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);
 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                         fallthrough;
 343                 case 0x70:
 344                         s->fixed_format = 1;
 345                         s->flags = sense[2] & 0xe0;
 346                         break;
 347                 case 0x73:
 348                         s->deferred = 1;
 349                         fallthrough;
 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 0, host bt 0x%x).\n",
 394                                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_DRV_OUT : REQ_OP_DRV_IN, 0);
 553         if (IS_ERR(req))
 554                 return PTR_ERR(req);
 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 err;
 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(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                 DEBC_printk(STp, "Device already in use.\n");
1273                 scsi_tape_put(STp);
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)) {
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         struct scsi_tape *STp = filp->private_data;
1461
1462         if (STp->door_locked == ST_LOCKED_AUTO)
1463                 do_door_lock(STp, 0);
1464
1465         normalize_buffer(STp->buffer);
1466         spin_lock(&st_use_lock);
1467         STp->in_use = 0;
1468         spin_unlock(&st_use_lock);
1469         scsi_autopm_put_device(STp->device);
1470         scsi_tape_put(STp);
1471
1472         return 0;
1473 }
1474
1475 /* The checks common to both reading and writing */
1476 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1477 {
1478         ssize_t retval = 0;
1479
1480         /*
1481          * If we are in the middle of error recovery, don't let anyone
1482          * else try and use this device.  Also, if error recovery fails, it
1483          * may try and take the device offline, in which case all further
1484          * access to the device is prohibited.
1485          */
1486         if (!scsi_block_when_processing_errors(STp->device)) {
1487                 retval = (-ENXIO);
1488                 goto out;
1489         }
1490
1491         if (STp->ready != ST_READY) {
1492                 if (STp->ready == ST_NO_TAPE)
1493                         retval = (-ENOMEDIUM);
1494                 else
1495                         retval = (-EIO);
1496                 goto out;
1497         }
1498
1499         if (! STp->modes[STp->current_mode].defined) {
1500                 retval = (-ENXIO);
1501                 goto out;
1502         }
1503
1504
1505         /*
1506          * If there was a bus reset, block further access
1507          * to this device.
1508          */
1509         if (STp->pos_unknown) {
1510                 retval = (-EIO);
1511                 goto out;
1512         }
1513
1514         if (count == 0)
1515                 goto out;
1516
1517         DEB(
1518         if (!STp->in_use) {
1519                 st_printk(ST_DEB_MSG, STp,
1520                           "Incorrect device.\n");
1521                 retval = (-EIO);
1522                 goto out;
1523         } ) /* end DEB */
1524
1525         if (STp->can_partitions &&
1526             (retval = switch_partition(STp)) < 0)
1527                 goto out;
1528
1529         if (STp->block_size == 0 && STp->max_block > 0 &&
1530             (count < STp->min_block || count > STp->max_block)) {
1531                 retval = (-EINVAL);
1532                 goto out;
1533         }
1534
1535         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1536             !do_door_lock(STp, 1))
1537                 STp->door_locked = ST_LOCKED_AUTO;
1538
1539  out:
1540         return retval;
1541 }
1542
1543
1544 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1545                            size_t count, int is_read)
1546 {
1547         int i, bufsize, retval = 0;
1548         struct st_buffer *STbp = STp->buffer;
1549
1550         if (is_read)
1551                 i = STp->try_dio_now && try_rdio;
1552         else
1553                 i = STp->try_dio_now && try_wdio;
1554
1555         if (i && ((unsigned long)buf & queue_dma_alignment(
1556                                         STp->device->request_queue)) == 0) {
1557                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1558                                        count, (is_read ? READ : WRITE));
1559                 if (i > 0) {
1560                         STbp->do_dio = i;
1561                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1562                 }
1563                 else
1564                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1565                 STbp->sg_segs = STbp->do_dio;
1566                 DEB(
1567                      if (STbp->do_dio) {
1568                         STp->nbr_dio++;
1569                         STp->nbr_pages += STbp->do_dio;
1570                      }
1571                 )
1572         } else
1573                 STbp->do_dio = 0;
1574         DEB( STp->nbr_requests++; )
1575
1576         if (!STbp->do_dio) {
1577                 if (STp->block_size)
1578                         bufsize = STp->block_size > st_fixed_buffer_size ?
1579                                 STp->block_size : st_fixed_buffer_size;
1580                 else {
1581                         bufsize = count;
1582                         /* Make sure that data from previous user is not leaked even if
1583                            HBA does not return correct residual */
1584                         if (is_read && STp->sili && !STbp->cleared)
1585                                 clear_buffer(STbp);
1586                 }
1587
1588                 if (bufsize > STbp->buffer_size &&
1589                     !enlarge_buffer(STbp, bufsize)) {
1590                         st_printk(KERN_WARNING, STp,
1591                                   "Can't allocate %d byte tape buffer.\n",
1592                                   bufsize);
1593                         retval = (-EOVERFLOW);
1594                         goto out;
1595                 }
1596                 if (STp->block_size)
1597                         STbp->buffer_blocks = bufsize / STp->block_size;
1598         }
1599
1600  out:
1601         return retval;
1602 }
1603
1604
1605 /* Can be called more than once after each setup_buffer() */
1606 static void release_buffering(struct scsi_tape *STp, int is_read)
1607 {
1608         struct st_buffer *STbp;
1609
1610         STbp = STp->buffer;
1611         if (STbp->do_dio) {
1612                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1613                 STbp->do_dio = 0;
1614                 STbp->sg_segs = 0;
1615         }
1616 }
1617
1618
1619 /* Write command */
1620 static ssize_t
1621 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1622 {
1623         ssize_t total;
1624         ssize_t i, do_count, blks, transfer;
1625         ssize_t retval;
1626         int undone, retry_eot = 0, scode;
1627         int async_write;
1628         unsigned char cmd[MAX_COMMAND_SIZE];
1629         const char __user *b_point;
1630         struct st_request *SRpnt = NULL;
1631         struct scsi_tape *STp = filp->private_data;
1632         struct st_modedef *STm;
1633         struct st_partstat *STps;
1634         struct st_buffer *STbp;
1635
1636         if (mutex_lock_interruptible(&STp->lock))
1637                 return -ERESTARTSYS;
1638
1639         retval = rw_checks(STp, filp, count);
1640         if (retval || count == 0)
1641                 goto out;
1642
1643         /* Write must be integral number of blocks */
1644         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1645                 st_printk(KERN_WARNING, STp,
1646                           "Write not multiple of tape block size.\n");
1647                 retval = (-EINVAL);
1648                 goto out;
1649         }
1650
1651         STm = &(STp->modes[STp->current_mode]);
1652         STps = &(STp->ps[STp->partition]);
1653
1654         if (STp->write_prot) {
1655                 retval = (-EACCES);
1656                 goto out;
1657         }
1658
1659
1660         if (STps->rw == ST_READING) {
1661                 retval = flush_buffer(STp, 0);
1662                 if (retval)
1663                         goto out;
1664                 STps->rw = ST_WRITING;
1665         } else if (STps->rw != ST_WRITING &&
1666                    STps->drv_file == 0 && STps->drv_block == 0) {
1667                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1668                         goto out;
1669                 if (STm->default_compression != ST_DONT_TOUCH &&
1670                     !(STp->compression_changed)) {
1671                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1672                                 st_printk(KERN_WARNING, STp,
1673                                           "Can't set default compression.\n");
1674                                 if (modes_defined) {
1675                                         retval = (-EINVAL);
1676                                         goto out;
1677                                 }
1678                         }
1679                 }
1680         }
1681
1682         STbp = STp->buffer;
1683         i = write_behind_check(STp);
1684         if (i) {
1685                 if (i == -ENOSPC)
1686                         STps->eof = ST_EOM_OK;
1687                 else
1688                         STps->eof = ST_EOM_ERROR;
1689         }
1690
1691         if (STps->eof == ST_EOM_OK) {
1692                 STps->eof = ST_EOD_1;  /* allow next write */
1693                 retval = (-ENOSPC);
1694                 goto out;
1695         }
1696         else if (STps->eof == ST_EOM_ERROR) {
1697                 retval = (-EIO);
1698                 goto out;
1699         }
1700
1701         /* Check the buffer readability in cases where copy_user might catch
1702            the problems after some tape movement. */
1703         if (STp->block_size != 0 &&
1704             !STbp->do_dio &&
1705             (copy_from_user(&i, buf, 1) != 0 ||
1706              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1707                 retval = (-EFAULT);
1708                 goto out;
1709         }
1710
1711         retval = setup_buffering(STp, buf, count, 0);
1712         if (retval)
1713                 goto out;
1714
1715         total = count;
1716
1717         memset(cmd, 0, MAX_COMMAND_SIZE);
1718         cmd[0] = WRITE_6;
1719         cmd[1] = (STp->block_size != 0);
1720
1721         STps->rw = ST_WRITING;
1722
1723         b_point = buf;
1724         while (count > 0 && !retry_eot) {
1725
1726                 if (STbp->do_dio) {
1727                         do_count = count;
1728                 }
1729                 else {
1730                         if (STp->block_size == 0)
1731                                 do_count = count;
1732                         else {
1733                                 do_count = STbp->buffer_blocks * STp->block_size -
1734                                         STbp->buffer_bytes;
1735                                 if (do_count > count)
1736                                         do_count = count;
1737                         }
1738
1739                         i = append_to_buffer(b_point, STbp, do_count);
1740                         if (i) {
1741                                 retval = i;
1742                                 goto out;
1743                         }
1744                 }
1745                 count -= do_count;
1746                 b_point += do_count;
1747
1748                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1749                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1750
1751                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1752                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1753                     STbp->buffer_bytes < STbp->buffer_size) {
1754                         STp->dirty = 1;
1755                         /* Don't write a buffer that is not full enough. */
1756                         if (!async_write && count == 0)
1757                                 break;
1758                 }
1759
1760         retry_write:
1761                 if (STp->block_size == 0)
1762                         blks = transfer = do_count;
1763                 else {
1764                         if (!STbp->do_dio)
1765                                 blks = STbp->buffer_bytes;
1766                         else
1767                                 blks = do_count;
1768                         blks /= STp->block_size;
1769                         transfer = blks * STp->block_size;
1770                 }
1771                 cmd[2] = blks >> 16;
1772                 cmd[3] = blks >> 8;
1773                 cmd[4] = blks;
1774
1775                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1776                                    STp->device->request_queue->rq_timeout,
1777                                    MAX_WRITE_RETRIES, !async_write);
1778                 if (!SRpnt) {
1779                         retval = STbp->syscall_result;
1780                         goto out;
1781                 }
1782                 if (async_write && !STbp->syscall_result) {
1783                         STbp->writing = transfer;
1784                         STp->dirty = !(STbp->writing ==
1785                                        STbp->buffer_bytes);
1786                         SRpnt = NULL;  /* Prevent releasing this request! */
1787                         DEB( STp->write_pending = 1; )
1788                         break;
1789                 }
1790
1791                 if (STbp->syscall_result != 0) {
1792                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1793
1794                         DEBC_printk(STp, "Error on write:\n");
1795                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1796                                 scode = cmdstatp->sense_hdr.sense_key;
1797                                 if (cmdstatp->remainder_valid)
1798                                         undone = (int)cmdstatp->uremainder64;
1799                                 else if (STp->block_size == 0 &&
1800                                          scode == VOLUME_OVERFLOW)
1801                                         undone = transfer;
1802                                 else
1803                                         undone = 0;
1804                                 if (STp->block_size != 0)
1805                                         undone *= STp->block_size;
1806                                 if (undone <= do_count) {
1807                                         /* Only data from this write is not written */
1808                                         count += undone;
1809                                         b_point -= undone;
1810                                         do_count -= undone;
1811                                         if (STp->block_size)
1812                                                 blks = (transfer - undone) / STp->block_size;
1813                                         STps->eof = ST_EOM_OK;
1814                                         /* Continue in fixed block mode if all written
1815                                            in this request but still something left to write
1816                                            (retval left to zero)
1817                                         */
1818                                         if (STp->block_size == 0 ||
1819                                             undone > 0 || count == 0)
1820                                                 retval = (-ENOSPC); /* EOM within current request */
1821                                         DEBC_printk(STp, "EOM with %d "
1822                                                     "bytes unwritten.\n",
1823                                                     (int)count);
1824                                 } else {
1825                                         /* EOT within data buffered earlier (possible only
1826                                            in fixed block mode without direct i/o) */
1827                                         if (!retry_eot && !cmdstatp->deferred &&
1828                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1829                                                 move_buffer_data(STp->buffer, transfer - undone);
1830                                                 retry_eot = 1;
1831                                                 if (STps->drv_block >= 0) {
1832                                                         STps->drv_block += (transfer - undone) /
1833                                                                 STp->block_size;
1834                                                 }
1835                                                 STps->eof = ST_EOM_OK;
1836                                                 DEBC_printk(STp, "Retry "
1837                                                             "write of %d "
1838                                                             "bytes at EOM.\n",
1839                                                             STp->buffer->buffer_bytes);
1840                                                 goto retry_write;
1841                                         }
1842                                         else {
1843                                                 /* Either error within data buffered by driver or
1844                                                    failed retry */
1845                                                 count -= do_count;
1846                                                 blks = do_count = 0;
1847                                                 STps->eof = ST_EOM_ERROR;
1848                                                 STps->drv_block = (-1); /* Too cautious? */
1849                                                 retval = (-EIO);        /* EOM for old data */
1850                                                 DEBC_printk(STp, "EOM with "
1851                                                             "lost data.\n");
1852                                         }
1853                                 }
1854                         } else {
1855                                 count += do_count;
1856                                 STps->drv_block = (-1);         /* Too cautious? */
1857                                 retval = STbp->syscall_result;
1858                         }
1859
1860                 }
1861
1862                 if (STps->drv_block >= 0) {
1863                         if (STp->block_size == 0)
1864                                 STps->drv_block += (do_count > 0);
1865                         else
1866                                 STps->drv_block += blks;
1867                 }
1868
1869                 STbp->buffer_bytes = 0;
1870                 STp->dirty = 0;
1871
1872                 if (retval || retry_eot) {
1873                         if (count < total)
1874                                 retval = total - count;
1875                         goto out;
1876                 }
1877         }
1878
1879         if (STps->eof == ST_EOD_1)
1880                 STps->eof = ST_EOM_OK;
1881         else if (STps->eof != ST_EOM_OK)
1882                 STps->eof = ST_NOEOF;
1883         retval = total - count;
1884
1885  out:
1886         if (SRpnt != NULL)
1887                 st_release_request(SRpnt);
1888         release_buffering(STp, 0);
1889         mutex_unlock(&STp->lock);
1890
1891         return retval;
1892 }
1893 \f
1894 /* Read data from the tape. Returns zero in the normal case, one if the
1895    eof status has changed, and the negative error code in case of a
1896    fatal error. Otherwise updates the buffer and the eof state.
1897
1898    Does release user buffer mapping if it is set.
1899 */
1900 static long read_tape(struct scsi_tape *STp, long count,
1901                       struct st_request ** aSRpnt)
1902 {
1903         int transfer, blks, bytes;
1904         unsigned char cmd[MAX_COMMAND_SIZE];
1905         struct st_request *SRpnt;
1906         struct st_modedef *STm;
1907         struct st_partstat *STps;
1908         struct st_buffer *STbp;
1909         int retval = 0;
1910
1911         if (count == 0)
1912                 return 0;
1913
1914         STm = &(STp->modes[STp->current_mode]);
1915         STps = &(STp->ps[STp->partition]);
1916         if (STps->eof == ST_FM_HIT)
1917                 return 1;
1918         STbp = STp->buffer;
1919
1920         if (STp->block_size == 0)
1921                 blks = bytes = count;
1922         else {
1923                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1924                         blks = (STp->buffer)->buffer_blocks;
1925                         bytes = blks * STp->block_size;
1926                 } else {
1927                         bytes = count;
1928                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1929                                 bytes = (STp->buffer)->buffer_size;
1930                         blks = bytes / STp->block_size;
1931                         bytes = blks * STp->block_size;
1932                 }
1933         }
1934
1935         memset(cmd, 0, MAX_COMMAND_SIZE);
1936         cmd[0] = READ_6;
1937         cmd[1] = (STp->block_size != 0);
1938         if (!cmd[1] && STp->sili)
1939                 cmd[1] |= 2;
1940         cmd[2] = blks >> 16;
1941         cmd[3] = blks >> 8;
1942         cmd[4] = blks;
1943
1944         SRpnt = *aSRpnt;
1945         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1946                            STp->device->request_queue->rq_timeout,
1947                            MAX_RETRIES, 1);
1948         release_buffering(STp, 1);
1949         *aSRpnt = SRpnt;
1950         if (!SRpnt)
1951                 return STbp->syscall_result;
1952
1953         STbp->read_pointer = 0;
1954         STps->at_sm = 0;
1955
1956         /* Something to check */
1957         if (STbp->syscall_result) {
1958                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1959
1960                 retval = 1;
1961                 DEBC_printk(STp,
1962                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1963                             SRpnt->sense[0], SRpnt->sense[1],
1964                             SRpnt->sense[2], SRpnt->sense[3],
1965                             SRpnt->sense[4], SRpnt->sense[5],
1966                             SRpnt->sense[6], SRpnt->sense[7]);
1967                 if (cmdstatp->have_sense) {
1968
1969                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1970                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1971
1972                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1973                                 /* Compute the residual count */
1974                                 if (cmdstatp->remainder_valid)
1975                                         transfer = (int)cmdstatp->uremainder64;
1976                                 else
1977                                         transfer = 0;
1978                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1979                                         if (STp->block_size == 0)
1980                                                 transfer = bytes;
1981                                         /* Some drives set ILI with MEDIUM ERROR */
1982                                         cmdstatp->flags &= ~SENSE_ILI;
1983                                 }
1984
1985                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1986                                         if (STp->block_size == 0 &&
1987                                             transfer < 0) {
1988                                                 st_printk(KERN_NOTICE, STp,
1989                                                           "Failed to read %d "
1990                                                           "byte block with %d "
1991                                                           "byte transfer.\n",
1992                                                           bytes - transfer,
1993                                                           bytes);
1994                                                 if (STps->drv_block >= 0)
1995                                                         STps->drv_block += 1;
1996                                                 STbp->buffer_bytes = 0;
1997                                                 return (-ENOMEM);
1998                                         } else if (STp->block_size == 0) {
1999                                                 STbp->buffer_bytes = bytes - transfer;
2000                                         } else {
2001                                                 st_release_request(SRpnt);
2002                                                 SRpnt = *aSRpnt = NULL;
2003                                                 if (transfer == blks) { /* We did not get anything, error */
2004                                                         st_printk(KERN_NOTICE, STp,
2005                                                                   "Incorrect "
2006                                                                   "block size.\n");
2007                                                         if (STps->drv_block >= 0)
2008                                                                 STps->drv_block += blks - transfer + 1;
2009                                                         st_int_ioctl(STp, MTBSR, 1);
2010                                                         return (-EIO);
2011                                                 }
2012                                                 /* We have some data, deliver it */
2013                                                 STbp->buffer_bytes = (blks - transfer) *
2014                                                     STp->block_size;
2015                                                 DEBC_printk(STp, "ILI but "
2016                                                             "enough data "
2017                                                             "received %ld "
2018                                                             "%d.\n", count,
2019                                                             STbp->buffer_bytes);
2020                                                 if (STps->drv_block >= 0)
2021                                                         STps->drv_block += 1;
2022                                                 if (st_int_ioctl(STp, MTBSR, 1))
2023                                                         return (-EIO);
2024                                         }
2025                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2026                                         if (STps->eof != ST_FM_HIT)
2027                                                 STps->eof = ST_FM_HIT;
2028                                         else
2029                                                 STps->eof = ST_EOD_2;
2030                                         if (STp->block_size == 0)
2031                                                 STbp->buffer_bytes = 0;
2032                                         else
2033                                                 STbp->buffer_bytes =
2034                                                     bytes - transfer * STp->block_size;
2035                                         DEBC_printk(STp, "EOF detected (%d "
2036                                                     "bytes read).\n",
2037                                                     STbp->buffer_bytes);
2038                                 } else if (cmdstatp->flags & SENSE_EOM) {
2039                                         if (STps->eof == ST_FM)
2040                                                 STps->eof = ST_EOD_1;
2041                                         else
2042                                                 STps->eof = ST_EOM_OK;
2043                                         if (STp->block_size == 0)
2044                                                 STbp->buffer_bytes = bytes - transfer;
2045                                         else
2046                                                 STbp->buffer_bytes =
2047                                                     bytes - transfer * STp->block_size;
2048
2049                                         DEBC_printk(STp, "EOM detected (%d "
2050                                                     "bytes read).\n",
2051                                                     STbp->buffer_bytes);
2052                                 }
2053                         }
2054                         /* end of EOF, EOM, ILI test */
2055                         else {  /* nonzero sense key */
2056                                 DEBC_printk(STp, "Tape error while reading.\n");
2057                                 STps->drv_block = (-1);
2058                                 if (STps->eof == ST_FM &&
2059                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2060                                         DEBC_printk(STp, "Zero returned for "
2061                                                     "first BLANK CHECK "
2062                                                     "after EOF.\n");
2063                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2064                                 } else  /* Some other extended sense code */
2065                                         retval = (-EIO);
2066                         }
2067
2068                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2069                                 STbp->buffer_bytes = 0;
2070                 }
2071                 /* End of extended sense test */
2072                 else {          /* Non-extended sense */
2073                         retval = STbp->syscall_result;
2074                 }
2075
2076         }
2077         /* End of error handling */
2078         else {                  /* Read successful */
2079                 STbp->buffer_bytes = bytes;
2080                 if (STp->sili) /* In fixed block mode residual is always zero here */
2081                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2082         }
2083
2084         if (STps->drv_block >= 0) {
2085                 if (STp->block_size == 0)
2086                         STps->drv_block++;
2087                 else
2088                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2089         }
2090         return retval;
2091 }
2092 \f
2093
2094 /* Read command */
2095 static ssize_t
2096 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2097 {
2098         ssize_t total;
2099         ssize_t retval = 0;
2100         ssize_t i, transfer;
2101         int special, do_dio = 0;
2102         struct st_request *SRpnt = NULL;
2103         struct scsi_tape *STp = filp->private_data;
2104         struct st_modedef *STm;
2105         struct st_partstat *STps;
2106         struct st_buffer *STbp = STp->buffer;
2107
2108         if (mutex_lock_interruptible(&STp->lock))
2109                 return -ERESTARTSYS;
2110
2111         retval = rw_checks(STp, filp, count);
2112         if (retval || count == 0)
2113                 goto out;
2114
2115         STm = &(STp->modes[STp->current_mode]);
2116         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2117                 if (!STm->do_read_ahead) {
2118                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2119                         goto out;
2120                 }
2121                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2122         }
2123
2124         STps = &(STp->ps[STp->partition]);
2125         if (STps->rw == ST_WRITING) {
2126                 retval = flush_buffer(STp, 0);
2127                 if (retval)
2128                         goto out;
2129                 STps->rw = ST_READING;
2130         }
2131         DEB(
2132         if (debugging && STps->eof != ST_NOEOF)
2133                 st_printk(ST_DEB_MSG, STp,
2134                           "EOF/EOM flag up (%d). Bytes %d\n",
2135                           STps->eof, STbp->buffer_bytes);
2136         ) /* end DEB */
2137
2138         retval = setup_buffering(STp, buf, count, 1);
2139         if (retval)
2140                 goto out;
2141         do_dio = STbp->do_dio;
2142
2143         if (STbp->buffer_bytes == 0 &&
2144             STps->eof >= ST_EOD_1) {
2145                 if (STps->eof < ST_EOD) {
2146                         STps->eof += 1;
2147                         retval = 0;
2148                         goto out;
2149                 }
2150                 retval = (-EIO);        /* EOM or Blank Check */
2151                 goto out;
2152         }
2153
2154         if (do_dio) {
2155                 /* Check the buffer writability before any tape movement. Don't alter
2156                    buffer data. */
2157                 if (copy_from_user(&i, buf, 1) != 0 ||
2158                     copy_to_user(buf, &i, 1) != 0 ||
2159                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2160                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2161                         retval = (-EFAULT);
2162                         goto out;
2163                 }
2164         }
2165
2166         STps->rw = ST_READING;
2167
2168
2169         /* Loop until enough data in buffer or a special condition found */
2170         for (total = 0, special = 0; total < count && !special;) {
2171
2172                 /* Get new data if the buffer is empty */
2173                 if (STbp->buffer_bytes == 0) {
2174                         special = read_tape(STp, count - total, &SRpnt);
2175                         if (special < 0) {      /* No need to continue read */
2176                                 retval = special;
2177                                 goto out;
2178                         }
2179                 }
2180
2181                 /* Move the data from driver buffer to user buffer */
2182                 if (STbp->buffer_bytes > 0) {
2183                         DEB(
2184                         if (debugging && STps->eof != ST_NOEOF)
2185                                 st_printk(ST_DEB_MSG, STp,
2186                                           "EOF up (%d). Left %d, needed %d.\n",
2187                                           STps->eof, STbp->buffer_bytes,
2188                                           (int)(count - total));
2189                         ) /* end DEB */
2190                         transfer = STbp->buffer_bytes < count - total ?
2191                             STbp->buffer_bytes : count - total;
2192                         if (!do_dio) {
2193                                 i = from_buffer(STbp, buf, transfer);
2194                                 if (i) {
2195                                         retval = i;
2196                                         goto out;
2197                                 }
2198                         }
2199                         buf += transfer;
2200                         total += transfer;
2201                 }
2202
2203                 if (STp->block_size == 0)
2204                         break;  /* Read only one variable length block */
2205
2206         }                       /* for (total = 0, special = 0;
2207                                    total < count && !special; ) */
2208
2209         /* Change the eof state if no data from tape or buffer */
2210         if (total == 0) {
2211                 if (STps->eof == ST_FM_HIT) {
2212                         STps->eof = ST_FM;
2213                         STps->drv_block = 0;
2214                         if (STps->drv_file >= 0)
2215                                 STps->drv_file++;
2216                 } else if (STps->eof == ST_EOD_1) {
2217                         STps->eof = ST_EOD_2;
2218                         STps->drv_block = 0;
2219                         if (STps->drv_file >= 0)
2220                                 STps->drv_file++;
2221                 } else if (STps->eof == ST_EOD_2)
2222                         STps->eof = ST_EOD;
2223         } else if (STps->eof == ST_FM)
2224                 STps->eof = ST_NOEOF;
2225         retval = total;
2226
2227  out:
2228         if (SRpnt != NULL) {
2229                 st_release_request(SRpnt);
2230                 SRpnt = NULL;
2231         }
2232         if (do_dio) {
2233                 release_buffering(STp, 1);
2234                 STbp->buffer_bytes = 0;
2235         }
2236         mutex_unlock(&STp->lock);
2237
2238         return retval;
2239 }
2240 \f
2241
2242
2243 DEB(
2244 /* Set the driver options */
2245 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2246 {
2247         if (debugging) {
2248                 st_printk(KERN_INFO, STp,
2249                           "Mode %d options: buffer writes: %d, "
2250                           "async writes: %d, read ahead: %d\n",
2251                           STp->current_mode, STm->do_buffer_writes,
2252                           STm->do_async_writes, STm->do_read_ahead);
2253                 st_printk(KERN_INFO, STp,
2254                           "    can bsr: %d, two FMs: %d, "
2255                           "fast mteom: %d, auto lock: %d,\n",
2256                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2257                           STp->do_auto_lock);
2258                 st_printk(KERN_INFO, STp,
2259                           "    defs for wr: %d, no block limits: %d, "
2260                           "partitions: %d, s2 log: %d\n",
2261                           STm->defaults_for_writes, STp->omit_blklims,
2262                           STp->can_partitions, STp->scsi2_logical);
2263                 st_printk(KERN_INFO, STp,
2264                           "    sysv: %d nowait: %d sili: %d "
2265                           "nowait_filemark: %d\n",
2266                           STm->sysv, STp->immediate, STp->sili,
2267                           STp->immediate_filemark);
2268                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2269         }
2270 }
2271         )
2272
2273
2274 static int st_set_options(struct scsi_tape *STp, long options)
2275 {
2276         int value;
2277         long code;
2278         struct st_modedef *STm;
2279         struct cdev *cd0, *cd1;
2280         struct device *d0, *d1;
2281
2282         STm = &(STp->modes[STp->current_mode]);
2283         if (!STm->defined) {
2284                 cd0 = STm->cdevs[0];
2285                 cd1 = STm->cdevs[1];
2286                 d0  = STm->devs[0];
2287                 d1  = STm->devs[1];
2288                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2289                 STm->cdevs[0] = cd0;
2290                 STm->cdevs[1] = cd1;
2291                 STm->devs[0]  = d0;
2292                 STm->devs[1]  = d1;
2293                 modes_defined = 1;
2294                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2295                             STp->current_mode);
2296         }
2297
2298         code = options & MT_ST_OPTIONS;
2299         if (code == MT_ST_BOOLEANS) {
2300                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2301                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2302                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2303                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2304                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2305                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2306                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2307                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2308                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2309                 if ((STp->device)->scsi_level >= SCSI_2)
2310                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2311                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2312                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2313                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2314                 STm->sysv = (options & MT_ST_SYSV) != 0;
2315                 STp->sili = (options & MT_ST_SILI) != 0;
2316                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2317                      st_log_options(STp, STm); )
2318         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2319                 value = (code == MT_ST_SETBOOLEANS);
2320                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2321                         STm->do_buffer_writes = value;
2322                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2323                         STm->do_async_writes = value;
2324                 if ((options & MT_ST_DEF_WRITES) != 0)
2325                         STm->defaults_for_writes = value;
2326                 if ((options & MT_ST_READ_AHEAD) != 0)
2327                         STm->do_read_ahead = value;
2328                 if ((options & MT_ST_TWO_FM) != 0)
2329                         STp->two_fm = value;
2330                 if ((options & MT_ST_FAST_MTEOM) != 0)
2331                         STp->fast_mteom = value;
2332                 if ((options & MT_ST_AUTO_LOCK) != 0)
2333                         STp->do_auto_lock = value;
2334                 if ((options & MT_ST_CAN_BSR) != 0)
2335                         STp->can_bsr = value;
2336                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2337                         STp->omit_blklims = value;
2338                 if ((STp->device)->scsi_level >= SCSI_2 &&
2339                     (options & MT_ST_CAN_PARTITIONS) != 0)
2340                         STp->can_partitions = value;
2341                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2342                         STp->scsi2_logical = value;
2343                 if ((options & MT_ST_NOWAIT) != 0)
2344                         STp->immediate = value;
2345                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2346                         STp->immediate_filemark = value;
2347                 if ((options & MT_ST_SYSV) != 0)
2348                         STm->sysv = value;
2349                 if ((options & MT_ST_SILI) != 0)
2350                         STp->sili = value;
2351                 DEB(
2352                 if ((options & MT_ST_DEBUGGING) != 0)
2353                         debugging = value;
2354                         st_log_options(STp, STm); )
2355         } else if (code == MT_ST_WRITE_THRESHOLD) {
2356                 /* Retained for compatibility */
2357         } else if (code == MT_ST_DEF_BLKSIZE) {
2358                 value = (options & ~MT_ST_OPTIONS);
2359                 if (value == ~MT_ST_OPTIONS) {
2360                         STm->default_blksize = (-1);
2361                         DEBC_printk(STp, "Default block size disabled.\n");
2362                 } else {
2363                         STm->default_blksize = value;
2364                         DEBC_printk(STp,"Default block size set to "
2365                                     "%d bytes.\n", STm->default_blksize);
2366                         if (STp->ready == ST_READY) {
2367                                 STp->blksize_changed = 0;
2368                                 set_mode_densblk(STp, STm);
2369                         }
2370                 }
2371         } else if (code == MT_ST_TIMEOUTS) {
2372                 value = (options & ~MT_ST_OPTIONS);
2373                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2374                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2375                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2376                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2377                 } else {
2378                         blk_queue_rq_timeout(STp->device->request_queue,
2379                                              value * HZ);
2380                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2381                                     value);
2382                 }
2383         } else if (code == MT_ST_SET_CLN) {
2384                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2385                 if (value != 0 &&
2386                         (value < EXTENDED_SENSE_START ||
2387                                 value >= SCSI_SENSE_BUFFERSIZE))
2388                         return (-EINVAL);
2389                 STp->cln_mode = value;
2390                 STp->cln_sense_mask = (options >> 8) & 0xff;
2391                 STp->cln_sense_value = (options >> 16) & 0xff;
2392                 st_printk(KERN_INFO, STp,
2393                           "Cleaning request mode %d, mask %02x, value %02x\n",
2394                           value, STp->cln_sense_mask, STp->cln_sense_value);
2395         } else if (code == MT_ST_DEF_OPTIONS) {
2396                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2397                 value = (options & MT_ST_CLEAR_DEFAULT);
2398                 if (code == MT_ST_DEF_DENSITY) {
2399                         if (value == MT_ST_CLEAR_DEFAULT) {
2400                                 STm->default_density = (-1);
2401                                 DEBC_printk(STp,
2402                                             "Density default disabled.\n");
2403                         } else {
2404                                 STm->default_density = value & 0xff;
2405                                 DEBC_printk(STp, "Density default set to %x\n",
2406                                             STm->default_density);
2407                                 if (STp->ready == ST_READY) {
2408                                         STp->density_changed = 0;
2409                                         set_mode_densblk(STp, STm);
2410                                 }
2411                         }
2412                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2413                         if (value == MT_ST_CLEAR_DEFAULT) {
2414                                 STp->default_drvbuffer = 0xff;
2415                                 DEBC_printk(STp,
2416                                             "Drive buffer default disabled.\n");
2417                         } else {
2418                                 STp->default_drvbuffer = value & 7;
2419                                 DEBC_printk(STp,
2420                                             "Drive buffer default set to %x\n",
2421                                             STp->default_drvbuffer);
2422                                 if (STp->ready == ST_READY)
2423                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2424                         }
2425                 } else if (code == MT_ST_DEF_COMPRESSION) {
2426                         if (value == MT_ST_CLEAR_DEFAULT) {
2427                                 STm->default_compression = ST_DONT_TOUCH;
2428                                 DEBC_printk(STp,
2429                                             "Compression default disabled.\n");
2430                         } else {
2431                                 if ((value & 0xff00) != 0) {
2432                                         STp->c_algo = (value & 0xff00) >> 8;
2433                                         DEBC_printk(STp, "Compression "
2434                                                     "algorithm set to 0x%x.\n",
2435                                                     STp->c_algo);
2436                                 }
2437                                 if ((value & 0xff) != 0xff) {
2438                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2439                                         DEBC_printk(STp, "Compression default "
2440                                                     "set to %x\n",
2441                                                     (value & 1));
2442                                         if (STp->ready == ST_READY) {
2443                                                 STp->compression_changed = 0;
2444                                                 st_compression(STp, (STm->default_compression == ST_YES));
2445                                         }
2446                                 }
2447                         }
2448                 }
2449         } else
2450                 return (-EIO);
2451
2452         return 0;
2453 }
2454 \f
2455 #define MODE_HEADER_LENGTH  4
2456
2457 /* Mode header and page byte offsets */
2458 #define MH_OFF_DATA_LENGTH     0
2459 #define MH_OFF_MEDIUM_TYPE     1
2460 #define MH_OFF_DEV_SPECIFIC    2
2461 #define MH_OFF_BDESCS_LENGTH   3
2462 #define MP_OFF_PAGE_NBR        0
2463 #define MP_OFF_PAGE_LENGTH     1
2464
2465 /* Mode header and page bit masks */
2466 #define MH_BIT_WP              0x80
2467 #define MP_MSK_PAGE_NBR        0x3f
2468
2469 /* Don't return block descriptors */
2470 #define MODE_SENSE_OMIT_BDESCS 0x08
2471
2472 #define MODE_SELECT_PAGE_FORMAT 0x10
2473
2474 /* Read a mode page into the tape buffer. The block descriptors are included
2475    if incl_block_descs is true. The page control is ored to the page number
2476    parameter, if necessary. */
2477 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2478 {
2479         unsigned char cmd[MAX_COMMAND_SIZE];
2480         struct st_request *SRpnt;
2481
2482         memset(cmd, 0, MAX_COMMAND_SIZE);
2483         cmd[0] = MODE_SENSE;
2484         if (omit_block_descs)
2485                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2486         cmd[2] = page;
2487         cmd[4] = 255;
2488
2489         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2490                            STp->device->request_queue->rq_timeout, 0, 1);
2491         if (SRpnt == NULL)
2492                 return (STp->buffer)->syscall_result;
2493
2494         st_release_request(SRpnt);
2495
2496         return STp->buffer->syscall_result;
2497 }
2498
2499
2500 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2501    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2502 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2503 {
2504         int pgo;
2505         unsigned char cmd[MAX_COMMAND_SIZE];
2506         struct st_request *SRpnt;
2507         int timeout;
2508
2509         memset(cmd, 0, MAX_COMMAND_SIZE);
2510         cmd[0] = MODE_SELECT;
2511         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2512         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2513         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2514
2515         /* Clear reserved fields */
2516         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2517         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2518         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2519         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2520
2521         timeout = slow ?
2522                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2523         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2524                            timeout, 0, 1);
2525         if (SRpnt == NULL)
2526                 return (STp->buffer)->syscall_result;
2527
2528         st_release_request(SRpnt);
2529
2530         return STp->buffer->syscall_result;
2531 }
2532
2533
2534 #define COMPRESSION_PAGE        0x0f
2535 #define COMPRESSION_PAGE_LENGTH 16
2536
2537 #define CP_OFF_DCE_DCC          2
2538 #define CP_OFF_C_ALGO           7
2539
2540 #define DCE_MASK  0x80
2541 #define DCC_MASK  0x40
2542 #define RED_MASK  0x60
2543
2544
2545 /* Control the compression with mode page 15. Algorithm not changed if zero.
2546
2547    The block descriptors are read and written because Sony SDT-7000 does not
2548    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2549    Including block descriptors should not cause any harm to other drives. */
2550
2551 static int st_compression(struct scsi_tape * STp, int state)
2552 {
2553         int retval;
2554         int mpoffs;  /* Offset to mode page start */
2555         unsigned char *b_data = (STp->buffer)->b_data;
2556
2557         if (STp->ready != ST_READY)
2558                 return (-EIO);
2559
2560         /* Read the current page contents */
2561         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2562         if (retval) {
2563                 DEBC_printk(STp, "Compression mode page not supported.\n");
2564                 return (-EIO);
2565         }
2566
2567         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2568         DEBC_printk(STp, "Compression state is %d.\n",
2569                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2570
2571         /* Check if compression can be changed */
2572         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2573                 DEBC_printk(STp, "Compression not supported.\n");
2574                 return (-EIO);
2575         }
2576
2577         /* Do the change */
2578         if (state) {
2579                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2580                 if (STp->c_algo != 0)
2581                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2582         }
2583         else {
2584                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2585                 if (STp->c_algo != 0)
2586                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2587         }
2588
2589         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2590         if (retval) {
2591                 DEBC_printk(STp, "Compression change failed.\n");
2592                 return (-EIO);
2593         }
2594         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2595
2596         STp->compression_changed = 1;
2597         return 0;
2598 }
2599
2600
2601 /* Process the load and unload commands (does unload if the load code is zero) */
2602 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2603 {
2604         int retval = (-EIO), timeout;
2605         unsigned char cmd[MAX_COMMAND_SIZE];
2606         struct st_partstat *STps;
2607         struct st_request *SRpnt;
2608
2609         if (STp->ready != ST_READY && !load_code) {
2610                 if (STp->ready == ST_NO_TAPE)
2611                         return (-ENOMEDIUM);
2612                 else
2613                         return (-EIO);
2614         }
2615
2616         memset(cmd, 0, MAX_COMMAND_SIZE);
2617         cmd[0] = START_STOP;
2618         if (load_code)
2619                 cmd[4] |= 1;
2620         /*
2621          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2622          */
2623         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2624             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2625                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2626                             (cmd[4]) ? "" : "un",
2627                             load_code - MT_ST_HPLOADER_OFFSET);
2628                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2629         }
2630         if (STp->immediate) {
2631                 cmd[1] = 1;     /* Don't wait for completion */
2632                 timeout = STp->device->request_queue->rq_timeout;
2633         }
2634         else
2635                 timeout = STp->long_timeout;
2636
2637         DEBC(
2638                 if (!load_code)
2639                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2640                 else
2641                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2642                 );
2643
2644         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2645                            timeout, MAX_RETRIES, 1);
2646         if (!SRpnt)
2647                 return (STp->buffer)->syscall_result;
2648
2649         retval = (STp->buffer)->syscall_result;
2650         st_release_request(SRpnt);
2651
2652         if (!retval) {  /* SCSI command successful */
2653
2654                 if (!load_code) {
2655                         STp->rew_at_close = 0;
2656                         STp->ready = ST_NO_TAPE;
2657                 }
2658                 else {
2659                         STp->rew_at_close = STp->autorew_dev;
2660                         retval = check_tape(STp, filp);
2661                         if (retval > 0)
2662                                 retval = 0;
2663                 }
2664         }
2665         else {
2666                 STps = &(STp->ps[STp->partition]);
2667                 STps->drv_file = STps->drv_block = (-1);
2668         }
2669
2670         return retval;
2671 }
2672 \f
2673 #if DEBUG
2674 #define ST_DEB_FORWARD  0
2675 #define ST_DEB_BACKWARD 1
2676 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2677 {
2678         s32 sc;
2679
2680         if (!debugging)
2681                 return;
2682
2683         sc = sign_extend32(get_unaligned_be24(&cmd[2]), 23);
2684         if (direction)
2685                 sc = -sc;
2686         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2687                   direction ? "backward" : "forward", sc, units);
2688 }
2689 #else
2690 #define ST_DEB_FORWARD  0
2691 #define ST_DEB_BACKWARD 1
2692 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2693 #endif
2694
2695
2696 /* Internal ioctl function */
2697 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2698 {
2699         int timeout;
2700         long ltmp;
2701         int ioctl_result;
2702         int chg_eof = 1;
2703         unsigned char cmd[MAX_COMMAND_SIZE];
2704         struct st_request *SRpnt;
2705         struct st_partstat *STps;
2706         int fileno, blkno, at_sm, undone;
2707         int datalen = 0, direction = DMA_NONE;
2708
2709         WARN_ON(STp->buffer->do_dio != 0);
2710         if (STp->ready != ST_READY) {
2711                 if (STp->ready == ST_NO_TAPE)
2712                         return (-ENOMEDIUM);
2713                 else
2714                         return (-EIO);
2715         }
2716         timeout = STp->long_timeout;
2717         STps = &(STp->ps[STp->partition]);
2718         fileno = STps->drv_file;
2719         blkno = STps->drv_block;
2720         at_sm = STps->at_sm;
2721
2722         memset(cmd, 0, MAX_COMMAND_SIZE);
2723         switch (cmd_in) {
2724         case MTFSFM:
2725                 chg_eof = 0;    /* Changed from the FSF after this */
2726                 fallthrough;
2727         case MTFSF:
2728                 cmd[0] = SPACE;
2729                 cmd[1] = 0x01;  /* Space FileMarks */
2730                 cmd[2] = (arg >> 16);
2731                 cmd[3] = (arg >> 8);
2732                 cmd[4] = arg;
2733                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2734                 if (fileno >= 0)
2735                         fileno += arg;
2736                 blkno = 0;
2737                 at_sm &= (arg == 0);
2738                 break;
2739         case MTBSFM:
2740                 chg_eof = 0;    /* Changed from the FSF after this */
2741                 fallthrough;
2742         case MTBSF:
2743                 cmd[0] = SPACE;
2744                 cmd[1] = 0x01;  /* Space FileMarks */
2745                 ltmp = (-arg);
2746                 cmd[2] = (ltmp >> 16);
2747                 cmd[3] = (ltmp >> 8);
2748                 cmd[4] = ltmp;
2749                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2750                 if (fileno >= 0)
2751                         fileno -= arg;
2752                 blkno = (-1);   /* We can't know the block number */
2753                 at_sm &= (arg == 0);
2754                 break;
2755         case MTFSR:
2756                 cmd[0] = SPACE;
2757                 cmd[1] = 0x00;  /* Space Blocks */
2758                 cmd[2] = (arg >> 16);
2759                 cmd[3] = (arg >> 8);
2760                 cmd[4] = arg;
2761                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2762                 if (blkno >= 0)
2763                         blkno += arg;
2764                 at_sm &= (arg == 0);
2765                 break;
2766         case MTBSR:
2767                 cmd[0] = SPACE;
2768                 cmd[1] = 0x00;  /* Space Blocks */
2769                 ltmp = (-arg);
2770                 cmd[2] = (ltmp >> 16);
2771                 cmd[3] = (ltmp >> 8);
2772                 cmd[4] = ltmp;
2773                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2774                 if (blkno >= 0)
2775                         blkno -= arg;
2776                 at_sm &= (arg == 0);
2777                 break;
2778         case MTFSS:
2779                 cmd[0] = SPACE;
2780                 cmd[1] = 0x04;  /* Space Setmarks */
2781                 cmd[2] = (arg >> 16);
2782                 cmd[3] = (arg >> 8);
2783                 cmd[4] = arg;
2784                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2785                 if (arg != 0) {
2786                         blkno = fileno = (-1);
2787                         at_sm = 1;
2788                 }
2789                 break;
2790         case MTBSS:
2791                 cmd[0] = SPACE;
2792                 cmd[1] = 0x04;  /* Space Setmarks */
2793                 ltmp = (-arg);
2794                 cmd[2] = (ltmp >> 16);
2795                 cmd[3] = (ltmp >> 8);
2796                 cmd[4] = ltmp;
2797                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2798                 if (arg != 0) {
2799                         blkno = fileno = (-1);
2800                         at_sm = 1;
2801                 }
2802                 break;
2803         case MTWEOF:
2804         case MTWEOFI:
2805         case MTWSM:
2806                 if (STp->write_prot)
2807                         return (-EACCES);
2808                 cmd[0] = WRITE_FILEMARKS;
2809                 if (cmd_in == MTWSM)
2810                         cmd[1] = 2;
2811                 if (cmd_in == MTWEOFI ||
2812                     (cmd_in == MTWEOF && STp->immediate_filemark))
2813                         cmd[1] |= 1;
2814                 cmd[2] = (arg >> 16);
2815                 cmd[3] = (arg >> 8);
2816                 cmd[4] = arg;
2817                 timeout = STp->device->request_queue->rq_timeout;
2818                 DEBC(
2819                         if (cmd_in != MTWSM)
2820                                 st_printk(ST_DEB_MSG, STp,
2821                                           "Writing %d filemarks.\n",
2822                                           cmd[2] * 65536 +
2823                                           cmd[3] * 256 +
2824                                           cmd[4]);
2825                         else
2826                                 st_printk(ST_DEB_MSG, STp,
2827                                           "Writing %d setmarks.\n",
2828                                           cmd[2] * 65536 +
2829                                           cmd[3] * 256 +
2830                                           cmd[4]);
2831                 )
2832                 if (fileno >= 0)
2833                         fileno += arg;
2834                 blkno = 0;
2835                 at_sm = (cmd_in == MTWSM);
2836                 break;
2837         case MTREW:
2838                 cmd[0] = REZERO_UNIT;
2839                 if (STp->immediate) {
2840                         cmd[1] = 1;     /* Don't wait for completion */
2841                         timeout = STp->device->request_queue->rq_timeout;
2842                 }
2843                 DEBC_printk(STp, "Rewinding tape.\n");
2844                 fileno = blkno = at_sm = 0;
2845                 break;
2846         case MTNOP:
2847                 DEBC_printk(STp, "No op on tape.\n");
2848                 return 0;       /* Should do something ? */
2849         case MTRETEN:
2850                 cmd[0] = START_STOP;
2851                 if (STp->immediate) {
2852                         cmd[1] = 1;     /* Don't wait for completion */
2853                         timeout = STp->device->request_queue->rq_timeout;
2854                 }
2855                 cmd[4] = 3;
2856                 DEBC_printk(STp, "Retensioning tape.\n");
2857                 fileno = blkno = at_sm = 0;
2858                 break;
2859         case MTEOM:
2860                 if (!STp->fast_mteom) {
2861                         /* space to the end of tape */
2862                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2863                         fileno = STps->drv_file;
2864                         if (STps->eof >= ST_EOD_1)
2865                                 return 0;
2866                         /* The next lines would hide the number of spaced FileMarks
2867                            That's why I inserted the previous lines. I had no luck
2868                            with detecting EOM with FSF, so we go now to EOM.
2869                            Joerg Weule */
2870                 } else
2871                         fileno = (-1);
2872                 cmd[0] = SPACE;
2873                 cmd[1] = 3;
2874                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2875                 blkno = -1;
2876                 at_sm = 0;
2877                 break;
2878         case MTERASE:
2879                 if (STp->write_prot)
2880                         return (-EACCES);
2881                 cmd[0] = ERASE;
2882                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2883                 if (STp->immediate) {
2884                         cmd[1] |= 2;    /* Don't wait for completion */
2885                         timeout = STp->device->request_queue->rq_timeout;
2886                 }
2887                 else
2888                         timeout = STp->long_timeout * 8;
2889
2890                 DEBC_printk(STp, "Erasing tape.\n");
2891                 fileno = blkno = at_sm = 0;
2892                 break;
2893         case MTSETBLK:          /* Set block length */
2894         case MTSETDENSITY:      /* Set tape density */
2895         case MTSETDRVBUFFER:    /* Set drive buffering */
2896         case SET_DENS_AND_BLK:  /* Set density and block size */
2897                 chg_eof = 0;
2898                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2899                         return (-EIO);  /* Not allowed if data in buffer */
2900                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2901                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2902                     STp->max_block > 0 &&
2903                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2904                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2905                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2906                         return (-EINVAL);
2907                 }
2908                 cmd[0] = MODE_SELECT;
2909                 if ((STp->use_pf & USE_PF))
2910                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2911                 cmd[4] = datalen = 12;
2912                 direction = DMA_TO_DEVICE;
2913
2914                 memset((STp->buffer)->b_data, 0, 12);
2915                 if (cmd_in == MTSETDRVBUFFER)
2916                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2917                 else
2918                         (STp->buffer)->b_data[2] =
2919                             STp->drv_buffer << 4;
2920                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2921                 if (cmd_in == MTSETDENSITY) {
2922                         (STp->buffer)->b_data[4] = arg;
2923                         STp->density_changed = 1;       /* At least we tried ;-) */
2924                 } else if (cmd_in == SET_DENS_AND_BLK)
2925                         (STp->buffer)->b_data[4] = arg >> 24;
2926                 else
2927                         (STp->buffer)->b_data[4] = STp->density;
2928                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2929                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2930                         if (cmd_in == MTSETBLK)
2931                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2932                 } else
2933                         ltmp = STp->block_size;
2934                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2935                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2936                 (STp->buffer)->b_data[11] = ltmp;
2937                 timeout = STp->device->request_queue->rq_timeout;
2938                 DEBC(
2939                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2940                                 st_printk(ST_DEB_MSG, STp,
2941                                           "Setting block size to %d bytes.\n",
2942                                           (STp->buffer)->b_data[9] * 65536 +
2943                                           (STp->buffer)->b_data[10] * 256 +
2944                                           (STp->buffer)->b_data[11]);
2945                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2946                                 st_printk(ST_DEB_MSG, STp,
2947                                           "Setting density code to %x.\n",
2948                                           (STp->buffer)->b_data[4]);
2949                         if (cmd_in == MTSETDRVBUFFER)
2950                                 st_printk(ST_DEB_MSG, STp,
2951                                           "Setting drive buffer code to %d.\n",
2952                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2953                 )
2954                 break;
2955         default:
2956                 return (-ENOSYS);
2957         }
2958
2959         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2960                            timeout, MAX_RETRIES, 1);
2961         if (!SRpnt)
2962                 return (STp->buffer)->syscall_result;
2963
2964         ioctl_result = (STp->buffer)->syscall_result;
2965
2966         if (!ioctl_result) {    /* SCSI command successful */
2967                 st_release_request(SRpnt);
2968                 SRpnt = NULL;
2969                 STps->drv_block = blkno;
2970                 STps->drv_file = fileno;
2971                 STps->at_sm = at_sm;
2972
2973                 if (cmd_in == MTBSFM)
2974                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2975                 else if (cmd_in == MTFSFM)
2976                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2977
2978                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2979                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2980                         if (STp->block_size != 0) {
2981                                 (STp->buffer)->buffer_blocks =
2982                                     (STp->buffer)->buffer_size / STp->block_size;
2983                         }
2984                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2985                         if (cmd_in == SET_DENS_AND_BLK)
2986                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2987                 } else if (cmd_in == MTSETDRVBUFFER)
2988                         STp->drv_buffer = (arg & 7);
2989                 else if (cmd_in == MTSETDENSITY)
2990                         STp->density = arg;
2991
2992                 if (cmd_in == MTEOM)
2993                         STps->eof = ST_EOD;
2994                 else if (cmd_in == MTFSF)
2995                         STps->eof = ST_FM;
2996                 else if (chg_eof)
2997                         STps->eof = ST_NOEOF;
2998
2999                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3000                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3001         } else { /* SCSI command was not completely successful. Don't return
3002                     from this block without releasing the SCSI command block! */
3003                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3004
3005                 if (cmdstatp->flags & SENSE_EOM) {
3006                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3007                             cmd_in != MTBSR && cmd_in != MTBSS)
3008                                 STps->eof = ST_EOM_OK;
3009                         STps->drv_block = 0;
3010                 }
3011
3012                 if (cmdstatp->remainder_valid)
3013                         undone = (int)cmdstatp->uremainder64;
3014                 else
3015                         undone = 0;
3016
3017                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3018                     cmdstatp->have_sense &&
3019                     (cmdstatp->flags & SENSE_EOM)) {
3020                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3021                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3022                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3023                                 STps->eof = ST_NOEOF;
3024                         } else {  /* Writing EOF(s) failed */
3025                                 if (fileno >= 0)
3026                                         fileno -= undone;
3027                                 if (undone < arg)
3028                                         STps->eof = ST_NOEOF;
3029                         }
3030                         STps->drv_file = fileno;
3031                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3032                         if (fileno >= 0)
3033                                 STps->drv_file = fileno - undone;
3034                         else
3035                                 STps->drv_file = fileno;
3036                         STps->drv_block = -1;
3037                         STps->eof = ST_NOEOF;
3038                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3039                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3040                                 undone = (-undone);
3041                         if (STps->drv_file >= 0)
3042                                 STps->drv_file = fileno + undone;
3043                         STps->drv_block = 0;
3044                         STps->eof = ST_NOEOF;
3045                 } else if (cmd_in == MTFSR) {
3046                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3047                                 if (STps->drv_file >= 0)
3048                                         STps->drv_file++;
3049                                 STps->drv_block = 0;
3050                                 STps->eof = ST_FM;
3051                         } else {
3052                                 if (blkno >= undone)
3053                                         STps->drv_block = blkno - undone;
3054                                 else
3055                                         STps->drv_block = (-1);
3056                                 STps->eof = ST_NOEOF;
3057                         }
3058                 } else if (cmd_in == MTBSR) {
3059                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3060                                 STps->drv_file--;
3061                                 STps->drv_block = (-1);
3062                         } else {
3063                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3064                                         undone = (-undone);
3065                                 if (STps->drv_block >= 0)
3066                                         STps->drv_block = blkno + undone;
3067                         }
3068                         STps->eof = ST_NOEOF;
3069                 } else if (cmd_in == MTEOM) {
3070                         STps->drv_file = (-1);
3071                         STps->drv_block = (-1);
3072                         STps->eof = ST_EOD;
3073                 } else if (cmd_in == MTSETBLK ||
3074                            cmd_in == MTSETDENSITY ||
3075                            cmd_in == MTSETDRVBUFFER ||
3076                            cmd_in == SET_DENS_AND_BLK) {
3077                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3078                             !(STp->use_pf & PF_TESTED)) {
3079                                 /* Try the other possible state of Page Format if not
3080                                    already tried */
3081                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3082                                 st_release_request(SRpnt);
3083                                 SRpnt = NULL;
3084                                 return st_int_ioctl(STp, cmd_in, arg);
3085                         }
3086                 } else if (chg_eof)
3087                         STps->eof = ST_NOEOF;
3088
3089                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3090                         STps->eof = ST_EOD;
3091
3092                 st_release_request(SRpnt);
3093                 SRpnt = NULL;
3094         }
3095
3096         return ioctl_result;
3097 }
3098 \f
3099
3100 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3101    structure. */
3102
3103 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3104                         int logical)
3105 {
3106         int result;
3107         unsigned char scmd[MAX_COMMAND_SIZE];
3108         struct st_request *SRpnt;
3109
3110         if (STp->ready != ST_READY)
3111                 return (-EIO);
3112
3113         memset(scmd, 0, MAX_COMMAND_SIZE);
3114         if ((STp->device)->scsi_level < SCSI_2) {
3115                 scmd[0] = QFA_REQUEST_BLOCK;
3116                 scmd[4] = 3;
3117         } else {
3118                 scmd[0] = READ_POSITION;
3119                 if (!logical && !STp->scsi2_logical)
3120                         scmd[1] = 1;
3121         }
3122         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3123                            STp->device->request_queue->rq_timeout,
3124                            MAX_READY_RETRIES, 1);
3125         if (!SRpnt)
3126                 return (STp->buffer)->syscall_result;
3127
3128         if ((STp->buffer)->syscall_result != 0 ||
3129             (STp->device->scsi_level >= SCSI_2 &&
3130              ((STp->buffer)->b_data[0] & 4) != 0)) {
3131                 *block = *partition = 0;
3132                 DEBC_printk(STp, " Can't read tape position.\n");
3133                 result = (-EIO);
3134         } else {
3135                 result = 0;
3136                 if ((STp->device)->scsi_level < SCSI_2) {
3137                         *block = ((STp->buffer)->b_data[0] << 16)
3138                             + ((STp->buffer)->b_data[1] << 8)
3139                             + (STp->buffer)->b_data[2];
3140                         *partition = 0;
3141                 } else {
3142                         *block = ((STp->buffer)->b_data[4] << 24)
3143                             + ((STp->buffer)->b_data[5] << 16)
3144                             + ((STp->buffer)->b_data[6] << 8)
3145                             + (STp->buffer)->b_data[7];
3146                         *partition = (STp->buffer)->b_data[1];
3147                         if (((STp->buffer)->b_data[0] & 0x80) &&
3148                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3149                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3150                 }
3151                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3152                             *block, *partition);
3153         }
3154         st_release_request(SRpnt);
3155         SRpnt = NULL;
3156
3157         return result;
3158 }
3159
3160
3161 /* Set the tape block and partition. Negative partition means that only the
3162    block should be set in vendor specific way. */
3163 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3164                         int logical)
3165 {
3166         struct st_partstat *STps;
3167         int result, p;
3168         unsigned int blk;
3169         int timeout;
3170         unsigned char scmd[MAX_COMMAND_SIZE];
3171         struct st_request *SRpnt;
3172
3173         if (STp->ready != ST_READY)
3174                 return (-EIO);
3175         timeout = STp->long_timeout;
3176         STps = &(STp->ps[STp->partition]);
3177
3178         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3179                     block, partition);
3180         DEB(if (partition < 0)
3181                 return (-EIO); )
3182
3183         /* Update the location at the partition we are leaving */
3184         if ((!STp->can_partitions && partition != 0) ||
3185             partition >= ST_NBR_PARTITIONS)
3186                 return (-EINVAL);
3187         if (partition != STp->partition) {
3188                 if (get_location(STp, &blk, &p, 1))
3189                         STps->last_block_valid = 0;
3190                 else {
3191                         STps->last_block_valid = 1;
3192                         STps->last_block_visited = blk;
3193                         DEBC_printk(STp, "Visited block %d for "
3194                                     "partition %d saved.\n",
3195                                     blk, STp->partition);
3196                 }
3197         }
3198
3199         memset(scmd, 0, MAX_COMMAND_SIZE);
3200         if ((STp->device)->scsi_level < SCSI_2) {
3201                 scmd[0] = QFA_SEEK_BLOCK;
3202                 scmd[2] = (block >> 16);
3203                 scmd[3] = (block >> 8);
3204                 scmd[4] = block;
3205                 scmd[5] = 0;
3206         } else {
3207                 scmd[0] = SEEK_10;
3208                 scmd[3] = (block >> 24);
3209                 scmd[4] = (block >> 16);
3210                 scmd[5] = (block >> 8);
3211                 scmd[6] = block;
3212                 if (!logical && !STp->scsi2_logical)
3213                         scmd[1] = 4;
3214                 if (STp->partition != partition) {
3215                         scmd[1] |= 2;
3216                         scmd[8] = partition;
3217                         DEBC_printk(STp, "Trying to change partition "
3218                                     "from %d to %d\n", STp->partition,
3219                                     partition);
3220                 }
3221         }
3222         if (STp->immediate) {
3223                 scmd[1] |= 1;           /* Don't wait for completion */
3224                 timeout = STp->device->request_queue->rq_timeout;
3225         }
3226
3227         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3228                            timeout, MAX_READY_RETRIES, 1);
3229         if (!SRpnt)
3230                 return (STp->buffer)->syscall_result;
3231
3232         STps->drv_block = STps->drv_file = (-1);
3233         STps->eof = ST_NOEOF;
3234         if ((STp->buffer)->syscall_result != 0) {
3235                 result = (-EIO);
3236                 if (STp->can_partitions &&
3237                     (STp->device)->scsi_level >= SCSI_2 &&
3238                     (p = find_partition(STp)) >= 0)
3239                         STp->partition = p;
3240         } else {
3241                 if (STp->can_partitions) {
3242                         STp->partition = partition;
3243                         STps = &(STp->ps[partition]);
3244                         if (!STps->last_block_valid ||
3245                             STps->last_block_visited != block) {
3246                                 STps->at_sm = 0;
3247                                 STps->rw = ST_IDLE;
3248                         }
3249                 } else
3250                         STps->at_sm = 0;
3251                 if (block == 0)
3252                         STps->drv_block = STps->drv_file = 0;
3253                 result = 0;
3254         }
3255
3256         st_release_request(SRpnt);
3257         SRpnt = NULL;
3258
3259         return result;
3260 }
3261
3262
3263 /* Find the current partition number for the drive status. Called from open and
3264    returns either partition number of negative error code. */
3265 static int find_partition(struct scsi_tape *STp)
3266 {
3267         int i, partition;
3268         unsigned int block;
3269
3270         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3271                 return i;
3272         if (partition >= ST_NBR_PARTITIONS)
3273                 return (-EIO);
3274         return partition;
3275 }
3276
3277
3278 /* Change the partition if necessary */
3279 static int switch_partition(struct scsi_tape *STp)
3280 {
3281         struct st_partstat *STps;
3282
3283         if (STp->partition == STp->new_partition)
3284                 return 0;
3285         STps = &(STp->ps[STp->new_partition]);
3286         if (!STps->last_block_valid)
3287                 STps->last_block_visited = 0;
3288         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3289 }
3290 \f
3291 /* Functions for reading and writing the medium partition mode page. */
3292
3293 #define PART_PAGE   0x11
3294 #define PART_PAGE_FIXED_LENGTH 8
3295
3296 #define PP_OFF_MAX_ADD_PARTS   2
3297 #define PP_OFF_NBR_ADD_PARTS   3
3298 #define PP_OFF_FLAGS           4
3299 #define PP_OFF_PART_UNITS      6
3300 #define PP_OFF_RESERVED        7
3301
3302 #define PP_BIT_IDP             0x20
3303 #define PP_BIT_FDP             0x80
3304 #define PP_MSK_PSUM_MB         0x10
3305 #define PP_MSK_PSUM_UNITS      0x18
3306 #define PP_MSK_POFM            0x04
3307
3308 /* Get the number of partitions on the tape. As a side effect reads the
3309    mode page into the tape buffer. */
3310 static int nbr_partitions(struct scsi_tape *STp)
3311 {
3312         int result;
3313
3314         if (STp->ready != ST_READY)
3315                 return (-EIO);
3316
3317         result = read_mode_page(STp, PART_PAGE, 1);
3318
3319         if (result) {
3320                 DEBC_printk(STp, "Can't read medium partition page.\n");
3321                 result = (-EIO);
3322         } else {
3323                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3324                                               PP_OFF_NBR_ADD_PARTS] + 1;
3325                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3326         }
3327
3328         return result;
3329 }
3330
3331
3332 static int format_medium(struct scsi_tape *STp, int format)
3333 {
3334         int result = 0;
3335         int timeout = STp->long_timeout;
3336         unsigned char scmd[MAX_COMMAND_SIZE];
3337         struct st_request *SRpnt;
3338
3339         memset(scmd, 0, MAX_COMMAND_SIZE);
3340         scmd[0] = FORMAT_UNIT;
3341         scmd[2] = format;
3342         if (STp->immediate) {
3343                 scmd[1] |= 1;           /* Don't wait for completion */
3344                 timeout = STp->device->request_queue->rq_timeout;
3345         }
3346         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3347         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3348                            timeout, MAX_RETRIES, 1);
3349         if (!SRpnt)
3350                 result = STp->buffer->syscall_result;
3351         return result;
3352 }
3353
3354
3355 /* Partition the tape into two partitions if size > 0 or one partition if
3356    size == 0.
3357
3358    The block descriptors are read and written because Sony SDT-7000 does not
3359    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3360
3361    My HP C1533A drive returns only one partition size field. This is used to
3362    set the size of partition 1. There is no size field for the default partition.
3363    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3364    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3365    The following algorithm is used to accommodate both drives: if the number of
3366    partition size fields is greater than the maximum number of additional partitions
3367    in the mode page, the second field is used. Otherwise the first field is used.
3368
3369    For Seagate DDS drives the page length must be 8 when no partitions is defined
3370    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3371    is acceptable also to some other old drives and enforced if the first partition
3372    size field is used for the first additional partition size.
3373
3374    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3375  */
3376 static int partition_tape(struct scsi_tape *STp, int size)
3377 {
3378         int result;
3379         int target_partition;
3380         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3381         int pgo, psd_cnt, psdo;
3382         int psum = PP_MSK_PSUM_MB, units = 0;
3383         unsigned char *bp;
3384
3385         result = read_mode_page(STp, PART_PAGE, 0);
3386         if (result) {
3387                 DEBC_printk(STp, "Can't read partition mode page.\n");
3388                 return result;
3389         }
3390         target_partition = 1;
3391         if (size < 0) {
3392                 target_partition = 0;
3393                 size = -size;
3394         }
3395
3396         /* The mode page is in the buffer. Let's modify it and write it. */
3397         bp = (STp->buffer)->b_data;
3398         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3399         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3400                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3401
3402         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3403
3404         if (scsi3) {
3405                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3406                 if (needs_format && size == 0) {
3407                         /* No need to write the mode page when clearing
3408                          *  partitioning
3409                          */
3410                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3411                         result = format_medium(STp, 0);
3412                         goto out;
3413                 }
3414                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3415                         psd_cnt = 2;
3416                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3417                         /* Use units scaling for large partitions if the device
3418                          * suggests it and no precision lost. Required for IBM
3419                          * TS1140/50 drives that don't support MB units.
3420                          */
3421                         if (size >= 1000 && (size % 1000) == 0) {
3422                                 size /= 1000;
3423                                 psum = PP_MSK_PSUM_UNITS;
3424                                 units = 9; /* GB */
3425                         }
3426                 }
3427                 /* Try it anyway if too large to specify in MB */
3428                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3429                         size /= 1000;
3430                         psum = PP_MSK_PSUM_UNITS;
3431                         units = 9;  /* GB */
3432                 }
3433         }
3434
3435         if (size >= 65535 ||  /* Does not fit into two bytes */
3436             (target_partition == 0 && psd_cnt < 2)) {
3437                 result = -EINVAL;
3438                 goto out;
3439         }
3440
3441         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3442         /* The second condition is for HP DDS which use only one partition size
3443          * descriptor
3444          */
3445         if (target_partition > 0 &&
3446             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3447              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3448                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3449                 psdo += 2;
3450         }
3451         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3452
3453         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3454                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3455                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3456
3457         if (size == 0) {
3458                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3459                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3460                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3461                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3462         } else {
3463                 bp[psdo] = (size >> 8) & 0xff;
3464                 bp[psdo + 1] = size & 0xff;
3465                 if (target_partition == 0)
3466                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3467                 bp[pgo + 3] = 1;
3468                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3469                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3470                 DEBC_printk(STp,
3471                             "Formatting tape with two partitions (%i = %d MB).\n",
3472                             target_partition, units > 0 ? size * 1000 : size);
3473         }
3474         bp[pgo + PP_OFF_PART_UNITS] = 0;
3475         bp[pgo + PP_OFF_RESERVED] = 0;
3476         if (size != 1 || units != 0) {
3477                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3478                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3479                 bp[pgo + PP_OFF_PART_UNITS] = units;
3480         } else
3481                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3482                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3483         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3484
3485         result = write_mode_page(STp, PART_PAGE, 1);
3486
3487         if (!result && needs_format)
3488                 result = format_medium(STp, 1);
3489
3490         if (result) {
3491                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3492                 result = (-EIO);
3493         }
3494
3495 out:
3496         return result;
3497 }
3498 \f
3499
3500
3501 /* The ioctl command */
3502 static long st_ioctl_common(struct file *file, unsigned int cmd_in, void __user *p)
3503 {
3504         int i, cmd_nr, cmd_type, bt;
3505         int retval = 0;
3506         unsigned int blk;
3507         struct scsi_tape *STp = file->private_data;
3508         struct st_modedef *STm;
3509         struct st_partstat *STps;
3510
3511         if (mutex_lock_interruptible(&STp->lock))
3512                 return -ERESTARTSYS;
3513
3514         DEB(
3515         if (debugging && !STp->in_use) {
3516                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3517                 retval = (-EIO);
3518                 goto out;
3519         } ) /* end DEB */
3520
3521         STm = &(STp->modes[STp->current_mode]);
3522         STps = &(STp->ps[STp->partition]);
3523
3524         /*
3525          * If we are in the middle of error recovery, don't let anyone
3526          * else try and use this device.  Also, if error recovery fails, it
3527          * may try and take the device offline, in which case all further
3528          * access to the device is prohibited.
3529          */
3530         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3531                         file->f_flags & O_NDELAY);
3532         if (retval)
3533                 goto out;
3534
3535         cmd_type = _IOC_TYPE(cmd_in);
3536         cmd_nr = _IOC_NR(cmd_in);
3537
3538         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3539                 struct mtop mtc;
3540
3541                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3542                         retval = (-EINVAL);
3543                         goto out;
3544                 }
3545
3546                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3547                 if (i) {
3548                         retval = (-EFAULT);
3549                         goto out;
3550                 }
3551
3552                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3553                         st_printk(KERN_WARNING, STp,
3554                                   "MTSETDRVBUFFER only allowed for root.\n");
3555                         retval = (-EPERM);
3556                         goto out;
3557                 }
3558                 if (!STm->defined &&
3559                     (mtc.mt_op != MTSETDRVBUFFER &&
3560                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3561                         retval = (-ENXIO);
3562                         goto out;
3563                 }
3564
3565                 if (!STp->pos_unknown) {
3566
3567                         if (STps->eof == ST_FM_HIT) {
3568                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3569                                     mtc.mt_op == MTEOM) {
3570                                         mtc.mt_count -= 1;
3571                                         if (STps->drv_file >= 0)
3572                                                 STps->drv_file += 1;
3573                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3574                                         mtc.mt_count += 1;
3575                                         if (STps->drv_file >= 0)
3576                                                 STps->drv_file += 1;
3577                                 }
3578                         }
3579
3580                         if (mtc.mt_op == MTSEEK) {
3581                                 /* Old position must be restored if partition will be
3582                                    changed */
3583                                 i = !STp->can_partitions ||
3584                                     (STp->new_partition != STp->partition);
3585                         } else {
3586                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3587                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3588                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3589                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3590                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3591                                     mtc.mt_op == MTCOMPRESSION;
3592                         }
3593                         i = flush_buffer(STp, i);
3594                         if (i < 0) {
3595                                 retval = i;
3596                                 goto out;
3597                         }
3598                         if (STps->rw == ST_WRITING &&
3599                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3600                              mtc.mt_op == MTSEEK ||
3601                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3602                                 i = st_int_ioctl(STp, MTWEOF, 1);
3603                                 if (i < 0) {
3604                                         retval = i;
3605                                         goto out;
3606                                 }
3607                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3608                                         mtc.mt_count++;
3609                                 STps->rw = ST_IDLE;
3610                              }
3611
3612                 } else {
3613                         /*
3614                          * If there was a bus reset, block further access
3615                          * to this device.  If the user wants to rewind the tape,
3616                          * then reset the flag and allow access again.
3617                          */
3618                         if (mtc.mt_op != MTREW &&
3619                             mtc.mt_op != MTOFFL &&
3620                             mtc.mt_op != MTRETEN &&
3621                             mtc.mt_op != MTERASE &&
3622                             mtc.mt_op != MTSEEK &&
3623                             mtc.mt_op != MTEOM) {
3624                                 retval = (-EIO);
3625                                 goto out;
3626                         }
3627                         reset_state(STp);
3628                         /* remove this when the midlevel properly clears was_reset */
3629                         STp->device->was_reset = 0;
3630                 }
3631
3632                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3633                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3634                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3635                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3636
3637                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3638                         do_door_lock(STp, 0);   /* Ignore result! */
3639
3640                 if (mtc.mt_op == MTSETDRVBUFFER &&
3641                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3642                         retval = st_set_options(STp, mtc.mt_count);
3643                         goto out;
3644                 }
3645
3646                 if (mtc.mt_op == MTSETPART) {
3647                         if (!STp->can_partitions ||
3648                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3649                                 retval = (-EINVAL);
3650                                 goto out;
3651                         }
3652                         if (mtc.mt_count >= STp->nbr_partitions &&
3653                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3654                                 retval = (-EIO);
3655                                 goto out;
3656                         }
3657                         if (mtc.mt_count >= STp->nbr_partitions) {
3658                                 retval = (-EINVAL);
3659                                 goto out;
3660                         }
3661                         STp->new_partition = mtc.mt_count;
3662                         retval = 0;
3663                         goto out;
3664                 }
3665
3666                 if (mtc.mt_op == MTMKPART) {
3667                         if (!STp->can_partitions) {
3668                                 retval = (-EINVAL);
3669                                 goto out;
3670                         }
3671                         i = do_load_unload(STp, file, 1);
3672                         if (i < 0) {
3673                                 retval = i;
3674                                 goto out;
3675                         }
3676                         i = partition_tape(STp, mtc.mt_count);
3677                         if (i < 0) {
3678                                 retval = i;
3679                                 goto out;
3680                         }
3681                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3682                                 STp->ps[i].rw = ST_IDLE;
3683                                 STp->ps[i].at_sm = 0;
3684                                 STp->ps[i].last_block_valid = 0;
3685                         }
3686                         STp->partition = STp->new_partition = 0;
3687                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3688                         STps->drv_block = STps->drv_file = 0;
3689                         retval = 0;
3690                         goto out;
3691                 }
3692
3693                 if (mtc.mt_op == MTSEEK) {
3694                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3695                         if (!STp->can_partitions)
3696                                 STp->ps[0].rw = ST_IDLE;
3697                         retval = i;
3698                         goto out;
3699                 }
3700
3701                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3702                         retval = do_load_unload(STp, file, 0);
3703                         goto out;
3704                 }
3705
3706                 if (mtc.mt_op == MTLOAD) {
3707                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3708                         goto out;
3709                 }
3710
3711                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3712                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3713                         goto out;
3714                 }
3715
3716                 if (STp->can_partitions && STp->ready == ST_READY &&
3717                     (i = switch_partition(STp)) < 0) {
3718                         retval = i;
3719                         goto out;
3720                 }
3721
3722                 if (mtc.mt_op == MTCOMPRESSION)
3723                         retval = st_compression(STp, (mtc.mt_count & 1));
3724                 else
3725                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3726                 goto out;
3727         }
3728         if (!STm->defined) {
3729                 retval = (-ENXIO);
3730                 goto out;
3731         }
3732
3733         if ((i = flush_buffer(STp, 0)) < 0) {
3734                 retval = i;
3735                 goto out;
3736         }
3737         if (STp->can_partitions &&
3738             (i = switch_partition(STp)) < 0) {
3739                 retval = i;
3740                 goto out;
3741         }
3742
3743         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3744                 struct mtget mt_status;
3745
3746                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3747                          retval = (-EINVAL);
3748                          goto out;
3749                 }
3750
3751                 mt_status.mt_type = STp->tape_type;
3752                 mt_status.mt_dsreg =
3753                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3754                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3755                 mt_status.mt_blkno = STps->drv_block;
3756                 mt_status.mt_fileno = STps->drv_file;
3757                 if (STp->block_size != 0) {
3758                         if (STps->rw == ST_WRITING)
3759                                 mt_status.mt_blkno +=
3760                                     (STp->buffer)->buffer_bytes / STp->block_size;
3761                         else if (STps->rw == ST_READING)
3762                                 mt_status.mt_blkno -=
3763                                         ((STp->buffer)->buffer_bytes +
3764                                          STp->block_size - 1) / STp->block_size;
3765                 }
3766
3767                 mt_status.mt_gstat = 0;
3768                 if (STp->drv_write_prot)
3769                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3770                 if (mt_status.mt_blkno == 0) {
3771                         if (mt_status.mt_fileno == 0)
3772                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3773                         else
3774                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3775                 }
3776                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3777                 mt_status.mt_resid = STp->partition;
3778                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3779                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3780                 else if (STps->eof >= ST_EOM_OK)
3781                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3782                 if (STp->density == 1)
3783                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3784                 else if (STp->density == 2)
3785                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3786                 else if (STp->density == 3)
3787                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3788                 if (STp->ready == ST_READY)
3789                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3790                 if (STp->ready == ST_NO_TAPE)
3791                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3792                 if (STps->at_sm)
3793                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3794                 if (STm->do_async_writes ||
3795                     (STm->do_buffer_writes && STp->block_size != 0) ||
3796                     STp->drv_buffer != 0)
3797                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3798                 if (STp->cleaning_req)
3799                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3800
3801                 retval = put_user_mtget(p, &mt_status);
3802                 if (retval)
3803                         goto out;
3804
3805                 STp->recover_reg = 0;           /* Clear after read */
3806                 goto out;
3807         }                       /* End of MTIOCGET */
3808         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3809                 struct mtpos mt_pos;
3810                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3811                          retval = (-EINVAL);
3812                          goto out;
3813                 }
3814                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3815                         retval = i;
3816                         goto out;
3817                 }
3818                 mt_pos.mt_blkno = blk;
3819                 retval = put_user_mtpos(p, &mt_pos);
3820                 goto out;
3821         }
3822         mutex_unlock(&STp->lock);
3823         switch (cmd_in) {
3824                 case SCSI_IOCTL_STOP_UNIT:
3825                         /* unload */
3826                         retval = scsi_ioctl(STp->device, cmd_in, p);
3827                         if (!retval) {
3828                                 STp->rew_at_close = 0;
3829                                 STp->ready = ST_NO_TAPE;
3830                         }
3831                         return retval;
3832
3833                 case SCSI_IOCTL_GET_IDLUN:
3834                 case SCSI_IOCTL_GET_BUS_NUMBER:
3835                         break;
3836
3837                 default:
3838                         if ((cmd_in == SG_IO ||
3839                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3840                              cmd_in == CDROM_SEND_PACKET) &&
3841                             !capable(CAP_SYS_RAWIO))
3842                                 i = -EPERM;
3843                         else
3844                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3845                                                    file->f_mode, cmd_in, p);
3846                         if (i != -ENOTTY)
3847                                 return i;
3848                         break;
3849         }
3850         return -ENOTTY;
3851
3852  out:
3853         mutex_unlock(&STp->lock);
3854         return retval;
3855 }
3856
3857 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3858 {
3859         void __user *p = (void __user *)arg;
3860         struct scsi_tape *STp = file->private_data;
3861         int ret;
3862
3863         ret = st_ioctl_common(file, cmd_in, p);
3864         if (ret != -ENOTTY)
3865                 return ret;
3866
3867         return scsi_ioctl(STp->device, cmd_in, p);
3868 }
3869
3870 #ifdef CONFIG_COMPAT
3871 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3872 {
3873         void __user *p = compat_ptr(arg);
3874         struct scsi_tape *STp = file->private_data;
3875         int ret;
3876
3877         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3878         switch (cmd_in) {
3879         case MTIOCPOS32:
3880                 return st_ioctl_common(file, MTIOCPOS, p);
3881         case MTIOCGET32:
3882                 return st_ioctl_common(file, MTIOCGET, p);
3883         }
3884
3885         ret = st_ioctl_common(file, cmd_in, p);
3886         if (ret != -ENOTTY)
3887                 return ret;
3888
3889         return scsi_compat_ioctl(STp->device, cmd_in, p);
3890 }
3891 #endif
3892
3893 \f
3894
3895 /* Try to allocate a new tape buffer. Calling function must not hold
3896    dev_arr_lock. */
3897 static struct st_buffer *new_tape_buffer(int max_sg)
3898 {
3899         struct st_buffer *tb;
3900
3901         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3902         if (!tb) {
3903                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3904                 return NULL;
3905         }
3906         tb->frp_segs = 0;
3907         tb->use_sg = max_sg;
3908         tb->buffer_size = 0;
3909
3910         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3911                                      GFP_KERNEL);
3912         if (!tb->reserved_pages) {
3913                 kfree(tb);
3914                 return NULL;
3915         }
3916
3917         return tb;
3918 }
3919
3920
3921 /* Try to allocate enough space in the tape buffer */
3922 #define ST_MAX_ORDER 6
3923
3924 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size)
3925 {
3926         int segs, max_segs, b_size, order, got;
3927         gfp_t priority;
3928
3929         if (new_size <= STbuffer->buffer_size)
3930                 return 1;
3931
3932         if (STbuffer->buffer_size <= PAGE_SIZE)
3933                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3934
3935         max_segs = STbuffer->use_sg;
3936
3937         priority = GFP_KERNEL | __GFP_NOWARN;
3938
3939         if (STbuffer->cleared)
3940                 priority |= __GFP_ZERO;
3941
3942         if (STbuffer->frp_segs) {
3943                 order = STbuffer->reserved_page_order;
3944                 b_size = PAGE_SIZE << order;
3945         } else {
3946                 for (b_size = PAGE_SIZE, order = 0;
3947                      order < ST_MAX_ORDER &&
3948                              max_segs * (PAGE_SIZE << order) < new_size;
3949                      order++, b_size *= 2)
3950                         ;  /* empty */
3951                 STbuffer->reserved_page_order = order;
3952         }
3953         if (max_segs * (PAGE_SIZE << order) < new_size) {
3954                 if (order == ST_MAX_ORDER)
3955                         return 0;
3956                 normalize_buffer(STbuffer);
3957                 return enlarge_buffer(STbuffer, new_size);
3958         }
3959
3960         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3961              segs < max_segs && got < new_size;) {
3962                 struct page *page;
3963
3964                 page = alloc_pages(priority, order);
3965                 if (!page) {
3966                         DEB(STbuffer->buffer_size = got);
3967                         normalize_buffer(STbuffer);
3968                         return 0;
3969                 }
3970
3971                 STbuffer->frp_segs += 1;
3972                 got += b_size;
3973                 STbuffer->buffer_size = got;
3974                 STbuffer->reserved_pages[segs] = page;
3975                 segs++;
3976         }
3977         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3978
3979         return 1;
3980 }
3981
3982
3983 /* Make sure that no data from previous user is in the internal buffer */
3984 static void clear_buffer(struct st_buffer * st_bp)
3985 {
3986         int i;
3987
3988         for (i=0; i < st_bp->frp_segs; i++)
3989                 memset(page_address(st_bp->reserved_pages[i]), 0,
3990                        PAGE_SIZE << st_bp->reserved_page_order);
3991         st_bp->cleared = 1;
3992 }
3993
3994
3995 /* Release the extra buffer */
3996 static void normalize_buffer(struct st_buffer * STbuffer)
3997 {
3998         int i, order = STbuffer->reserved_page_order;
3999
4000         for (i = 0; i < STbuffer->frp_segs; i++) {
4001                 __free_pages(STbuffer->reserved_pages[i], order);
4002                 STbuffer->buffer_size -= (PAGE_SIZE << order);
4003         }
4004         STbuffer->frp_segs = 0;
4005         STbuffer->sg_segs = 0;
4006         STbuffer->reserved_page_order = 0;
4007         STbuffer->map_data.offset = 0;
4008 }
4009
4010
4011 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
4012    negative error code. */
4013 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
4014 {
4015         int i, cnt, res, offset;
4016         int length = PAGE_SIZE << st_bp->reserved_page_order;
4017
4018         for (i = 0, offset = st_bp->buffer_bytes;
4019              i < st_bp->frp_segs && offset >= length; i++)
4020                 offset -= length;
4021         if (i == st_bp->frp_segs) {     /* Should never happen */
4022                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4023                 return (-EIO);
4024         }
4025         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4026                 struct page *page = st_bp->reserved_pages[i];
4027                 cnt = length - offset < do_count ? length - offset : do_count;
4028                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4029                 if (res)
4030                         return (-EFAULT);
4031                 do_count -= cnt;
4032                 st_bp->buffer_bytes += cnt;
4033                 ubp += cnt;
4034                 offset = 0;
4035         }
4036         if (do_count) /* Should never happen */
4037                 return (-EIO);
4038
4039         return 0;
4040 }
4041
4042
4043 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4044    negative error code. */
4045 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4046 {
4047         int i, cnt, res, offset;
4048         int length = PAGE_SIZE << st_bp->reserved_page_order;
4049
4050         for (i = 0, offset = st_bp->read_pointer;
4051              i < st_bp->frp_segs && offset >= length; i++)
4052                 offset -= length;
4053         if (i == st_bp->frp_segs) {     /* Should never happen */
4054                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4055                 return (-EIO);
4056         }
4057         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4058                 struct page *page = st_bp->reserved_pages[i];
4059                 cnt = length - offset < do_count ? length - offset : do_count;
4060                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4061                 if (res)
4062                         return (-EFAULT);
4063                 do_count -= cnt;
4064                 st_bp->buffer_bytes -= cnt;
4065                 st_bp->read_pointer += cnt;
4066                 ubp += cnt;
4067                 offset = 0;
4068         }
4069         if (do_count) /* Should never happen */
4070                 return (-EIO);
4071
4072         return 0;
4073 }
4074
4075
4076 /* Move data towards start of buffer */
4077 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4078 {
4079         int src_seg, dst_seg, src_offset = 0, dst_offset;
4080         int count, total;
4081         int length = PAGE_SIZE << st_bp->reserved_page_order;
4082
4083         if (offset == 0)
4084                 return;
4085
4086         total=st_bp->buffer_bytes - offset;
4087         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4088                 src_offset = offset;
4089                 if (src_offset < length)
4090                         break;
4091                 offset -= length;
4092         }
4093
4094         st_bp->buffer_bytes = st_bp->read_pointer = total;
4095         for (dst_seg=dst_offset=0; total > 0; ) {
4096                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4097                 struct page *spage = st_bp->reserved_pages[src_seg];
4098
4099                 count = min(length - dst_offset, length - src_offset);
4100                 memmove(page_address(dpage) + dst_offset,
4101                         page_address(spage) + src_offset, count);
4102                 src_offset += count;
4103                 if (src_offset >= length) {
4104                         src_seg++;
4105                         src_offset = 0;
4106                 }
4107                 dst_offset += count;
4108                 if (dst_offset >= length) {
4109                         dst_seg++;
4110                         dst_offset = 0;
4111                 }
4112                 total -= count;
4113         }
4114 }
4115
4116 /* Validate the options from command line or module parameters */
4117 static void validate_options(void)
4118 {
4119         if (buffer_kbs > 0)
4120                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4121         if (max_sg_segs >= ST_FIRST_SG)
4122                 st_max_sg_segs = max_sg_segs;
4123 }
4124
4125 #ifndef MODULE
4126 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4127  */
4128 static int __init st_setup(char *str)
4129 {
4130         int i, len, ints[5];
4131         char *stp;
4132
4133         stp = get_options(str, ARRAY_SIZE(ints), ints);
4134
4135         if (ints[0] > 0) {
4136                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4137                         if (parms[i].val)
4138                                 *parms[i].val = ints[i + 1];
4139         } else {
4140                 while (stp != NULL) {
4141                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4142                                 len = strlen(parms[i].name);
4143                                 if (!strncmp(stp, parms[i].name, len) &&
4144                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4145                                         if (parms[i].val)
4146                                                 *parms[i].val =
4147                                                         simple_strtoul(stp + len + 1, NULL, 0);
4148                                         else
4149                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4150                                                        parms[i].name);
4151                                         break;
4152                                 }
4153                         }
4154                         if (i >= ARRAY_SIZE(parms))
4155                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4156                                         stp);
4157                         stp = strchr(stp, ',');
4158                         if (stp)
4159                                 stp++;
4160                 }
4161         }
4162
4163         validate_options();
4164
4165         return 1;
4166 }
4167
4168 __setup("st=", st_setup);
4169
4170 #endif
4171
4172 static const struct file_operations st_fops =
4173 {
4174         .owner =        THIS_MODULE,
4175         .read =         st_read,
4176         .write =        st_write,
4177         .unlocked_ioctl = st_ioctl,
4178 #ifdef CONFIG_COMPAT
4179         .compat_ioctl = st_compat_ioctl,
4180 #endif
4181         .open =         st_open,
4182         .flush =        st_flush,
4183         .release =      st_release,
4184         .llseek =       noop_llseek,
4185 };
4186
4187 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4188 {
4189         int i, error;
4190         dev_t cdev_devno;
4191         struct cdev *cdev;
4192         struct device *dev;
4193         struct st_modedef *STm = &(tape->modes[mode]);
4194         char name[10];
4195         int dev_num = tape->index;
4196
4197         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4198
4199         cdev = cdev_alloc();
4200         if (!cdev) {
4201                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4202                 error = -ENOMEM;
4203                 goto out;
4204         }
4205         cdev->owner = THIS_MODULE;
4206         cdev->ops = &st_fops;
4207         STm->cdevs[rew] = cdev;
4208
4209         error = cdev_add(cdev, cdev_devno, 1);
4210         if (error) {
4211                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4212                        rew ? "non" : "auto", mode);
4213                 pr_err("st%d: Device not attached.\n", dev_num);
4214                 goto out_free;
4215         }
4216
4217         i = mode << (4 - ST_NBR_MODE_BITS);
4218         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4219                  tape->disk->disk_name, st_formats[i]);
4220
4221         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4222                             cdev_devno, &tape->modes[mode], "%s", name);
4223         if (IS_ERR(dev)) {
4224                 pr_err("st%d: device_create failed\n", dev_num);
4225                 error = PTR_ERR(dev);
4226                 goto out_free;
4227         }
4228
4229         STm->devs[rew] = dev;
4230
4231         return 0;
4232 out_free:
4233         cdev_del(STm->cdevs[rew]);
4234 out:
4235         STm->cdevs[rew] = NULL;
4236         STm->devs[rew] = NULL;
4237         return error;
4238 }
4239
4240 static int create_cdevs(struct scsi_tape *tape)
4241 {
4242         int mode, error;
4243         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4244                 error = create_one_cdev(tape, mode, 0);
4245                 if (error)
4246                         return error;
4247                 error = create_one_cdev(tape, mode, 1);
4248                 if (error)
4249                         return error;
4250         }
4251
4252         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4253                                  &tape->modes[0].devs[0]->kobj, "tape");
4254 }
4255
4256 static void remove_cdevs(struct scsi_tape *tape)
4257 {
4258         int mode, rew;
4259         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4260         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4261                 struct st_modedef *STm = &(tape->modes[mode]);
4262                 for (rew = 0; rew < 2; rew++) {
4263                         if (STm->cdevs[rew])
4264                                 cdev_del(STm->cdevs[rew]);
4265                         if (STm->devs[rew])
4266                                 device_unregister(STm->devs[rew]);
4267                 }
4268         }
4269 }
4270
4271 static int st_probe(struct device *dev)
4272 {
4273         struct scsi_device *SDp = to_scsi_device(dev);
4274         struct gendisk *disk = NULL;
4275         struct scsi_tape *tpnt = NULL;
4276         struct st_modedef *STm;
4277         struct st_partstat *STps;
4278         struct st_buffer *buffer;
4279         int i, error;
4280         char *stp;
4281
4282         if (SDp->type != TYPE_TAPE)
4283                 return -ENODEV;
4284         if ((stp = st_incompatible(SDp))) {
4285                 sdev_printk(KERN_INFO, SDp,
4286                             "OnStream tapes are no longer supported;\n");
4287                 sdev_printk(KERN_INFO, SDp,
4288                             "please mail to linux-scsi@vger.kernel.org.\n");
4289                 return -ENODEV;
4290         }
4291
4292         scsi_autopm_get_device(SDp);
4293         i = queue_max_segments(SDp->request_queue);
4294         if (st_max_sg_segs < i)
4295                 i = st_max_sg_segs;
4296         buffer = new_tape_buffer(i);
4297         if (buffer == NULL) {
4298                 sdev_printk(KERN_ERR, SDp,
4299                             "st: Can't allocate new tape buffer. "
4300                             "Device not attached.\n");
4301                 goto out;
4302         }
4303
4304         disk = alloc_disk(1);
4305         if (!disk) {
4306                 sdev_printk(KERN_ERR, SDp,
4307                             "st: out of memory. Device not attached.\n");
4308                 goto out_buffer_free;
4309         }
4310
4311         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4312         if (tpnt == NULL) {
4313                 sdev_printk(KERN_ERR, SDp,
4314                             "st: Can't allocate device descriptor.\n");
4315                 goto out_put_disk;
4316         }
4317         kref_init(&tpnt->kref);
4318         tpnt->disk = disk;
4319         disk->private_data = &tpnt->driver;
4320         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4321          * take queue reference that release_disk() expects. */
4322         if (!blk_get_queue(SDp->request_queue))
4323                 goto out_put_disk;
4324         disk->queue = SDp->request_queue;
4325         tpnt->driver = &st_template;
4326
4327         tpnt->device = SDp;
4328         if (SDp->scsi_level <= 2)
4329                 tpnt->tape_type = MT_ISSCSI1;
4330         else
4331                 tpnt->tape_type = MT_ISSCSI2;
4332
4333         tpnt->buffer = buffer;
4334         tpnt->buffer->last_SRpnt = NULL;
4335
4336         tpnt->inited = 0;
4337         tpnt->dirty = 0;
4338         tpnt->in_use = 0;
4339         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4340         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4341         tpnt->density = 0;
4342         tpnt->do_auto_lock = ST_AUTO_LOCK;
4343         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4344         tpnt->can_partitions = 0;
4345         tpnt->two_fm = ST_TWO_FM;
4346         tpnt->fast_mteom = ST_FAST_MTEOM;
4347         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4348         tpnt->sili = ST_SILI;
4349         tpnt->immediate = ST_NOWAIT;
4350         tpnt->immediate_filemark = 0;
4351         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4352         tpnt->partition = 0;
4353         tpnt->new_partition = 0;
4354         tpnt->nbr_partitions = 0;
4355         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4356         tpnt->long_timeout = ST_LONG_TIMEOUT;
4357         tpnt->try_dio = try_direct_io;
4358
4359         for (i = 0; i < ST_NBR_MODES; i++) {
4360                 STm = &(tpnt->modes[i]);
4361                 STm->defined = 0;
4362                 STm->sysv = ST_SYSV;
4363                 STm->defaults_for_writes = 0;
4364                 STm->do_async_writes = ST_ASYNC_WRITES;
4365                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4366                 STm->do_read_ahead = ST_READ_AHEAD;
4367                 STm->default_compression = ST_DONT_TOUCH;
4368                 STm->default_blksize = (-1);    /* No forced size */
4369                 STm->default_density = (-1);    /* No forced density */
4370                 STm->tape = tpnt;
4371         }
4372
4373         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4374                 STps = &(tpnt->ps[i]);
4375                 STps->rw = ST_IDLE;
4376                 STps->eof = ST_NOEOF;
4377                 STps->at_sm = 0;
4378                 STps->last_block_valid = 0;
4379                 STps->drv_block = (-1);
4380                 STps->drv_file = (-1);
4381         }
4382
4383         tpnt->current_mode = 0;
4384         tpnt->modes[0].defined = 1;
4385
4386         tpnt->density_changed = tpnt->compression_changed =
4387             tpnt->blksize_changed = 0;
4388         mutex_init(&tpnt->lock);
4389
4390         idr_preload(GFP_KERNEL);
4391         spin_lock(&st_index_lock);
4392         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4393         spin_unlock(&st_index_lock);
4394         idr_preload_end();
4395         if (error < 0) {
4396                 pr_warn("st: idr allocation failed: %d\n", error);
4397                 goto out_put_queue;
4398         }
4399         tpnt->index = error;
4400         sprintf(disk->disk_name, "st%d", tpnt->index);
4401         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4402         if (tpnt->stats == NULL) {
4403                 sdev_printk(KERN_ERR, SDp,
4404                             "st: Can't allocate statistics.\n");
4405                 goto out_idr_remove;
4406         }
4407
4408         dev_set_drvdata(dev, tpnt);
4409
4410
4411         error = create_cdevs(tpnt);
4412         if (error)
4413                 goto out_remove_devs;
4414         scsi_autopm_put_device(SDp);
4415
4416         sdev_printk(KERN_NOTICE, SDp,
4417                     "Attached scsi tape %s\n", tape_name(tpnt));
4418         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4419                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4420                     queue_dma_alignment(SDp->request_queue) + 1);
4421
4422         return 0;
4423
4424 out_remove_devs:
4425         remove_cdevs(tpnt);
4426         kfree(tpnt->stats);
4427 out_idr_remove:
4428         spin_lock(&st_index_lock);
4429         idr_remove(&st_index_idr, tpnt->index);
4430         spin_unlock(&st_index_lock);
4431 out_put_queue:
4432         blk_put_queue(disk->queue);
4433 out_put_disk:
4434         put_disk(disk);
4435         kfree(tpnt);
4436 out_buffer_free:
4437         kfree(buffer);
4438 out:
4439         scsi_autopm_put_device(SDp);
4440         return -ENODEV;
4441 };
4442
4443
4444 static int st_remove(struct device *dev)
4445 {
4446         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4447         int index = tpnt->index;
4448
4449         scsi_autopm_get_device(to_scsi_device(dev));
4450         remove_cdevs(tpnt);
4451
4452         mutex_lock(&st_ref_mutex);
4453         kref_put(&tpnt->kref, scsi_tape_release);
4454         mutex_unlock(&st_ref_mutex);
4455         spin_lock(&st_index_lock);
4456         idr_remove(&st_index_idr, index);
4457         spin_unlock(&st_index_lock);
4458         return 0;
4459 }
4460
4461 /**
4462  *      scsi_tape_release - Called to free the Scsi_Tape structure
4463  *      @kref: pointer to embedded kref
4464  *
4465  *      st_ref_mutex must be held entering this routine.  Because it is
4466  *      called on last put, you should always use the scsi_tape_get()
4467  *      scsi_tape_put() helpers which manipulate the semaphore directly
4468  *      and never do a direct kref_put().
4469  **/
4470 static void scsi_tape_release(struct kref *kref)
4471 {
4472         struct scsi_tape *tpnt = to_scsi_tape(kref);
4473         struct gendisk *disk = tpnt->disk;
4474
4475         tpnt->device = NULL;
4476
4477         if (tpnt->buffer) {
4478                 normalize_buffer(tpnt->buffer);
4479                 kfree(tpnt->buffer->reserved_pages);
4480                 kfree(tpnt->buffer);
4481         }
4482
4483         disk->private_data = NULL;
4484         put_disk(disk);
4485         kfree(tpnt->stats);
4486         kfree(tpnt);
4487         return;
4488 }
4489
4490 static struct class st_sysfs_class = {
4491         .name = "scsi_tape",
4492         .dev_groups = st_dev_groups,
4493 };
4494
4495 static int __init init_st(void)
4496 {
4497         int err;
4498
4499         validate_options();
4500
4501         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4502                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4503
4504         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4505         if (debugging) {
4506                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4507                         debugging);
4508         }
4509
4510         err = class_register(&st_sysfs_class);
4511         if (err) {
4512                 pr_err("Unable register sysfs class for SCSI tapes\n");
4513                 return err;
4514         }
4515
4516         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4517                                      ST_MAX_TAPE_ENTRIES, "st");
4518         if (err) {
4519                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4520                        SCSI_TAPE_MAJOR);
4521                 goto err_class;
4522         }
4523
4524         err = scsi_register_driver(&st_template.gendrv);
4525         if (err)
4526                 goto err_chrdev;
4527
4528         return 0;
4529
4530 err_chrdev:
4531         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4532                                  ST_MAX_TAPE_ENTRIES);
4533 err_class:
4534         class_unregister(&st_sysfs_class);
4535         return err;
4536 }
4537
4538 static void __exit exit_st(void)
4539 {
4540         scsi_unregister_driver(&st_template.gendrv);
4541         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4542                                  ST_MAX_TAPE_ENTRIES);
4543         class_unregister(&st_sysfs_class);
4544         idr_destroy(&st_index_idr);
4545         printk(KERN_INFO "st: Unloaded.\n");
4546 }
4547
4548 module_init(init_st);
4549 module_exit(exit_st);
4550
4551
4552 /* The sysfs driver interface. Read-only at the moment */
4553 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4554 {
4555         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4556 }
4557 static DRIVER_ATTR_RO(try_direct_io);
4558
4559 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4560 {
4561         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4562 }
4563 static DRIVER_ATTR_RO(fixed_buffer_size);
4564
4565 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4566 {
4567         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4568 }
4569 static DRIVER_ATTR_RO(max_sg_segs);
4570
4571 static ssize_t version_show(struct device_driver *ddd, char *buf)
4572 {
4573         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4574 }
4575 static DRIVER_ATTR_RO(version);
4576
4577 #if DEBUG
4578 static ssize_t debug_flag_store(struct device_driver *ddp,
4579         const char *buf, size_t count)
4580 {
4581 /* We only care what the first byte of the data is the rest is unused.
4582  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4583  * other values have -EINVAL returned if they are passed in.
4584  */
4585         if (count > 0) {
4586                 if (buf[0] == '0') {
4587                         debugging = NO_DEBUG;
4588                         return count;
4589                 } else if (buf[0] == '1') {
4590                         debugging = 1;
4591                         return count;
4592                 }
4593         }
4594         return -EINVAL;
4595 }
4596
4597 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4598 {
4599         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4600 }
4601 static DRIVER_ATTR_RW(debug_flag);
4602 #endif
4603
4604 static struct attribute *st_drv_attrs[] = {
4605         &driver_attr_try_direct_io.attr,
4606         &driver_attr_fixed_buffer_size.attr,
4607         &driver_attr_max_sg_segs.attr,
4608         &driver_attr_version.attr,
4609 #if DEBUG
4610         &driver_attr_debug_flag.attr,
4611 #endif
4612         NULL,
4613 };
4614 ATTRIBUTE_GROUPS(st_drv);
4615
4616 /* The sysfs simple class interface */
4617 static ssize_t
4618 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4619 {
4620         struct st_modedef *STm = dev_get_drvdata(dev);
4621         ssize_t l = 0;
4622
4623         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4624         return l;
4625 }
4626 static DEVICE_ATTR_RO(defined);
4627
4628 static ssize_t
4629 default_blksize_show(struct device *dev, struct device_attribute *attr,
4630                      char *buf)
4631 {
4632         struct st_modedef *STm = dev_get_drvdata(dev);
4633         ssize_t l = 0;
4634
4635         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4636         return l;
4637 }
4638 static DEVICE_ATTR_RO(default_blksize);
4639
4640 static ssize_t
4641 default_density_show(struct device *dev, struct device_attribute *attr,
4642                      char *buf)
4643 {
4644         struct st_modedef *STm = dev_get_drvdata(dev);
4645         ssize_t l = 0;
4646         char *fmt;
4647
4648         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4649         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4650         return l;
4651 }
4652 static DEVICE_ATTR_RO(default_density);
4653
4654 static ssize_t
4655 default_compression_show(struct device *dev, struct device_attribute *attr,
4656                          char *buf)
4657 {
4658         struct st_modedef *STm = dev_get_drvdata(dev);
4659         ssize_t l = 0;
4660
4661         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4662         return l;
4663 }
4664 static DEVICE_ATTR_RO(default_compression);
4665
4666 static ssize_t
4667 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4668 {
4669         struct st_modedef *STm = dev_get_drvdata(dev);
4670         struct scsi_tape *STp = STm->tape;
4671         int options;
4672         ssize_t l = 0;
4673
4674         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4675         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4676         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4677         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4678         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4679         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4680         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4681         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4682         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4683         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4684         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4685         options |= STm->sysv ? MT_ST_SYSV : 0;
4686         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4687         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4688         options |= STp->sili ? MT_ST_SILI : 0;
4689
4690         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4691         return l;
4692 }
4693 static DEVICE_ATTR_RO(options);
4694
4695 /* Support for tape stats */
4696
4697 /**
4698  * read_cnt_show - return read count - count of reads made from tape drive
4699  * @dev: struct device
4700  * @attr: attribute structure
4701  * @buf: buffer to return formatted data in
4702  */
4703 static ssize_t read_cnt_show(struct device *dev,
4704         struct device_attribute *attr, char *buf)
4705 {
4706         struct st_modedef *STm = dev_get_drvdata(dev);
4707
4708         return sprintf(buf, "%lld",
4709                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4710 }
4711 static DEVICE_ATTR_RO(read_cnt);
4712
4713 /**
4714  * read_byte_cnt_show - return read byte count - tape drives
4715  * may use blocks less than 512 bytes this gives the raw byte count of
4716  * of data read from the tape drive.
4717  * @dev: struct device
4718  * @attr: attribute structure
4719  * @buf: buffer to return formatted data in
4720  */
4721 static ssize_t read_byte_cnt_show(struct device *dev,
4722         struct device_attribute *attr, char *buf)
4723 {
4724         struct st_modedef *STm = dev_get_drvdata(dev);
4725
4726         return sprintf(buf, "%lld",
4727                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4728 }
4729 static DEVICE_ATTR_RO(read_byte_cnt);
4730
4731 /**
4732  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4733  * @dev: struct device
4734  * @attr: attribute structure
4735  * @buf: buffer to return formatted data in
4736  */
4737 static ssize_t read_ns_show(struct device *dev,
4738         struct device_attribute *attr, char *buf)
4739 {
4740         struct st_modedef *STm = dev_get_drvdata(dev);
4741
4742         return sprintf(buf, "%lld",
4743                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4744 }
4745 static DEVICE_ATTR_RO(read_ns);
4746
4747 /**
4748  * write_cnt_show - write count - number of user calls
4749  * to write(2) that have written data to tape.
4750  * @dev: struct device
4751  * @attr: attribute structure
4752  * @buf: buffer to return formatted data in
4753  */
4754 static ssize_t write_cnt_show(struct device *dev,
4755         struct device_attribute *attr, char *buf)
4756 {
4757         struct st_modedef *STm = dev_get_drvdata(dev);
4758
4759         return sprintf(buf, "%lld",
4760                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4761 }
4762 static DEVICE_ATTR_RO(write_cnt);
4763
4764 /**
4765  * write_byte_cnt_show - write byte count - raw count of
4766  * bytes written to tape.
4767  * @dev: struct device
4768  * @attr: attribute structure
4769  * @buf: buffer to return formatted data in
4770  */
4771 static ssize_t write_byte_cnt_show(struct device *dev,
4772         struct device_attribute *attr, char *buf)
4773 {
4774         struct st_modedef *STm = dev_get_drvdata(dev);
4775
4776         return sprintf(buf, "%lld",
4777                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4778 }
4779 static DEVICE_ATTR_RO(write_byte_cnt);
4780
4781 /**
4782  * write_ns_show - write ns - number of nanoseconds waiting on write
4783  * requests to complete.
4784  * @dev: struct device
4785  * @attr: attribute structure
4786  * @buf: buffer to return formatted data in
4787  */
4788 static ssize_t write_ns_show(struct device *dev,
4789         struct device_attribute *attr, char *buf)
4790 {
4791         struct st_modedef *STm = dev_get_drvdata(dev);
4792
4793         return sprintf(buf, "%lld",
4794                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4795 }
4796 static DEVICE_ATTR_RO(write_ns);
4797
4798 /**
4799  * in_flight_show - number of I/Os currently in flight -
4800  * in most cases this will be either 0 or 1. It may be higher if someone
4801  * has also issued other SCSI commands such as via an ioctl.
4802  * @dev: struct device
4803  * @attr: attribute structure
4804  * @buf: buffer to return formatted data in
4805  */
4806 static ssize_t in_flight_show(struct device *dev,
4807         struct device_attribute *attr, char *buf)
4808 {
4809         struct st_modedef *STm = dev_get_drvdata(dev);
4810
4811         return sprintf(buf, "%lld",
4812                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4813 }
4814 static DEVICE_ATTR_RO(in_flight);
4815
4816 /**
4817  * io_ns_show - io wait ns - this is the number of ns spent
4818  * waiting on all I/O to complete. This includes tape movement commands
4819  * such as rewinding, seeking to end of file or tape, it also includes
4820  * read and write. To determine the time spent on tape movement
4821  * subtract the read and write ns from this value.
4822  * @dev: struct device
4823  * @attr: attribute structure
4824  * @buf: buffer to return formatted data in
4825  */
4826 static ssize_t io_ns_show(struct device *dev,
4827         struct device_attribute *attr, char *buf)
4828 {
4829         struct st_modedef *STm = dev_get_drvdata(dev);
4830
4831         return sprintf(buf, "%lld",
4832                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4833 }
4834 static DEVICE_ATTR_RO(io_ns);
4835
4836 /**
4837  * other_cnt_show - other io count - this is the number of
4838  * I/O requests other than read and write requests.
4839  * Typically these are tape movement requests but will include driver
4840  * tape movement. This includes only requests issued by the st driver.
4841  * @dev: struct device
4842  * @attr: attribute structure
4843  * @buf: buffer to return formatted data in
4844  */
4845 static ssize_t other_cnt_show(struct device *dev,
4846         struct device_attribute *attr, char *buf)
4847 {
4848         struct st_modedef *STm = dev_get_drvdata(dev);
4849
4850         return sprintf(buf, "%lld",
4851                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4852 }
4853 static DEVICE_ATTR_RO(other_cnt);
4854
4855 /**
4856  * resid_cnt_show - A count of the number of times we get a residual
4857  * count - this should indicate someone issuing reads larger than the
4858  * block size on tape.
4859  * @dev: struct device
4860  * @attr: attribute structure
4861  * @buf: buffer to return formatted data in
4862  */
4863 static ssize_t resid_cnt_show(struct device *dev,
4864         struct device_attribute *attr, char *buf)
4865 {
4866         struct st_modedef *STm = dev_get_drvdata(dev);
4867
4868         return sprintf(buf, "%lld",
4869                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4870 }
4871 static DEVICE_ATTR_RO(resid_cnt);
4872
4873 static struct attribute *st_dev_attrs[] = {
4874         &dev_attr_defined.attr,
4875         &dev_attr_default_blksize.attr,
4876         &dev_attr_default_density.attr,
4877         &dev_attr_default_compression.attr,
4878         &dev_attr_options.attr,
4879         NULL,
4880 };
4881
4882 static struct attribute *st_stats_attrs[] = {
4883         &dev_attr_read_cnt.attr,
4884         &dev_attr_read_byte_cnt.attr,
4885         &dev_attr_read_ns.attr,
4886         &dev_attr_write_cnt.attr,
4887         &dev_attr_write_byte_cnt.attr,
4888         &dev_attr_write_ns.attr,
4889         &dev_attr_in_flight.attr,
4890         &dev_attr_io_ns.attr,
4891         &dev_attr_other_cnt.attr,
4892         &dev_attr_resid_cnt.attr,
4893         NULL,
4894 };
4895
4896 static struct attribute_group stats_group = {
4897         .name = "stats",
4898         .attrs = st_stats_attrs,
4899 };
4900
4901 static struct attribute_group st_group = {
4902         .attrs = st_dev_attrs,
4903 };
4904
4905 static const struct attribute_group *st_dev_groups[] = {
4906         &st_group,
4907         &stats_group,
4908         NULL,
4909 };
4910
4911 /* The following functions may be useful for a larger audience. */
4912 static int sgl_map_user_pages(struct st_buffer *STbp,
4913                               const unsigned int max_pages, unsigned long uaddr,
4914                               size_t count, int rw)
4915 {
4916         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4917         unsigned long start = uaddr >> PAGE_SHIFT;
4918         const int nr_pages = end - start;
4919         int res, i;
4920         struct page **pages;
4921         struct rq_map_data *mdata = &STbp->map_data;
4922
4923         /* User attempted Overflow! */
4924         if ((uaddr + count) < uaddr)
4925                 return -EINVAL;
4926
4927         /* Too big */
4928         if (nr_pages > max_pages)
4929                 return -ENOMEM;
4930
4931         /* Hmm? */
4932         if (count == 0)
4933                 return 0;
4934
4935         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4936         if (pages == NULL)
4937                 return -ENOMEM;
4938
4939         /* Try to fault in all of the necessary pages */
4940         /* rw==READ means read from drive, write into memory area */
4941         res = pin_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4942                                   pages);
4943
4944         /* Errors and no page mapped should return here */
4945         if (res < nr_pages)
4946                 goto out_unmap;
4947
4948         for (i=0; i < nr_pages; i++) {
4949                 /* FIXME: flush superflous for rw==READ,
4950                  * probably wrong function for rw==WRITE
4951                  */
4952                 flush_dcache_page(pages[i]);
4953         }
4954
4955         mdata->offset = uaddr & ~PAGE_MASK;
4956         STbp->mapped_pages = pages;
4957
4958         return nr_pages;
4959  out_unmap:
4960         if (res > 0) {
4961                 unpin_user_pages(pages, res);
4962                 res = 0;
4963         }
4964         kfree(pages);
4965         return res;
4966 }
4967
4968
4969 /* And unmap them... */
4970 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4971                                 const unsigned int nr_pages, int dirtied)
4972 {
4973         /* FIXME: cache flush missing for rw==READ */
4974         unpin_user_pages_dirty_lock(STbp->mapped_pages, nr_pages, dirtied);
4975
4976         kfree(STbp->mapped_pages);
4977         STbp->mapped_pages = NULL;
4978
4979         return 0;
4980 }