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(struct file *file, unsigned int cmd_in, unsigned long arg)
3503 {
3504         void __user *p = (void __user *)arg;
3505         int i, cmd_nr, cmd_type, bt;
3506         int retval = 0;
3507         unsigned int blk;
3508         struct scsi_tape *STp = file->private_data;
3509         struct st_modedef *STm;
3510         struct st_partstat *STps;
3511
3512         if (mutex_lock_interruptible(&STp->lock))
3513                 return -ERESTARTSYS;
3514
3515         DEB(
3516         if (debugging && !STp->in_use) {
3517                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3518                 retval = (-EIO);
3519                 goto out;
3520         } ) /* end DEB */
3521
3522         STm = &(STp->modes[STp->current_mode]);
3523         STps = &(STp->ps[STp->partition]);
3524
3525         /*
3526          * If we are in the middle of error recovery, don't let anyone
3527          * else try and use this device.  Also, if error recovery fails, it
3528          * may try and take the device offline, in which case all further
3529          * access to the device is prohibited.
3530          */
3531         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3532                         file->f_flags & O_NDELAY);
3533         if (retval)
3534                 goto out;
3535
3536         cmd_type = _IOC_TYPE(cmd_in);
3537         cmd_nr = _IOC_NR(cmd_in);
3538
3539         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3540                 struct mtop mtc;
3541
3542                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3543                         retval = (-EINVAL);
3544                         goto out;
3545                 }
3546
3547                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3548                 if (i) {
3549                         retval = (-EFAULT);
3550                         goto out;
3551                 }
3552
3553                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3554                         st_printk(KERN_WARNING, STp,
3555                                   "MTSETDRVBUFFER only allowed for root.\n");
3556                         retval = (-EPERM);
3557                         goto out;
3558                 }
3559                 if (!STm->defined &&
3560                     (mtc.mt_op != MTSETDRVBUFFER &&
3561                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3562                         retval = (-ENXIO);
3563                         goto out;
3564                 }
3565
3566                 if (!STp->pos_unknown) {
3567
3568                         if (STps->eof == ST_FM_HIT) {
3569                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3570                                     mtc.mt_op == MTEOM) {
3571                                         mtc.mt_count -= 1;
3572                                         if (STps->drv_file >= 0)
3573                                                 STps->drv_file += 1;
3574                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3575                                         mtc.mt_count += 1;
3576                                         if (STps->drv_file >= 0)
3577                                                 STps->drv_file += 1;
3578                                 }
3579                         }
3580
3581                         if (mtc.mt_op == MTSEEK) {
3582                                 /* Old position must be restored if partition will be
3583                                    changed */
3584                                 i = !STp->can_partitions ||
3585                                     (STp->new_partition != STp->partition);
3586                         } else {
3587                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3588                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3589                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3590                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3591                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3592                                     mtc.mt_op == MTCOMPRESSION;
3593                         }
3594                         i = flush_buffer(STp, i);
3595                         if (i < 0) {
3596                                 retval = i;
3597                                 goto out;
3598                         }
3599                         if (STps->rw == ST_WRITING &&
3600                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3601                              mtc.mt_op == MTSEEK ||
3602                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3603                                 i = st_int_ioctl(STp, MTWEOF, 1);
3604                                 if (i < 0) {
3605                                         retval = i;
3606                                         goto out;
3607                                 }
3608                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3609                                         mtc.mt_count++;
3610                                 STps->rw = ST_IDLE;
3611                              }
3612
3613                 } else {
3614                         /*
3615                          * If there was a bus reset, block further access
3616                          * to this device.  If the user wants to rewind the tape,
3617                          * then reset the flag and allow access again.
3618                          */
3619                         if (mtc.mt_op != MTREW &&
3620                             mtc.mt_op != MTOFFL &&
3621                             mtc.mt_op != MTRETEN &&
3622                             mtc.mt_op != MTERASE &&
3623                             mtc.mt_op != MTSEEK &&
3624                             mtc.mt_op != MTEOM) {
3625                                 retval = (-EIO);
3626                                 goto out;
3627                         }
3628                         reset_state(STp);
3629                         /* remove this when the midlevel properly clears was_reset */
3630                         STp->device->was_reset = 0;
3631                 }
3632
3633                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3634                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3635                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3636                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3637
3638                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3639                         do_door_lock(STp, 0);   /* Ignore result! */
3640
3641                 if (mtc.mt_op == MTSETDRVBUFFER &&
3642                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3643                         retval = st_set_options(STp, mtc.mt_count);
3644                         goto out;
3645                 }
3646
3647                 if (mtc.mt_op == MTSETPART) {
3648                         if (!STp->can_partitions ||
3649                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3650                                 retval = (-EINVAL);
3651                                 goto out;
3652                         }
3653                         if (mtc.mt_count >= STp->nbr_partitions &&
3654                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3655                                 retval = (-EIO);
3656                                 goto out;
3657                         }
3658                         if (mtc.mt_count >= STp->nbr_partitions) {
3659                                 retval = (-EINVAL);
3660                                 goto out;
3661                         }
3662                         STp->new_partition = mtc.mt_count;
3663                         retval = 0;
3664                         goto out;
3665                 }
3666
3667                 if (mtc.mt_op == MTMKPART) {
3668                         if (!STp->can_partitions) {
3669                                 retval = (-EINVAL);
3670                                 goto out;
3671                         }
3672                         i = do_load_unload(STp, file, 1);
3673                         if (i < 0) {
3674                                 retval = i;
3675                                 goto out;
3676                         }
3677                         i = partition_tape(STp, mtc.mt_count);
3678                         if (i < 0) {
3679                                 retval = i;
3680                                 goto out;
3681                         }
3682                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3683                                 STp->ps[i].rw = ST_IDLE;
3684                                 STp->ps[i].at_sm = 0;
3685                                 STp->ps[i].last_block_valid = 0;
3686                         }
3687                         STp->partition = STp->new_partition = 0;
3688                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3689                         STps->drv_block = STps->drv_file = 0;
3690                         retval = 0;
3691                         goto out;
3692                 }
3693
3694                 if (mtc.mt_op == MTSEEK) {
3695                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3696                         if (!STp->can_partitions)
3697                                 STp->ps[0].rw = ST_IDLE;
3698                         retval = i;
3699                         goto out;
3700                 }
3701
3702                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3703                         retval = do_load_unload(STp, file, 0);
3704                         goto out;
3705                 }
3706
3707                 if (mtc.mt_op == MTLOAD) {
3708                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3709                         goto out;
3710                 }
3711
3712                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3713                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3714                         goto out;
3715                 }
3716
3717                 if (STp->can_partitions && STp->ready == ST_READY &&
3718                     (i = switch_partition(STp)) < 0) {
3719                         retval = i;
3720                         goto out;
3721                 }
3722
3723                 if (mtc.mt_op == MTCOMPRESSION)
3724                         retval = st_compression(STp, (mtc.mt_count & 1));
3725                 else
3726                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3727                 goto out;
3728         }
3729         if (!STm->defined) {
3730                 retval = (-ENXIO);
3731                 goto out;
3732         }
3733
3734         if ((i = flush_buffer(STp, 0)) < 0) {
3735                 retval = i;
3736                 goto out;
3737         }
3738         if (STp->can_partitions &&
3739             (i = switch_partition(STp)) < 0) {
3740                 retval = i;
3741                 goto out;
3742         }
3743
3744         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3745                 struct mtget mt_status;
3746
3747                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3748                          retval = (-EINVAL);
3749                          goto out;
3750                 }
3751
3752                 mt_status.mt_type = STp->tape_type;
3753                 mt_status.mt_dsreg =
3754                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3755                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3756                 mt_status.mt_blkno = STps->drv_block;
3757                 mt_status.mt_fileno = STps->drv_file;
3758                 if (STp->block_size != 0) {
3759                         if (STps->rw == ST_WRITING)
3760                                 mt_status.mt_blkno +=
3761                                     (STp->buffer)->buffer_bytes / STp->block_size;
3762                         else if (STps->rw == ST_READING)
3763                                 mt_status.mt_blkno -=
3764                                         ((STp->buffer)->buffer_bytes +
3765                                          STp->block_size - 1) / STp->block_size;
3766                 }
3767
3768                 mt_status.mt_gstat = 0;
3769                 if (STp->drv_write_prot)
3770                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3771                 if (mt_status.mt_blkno == 0) {
3772                         if (mt_status.mt_fileno == 0)
3773                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3774                         else
3775                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3776                 }
3777                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3778                 mt_status.mt_resid = STp->partition;
3779                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3780                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3781                 else if (STps->eof >= ST_EOM_OK)
3782                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3783                 if (STp->density == 1)
3784                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3785                 else if (STp->density == 2)
3786                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3787                 else if (STp->density == 3)
3788                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3789                 if (STp->ready == ST_READY)
3790                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3791                 if (STp->ready == ST_NO_TAPE)
3792                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3793                 if (STps->at_sm)
3794                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3795                 if (STm->do_async_writes ||
3796                     (STm->do_buffer_writes && STp->block_size != 0) ||
3797                     STp->drv_buffer != 0)
3798                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3799                 if (STp->cleaning_req)
3800                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3801
3802                 retval = put_user_mtget(p, &mt_status);
3803                 if (retval)
3804                         goto out;
3805
3806                 STp->recover_reg = 0;           /* Clear after read */
3807                 goto out;
3808         }                       /* End of MTIOCGET */
3809         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3810                 struct mtpos mt_pos;
3811                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3812                          retval = (-EINVAL);
3813                          goto out;
3814                 }
3815                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3816                         retval = i;
3817                         goto out;
3818                 }
3819                 mt_pos.mt_blkno = blk;
3820                 retval = put_user_mtpos(p, &mt_pos);
3821                 goto out;
3822         }
3823         mutex_unlock(&STp->lock);
3824
3825         switch (cmd_in) {
3826         case SG_IO:
3827         case SCSI_IOCTL_SEND_COMMAND:
3828         case CDROM_SEND_PACKET:
3829                 if (!capable(CAP_SYS_RAWIO))
3830                         return -EPERM;
3831         default:
3832                 break;
3833         }
3834
3835         retval = scsi_ioctl(STp->device, STp->disk, file->f_mode, cmd_in, p);
3836         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) {
3837                 /* unload */
3838                 STp->rew_at_close = 0;
3839                 STp->ready = ST_NO_TAPE;
3840         }
3841         return retval;
3842
3843  out:
3844         mutex_unlock(&STp->lock);
3845         return retval;
3846 }
3847
3848 #ifdef CONFIG_COMPAT
3849 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3850 {
3851         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3852         switch (cmd_in) {
3853         case MTIOCPOS32:
3854                 cmd_in = MTIOCPOS;
3855                 break;
3856         case MTIOCGET32:
3857                 cmd_in = MTIOCGET;
3858                 break;
3859         }
3860
3861         return st_ioctl(file, cmd_in, arg);
3862 }
3863 #endif
3864
3865 \f
3866
3867 /* Try to allocate a new tape buffer. Calling function must not hold
3868    dev_arr_lock. */
3869 static struct st_buffer *new_tape_buffer(int max_sg)
3870 {
3871         struct st_buffer *tb;
3872
3873         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3874         if (!tb) {
3875                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3876                 return NULL;
3877         }
3878         tb->frp_segs = 0;
3879         tb->use_sg = max_sg;
3880         tb->buffer_size = 0;
3881
3882         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3883                                      GFP_KERNEL);
3884         if (!tb->reserved_pages) {
3885                 kfree(tb);
3886                 return NULL;
3887         }
3888
3889         return tb;
3890 }
3891
3892
3893 /* Try to allocate enough space in the tape buffer */
3894 #define ST_MAX_ORDER 6
3895
3896 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size)
3897 {
3898         int segs, max_segs, b_size, order, got;
3899         gfp_t priority;
3900
3901         if (new_size <= STbuffer->buffer_size)
3902                 return 1;
3903
3904         if (STbuffer->buffer_size <= PAGE_SIZE)
3905                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3906
3907         max_segs = STbuffer->use_sg;
3908
3909         priority = GFP_KERNEL | __GFP_NOWARN;
3910
3911         if (STbuffer->cleared)
3912                 priority |= __GFP_ZERO;
3913
3914         if (STbuffer->frp_segs) {
3915                 order = STbuffer->reserved_page_order;
3916                 b_size = PAGE_SIZE << order;
3917         } else {
3918                 for (b_size = PAGE_SIZE, order = 0;
3919                      order < ST_MAX_ORDER &&
3920                              max_segs * (PAGE_SIZE << order) < new_size;
3921                      order++, b_size *= 2)
3922                         ;  /* empty */
3923                 STbuffer->reserved_page_order = order;
3924         }
3925         if (max_segs * (PAGE_SIZE << order) < new_size) {
3926                 if (order == ST_MAX_ORDER)
3927                         return 0;
3928                 normalize_buffer(STbuffer);
3929                 return enlarge_buffer(STbuffer, new_size);
3930         }
3931
3932         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3933              segs < max_segs && got < new_size;) {
3934                 struct page *page;
3935
3936                 page = alloc_pages(priority, order);
3937                 if (!page) {
3938                         DEB(STbuffer->buffer_size = got);
3939                         normalize_buffer(STbuffer);
3940                         return 0;
3941                 }
3942
3943                 STbuffer->frp_segs += 1;
3944                 got += b_size;
3945                 STbuffer->buffer_size = got;
3946                 STbuffer->reserved_pages[segs] = page;
3947                 segs++;
3948         }
3949         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3950
3951         return 1;
3952 }
3953
3954
3955 /* Make sure that no data from previous user is in the internal buffer */
3956 static void clear_buffer(struct st_buffer * st_bp)
3957 {
3958         int i;
3959
3960         for (i=0; i < st_bp->frp_segs; i++)
3961                 memset(page_address(st_bp->reserved_pages[i]), 0,
3962                        PAGE_SIZE << st_bp->reserved_page_order);
3963         st_bp->cleared = 1;
3964 }
3965
3966
3967 /* Release the extra buffer */
3968 static void normalize_buffer(struct st_buffer * STbuffer)
3969 {
3970         int i, order = STbuffer->reserved_page_order;
3971
3972         for (i = 0; i < STbuffer->frp_segs; i++) {
3973                 __free_pages(STbuffer->reserved_pages[i], order);
3974                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3975         }
3976         STbuffer->frp_segs = 0;
3977         STbuffer->sg_segs = 0;
3978         STbuffer->reserved_page_order = 0;
3979         STbuffer->map_data.offset = 0;
3980 }
3981
3982
3983 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3984    negative error code. */
3985 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3986 {
3987         int i, cnt, res, offset;
3988         int length = PAGE_SIZE << st_bp->reserved_page_order;
3989
3990         for (i = 0, offset = st_bp->buffer_bytes;
3991              i < st_bp->frp_segs && offset >= length; i++)
3992                 offset -= length;
3993         if (i == st_bp->frp_segs) {     /* Should never happen */
3994                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3995                 return (-EIO);
3996         }
3997         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3998                 struct page *page = st_bp->reserved_pages[i];
3999                 cnt = length - offset < do_count ? length - offset : do_count;
4000                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4001                 if (res)
4002                         return (-EFAULT);
4003                 do_count -= cnt;
4004                 st_bp->buffer_bytes += cnt;
4005                 ubp += cnt;
4006                 offset = 0;
4007         }
4008         if (do_count) /* Should never happen */
4009                 return (-EIO);
4010
4011         return 0;
4012 }
4013
4014
4015 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4016    negative error code. */
4017 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4018 {
4019         int i, cnt, res, offset;
4020         int length = PAGE_SIZE << st_bp->reserved_page_order;
4021
4022         for (i = 0, offset = st_bp->read_pointer;
4023              i < st_bp->frp_segs && offset >= length; i++)
4024                 offset -= length;
4025         if (i == st_bp->frp_segs) {     /* Should never happen */
4026                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4027                 return (-EIO);
4028         }
4029         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4030                 struct page *page = st_bp->reserved_pages[i];
4031                 cnt = length - offset < do_count ? length - offset : do_count;
4032                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4033                 if (res)
4034                         return (-EFAULT);
4035                 do_count -= cnt;
4036                 st_bp->buffer_bytes -= cnt;
4037                 st_bp->read_pointer += cnt;
4038                 ubp += cnt;
4039                 offset = 0;
4040         }
4041         if (do_count) /* Should never happen */
4042                 return (-EIO);
4043
4044         return 0;
4045 }
4046
4047
4048 /* Move data towards start of buffer */
4049 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4050 {
4051         int src_seg, dst_seg, src_offset = 0, dst_offset;
4052         int count, total;
4053         int length = PAGE_SIZE << st_bp->reserved_page_order;
4054
4055         if (offset == 0)
4056                 return;
4057
4058         total=st_bp->buffer_bytes - offset;
4059         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4060                 src_offset = offset;
4061                 if (src_offset < length)
4062                         break;
4063                 offset -= length;
4064         }
4065
4066         st_bp->buffer_bytes = st_bp->read_pointer = total;
4067         for (dst_seg=dst_offset=0; total > 0; ) {
4068                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4069                 struct page *spage = st_bp->reserved_pages[src_seg];
4070
4071                 count = min(length - dst_offset, length - src_offset);
4072                 memmove(page_address(dpage) + dst_offset,
4073                         page_address(spage) + src_offset, count);
4074                 src_offset += count;
4075                 if (src_offset >= length) {
4076                         src_seg++;
4077                         src_offset = 0;
4078                 }
4079                 dst_offset += count;
4080                 if (dst_offset >= length) {
4081                         dst_seg++;
4082                         dst_offset = 0;
4083                 }
4084                 total -= count;
4085         }
4086 }
4087
4088 /* Validate the options from command line or module parameters */
4089 static void validate_options(void)
4090 {
4091         if (buffer_kbs > 0)
4092                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4093         if (max_sg_segs >= ST_FIRST_SG)
4094                 st_max_sg_segs = max_sg_segs;
4095 }
4096
4097 #ifndef MODULE
4098 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4099  */
4100 static int __init st_setup(char *str)
4101 {
4102         int i, len, ints[5];
4103         char *stp;
4104
4105         stp = get_options(str, ARRAY_SIZE(ints), ints);
4106
4107         if (ints[0] > 0) {
4108                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4109                         if (parms[i].val)
4110                                 *parms[i].val = ints[i + 1];
4111         } else {
4112                 while (stp != NULL) {
4113                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4114                                 len = strlen(parms[i].name);
4115                                 if (!strncmp(stp, parms[i].name, len) &&
4116                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4117                                         if (parms[i].val)
4118                                                 *parms[i].val =
4119                                                         simple_strtoul(stp + len + 1, NULL, 0);
4120                                         else
4121                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4122                                                        parms[i].name);
4123                                         break;
4124                                 }
4125                         }
4126                         if (i >= ARRAY_SIZE(parms))
4127                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4128                                         stp);
4129                         stp = strchr(stp, ',');
4130                         if (stp)
4131                                 stp++;
4132                 }
4133         }
4134
4135         validate_options();
4136
4137         return 1;
4138 }
4139
4140 __setup("st=", st_setup);
4141
4142 #endif
4143
4144 static const struct file_operations st_fops =
4145 {
4146         .owner =        THIS_MODULE,
4147         .read =         st_read,
4148         .write =        st_write,
4149         .unlocked_ioctl = st_ioctl,
4150 #ifdef CONFIG_COMPAT
4151         .compat_ioctl = st_compat_ioctl,
4152 #endif
4153         .open =         st_open,
4154         .flush =        st_flush,
4155         .release =      st_release,
4156         .llseek =       noop_llseek,
4157 };
4158
4159 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4160 {
4161         int i, error;
4162         dev_t cdev_devno;
4163         struct cdev *cdev;
4164         struct device *dev;
4165         struct st_modedef *STm = &(tape->modes[mode]);
4166         char name[10];
4167         int dev_num = tape->index;
4168
4169         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4170
4171         cdev = cdev_alloc();
4172         if (!cdev) {
4173                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4174                 error = -ENOMEM;
4175                 goto out;
4176         }
4177         cdev->owner = THIS_MODULE;
4178         cdev->ops = &st_fops;
4179         STm->cdevs[rew] = cdev;
4180
4181         error = cdev_add(cdev, cdev_devno, 1);
4182         if (error) {
4183                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4184                        rew ? "non" : "auto", mode);
4185                 pr_err("st%d: Device not attached.\n", dev_num);
4186                 goto out_free;
4187         }
4188
4189         i = mode << (4 - ST_NBR_MODE_BITS);
4190         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4191                  tape->disk->disk_name, st_formats[i]);
4192
4193         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4194                             cdev_devno, &tape->modes[mode], "%s", name);
4195         if (IS_ERR(dev)) {
4196                 pr_err("st%d: device_create failed\n", dev_num);
4197                 error = PTR_ERR(dev);
4198                 goto out_free;
4199         }
4200
4201         STm->devs[rew] = dev;
4202
4203         return 0;
4204 out_free:
4205         cdev_del(STm->cdevs[rew]);
4206 out:
4207         STm->cdevs[rew] = NULL;
4208         STm->devs[rew] = NULL;
4209         return error;
4210 }
4211
4212 static int create_cdevs(struct scsi_tape *tape)
4213 {
4214         int mode, error;
4215         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4216                 error = create_one_cdev(tape, mode, 0);
4217                 if (error)
4218                         return error;
4219                 error = create_one_cdev(tape, mode, 1);
4220                 if (error)
4221                         return error;
4222         }
4223
4224         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4225                                  &tape->modes[0].devs[0]->kobj, "tape");
4226 }
4227
4228 static void remove_cdevs(struct scsi_tape *tape)
4229 {
4230         int mode, rew;
4231         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4232         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4233                 struct st_modedef *STm = &(tape->modes[mode]);
4234                 for (rew = 0; rew < 2; rew++) {
4235                         if (STm->cdevs[rew])
4236                                 cdev_del(STm->cdevs[rew]);
4237                         if (STm->devs[rew])
4238                                 device_unregister(STm->devs[rew]);
4239                 }
4240         }
4241 }
4242
4243 static int st_probe(struct device *dev)
4244 {
4245         struct scsi_device *SDp = to_scsi_device(dev);
4246         struct gendisk *disk = NULL;
4247         struct scsi_tape *tpnt = NULL;
4248         struct st_modedef *STm;
4249         struct st_partstat *STps;
4250         struct st_buffer *buffer;
4251         int i, error;
4252         char *stp;
4253
4254         if (SDp->type != TYPE_TAPE)
4255                 return -ENODEV;
4256         if ((stp = st_incompatible(SDp))) {
4257                 sdev_printk(KERN_INFO, SDp,
4258                             "OnStream tapes are no longer supported;\n");
4259                 sdev_printk(KERN_INFO, SDp,
4260                             "please mail to linux-scsi@vger.kernel.org.\n");
4261                 return -ENODEV;
4262         }
4263
4264         scsi_autopm_get_device(SDp);
4265         i = queue_max_segments(SDp->request_queue);
4266         if (st_max_sg_segs < i)
4267                 i = st_max_sg_segs;
4268         buffer = new_tape_buffer(i);
4269         if (buffer == NULL) {
4270                 sdev_printk(KERN_ERR, SDp,
4271                             "st: Can't allocate new tape buffer. "
4272                             "Device not attached.\n");
4273                 goto out;
4274         }
4275
4276         disk = alloc_disk(1);
4277         if (!disk) {
4278                 sdev_printk(KERN_ERR, SDp,
4279                             "st: out of memory. Device not attached.\n");
4280                 goto out_buffer_free;
4281         }
4282
4283         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4284         if (tpnt == NULL) {
4285                 sdev_printk(KERN_ERR, SDp,
4286                             "st: Can't allocate device descriptor.\n");
4287                 goto out_put_disk;
4288         }
4289         kref_init(&tpnt->kref);
4290         tpnt->disk = disk;
4291         disk->private_data = &tpnt->driver;
4292         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4293          * take queue reference that release_disk() expects. */
4294         if (!blk_get_queue(SDp->request_queue))
4295                 goto out_put_disk;
4296         disk->queue = SDp->request_queue;
4297         tpnt->driver = &st_template;
4298
4299         tpnt->device = SDp;
4300         if (SDp->scsi_level <= 2)
4301                 tpnt->tape_type = MT_ISSCSI1;
4302         else
4303                 tpnt->tape_type = MT_ISSCSI2;
4304
4305         tpnt->buffer = buffer;
4306         tpnt->buffer->last_SRpnt = NULL;
4307
4308         tpnt->inited = 0;
4309         tpnt->dirty = 0;
4310         tpnt->in_use = 0;
4311         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4312         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4313         tpnt->density = 0;
4314         tpnt->do_auto_lock = ST_AUTO_LOCK;
4315         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4316         tpnt->can_partitions = 0;
4317         tpnt->two_fm = ST_TWO_FM;
4318         tpnt->fast_mteom = ST_FAST_MTEOM;
4319         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4320         tpnt->sili = ST_SILI;
4321         tpnt->immediate = ST_NOWAIT;
4322         tpnt->immediate_filemark = 0;
4323         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4324         tpnt->partition = 0;
4325         tpnt->new_partition = 0;
4326         tpnt->nbr_partitions = 0;
4327         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4328         tpnt->long_timeout = ST_LONG_TIMEOUT;
4329         tpnt->try_dio = try_direct_io;
4330
4331         for (i = 0; i < ST_NBR_MODES; i++) {
4332                 STm = &(tpnt->modes[i]);
4333                 STm->defined = 0;
4334                 STm->sysv = ST_SYSV;
4335                 STm->defaults_for_writes = 0;
4336                 STm->do_async_writes = ST_ASYNC_WRITES;
4337                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4338                 STm->do_read_ahead = ST_READ_AHEAD;
4339                 STm->default_compression = ST_DONT_TOUCH;
4340                 STm->default_blksize = (-1);    /* No forced size */
4341                 STm->default_density = (-1);    /* No forced density */
4342                 STm->tape = tpnt;
4343         }
4344
4345         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4346                 STps = &(tpnt->ps[i]);
4347                 STps->rw = ST_IDLE;
4348                 STps->eof = ST_NOEOF;
4349                 STps->at_sm = 0;
4350                 STps->last_block_valid = 0;
4351                 STps->drv_block = (-1);
4352                 STps->drv_file = (-1);
4353         }
4354
4355         tpnt->current_mode = 0;
4356         tpnt->modes[0].defined = 1;
4357
4358         tpnt->density_changed = tpnt->compression_changed =
4359             tpnt->blksize_changed = 0;
4360         mutex_init(&tpnt->lock);
4361
4362         idr_preload(GFP_KERNEL);
4363         spin_lock(&st_index_lock);
4364         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4365         spin_unlock(&st_index_lock);
4366         idr_preload_end();
4367         if (error < 0) {
4368                 pr_warn("st: idr allocation failed: %d\n", error);
4369                 goto out_put_queue;
4370         }
4371         tpnt->index = error;
4372         sprintf(disk->disk_name, "st%d", tpnt->index);
4373         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4374         if (tpnt->stats == NULL) {
4375                 sdev_printk(KERN_ERR, SDp,
4376                             "st: Can't allocate statistics.\n");
4377                 goto out_idr_remove;
4378         }
4379
4380         dev_set_drvdata(dev, tpnt);
4381
4382
4383         error = create_cdevs(tpnt);
4384         if (error)
4385                 goto out_remove_devs;
4386         scsi_autopm_put_device(SDp);
4387
4388         sdev_printk(KERN_NOTICE, SDp,
4389                     "Attached scsi tape %s\n", tape_name(tpnt));
4390         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4391                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4392                     queue_dma_alignment(SDp->request_queue) + 1);
4393
4394         return 0;
4395
4396 out_remove_devs:
4397         remove_cdevs(tpnt);
4398         kfree(tpnt->stats);
4399 out_idr_remove:
4400         spin_lock(&st_index_lock);
4401         idr_remove(&st_index_idr, tpnt->index);
4402         spin_unlock(&st_index_lock);
4403 out_put_queue:
4404         blk_put_queue(disk->queue);
4405 out_put_disk:
4406         put_disk(disk);
4407         kfree(tpnt);
4408 out_buffer_free:
4409         kfree(buffer);
4410 out:
4411         scsi_autopm_put_device(SDp);
4412         return -ENODEV;
4413 };
4414
4415
4416 static int st_remove(struct device *dev)
4417 {
4418         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4419         int index = tpnt->index;
4420
4421         scsi_autopm_get_device(to_scsi_device(dev));
4422         remove_cdevs(tpnt);
4423
4424         mutex_lock(&st_ref_mutex);
4425         kref_put(&tpnt->kref, scsi_tape_release);
4426         mutex_unlock(&st_ref_mutex);
4427         spin_lock(&st_index_lock);
4428         idr_remove(&st_index_idr, index);
4429         spin_unlock(&st_index_lock);
4430         return 0;
4431 }
4432
4433 /**
4434  *      scsi_tape_release - Called to free the Scsi_Tape structure
4435  *      @kref: pointer to embedded kref
4436  *
4437  *      st_ref_mutex must be held entering this routine.  Because it is
4438  *      called on last put, you should always use the scsi_tape_get()
4439  *      scsi_tape_put() helpers which manipulate the semaphore directly
4440  *      and never do a direct kref_put().
4441  **/
4442 static void scsi_tape_release(struct kref *kref)
4443 {
4444         struct scsi_tape *tpnt = to_scsi_tape(kref);
4445         struct gendisk *disk = tpnt->disk;
4446
4447         tpnt->device = NULL;
4448
4449         if (tpnt->buffer) {
4450                 normalize_buffer(tpnt->buffer);
4451                 kfree(tpnt->buffer->reserved_pages);
4452                 kfree(tpnt->buffer);
4453         }
4454
4455         disk->private_data = NULL;
4456         put_disk(disk);
4457         kfree(tpnt->stats);
4458         kfree(tpnt);
4459         return;
4460 }
4461
4462 static struct class st_sysfs_class = {
4463         .name = "scsi_tape",
4464         .dev_groups = st_dev_groups,
4465 };
4466
4467 static int __init init_st(void)
4468 {
4469         int err;
4470
4471         validate_options();
4472
4473         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4474                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4475
4476         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4477         if (debugging) {
4478                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4479                         debugging);
4480         }
4481
4482         err = class_register(&st_sysfs_class);
4483         if (err) {
4484                 pr_err("Unable register sysfs class for SCSI tapes\n");
4485                 return err;
4486         }
4487
4488         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4489                                      ST_MAX_TAPE_ENTRIES, "st");
4490         if (err) {
4491                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4492                        SCSI_TAPE_MAJOR);
4493                 goto err_class;
4494         }
4495
4496         err = scsi_register_driver(&st_template.gendrv);
4497         if (err)
4498                 goto err_chrdev;
4499
4500         return 0;
4501
4502 err_chrdev:
4503         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4504                                  ST_MAX_TAPE_ENTRIES);
4505 err_class:
4506         class_unregister(&st_sysfs_class);
4507         return err;
4508 }
4509
4510 static void __exit exit_st(void)
4511 {
4512         scsi_unregister_driver(&st_template.gendrv);
4513         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4514                                  ST_MAX_TAPE_ENTRIES);
4515         class_unregister(&st_sysfs_class);
4516         idr_destroy(&st_index_idr);
4517         printk(KERN_INFO "st: Unloaded.\n");
4518 }
4519
4520 module_init(init_st);
4521 module_exit(exit_st);
4522
4523
4524 /* The sysfs driver interface. Read-only at the moment */
4525 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4526 {
4527         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4528 }
4529 static DRIVER_ATTR_RO(try_direct_io);
4530
4531 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4532 {
4533         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4534 }
4535 static DRIVER_ATTR_RO(fixed_buffer_size);
4536
4537 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4538 {
4539         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4540 }
4541 static DRIVER_ATTR_RO(max_sg_segs);
4542
4543 static ssize_t version_show(struct device_driver *ddd, char *buf)
4544 {
4545         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4546 }
4547 static DRIVER_ATTR_RO(version);
4548
4549 #if DEBUG
4550 static ssize_t debug_flag_store(struct device_driver *ddp,
4551         const char *buf, size_t count)
4552 {
4553 /* We only care what the first byte of the data is the rest is unused.
4554  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4555  * other values have -EINVAL returned if they are passed in.
4556  */
4557         if (count > 0) {
4558                 if (buf[0] == '0') {
4559                         debugging = NO_DEBUG;
4560                         return count;
4561                 } else if (buf[0] == '1') {
4562                         debugging = 1;
4563                         return count;
4564                 }
4565         }
4566         return -EINVAL;
4567 }
4568
4569 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4570 {
4571         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4572 }
4573 static DRIVER_ATTR_RW(debug_flag);
4574 #endif
4575
4576 static struct attribute *st_drv_attrs[] = {
4577         &driver_attr_try_direct_io.attr,
4578         &driver_attr_fixed_buffer_size.attr,
4579         &driver_attr_max_sg_segs.attr,
4580         &driver_attr_version.attr,
4581 #if DEBUG
4582         &driver_attr_debug_flag.attr,
4583 #endif
4584         NULL,
4585 };
4586 ATTRIBUTE_GROUPS(st_drv);
4587
4588 /* The sysfs simple class interface */
4589 static ssize_t
4590 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4591 {
4592         struct st_modedef *STm = dev_get_drvdata(dev);
4593         ssize_t l = 0;
4594
4595         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4596         return l;
4597 }
4598 static DEVICE_ATTR_RO(defined);
4599
4600 static ssize_t
4601 default_blksize_show(struct device *dev, struct device_attribute *attr,
4602                      char *buf)
4603 {
4604         struct st_modedef *STm = dev_get_drvdata(dev);
4605         ssize_t l = 0;
4606
4607         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4608         return l;
4609 }
4610 static DEVICE_ATTR_RO(default_blksize);
4611
4612 static ssize_t
4613 default_density_show(struct device *dev, struct device_attribute *attr,
4614                      char *buf)
4615 {
4616         struct st_modedef *STm = dev_get_drvdata(dev);
4617         ssize_t l = 0;
4618         char *fmt;
4619
4620         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4621         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4622         return l;
4623 }
4624 static DEVICE_ATTR_RO(default_density);
4625
4626 static ssize_t
4627 default_compression_show(struct device *dev, struct device_attribute *attr,
4628                          char *buf)
4629 {
4630         struct st_modedef *STm = dev_get_drvdata(dev);
4631         ssize_t l = 0;
4632
4633         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4634         return l;
4635 }
4636 static DEVICE_ATTR_RO(default_compression);
4637
4638 static ssize_t
4639 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4640 {
4641         struct st_modedef *STm = dev_get_drvdata(dev);
4642         struct scsi_tape *STp = STm->tape;
4643         int options;
4644         ssize_t l = 0;
4645
4646         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4647         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4648         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4649         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4650         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4651         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4652         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4653         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4654         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4655         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4656         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4657         options |= STm->sysv ? MT_ST_SYSV : 0;
4658         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4659         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4660         options |= STp->sili ? MT_ST_SILI : 0;
4661
4662         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4663         return l;
4664 }
4665 static DEVICE_ATTR_RO(options);
4666
4667 /* Support for tape stats */
4668
4669 /**
4670  * read_cnt_show - return read count - count of reads made from tape drive
4671  * @dev: struct device
4672  * @attr: attribute structure
4673  * @buf: buffer to return formatted data in
4674  */
4675 static ssize_t read_cnt_show(struct device *dev,
4676         struct device_attribute *attr, char *buf)
4677 {
4678         struct st_modedef *STm = dev_get_drvdata(dev);
4679
4680         return sprintf(buf, "%lld",
4681                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4682 }
4683 static DEVICE_ATTR_RO(read_cnt);
4684
4685 /**
4686  * read_byte_cnt_show - return read byte count - tape drives
4687  * may use blocks less than 512 bytes this gives the raw byte count of
4688  * of data read from the tape drive.
4689  * @dev: struct device
4690  * @attr: attribute structure
4691  * @buf: buffer to return formatted data in
4692  */
4693 static ssize_t read_byte_cnt_show(struct device *dev,
4694         struct device_attribute *attr, char *buf)
4695 {
4696         struct st_modedef *STm = dev_get_drvdata(dev);
4697
4698         return sprintf(buf, "%lld",
4699                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4700 }
4701 static DEVICE_ATTR_RO(read_byte_cnt);
4702
4703 /**
4704  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4705  * @dev: struct device
4706  * @attr: attribute structure
4707  * @buf: buffer to return formatted data in
4708  */
4709 static ssize_t read_ns_show(struct device *dev,
4710         struct device_attribute *attr, char *buf)
4711 {
4712         struct st_modedef *STm = dev_get_drvdata(dev);
4713
4714         return sprintf(buf, "%lld",
4715                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4716 }
4717 static DEVICE_ATTR_RO(read_ns);
4718
4719 /**
4720  * write_cnt_show - write count - number of user calls
4721  * to write(2) that have written data to tape.
4722  * @dev: struct device
4723  * @attr: attribute structure
4724  * @buf: buffer to return formatted data in
4725  */
4726 static ssize_t write_cnt_show(struct device *dev,
4727         struct device_attribute *attr, char *buf)
4728 {
4729         struct st_modedef *STm = dev_get_drvdata(dev);
4730
4731         return sprintf(buf, "%lld",
4732                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4733 }
4734 static DEVICE_ATTR_RO(write_cnt);
4735
4736 /**
4737  * write_byte_cnt_show - write byte count - raw count of
4738  * bytes written to tape.
4739  * @dev: struct device
4740  * @attr: attribute structure
4741  * @buf: buffer to return formatted data in
4742  */
4743 static ssize_t write_byte_cnt_show(struct device *dev,
4744         struct device_attribute *attr, char *buf)
4745 {
4746         struct st_modedef *STm = dev_get_drvdata(dev);
4747
4748         return sprintf(buf, "%lld",
4749                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4750 }
4751 static DEVICE_ATTR_RO(write_byte_cnt);
4752
4753 /**
4754  * write_ns_show - write ns - number of nanoseconds waiting on write
4755  * requests to complete.
4756  * @dev: struct device
4757  * @attr: attribute structure
4758  * @buf: buffer to return formatted data in
4759  */
4760 static ssize_t write_ns_show(struct device *dev,
4761         struct device_attribute *attr, char *buf)
4762 {
4763         struct st_modedef *STm = dev_get_drvdata(dev);
4764
4765         return sprintf(buf, "%lld",
4766                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4767 }
4768 static DEVICE_ATTR_RO(write_ns);
4769
4770 /**
4771  * in_flight_show - number of I/Os currently in flight -
4772  * in most cases this will be either 0 or 1. It may be higher if someone
4773  * has also issued other SCSI commands such as via an ioctl.
4774  * @dev: struct device
4775  * @attr: attribute structure
4776  * @buf: buffer to return formatted data in
4777  */
4778 static ssize_t in_flight_show(struct device *dev,
4779         struct device_attribute *attr, char *buf)
4780 {
4781         struct st_modedef *STm = dev_get_drvdata(dev);
4782
4783         return sprintf(buf, "%lld",
4784                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4785 }
4786 static DEVICE_ATTR_RO(in_flight);
4787
4788 /**
4789  * io_ns_show - io wait ns - this is the number of ns spent
4790  * waiting on all I/O to complete. This includes tape movement commands
4791  * such as rewinding, seeking to end of file or tape, it also includes
4792  * read and write. To determine the time spent on tape movement
4793  * subtract the read and write ns from this value.
4794  * @dev: struct device
4795  * @attr: attribute structure
4796  * @buf: buffer to return formatted data in
4797  */
4798 static ssize_t io_ns_show(struct device *dev,
4799         struct device_attribute *attr, char *buf)
4800 {
4801         struct st_modedef *STm = dev_get_drvdata(dev);
4802
4803         return sprintf(buf, "%lld",
4804                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4805 }
4806 static DEVICE_ATTR_RO(io_ns);
4807
4808 /**
4809  * other_cnt_show - other io count - this is the number of
4810  * I/O requests other than read and write requests.
4811  * Typically these are tape movement requests but will include driver
4812  * tape movement. This includes only requests issued by the st driver.
4813  * @dev: struct device
4814  * @attr: attribute structure
4815  * @buf: buffer to return formatted data in
4816  */
4817 static ssize_t other_cnt_show(struct device *dev,
4818         struct device_attribute *attr, char *buf)
4819 {
4820         struct st_modedef *STm = dev_get_drvdata(dev);
4821
4822         return sprintf(buf, "%lld",
4823                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4824 }
4825 static DEVICE_ATTR_RO(other_cnt);
4826
4827 /**
4828  * resid_cnt_show - A count of the number of times we get a residual
4829  * count - this should indicate someone issuing reads larger than the
4830  * block size on tape.
4831  * @dev: struct device
4832  * @attr: attribute structure
4833  * @buf: buffer to return formatted data in
4834  */
4835 static ssize_t resid_cnt_show(struct device *dev,
4836         struct device_attribute *attr, char *buf)
4837 {
4838         struct st_modedef *STm = dev_get_drvdata(dev);
4839
4840         return sprintf(buf, "%lld",
4841                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4842 }
4843 static DEVICE_ATTR_RO(resid_cnt);
4844
4845 static struct attribute *st_dev_attrs[] = {
4846         &dev_attr_defined.attr,
4847         &dev_attr_default_blksize.attr,
4848         &dev_attr_default_density.attr,
4849         &dev_attr_default_compression.attr,
4850         &dev_attr_options.attr,
4851         NULL,
4852 };
4853
4854 static struct attribute *st_stats_attrs[] = {
4855         &dev_attr_read_cnt.attr,
4856         &dev_attr_read_byte_cnt.attr,
4857         &dev_attr_read_ns.attr,
4858         &dev_attr_write_cnt.attr,
4859         &dev_attr_write_byte_cnt.attr,
4860         &dev_attr_write_ns.attr,
4861         &dev_attr_in_flight.attr,
4862         &dev_attr_io_ns.attr,
4863         &dev_attr_other_cnt.attr,
4864         &dev_attr_resid_cnt.attr,
4865         NULL,
4866 };
4867
4868 static struct attribute_group stats_group = {
4869         .name = "stats",
4870         .attrs = st_stats_attrs,
4871 };
4872
4873 static struct attribute_group st_group = {
4874         .attrs = st_dev_attrs,
4875 };
4876
4877 static const struct attribute_group *st_dev_groups[] = {
4878         &st_group,
4879         &stats_group,
4880         NULL,
4881 };
4882
4883 /* The following functions may be useful for a larger audience. */
4884 static int sgl_map_user_pages(struct st_buffer *STbp,
4885                               const unsigned int max_pages, unsigned long uaddr,
4886                               size_t count, int rw)
4887 {
4888         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4889         unsigned long start = uaddr >> PAGE_SHIFT;
4890         const int nr_pages = end - start;
4891         int res, i;
4892         struct page **pages;
4893         struct rq_map_data *mdata = &STbp->map_data;
4894
4895         /* User attempted Overflow! */
4896         if ((uaddr + count) < uaddr)
4897                 return -EINVAL;
4898
4899         /* Too big */
4900         if (nr_pages > max_pages)
4901                 return -ENOMEM;
4902
4903         /* Hmm? */
4904         if (count == 0)
4905                 return 0;
4906
4907         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4908         if (pages == NULL)
4909                 return -ENOMEM;
4910
4911         /* Try to fault in all of the necessary pages */
4912         /* rw==READ means read from drive, write into memory area */
4913         res = pin_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4914                                   pages);
4915
4916         /* Errors and no page mapped should return here */
4917         if (res < nr_pages)
4918                 goto out_unmap;
4919
4920         for (i=0; i < nr_pages; i++) {
4921                 /* FIXME: flush superflous for rw==READ,
4922                  * probably wrong function for rw==WRITE
4923                  */
4924                 flush_dcache_page(pages[i]);
4925         }
4926
4927         mdata->offset = uaddr & ~PAGE_MASK;
4928         STbp->mapped_pages = pages;
4929
4930         return nr_pages;
4931  out_unmap:
4932         if (res > 0) {
4933                 unpin_user_pages(pages, res);
4934                 res = 0;
4935         }
4936         kfree(pages);
4937         return res;
4938 }
4939
4940
4941 /* And unmap them... */
4942 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4943                                 const unsigned int nr_pages, int dirtied)
4944 {
4945         /* FIXME: cache flush missing for rw==READ */
4946         unpin_user_pages_dirty_lock(STbp->mapped_pages, nr_pages, dirtied);
4947
4948         kfree(STbp->mapped_pages);
4949         STbp->mapped_pages = NULL;
4950
4951         return 0;
4952 }