else {
1110                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1111                 cmd[0] = READ_BLOCK_LIMITS;
1112
1113                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1114                                    STp->device->request_queue->rq_timeout,
1115                                    MAX_READY_RETRIES, 1);
1116                 if (!SRpnt) {
1117                         retval = (STp->buffer)->syscall_result;
1118                         goto err_out;
1119                 }
1120
1121                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1122                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1123                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1124                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1125                             (STp->buffer)->b_data[5];
1126                         if ( DEB( debugging || ) !STp->inited)
1127                                 st_printk(KERN_INFO, STp,
1128                                           "Block limits %d - %d bytes.\n",
1129                                           STp->min_block, STp->max_block);
1130                 } else {
1131                         STp->min_block = STp->max_block = (-1);
1132                         DEBC_printk(STp, "Can't read block limits.\n");
1133                 }
1134         }
1135
1136         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1137         cmd[0] = MODE_SENSE;
1138         cmd[4] = 12;
1139
1140         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1141                            STp->device->request_queue->rq_timeout,
1142                            MAX_READY_RETRIES, 1);
1143         if (!SRpnt) {
1144                 retval = (STp->buffer)->syscall_result;
1145                 goto err_out;
1146         }
1147
1148         if ((STp->buffer)->syscall_result != 0) {
1149                 DEBC_printk(STp, "No Mode Sense.\n");
1150                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1151                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1152                 STp->drv_write_prot = 0;
1153         } else {
1154                 DEBC_printk(STp,"Mode sense. Length %d, "
1155                             "medium %x, WBS %x, BLL %d\n",
1156                             (STp->buffer)->b_data[0],
1157                             (STp->buffer)->b_data[1],
1158                             (STp->buffer)->b_data[2],
1159                             (STp->buffer)->b_data[3]);
1160
1161                 if ((STp->buffer)->b_data[3] >= 8) {
1162                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1163                         STp->density = (STp->buffer)->b_data[4];
1164                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1165                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1166                         DEBC_printk(STp, "Density %x, tape length: %x, "
1167                                     "drv buffer: %d\n",
1168                                     STp->density,
1169                                     (STp->buffer)->b_data[5] * 65536 +
1170                                     (STp->buffer)->b_data[6] * 256 +
1171                                     (STp->buffer)->b_data[7],
1172                                     STp->drv_buffer);
1173                 }
1174                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1175                 if (!STp->drv_buffer && STp->immediate_filemark) {
1176                         st_printk(KERN_WARNING, STp,
1177                                   "non-buffered tape: disabling "
1178                                   "writing immediate filemarks\n");
1179                         STp->immediate_filemark = 0;
1180                 }
1181         }
1182         st_release_request(SRpnt);
1183         SRpnt = NULL;
1184         STp->inited = 1;
1185
1186         if (STp->block_size > 0)
1187                 (STp->buffer)->buffer_blocks =
1188                         (STp->buffer)->buffer_size / STp->block_size;
1189         else
1190                 (STp->buffer)->buffer_blocks = 1;
1191         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1192
1193         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1194                     STp->block_size, (STp->buffer)->buffer_size,
1195                     (STp->buffer)->buffer_blocks);
1196
1197         if (STp->drv_write_prot) {
1198                 STp->write_prot = 1;
1199
1200                 DEBC_printk(STp, "Write protected\n");
1201
1202                 if (do_wait &&
1203                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1204                      (st_flags & O_ACCMODE) == O_RDWR)) {
1205                         retval = (-EROFS);
1206                         goto err_out;
1207                 }
1208         }
1209
1210         if (STp->can_partitions && STp->nbr_partitions < 1) {
1211                 /* This code is reached when the device is opened for the first time
1212                    after the driver has been initialized with tape in the drive and the
1213                    partition support has been enabled. */
1214                 DEBC_printk(STp, "Updating partition number in status.\n");
1215                 if ((STp->partition = find_partition(STp)) < 0) {
1216                         retval = STp->partition;
1217                         goto err_out;
1218                 }
1219                 STp->new_partition = STp->partition;
1220                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1221         }
1222
1223         if (new_session) {      /* Change the drive parameters for the new mode */
1224                 STp->density_changed = STp->blksize_changed = 0;
1225                 STp->compression_changed = 0;
1226                 if (!(STm->defaults_for_writes) &&
1227                     (retval = set_mode_densblk(STp, STm)) < 0)
1228                     goto err_out;
1229
1230                 if (STp->default_drvbuffer != 0xff) {
1231                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1232                                 st_printk(KERN_WARNING, STp,
1233                                           "Can't set default drive "
1234                                           "buffering to %d.\n",
1235                                           STp->default_drvbuffer);
1236                 }
1237         }
1238
1239         return CHKRES_READY;
1240
1241  err_out:
1242         return retval;
1243 }
1244
1245
1246 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1247    module count. */
1248 static int st_open(struct inode *inode, struct file *filp)
1249 {
1250         int i, retval = (-EIO);
1251         int resumed = 0;
1252         struct scsi_tape *STp;
1253         struct st_partstat *STps;
1254         int dev = TAPE_NR(inode);
1255
1256         /*
1257          * We really want to do nonseekable_open(inode, filp); here, but some
1258          * versions of tar incorrectly call lseek on tapes and bail out if that
1259          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1260          */
1261         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1262
1263         if (!(STp = scsi_tape_get(dev))) {
1264                 return -ENXIO;
1265         }
1266
1267         filp->private_data = STp;
1268
1269         spin_lock(&st_use_lock);
1270         if (STp->in_use) {
1271                 spin_unlock(&st_use_lock);
1272                 scsi_tape_put(STp);
1273                 DEBC_printk(STp, "Device already in use.\n");
1274                 return (-EBUSY);
1275         }
1276
1277         STp->in_use = 1;
1278         spin_unlock(&st_use_lock);
1279         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1280
1281         if (scsi_autopm_get_device(STp->device) < 0) {
1282                 retval = -EIO;
1283                 goto err_out;
1284         }
1285         resumed = 1;
1286         if (!scsi_block_when_processing_errors(STp->device)) {
1287                 retval = (-ENXIO);
1288                 goto err_out;
1289         }
1290
1291         /* See that we have at least a one page buffer available */
1292         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1293                 st_printk(KERN_WARNING, STp,
1294                           "Can't allocate one page tape buffer.\n");
1295                 retval = (-EOVERFLOW);
1296                 goto err_out;
1297         }
1298
1299         (STp->buffer)->cleared = 0;
1300         (STp->buffer)->writing = 0;
1301         (STp->buffer)->syscall_result = 0;
1302
1303         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1304
1305         STp->dirty = 0;
1306         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1307                 STps = &(STp->ps[i]);
1308                 STps->rw = ST_IDLE;
1309         }
1310         STp->try_dio_now = STp->try_dio;
1311         STp->recover_count = 0;
1312         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1313              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1314
1315         retval = check_tape(STp, filp);
1316         if (retval < 0)
1317                 goto err_out;
1318         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1319             retval != CHKRES_READY) {
1320                 if (STp->ready == NO_TAPE)
1321                         retval = (-ENOMEDIUM);
1322                 else
1323                         retval = (-EIO);
1324                 goto err_out;
1325         }
1326         return 0;
1327
1328  err_out:
1329         normalize_buffer(STp->buffer);
1330         spin_lock(&st_use_lock);
1331         STp->in_use = 0;
1332         spin_unlock(&st_use_lock);
1333         if (resumed)
1334                 scsi_autopm_put_device(STp->device);
1335         scsi_tape_put(STp);
1336         return retval;
1337
1338 }
1339 \f
1340
1341 /* Flush the tape buffer before close */
1342 static int st_flush(struct file *filp, fl_owner_t id)
1343 {
1344         int result = 0, result2;
1345         unsigned char cmd[MAX_COMMAND_SIZE];
1346         struct st_request *SRpnt;
1347         struct scsi_tape *STp = filp->private_data;
1348         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1349         struct st_partstat *STps = &(STp->ps[STp->partition]);
1350
1351         if (file_count(filp) > 1)
1352                 return 0;
1353
1354         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1355                 result = st_flush_write_buffer(STp);
1356                 if (result != 0 && result != (-ENOSPC))
1357                         goto out;
1358         }
1359
1360         if (STp->can_partitions &&
1361             (result2 = switch_partition(STp)) < 0) {
1362                 DEBC_printk(STp, "switch_partition at close failed.\n");
1363                 if (result == 0)
1364                         result = result2;
1365                 goto out;
1366         }
1367
1368         DEBC( if (STp->nbr_requests)
1369                 st_printk(KERN_DEBUG, STp,
1370                           "Number of r/w requests %d, dio used in %d, "
1371                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1372                           STp->nbr_pages));
1373
1374         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1375                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1376
1377 #if DEBUG
1378                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1379                             STp->nbr_waits, STp->nbr_finished);
1380 #endif
1381                 memset(cmd, 0, MAX_COMMAND_SIZE);
1382                 cmd[0] = WRITE_FILEMARKS;
1383                 if (STp->immediate_filemark)
1384                         cmd[1] = 1;
1385                 cmd[4] = 1 + STp->two_fm;
1386
1387                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1388                                    STp->device->request_queue->rq_timeout,
1389                                    MAX_WRITE_RETRIES, 1);
1390                 if (!SRpnt) {
1391                         result = (STp->buffer)->syscall_result;
1392                         goto out;
1393                 }
1394
1395                 if (STp->buffer->syscall_result == 0 ||
1396                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1397                      (cmdstatp->flags & SENSE_EOM) &&
1398                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1399                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1400                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1401                         /* Write successful at EOM */
1402                         st_release_request(SRpnt);
1403                         SRpnt = NULL;
1404                         if (STps->drv_file >= 0)
1405                                 STps->drv_file++;
1406                         STps->drv_block = 0;
1407                         if (STp->two_fm)
1408                                 cross_eof(STp, 0);
1409                         STps->eof = ST_FM;
1410                 }
1411                 else { /* Write error */
1412                         st_release_request(SRpnt);
1413                         SRpnt = NULL;
1414                         st_printk(KERN_ERR, STp,
1415                                   "Error on write filemark.\n");
1416                         if (result == 0)
1417                                 result = (-EIO);
1418                 }
1419
1420                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1421         } else if (!STp->rew_at_close) {
1422                 STps = &(STp->ps[STp->partition]);
1423                 if (!STm->sysv || STps->rw != ST_READING) {
1424                         if (STp->can_bsr)
1425                                 result = flush_buffer(STp, 0);
1426                         else if (STps->eof == ST_FM_HIT) {
1427                                 result = cross_eof(STp, 0);
1428                                 if (result) {
1429                                         if (STps->drv_file >= 0)
1430                                                 STps->drv_file++;
1431                                         STps->drv_block = 0;
1432                                         STps->eof = ST_FM;
1433                                 } else
1434                                         STps->eof = ST_NOEOF;
1435                         }
1436                 } else if ((STps->eof == ST_NOEOF &&
1437                             !(result = cross_eof(STp, 1))) ||
1438                            STps->eof == ST_FM_HIT) {
1439                         if (STps->drv_file >= 0)
1440                                 STps->drv_file++;
1441                         STps->drv_block = 0;
1442                         STps->eof = ST_FM;
1443                 }
1444         }
1445
1446       out:
1447         if (STp->rew_at_close) {
1448                 result2 = st_int_ioctl(STp, MTREW, 1);
1449                 if (result == 0)
1450                         result = result2;
1451         }
1452         return result;
1453 }
1454
1455
1456 /* Close the device and release it. BKL is not needed: this is the only thread
1457    accessing this tape. */
1458 static int st_release(struct inode *inode, struct file *filp)
1459 {
1460         int result = 0;
1461         struct scsi_tape *STp = filp->private_data;
1462
1463         if (STp->door_locked == ST_LOCKED_AUTO)
1464                 do_door_lock(STp, 0);
1465
1466         normalize_buffer(STp->buffer);
1467         spin_lock(&st_use_lock);
1468         STp->in_use = 0;
1469         spin_unlock(&st_use_lock);
1470         scsi_autopm_put_device(STp->device);
1471         scsi_tape_put(STp);
1472
1473         return result;
1474 }
1475 \f
1476 /* The checks common to both reading and writing */
1477 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1478 {
1479         ssize_t retval = 0;
1480
1481         /*
1482          * If we are in the middle of error recovery, don't let anyone
1483          * else try and use this device.  Also, if error recovery fails, it
1484          * may try and take the device offline, in which case all further
1485          * access to the device is prohibited.
1486          */
1487         if (!scsi_block_when_processing_errors(STp->device)) {
1488                 retval = (-ENXIO);
1489                 goto out;
1490         }
1491
1492         if (STp->ready != ST_READY) {
1493                 if (STp->ready == ST_NO_TAPE)
1494                         retval = (-ENOMEDIUM);
1495                 else
1496                         retval = (-EIO);
1497                 goto out;
1498         }
1499
1500         if (! STp->modes[STp->current_mode].defined) {
1501                 retval = (-ENXIO);
1502                 goto out;
1503         }
1504
1505
1506         /*
1507          * If there was a bus reset, block further access
1508          * to this device.
1509          */
1510         if (STp->pos_unknown) {
1511                 retval = (-EIO);
1512                 goto out;
1513         }
1514
1515         if (count == 0)
1516                 goto out;
1517
1518         DEB(
1519         if (!STp->in_use) {
1520                 st_printk(ST_DEB_MSG, STp,
1521                           "Incorrect device.\n");
1522                 retval = (-EIO);
1523                 goto out;
1524         } ) /* end DEB */
1525
1526         if (STp->can_partitions &&
1527             (retval = switch_partition(STp)) < 0)
1528                 goto out;
1529
1530         if (STp->block_size == 0 && STp->max_block > 0 &&
1531             (count < STp->min_block || count > STp->max_block)) {
1532                 retval = (-EINVAL);
1533                 goto out;
1534         }
1535
1536         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1537             !do_door_lock(STp, 1))
1538                 STp->door_locked = ST_LOCKED_AUTO;
1539
1540  out:
1541         return retval;
1542 }
1543
1544
1545 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1546                            size_t count, int is_read)
1547 {
1548         int i, bufsize, retval = 0;
1549         struct st_buffer *STbp = STp->buffer;
1550
1551         if (is_read)
1552                 i = STp->try_dio_now && try_rdio;
1553         else
1554                 i = STp->try_dio_now && try_wdio;
1555
1556         if (i && ((unsigned long)buf & queue_dma_alignment(
1557                                         STp->device->request_queue)) == 0) {
1558                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1559                                        count, (is_read ? READ : WRITE));
1560                 if (i > 0) {
1561                         STbp->do_dio = i;
1562                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1563                 }
1564                 else
1565                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1566                 STbp->sg_segs = STbp->do_dio;
1567                 DEB(
1568                      if (STbp->do_dio) {
1569                         STp->nbr_dio++;
1570                         STp->nbr_pages += STbp->do_dio;
1571                      }
1572                 )
1573         } else
1574                 STbp->do_dio = 0;
1575         DEB( STp->nbr_requests++; )
1576
1577         if (!STbp->do_dio) {
1578                 if (STp->block_size)
1579                         bufsize = STp->block_size > st_fixed_buffer_size ?
1580                                 STp->block_size : st_fixed_buffer_size;
1581                 else {
1582                         bufsize = count;
1583                         /* Make sure that data from previous user is not leaked even if
1584                            HBA does not return correct residual */
1585                         if (is_read && STp->sili && !STbp->cleared)
1586                                 clear_buffer(STbp);
1587                 }
1588
1589                 if (bufsize > STbp->buffer_size &&
1590                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1591                         st_printk(KERN_WARNING, STp,
1592                                   "Can't allocate %d byte tape buffer.\n",
1593                                   bufsize);
1594                         retval = (-EOVERFLOW);
1595                         goto out;
1596                 }
1597                 if (STp->block_size)
1598                         STbp->buffer_blocks = bufsize / STp->block_size;
1599         }
1600
1601  out:
1602         return retval;
1603 }
1604
1605
1606 /* Can be called more than once after each setup_buffer() */
1607 static void release_buffering(struct scsi_tape *STp, int is_read)
1608 {
1609         struct st_buffer *STbp;
1610
1611         STbp = STp->buffer;
1612         if (STbp->do_dio) {
1613                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1614                 STbp->do_dio = 0;
1615                 STbp->sg_segs = 0;
1616         }
1617 }
1618
1619
1620 /* Write command */
1621 static ssize_t
1622 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1623 {
1624         ssize_t total;
1625         ssize_t i, do_count, blks, transfer;
1626         ssize_t retval;
1627         int undone, retry_eot = 0, scode;
1628         int async_write;
1629         unsigned char cmd[MAX_COMMAND_SIZE];
1630         const char __user *b_point;
1631         struct st_request *SRpnt = NULL;
1632         struct scsi_tape *STp = filp->private_data;
1633         struct st_modedef *STm;
1634         struct st_partstat *STps;
1635         struct st_buffer *STbp;
1636
1637         if (mutex_lock_interruptible(&STp->lock))
1638                 return -ERESTARTSYS;
1639
1640         retval = rw_checks(STp, filp, count);
1641         if (retval || count == 0)
1642                 goto out;
1643
1644         /* Write must be integral number of blocks */
1645         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1646                 st_printk(KERN_WARNING, STp,
1647                           "Write not multiple of tape block size.\n");
1648                 retval = (-EINVAL);
1649                 goto out;
1650         }
1651
1652         STm = &(STp->modes[STp->current_mode]);
1653         STps = &(STp->ps[STp->partition]);
1654
1655         if (STp->write_prot) {
1656                 retval = (-EACCES);
1657                 goto out;
1658         }
1659
1660
1661         if (STps->rw == ST_READING) {
1662                 retval = flush_buffer(STp, 0);
1663                 if (retval)
1664                         goto out;
1665                 STps->rw = ST_WRITING;
1666         } else if (STps->rw != ST_WRITING &&
1667                    STps->drv_file == 0 && STps->drv_block == 0) {
1668                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1669                         goto out;
1670                 if (STm->default_compression != ST_DONT_TOUCH &&
1671                     !(STp->compression_changed)) {
1672                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1673                                 st_printk(KERN_WARNING, STp,
1674                                           "Can't set default compression.\n");
1675                                 if (modes_defined) {
1676                                         retval = (-EINVAL);
1677                                         goto out;
1678                                 }
1679                         }
1680                 }
1681         }
1682
1683         STbp = STp->buffer;
1684         i = write_behind_check(STp);
1685         if (i) {
1686                 if (i == -ENOSPC)
1687                         STps->eof = ST_EOM_OK;
1688                 else
1689                         STps->eof = ST_EOM_ERROR;
1690         }
1691
1692         if (STps->eof == ST_EOM_OK) {
1693                 STps->eof = ST_EOD_1;  /* allow next write */
1694                 retval = (-ENOSPC);
1695                 goto out;
1696         }
1697         else if (STps->eof == ST_EOM_ERROR) {
1698                 retval = (-EIO);
1699                 goto out;
1700         }
1701
1702         /* Check the buffer readability in cases where copy_user might catch
1703            the problems after some tape movement. */
1704         if (STp->block_size != 0 &&
1705             !STbp->do_dio &&
1706             (copy_from_user(&i, buf, 1) != 0 ||
1707              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1708                 retval = (-EFAULT);
1709                 goto out;
1710         }
1711
1712         retval = setup_buffering(STp, buf, count, 0);
1713         if (retval)
1714                 goto out;
1715
1716         total = count;
1717
1718         memset(cmd, 0, MAX_COMMAND_SIZE);
1719         cmd[0] = WRITE_6;
1720         cmd[1] = (STp->block_size != 0);
1721
1722         STps->rw = ST_WRITING;
1723
1724         b_point = buf;
1725         while (count > 0 && !retry_eot) {
1726
1727                 if (STbp->do_dio) {
1728                         do_count = count;
1729                 }
1730                 else {
1731                         if (STp->block_size == 0)
1732                                 do_count = count;
1733                         else {
1734                                 do_count = STbp->buffer_blocks * STp->block_size -
1735                                         STbp->buffer_bytes;
1736                                 if (do_count > count)
1737                                         do_count = count;
1738                         }
1739
1740                         i = append_to_buffer(b_point, STbp, do_count);
1741                         if (i) {
1742                                 retval = i;
1743                                 goto out;
1744                         }
1745                 }
1746                 count -= do_count;
1747                 b_point += do_count;
1748
1749                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1750                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1751
1752                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1753                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1754                     STbp->buffer_bytes < STbp->buffer_size) {
1755                         STp->dirty = 1;
1756                         /* Don't write a buffer that is not full enough. */
1757                         if (!async_write && count == 0)
1758                                 break;
1759                 }
1760
1761         retry_write:
1762                 if (STp->block_size == 0)
1763                         blks = transfer = do_count;
1764                 else {
1765                         if (!STbp->do_dio)
1766                                 blks = STbp->buffer_bytes;
1767                         else
1768                                 blks = do_count;
1769                         blks /= STp->block_size;
1770                         transfer = blks * STp->block_size;
1771                 }
1772                 cmd[2] = blks >> 16;
1773                 cmd[3] = blks >> 8;
1774                 cmd[4] = blks;
1775
1776                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1777                                    STp->device->request_queue->rq_timeout,
1778                                    MAX_WRITE_RETRIES, !async_write);
1779                 if (!SRpnt) {
1780                         retval = STbp->syscall_result;
1781                         goto out;
1782                 }
1783                 if (async_write && !STbp->syscall_result) {
1784                         STbp->writing = transfer;
1785                         STp->dirty = !(STbp->writing ==
1786                                        STbp->buffer_bytes);
1787                         SRpnt = NULL;  /* Prevent releasing this request! */
1788                         DEB( STp->write_pending = 1; )
1789                         break;
1790                 }
1791
1792                 if (STbp->syscall_result != 0) {
1793                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1794
1795                         DEBC_printk(STp, "Error on write:\n");
1796                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1797                                 scode = cmdstatp->sense_hdr.sense_key;
1798                                 if (cmdstatp->remainder_valid)
1799                                         undone = (int)cmdstatp->uremainder64;
1800                                 else if (STp->block_size == 0 &&
1801                                          scode == VOLUME_OVERFLOW)
1802                                         undone = transfer;
1803                                 else
1804                                         undone = 0;
1805                                 if (STp->block_size != 0)
1806                                         undone *= STp->block_size;
1807                                 if (undone <= do_count) {
1808                                         /* Only data from this write is not written */
1809                                         count += undone;
1810                                         b_point -= undone;
1811                                         do_count -= undone;
1812                                         if (STp->block_size)
1813                                                 blks = (transfer - undone) / STp->block_size;
1814                                         STps->eof = ST_EOM_OK;
1815                                         /* Continue in fixed block mode if all written
1816                                            in this request but still something left to write
1817                                            (retval left to zero)
1818                                         */
1819                                         if (STp->block_size == 0 ||
1820                                             undone > 0 || count == 0)
1821                                                 retval = (-ENOSPC); /* EOM within current request */
1822                                         DEBC_printk(STp, "EOM with %d "
1823                                                     "bytes unwritten.\n",
1824                                                     (int)count);
1825                                 } else {
1826                                         /* EOT within data buffered earlier (possible only
1827                                            in fixed block mode without direct i/o) */
1828                                         if (!retry_eot && !cmdstatp->deferred &&
1829                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1830                                                 move_buffer_data(STp->buffer, transfer - undone);
1831                                                 retry_eot = 1;
1832                                                 if (STps->drv_block >= 0) {
1833                                                         STps->drv_block += (transfer - undone) /
1834                                                                 STp->block_size;
1835                                                 }
1836                                                 STps->eof = ST_EOM_OK;
1837                                                 DEBC_printk(STp, "Retry "
1838                                                             "write of %d "
1839                                                             "bytes at EOM.\n",
1840                                                             STp->buffer->buffer_bytes);
1841                                                 goto retry_write;
1842                                         }
1843                                         else {
1844                                                 /* Either error within data buffered by driver or
1845                                                    failed retry */
1846                                                 count -= do_count;
1847                                                 blks = do_count = 0;
1848                                                 STps->eof = ST_EOM_ERROR;
1849                                                 STps->drv_block = (-1); /* Too cautious? */
1850                                                 retval = (-EIO);        /* EOM for old data */
1851                                                 DEBC_printk(STp, "EOM with "
1852                                                             "lost data.\n");
1853                                         }
1854                                 }
1855                         } else {
1856                                 count += do_count;
1857                                 STps->drv_block = (-1);         /* Too cautious? */
1858                                 retval = STbp->syscall_result;
1859                         }
1860
1861                 }
1862
1863                 if (STps->drv_block >= 0) {
1864                         if (STp->block_size == 0)
1865                                 STps->drv_block += (do_count > 0);
1866                         else
1867                                 STps->drv_block += blks;
1868                 }
1869
1870                 STbp->buffer_bytes = 0;
1871                 STp->dirty = 0;
1872
1873                 if (retval || retry_eot) {
1874                         if (count < total)
1875                                 retval = total - count;
1876                         goto out;
1877                 }
1878         }
1879
1880         if (STps->eof == ST_EOD_1)
1881                 STps->eof = ST_EOM_OK;
1882         else if (STps->eof != ST_EOM_OK)
1883                 STps->eof = ST_NOEOF;
1884         retval = total - count;
1885
1886  out:
1887         if (SRpnt != NULL)
1888                 st_release_request(SRpnt);
1889         release_buffering(STp, 0);
1890         mutex_unlock(&STp->lock);
1891
1892         return retval;
1893 }
1894 \f
1895 /* Read data from the tape. Returns zero in the normal case, one if the
1896    eof status has changed, and the negative error code in case of a
1897    fatal error. Otherwise updates the buffer and the eof state.
1898
1899    Does release user buffer mapping if it is set.
1900 */
1901 static long read_tape(struct scsi_tape *STp, long count,
1902                       struct st_request ** aSRpnt)
1903 {
1904         int transfer, blks, bytes;
1905         unsigned char cmd[MAX_COMMAND_SIZE];
1906         struct st_request *SRpnt;
1907         struct st_modedef *STm;
1908         struct st_partstat *STps;
1909         struct st_buffer *STbp;
1910         int retval = 0;
1911
1912         if (count == 0)
1913                 return 0;
1914
1915         STm = &(STp->modes[STp->current_mode]);
1916         STps = &(STp->ps[STp->partition]);
1917         if (STps->eof == ST_FM_HIT)
1918                 return 1;
1919         STbp = STp->buffer;
1920
1921         if (STp->block_size == 0)
1922                 blks = bytes = count;
1923         else {
1924                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1925                         blks = (STp->buffer)->buffer_blocks;
1926                         bytes = blks * STp->block_size;
1927                 } else {
1928                         bytes = count;
1929                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1930                                 bytes = (STp->buffer)->buffer_size;
1931                         blks = bytes / STp->block_size;
1932                         bytes = blks * STp->block_size;
1933                 }
1934         }
1935
1936         memset(cmd, 0, MAX_COMMAND_SIZE);
1937         cmd[0] = READ_6;
1938         cmd[1] = (STp->block_size != 0);
1939         if (!cmd[1] && STp->sili)
1940                 cmd[1] |= 2;
1941         cmd[2] = blks >> 16;
1942         cmd[3] = blks >> 8;
1943         cmd[4] = blks;
1944
1945         SRpnt = *aSRpnt;
1946         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1947                            STp->device->request_queue->rq_timeout,
1948                            MAX_RETRIES, 1);
1949         release_buffering(STp, 1);
1950         *aSRpnt = SRpnt;
1951         if (!SRpnt)
1952                 return STbp->syscall_result;
1953
1954         STbp->read_pointer = 0;
1955         STps->at_sm = 0;
1956
1957         /* Something to check */
1958         if (STbp->syscall_result) {
1959                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1960
1961                 retval = 1;
1962                 DEBC_printk(STp,
1963                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1964                             SRpnt->sense[0], SRpnt->sense[1],
1965                             SRpnt->sense[2], SRpnt->sense[3],
1966                             SRpnt->sense[4], SRpnt->sense[5],
1967                             SRpnt->sense[6], SRpnt->sense[7]);
1968                 if (cmdstatp->have_sense) {
1969
1970                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1971                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1972
1973                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1974                                 /* Compute the residual count */
1975                                 if (cmdstatp->remainder_valid)
1976                                         transfer = (int)cmdstatp->uremainder64;
1977                                 else
1978                                         transfer = 0;
1979                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1980                                         if (STp->block_size == 0)
1981                                                 transfer = bytes;
1982                                         /* Some drives set ILI with MEDIUM ERROR */
1983                                         cmdstatp->flags &= ~SENSE_ILI;
1984                                 }
1985
1986                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1987                                         if (STp->block_size == 0 &&
1988                                             transfer < 0) {
1989                                                 st_printk(KERN_NOTICE, STp,
1990                                                           "Failed to read %d "
1991                                                           "byte block with %d "
1992                                                           "byte transfer.\n",
1993                                                           bytes - transfer,
1994                                                           bytes);
1995                                                 if (STps->drv_block >= 0)
1996                                                         STps->drv_block += 1;
1997                                                 STbp->buffer_bytes = 0;
1998                                                 return (-ENOMEM);
1999                                         } else if (STp->block_size == 0) {
2000                                                 STbp->buffer_bytes = bytes - transfer;
2001                                         } else {
2002                                                 st_release_request(SRpnt);
2003                                                 SRpnt = *aSRpnt = NULL;
2004                                                 if (transfer == blks) { /* We did not get anything, error */
2005                                                         st_printk(KERN_NOTICE, STp,
2006                                                                   "Incorrect "
2007                                                                   "block size.\n");
2008                                                         if (STps->drv_block >= 0)
2009                                                                 STps->drv_block += blks - transfer + 1;
2010                                                         st_int_ioctl(STp, MTBSR, 1);
2011                                                         return (-EIO);
2012                                                 }
2013                                                 /* We have some data, deliver it */
2014                                                 STbp->buffer_bytes = (blks - transfer) *
2015                                                     STp->block_size;
2016                                                 DEBC_printk(STp, "ILI but "
2017                                                             "enough data "
2018                                                             "received %ld "
2019                                                             "%d.\n", count,
2020                                                             STbp->buffer_bytes);
2021                                                 if (STps->drv_block >= 0)
2022                                                         STps->drv_block += 1;
2023                                                 if (st_int_ioctl(STp, MTBSR, 1))
2024                                                         return (-EIO);
2025                                         }
2026                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2027                                         if (STps->eof != ST_FM_HIT)
2028                                                 STps->eof = ST_FM_HIT;
2029                                         else
2030                                                 STps->eof = ST_EOD_2;
2031                                         if (STp->block_size == 0)
2032                                                 STbp->buffer_bytes = 0;
2033                                         else
2034                                                 STbp->buffer_bytes =
2035                                                     bytes - transfer * STp->block_size;
2036                                         DEBC_printk(STp, "EOF detected (%d "
2037                                                     "bytes read).\n",
2038                                                     STbp->buffer_bytes);
2039                                 } else if (cmdstatp->flags & SENSE_EOM) {
2040                                         if (STps->eof == ST_FM)
2041                                                 STps->eof = ST_EOD_1;
2042                                         else
2043                                                 STps->eof = ST_EOM_OK;
2044                                         if (STp->block_size == 0)
2045                                                 STbp->buffer_bytes = bytes - transfer;
2046                                         else
2047                                                 STbp->buffer_bytes =
2048                                                     bytes - transfer * STp->block_size;
2049
2050                                         DEBC_printk(STp, "EOM detected (%d "
2051                                                     "bytes read).\n",
2052                                                     STbp->buffer_bytes);
2053                                 }
2054                         }
2055                         /* end of EOF, EOM, ILI test */
2056                         else {  /* nonzero sense key */
2057                                 DEBC_printk(STp, "Tape error while reading.\n");
2058                                 STps->drv_block = (-1);
2059                                 if (STps->eof == ST_FM &&
2060                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2061                                         DEBC_printk(STp, "Zero returned for "
2062                                                     "first BLANK CHECK "
2063                                                     "after EOF.\n");
2064                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2065                                 } else  /* Some other extended sense code */
2066                                         retval = (-EIO);
2067                         }
2068
2069                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2070                                 STbp->buffer_bytes = 0;
2071                 }
2072                 /* End of extended sense test */
2073                 else {          /* Non-extended sense */
2074                         retval = STbp->syscall_result;
2075                 }
2076
2077         }
2078         /* End of error handling */
2079         else {                  /* Read successful */
2080                 STbp->buffer_bytes = bytes;
2081                 if (STp->sili) /* In fixed block mode residual is always zero here */
2082                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2083         }
2084
2085         if (STps->drv_block >= 0) {
2086                 if (STp->block_size == 0)
2087                         STps->drv_block++;
2088                 else
2089                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2090         }
2091         return retval;
2092 }
2093 \f
2094
2095 /* Read command */
2096 static ssize_t
2097 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2098 {
2099         ssize_t total;
2100         ssize_t retval = 0;
2101         ssize_t i, transfer;
2102         int special, do_dio = 0;
2103         struct st_request *SRpnt = NULL;
2104         struct scsi_tape *STp = filp->private_data;
2105         struct st_modedef *STm;
2106         struct st_partstat *STps;
2107         struct st_buffer *STbp = STp->buffer;
2108
2109         if (mutex_lock_interruptible(&STp->lock))
2110                 return -ERESTARTSYS;
2111
2112         retval = rw_checks(STp, filp, count);
2113         if (retval || count == 0)
2114                 goto out;
2115
2116         STm = &(STp->modes[STp->current_mode]);
2117         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2118                 if (!STm->do_read_ahead) {
2119                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2120                         goto out;
2121                 }
2122                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2123         }
2124
2125         STps = &(STp->ps[STp->partition]);
2126         if (STps->rw == ST_WRITING) {
2127                 retval = flush_buffer(STp, 0);
2128                 if (retval)
2129                         goto out;
2130                 STps->rw = ST_READING;
2131         }
2132         DEB(
2133         if (debugging && STps->eof != ST_NOEOF)
2134                 st_printk(ST_DEB_MSG, STp,
2135                           "EOF/EOM flag up (%d). Bytes %d\n",
2136                           STps->eof, STbp->buffer_bytes);
2137         ) /* end DEB */
2138
2139         retval = setup_buffering(STp, buf, count, 1);
2140         if (retval)
2141                 goto out;
2142         do_dio = STbp->do_dio;
2143
2144         if (STbp->buffer_bytes == 0 &&
2145             STps->eof >= ST_EOD_1) {
2146                 if (STps->eof < ST_EOD) {
2147                         STps->eof += 1;
2148                         retval = 0;
2149                         goto out;
2150                 }
2151                 retval = (-EIO);        /* EOM or Blank Check */
2152                 goto out;
2153         }
2154
2155         if (do_dio) {
2156                 /* Check the buffer writability before any tape movement. Don't alter
2157                    buffer data. */
2158                 if (copy_from_user(&i, buf, 1) != 0 ||
2159                     copy_to_user(buf, &i, 1) != 0 ||
2160                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2161                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2162                         retval = (-EFAULT);
2163                         goto out;
2164                 }
2165         }
2166
2167         STps->rw = ST_READING;
2168
2169
2170         /* Loop until enough data in buffer or a special condition found */
2171         for (total = 0, special = 0; total < count && !special;) {
2172
2173                 /* Get new data if the buffer is empty */
2174                 if (STbp->buffer_bytes == 0) {
2175                         special = read_tape(STp, count - total, &SRpnt);
2176                         if (special < 0) {      /* No need to continue read */
2177                                 retval = special;
2178                                 goto out;
2179                         }
2180                 }
2181
2182                 /* Move the data from driver buffer to user buffer */
2183                 if (STbp->buffer_bytes > 0) {
2184                         DEB(
2185                         if (debugging && STps->eof != ST_NOEOF)
2186                                 st_printk(ST_DEB_MSG, STp,
2187                                           "EOF up (%d). Left %d, needed %d.\n",
2188                                           STps->eof, STbp->buffer_bytes,
2189                                           (int)(count - total));
2190                         ) /* end DEB */
2191                         transfer = STbp->buffer_bytes < count - total ?
2192                             STbp->buffer_bytes : count - total;
2193                         if (!do_dio) {
2194                                 i = from_buffer(STbp, buf, transfer);
2195                                 if (i) {
2196                                         retval = i;
2197                                         goto out;
2198                                 }
2199                         }
2200                         buf += transfer;
2201                         total += transfer;
2202                 }
2203
2204                 if (STp->block_size == 0)
2205                         break;  /* Read only one variable length block */
2206
2207         }                       /* for (total = 0, special = 0;
2208                                    total < count && !special; ) */
2209
2210         /* Change the eof state if no data from tape or buffer */
2211         if (total == 0) {
2212                 if (STps->eof == ST_FM_HIT) {
2213                         STps->eof = ST_FM;
2214                         STps->drv_block = 0;
2215                         if (STps->drv_file >= 0)
2216                                 STps->drv_file++;
2217                 } else if (STps->eof == ST_EOD_1) {
2218                         STps->eof = ST_EOD_2;
2219                         STps->drv_block = 0;
2220                         if (STps->drv_file >= 0)
2221                                 STps->drv_file++;
2222                 } else if (STps->eof == ST_EOD_2)
2223                         STps->eof = ST_EOD;
2224         } else if (STps->eof == ST_FM)
2225                 STps->eof = ST_NOEOF;
2226         retval = total;
2227
2228  out:
2229         if (SRpnt != NULL) {
2230                 st_release_request(SRpnt);
2231                 SRpnt = NULL;
2232         }
2233         if (do_dio) {
2234                 release_buffering(STp, 1);
2235                 STbp->buffer_bytes = 0;
2236         }
2237         mutex_unlock(&STp->lock);
2238
2239         return retval;
2240 }
2241 \f
2242
2243
2244 DEB(
2245 /* Set the driver options */
2246 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2247 {
2248         if (debugging) {
2249                 st_printk(KERN_INFO, STp,
2250                           "Mode %d options: buffer writes: %d, "
2251                           "async writes: %d, read ahead: %d\n",
2252                           STp->current_mode, STm->do_buffer_writes,
2253                           STm->do_async_writes, STm->do_read_ahead);
2254                 st_printk(KERN_INFO, STp,
2255                           "    can bsr: %d, two FMs: %d, "
2256                           "fast mteom: %d, auto lock: %d,\n",
2257                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2258                           STp->do_auto_lock);
2259                 st_printk(KERN_INFO, STp,
2260                           "    defs for wr: %d, no block limits: %d, "
2261                           "partitions: %d, s2 log: %d\n",
2262                           STm->defaults_for_writes, STp->omit_blklims,
2263                           STp->can_partitions, STp->scsi2_logical);
2264                 st_printk(KERN_INFO, STp,
2265                           "    sysv: %d nowait: %d sili: %d "
2266                           "nowait_filemark: %d\n",
2267                           STm->sysv, STp->immediate, STp->sili,
2268                           STp->immediate_filemark);
2269                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2270         }
2271 }
2272         )
2273
2274
2275 static int st_set_options(struct scsi_tape *STp, long options)
2276 {
2277         int value;
2278         long code;
2279         struct st_modedef *STm;
2280         struct cdev *cd0, *cd1;
2281         struct device *d0, *d1;
2282
2283         STm = &(STp->modes[STp->current_mode]);
2284         if (!STm->defined) {
2285                 cd0 = STm->cdevs[0];
2286                 cd1 = STm->cdevs[1];
2287                 d0  = STm->devs[0];
2288                 d1  = STm->devs[1];
2289                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2290                 STm->cdevs[0] = cd0;
2291                 STm->cdevs[1] = cd1;
2292                 STm->devs[0]  = d0;
2293                 STm->devs[1]  = d1;
2294                 modes_defined = 1;
2295                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2296                             STp->current_mode);
2297         }
2298
2299         code = options & MT_ST_OPTIONS;
2300         if (code == MT_ST_BOOLEANS) {
2301                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2302                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2303                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2304                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2305                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2306                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2307                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2308                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2309                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2310                 if ((STp->device)->scsi_level >= SCSI_2)
2311                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2312                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2313                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2314                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2315                 STm->sysv = (options & MT_ST_SYSV) != 0;
2316                 STp->sili = (options & MT_ST_SILI) != 0;
2317                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2318                      st_log_options(STp, STm); )
2319         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2320                 value = (code == MT_ST_SETBOOLEANS);
2321                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2322                         STm->do_buffer_writes = value;
2323                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2324                         STm->do_async_writes = value;
2325                 if ((options & MT_ST_DEF_WRITES) != 0)
2326                         STm->defaults_for_writes = value;
2327                 if ((options & MT_ST_READ_AHEAD) != 0)
2328                         STm->do_read_ahead = value;
2329                 if ((options & MT_ST_TWO_FM) != 0)
2330                         STp->two_fm = value;
2331                 if ((options & MT_ST_FAST_MTEOM) != 0)
2332                         STp->fast_mteom = value;
2333                 if ((options & MT_ST_AUTO_LOCK) != 0)
2334                         STp->do_auto_lock = value;
2335                 if ((options & MT_ST_CAN_BSR) != 0)
2336                         STp->can_bsr = value;
2337                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2338                         STp->omit_blklims = value;
2339                 if ((STp->device)->scsi_level >= SCSI_2 &&
2340                     (options & MT_ST_CAN_PARTITIONS) != 0)
2341                         STp->can_partitions = value;
2342                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2343                         STp->scsi2_logical = value;
2344                 if ((options & MT_ST_NOWAIT) != 0)
2345                         STp->immediate = value;
2346                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2347                         STp->immediate_filemark = value;
2348                 if ((options & MT_ST_SYSV) != 0)
2349                         STm->sysv = value;
2350                 if ((options & MT_ST_SILI) != 0)
2351                         STp->sili = value;
2352                 DEB(
2353                 if ((options & MT_ST_DEBUGGING) != 0)
2354                         debugging = value;
2355                         st_log_options(STp, STm); )
2356         } else if (code == MT_ST_WRITE_THRESHOLD) {
2357                 /* Retained for compatibility */
2358         } else if (code == MT_ST_DEF_BLKSIZE) {
2359                 value = (options & ~MT_ST_OPTIONS);
2360                 if (value == ~MT_ST_OPTIONS) {
2361                         STm->default_blksize = (-1);
2362                         DEBC_printk(STp, "Default block size disabled.\n");
2363                 } else {
2364                         STm->default_blksize = value;
2365                         DEBC_printk(STp,"Default block size set to "
2366                                     "%d bytes.\n", STm->default_blksize);
2367                         if (STp->ready == ST_READY) {
2368                                 STp->blksize_changed = 0;
2369                                 set_mode_densblk(STp, STm);
2370                         }
2371                 }
2372         } else if (code == MT_ST_TIMEOUTS) {
2373                 value = (options & ~MT_ST_OPTIONS);
2374                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2375                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2376                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2377                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2378                 } else {
2379                         blk_queue_rq_timeout(STp->device->request_queue,
2380                                              value * HZ);
2381                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2382                                     value);
2383                 }
2384         } else if (code == MT_ST_SET_CLN) {
2385                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2386                 if (value != 0 &&
2387                         (value < EXTENDED_SENSE_START ||
2388                                 value >= SCSI_SENSE_BUFFERSIZE))
2389                         return (-EINVAL);
2390                 STp->cln_mode = value;
2391                 STp->cln_sense_mask = (options >> 8) & 0xff;
2392                 STp->cln_sense_value = (options >> 16) & 0xff;
2393                 st_printk(KERN_INFO, STp,
2394                           "Cleaning request mode %d, mask %02x, value %02x\n",
2395                           value, STp->cln_sense_mask, STp->cln_sense_value);
2396         } else if (code == MT_ST_DEF_OPTIONS) {
2397                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2398                 value = (options & MT_ST_CLEAR_DEFAULT);
2399                 if (code == MT_ST_DEF_DENSITY) {
2400                         if (value == MT_ST_CLEAR_DEFAULT) {
2401                                 STm->default_density = (-1);
2402                                 DEBC_printk(STp,
2403                                             "Density default disabled.\n");
2404                         } else {
2405                                 STm->default_density = value & 0xff;
2406                                 DEBC_printk(STp, "Density default set to %x\n",
2407                                             STm->default_density);
2408                                 if (STp->ready == ST_READY) {
2409                                         STp->density_changed = 0;
2410                                         set_mode_densblk(STp, STm);
2411                                 }
2412                         }
2413                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2414                         if (value == MT_ST_CLEAR_DEFAULT) {
2415                                 STp->default_drvbuffer = 0xff;
2416                                 DEBC_printk(STp,
2417                                             "Drive buffer default disabled.\n");
2418                         } else {
2419                                 STp->default_drvbuffer = value & 7;
2420                                 DEBC_printk(STp,
2421                                             "Drive buffer default set to %x\n",
2422                                             STp->default_drvbuffer);
2423                                 if (STp->ready == ST_READY)
2424                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2425                         }
2426                 } else if (code == MT_ST_DEF_COMPRESSION) {
2427                         if (value == MT_ST_CLEAR_DEFAULT) {
2428                                 STm->default_compression = ST_DONT_TOUCH;
2429                                 DEBC_printk(STp,
2430                                             "Compression default disabled.\n");
2431                         } else {
2432                                 if ((value & 0xff00) != 0) {
2433                                         STp->c_algo = (value & 0xff00) >> 8;
2434                                         DEBC_printk(STp, "Compression "
2435                                                     "algorithm set to 0x%x.\n",
2436                                                     STp->c_algo);
2437                                 }
2438                                 if ((value & 0xff) != 0xff) {
2439                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2440                                         DEBC_printk(STp, "Compression default "
2441                                                     "set to %x\n",
2442                                                     (value & 1));
2443                                         if (STp->ready == ST_READY) {
2444                                                 STp->compression_changed = 0;
2445                                                 st_compression(STp, (STm->default_compression == ST_YES));
2446                                         }
2447                                 }
2448                         }
2449                 }
2450         } else
2451                 return (-EIO);
2452
2453         return 0;
2454 }
2455 \f
2456 #define MODE_HEADER_LENGTH  4
2457
2458 /* Mode header and page byte offsets */
2459 #define MH_OFF_DATA_LENGTH     0
2460 #define MH_OFF_MEDIUM_TYPE     1
2461 #define MH_OFF_DEV_SPECIFIC    2
2462 #define MH_OFF_BDESCS_LENGTH   3
2463 #define MP_OFF_PAGE_NBR        0
2464 #define MP_OFF_PAGE_LENGTH     1
2465
2466 /* Mode header and page bit masks */
2467 #define MH_BIT_WP              0x80
2468 #define MP_MSK_PAGE_NBR        0x3f
2469
2470 /* Don't return block descriptors */
2471 #define MODE_SENSE_OMIT_BDESCS 0x08
2472
2473 #define MODE_SELECT_PAGE_FORMAT 0x10
2474
2475 /* Read a mode page into the tape buffer. The block descriptors are included
2476    if incl_block_descs is true. The page control is ored to the page number
2477    parameter, if necessary. */
2478 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2479 {
2480         unsigned char cmd[MAX_COMMAND_SIZE];
2481         struct st_request *SRpnt;
2482
2483         memset(cmd, 0, MAX_COMMAND_SIZE);
2484         cmd[0] = MODE_SENSE;
2485         if (omit_block_descs)
2486                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2487         cmd[2] = page;
2488         cmd[4] = 255;
2489
2490         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2491                            STp->device->request_queue->rq_timeout, 0, 1);
2492         if (SRpnt == NULL)
2493                 return (STp->buffer)->syscall_result;
2494
2495         st_release_request(SRpnt);
2496
2497         return STp->buffer->syscall_result;
2498 }
2499
2500
2501 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2502    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2503 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2504 {
2505         int pgo;
2506         unsigned char cmd[MAX_COMMAND_SIZE];
2507         struct st_request *SRpnt;
2508         int timeout;
2509
2510         memset(cmd, 0, MAX_COMMAND_SIZE);
2511         cmd[0] = MODE_SELECT;
2512         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2513         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2514         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2515
2516         /* Clear reserved fields */
2517         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2518         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2519         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2520         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2521
2522         timeout = slow ?
2523                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2524         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2525                            timeout, 0, 1);
2526         if (SRpnt == NULL)
2527                 return (STp->buffer)->syscall_result;
2528
2529         st_release_request(SRpnt);
2530
2531         return STp->buffer->syscall_result;
2532 }
2533
2534
2535 #define COMPRESSION_PAGE        0x0f
2536 #define COMPRESSION_PAGE_LENGTH 16
2537
2538 #define CP_OFF_DCE_DCC          2
2539 #define CP_OFF_C_ALGO           7
2540
2541 #define DCE_MASK  0x80
2542 #define DCC_MASK  0x40
2543 #define RED_MASK  0x60
2544
2545
2546 /* Control the compression with mode page 15. Algorithm not changed if zero.
2547
2548    The block descriptors are read and written because Sony SDT-7000 does not
2549    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2550    Including block descriptors should not cause any harm to other drives. */
2551
2552 static int st_compression(struct scsi_tape * STp, int state)
2553 {
2554         int retval;
2555         int mpoffs;  /* Offset to mode page start */
2556         unsigned char *b_data = (STp->buffer)->b_data;
2557
2558         if (STp->ready != ST_READY)
2559                 return (-EIO);
2560
2561         /* Read the current page contents */
2562         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2563         if (retval) {
2564                 DEBC_printk(STp, "Compression mode page not supported.\n");
2565                 return (-EIO);
2566         }
2567
2568         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2569         DEBC_printk(STp, "Compression state is %d.\n",
2570                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2571
2572         /* Check if compression can be changed */
2573         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2574                 DEBC_printk(STp, "Compression not supported.\n");
2575                 return (-EIO);
2576         }
2577
2578         /* Do the change */
2579         if (state) {
2580                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2581                 if (STp->c_algo != 0)
2582                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2583         }
2584         else {
2585                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2586                 if (STp->c_algo != 0)
2587                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2588         }
2589
2590         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2591         if (retval) {
2592                 DEBC_printk(STp, "Compression change failed.\n");
2593                 return (-EIO);
2594         }
2595         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2596
2597         STp->compression_changed = 1;
2598         return 0;
2599 }
2600
2601
2602 /* Process the load and unload commands (does unload if the load code is zero) */
2603 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2604 {
2605         int retval = (-EIO), timeout;
2606         unsigned char cmd[MAX_COMMAND_SIZE];
2607         struct st_partstat *STps;
2608         struct st_request *SRpnt;
2609
2610         if (STp->ready != ST_READY && !load_code) {
2611                 if (STp->ready == ST_NO_TAPE)
2612                         return (-ENOMEDIUM);
2613                 else
2614                         return (-EIO);
2615         }
2616
2617         memset(cmd, 0, MAX_COMMAND_SIZE);
2618         cmd[0] = START_STOP;
2619         if (load_code)
2620                 cmd[4] |= 1;
2621         /*
2622          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2623          */
2624         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2625             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2626                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2627                             (cmd[4]) ? "" : "un",
2628                             load_code - MT_ST_HPLOADER_OFFSET);
2629                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2630         }
2631         if (STp->immediate) {
2632                 cmd[1] = 1;     /* Don't wait for completion */
2633                 timeout = STp->device->request_queue->rq_timeout;
2634         }
2635         else
2636                 timeout = STp->long_timeout;
2637
2638         DEBC(
2639                 if (!load_code)
2640                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2641                 else
2642                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2643                 );
2644
2645         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2646                            timeout, MAX_RETRIES, 1);
2647         if (!SRpnt)
2648                 return (STp->buffer)->syscall_result;
2649
2650         retval = (STp->buffer)->syscall_result;
2651         st_release_request(SRpnt);
2652
2653         if (!retval) {  /* SCSI command successful */
2654
2655                 if (!load_code) {
2656                         STp->rew_at_close = 0;
2657                         STp->ready = ST_NO_TAPE;
2658                 }
2659                 else {
2660                         STp->rew_at_close = STp->autorew_dev;
2661                         retval = check_tape(STp, filp);
2662                         if (retval > 0)
2663                                 retval = 0;
2664                 }
2665         }
2666         else {
2667                 STps = &(STp->ps[STp->partition]);
2668                 STps->drv_file = STps->drv_block = (-1);
2669         }
2670
2671         return retval;
2672 }
2673 \f
2674 #if DEBUG
2675 #define ST_DEB_FORWARD  0
2676 #define ST_DEB_BACKWARD 1
2677 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2678 {
2679         s32 sc;
2680
2681         if (!debugging)
2682                 return;
2683
2684         sc = sign_extend32(get_unaligned_be24(&cmd[2]), 23);
2685         if (direction)
2686                 sc = -sc;
2687         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688                   direction ? "backward" : "forward", sc, units);
2689 }
2690 #else
2691 #define ST_DEB_FORWARD  0
2692 #define ST_DEB_BACKWARD 1
2693 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694 #endif
2695
2696
2697 /* Internal ioctl function */
2698 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699 {
2700         int timeout;
2701         long ltmp;
2702         int ioctl_result;
2703         int chg_eof = 1;
2704         unsigned char cmd[MAX_COMMAND_SIZE];
2705         struct st_request *SRpnt;
2706         struct st_partstat *STps;
2707         int fileno, blkno, at_sm, undone;
2708         int datalen = 0, direction = DMA_NONE;
2709
2710         WARN_ON(STp->buffer->do_dio != 0);
2711         if (STp->ready != ST_READY) {
2712                 if (STp->ready == ST_NO_TAPE)
2713                         return (-ENOMEDIUM);
2714                 else
2715                         return (-EIO);
2716         }
2717         timeout = STp->long_timeout;
2718         STps = &(STp->ps[STp->partition]);
2719         fileno = STps->drv_file;
2720         blkno = STps->drv_block;
2721         at_sm = STps->at_sm;
2722
2723         memset(cmd, 0, MAX_COMMAND_SIZE);
2724         switch (cmd_in) {
2725         case MTFSFM:
2726                 chg_eof = 0;    /* Changed from the FSF after this */
2727                 /* fall through */
2728         case MTFSF:
2729                 cmd[0] = SPACE;
2730                 cmd[1] = 0x01;  /* Space FileMarks */
2731                 cmd[2] = (arg >> 16);
2732                 cmd[3] = (arg >> 8);
2733                 cmd[4] = arg;
2734                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735                 if (fileno >= 0)
2736                         fileno += arg;
2737                 blkno = 0;
2738                 at_sm &= (arg == 0);
2739                 break;
2740         case MTBSFM:
2741                 chg_eof = 0;    /* Changed from the FSF after this */
2742                 /* fall through */
2743         case MTBSF:
2744                 cmd[0] = SPACE;
2745                 cmd[1] = 0x01;  /* Space FileMarks */
2746                 ltmp = (-arg);
2747                 cmd[2] = (ltmp >> 16);
2748                 cmd[3] = (ltmp >> 8);
2749                 cmd[4] = ltmp;
2750                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2751                 if (fileno >= 0)
2752                         fileno -= arg;
2753                 blkno = (-1);   /* We can't know the block number */
2754                 at_sm &= (arg == 0);
2755                 break;
2756         case MTFSR:
2757                 cmd[0] = SPACE;
2758                 cmd[1] = 0x00;  /* Space Blocks */
2759                 cmd[2] = (arg >> 16);
2760                 cmd[3] = (arg >> 8);
2761                 cmd[4] = arg;
2762                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2763                 if (blkno >= 0)
2764                         blkno += arg;
2765                 at_sm &= (arg == 0);
2766                 break;
2767         case MTBSR:
2768                 cmd[0] = SPACE;
2769                 cmd[1] = 0x00;  /* Space Blocks */
2770                 ltmp = (-arg);
2771                 cmd[2] = (ltmp >> 16);
2772                 cmd[3] = (ltmp >> 8);
2773                 cmd[4] = ltmp;
2774                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2775                 if (blkno >= 0)
2776                         blkno -= arg;
2777                 at_sm &= (arg == 0);
2778                 break;
2779         case MTFSS:
2780                 cmd[0] = SPACE;
2781                 cmd[1] = 0x04;  /* Space Setmarks */
2782                 cmd[2] = (arg >> 16);
2783                 cmd[3] = (arg >> 8);
2784                 cmd[4] = arg;
2785                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2786                 if (arg != 0) {
2787                         blkno = fileno = (-1);
2788                         at_sm = 1;
2789                 }
2790                 break;
2791         case MTBSS:
2792                 cmd[0] = SPACE;
2793                 cmd[1] = 0x04;  /* Space Setmarks */
2794                 ltmp = (-arg);
2795                 cmd[2] = (ltmp >> 16);
2796                 cmd[3] = (ltmp >> 8);
2797                 cmd[4] = ltmp;
2798                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2799                 if (arg != 0) {
2800                         blkno = fileno = (-1);
2801                         at_sm = 1;
2802                 }
2803                 break;
2804         case MTWEOF:
2805         case MTWEOFI:
2806         case MTWSM:
2807                 if (STp->write_prot)
2808                         return (-EACCES);
2809                 cmd[0] = WRITE_FILEMARKS;
2810                 if (cmd_in == MTWSM)
2811                         cmd[1] = 2;
2812                 if (cmd_in == MTWEOFI ||
2813                     (cmd_in == MTWEOF && STp->immediate_filemark))
2814                         cmd[1] |= 1;
2815                 cmd[2] = (arg >> 16);
2816                 cmd[3] = (arg >> 8);
2817                 cmd[4] = arg;
2818                 timeout = STp->device->request_queue->rq_timeout;
2819                 DEBC(
2820                         if (cmd_in != MTWSM)
2821                                 st_printk(ST_DEB_MSG, STp,
2822                                           "Writing %d filemarks.\n",
2823                                           cmd[2] * 65536 +
2824                                           cmd[3] * 256 +
2825                                           cmd[4]);
2826                         else
2827                                 st_printk(ST_DEB_MSG, STp,
2828                                           "Writing %d setmarks.\n",
2829                                           cmd[2] * 65536 +
2830                                           cmd[3] * 256 +
2831                                           cmd[4]);
2832                 )
2833                 if (fileno >= 0)
2834                         fileno += arg;
2835                 blkno = 0;
2836                 at_sm = (cmd_in == MTWSM);
2837                 break;
2838         case MTREW:
2839                 cmd[0] = REZERO_UNIT;
2840                 if (STp->immediate) {
2841                         cmd[1] = 1;     /* Don't wait for completion */
2842                         timeout = STp->device->request_queue->rq_timeout;
2843                 }
2844                 DEBC_printk(STp, "Rewinding tape.\n");
2845                 fileno = blkno = at_sm = 0;
2846                 break;
2847         case MTNOP:
2848                 DEBC_printk(STp, "No op on tape.\n");
2849                 return 0;       /* Should do something ? */
2850                 break;
2851         case MTRETEN:
2852                 cmd[0] = START_STOP;
2853                 if (STp->immediate) {
2854                         cmd[1] = 1;     /* Don't wait for completion */
2855                         timeout = STp->device->request_queue->rq_timeout;
2856                 }
2857                 cmd[4] = 3;
2858                 DEBC_printk(STp, "Retensioning tape.\n");
2859                 fileno = blkno = at_sm = 0;
2860                 break;
2861         case MTEOM:
2862                 if (!STp->fast_mteom) {
2863                         /* space to the end of tape */
2864                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2865                         fileno = STps->drv_file;
2866                         if (STps->eof >= ST_EOD_1)
2867                                 return 0;
2868                         /* The next lines would hide the number of spaced FileMarks
2869                            That's why I inserted the previous lines. I had no luck
2870                            with detecting EOM with FSF, so we go now to EOM.
2871                            Joerg Weule */
2872                 } else
2873                         fileno = (-1);
2874                 cmd[0] = SPACE;
2875                 cmd[1] = 3;
2876                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2877                 blkno = -1;
2878                 at_sm = 0;
2879                 break;
2880         case MTERASE:
2881                 if (STp->write_prot)
2882                         return (-EACCES);
2883                 cmd[0] = ERASE;
2884                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2885                 if (STp->immediate) {
2886                         cmd[1] |= 2;    /* Don't wait for completion */
2887                         timeout = STp->device->request_queue->rq_timeout;
2888                 }
2889                 else
2890                         timeout = STp->long_timeout * 8;
2891
2892                 DEBC_printk(STp, "Erasing tape.\n");
2893                 fileno = blkno = at_sm = 0;
2894                 break;
2895         case MTSETBLK:          /* Set block length */
2896         case MTSETDENSITY:      /* Set tape density */
2897         case MTSETDRVBUFFER:    /* Set drive buffering */
2898         case SET_DENS_AND_BLK:  /* Set density and block size */
2899                 chg_eof = 0;
2900                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2901                         return (-EIO);  /* Not allowed if data in buffer */
2902                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2903                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2904                     STp->max_block > 0 &&
2905                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2906                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2907                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2908                         return (-EINVAL);
2909                 }
2910                 cmd[0] = MODE_SELECT;
2911                 if ((STp->use_pf & USE_PF))
2912                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2913                 cmd[4] = datalen = 12;
2914                 direction = DMA_TO_DEVICE;
2915
2916                 memset((STp->buffer)->b_data, 0, 12);
2917                 if (cmd_in == MTSETDRVBUFFER)
2918                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2919                 else
2920                         (STp->buffer)->b_data[2] =
2921                             STp->drv_buffer << 4;
2922                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2923                 if (cmd_in == MTSETDENSITY) {
2924                         (STp->buffer)->b_data[4] = arg;
2925                         STp->density_changed = 1;       /* At least we tried ;-) */
2926                 } else if (cmd_in == SET_DENS_AND_BLK)
2927                         (STp->buffer)->b_data[4] = arg >> 24;
2928                 else
2929                         (STp->buffer)->b_data[4] = STp->density;
2930                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2931                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2932                         if (cmd_in == MTSETBLK)
2933                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2934                 } else
2935                         ltmp = STp->block_size;
2936                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2937                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2938                 (STp->buffer)->b_data[11] = ltmp;
2939                 timeout = STp->device->request_queue->rq_timeout;
2940                 DEBC(
2941                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2942                                 st_printk(ST_DEB_MSG, STp,
2943                                           "Setting block size to %d bytes.\n",
2944                                           (STp->buffer)->b_data[9] * 65536 +
2945                                           (STp->buffer)->b_data[10] * 256 +
2946                                           (STp->buffer)->b_data[11]);
2947                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2948                                 st_printk(ST_DEB_MSG, STp,
2949                                           "Setting density code to %x.\n",
2950                                           (STp->buffer)->b_data[4]);
2951                         if (cmd_in == MTSETDRVBUFFER)
2952                                 st_printk(ST_DEB_MSG, STp,
2953                                           "Setting drive buffer code to %d.\n",
2954                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2955                 )
2956                 break;
2957         default:
2958                 return (-ENOSYS);
2959         }
2960
2961         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2962                            timeout, MAX_RETRIES, 1);
2963         if (!SRpnt)
2964                 return (STp->buffer)->syscall_result;
2965
2966         ioctl_result = (STp->buffer)->syscall_result;
2967
2968         if (!ioctl_result) {    /* SCSI command successful */
2969                 st_release_request(SRpnt);
2970                 SRpnt = NULL;
2971                 STps->drv_block = blkno;
2972                 STps->drv_file = fileno;
2973                 STps->at_sm = at_sm;
2974
2975                 if (cmd_in == MTBSFM)
2976                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2977                 else if (cmd_in == MTFSFM)
2978                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2979
2980                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2981                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2982                         if (STp->block_size != 0) {
2983                                 (STp->buffer)->buffer_blocks =
2984                                     (STp->buffer)->buffer_size / STp->block_size;
2985                         }
2986                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2987                         if (cmd_in == SET_DENS_AND_BLK)
2988                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2989                 } else if (cmd_in == MTSETDRVBUFFER)
2990                         STp->drv_buffer = (arg & 7);
2991                 else if (cmd_in == MTSETDENSITY)
2992                         STp->density = arg;
2993
2994                 if (cmd_in == MTEOM)
2995                         STps->eof = ST_EOD;
2996                 else if (cmd_in == MTFSF)
2997                         STps->eof = ST_FM;
2998                 else if (chg_eof)
2999                         STps->eof = ST_NOEOF;
3000
3001                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3002                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3003         } else { /* SCSI command was not completely successful. Don't return
3004                     from this block without releasing the SCSI command block! */
3005                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3006
3007                 if (cmdstatp->flags & SENSE_EOM) {
3008                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3009                             cmd_in != MTBSR && cmd_in != MTBSS)
3010                                 STps->eof = ST_EOM_OK;
3011                         STps->drv_block = 0;
3012                 }
3013
3014                 if (cmdstatp->remainder_valid)
3015                         undone = (int)cmdstatp->uremainder64;
3016                 else
3017                         undone = 0;
3018
3019                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3020                     cmdstatp->have_sense &&
3021                     (cmdstatp->flags & SENSE_EOM)) {
3022                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3023                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3024                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3025                                 STps->eof = ST_NOEOF;
3026                         } else {  /* Writing EOF(s) failed */
3027                                 if (fileno >= 0)
3028                                         fileno -= undone;
3029                                 if (undone < arg)
3030                                         STps->eof = ST_NOEOF;
3031                         }
3032                         STps->drv_file = fileno;
3033                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3034                         if (fileno >= 0)
3035                                 STps->drv_file = fileno - undone;
3036                         else
3037                                 STps->drv_file = fileno;
3038                         STps->drv_block = -1;
3039                         STps->eof = ST_NOEOF;
3040                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3041                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3042                                 undone = (-undone);
3043                         if (STps->drv_file >= 0)
3044                                 STps->drv_file = fileno + undone;
3045                         STps->drv_block = 0;
3046                         STps->eof = ST_NOEOF;
3047                 } else if (cmd_in == MTFSR) {
3048                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3049                                 if (STps->drv_file >= 0)
3050                                         STps->drv_file++;
3051                                 STps->drv_block = 0;
3052                                 STps->eof = ST_FM;
3053                         } else {
3054                                 if (blkno >= undone)
3055                                         STps->drv_block = blkno - undone;
3056                                 else
3057                                         STps->drv_block = (-1);
3058                                 STps->eof = ST_NOEOF;
3059                         }
3060                 } else if (cmd_in == MTBSR) {
3061                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3062                                 STps->drv_file--;
3063                                 STps->drv_block = (-1);
3064                         } else {
3065                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3066                                         undone = (-undone);
3067                                 if (STps->drv_block >= 0)
3068                                         STps->drv_block = blkno + undone;
3069                         }
3070                         STps->eof = ST_NOEOF;
3071                 } else if (cmd_in == MTEOM) {
3072                         STps->drv_file = (-1);
3073                         STps->drv_block = (-1);
3074                         STps->eof = ST_EOD;
3075                 } else if (cmd_in == MTSETBLK ||
3076                            cmd_in == MTSETDENSITY ||
3077                            cmd_in == MTSETDRVBUFFER ||
3078                            cmd_in == SET_DENS_AND_BLK) {
3079                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3080                             !(STp->use_pf & PF_TESTED)) {
3081                                 /* Try the other possible state of Page Format if not
3082                                    already tried */
3083                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3084                                 st_release_request(SRpnt);
3085                                 SRpnt = NULL;
3086                                 return st_int_ioctl(STp, cmd_in, arg);
3087                         }
3088                 } else if (chg_eof)
3089                         STps->eof = ST_NOEOF;
3090
3091                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3092                         STps->eof = ST_EOD;
3093
3094                 st_release_request(SRpnt);
3095                 SRpnt = NULL;
3096         }
3097
3098         return ioctl_result;
3099 }
3100 \f
3101
3102 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3103    structure. */
3104
3105 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3106                         int logical)
3107 {
3108         int result;
3109         unsigned char scmd[MAX_COMMAND_SIZE];
3110         struct st_request *SRpnt;
3111
3112         if (STp->ready != ST_READY)
3113                 return (-EIO);
3114
3115         memset(scmd, 0, MAX_COMMAND_SIZE);
3116         if ((STp->device)->scsi_level < SCSI_2) {
3117                 scmd[0] = QFA_REQUEST_BLOCK;
3118                 scmd[4] = 3;
3119         } else {
3120                 scmd[0] = READ_POSITION;
3121                 if (!logical && !STp->scsi2_logical)
3122                         scmd[1] = 1;
3123         }
3124         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3125                            STp->device->request_queue->rq_timeout,
3126                            MAX_READY_RETRIES, 1);
3127         if (!SRpnt)
3128                 return (STp->buffer)->syscall_result;
3129
3130         if ((STp->buffer)->syscall_result != 0 ||
3131             (STp->device->scsi_level >= SCSI_2 &&
3132              ((STp->buffer)->b_data[0] & 4) != 0)) {
3133                 *block = *partition = 0;
3134                 DEBC_printk(STp, " Can't read tape position.\n");
3135                 result = (-EIO);
3136         } else {
3137                 result = 0;
3138                 if ((STp->device)->scsi_level < SCSI_2) {
3139                         *block = ((STp->buffer)->b_data[0] << 16)
3140                             + ((STp->buffer)->b_data[1] << 8)
3141                             + (STp->buffer)->b_data[2];
3142                         *partition = 0;
3143                 } else {
3144                         *block = ((STp->buffer)->b_data[4] << 24)
3145                             + ((STp->buffer)->b_data[5] << 16)
3146                             + ((STp->buffer)->b_data[6] << 8)
3147                             + (STp->buffer)->b_data[7];
3148                         *partition = (STp->buffer)->b_data[1];
3149                         if (((STp->buffer)->b_data[0] & 0x80) &&
3150                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3151                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3152                 }
3153                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3154                             *block, *partition);
3155         }
3156         st_release_request(SRpnt);
3157         SRpnt = NULL;
3158
3159         return result;
3160 }
3161
3162
3163 /* Set the tape block and partition. Negative partition means that only the
3164    block should be set in vendor specific way. */
3165 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3166                         int logical)
3167 {
3168         struct st_partstat *STps;
3169         int result, p;
3170         unsigned int blk;
3171         int timeout;
3172         unsigned char scmd[MAX_COMMAND_SIZE];
3173         struct st_request *SRpnt;
3174
3175         if (STp->ready != ST_READY)
3176                 return (-EIO);
3177         timeout = STp->long_timeout;
3178         STps = &(STp->ps[STp->partition]);
3179
3180         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3181                     block, partition);
3182         DEB(if (partition < 0)
3183                 return (-EIO); )
3184
3185         /* Update the location at the partition we are leaving */
3186         if ((!STp->can_partitions && partition != 0) ||
3187             partition >= ST_NBR_PARTITIONS)
3188                 return (-EINVAL);
3189         if (partition != STp->partition) {
3190                 if (get_location(STp, &blk, &p, 1))
3191                         STps->last_block_valid = 0;
3192                 else {
3193                         STps->last_block_valid = 1;
3194                         STps->last_block_visited = blk;
3195                         DEBC_printk(STp, "Visited block %d for "
3196                                     "partition %d saved.\n",
3197                                     blk, STp->partition);
3198                 }
3199         }
3200
3201         memset(scmd, 0, MAX_COMMAND_SIZE);
3202         if ((STp->device)->scsi_level < SCSI_2) {
3203                 scmd[0] = QFA_SEEK_BLOCK;
3204                 scmd[2] = (block >> 16);
3205                 scmd[3] = (block >> 8);
3206                 scmd[4] = block;
3207                 scmd[5] = 0;
3208         } else {
3209                 scmd[0] = SEEK_10;
3210                 scmd[3] = (block >> 24);
3211                 scmd[4] = (block >> 16);
3212                 scmd[5] = (block >> 8);
3213                 scmd[6] = block;
3214                 if (!logical && !STp->scsi2_logical)
3215                         scmd[1] = 4;
3216                 if (STp->partition != partition) {
3217                         scmd[1] |= 2;
3218                         scmd[8] = partition;
3219                         DEBC_printk(STp, "Trying to change partition "
3220                                     "from %d to %d\n", STp->partition,
3221                                     partition);
3222                 }
3223         }
3224         if (STp->immediate) {
3225                 scmd[1] |= 1;           /* Don't wait for completion */
3226                 timeout = STp->device->request_queue->rq_timeout;
3227         }
3228
3229         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3230                            timeout, MAX_READY_RETRIES, 1);
3231         if (!SRpnt)
3232                 return (STp->buffer)->syscall_result;
3233
3234         STps->drv_block = STps->drv_file = (-1);
3235         STps->eof = ST_NOEOF;
3236         if ((STp->buffer)->syscall_result != 0) {
3237                 result = (-EIO);
3238                 if (STp->can_partitions &&
3239                     (STp->device)->scsi_level >= SCSI_2 &&
3240                     (p = find_partition(STp)) >= 0)
3241                         STp->partition = p;
3242         } else {
3243                 if (STp->can_partitions) {
3244                         STp->partition = partition;
3245                         STps = &(STp->ps[partition]);
3246                         if (!STps->last_block_valid ||
3247                             STps->last_block_visited != block) {
3248                                 STps->at_sm = 0;
3249                                 STps->rw = ST_IDLE;
3250                         }
3251                 } else
3252                         STps->at_sm = 0;
3253                 if (block == 0)
3254                         STps->drv_block = STps->drv_file = 0;
3255                 result = 0;
3256         }
3257
3258         st_release_request(SRpnt);
3259         SRpnt = NULL;
3260
3261         return result;
3262 }
3263
3264
3265 /* Find the current partition number for the drive status. Called from open and
3266    returns either partition number of negative error code. */
3267 static int find_partition(struct scsi_tape *STp)
3268 {
3269         int i, partition;
3270         unsigned int block;
3271
3272         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3273                 return i;
3274         if (partition >= ST_NBR_PARTITIONS)
3275                 return (-EIO);
3276         return partition;
3277 }
3278
3279
3280 /* Change the partition if necessary */
3281 static int switch_partition(struct scsi_tape *STp)
3282 {
3283         struct st_partstat *STps;
3284
3285         if (STp->partition == STp->new_partition)
3286                 return 0;
3287         STps = &(STp->ps[STp->new_partition]);
3288         if (!STps->last_block_valid)
3289                 STps->last_block_visited = 0;
3290         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3291 }
3292 \f
3293 /* Functions for reading and writing the medium partition mode page. */
3294
3295 #define PART_PAGE   0x11
3296 #define PART_PAGE_FIXED_LENGTH 8
3297
3298 #define PP_OFF_MAX_ADD_PARTS   2
3299 #define PP_OFF_NBR_ADD_PARTS   3
3300 #define PP_OFF_FLAGS           4
3301 #define PP_OFF_PART_UNITS      6
3302 #define PP_OFF_RESERVED        7
3303
3304 #define PP_BIT_IDP             0x20
3305 #define PP_BIT_FDP             0x80
3306 #define PP_MSK_PSUM_MB         0x10
3307 #define PP_MSK_PSUM_UNITS      0x18
3308 #define PP_MSK_POFM            0x04
3309
3310 /* Get the number of partitions on the tape. As a side effect reads the
3311    mode page into the tape buffer. */
3312 static int nbr_partitions(struct scsi_tape *STp)
3313 {
3314         int result;
3315
3316         if (STp->ready != ST_READY)
3317                 return (-EIO);
3318
3319         result = read_mode_page(STp, PART_PAGE, 1);
3320
3321         if (result) {
3322                 DEBC_printk(STp, "Can't read medium partition page.\n");
3323                 result = (-EIO);
3324         } else {
3325                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3326                                               PP_OFF_NBR_ADD_PARTS] + 1;
3327                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3328         }
3329
3330         return result;
3331 }
3332
3333
3334 static int format_medium(struct scsi_tape *STp, int format)
3335 {
3336         int result = 0;
3337         int timeout = STp->long_timeout;
3338         unsigned char scmd[MAX_COMMAND_SIZE];
3339         struct st_request *SRpnt;
3340
3341         memset(scmd, 0, MAX_COMMAND_SIZE);
3342         scmd[0] = FORMAT_UNIT;
3343         scmd[2] = format;
3344         if (STp->immediate) {
3345                 scmd[1] |= 1;           /* Don't wait for completion */
3346                 timeout = STp->device->request_queue->rq_timeout;
3347         }
3348         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3349         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3350                            timeout, MAX_RETRIES, 1);
3351         if (!SRpnt)
3352                 result = STp->buffer->syscall_result;
3353         return result;
3354 }
3355
3356
3357 /* Partition the tape into two partitions if size > 0 or one partition if
3358    size == 0.
3359
3360    The block descriptors are read and written because Sony SDT-7000 does not
3361    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3362
3363    My HP C1533A drive returns only one partition size field. This is used to
3364    set the size of partition 1. There is no size field for the default partition.
3365    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3366    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3367    The following algorithm is used to accommodate both drives: if the number of
3368    partition size fields is greater than the maximum number of additional partitions
3369    in the mode page, the second field is used. Otherwise the first field is used.
3370
3371    For Seagate DDS drives the page length must be 8 when no partitions is defined
3372    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3373    is acceptable also to some other old drives and enforced if the first partition
3374    size field is used for the first additional partition size.
3375
3376    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3377  */
3378 static int partition_tape(struct scsi_tape *STp, int size)
3379 {
3380         int result;
3381         int target_partition;
3382         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3383         int pgo, psd_cnt, psdo;
3384         int psum = PP_MSK_PSUM_MB, units = 0;
3385         unsigned char *bp;
3386
3387         result = read_mode_page(STp, PART_PAGE, 0);
3388         if (result) {
3389                 DEBC_printk(STp, "Can't read partition mode page.\n");
3390                 return result;
3391         }
3392         target_partition = 1;
3393         if (size < 0) {
3394                 target_partition = 0;
3395                 size = -size;
3396         }
3397
3398         /* The mode page is in the buffer. Let's modify it and write it. */
3399         bp = (STp->buffer)->b_data;
3400         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3401         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3402                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3403
3404         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3405
3406         if (scsi3) {
3407                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3408                 if (needs_format && size == 0) {
3409                         /* No need to write the mode page when clearing
3410                          *  partitioning
3411                          */
3412                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3413                         result = format_medium(STp, 0);
3414                         goto out;
3415                 }
3416                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3417                         psd_cnt = 2;
3418                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3419                         /* Use units scaling for large partitions if the device
3420                          * suggests it and no precision lost. Required for IBM
3421                          * TS1140/50 drives that don't support MB units.
3422                          */
3423                         if (size >= 1000 && (size % 1000) == 0) {
3424                                 size /= 1000;
3425                                 psum = PP_MSK_PSUM_UNITS;
3426                                 units = 9; /* GB */
3427                         }
3428                 }
3429                 /* Try it anyway if too large to specify in MB */
3430                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3431                         size /= 1000;
3432                         psum = PP_MSK_PSUM_UNITS;
3433                         units = 9;  /* GB */
3434                 }
3435         }
3436
3437         if (size >= 65535 ||  /* Does not fit into two bytes */
3438             (target_partition == 0 && psd_cnt < 2)) {
3439                 result = -EINVAL;
3440                 goto out;
3441         }
3442
3443         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3444         /* The second condition is for HP DDS which use only one partition size
3445          * descriptor
3446          */
3447         if (target_partition > 0 &&
3448             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3449              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3450                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3451                 psdo += 2;
3452         }
3453         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3454
3455         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3456                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3457                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3458
3459         if (size == 0) {
3460                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3461                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3462                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3463                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3464         } else {
3465                 bp[psdo] = (size >> 8) & 0xff;
3466                 bp[psdo + 1] = size & 0xff;
3467                 if (target_partition == 0)
3468                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3469                 bp[pgo + 3] = 1;
3470                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3471                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3472                 DEBC_printk(STp,
3473                             "Formatting tape with two partitions (%i = %d MB).\n",
3474                             target_partition, units > 0 ? size * 1000 : size);
3475         }
3476         bp[pgo + PP_OFF_PART_UNITS] = 0;
3477         bp[pgo + PP_OFF_RESERVED] = 0;
3478         if (size != 1 || units != 0) {
3479                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3480                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3481                 bp[pgo + PP_OFF_PART_UNITS] = units;
3482         } else
3483                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3484                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3485         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3486
3487         result = write_mode_page(STp, PART_PAGE, 1);
3488
3489         if (!result && needs_format)
3490                 result = format_medium(STp, 1);
3491
3492         if (result) {
3493                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3494                 result = (-EIO);
3495         }
3496
3497 out:
3498         return result;
3499 }
3500 \f
3501
3502
3503 /* The ioctl command */
3504 static long st_ioctl_common(struct file *file, unsigned int cmd_in, void __user *p)
3505 {
3506         int i, cmd_nr, cmd_type, bt;
3507         int retval = 0;
3508         unsigned int blk;
3509         struct scsi_tape *STp = file->private_data;
3510         struct st_modedef *STm;
3511         struct st_partstat *STps;
3512
3513         if (mutex_lock_interruptible(&STp->lock))
3514                 return -ERESTARTSYS;
3515
3516         DEB(
3517         if (debugging && !STp->in_use) {
3518                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3519                 retval = (-EIO);
3520                 goto out;
3521         } ) /* end DEB */
3522
3523         STm = &(STp->modes[STp->current_mode]);
3524         STps = &(STp->ps[STp->partition]);
3525
3526         /*
3527          * If we are in the middle of error recovery, don't let anyone
3528          * else try and use this device.  Also, if error recovery fails, it
3529          * may try and take the device offline, in which case all further
3530          * access to the device is prohibited.
3531          */
3532         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3533                         file->f_flags & O_NDELAY);
3534         if (retval)
3535                 goto out;
3536
3537         cmd_type = _IOC_TYPE(cmd_in);
3538         cmd_nr = _IOC_NR(cmd_in);
3539
3540         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3541                 struct mtop mtc;
3542
3543                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3544                         retval = (-EINVAL);
3545                         goto out;
3546                 }
3547
3548                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3549                 if (i) {
3550                         retval = (-EFAULT);
3551                         goto out;
3552                 }
3553
3554                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3555                         st_printk(KERN_WARNING, STp,
3556                                   "MTSETDRVBUFFER only allowed for root.\n");
3557                         retval = (-EPERM);
3558                         goto out;
3559                 }
3560                 if (!STm->defined &&
3561                     (mtc.mt_op != MTSETDRVBUFFER &&
3562                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3563                         retval = (-ENXIO);
3564                         goto out;
3565                 }
3566
3567                 if (!STp->pos_unknown) {
3568
3569                         if (STps->eof == ST_FM_HIT) {
3570                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3571                                     mtc.mt_op == MTEOM) {
3572                                         mtc.mt_count -= 1;
3573                                         if (STps->drv_file >= 0)
3574                                                 STps->drv_file += 1;
3575                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3576                                         mtc.mt_count += 1;
3577                                         if (STps->drv_file >= 0)
3578                                                 STps->drv_file += 1;
3579                                 }
3580                         }
3581
3582                         if (mtc.mt_op == MTSEEK) {
3583                                 /* Old position must be restored if partition will be
3584                                    changed */
3585                                 i = !STp->can_partitions ||
3586                                     (STp->new_partition != STp->partition);
3587                         } else {
3588                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3589                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3590                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3591                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3592                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3593                                     mtc.mt_op == MTCOMPRESSION;
3594                         }
3595                         i = flush_buffer(STp, i);
3596                         if (i < 0) {
3597                                 retval = i;
3598                                 goto out;
3599                         }
3600                         if (STps->rw == ST_WRITING &&
3601                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3602                              mtc.mt_op == MTSEEK ||
3603                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3604                                 i = st_int_ioctl(STp, MTWEOF, 1);
3605                                 if (i < 0) {
3606                                         retval = i;
3607                                         goto out;
3608                                 }
3609                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3610                                         mtc.mt_count++;
3611                                 STps->rw = ST_IDLE;
3612                              }
3613
3614                 } else {
3615                         /*
3616                          * If there was a bus reset, block further access
3617                          * to this device.  If the user wants to rewind the tape,
3618                          * then reset the flag and allow access again.
3619                          */
3620                         if (mtc.mt_op != MTREW &&
3621                             mtc.mt_op != MTOFFL &&
3622                             mtc.mt_op != MTRETEN &&
3623                             mtc.mt_op != MTERASE &&
3624                             mtc.mt_op != MTSEEK &&
3625                             mtc.mt_op != MTEOM) {
3626                                 retval = (-EIO);
3627                                 goto out;
3628                         }
3629                         reset_state(STp);
3630                         /* remove this when the midlevel properly clears was_reset */
3631                         STp->device->was_reset = 0;
3632                 }
3633
3634                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3635                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3636                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3637                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3638
3639                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3640                         do_door_lock(STp, 0);   /* Ignore result! */
3641
3642                 if (mtc.mt_op == MTSETDRVBUFFER &&
3643                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3644                         retval = st_set_options(STp, mtc.mt_count);
3645                         goto out;
3646                 }
3647
3648                 if (mtc.mt_op == MTSETPART) {
3649                         if (!STp->can_partitions ||
3650                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3651                                 retval = (-EINVAL);
3652                                 goto out;
3653                         }
3654                         if (mtc.mt_count >= STp->nbr_partitions &&
3655                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3656                                 retval = (-EIO);
3657                                 goto out;
3658                         }
3659                         if (mtc.mt_count >= STp->nbr_partitions) {
3660                                 retval = (-EINVAL);
3661                                 goto out;
3662                         }
3663                         STp->new_partition = mtc.mt_count;
3664                         retval = 0;
3665                         goto out;
3666                 }
3667
3668                 if (mtc.mt_op == MTMKPART) {
3669                         if (!STp->can_partitions) {
3670                                 retval = (-EINVAL);
3671                                 goto out;
3672                         }
3673                         i = do_load_unload(STp, file, 1);
3674                         if (i < 0) {
3675                                 retval = i;
3676                                 goto out;
3677                         }
3678                         i = partition_tape(STp, mtc.mt_count);
3679                         if (i < 0) {
3680                                 retval = i;
3681                                 goto out;
3682                         }
3683                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3684                                 STp->ps[i].rw = ST_IDLE;
3685                                 STp->ps[i].at_sm = 0;
3686                                 STp->ps[i].last_block_valid = 0;
3687                         }
3688                         STp->partition = STp->new_partition = 0;
3689                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3690                         STps->drv_block = STps->drv_file = 0;
3691                         retval = 0;
3692                         goto out;
3693                 }
3694
3695                 if (mtc.mt_op == MTSEEK) {
3696                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3697                         if (!STp->can_partitions)
3698                                 STp->ps[0].rw = ST_IDLE;
3699                         retval = i;
3700                         goto out;
3701                 }
3702
3703                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3704                         retval = do_load_unload(STp, file, 0);
3705                         goto out;
3706                 }
3707
3708                 if (mtc.mt_op == MTLOAD) {
3709                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3710                         goto out;
3711                 }
3712
3713                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3714                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3715                         goto out;
3716                 }
3717
3718                 if (STp->can_partitions && STp->ready == ST_READY &&
3719                     (i = switch_partition(STp)) < 0) {
3720                         retval = i;
3721                         goto out;
3722                 }
3723
3724                 if (mtc.mt_op == MTCOMPRESSION)
3725                         retval = st_compression(STp, (mtc.mt_count & 1));
3726                 else
3727                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3728                 goto out;
3729         }
3730         if (!STm->defined) {
3731                 retval = (-ENXIO);
3732                 goto out;
3733         }
3734
3735         if ((i = flush_buffer(STp, 0)) < 0) {
3736                 retval = i;
3737                 goto out;
3738         }
3739         if (STp->can_partitions &&
3740             (i = switch_partition(STp)) < 0) {
3741                 retval = i;
3742                 goto out;
3743         }
3744
3745         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3746                 struct mtget mt_status;
3747
3748                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3749                          retval = (-EINVAL);
3750                          goto out;
3751                 }
3752
3753                 mt_status.mt_type = STp->tape_type;
3754                 mt_status.mt_dsreg =
3755                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3756                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3757                 mt_status.mt_blkno = STps->drv_block;
3758                 mt_status.mt_fileno = STps->drv_file;
3759                 if (STp->block_size != 0) {
3760                         if (STps->rw == ST_WRITING)
3761                                 mt_status.mt_blkno +=
3762                                     (STp->buffer)->buffer_bytes / STp->block_size;
3763                         else if (STps->rw == ST_READING)
3764                                 mt_status.mt_blkno -=
3765                                         ((STp->buffer)->buffer_bytes +
3766                                          STp->block_size - 1) / STp->block_size;
3767                 }
3768
3769                 mt_status.mt_gstat = 0;
3770                 if (STp->drv_write_prot)
3771                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3772                 if (mt_status.mt_blkno == 0) {
3773                         if (mt_status.mt_fileno == 0)
3774                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3775                         else
3776                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3777                 }
3778                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3779                 mt_status.mt_resid = STp->partition;
3780                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3781                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3782                 else if (STps->eof >= ST_EOM_OK)
3783                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3784                 if (STp->density == 1)
3785                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3786                 else if (STp->density == 2)
3787                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3788                 else if (STp->density == 3)
3789                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3790                 if (STp->ready == ST_READY)
3791                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3792                 if (STp->ready == ST_NO_TAPE)
3793                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3794                 if (STps->at_sm)
3795                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3796                 if (STm->do_async_writes ||
3797                     (STm->do_buffer_writes && STp->block_size != 0) ||
3798                     STp->drv_buffer != 0)
3799                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3800                 if (STp->cleaning_req)
3801                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3802
3803                 retval = put_user_mtget(p, &mt_status);
3804                 if (retval)
3805                         goto out;
3806
3807                 STp->recover_reg = 0;           /* Clear after read */
3808                 goto out;
3809         }                       /* End of MTIOCGET */
3810         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3811                 struct mtpos mt_pos;
3812                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3813                          retval = (-EINVAL);
3814                          goto out;
3815                 }
3816                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3817                         retval = i;
3818                         goto out;
3819                 }
3820                 mt_pos.mt_blkno = blk;
3821                 retval = put_user_mtpos(p, &mt_pos);
3822                 goto out;
3823         }
3824         mutex_unlock(&STp->lock);
3825         switch (cmd_in) {
3826                 case SCSI_IOCTL_STOP_UNIT:
3827                         /* unload */
3828                         retval = scsi_ioctl(STp->device, cmd_in, p);
3829                         if (!retval) {
3830                                 STp->rew_at_close = 0;
3831                                 STp->ready = ST_NO_TAPE;
3832                         }
3833                         return retval;
3834
3835                 case SCSI_IOCTL_GET_IDLUN:
3836                 case SCSI_IOCTL_GET_BUS_NUMBER:
3837                         break;
3838
3839                 default:
3840                         if ((cmd_in == SG_IO ||
3841                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3842                              cmd_in == CDROM_SEND_PACKET) &&
3843                             !capable(CAP_SYS_RAWIO))
3844                                 i = -EPERM;
3845                         else
3846                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3847                                                    file->f_mode, cmd_in, p);
3848                         if (i != -ENOTTY)
3849                                 return i;
3850                         break;
3851         }
3852         return -ENOTTY;
3853
3854  out:
3855         mutex_unlock(&STp->lock);
3856         return retval;
3857 }
3858
3859 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3860 {
3861         void __user *p = (void __user *)arg;
3862         struct scsi_tape *STp = file->private_data;
3863         int ret;
3864
3865         ret = st_ioctl_common(file, cmd_in, p);
3866         if (ret != -ENOTTY)
3867                 return ret;
3868
3869         return scsi_ioctl(STp->device, cmd_in, p);
3870 }
3871
3872 #ifdef CONFIG_COMPAT
3873 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3874 {
3875         void __user *p = compat_ptr(arg);
3876         struct scsi_tape *STp = file->private_data;
3877         int ret;
3878
3879         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3880         switch (cmd_in) {
3881         case MTIOCPOS32:
3882                 return st_ioctl_common(file, MTIOCPOS, p);
3883         case MTIOCGET32:
3884                 return st_ioctl_common(file, MTIOCGET, p);
3885         }
3886
3887         ret = st_ioctl_common(file, cmd_in, p);
3888         if (ret != -ENOTTY)
3889                 return ret;
3890
3891         return scsi_compat_ioctl(STp->device, cmd_in, p);
3892 }
3893 #endif
3894
3895 \f
3896
3897 /* Try to allocate a new tape buffer. Calling function must not hold
3898    dev_arr_lock. */
3899 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3900 {
3901         struct st_buffer *tb;
3902
3903         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3904         if (!tb) {
3905                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3906                 return NULL;
3907         }
3908         tb->frp_segs = 0;
3909         tb->use_sg = max_sg;
3910         tb->dma = need_dma;
3911         tb->buffer_size = 0;
3912
3913         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3914                                      GFP_KERNEL);
3915         if (!tb->reserved_pages) {
3916                 kfree(tb);
3917                 return NULL;
3918         }
3919
3920         return tb;
3921 }
3922
3923
3924 /* Try to allocate enough space in the tape buffer */
3925 #define ST_MAX_ORDER 6
3926
3927 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3928 {
3929         int segs, max_segs, b_size, order, got;
3930         gfp_t priority;
3931
3932         if (new_size <= STbuffer->buffer_size)
3933                 return 1;
3934
3935         if (STbuffer->buffer_size <= PAGE_SIZE)
3936                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3937
3938         max_segs = STbuffer->use_sg;
3939
3940         priority = GFP_KERNEL | __GFP_NOWARN;
3941         if (need_dma)
3942                 priority |= GFP_DMA;
3943
3944         if (STbuffer->cleared)
3945                 priority |= __GFP_ZERO;
3946
3947         if (STbuffer->frp_segs) {
3948                 order = STbuffer->reserved_page_order;
3949                 b_size = PAGE_SIZE << order;
3950         } else {
3951                 for (b_size = PAGE_SIZE, order = 0;
3952                      order < ST_MAX_ORDER &&
3953                              max_segs * (PAGE_SIZE << order) < new_size;
3954                      order++, b_size *= 2)
3955                         ;  /* empty */
3956                 STbuffer->reserved_page_order = order;
3957         }
3958         if (max_segs * (PAGE_SIZE << order) < new_size) {
3959                 if (order == ST_MAX_ORDER)
3960                         return 0;
3961                 normalize_buffer(STbuffer);
3962                 return enlarge_buffer(STbuffer, new_size, need_dma);
3963         }
3964
3965         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3966              segs < max_segs && got < new_size;) {
3967                 struct page *page;
3968
3969                 page = alloc_pages(priority, order);
3970                 if (!page) {
3971                         DEB(STbuffer->buffer_size = got);
3972                         normalize_buffer(STbuffer);
3973                         return 0;
3974                 }
3975
3976                 STbuffer->frp_segs += 1;
3977                 got += b_size;
3978                 STbuffer->buffer_size = got;
3979                 STbuffer->reserved_pages[segs] = page;
3980                 segs++;
3981         }
3982         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3983
3984         return 1;
3985 }
3986
3987
3988 /* Make sure that no data from previous user is in the internal buffer */
3989 static void clear_buffer(struct st_buffer * st_bp)
3990 {
3991         int i;
3992
3993         for (i=0; i < st_bp->frp_segs; i++)
3994                 memset(page_address(st_bp->reserved_pages[i]), 0,
3995                        PAGE_SIZE << st_bp->reserved_page_order);
3996         st_bp->cleared = 1;
3997 }
3998
3999
4000 /* Release the extra buffer */
4001 static void normalize_buffer(struct st_buffer * STbuffer)
4002 {
4003         int i, order = STbuffer->reserved_page_order;
4004
4005         for (i = 0; i < STbuffer->frp_segs; i++) {
4006                 __free_pages(STbuffer->reserved_pages[i], order);
4007                 STbuffer->buffer_size -= (PAGE_SIZE << order);
4008         }
4009         STbuffer->frp_segs = 0;
4010         STbuffer->sg_segs = 0;
4011         STbuffer->reserved_page_order = 0;
4012         STbuffer->map_data.offset = 0;
4013 }
4014
4015
4016 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
4017    negative error code. */
4018 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
4019 {
4020         int i, cnt, res, offset;
4021         int length = PAGE_SIZE << st_bp->reserved_page_order;
4022
4023         for (i = 0, offset = st_bp->buffer_bytes;
4024              i < st_bp->frp_segs && offset >= length; i++)
4025                 offset -= length;
4026         if (i == st_bp->frp_segs) {     /* Should never happen */
4027                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4028                 return (-EIO);
4029         }
4030         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4031                 struct page *page = st_bp->reserved_pages[i];
4032                 cnt = length - offset < do_count ? length - offset : do_count;
4033                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4034                 if (res)
4035                         return (-EFAULT);
4036                 do_count -= cnt;
4037                 st_bp->buffer_bytes += cnt;
4038                 ubp += cnt;
4039                 offset = 0;
4040         }
4041         if (do_count) /* Should never happen */
4042                 return (-EIO);
4043
4044         return 0;
4045 }
4046
4047
4048 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4049    negative error code. */
4050 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4051 {
4052         int i, cnt, res, offset;
4053         int length = PAGE_SIZE << st_bp->reserved_page_order;
4054
4055         for (i = 0, offset = st_bp->read_pointer;
4056              i < st_bp->frp_segs && offset >= length; i++)
4057                 offset -= length;
4058         if (i == st_bp->frp_segs) {     /* Should never happen */
4059                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4060                 return (-EIO);
4061         }
4062         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4063                 struct page *page = st_bp->reserved_pages[i];
4064                 cnt = length - offset < do_count ? length - offset : do_count;
4065                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4066                 if (res)
4067                         return (-EFAULT);
4068                 do_count -= cnt;
4069                 st_bp->buffer_bytes -= cnt;
4070                 st_bp->read_pointer += cnt;
4071                 ubp += cnt;
4072                 offset = 0;
4073         }
4074         if (do_count) /* Should never happen */
4075                 return (-EIO);
4076
4077         return 0;
4078 }
4079
4080
4081 /* Move data towards start of buffer */
4082 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4083 {
4084         int src_seg, dst_seg, src_offset = 0, dst_offset;
4085         int count, total;
4086         int length = PAGE_SIZE << st_bp->reserved_page_order;
4087
4088         if (offset == 0)
4089                 return;
4090
4091         total=st_bp->buffer_bytes - offset;
4092         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4093                 src_offset = offset;
4094                 if (src_offset < length)
4095                         break;
4096                 offset -= length;
4097         }
4098
4099         st_bp->buffer_bytes = st_bp->read_pointer = total;
4100         for (dst_seg=dst_offset=0; total > 0; ) {
4101                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4102                 struct page *spage = st_bp->reserved_pages[src_seg];
4103
4104                 count = min(length - dst_offset, length - src_offset);
4105                 memmove(page_address(dpage) + dst_offset,
4106                         page_address(spage) + src_offset, count);
4107                 src_offset += count;
4108                 if (src_offset >= length) {
4109                         src_seg++;
4110                         src_offset = 0;
4111                 }
4112                 dst_offset += count;
4113                 if (dst_offset >= length) {
4114                         dst_seg++;
4115                         dst_offset = 0;
4116                 }
4117                 total -= count;
4118         }
4119 }
4120
4121 /* Validate the options from command line or module parameters */
4122 static void validate_options(void)
4123 {
4124         if (buffer_kbs > 0)
4125                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4126         if (max_sg_segs >= ST_FIRST_SG)
4127                 st_max_sg_segs = max_sg_segs;
4128 }
4129
4130 #ifndef MODULE
4131 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4132  */
4133 static int __init st_setup(char *str)
4134 {
4135         int i, len, ints[5];
4136         char *stp;
4137
4138         stp = get_options(str, ARRAY_SIZE(ints), ints);
4139
4140         if (ints[0] > 0) {
4141                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4142                         if (parms[i].val)
4143                                 *parms[i].val = ints[i + 1];
4144         } else {
4145                 while (stp != NULL) {
4146                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4147                                 len = strlen(parms[i].name);
4148                                 if (!strncmp(stp, parms[i].name, len) &&
4149                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4150                                         if (parms[i].val)
4151                                                 *parms[i].val =
4152                                                         simple_strtoul(stp + len + 1, NULL, 0);
4153                                         else
4154                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4155                                                        parms[i].name);
4156                                         break;
4157                                 }
4158                         }
4159                         if (i >= ARRAY_SIZE(parms))
4160                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4161                                         stp);
4162                         stp = strchr(stp, ',');
4163                         if (stp)
4164                                 stp++;
4165                 }
4166         }
4167
4168         validate_options();
4169
4170         return 1;
4171 }
4172
4173 __setup("st=", st_setup);
4174
4175 #endif
4176
4177 static const struct file_operations st_fops =
4178 {
4179         .owner =        THIS_MODULE,
4180         .read =         st_read,
4181         .write =        st_write,
4182         .unlocked_ioctl = st_ioctl,
4183 #ifdef CONFIG_COMPAT
4184         .compat_ioctl = st_compat_ioctl,
4185 #endif
4186         .open =         st_open,
4187         .flush =        st_flush,
4188         .release =      st_release,
4189         .llseek =       noop_llseek,
4190 };
4191
4192 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4193 {
4194         int i, error;
4195         dev_t cdev_devno;
4196         struct cdev *cdev;
4197         struct device *dev;
4198         struct st_modedef *STm = &(tape->modes[mode]);
4199         char name[10];
4200         int dev_num = tape->index;
4201
4202         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4203
4204         cdev = cdev_alloc();
4205         if (!cdev) {
4206                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4207                 error = -ENOMEM;
4208                 goto out;
4209         }
4210         cdev->owner = THIS_MODULE;
4211         cdev->ops = &st_fops;
4212         STm->cdevs[rew] = cdev;
4213
4214         error = cdev_add(cdev, cdev_devno, 1);
4215         if (error) {
4216                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4217                        rew ? "non" : "auto", mode);
4218                 pr_err("st%d: Device not attached.\n", dev_num);
4219                 goto out_free;
4220         }
4221
4222         i = mode << (4 - ST_NBR_MODE_BITS);
4223         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4224                  tape->disk->disk_name, st_formats[i]);
4225
4226         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4227                             cdev_devno, &tape->modes[mode], "%s", name);
4228         if (IS_ERR(dev)) {
4229                 pr_err("st%d: device_create failed\n", dev_num);
4230                 error = PTR_ERR(dev);
4231                 goto out_free;
4232         }
4233
4234         STm->devs[rew] = dev;
4235
4236         return 0;
4237 out_free:
4238         cdev_del(STm->cdevs[rew]);
4239 out:
4240         STm->cdevs[rew] = NULL;
4241         STm->devs[rew] = NULL;
4242         return error;
4243 }
4244
4245 static int create_cdevs(struct scsi_tape *tape)
4246 {
4247         int mode, error;
4248         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4249                 error = create_one_cdev(tape, mode, 0);
4250                 if (error)
4251                         return error;
4252                 error = create_one_cdev(tape, mode, 1);
4253                 if (error)
4254                         return error;
4255         }
4256
4257         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4258                                  &tape->modes[0].devs[0]->kobj, "tape");
4259 }
4260
4261 static void remove_cdevs(struct scsi_tape *tape)
4262 {
4263         int mode, rew;
4264         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4265         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4266                 struct st_modedef *STm = &(tape->modes[mode]);
4267                 for (rew = 0; rew < 2; rew++) {
4268                         if (STm->cdevs[rew])
4269                                 cdev_del(STm->cdevs[rew]);
4270                         if (STm->devs[rew])
4271                                 device_unregister(STm->devs[rew]);
4272                 }
4273         }
4274 }
4275
4276 static int st_probe(struct device *dev)
4277 {
4278         struct scsi_device *SDp = to_scsi_device(dev);
4279         struct gendisk *disk = NULL;
4280         struct scsi_tape *tpnt = NULL;
4281         struct st_modedef *STm;
4282         struct st_partstat *STps;
4283         struct st_buffer *buffer;
4284         int i, error;
4285         char *stp;
4286
4287         if (SDp->type != TYPE_TAPE)
4288                 return -ENODEV;
4289         if ((stp = st_incompatible(SDp))) {
4290                 sdev_printk(KERN_INFO, SDp,
4291                             "OnStream tapes are no longer supported;\n");
4292                 sdev_printk(KERN_INFO, SDp,
4293                             "please mail to linux-scsi@vger.kernel.org.\n");
4294                 return -ENODEV;
4295         }
4296
4297         scsi_autopm_get_device(SDp);
4298         i = queue_max_segments(SDp->request_queue);
4299         if (st_max_sg_segs < i)
4300                 i = st_max_sg_segs;
4301         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4302         if (buffer == NULL) {
4303                 sdev_printk(KERN_ERR, SDp,
4304                             "st: Can't allocate new tape buffer. "
4305                             "Device not attached.\n");
4306                 goto out;
4307         }
4308
4309         disk = alloc_disk(1);
4310         if (!disk) {
4311                 sdev_printk(KERN_ERR, SDp,
4312                             "st: out of memory. Device not attached.\n");
4313                 goto out_buffer_free;
4314         }
4315
4316         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4317         if (tpnt == NULL) {
4318                 sdev_printk(KERN_ERR, SDp,
4319                             "st: Can't allocate device descriptor.\n");
4320                 goto out_put_disk;
4321         }
4322         kref_init(&tpnt->kref);
4323         tpnt->disk = disk;
4324         disk->private_data = &tpnt->driver;
4325         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4326          * take queue reference that release_disk() expects. */
4327         if (!blk_get_queue(SDp->request_queue))
4328                 goto out_put_disk;
4329         disk->queue = SDp->request_queue;
4330         tpnt->driver = &st_template;
4331
4332         tpnt->device = SDp;
4333         if (SDp->scsi_level <= 2)
4334                 tpnt->tape_type = MT_ISSCSI1;
4335         else
4336                 tpnt->tape_type = MT_ISSCSI2;
4337
4338         tpnt->buffer = buffer;
4339         tpnt->buffer->last_SRpnt = NULL;
4340
4341         tpnt->inited = 0;
4342         tpnt->dirty = 0;
4343         tpnt->in_use = 0;
4344         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4345         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4346         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4347         tpnt->density = 0;
4348         tpnt->do_auto_lock = ST_AUTO_LOCK;
4349         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4350         tpnt->can_partitions = 0;
4351         tpnt->two_fm = ST_TWO_FM;
4352         tpnt->fast_mteom = ST_FAST_MTEOM;
4353         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4354         tpnt->sili = ST_SILI;
4355         tpnt->immediate = ST_NOWAIT;
4356         tpnt->immediate_filemark = 0;
4357         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4358         tpnt->partition = 0;
4359         tpnt->new_partition = 0;
4360         tpnt->nbr_partitions = 0;
4361         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4362         tpnt->long_timeout = ST_LONG_TIMEOUT;
4363         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4364
4365         for (i = 0; i < ST_NBR_MODES; i++) {
4366                 STm = &(tpnt->modes[i]);
4367                 STm->defined = 0;
4368                 STm->sysv = ST_SYSV;
4369                 STm->defaults_for_writes = 0;
4370                 STm->do_async_writes = ST_ASYNC_WRITES;
4371                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4372                 STm->do_read_ahead = ST_READ_AHEAD;
4373                 STm->default_compression = ST_DONT_TOUCH;
4374                 STm->default_blksize = (-1);    /* No forced size */
4375                 STm->default_density = (-1);    /* No forced density */
4376                 STm->tape = tpnt;
4377         }
4378
4379         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4380                 STps = &(tpnt->ps[i]);
4381                 STps->rw = ST_IDLE;
4382                 STps->eof = ST_NOEOF;
4383                 STps->at_sm = 0;
4384                 STps->last_block_valid = 0;
4385                 STps->drv_block = (-1);
4386                 STps->drv_file = (-1);
4387         }
4388
4389         tpnt->current_mode = 0;
4390         tpnt->modes[0].defined = 1;
4391
4392         tpnt->density_changed = tpnt->compression_changed =
4393             tpnt->blksize_changed = 0;
4394         mutex_init(&tpnt->lock);
4395
4396         idr_preload(GFP_KERNEL);
4397         spin_lock(&st_index_lock);
4398         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4399         spin_unlock(&st_index_lock);
4400         idr_preload_end();
4401         if (error < 0) {
4402                 pr_warn("st: idr allocation failed: %d\n", error);
4403                 goto out_put_queue;
4404         }
4405         tpnt->index = error;
4406         sprintf(disk->disk_name, "st%d", tpnt->index);
4407         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4408         if (tpnt->stats == NULL) {
4409                 sdev_printk(KERN_ERR, SDp,
4410                             "st: Can't allocate statistics.\n");
4411                 goto out_idr_remove;
4412         }
4413
4414         dev_set_drvdata(dev, tpnt);
4415
4416
4417         error = create_cdevs(tpnt);
4418         if (error)
4419                 goto out_remove_devs;
4420         scsi_autopm_put_device(SDp);
4421
4422         sdev_printk(KERN_NOTICE, SDp,
4423                     "Attached scsi tape %s\n", tape_name(tpnt));
4424         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4425                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4426                     queue_dma_alignment(SDp->request_queue) + 1);
4427
4428         return 0;
4429
4430 out_remove_devs:
4431         remove_cdevs(tpnt);
4432         kfree(tpnt->stats);
4433 out_idr_remove:
4434         spin_lock(&st_index_lock);
4435         idr_remove(&st_index_idr, tpnt->index);
4436         spin_unlock(&st_index_lock);
4437 out_put_queue:
4438         blk_put_queue(disk->queue);
4439 out_put_disk:
4440         put_disk(disk);
4441         kfree(tpnt);
4442 out_buffer_free:
4443         kfree(buffer);
4444 out:
4445         scsi_autopm_put_device(SDp);
4446         return -ENODEV;
4447 };
4448
4449
4450 static int st_remove(struct device *dev)
4451 {
4452         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4453         int index = tpnt->index;
4454
4455         scsi_autopm_get_device(to_scsi_device(dev));
4456         remove_cdevs(tpnt);
4457
4458         mutex_lock(&st_ref_mutex);
4459         kref_put(&tpnt->kref, scsi_tape_release);
4460         mutex_unlock(&st_ref_mutex);
4461         spin_lock(&st_index_lock);
4462         idr_remove(&st_index_idr, index);
4463         spin_unlock(&st_index_lock);
4464         return 0;
4465 }
4466
4467 /**
4468  *      scsi_tape_release - Called to free the Scsi_Tape structure
4469  *      @kref: pointer to embedded kref
4470  *
4471  *      st_ref_mutex must be held entering this routine.  Because it is
4472  *      called on last put, you should always use the scsi_tape_get()
4473  *      scsi_tape_put() helpers which manipulate the semaphore directly
4474  *      and never do a direct kref_put().
4475  **/
4476 static void scsi_tape_release(struct kref *kref)
4477 {
4478         struct scsi_tape *tpnt = to_scsi_tape(kref);
4479         struct gendisk *disk = tpnt->disk;
4480
4481         tpnt->device = NULL;
4482
4483         if (tpnt->buffer) {
4484                 normalize_buffer(tpnt->buffer);
4485                 kfree(tpnt->buffer->reserved_pages);
4486                 kfree(tpnt->buffer);
4487         }
4488
4489         disk->private_data = NULL;
4490         put_disk(disk);
4491         kfree(tpnt->stats);
4492         kfree(tpnt);
4493         return;
4494 }
4495
4496 static struct class st_sysfs_class = {
4497         .name = "scsi_tape",
4498         .dev_groups = st_dev_groups,
4499 };
4500
4501 static int __init init_st(void)
4502 {
4503         int err;
4504
4505         validate_options();
4506
4507         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4508                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4509
4510         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4511         if (debugging) {
4512                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4513                         debugging);
4514         }
4515
4516         err = class_register(&st_sysfs_class);
4517         if (err) {
4518                 pr_err("Unable register sysfs class for SCSI tapes\n");
4519                 return err;
4520         }
4521
4522         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4523                                      ST_MAX_TAPE_ENTRIES, "st");
4524         if (err) {
4525                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4526                        SCSI_TAPE_MAJOR);
4527                 goto err_class;
4528         }
4529
4530         err = scsi_register_driver(&st_template.gendrv);
4531         if (err)
4532                 goto err_chrdev;
4533
4534         return 0;
4535
4536 err_chrdev:
4537         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4538                                  ST_MAX_TAPE_ENTRIES);
4539 err_class:
4540         class_unregister(&st_sysfs_class);
4541         return err;
4542 }
4543
4544 static void __exit exit_st(void)
4545 {
4546         scsi_unregister_driver(&st_template.gendrv);
4547         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4548                                  ST_MAX_TAPE_ENTRIES);
4549         class_unregister(&st_sysfs_class);
4550         idr_destroy(&st_index_idr);
4551         printk(KERN_INFO "st: Unloaded.\n");
4552 }
4553
4554 module_init(init_st);
4555 module_exit(exit_st);
4556
4557
4558 /* The sysfs driver interface. Read-only at the moment */
4559 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4560 {
4561         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4562 }
4563 static DRIVER_ATTR_RO(try_direct_io);
4564
4565 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4566 {
4567         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4568 }
4569 static DRIVER_ATTR_RO(fixed_buffer_size);
4570
4571 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4572 {
4573         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4574 }
4575 static DRIVER_ATTR_RO(max_sg_segs);
4576
4577 static ssize_t version_show(struct device_driver *ddd, char *buf)
4578 {
4579         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4580 }
4581 static DRIVER_ATTR_RO(version);
4582
4583 #if DEBUG
4584 static ssize_t debug_flag_store(struct device_driver *ddp,
4585         const char *buf, size_t count)
4586 {
4587 /* We only care what the first byte of the data is the rest is unused.
4588  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4589  * other values have -EINVAL returned if they are passed in.
4590  */
4591         if (count > 0) {
4592                 if (buf[0] == '0') {
4593                         debugging = NO_DEBUG;
4594                         return count;
4595                 } else if (buf[0] == '1') {
4596                         debugging = 1;
4597                         return count;
4598                 }
4599         }
4600         return -EINVAL;
4601 }
4602
4603 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4604 {
4605         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4606 }
4607 static DRIVER_ATTR_RW(debug_flag);
4608 #endif
4609
4610 static struct attribute *st_drv_attrs[] = {
4611         &driver_attr_try_direct_io.attr,
4612         &driver_attr_fixed_buffer_size.attr,
4613         &driver_attr_max_sg_segs.attr,
4614         &driver_attr_version.attr,
4615 #if DEBUG
4616         &driver_attr_debug_flag.attr,
4617 #endif
4618         NULL,
4619 };
4620 ATTRIBUTE_GROUPS(st_drv);
4621
4622 /* The sysfs simple class interface */
4623 static ssize_t
4624 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4625 {
4626         struct st_modedef *STm = dev_get_drvdata(dev);
4627         ssize_t l = 0;
4628
4629         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4630         return l;
4631 }
4632 static DEVICE_ATTR_RO(defined);
4633
4634 static ssize_t
4635 default_blksize_show(struct device *dev, struct device_attribute *attr,
4636                      char *buf)
4637 {
4638         struct st_modedef *STm = dev_get_drvdata(dev);
4639         ssize_t l = 0;
4640
4641         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4642         return l;
4643 }
4644 static DEVICE_ATTR_RO(default_blksize);
4645
4646 static ssize_t
4647 default_density_show(struct device *dev, struct device_attribute *attr,
4648                      char *buf)
4649 {
4650         struct st_modedef *STm = dev_get_drvdata(dev);
4651         ssize_t l = 0;
4652         char *fmt;
4653
4654         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4655         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4656         return l;
4657 }
4658 static DEVICE_ATTR_RO(default_density);
4659
4660 static ssize_t
4661 default_compression_show(struct device *dev, struct device_attribute *attr,
4662                          char *buf)
4663 {
4664         struct st_modedef *STm = dev_get_drvdata(dev);
4665         ssize_t l = 0;
4666
4667         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4668         return l;
4669 }
4670 static DEVICE_ATTR_RO(default_compression);
4671
4672 static ssize_t
4673 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4674 {
4675         struct st_modedef *STm = dev_get_drvdata(dev);
4676         struct scsi_tape *STp = STm->tape;
4677         int options;
4678         ssize_t l = 0;
4679
4680         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4681         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4682         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4683         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4684         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4685         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4686         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4687         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4688         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4689         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4690         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4691         options |= STm->sysv ? MT_ST_SYSV : 0;
4692         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4693         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4694         options |= STp->sili ? MT_ST_SILI : 0;
4695
4696         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4697         return l;
4698 }
4699 static DEVICE_ATTR_RO(options);
4700
4701 /* Support for tape stats */
4702
4703 /**
4704  * read_cnt_show - return read count - count of reads made from tape drive
4705  * @dev: struct device
4706  * @attr: attribute structure
4707  * @buf: buffer to return formatted data in
4708  */
4709 static ssize_t read_cnt_show(struct device *dev,
4710         struct device_attribute *attr, char *buf)
4711 {
4712         struct st_modedef *STm = dev_get_drvdata(dev);
4713
4714         return sprintf(buf, "%lld",
4715                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4716 }
4717 static DEVICE_ATTR_RO(read_cnt);
4718
4719 /**
4720  * read_byte_cnt_show - return read byte count - tape drives
4721  * may use blocks less than 512 bytes this gives the raw byte count of
4722  * of data read from the tape drive.
4723  * @dev: struct device
4724  * @attr: attribute structure
4725  * @buf: buffer to return formatted data in
4726  */
4727 static ssize_t read_byte_cnt_show(struct device *dev,
4728         struct device_attribute *attr, char *buf)
4729 {
4730         struct st_modedef *STm = dev_get_drvdata(dev);
4731
4732         return sprintf(buf, "%lld",
4733                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4734 }
4735 static DEVICE_ATTR_RO(read_byte_cnt);
4736
4737 /**
4738  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4739  * @dev: struct device
4740  * @attr: attribute structure
4741  * @buf: buffer to return formatted data in
4742  */
4743 static ssize_t read_ns_show(struct device *dev,
4744         struct device_attribute *attr, char *buf)
4745 {
4746         struct st_modedef *STm = dev_get_drvdata(dev);
4747
4748         return sprintf(buf, "%lld",
4749                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4750 }
4751 static DEVICE_ATTR_RO(read_ns);
4752
4753 /**
4754  * write_cnt_show - write count - number of user calls
4755  * to write(2) that have written data to tape.
4756  * @dev: struct device
4757  * @attr: attribute structure
4758  * @buf: buffer to return formatted data in
4759  */
4760 static ssize_t write_cnt_show(struct device *dev,
4761         struct device_attribute *attr, char *buf)
4762 {
4763         struct st_modedef *STm = dev_get_drvdata(dev);
4764
4765         return sprintf(buf, "%lld",
4766                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4767 }
4768 static DEVICE_ATTR_RO(write_cnt);
4769
4770 /**
4771  * write_byte_cnt_show - write byte count - raw count of
4772  * bytes written to tape.
4773  * @dev: struct device
4774  * @attr: attribute structure
4775  * @buf: buffer to return formatted data in
4776  */
4777 static ssize_t write_byte_cnt_show(struct device *dev,
4778         struct device_attribute *attr, char *buf)
4779 {
4780         struct st_modedef *STm = dev_get_drvdata(dev);
4781
4782         return sprintf(buf, "%lld",
4783                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4784 }
4785 static DEVICE_ATTR_RO(write_byte_cnt);
4786
4787 /**
4788  * write_ns_show - write ns - number of nanoseconds waiting on write
4789  * requests to complete.
4790  * @dev: struct device
4791  * @attr: attribute structure
4792  * @buf: buffer to return formatted data in
4793  */
4794 static ssize_t write_ns_show(struct device *dev,
4795         struct device_attribute *attr, char *buf)
4796 {
4797         struct st_modedef *STm = dev_get_drvdata(dev);
4798
4799         return sprintf(buf, "%lld",
4800                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4801 }
4802 static DEVICE_ATTR_RO(write_ns);
4803
4804 /**
4805  * in_flight_show - number of I/Os currently in flight -
4806  * in most cases this will be either 0 or 1. It may be higher if someone
4807  * has also issued other SCSI commands such as via an ioctl.
4808  * @dev: struct device
4809  * @attr: attribute structure
4810  * @buf: buffer to return formatted data in
4811  */
4812 static ssize_t in_flight_show(struct device *dev,
4813         struct device_attribute *attr, char *buf)
4814 {
4815         struct st_modedef *STm = dev_get_drvdata(dev);
4816
4817         return sprintf(buf, "%lld",
4818                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4819 }
4820 static DEVICE_ATTR_RO(in_flight);
4821
4822 /**
4823  * io_ns_show - io wait ns - this is the number of ns spent
4824  * waiting on all I/O to complete. This includes tape movement commands
4825  * such as rewinding, seeking to end of file or tape, it also includes
4826  * read and write. To determine the time spent on tape movement
4827  * subtract the read and write ns from this value.
4828  * @dev: struct device
4829  * @attr: attribute structure
4830  * @buf: buffer to return formatted data in
4831  */
4832 static ssize_t io_ns_show(struct device *dev,
4833         struct device_attribute *attr, char *buf)
4834 {
4835         struct st_modedef *STm = dev_get_drvdata(dev);
4836
4837         return sprintf(buf, "%lld",
4838                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4839 }
4840 static DEVICE_ATTR_RO(io_ns);
4841
4842 /**
4843  * other_cnt_show - other io count - this is the number of
4844  * I/O requests other than read and write requests.
4845  * Typically these are tape movement requests but will include driver
4846  * tape movement. This includes only requests issued by the st driver.
4847  * @dev: struct device
4848  * @attr: attribute structure
4849  * @buf: buffer to return formatted data in
4850  */
4851 static ssize_t other_cnt_show(struct device *dev,
4852         struct device_attribute *attr, char *buf)
4853 {
4854         struct st_modedef *STm = dev_get_drvdata(dev);
4855
4856         return sprintf(buf, "%lld",
4857                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4858 }
4859 static DEVICE_ATTR_RO(other_cnt);
4860
4861 /**
4862  * resid_cnt_show - A count of the number of times we get a residual
4863  * count - this should indicate someone issuing reads larger than the
4864  * block size on tape.
4865  * @dev: struct device
4866  * @attr: attribute structure
4867  * @buf: buffer to return formatted data in
4868  */
4869 static ssize_t resid_cnt_show(struct device *dev,
4870         struct device_attribute *attr, char *buf)
4871 {
4872         struct st_modedef *STm = dev_get_drvdata(dev);
4873
4874         return sprintf(buf, "%lld",
4875                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4876 }
4877 static DEVICE_ATTR_RO(resid_cnt);
4878
4879 static struct attribute *st_dev_attrs[] = {
4880         &dev_attr_defined.attr,
4881         &dev_attr_default_blksize.attr,
4882         &dev_attr_default_density.attr,
4883         &dev_attr_default_compression.attr,
4884         &dev_attr_options.attr,
4885         NULL,
4886 };
4887
4888 static struct attribute *st_stats_attrs[] = {
4889         &dev_attr_read_cnt.attr,
4890         &dev_attr_read_byte_cnt.attr,
4891         &dev_attr_read_ns.attr,
4892         &dev_attr_write_cnt.attr,
4893         &dev_attr_write_byte_cnt.attr,
4894         &dev_attr_write_ns.attr,
4895         &dev_attr_in_flight.attr,
4896         &dev_attr_io_ns.attr,
4897         &dev_attr_other_cnt.attr,
4898         &dev_attr_resid_cnt.attr,
4899         NULL,
4900 };
4901
4902 static struct attribute_group stats_group = {
4903         .name = "stats",
4904         .attrs = st_stats_attrs,
4905 };
4906
4907 static struct attribute_group st_group = {
4908         .attrs = st_dev_attrs,
4909 };
4910
4911 static const struct attribute_group *st_dev_groups[] = {
4912         &st_group,
4913         &stats_group,
4914         NULL,
4915 };
4916
4917 /* The following functions may be useful for a larger audience. */
4918 static int sgl_map_user_pages(struct st_buffer *STbp,
4919                               const unsigned int max_pages, unsigned long uaddr,
4920                               size_t count, int rw)
4921 {
4922         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4923         unsigned long start = uaddr >> PAGE_SHIFT;
4924         const int nr_pages = end - start;
4925         int res, i, j;
4926         struct page **pages;
4927         struct rq_map_data *mdata = &STbp->map_data;
4928
4929         /* User attempted Overflow! */
4930         if ((uaddr + count) < uaddr)
4931                 return -EINVAL;
4932
4933         /* Too big */
4934         if (nr_pages > max_pages)
4935                 return -ENOMEM;
4936
4937         /* Hmm? */
4938         if (count == 0)
4939                 return 0;
4940
4941         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4942         if (pages == NULL)
4943                 return -ENOMEM;
4944
4945         /* Try to fault in all of the necessary pages */
4946         /* rw==READ means read from drive, write into memory area */
4947         res = get_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4948                                   pages);
4949
4950         /* Errors and no page mapped should return here */
4951         if (res < nr_pages)
4952                 goto out_unmap;
4953
4954         for (i=0; i < nr_pages; i++) {
4955                 /* FIXME: flush superflous for rw==READ,
4956                  * probably wrong function for rw==WRITE
4957                  */
4958                 flush_dcache_page(pages[i]);
4959         }
4960
4961         mdata->offset = uaddr & ~PAGE_MASK;
4962         STbp->mapped_pages = pages;
4963
4964         return nr_pages;
4965  out_unmap:
4966         if (res > 0) {
4967                 for (j=0; j < res; j++)
4968                         put_page(pages[j]);
4969                 res = 0;
4970         }
4971         kfree(pages);
4972         return res;
4973 }
4974
4975
4976 /* And unmap them... */
4977 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4978                                 const unsigned int nr_pages, int dirtied)
4979 {
4980         int i;
4981
4982         for (i=0; i < nr_pages; i++) {
4983                 struct page *page = STbp->mapped_pages[i];
4984
4985                 if (dirtied)
4986                         SetPageDirty(page);
4987                 /* FIXME: cache flush missing for rw==READ
4988                  * FIXME: call the correct reference counting function
4989                  */
4990                 put_page(page);
4991         }
4992         kfree(STbp->mapped_pages);
4993         STbp->mapped_pages = NULL;
4994
4995         return 0;
4996 }