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/major.h>
  36 #include <linux/cdrom.h>
  37 #include <linux/ioctl.h>
  38 #include <linux/fcntl.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/blkdev.h>
  41 #include <linux/moduleparam.h>
  42 #include <linux/cdev.h>
  43 #include <linux/idr.h>
  44 #include <linux/delay.h>
  45 #include <linux/mutex.h>
  46
  47 #include <linux/uaccess.h>
  48 #include <asm/dma.h>
  49 #include <asm/unaligned.h>
  50
  51 #include <scsi/scsi.h>
  52 #include <scsi/scsi_dbg.h>
  53 #include <scsi/scsi_device.h>
  54 #include <scsi/scsi_driver.h>
  55 #include <scsi/scsi_eh.h>
  56 #include <scsi/scsi_host.h>
  57 #include <scsi/scsi_ioctl.h>
  58 #include <scsi/sg.h>
  59
  60
  61 /* The driver prints some debugging information on the console if DEBUG
  62    is defined and non-zero. */
  63 #define DEBUG 1
  64 #define NO_DEBUG 0
  65
  66 #define ST_DEB_MSG  KERN_NOTICE
  67 #if DEBUG
  68 /* The message level for the debug messages is currently set to KERN_NOTICE
  69    so that people can easily see the messages. Later when the debugging messages
  70    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  71 #define DEB(a) a
  72 #define DEBC(a) if (debugging) { a ; }
  73 #else
  74 #define DEB(a)
  75 #define DEBC(a)
  76 #endif
  77
  78 #define ST_KILOBYTE 1024
  79
  80 #include "st_options.h"
  81 #include "st.h"
  82
  83 static int buffer_kbs;
  84 static int max_sg_segs;
  85 static int try_direct_io = TRY_DIRECT_IO;
  86 static int try_rdio = 1;
  87 static int try_wdio = 1;
  88 static int debug_flag;
  89
  90 static struct class st_sysfs_class;
  91 static const struct attribute_group *st_dev_groups[];
  92 static const struct attribute_group *st_drv_groups[];
  93
  94 MODULE_AUTHOR("Kai Makisara");
  95 MODULE_DESCRIPTION("SCSI tape (st) driver");
  96 MODULE_LICENSE("GPL");
  97 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  98 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  99
 100 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
 101  * of sysfs parameters (which module_param doesn't yet support).
 102  * Sysfs parameters defined explicitly later.
 103  */
 104 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 105 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 106 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 107 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 108 module_param_named(try_direct_io, try_direct_io, int, 0);
 109 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 110 module_param_named(debug_flag, debug_flag, int, 0);
 111 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 112
 113
 114 /* Extra parameters for testing */
 115 module_param_named(try_rdio, try_rdio, int, 0);
 116 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 117 module_param_named(try_wdio, try_wdio, int, 0);
 118 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 119
 120 #ifndef MODULE
 121 static int write_threshold_kbs;  /* retained for compatibility */
 122 static struct st_dev_parm {
 123         char *name;
 124         int *val;
 125 } parms[] __initdata = {
 126         {
 127                 "buffer_kbs", &buffer_kbs
 128         },
 129         {       /* Retained for compatibility with 2.4 */
 130                 "write_threshold_kbs", &write_threshold_kbs
 131         },
 132         {
 133                 "max_sg_segs", NULL
 134         },
 135         {
 136                 "try_direct_io", &try_direct_io
 137         },
 138         {
 139                 "debug_flag", &debug_flag
 140         }
 141 };
 142 #endif
 143
 144 /* Restrict the number of modes so that names for all are assigned */
 145 #if ST_NBR_MODES > 16
 146 #error "Maximum number of modes is 16"
 147 #endif
 148 /* Bit reversed order to get same names for same minors with all
 149    mode counts */
 150 static const char *st_formats[] = {
 151         "",  "r", "k", "s", "l", "t", "o", "u",
 152         "m", "v", "p", "x", "a", "y", "q", "z"};
 153
 154 /* The default definitions have been moved to st_options.h */
 155
 156 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 157
 158 /* The buffer size should fit into the 24 bits for length in the
 159    6-byte SCSI read and write commands. */
 160 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 161 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 162 #endif
 163
 164 static int debugging = DEBUG;
 165
 166 #define MAX_RETRIES 0
 167 #define MAX_WRITE_RETRIES 0
 168 #define MAX_READY_RETRIES 0
 169 #define NO_TAPE  NOT_READY
 170
 171 #define ST_TIMEOUT (900 * HZ)
 172 #define ST_LONG_TIMEOUT (14000 * HZ)
 173
 174 /* Remove mode bits and auto-rewind bit (7) */
 175 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 176         (iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
 177 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 178
 179 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 180 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 181   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 182
 183 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 184    24 bits) */
 185 #define SET_DENS_AND_BLK 0x10001
 186
 187 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 188 static int st_max_sg_segs = ST_MAX_SG;
 189
 190 static int modes_defined;
 191
 192 static int enlarge_buffer(struct st_buffer *, int);
 193 static void clear_buffer(struct st_buffer *);
 194 static void normalize_buffer(struct st_buffer *);
 195 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 196 static int from_buffer(struct st_buffer *, char __user *, int);
 197 static void move_buffer_data(struct st_buffer *, int);
 198
 199 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 200                               unsigned long, size_t, int);
 201 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 202
 203 static int st_probe(struct device *);
 204 static int st_remove(struct device *);
 205
 206 static struct scsi_driver st_template = {
 207         .gendrv = {
 208                 .name           = "st",
 209                 .owner          = THIS_MODULE,
 210                 .probe          = st_probe,
 211                 .remove         = st_remove,
 212                 .groups         = st_drv_groups,
 213         },
 214 };
 215
 216 static int st_compression(struct scsi_tape *, int);
 217
 218 static int find_partition(struct scsi_tape *);
 219 static int switch_partition(struct scsi_tape *);
 220
 221 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 222
 223 static void scsi_tape_release(struct kref *);
 224
 225 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 226
 227 static DEFINE_MUTEX(st_ref_mutex);
 228 static DEFINE_SPINLOCK(st_index_lock);
 229 static DEFINE_SPINLOCK(st_use_lock);
 230 static DEFINE_IDR(st_index_idr);
 231
 232
 233 \f
 234 #ifndef SIGS_FROM_OSST
 235 #define SIGS_FROM_OSST \
 236         {"OnStream", "SC-", "", "osst"}, \
 237         {"OnStream", "DI-", "", "osst"}, \
 238         {"OnStream", "DP-", "", "osst"}, \
 239         {"OnStream", "USB", "", "osst"}, \
 240         {"OnStream", "FW-", "", "osst"}
 241 #endif
 242
 243 static struct scsi_tape *scsi_tape_get(int dev)
 244 {
 245         struct scsi_tape *STp = NULL;
 246
 247         mutex_lock(&st_ref_mutex);
 248         spin_lock(&st_index_lock);
 249
 250         STp = idr_find(&st_index_idr, dev);
 251         if (!STp) goto out;
 252
 253         kref_get(&STp->kref);
 254
 255         if (!STp->device)
 256                 goto out_put;
 257
 258         if (scsi_device_get(STp->device))
 259                 goto out_put;
 260
 261         goto out;
 262
 263 out_put:
 264         kref_put(&STp->kref, scsi_tape_release);
 265         STp = NULL;
 266 out:
 267         spin_unlock(&st_index_lock);
 268         mutex_unlock(&st_ref_mutex);
 269         return STp;
 270 }
 271
 272 static void scsi_tape_put(struct scsi_tape *STp)
 273 {
 274         struct scsi_device *sdev = STp->device;
 275
 276         mutex_lock(&st_ref_mutex);
 277         kref_put(&STp->kref, scsi_tape_release);
 278         scsi_device_put(sdev);
 279         mutex_unlock(&st_ref_mutex);
 280 }
 281
 282 struct st_reject_data {
 283         char *vendor;
 284         char *model;
 285         char *rev;
 286         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 287 };
 288
 289 static struct st_reject_data reject_list[] = {
 290         /* {"XXX", "Yy-", "", NULL},  example */
 291         SIGS_FROM_OSST,
 292         {NULL, }};
 293
 294 /* If the device signature is on the list of incompatible drives, the
 295    function returns a pointer to the name of the correct driver (if known) */
 296 static char * st_incompatible(struct scsi_device* SDp)
 297 {
 298         struct st_reject_data *rp;
 299
 300         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 301                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 302                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 303                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 304                         if (rp->driver_hint)
 305                                 return rp->driver_hint;
 306                         else
 307                                 return "unknown";
 308                 }
 309         return NULL;
 310 }
 311 \f
 312
 313 #define st_printk(prefix, t, fmt, a...) \
 314         sdev_prefix_printk(prefix, (t)->device, (t)->name, fmt, ##a)
 315 #ifdef DEBUG
 316 #define DEBC_printk(t, fmt, a...) \
 317         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 318 #else
 319 #define DEBC_printk(t, fmt, a...)
 320 #endif
 321
 322 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 323 {
 324         const u8 *ucp;
 325         const u8 *sense = SRpnt->sense;
 326
 327         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 328                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 329         s->flags = 0;
 330
 331         if (s->have_sense) {
 332                 s->deferred = 0;
 333                 s->remainder_valid =
 334                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 335                 switch (sense[0] & 0x7f) {
 336                 case 0x71:
 337                         s->deferred = 1;
 338                         fallthrough;
 339                 case 0x70:
 340                         s->fixed_format = 1;
 341                         s->flags = sense[2] & 0xe0;
 342                         break;
 343                 case 0x73:
 344                         s->deferred = 1;
 345                         fallthrough;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = STp->name;
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0, host bt 0x%x).\n",
 390                                result, host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417         if (cmdstatp->have_sense && scode == UNIT_ATTENTION && cmdstatp->sense_hdr.asc == 0x29)
 418                 STp->pos_unknown = 1; /* ASC => power on / reset */
 419
 420         STp->pos_unknown |= STp->device->was_reset;
 421
 422         if (cmdstatp->have_sense &&
 423             scode == RECOVERED_ERROR
 424 #if ST_RECOVERED_WRITE_FATAL
 425             && SRpnt->cmd[0] != WRITE_6
 426             && SRpnt->cmd[0] != WRITE_FILEMARKS
 427 #endif
 428             ) {
 429                 STp->recover_count++;
 430                 STp->recover_reg++;
 431
 432                 DEB(
 433                 if (debugging) {
 434                         if (SRpnt->cmd[0] == READ_6)
 435                                 stp = "read";
 436                         else if (SRpnt->cmd[0] == WRITE_6)
 437                                 stp = "write";
 438                         else
 439                                 stp = "ioctl";
 440                         st_printk(ST_DEB_MSG, STp,
 441                                   "Recovered %s error (%d).\n",
 442                                   stp, STp->recover_count);
 443                 } ) /* end DEB */
 444
 445                 if (cmdstatp->flags == 0)
 446                         return 0;
 447         }
 448         return (-EIO);
 449 }
 450
 451 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 452 {
 453         struct st_request *streq;
 454
 455         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 456         if (streq)
 457                 streq->stp = stp;
 458         else {
 459                 st_printk(KERN_ERR, stp,
 460                           "Can't get SCSI request.\n");
 461                 if (signal_pending(current))
 462                         stp->buffer->syscall_result = -EINTR;
 463                 else
 464                         stp->buffer->syscall_result = -EBUSY;
 465         }
 466
 467         return streq;
 468 }
 469
 470 static void st_release_request(struct st_request *streq)
 471 {
 472         kfree(streq);
 473 }
 474
 475 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 476 {
 477         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 478         ktime_t now;
 479
 480         now = ktime_get();
 481         if (scmd->cmnd[0] == WRITE_6) {
 482                 now = ktime_sub(now, STp->stats->write_time);
 483                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 484                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 485                 atomic64_inc(&STp->stats->write_cnt);
 486                 if (scmd->result) {
 487                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 488                                 - STp->buffer->cmdstat.residual,
 489                                 &STp->stats->write_byte_cnt);
 490                         if (STp->buffer->cmdstat.residual > 0)
 491                                 atomic64_inc(&STp->stats->resid_cnt);
 492                 } else
 493                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 494                                 &STp->stats->write_byte_cnt);
 495         } else if (scmd->cmnd[0] == READ_6) {
 496                 now = ktime_sub(now, STp->stats->read_time);
 497                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 498                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 499                 atomic64_inc(&STp->stats->read_cnt);
 500                 if (scmd->result) {
 501                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 502                                 - STp->buffer->cmdstat.residual,
 503                                 &STp->stats->read_byte_cnt);
 504                         if (STp->buffer->cmdstat.residual > 0)
 505                                 atomic64_inc(&STp->stats->resid_cnt);
 506                 } else
 507                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 508                                 &STp->stats->read_byte_cnt);
 509         } else {
 510                 now = ktime_sub(now, STp->stats->other_time);
 511                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 512                 atomic64_inc(&STp->stats->other_cnt);
 513         }
 514         atomic64_dec(&STp->stats->in_flight);
 515 }
 516
 517 static enum rq_end_io_ret st_scsi_execute_end(struct request *req,
 518                                               blk_status_t status)
 519 {
 520         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 521         struct st_request *SRpnt = req->end_io_data;
 522         struct scsi_tape *STp = SRpnt->stp;
 523         struct bio *tmp;
 524
 525         STp->buffer->cmdstat.midlevel_result = SRpnt->result = scmd->result;
 526         STp->buffer->cmdstat.residual = scmd->resid_len;
 527
 528         st_do_stats(STp, req);
 529
 530         tmp = SRpnt->bio;
 531         if (scmd->sense_len)
 532                 memcpy(SRpnt->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
 533         if (SRpnt->waiting)
 534                 complete(SRpnt->waiting);
 535
 536         blk_rq_unmap_user(tmp);
 537         blk_mq_free_request(req);
 538         return RQ_END_IO_NONE;
 539 }
 540
 541 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 542                            int data_direction, void *buffer, unsigned bufflen,
 543                            int timeout, int retries)
 544 {
 545         struct request *req;
 546         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 547         int err = 0;
 548         struct scsi_tape *STp = SRpnt->stp;
 549         struct scsi_cmnd *scmd;
 550
 551         req = scsi_alloc_request(SRpnt->stp->device->request_queue,
 552                         data_direction == DMA_TO_DEVICE ?
 553                         REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
 554         if (IS_ERR(req))
 555                 return PTR_ERR(req);
 556         scmd = blk_mq_rq_to_pdu(req);
 557         req->rq_flags |= RQF_QUIET;
 558
 559         mdata->null_mapped = 1;
 560
 561         if (bufflen) {
 562                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 563                                       GFP_KERNEL);
 564                 if (err) {
 565                         blk_mq_free_request(req);
 566                         return err;
 567                 }
 568         }
 569
 570         atomic64_inc(&STp->stats->in_flight);
 571         if (cmd[0] == WRITE_6) {
 572                 atomic_set(&STp->stats->last_write_size, bufflen);
 573                 STp->stats->write_time = ktime_get();
 574         } else if (cmd[0] == READ_6) {
 575                 atomic_set(&STp->stats->last_read_size, bufflen);
 576                 STp->stats->read_time = ktime_get();
 577         } else {
 578                 STp->stats->other_time = ktime_get();
 579         }
 580
 581         SRpnt->bio = req->bio;
 582         scmd->cmd_len = COMMAND_SIZE(cmd[0]);
 583         memcpy(scmd->cmnd, cmd, scmd->cmd_len);
 584         req->timeout = timeout;
 585         scmd->allowed = retries;
 586         req->end_io = st_scsi_execute_end;
 587         req->end_io_data = SRpnt;
 588
 589         blk_execute_rq_nowait(req, true);
 590         return 0;
 591 }
 592
 593 /* Do the scsi command. Waits until command performed if do_wait is true.
 594    Otherwise write_behind_check() is used to check that the command
 595    has finished. */
 596 static struct st_request *
 597 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 598            int bytes, int direction, int timeout, int retries, int do_wait)
 599 {
 600         struct completion *waiting;
 601         struct rq_map_data *mdata = &STp->buffer->map_data;
 602         int ret;
 603
 604         /* if async, make sure there's no command outstanding */
 605         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 606                 st_printk(KERN_ERR, STp,
 607                           "Async command already active.\n");
 608                 if (signal_pending(current))
 609                         (STp->buffer)->syscall_result = (-EINTR);
 610                 else
 611                         (STp->buffer)->syscall_result = (-EBUSY);
 612                 return NULL;
 613         }
 614
 615         if (!SRpnt) {
 616                 SRpnt = st_allocate_request(STp);
 617                 if (!SRpnt)
 618                         return NULL;
 619         }
 620
 621         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 622            which IO is outstanding. It's nulled out when the IO completes. */
 623         if (!do_wait)
 624                 (STp->buffer)->last_SRpnt = SRpnt;
 625
 626         waiting = &STp->wait;
 627         init_completion(waiting);
 628         SRpnt->waiting = waiting;
 629
 630         if (STp->buffer->do_dio) {
 631                 mdata->page_order = 0;
 632                 mdata->nr_entries = STp->buffer->sg_segs;
 633                 mdata->pages = STp->buffer->mapped_pages;
 634         } else {
 635                 mdata->page_order = STp->buffer->reserved_page_order;
 636                 mdata->nr_entries =
 637                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 638                 mdata->pages = STp->buffer->reserved_pages;
 639                 mdata->offset = 0;
 640         }
 641
 642         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 643         STp->buffer->cmdstat.have_sense = 0;
 644         STp->buffer->syscall_result = 0;
 645
 646         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 647                               retries);
 648         if (ret) {
 649                 /* could not allocate the buffer or request was too large */
 650                 (STp->buffer)->syscall_result = (-EBUSY);
 651                 (STp->buffer)->last_SRpnt = NULL;
 652         } else if (do_wait) {
 653                 wait_for_completion(waiting);
 654                 SRpnt->waiting = NULL;
 655                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 656         }
 657
 658         return SRpnt;
 659 }
 660
 661
 662 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 663    write has been correct but EOM early warning reached, -EIO if write ended in
 664    error or zero if write successful. Asynchronous writes are used only in
 665    variable block mode. */
 666 static int write_behind_check(struct scsi_tape * STp)
 667 {
 668         int retval = 0;
 669         struct st_buffer *STbuffer;
 670         struct st_partstat *STps;
 671         struct st_cmdstatus *cmdstatp;
 672         struct st_request *SRpnt;
 673
 674         STbuffer = STp->buffer;
 675         if (!STbuffer->writing)
 676                 return 0;
 677
 678         DEB(
 679         if (STp->write_pending)
 680                 STp->nbr_waits++;
 681         else
 682                 STp->nbr_finished++;
 683         ) /* end DEB */
 684
 685         wait_for_completion(&(STp->wait));
 686         SRpnt = STbuffer->last_SRpnt;
 687         STbuffer->last_SRpnt = NULL;
 688         SRpnt->waiting = NULL;
 689
 690         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 691         st_release_request(SRpnt);
 692
 693         STbuffer->buffer_bytes -= STbuffer->writing;
 694         STps = &(STp->ps[STp->partition]);
 695         if (STps->drv_block >= 0) {
 696                 if (STp->block_size == 0)
 697                         STps->drv_block++;
 698                 else
 699                         STps->drv_block += STbuffer->writing / STp->block_size;
 700         }
 701
 702         cmdstatp = &STbuffer->cmdstat;
 703         if (STbuffer->syscall_result) {
 704                 retval = -EIO;
 705                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 706                     (cmdstatp->flags & SENSE_EOM) &&
 707                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 708                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 709                         /* EOM at write-behind, has all data been written? */
 710                         if (!cmdstatp->remainder_valid ||
 711                             cmdstatp->uremainder64 == 0)
 712                                 retval = -ENOSPC;
 713                 }
 714                 if (retval == -EIO)
 715                         STps->drv_block = -1;
 716         }
 717         STbuffer->writing = 0;
 718
 719         DEB(if (debugging && retval)
 720                     st_printk(ST_DEB_MSG, STp,
 721                                 "Async write error %x, return value %d.\n",
 722                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 723
 724         return retval;
 725 }
 726
 727
 728 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 729    it messes up the block number). */
 730 static int cross_eof(struct scsi_tape * STp, int forward)
 731 {
 732         struct st_request *SRpnt;
 733         unsigned char cmd[MAX_COMMAND_SIZE];
 734
 735         cmd[0] = SPACE;
 736         cmd[1] = 0x01;          /* Space FileMarks */
 737         if (forward) {
 738                 cmd[2] = cmd[3] = 0;
 739                 cmd[4] = 1;
 740         } else
 741                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 742         cmd[5] = 0;
 743
 744         DEBC_printk(STp, "Stepping over filemark %s.\n",
 745                     forward ? "forward" : "backward");
 746
 747         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 748                            STp->device->request_queue->rq_timeout,
 749                            MAX_RETRIES, 1);
 750         if (!SRpnt)
 751                 return (STp->buffer)->syscall_result;
 752
 753         st_release_request(SRpnt);
 754         SRpnt = NULL;
 755
 756         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 757                 st_printk(KERN_ERR, STp,
 758                           "Stepping over filemark %s failed.\n",
 759                           forward ? "forward" : "backward");
 760
 761         return (STp->buffer)->syscall_result;
 762 }
 763
 764
 765 /* Flush the write buffer (never need to write if variable blocksize). */
 766 static int st_flush_write_buffer(struct scsi_tape * STp)
 767 {
 768         int transfer, blks;
 769         int result;
 770         unsigned char cmd[MAX_COMMAND_SIZE];
 771         struct st_request *SRpnt;
 772         struct st_partstat *STps;
 773
 774         result = write_behind_check(STp);
 775         if (result)
 776                 return result;
 777
 778         result = 0;
 779         if (STp->dirty == 1) {
 780
 781                 transfer = STp->buffer->buffer_bytes;
 782                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 783
 784                 memset(cmd, 0, MAX_COMMAND_SIZE);
 785                 cmd[0] = WRITE_6;
 786                 cmd[1] = 1;
 787                 blks = transfer / STp->block_size;
 788                 cmd[2] = blks >> 16;
 789                 cmd[3] = blks >> 8;
 790                 cmd[4] = blks;
 791
 792                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 793                                    STp->device->request_queue->rq_timeout,
 794                                    MAX_WRITE_RETRIES, 1);
 795                 if (!SRpnt)
 796                         return (STp->buffer)->syscall_result;
 797
 798                 STps = &(STp->ps[STp->partition]);
 799                 if ((STp->buffer)->syscall_result != 0) {
 800                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 801
 802                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 803                             (cmdstatp->flags & SENSE_EOM) &&
 804                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 805                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 806                             (!cmdstatp->remainder_valid ||
 807                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 808                                 STp->dirty = 0;
 809                                 (STp->buffer)->buffer_bytes = 0;
 810                                 if (STps->drv_block >= 0)
 811                                         STps->drv_block += blks;
 812                                 result = (-ENOSPC);
 813                         } else {
 814                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 815                                 STps->drv_block = (-1);
 816                                 result = (-EIO);
 817                         }
 818                 } else {
 819                         if (STps->drv_block >= 0)
 820                                 STps->drv_block += blks;
 821                         STp->dirty = 0;
 822                         (STp->buffer)->buffer_bytes = 0;
 823                 }
 824                 st_release_request(SRpnt);
 825                 SRpnt = NULL;
 826         }
 827         return result;
 828 }
 829
 830
 831 /* Flush the tape buffer. The tape will be positioned correctly unless
 832    seek_next is true. */
 833 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 834 {
 835         int backspace, result;
 836         struct st_partstat *STps;
 837
 838         /*
 839          * If there was a bus reset, block further access
 840          * to this device.
 841          */
 842         if (STp->pos_unknown)
 843                 return (-EIO);
 844
 845         if (STp->ready != ST_READY)
 846                 return 0;
 847         STps = &(STp->ps[STp->partition]);
 848         if (STps->rw == ST_WRITING)     /* Writing */
 849                 return st_flush_write_buffer(STp);
 850
 851         if (STp->block_size == 0)
 852                 return 0;
 853
 854         backspace = ((STp->buffer)->buffer_bytes +
 855                      (STp->buffer)->read_pointer) / STp->block_size -
 856             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 857             STp->block_size;
 858         (STp->buffer)->buffer_bytes = 0;
 859         (STp->buffer)->read_pointer = 0;
 860         result = 0;
 861         if (!seek_next) {
 862                 if (STps->eof == ST_FM_HIT) {
 863                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 864                         if (!result)
 865                                 STps->eof = ST_NOEOF;
 866                         else {
 867                                 if (STps->drv_file >= 0)
 868                                         STps->drv_file++;
 869                                 STps->drv_block = 0;
 870                         }
 871                 }
 872                 if (!result && backspace > 0)
 873                         result = st_int_ioctl(STp, MTBSR, backspace);
 874         } else if (STps->eof == ST_FM_HIT) {
 875                 if (STps->drv_file >= 0)
 876                         STps->drv_file++;
 877                 STps->drv_block = 0;
 878                 STps->eof = ST_NOEOF;
 879         }
 880         return result;
 881
 882 }
 883 \f
 884 /* Set the mode parameters */
 885 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 886 {
 887         int set_it = 0;
 888         unsigned long arg;
 889
 890         if (!STp->density_changed &&
 891             STm->default_density >= 0 &&
 892             STm->default_density != STp->density) {
 893                 arg = STm->default_density;
 894                 set_it = 1;
 895         } else
 896                 arg = STp->density;
 897         arg <<= MT_ST_DENSITY_SHIFT;
 898         if (!STp->blksize_changed &&
 899             STm->default_blksize >= 0 &&
 900             STm->default_blksize != STp->block_size) {
 901                 arg |= STm->default_blksize;
 902                 set_it = 1;
 903         } else
 904                 arg |= STp->block_size;
 905         if (set_it &&
 906             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 907                 st_printk(KERN_WARNING, STp,
 908                           "Can't set default block size to %d bytes "
 909                           "and density %x.\n",
 910                           STm->default_blksize, STm->default_density);
 911                 if (modes_defined)
 912                         return (-EINVAL);
 913         }
 914         return 0;
 915 }
 916
 917
 918 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 919 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 920 {
 921         int retval;
 922
 923         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 924
 925         retval = scsi_set_medium_removal(STp->device,
 926                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 927         if (!retval)
 928                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 929         else
 930                 STp->door_locked = ST_LOCK_FAILS;
 931         return retval;
 932 }
 933
 934
 935 /* Set the internal state after reset */
 936 static void reset_state(struct scsi_tape *STp)
 937 {
 938         int i;
 939         struct st_partstat *STps;
 940
 941         STp->pos_unknown = 0;
 942         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 943                 STps = &(STp->ps[i]);
 944                 STps->rw = ST_IDLE;
 945                 STps->eof = ST_NOEOF;
 946                 STps->at_sm = 0;
 947                 STps->last_block_valid = 0;
 948                 STps->drv_block = -1;
 949                 STps->drv_file = -1;
 950         }
 951         if (STp->can_partitions) {
 952                 STp->partition = find_partition(STp);
 953                 if (STp->partition < 0)
 954                         STp->partition = 0;
 955                 STp->new_partition = STp->partition;
 956         }
 957 }
 958 \f
 959 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 960    error code. */
 961 #define CHKRES_READY       0
 962 #define CHKRES_NEW_SESSION 1
 963 #define CHKRES_NOT_READY   2
 964 #define CHKRES_NO_TAPE     3
 965
 966 #define MAX_ATTENTIONS    10
 967
 968 static int test_ready(struct scsi_tape *STp, int do_wait)
 969 {
 970         int attentions, waits, max_wait, scode;
 971         int retval = CHKRES_READY, new_session = 0;
 972         unsigned char cmd[MAX_COMMAND_SIZE];
 973         struct st_request *SRpnt = NULL;
 974         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 975
 976         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 977
 978         for (attentions=waits=0; ; ) {
 979                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 980                 cmd[0] = TEST_UNIT_READY;
 981                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 982                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 983
 984                 if (!SRpnt) {
 985                         retval = (STp->buffer)->syscall_result;
 986                         break;
 987                 }
 988
 989                 if (cmdstatp->have_sense) {
 990
 991                         scode = cmdstatp->sense_hdr.sense_key;
 992
 993                         if (scode == UNIT_ATTENTION) { /* New media? */
 994                                 new_session = 1;
 995                                 if (attentions < MAX_ATTENTIONS) {
 996                                         attentions++;
 997                                         continue;
 998                                 }
 999                                 else {
1000                                         retval = (-EIO);
1001                                         break;
1002                                 }
1003                         }
1004
1005                         if (scode == NOT_READY) {
1006                                 if (waits < max_wait) {
1007                                         if (msleep_interruptible(1000)) {
1008                                                 retval = (-EINTR);
1009                                                 break;
1010                                         }
1011                                         waits++;
1012                                         continue;
1013                                 }
1014                                 else {
1015                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1016                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1017                                                 retval = CHKRES_NO_TAPE;
1018                                         else
1019                                                 retval = CHKRES_NOT_READY;
1020                                         break;
1021                                 }
1022                         }
1023                 }
1024
1025                 retval = (STp->buffer)->syscall_result;
1026                 if (!retval)
1027                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1028                 break;
1029         }
1030
1031         if (SRpnt != NULL)
1032                 st_release_request(SRpnt);
1033         return retval;
1034 }
1035
1036
1037 /* See if the drive is ready and gather information about the tape. Return values:
1038    < 0   negative error code from errno.h
1039    0     drive ready
1040    1     drive not ready (possibly no tape)
1041 */
1042 static int check_tape(struct scsi_tape *STp, struct file *filp)
1043 {
1044         int i, retval, new_session = 0, do_wait;
1045         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1046         unsigned short st_flags = filp->f_flags;
1047         struct st_request *SRpnt = NULL;
1048         struct st_modedef *STm;
1049         struct st_partstat *STps;
1050         struct inode *inode = file_inode(filp);
1051         int mode = TAPE_MODE(inode);
1052
1053         STp->ready = ST_READY;
1054
1055         if (mode != STp->current_mode) {
1056                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1057                             STp->current_mode, mode);
1058                 new_session = 1;
1059                 STp->current_mode = mode;
1060         }
1061         STm = &(STp->modes[STp->current_mode]);
1062
1063         saved_cleaning = STp->cleaning_req;
1064         STp->cleaning_req = 0;
1065
1066         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1067         retval = test_ready(STp, do_wait);
1068
1069         if (retval < 0)
1070             goto err_out;
1071
1072         if (retval == CHKRES_NEW_SESSION) {
1073                 STp->pos_unknown = 0;
1074                 STp->partition = STp->new_partition = 0;
1075                 if (STp->can_partitions)
1076                         STp->nbr_partitions = 1; /* This guess will be updated later
1077                                                     if necessary */
1078                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1079                         STps = &(STp->ps[i]);
1080                         STps->rw = ST_IDLE;
1081                         STps->eof = ST_NOEOF;
1082                         STps->at_sm = 0;
1083                         STps->last_block_valid = 0;
1084                         STps->drv_block = 0;
1085                         STps->drv_file = 0;
1086                 }
1087                 new_session = 1;
1088         }
1089         else {
1090                 STp->cleaning_req |= saved_cleaning;
1091
1092                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1093                         if (retval == CHKRES_NO_TAPE)
1094                                 STp->ready = ST_NO_TAPE;
1095                         else
1096                                 STp->ready = ST_NOT_READY;
1097
1098                         STp->density = 0;       /* Clear the erroneous "residue" */
1099                         STp->write_prot = 0;
1100                         STp->block_size = 0;
1101                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1102                         STp->partition = STp->new_partition = 0;
1103                         STp->door_locked = ST_UNLOCKED;
1104                         return CHKRES_NOT_READY;
1105                 }
1106         }
1107
1108         if (STp->omit_blklims)
1109                 STp->min_block = STp->max_block = (-1);
1110         else {
1111                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1112                 cmd[0] = READ_BLOCK_LIMITS;
1113
1114                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1115                                    STp->device->request_queue->rq_timeout,
1116                                    MAX_READY_RETRIES, 1);
1117                 if (!SRpnt) {
1118                         retval = (STp->buffer)->syscall_result;
1119                         goto err_out;
1120                 }
1121
1122                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1123                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1124                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1125                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1126                             (STp->buffer)->b_data[5];
1127                         if ( DEB( debugging || ) !STp->inited)
1128                                 st_printk(KERN_INFO, STp,
1129                                           "Block limits %d - %d bytes.\n",
1130                                           STp->min_block, STp->max_block);
1131                 } else {
1132                         STp->min_block = STp->max_block = (-1);
1133                         DEBC_printk(STp, "Can't read block limits.\n");
1134                 }
1135         }
1136
1137         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1138         cmd[0] = MODE_SENSE;
1139         cmd[4] = 12;
1140
1141         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1142                            STp->device->request_queue->rq_timeout,
1143                            MAX_READY_RETRIES, 1);
1144         if (!SRpnt) {
1145                 retval = (STp->buffer)->syscall_result;
1146                 goto err_out;
1147         }
1148
1149         if ((STp->buffer)->syscall_result != 0) {
1150                 DEBC_printk(STp, "No Mode Sense.\n");
1151                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1152                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1153                 STp->drv_write_prot = 0;
1154         } else {
1155                 DEBC_printk(STp,"Mode sense. Length %d, "
1156                             "medium %x, WBS %x, BLL %d\n",
1157                             (STp->buffer)->b_data[0],
1158                             (STp->buffer)->b_data[1],
1159                             (STp->buffer)->b_data[2],
1160                             (STp->buffer)->b_data[3]);
1161
1162                 if ((STp->buffer)->b_data[3] >= 8) {
1163                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1164                         STp->density = (STp->buffer)->b_data[4];
1165                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1166                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1167                         DEBC_printk(STp, "Density %x, tape length: %x, "
1168                                     "drv buffer: %d\n",
1169                                     STp->density,
1170                                     (STp->buffer)->b_data[5] * 65536 +
1171                                     (STp->buffer)->b_data[6] * 256 +
1172                                     (STp->buffer)->b_data[7],
1173                                     STp->drv_buffer);
1174                 }
1175                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1176                 if (!STp->drv_buffer && STp->immediate_filemark) {
1177                         st_printk(KERN_WARNING, STp,
1178                                   "non-buffered tape: disabling "
1179                                   "writing immediate filemarks\n");
1180                         STp->immediate_filemark = 0;
1181                 }
1182         }
1183         st_release_request(SRpnt);
1184         SRpnt = NULL;
1185         STp->inited = 1;
1186
1187         if (STp->block_size > 0)
1188                 (STp->buffer)->buffer_blocks =
1189                         (STp->buffer)->buffer_size / STp->block_size;
1190         else
1191                 (STp->buffer)->buffer_blocks = 1;
1192         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1193
1194         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1195                     STp->block_size, (STp->buffer)->buffer_size,
1196                     (STp->buffer)->buffer_blocks);
1197
1198         if (STp->drv_write_prot) {
1199                 STp->write_prot = 1;
1200
1201                 DEBC_printk(STp, "Write protected\n");
1202
1203                 if (do_wait &&
1204                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1205                      (st_flags & O_ACCMODE) == O_RDWR)) {
1206                         retval = (-EROFS);
1207                         goto err_out;
1208                 }
1209         }
1210
1211         if (STp->can_partitions && STp->nbr_partitions < 1) {
1212                 /* This code is reached when the device is opened for the first time
1213                    after the driver has been initialized with tape in the drive and the
1214                    partition support has been enabled. */
1215                 DEBC_printk(STp, "Updating partition number in status.\n");
1216                 if ((STp->partition = find_partition(STp)) < 0) {
1217                         retval = STp->partition;
1218                         goto err_out;
1219                 }
1220                 STp->new_partition = STp->partition;
1221                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1222         }
1223
1224         if (new_session) {      /* Change the drive parameters for the new mode */
1225                 STp->density_changed = STp->blksize_changed = 0;
1226                 STp->compression_changed = 0;
1227                 if (!(STm->defaults_for_writes) &&
1228                     (retval = set_mode_densblk(STp, STm)) < 0)
1229                     goto err_out;
1230
1231                 if (STp->default_drvbuffer != 0xff) {
1232                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1233                                 st_printk(KERN_WARNING, STp,
1234                                           "Can't set default drive "
1235                                           "buffering to %d.\n",
1236                                           STp->default_drvbuffer);
1237                 }
1238         }
1239
1240         return CHKRES_READY;
1241
1242  err_out:
1243         return retval;
1244 }
1245
1246
1247 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1248    module count. */
1249 static int st_open(struct inode *inode, struct file *filp)
1250 {
1251         int i, retval = (-EIO);
1252         int resumed = 0;
1253         struct scsi_tape *STp;
1254         struct st_partstat *STps;
1255         int dev = TAPE_NR(inode);
1256
1257         /*
1258          * We really want to do nonseekable_open(inode, filp); here, but some
1259          * versions of tar incorrectly call lseek on tapes and bail out if that
1260          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1261          */
1262         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1263
1264         if (!(STp = scsi_tape_get(dev))) {
1265                 return -ENXIO;
1266         }
1267
1268         filp->private_data = STp;
1269
1270         spin_lock(&st_use_lock);
1271         if (STp->in_use) {
1272                 spin_unlock(&st_use_lock);
1273                 DEBC_printk(STp, "Device already in use.\n");
1274                 scsi_tape_put(STp);
1275                 return (-EBUSY);
1276         }
1277
1278         STp->in_use = 1;
1279         spin_unlock(&st_use_lock);
1280         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1281
1282         if (scsi_autopm_get_device(STp->device) < 0) {
1283                 retval = -EIO;
1284                 goto err_out;
1285         }
1286         resumed = 1;
1287         if (!scsi_block_when_processing_errors(STp->device)) {
1288                 retval = (-ENXIO);
1289                 goto err_out;
1290         }
1291
1292         /* See that we have at least a one page buffer available */
1293         if (!enlarge_buffer(STp->buffer, PAGE_SIZE)) {
1294                 st_printk(KERN_WARNING, STp,
1295                           "Can't allocate one page tape buffer.\n");
1296                 retval = (-EOVERFLOW);
1297                 goto err_out;
1298         }
1299
1300         (STp->buffer)->cleared = 0;
1301         (STp->buffer)->writing = 0;
1302         (STp->buffer)->syscall_result = 0;
1303
1304         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1305
1306         STp->dirty = 0;
1307         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1308                 STps = &(STp->ps[i]);
1309                 STps->rw = ST_IDLE;
1310         }
1311         STp->try_dio_now = STp->try_dio;
1312         STp->recover_count = 0;
1313         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1314              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1315
1316         retval = check_tape(STp, filp);
1317         if (retval < 0)
1318                 goto err_out;
1319         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1320             retval != CHKRES_READY) {
1321                 if (STp->ready == NO_TAPE)
1322                         retval = (-ENOMEDIUM);
1323                 else
1324                         retval = (-EIO);
1325                 goto err_out;
1326         }
1327         return 0;
1328
1329  err_out:
1330         normalize_buffer(STp->buffer);
1331         spin_lock(&st_use_lock);
1332         STp->in_use = 0;
1333         spin_unlock(&st_use_lock);
1334         if (resumed)
1335                 scsi_autopm_put_device(STp->device);
1336         scsi_tape_put(STp);
1337         return retval;
1338
1339 }
1340 \f
1341
1342 /* Flush the tape buffer before close */
1343 static int st_flush(struct file *filp, fl_owner_t id)
1344 {
1345         int result = 0, result2;
1346         unsigned char cmd[MAX_COMMAND_SIZE];
1347         struct st_request *SRpnt;
1348         struct scsi_tape *STp = filp->private_data;
1349         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1350         struct st_partstat *STps = &(STp->ps[STp->partition]);
1351
1352         if (file_count(filp) > 1)
1353                 return 0;
1354
1355         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1356                 result = st_flush_write_buffer(STp);
1357                 if (result != 0 && result != (-ENOSPC))
1358                         goto out;
1359         }
1360
1361         if (STp->can_partitions &&
1362             (result2 = switch_partition(STp)) < 0) {
1363                 DEBC_printk(STp, "switch_partition at close failed.\n");
1364                 if (result == 0)
1365                         result = result2;
1366                 goto out;
1367         }
1368
1369         DEBC( if (STp->nbr_requests)
1370                 st_printk(KERN_DEBUG, STp,
1371                           "Number of r/w requests %d, dio used in %d, "
1372                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1373                           STp->nbr_pages));
1374
1375         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1376                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1377
1378 #if DEBUG
1379                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1380                             STp->nbr_waits, STp->nbr_finished);
1381 #endif
1382                 memset(cmd, 0, MAX_COMMAND_SIZE);
1383                 cmd[0] = WRITE_FILEMARKS;
1384                 if (STp->immediate_filemark)
1385                         cmd[1] = 1;
1386                 cmd[4] = 1 + STp->two_fm;
1387
1388                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1389                                    STp->device->request_queue->rq_timeout,
1390                                    MAX_WRITE_RETRIES, 1);
1391                 if (!SRpnt) {
1392                         result = (STp->buffer)->syscall_result;
1393                         goto out;
1394                 }
1395
1396                 if (STp->buffer->syscall_result == 0 ||
1397                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1398                      (cmdstatp->flags & SENSE_EOM) &&
1399                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1400                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1401                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1402                         /* Write successful at EOM */
1403                         st_release_request(SRpnt);
1404                         SRpnt = NULL;
1405                         if (STps->drv_file >= 0)
1406                                 STps->drv_file++;
1407                         STps->drv_block = 0;
1408                         if (STp->two_fm)
1409                                 cross_eof(STp, 0);
1410                         STps->eof = ST_FM;
1411                 }
1412                 else { /* Write error */
1413                         st_release_request(SRpnt);
1414                         SRpnt = NULL;
1415                         st_printk(KERN_ERR, STp,
1416                                   "Error on write filemark.\n");
1417                         if (result == 0)
1418                                 result = (-EIO);
1419                 }
1420
1421                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1422         } else if (!STp->rew_at_close) {
1423                 STps = &(STp->ps[STp->partition]);
1424                 if (!STm->sysv || STps->rw != ST_READING) {
1425                         if (STp->can_bsr)
1426                                 result = flush_buffer(STp, 0);
1427                         else if (STps->eof == ST_FM_HIT) {
1428                                 result = cross_eof(STp, 0);
1429                                 if (result) {
1430                                         if (STps->drv_file >= 0)
1431                                                 STps->drv_file++;
1432                                         STps->drv_block = 0;
1433                                         STps->eof = ST_FM;
1434                                 } else
1435                                         STps->eof = ST_NOEOF;
1436                         }
1437                 } else if ((STps->eof == ST_NOEOF &&
1438                             !(result = cross_eof(STp, 1))) ||
1439                            STps->eof == ST_FM_HIT) {
1440                         if (STps->drv_file >= 0)
1441                                 STps->drv_file++;
1442                         STps->drv_block = 0;
1443                         STps->eof = ST_FM;
1444                 }
1445         }
1446
1447       out:
1448         if (STp->rew_at_close) {
1449                 result2 = st_int_ioctl(STp, MTREW, 1);
1450                 if (result == 0)
1451                         result = result2;
1452         }
1453         return result;
1454 }
1455
1456
1457 /* Close the device and release it. BKL is not needed: this is the only thread
1458    accessing this tape. */
1459 static int st_release(struct inode *inode, struct file *filp)
1460 {
1461         struct scsi_tape *STp = filp->private_data;
1462
1463         if (STp->door_locked == ST_LOCKED_AUTO)
1464                 do_door_lock(STp, 0);
1465
1466         normalize_buffer(STp->buffer);
1467         spin_lock(&st_use_lock);
1468         STp->in_use = 0;
1469         spin_unlock(&st_use_lock);
1470         scsi_autopm_put_device(STp->device);
1471         scsi_tape_put(STp);
1472
1473         return 0;
1474 }
1475
1476 /* The checks common to both reading and writing */
1477 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1478 {
1479         ssize_t retval = 0;
1480
1481         /*
1482          * If we are in the middle of error recovery, don't let anyone
1483          * else try and use this device.  Also, if error recovery fails, it
1484          * may try and take the device offline, in which case all further
1485          * access to the device is prohibited.
1486          */
1487         if (!scsi_block_when_processing_errors(STp->device)) {
1488                 retval = (-ENXIO);
1489                 goto out;
1490         }
1491
1492         if (STp->ready != ST_READY) {
1493                 if (STp->ready == ST_NO_TAPE)
1494                         retval = (-ENOMEDIUM);
1495                 else
1496                         retval = (-EIO);
1497                 goto out;
1498         }
1499
1500         if (! STp->modes[STp->current_mode].defined) {
1501                 retval = (-ENXIO);
1502                 goto out;
1503         }
1504
1505
1506         /*
1507          * If there was a bus reset, block further access
1508          * to this device.
1509          */
1510         if (STp->pos_unknown) {
1511                 retval = (-EIO);
1512                 goto out;
1513         }
1514
1515         if (count == 0)
1516                 goto out;
1517
1518         DEB(
1519         if (!STp->in_use) {
1520                 st_printk(ST_DEB_MSG, STp,
1521                           "Incorrect device.\n");
1522                 retval = (-EIO);
1523                 goto out;
1524         } ) /* end DEB */
1525
1526         if (STp->can_partitions &&
1527             (retval = switch_partition(STp)) < 0)
1528                 goto out;
1529
1530         if (STp->block_size == 0 && STp->max_block > 0 &&
1531             (count < STp->min_block || count > STp->max_block)) {
1532                 retval = (-EINVAL);
1533                 goto out;
1534         }
1535
1536         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1537             !do_door_lock(STp, 1))
1538                 STp->door_locked = ST_LOCKED_AUTO;
1539
1540  out:
1541         return retval;
1542 }
1543
1544
1545 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1546                            size_t count, int is_read)
1547 {
1548         int i, bufsize, retval = 0;
1549         struct st_buffer *STbp = STp->buffer;
1550
1551         if (is_read)
1552                 i = STp->try_dio_now && try_rdio;
1553         else
1554                 i = STp->try_dio_now && try_wdio;
1555
1556         if (i && ((unsigned long)buf & queue_dma_alignment(
1557                                         STp->device->request_queue)) == 0) {
1558                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1559                                        count, (is_read ? READ : WRITE));
1560                 if (i > 0) {
1561                         STbp->do_dio = i;
1562                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1563                 }
1564                 else
1565                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1566                 STbp->sg_segs = STbp->do_dio;
1567                 DEB(
1568                      if (STbp->do_dio) {
1569                         STp->nbr_dio++;
1570                         STp->nbr_pages += STbp->do_dio;
1571                      }
1572                 )
1573         } else
1574                 STbp->do_dio = 0;
1575         DEB( STp->nbr_requests++; )
1576
1577         if (!STbp->do_dio) {
1578                 if (STp->block_size)
1579                         bufsize = STp->block_size > st_fixed_buffer_size ?
1580                                 STp->block_size : st_fixed_buffer_size;
1581                 else {
1582                         bufsize = count;
1583                         /* Make sure that data from previous user is not leaked even if
1584                            HBA does not return correct residual */
1585                         if (is_read && STp->sili && !STbp->cleared)
1586                                 clear_buffer(STbp);
1587                 }
1588
1589                 if (bufsize > STbp->buffer_size &&
1590                     !enlarge_buffer(STbp, bufsize)) {
1591                         st_printk(KERN_WARNING, STp,
1592                                   "Can't allocate %d byte tape buffer.\n",
1593                                   bufsize);
1594                         retval = (-EOVERFLOW);
1595                         goto out;
1596                 }
1597                 if (STp->block_size)
1598                         STbp->buffer_blocks = bufsize / STp->block_size;
1599         }
1600
1601  out:
1602         return retval;
1603 }
1604
1605
1606 /* Can be called more than once after each setup_buffer() */
1607 static void release_buffering(struct scsi_tape *STp, int is_read)
1608 {
1609         struct st_buffer *STbp;
1610
1611         STbp = STp->buffer;
1612         if (STbp->do_dio) {
1613                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1614                 STbp->do_dio = 0;
1615                 STbp->sg_segs = 0;
1616         }
1617 }
1618
1619
1620 /* Write command */
1621 static ssize_t
1622 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1623 {
1624         ssize_t total;
1625         ssize_t i, do_count, blks, transfer;
1626         ssize_t retval;
1627         int undone, retry_eot = 0, scode;
1628         int async_write;
1629         unsigned char cmd[MAX_COMMAND_SIZE];
1630         const char __user *b_point;
1631         struct st_request *SRpnt = NULL;
1632         struct scsi_tape *STp = filp->private_data;
1633         struct st_modedef *STm;
1634         struct st_partstat *STps;
1635         struct st_buffer *STbp;
1636
1637         if (mutex_lock_interruptible(&STp->lock))
1638                 return -ERESTARTSYS;
1639
1640         retval = rw_checks(STp, filp, count);
1641         if (retval || count == 0)
1642                 goto out;
1643
1644         /* Write must be integral number of blocks */
1645         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1646                 st_printk(KERN_WARNING, STp,
1647                           "Write not multiple of tape block size.\n");
1648                 retval = (-EINVAL);
1649                 goto out;
1650         }
1651
1652         STm = &(STp->modes[STp->current_mode]);
1653         STps = &(STp->ps[STp->partition]);
1654
1655         if (STp->write_prot) {
1656                 retval = (-EACCES);
1657                 goto out;
1658         }
1659
1660
1661         if (STps->rw == ST_READING) {
1662                 retval = flush_buffer(STp, 0);
1663                 if (retval)
1664                         goto out;
1665                 STps->rw = ST_WRITING;
1666         } else if (STps->rw != ST_WRITING &&
1667                    STps->drv_file == 0 && STps->drv_block == 0) {
1668                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1669                         goto out;
1670                 if (STm->default_compression != ST_DONT_TOUCH &&
1671                     !(STp->compression_changed)) {
1672                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1673                                 st_printk(KERN_WARNING, STp,
1674                                           "Can't set default compression.\n");
1675                                 if (modes_defined) {
1676                                         retval = (-EINVAL);
1677                                         goto out;
1678                                 }
1679                         }
1680                 }
1681         }
1682
1683         STbp = STp->buffer;
1684         i = write_behind_check(STp);
1685         if (i) {
1686                 if (i == -ENOSPC)
1687                         STps->eof = ST_EOM_OK;
1688                 else
1689                         STps->eof = ST_EOM_ERROR;
1690         }
1691
1692         if (STps->eof == ST_EOM_OK) {
1693                 STps->eof = ST_EOD_1;  /* allow next write */
1694                 retval = (-ENOSPC);
1695                 goto out;
1696         }
1697         else if (STps->eof == ST_EOM_ERROR) {
1698                 retval = (-EIO);
1699                 goto out;
1700         }
1701
1702         /* Check the buffer readability in cases where copy_user might catch
1703            the problems after some tape movement. */
1704         if (STp->block_size != 0 &&
1705             !STbp->do_dio &&
1706             (copy_from_user(&i, buf, 1) != 0 ||
1707              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1708                 retval = (-EFAULT);
1709                 goto out;
1710         }
1711
1712         retval = setup_buffering(STp, buf, count, 0);
1713         if (retval)
1714                 goto out;
1715
1716         total = count;
1717
1718         memset(cmd, 0, MAX_COMMAND_SIZE);
1719         cmd[0] = WRITE_6;
1720         cmd[1] = (STp->block_size != 0);
1721
1722         STps->rw = ST_WRITING;
1723
1724         b_point = buf;
1725         while (count > 0 && !retry_eot) {
1726
1727                 if (STbp->do_dio) {
1728                         do_count = count;
1729                 }
1730                 else {
1731                         if (STp->block_size == 0)
1732                                 do_count = count;
1733                         else {
1734                                 do_count = STbp->buffer_blocks * STp->block_size -
1735                                         STbp->buffer_bytes;
1736                                 if (do_count > count)
1737                                         do_count = count;
1738                         }
1739
1740                         i = append_to_buffer(b_point, STbp, do_count);
1741                         if (i) {
1742                                 retval = i;
1743                                 goto out;
1744                         }
1745                 }
1746                 count -= do_count;
1747                 b_point += do_count;
1748
1749                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1750                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1751
1752                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1753                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1754                     STbp->buffer_bytes < STbp->buffer_size) {
1755                         STp->dirty = 1;
1756                         /* Don't write a buffer that is not full enough. */
1757                         if (!async_write && count == 0)
1758                                 break;
1759                 }
1760
1761         retry_write:
1762                 if (STp->block_size == 0)
1763                         blks = transfer = do_count;
1764                 else {
1765                         if (!STbp->do_dio)
1766                                 blks = STbp->buffer_bytes;
1767                         else
1768                                 blks = do_count;
1769                         blks /= STp->block_size;
1770                         transfer = blks * STp->block_size;
1771                 }
1772                 cmd[2] = blks >> 16;
1773                 cmd[3] = blks >> 8;
1774                 cmd[4] = blks;
1775
1776                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1777                                    STp->device->request_queue->rq_timeout,
1778                                    MAX_WRITE_RETRIES, !async_write);
1779                 if (!SRpnt) {
1780                         retval = STbp->syscall_result;
1781                         goto out;
1782                 }
1783                 if (async_write && !STbp->syscall_result) {
1784                         STbp->writing = transfer;
1785                         STp->dirty = !(STbp->writing ==
1786                                        STbp->buffer_bytes);
1787                         SRpnt = NULL;  /* Prevent releasing this request! */
1788                         DEB( STp->write_pending = 1; )
1789                         break;
1790                 }
1791
1792                 if (STbp->syscall_result != 0) {
1793                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1794
1795                         DEBC_printk(STp, "Error on write:\n");
1796                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1797                                 scode = cmdstatp->sense_hdr.sense_key;
1798                                 if (cmdstatp->remainder_valid)
1799                                         undone = (int)cmdstatp->uremainder64;
1800                                 else if (STp->block_size == 0 &&
1801                                          scode == VOLUME_OVERFLOW)
1802                                         undone = transfer;
1803                                 else
1804                                         undone = 0;
1805                                 if (STp->block_size != 0)
1806                                         undone *= STp->block_size;
1807                                 if (undone <= do_count) {
1808                                         /* Only data from this write is not written */
1809                                         count += undone;
1810                                         b_point -= undone;
1811                                         do_count -= undone;
1812                                         if (STp->block_size)
1813                                                 blks = (transfer - undone) / STp->block_size;
1814                                         STps->eof = ST_EOM_OK;
1815                                         /* Continue in fixed block mode if all written
1816                                            in this request but still something left to write
1817                                            (retval left to zero)
1818                                         */
1819                                         if (STp->block_size == 0 ||
1820                                             undone > 0 || count == 0)
1821                                                 retval = (-ENOSPC); /* EOM within current request */
1822                                         DEBC_printk(STp, "EOM with %d "
1823                                                     "bytes unwritten.\n",
1824                                                     (int)count);
1825                                 } else {
1826                                         /* EOT within data buffered earlier (possible only
1827                                            in fixed block mode without direct i/o) */
1828                                         if (!retry_eot && !cmdstatp->deferred &&
1829                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1830                                                 move_buffer_data(STp->buffer, transfer - undone);
1831                                                 retry_eot = 1;
1832                                                 if (STps->drv_block >= 0) {
1833                                                         STps->drv_block += (transfer - undone) /
1834                                                                 STp->block_size;
1835                                                 }
1836                                                 STps->eof = ST_EOM_OK;
1837                                                 DEBC_printk(STp, "Retry "
1838                                                             "write of %d "
1839                                                             "bytes at EOM.\n",
1840                                                             STp->buffer->buffer_bytes);
1841                                                 goto retry_write;
1842                                         }
1843                                         else {
1844                                                 /* Either error within data buffered by driver or
1845                                                    failed retry */
1846                                                 count -= do_count;
1847                                                 blks = do_count = 0;
1848                                                 STps->eof = ST_EOM_ERROR;
1849                                                 STps->drv_block = (-1); /* Too cautious? */
1850                                                 retval = (-EIO);        /* EOM for old data */
1851                                                 DEBC_printk(STp, "EOM with "
1852                                                             "lost data.\n");
1853                                         }
1854                                 }
1855                         } else {
1856                                 count += do_count;
1857                                 STps->drv_block = (-1);         /* Too cautious? */
1858                                 retval = STbp->syscall_result;
1859                         }
1860
1861                 }
1862
1863                 if (STps->drv_block >= 0) {
1864                         if (STp->block_size == 0)
1865                                 STps->drv_block += (do_count > 0);
1866                         else
1867                                 STps->drv_block += blks;
1868                 }
1869
1870                 STbp->buffer_bytes = 0;
1871                 STp->dirty = 0;
1872
1873                 if (retval || retry_eot) {
1874                         if (count < total)
1875                                 retval = total - count;
1876                         goto out;
1877                 }
1878         }
1879
1880         if (STps->eof == ST_EOD_1)
1881                 STps->eof = ST_EOM_OK;
1882         else if (STps->eof != ST_EOM_OK)
1883                 STps->eof = ST_NOEOF;
1884         retval = total - count;
1885
1886  out:
1887         if (SRpnt != NULL)
1888                 st_release_request(SRpnt);
1889         release_buffering(STp, 0);
1890         mutex_unlock(&STp->lock);
1891
1892         return retval;
1893 }
1894 \f
1895 /* Read data from the tape. Returns zero in the normal case, one if the
1896    eof status has changed, and the negative error code in case of a
1897    fatal error. Otherwise updates the buffer and the eof state.
1898
1899    Does release user buffer mapping if it is set.
1900 */
1901 static long read_tape(struct scsi_tape *STp, long count,
1902                       struct st_request ** aSRpnt)
1903 {
1904         int transfer, blks, bytes;
1905         unsigned char cmd[MAX_COMMAND_SIZE];
1906         struct st_request *SRpnt;
1907         struct st_modedef *STm;
1908         struct st_partstat *STps;
1909         struct st_buffer *STbp;
1910         int retval = 0;
1911
1912         if (count == 0)
1913                 return 0;
1914
1915         STm = &(STp->modes[STp->current_mode]);
1916         STps = &(STp->ps[STp->partition]);
1917         if (STps->eof == ST_FM_HIT)
1918                 return 1;
1919         STbp = STp->buffer;
1920
1921         if (STp->block_size == 0)
1922                 blks = bytes = count;
1923         else {
1924                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1925                         blks = (STp->buffer)->buffer_blocks;
1926                         bytes = blks * STp->block_size;
1927                 } else {
1928                         bytes = count;
1929                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1930                                 bytes = (STp->buffer)->buffer_size;
1931                         blks = bytes / STp->block_size;
1932                         bytes = blks * STp->block_size;
1933                 }
1934         }
1935
1936         memset(cmd, 0, MAX_COMMAND_SIZE);
1937         cmd[0] = READ_6;
1938         cmd[1] = (STp->block_size != 0);
1939         if (!cmd[1] && STp->sili)
1940                 cmd[1] |= 2;
1941         cmd[2] = blks >> 16;
1942         cmd[3] = blks >> 8;
1943         cmd[4] = blks;
1944
1945         SRpnt = *aSRpnt;
1946         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1947                            STp->device->request_queue->rq_timeout,
1948                            MAX_RETRIES, 1);
1949         release_buffering(STp, 1);
1950         *aSRpnt = SRpnt;
1951         if (!SRpnt)
1952                 return STbp->syscall_result;
1953
1954         STbp->read_pointer = 0;
1955         STps->at_sm = 0;
1956
1957         /* Something to check */
1958         if (STbp->syscall_result) {
1959                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1960
1961                 retval = 1;
1962                 DEBC_printk(STp,
1963                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1964                             SRpnt->sense[0], SRpnt->sense[1],
1965                             SRpnt->sense[2], SRpnt->sense[3],
1966                             SRpnt->sense[4], SRpnt->sense[5],
1967                             SRpnt->sense[6], SRpnt->sense[7]);
1968                 if (cmdstatp->have_sense) {
1969
1970                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1971                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1972
1973                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1974                                 /* Compute the residual count */
1975                                 if (cmdstatp->remainder_valid)
1976                                         transfer = (int)cmdstatp->uremainder64;
1977                                 else
1978                                         transfer = 0;
1979                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1980                                         if (STp->block_size == 0)
1981                                                 transfer = bytes;
1982                                         /* Some drives set ILI with MEDIUM ERROR */
1983                                         cmdstatp->flags &= ~SENSE_ILI;
1984                                 }
1985
1986                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1987                                         if (STp->block_size == 0 &&
1988                                             transfer < 0) {
1989                                                 st_printk(KERN_NOTICE, STp,
1990                                                           "Failed to read %d "
1991                                                           "byte block with %d "
1992                                                           "byte transfer.\n",
1993                                                           bytes - transfer,
1994                                                           bytes);
1995                                                 if (STps->drv_block >= 0)
1996                                                         STps->drv_block += 1;
1997                                                 STbp->buffer_bytes = 0;
1998                                                 return (-ENOMEM);
1999                                         } else if (STp->block_size == 0) {
2000                                                 STbp->buffer_bytes = bytes - transfer;
2001                                         } else {
2002                                                 st_release_request(SRpnt);
2003                                                 SRpnt = *aSRpnt = NULL;
2004                                                 if (transfer == blks) { /* We did not get anything, error */
2005                                                         st_printk(KERN_NOTICE, STp,
2006                                                                   "Incorrect "
2007                                                                   "block size.\n");
2008                                                         if (STps->drv_block >= 0)
2009                                                                 STps->drv_block += blks - transfer + 1;
2010                                                         st_int_ioctl(STp, MTBSR, 1);
2011                                                         return (-EIO);
2012                                                 }
2013                                                 /* We have some data, deliver it */
2014                                                 STbp->buffer_bytes = (blks - transfer) *
2015                                                     STp->block_size;
2016                                                 DEBC_printk(STp, "ILI but "
2017                                                             "enough data "
2018                                                             "received %ld "
2019                                                             "%d.\n", count,
2020                                                             STbp->buffer_bytes);
2021                                                 if (STps->drv_block >= 0)
2022                                                         STps->drv_block += 1;
2023                                                 if (st_int_ioctl(STp, MTBSR, 1))
2024                                                         return (-EIO);
2025                                         }
2026                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2027                                         if (STps->eof != ST_FM_HIT)
2028                                                 STps->eof = ST_FM_HIT;
2029                                         else
2030                                                 STps->eof = ST_EOD_2;
2031                                         if (STp->block_size == 0)
2032                                                 STbp->buffer_bytes = 0;
2033                                         else
2034                                                 STbp->buffer_bytes =
2035                                                     bytes - transfer * STp->block_size;
2036                                         DEBC_printk(STp, "EOF detected (%d "
2037                                                     "bytes read).\n",
2038                                                     STbp->buffer_bytes);
2039                                 } else if (cmdstatp->flags & SENSE_EOM) {
2040                                         if (STps->eof == ST_FM)
2041                                                 STps->eof = ST_EOD_1;
2042                                         else
2043                                                 STps->eof = ST_EOM_OK;
2044                                         if (STp->block_size == 0)
2045                                                 STbp->buffer_bytes = bytes - transfer;
2046                                         else
2047                                                 STbp->buffer_bytes =
2048                                                     bytes - transfer * STp->block_size;
2049
2050                                         DEBC_printk(STp, "EOM detected (%d "
2051                                                     "bytes read).\n",
2052                                                     STbp->buffer_bytes);
2053                                 }
2054                         }
2055                         /* end of EOF, EOM, ILI test */
2056                         else {  /* nonzero sense key */
2057                                 DEBC_printk(STp, "Tape error while reading.\n");
2058                                 STps->drv_block = (-1);
2059                                 if (STps->eof == ST_FM &&
2060                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2061                                         DEBC_printk(STp, "Zero returned for "
2062                                                     "first BLANK CHECK "
2063                                                     "after EOF.\n");
2064                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2065                                 } else  /* Some other extended sense code */
2066                                         retval = (-EIO);
2067                         }
2068
2069                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2070                                 STbp->buffer_bytes = 0;
2071                 }
2072                 /* End of extended sense test */
2073                 else {          /* Non-extended sense */
2074                         retval = STbp->syscall_result;
2075                 }
2076
2077         }
2078         /* End of error handling */
2079         else {                  /* Read successful */
2080                 STbp->buffer_bytes = bytes;
2081                 if (STp->sili) /* In fixed block mode residual is always zero here */
2082                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2083         }
2084
2085         if (STps->drv_block >= 0) {
2086                 if (STp->block_size == 0)
2087                         STps->drv_block++;
2088                 else
2089                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2090         }
2091         return retval;
2092 }
2093 \f
2094
2095 /* Read command */
2096 static ssize_t
2097 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2098 {
2099         ssize_t total;
2100         ssize_t retval = 0;
2101         ssize_t i, transfer;
2102         int special, do_dio = 0;
2103         struct st_request *SRpnt = NULL;
2104         struct scsi_tape *STp = filp->private_data;
2105         struct st_modedef *STm;
2106         struct st_partstat *STps;
2107         struct st_buffer *STbp = STp->buffer;
2108
2109         if (mutex_lock_interruptible(&STp->lock))
2110                 return -ERESTARTSYS;
2111
2112         retval = rw_checks(STp, filp, count);
2113         if (retval || count == 0)
2114                 goto out;
2115
2116         STm = &(STp->modes[STp->current_mode]);
2117         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2118                 if (!STm->do_read_ahead) {
2119                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2120                         goto out;
2121                 }
2122                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2123         }
2124
2125         STps = &(STp->ps[STp->partition]);
2126         if (STps->rw == ST_WRITING) {
2127                 retval = flush_buffer(STp, 0);
2128                 if (retval)
2129                         goto out;
2130                 STps->rw = ST_READING;
2131         }
2132         DEB(
2133         if (debugging && STps->eof != ST_NOEOF)
2134                 st_printk(ST_DEB_MSG, STp,
2135                           "EOF/EOM flag up (%d). Bytes %d\n",
2136                           STps->eof, STbp->buffer_bytes);
2137         ) /* end DEB */
2138
2139         retval = setup_buffering(STp, buf, count, 1);
2140         if (retval)
2141                 goto out;
2142         do_dio = STbp->do_dio;
2143
2144         if (STbp->buffer_bytes == 0 &&
2145             STps->eof >= ST_EOD_1) {
2146                 if (STps->eof < ST_EOD) {
2147                         STps->eof += 1;
2148                         retval = 0;
2149                         goto out;
2150                 }
2151                 retval = (-EIO);        /* EOM or Blank Check */
2152                 goto out;
2153         }
2154
2155         if (do_dio) {
2156                 /* Check the buffer writability before any tape movement. Don't alter
2157                    buffer data. */
2158                 if (copy_from_user(&i, buf, 1) != 0 ||
2159                     copy_to_user(buf, &i, 1) != 0 ||
2160                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2161                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2162                         retval = (-EFAULT);
2163                         goto out;
2164                 }
2165         }
2166
2167         STps->rw = ST_READING;
2168
2169
2170         /* Loop until enough data in buffer or a special condition found */
2171         for (total = 0, special = 0; total < count && !special;) {
2172
2173                 /* Get new data if the buffer is empty */
2174                 if (STbp->buffer_bytes == 0) {
2175                         special = read_tape(STp, count - total, &SRpnt);
2176                         if (special < 0) {      /* No need to continue read */
2177                                 retval = special;
2178                                 goto out;
2179                         }
2180                 }
2181
2182                 /* Move the data from driver buffer to user buffer */
2183                 if (STbp->buffer_bytes > 0) {
2184                         DEB(
2185                         if (debugging && STps->eof != ST_NOEOF)
2186                                 st_printk(ST_DEB_MSG, STp,
2187                                           "EOF up (%d). Left %d, needed %d.\n",
2188                                           STps->eof, STbp->buffer_bytes,
2189                                           (int)(count - total));
2190                         ) /* end DEB */
2191                         transfer = STbp->buffer_bytes < count - total ?
2192                             STbp->buffer_bytes : count - total;
2193                         if (!do_dio) {
2194                                 i = from_buffer(STbp, buf, transfer);
2195                                 if (i) {
2196                                         retval = i;
2197                                         goto out;
2198                                 }
2199                         }
2200                         buf += transfer;
2201                         total += transfer;
2202                 }
2203
2204                 if (STp->block_size == 0)
2205                         break;  /* Read only one variable length block */
2206
2207         }                       /* for (total = 0, special = 0;
2208                                    total < count && !special; ) */
2209
2210         /* Change the eof state if no data from tape or buffer */
2211         if (total == 0) {
2212                 if (STps->eof == ST_FM_HIT) {
2213                         STps->eof = ST_FM;
2214                         STps->drv_block = 0;
2215                         if (STps->drv_file >= 0)
2216                                 STps->drv_file++;
2217                 } else if (STps->eof == ST_EOD_1) {
2218                         STps->eof = ST_EOD_2;
2219                         STps->drv_block = 0;
2220                         if (STps->drv_file >= 0)
2221                                 STps->drv_file++;
2222                 } else if (STps->eof == ST_EOD_2)
2223                         STps->eof = ST_EOD;
2224         } else if (STps->eof == ST_FM)
2225                 STps->eof = ST_NOEOF;
2226         retval = total;
2227
2228  out:
2229         if (SRpnt != NULL) {
2230                 st_release_request(SRpnt);
2231                 SRpnt = NULL;
2232         }
2233         if (do_dio) {
2234                 release_buffering(STp, 1);
2235                 STbp->buffer_bytes = 0;
2236         }
2237         mutex_unlock(&STp->lock);
2238
2239         return retval;
2240 }
2241 \f
2242
2243
2244 DEB(
2245 /* Set the driver options */
2246 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2247 {
2248         if (debugging) {
2249                 st_printk(KERN_INFO, STp,
2250                           "Mode %d options: buffer writes: %d, "
2251                           "async writes: %d, read ahead: %d\n",
2252                           STp->current_mode, STm->do_buffer_writes,
2253                           STm->do_async_writes, STm->do_read_ahead);
2254                 st_printk(KERN_INFO, STp,
2255                           "    can bsr: %d, two FMs: %d, "
2256                           "fast mteom: %d, auto lock: %d,\n",
2257                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2258                           STp->do_auto_lock);
2259                 st_printk(KERN_INFO, STp,
2260                           "    defs for wr: %d, no block limits: %d, "
2261                           "partitions: %d, s2 log: %d\n",
2262                           STm->defaults_for_writes, STp->omit_blklims,
2263                           STp->can_partitions, STp->scsi2_logical);
2264                 st_printk(KERN_INFO, STp,
2265                           "    sysv: %d nowait: %d sili: %d "
2266                           "nowait_filemark: %d\n",
2267                           STm->sysv, STp->immediate, STp->sili,
2268                           STp->immediate_filemark);
2269                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2270         }
2271 }
2272         )
2273
2274
2275 static int st_set_options(struct scsi_tape *STp, long options)
2276 {
2277         int value;
2278         long code;
2279         struct st_modedef *STm;
2280         struct cdev *cd0, *cd1;
2281         struct device *d0, *d1;
2282
2283         STm = &(STp->modes[STp->current_mode]);
2284         if (!STm->defined) {
2285                 cd0 = STm->cdevs[0];
2286                 cd1 = STm->cdevs[1];
2287                 d0  = STm->devs[0];
2288                 d1  = STm->devs[1];
2289                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2290                 STm->cdevs[0] = cd0;
2291                 STm->cdevs[1] = cd1;
2292                 STm->devs[0]  = d0;
2293                 STm->devs[1]  = d1;
2294                 modes_defined = 1;
2295                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2296                             STp->current_mode);
2297         }
2298
2299         code = options & MT_ST_OPTIONS;
2300         if (code == MT_ST_BOOLEANS) {
2301                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2302                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2303                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2304                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2305                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2306                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2307                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2308                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2309                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2310                 if ((STp->device)->scsi_level >= SCSI_2)
2311                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2312                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2313                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2314                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2315                 STm->sysv = (options & MT_ST_SYSV) != 0;
2316                 STp->sili = (options & MT_ST_SILI) != 0;
2317                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2318                      st_log_options(STp, STm); )
2319         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2320                 value = (code == MT_ST_SETBOOLEANS);
2321                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2322                         STm->do_buffer_writes = value;
2323                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2324                         STm->do_async_writes = value;
2325                 if ((options & MT_ST_DEF_WRITES) != 0)
2326                         STm->defaults_for_writes = value;
2327                 if ((options & MT_ST_READ_AHEAD) != 0)
2328                         STm->do_read_ahead = value;
2329                 if ((options & MT_ST_TWO_FM) != 0)
2330                         STp->two_fm = value;
2331                 if ((options & MT_ST_FAST_MTEOM) != 0)
2332                         STp->fast_mteom = value;
2333                 if ((options & MT_ST_AUTO_LOCK) != 0)
2334                         STp->do_auto_lock = value;
2335                 if ((options & MT_ST_CAN_BSR) != 0)
2336                         STp->can_bsr = value;
2337                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2338                         STp->omit_blklims = value;
2339                 if ((STp->device)->scsi_level >= SCSI_2 &&
2340                     (options & MT_ST_CAN_PARTITIONS) != 0)
2341                         STp->can_partitions = value;
2342                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2343                         STp->scsi2_logical = value;
2344                 if ((options & MT_ST_NOWAIT) != 0)
2345                         STp->immediate = value;
2346                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2347                         STp->immediate_filemark = value;
2348                 if ((options & MT_ST_SYSV) != 0)
2349                         STm->sysv = value;
2350                 if ((options & MT_ST_SILI) != 0)
2351                         STp->sili = value;
2352                 DEB(
2353                 if ((options & MT_ST_DEBUGGING) != 0)
2354                         debugging = value;
2355                         st_log_options(STp, STm); )
2356         } else if (code == MT_ST_WRITE_THRESHOLD) {
2357                 /* Retained for compatibility */
2358         } else if (code == MT_ST_DEF_BLKSIZE) {
2359                 value = (options & ~MT_ST_OPTIONS);
2360                 if (value == ~MT_ST_OPTIONS) {
2361                         STm->default_blksize = (-1);
2362                         DEBC_printk(STp, "Default block size disabled.\n");
2363                 } else {
2364                         STm->default_blksize = value;
2365                         DEBC_printk(STp,"Default block size set to "
2366                                     "%d bytes.\n", STm->default_blksize);
2367                         if (STp->ready == ST_READY) {
2368                                 STp->blksize_changed = 0;
2369                                 set_mode_densblk(STp, STm);
2370                         }
2371                 }
2372         } else if (code == MT_ST_TIMEOUTS) {
2373                 value = (options & ~MT_ST_OPTIONS);
2374                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2375                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2376                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2377                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2378                 } else {
2379                         blk_queue_rq_timeout(STp->device->request_queue,
2380                                              value * HZ);
2381                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2382                                     value);
2383                 }
2384         } else if (code == MT_ST_SET_CLN) {
2385                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2386                 if (value != 0 &&
2387                         (value < EXTENDED_SENSE_START ||
2388                                 value >= SCSI_SENSE_BUFFERSIZE))
2389                         return (-EINVAL);
2390                 STp->cln_mode = value;
2391                 STp->cln_sense_mask = (options >> 8) & 0xff;
2392                 STp->cln_sense_value = (options >> 16) & 0xff;
2393                 st_printk(KERN_INFO, STp,
2394                           "Cleaning request mode %d, mask %02x, value %02x\n",
2395                           value, STp->cln_sense_mask, STp->cln_sense_value);
2396         } else if (code == MT_ST_DEF_OPTIONS) {
2397                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2398                 value = (options & MT_ST_CLEAR_DEFAULT);
2399                 if (code == MT_ST_DEF_DENSITY) {
2400                         if (value == MT_ST_CLEAR_DEFAULT) {
2401                                 STm->default_density = (-1);
2402                                 DEBC_printk(STp,
2403                                             "Density default disabled.\n");
2404                         } else {
2405                                 STm->default_density = value & 0xff;
2406                                 DEBC_printk(STp, "Density default set to %x\n",
2407                                             STm->default_density);
2408                                 if (STp->ready == ST_READY) {
2409                                         STp->density_changed = 0;
2410                                         set_mode_densblk(STp, STm);
2411                                 }
2412                         }
2413                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2414                         if (value == MT_ST_CLEAR_DEFAULT) {
2415                                 STp->default_drvbuffer = 0xff;
2416                                 DEBC_printk(STp,
2417                                             "Drive buffer default disabled.\n");
2418                         } else {
2419                                 STp->default_drvbuffer = value & 7;
2420                                 DEBC_printk(STp,
2421                                             "Drive buffer default set to %x\n",
2422                                             STp->default_drvbuffer);
2423                                 if (STp->ready == ST_READY)
2424                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2425                         }
2426                 } else if (code == MT_ST_DEF_COMPRESSION) {
2427                         if (value == MT_ST_CLEAR_DEFAULT) {
2428                                 STm->default_compression = ST_DONT_TOUCH;
2429                                 DEBC_printk(STp,
2430                                             "Compression default disabled.\n");
2431                         } else {
2432                                 if ((value & 0xff00) != 0) {
2433                                         STp->c_algo = (value & 0xff00) >> 8;
2434                                         DEBC_printk(STp, "Compression "
2435                                                     "algorithm set to 0x%x.\n",
2436                                                     STp->c_algo);
2437                                 }
2438                                 if ((value & 0xff) != 0xff) {
2439                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2440                                         DEBC_printk(STp, "Compression default "
2441                                                     "set to %x\n",
2442                                                     (value & 1));
2443                                         if (STp->ready == ST_READY) {
2444                                                 STp->compression_changed = 0;
2445                                                 st_compression(STp, (STm->default_compression == ST_YES));
2446                                         }
2447                                 }
2448                         }
2449                 }
2450         } else
2451                 return (-EIO);
2452
2453         return 0;
2454 }
2455 \f
2456 #define MODE_HEADER_LENGTH  4
2457
2458 /* Mode header and page byte offsets */
2459 #define MH_OFF_DATA_LENGTH     0
2460 #define MH_OFF_MEDIUM_TYPE     1
2461 #define MH_OFF_DEV_SPECIFIC    2
2462 #define MH_OFF_BDESCS_LENGTH   3
2463 #define MP_OFF_PAGE_NBR        0
2464 #define MP_OFF_PAGE_LENGTH     1
2465
2466 /* Mode header and page bit masks */
2467 #define MH_BIT_WP              0x80
2468 #define MP_MSK_PAGE_NBR        0x3f
2469
2470 /* Don't return block descriptors */
2471 #define MODE_SENSE_OMIT_BDESCS 0x08
2472
2473 #define MODE_SELECT_PAGE_FORMAT 0x10
2474
2475 /* Read a mode page into the tape buffer. The block descriptors are included
2476    if incl_block_descs is true. The page control is ored to the page number
2477    parameter, if necessary. */
2478 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2479 {
2480         unsigned char cmd[MAX_COMMAND_SIZE];
2481         struct st_request *SRpnt;
2482
2483         memset(cmd, 0, MAX_COMMAND_SIZE);
2484         cmd[0] = MODE_SENSE;
2485         if (omit_block_descs)
2486                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2487         cmd[2] = page;
2488         cmd[4] = 255;
2489
2490         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2491                            STp->device->request_queue->rq_timeout, 0, 1);
2492         if (SRpnt == NULL)
2493                 return (STp->buffer)->syscall_result;
2494
2495         st_release_request(SRpnt);
2496
2497         return STp->buffer->syscall_result;
2498 }
2499
2500
2501 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2502    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2503 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2504 {
2505         int pgo;
2506         unsigned char cmd[MAX_COMMAND_SIZE];
2507         struct st_request *SRpnt;
2508         int timeout;
2509
2510         memset(cmd, 0, MAX_COMMAND_SIZE);
2511         cmd[0] = MODE_SELECT;
2512         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2513         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2514         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2515
2516         /* Clear reserved fields */
2517         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2518         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2519         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2520         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2521
2522         timeout = slow ?
2523                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2524         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2525                            timeout, 0, 1);
2526         if (SRpnt == NULL)
2527                 return (STp->buffer)->syscall_result;
2528
2529         st_release_request(SRpnt);
2530
2531         return STp->buffer->syscall_result;
2532 }
2533
2534
2535 #define COMPRESSION_PAGE        0x0f
2536 #define COMPRESSION_PAGE_LENGTH 16
2537
2538 #define CP_OFF_DCE_DCC          2
2539 #define CP_OFF_C_ALGO           7
2540
2541 #define DCE_MASK  0x80
2542 #define DCC_MASK  0x40
2543 #define RED_MASK  0x60
2544
2545
2546 /* Control the compression with mode page 15. Algorithm not changed if zero.
2547
2548    The block descriptors are read and written because Sony SDT-7000 does not
2549    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2550    Including block descriptors should not cause any harm to other drives. */
2551
2552 static int st_compression(struct scsi_tape * STp, int state)
2553 {
2554         int retval;
2555         int mpoffs;  /* Offset to mode page start */
2556         unsigned char *b_data = (STp->buffer)->b_data;
2557
2558         if (STp->ready != ST_READY)
2559                 return (-EIO);
2560
2561         /* Read the current page contents */
2562         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2563         if (retval) {
2564                 DEBC_printk(STp, "Compression mode page not supported.\n");
2565                 return (-EIO);
2566         }
2567
2568         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2569         DEBC_printk(STp, "Compression state is %d.\n",
2570                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2571
2572         /* Check if compression can be changed */
2573         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2574                 DEBC_printk(STp, "Compression not supported.\n");
2575                 return (-EIO);
2576         }
2577
2578         /* Do the change */
2579         if (state) {
2580                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2581                 if (STp->c_algo != 0)
2582                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2583         }
2584         else {
2585                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2586                 if (STp->c_algo != 0)
2587                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2588         }
2589
2590         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2591         if (retval) {
2592                 DEBC_printk(STp, "Compression change failed.\n");
2593                 return (-EIO);
2594         }
2595         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2596
2597         STp->compression_changed = 1;
2598         return 0;
2599 }
2600
2601
2602 /* Process the load and unload commands (does unload if the load code is zero) */
2603 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2604 {
2605         int retval = (-EIO), timeout;
2606         unsigned char cmd[MAX_COMMAND_SIZE];
2607         struct st_partstat *STps;
2608         struct st_request *SRpnt;
2609
2610         if (STp->ready != ST_READY && !load_code) {
2611                 if (STp->ready == ST_NO_TAPE)
2612                         return (-ENOMEDIUM);
2613                 else
2614                         return (-EIO);
2615         }
2616
2617         memset(cmd, 0, MAX_COMMAND_SIZE);
2618         cmd[0] = START_STOP;
2619         if (load_code)
2620                 cmd[4] |= 1;
2621         /*
2622          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2623          */
2624         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2625             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2626                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2627                             (cmd[4]) ? "" : "un",
2628                             load_code - MT_ST_HPLOADER_OFFSET);
2629                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2630         }
2631         if (STp->immediate) {
2632                 cmd[1] = 1;     /* Don't wait for completion */
2633                 timeout = STp->device->request_queue->rq_timeout;
2634         }
2635         else
2636                 timeout = STp->long_timeout;
2637
2638         DEBC(
2639                 if (!load_code)
2640                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2641                 else
2642                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2643                 );
2644
2645         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2646                            timeout, MAX_RETRIES, 1);
2647         if (!SRpnt)
2648                 return (STp->buffer)->syscall_result;
2649
2650         retval = (STp->buffer)->syscall_result;
2651         st_release_request(SRpnt);
2652
2653         if (!retval) {  /* SCSI command successful */
2654
2655                 if (!load_code) {
2656                         STp->rew_at_close = 0;
2657                         STp->ready = ST_NO_TAPE;
2658                 }
2659                 else {
2660                         STp->rew_at_close = STp->autorew_dev;
2661                         retval = check_tape(STp, filp);
2662                         if (retval > 0)
2663                                 retval = 0;
2664                 }
2665         }
2666         else {
2667                 STps = &(STp->ps[STp->partition]);
2668                 STps->drv_file = STps->drv_block = (-1);
2669         }
2670
2671         return retval;
2672 }
2673 \f
2674 #if DEBUG
2675 #define ST_DEB_FORWARD  0
2676 #define ST_DEB_BACKWARD 1
2677 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2678 {
2679         s32 sc;
2680
2681         if (!debugging)
2682                 return;
2683
2684         sc = sign_extend32(get_unaligned_be24(&cmd[2]), 23);
2685         if (direction)
2686                 sc = -sc;
2687         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688                   direction ? "backward" : "forward", sc, units);
2689 }
2690 #else
2691 #define ST_DEB_FORWARD  0
2692 #define ST_DEB_BACKWARD 1
2693 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694 #endif
2695
2696
2697 /* Internal ioctl function */
2698 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699 {
2700         int timeout;
2701         long ltmp;
2702         int ioctl_result;
2703         int chg_eof = 1;
2704         unsigned char cmd[MAX_COMMAND_SIZE];
2705         struct st_request *SRpnt;
2706         struct st_partstat *STps;
2707         int fileno, blkno, at_sm, undone;
2708         int datalen = 0, direction = DMA_NONE;
2709
2710         WARN_ON(STp->buffer->do_dio != 0);
2711         if (STp->ready != ST_READY) {
2712                 if (STp->ready == ST_NO_TAPE)
2713                         return (-ENOMEDIUM);
2714                 else
2715                         return (-EIO);
2716         }
2717         timeout = STp->long_timeout;
2718         STps = &(STp->ps[STp->partition]);
2719         fileno = STps->drv_file;
2720         blkno = STps->drv_block;
2721         at_sm = STps->at_sm;
2722
2723         memset(cmd, 0, MAX_COMMAND_SIZE);
2724         switch (cmd_in) {
2725         case MTFSFM:
2726                 chg_eof = 0;    /* Changed from the FSF after this */
2727                 fallthrough;
2728         case MTFSF:
2729                 cmd[0] = SPACE;
2730                 cmd[1] = 0x01;  /* Space FileMarks */
2731                 cmd[2] = (arg >> 16);
2732                 cmd[3] = (arg >> 8);
2733                 cmd[4] = arg;
2734                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735                 if (fileno >= 0)
2736                         fileno += arg;
2737                 blkno = 0;
2738                 at_sm &= (arg == 0);
2739                 break;
2740         case MTBSFM:
2741                 chg_eof = 0;    /* Changed from the FSF after this */
2742                 fallthrough;
2743         case MTBSF:
2744                 cmd[0] = SPACE;
2745                 cmd[1] = 0x01;  /* Space FileMarks */
2746                 ltmp = (-arg);
2747                 cmd[2] = (ltmp >> 16);
2748                 cmd[3] = (ltmp >> 8);
2749                 cmd[4] = ltmp;
2750                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2751                 if (fileno >= 0)
2752                         fileno -= arg;
2753                 blkno = (-1);   /* We can't know the block number */
2754                 at_sm &= (arg == 0);
2755                 break;
2756         case MTFSR:
2757                 cmd[0] = SPACE;
2758                 cmd[1] = 0x00;  /* Space Blocks */
2759                 cmd[2] = (arg >> 16);
2760                 cmd[3] = (arg >> 8);
2761                 cmd[4] = arg;
2762                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2763                 if (blkno >= 0)
2764                         blkno += arg;
2765                 at_sm &= (arg == 0);
2766                 break;
2767         case MTBSR:
2768                 cmd[0] = SPACE;
2769                 cmd[1] = 0x00;  /* Space Blocks */
2770                 ltmp = (-arg);
2771                 cmd[2] = (ltmp >> 16);
2772                 cmd[3] = (ltmp >> 8);
2773                 cmd[4] = ltmp;
2774                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2775                 if (blkno >= 0)
2776                         blkno -= arg;
2777                 at_sm &= (arg == 0);
2778                 break;
2779         case MTFSS:
2780                 cmd[0] = SPACE;
2781                 cmd[1] = 0x04;  /* Space Setmarks */
2782                 cmd[2] = (arg >> 16);
2783                 cmd[3] = (arg >> 8);
2784                 cmd[4] = arg;
2785                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2786                 if (arg != 0) {
2787                         blkno = fileno = (-1);
2788                         at_sm = 1;
2789                 }
2790                 break;
2791         case MTBSS:
2792                 cmd[0] = SPACE;
2793                 cmd[1] = 0x04;  /* Space Setmarks */
2794                 ltmp = (-arg);
2795                 cmd[2] = (ltmp >> 16);
2796                 cmd[3] = (ltmp >> 8);
2797                 cmd[4] = ltmp;
2798                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2799                 if (arg != 0) {
2800                         blkno = fileno = (-1);
2801                         at_sm = 1;
2802                 }
2803                 break;
2804         case MTWEOF:
2805         case MTWEOFI:
2806         case MTWSM:
2807                 if (STp->write_prot)
2808                         return (-EACCES);
2809                 cmd[0] = WRITE_FILEMARKS;
2810                 if (cmd_in == MTWSM)
2811                         cmd[1] = 2;
2812                 if (cmd_in == MTWEOFI ||
2813                     (cmd_in == MTWEOF && STp->immediate_filemark))
2814                         cmd[1] |= 1;
2815                 cmd[2] = (arg >> 16);
2816                 cmd[3] = (arg >> 8);
2817                 cmd[4] = arg;
2818                 timeout = STp->device->request_queue->rq_timeout;
2819                 DEBC(
2820                         if (cmd_in != MTWSM)
2821                                 st_printk(ST_DEB_MSG, STp,
2822                                           "Writing %d filemarks.\n",
2823                                           cmd[2] * 65536 +
2824                                           cmd[3] * 256 +
2825                                           cmd[4]);
2826                         else
2827                                 st_printk(ST_DEB_MSG, STp,
2828                                           "Writing %d setmarks.\n",
2829                                           cmd[2] * 65536 +
2830                                           cmd[3] * 256 +
2831                                           cmd[4]);
2832                 )
2833                 if (fileno >= 0)
2834                         fileno += arg;
2835                 blkno = 0;
2836                 at_sm = (cmd_in == MTWSM);
2837                 break;
2838         case MTREW:
2839                 cmd[0] = REZERO_UNIT;
2840                 if (STp->immediate) {
2841                         cmd[1] = 1;     /* Don't wait for completion */
2842                         timeout = STp->device->request_queue->rq_timeout;
2843                 }
2844                 DEBC_printk(STp, "Rewinding tape.\n");
2845                 fileno = blkno = at_sm = 0;
2846                 break;
2847         case MTNOP:
2848                 DEBC_printk(STp, "No op on tape.\n");
2849                 return 0;       /* Should do something ? */
2850         case MTRETEN:
2851                 cmd[0] = START_STOP;
2852                 if (STp->immediate) {
2853                         cmd[1] = 1;     /* Don't wait for completion */
2854                         timeout = STp->device->request_queue->rq_timeout;
2855                 }
2856                 cmd[4] = 3;
2857                 DEBC_printk(STp, "Retensioning tape.\n");
2858                 fileno = blkno = at_sm = 0;
2859                 break;
2860         case MTEOM:
2861                 if (!STp->fast_mteom) {
2862                         /* space to the end of tape */
2863                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2864                         fileno = STps->drv_file;
2865                         if (STps->eof >= ST_EOD_1)
2866                                 return 0;
2867                         /* The next lines would hide the number of spaced FileMarks
2868                            That's why I inserted the previous lines. I had no luck
2869                            with detecting EOM with FSF, so we go now to EOM.
2870                            Joerg Weule */
2871                 } else
2872                         fileno = (-1);
2873                 cmd[0] = SPACE;
2874                 cmd[1] = 3;
2875                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2876                 blkno = -1;
2877                 at_sm = 0;
2878                 break;
2879         case MTERASE:
2880                 if (STp->write_prot)
2881                         return (-EACCES);
2882                 cmd[0] = ERASE;
2883                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2884                 if (STp->immediate) {
2885                         cmd[1] |= 2;    /* Don't wait for completion */
2886                         timeout = STp->device->request_queue->rq_timeout;
2887                 }
2888                 else
2889                         timeout = STp->long_timeout * 8;
2890
2891                 DEBC_printk(STp, "Erasing tape.\n");
2892                 fileno = blkno = at_sm = 0;
2893                 break;
2894         case MTSETBLK:          /* Set block length */
2895         case MTSETDENSITY:      /* Set tape density */
2896         case MTSETDRVBUFFER:    /* Set drive buffering */
2897         case SET_DENS_AND_BLK:  /* Set density and block size */
2898                 chg_eof = 0;
2899                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2900                         return (-EIO);  /* Not allowed if data in buffer */
2901                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2902                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2903                     STp->max_block > 0 &&
2904                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2905                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2906                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2907                         return (-EINVAL);
2908                 }
2909                 cmd[0] = MODE_SELECT;
2910                 if ((STp->use_pf & USE_PF))
2911                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2912                 cmd[4] = datalen = 12;
2913                 direction = DMA_TO_DEVICE;
2914
2915                 memset((STp->buffer)->b_data, 0, 12);
2916                 if (cmd_in == MTSETDRVBUFFER)
2917                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2918                 else
2919                         (STp->buffer)->b_data[2] =
2920                             STp->drv_buffer << 4;
2921                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2922                 if (cmd_in == MTSETDENSITY) {
2923                         (STp->buffer)->b_data[4] = arg;
2924                         STp->density_changed = 1;       /* At least we tried ;-) */
2925                 } else if (cmd_in == SET_DENS_AND_BLK)
2926                         (STp->buffer)->b_data[4] = arg >> 24;
2927                 else
2928                         (STp->buffer)->b_data[4] = STp->density;
2929                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2930                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2931                         if (cmd_in == MTSETBLK)
2932                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2933                 } else
2934                         ltmp = STp->block_size;
2935                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2936                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2937                 (STp->buffer)->b_data[11] = ltmp;
2938                 timeout = STp->device->request_queue->rq_timeout;
2939                 DEBC(
2940                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2941                                 st_printk(ST_DEB_MSG, STp,
2942                                           "Setting block size to %d bytes.\n",
2943                                           (STp->buffer)->b_data[9] * 65536 +
2944                                           (STp->buffer)->b_data[10] * 256 +
2945                                           (STp->buffer)->b_data[11]);
2946                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2947                                 st_printk(ST_DEB_MSG, STp,
2948                                           "Setting density code to %x.\n",
2949                                           (STp->buffer)->b_data[4]);
2950                         if (cmd_in == MTSETDRVBUFFER)
2951                                 st_printk(ST_DEB_MSG, STp,
2952                                           "Setting drive buffer code to %d.\n",
2953                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2954                 )
2955                 break;
2956         default:
2957                 return (-ENOSYS);
2958         }
2959
2960         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2961                            timeout, MAX_RETRIES, 1);
2962         if (!SRpnt)
2963                 return (STp->buffer)->syscall_result;
2964
2965         ioctl_result = (STp->buffer)->syscall_result;
2966
2967         if (!ioctl_result) {    /* SCSI command successful */
2968                 st_release_request(SRpnt);
2969                 SRpnt = NULL;
2970                 STps->drv_block = blkno;
2971                 STps->drv_file = fileno;
2972                 STps->at_sm = at_sm;
2973
2974                 if (cmd_in == MTBSFM)
2975                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2976                 else if (cmd_in == MTFSFM)
2977                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2978
2979                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2980                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2981                         if (STp->block_size != 0) {
2982                                 (STp->buffer)->buffer_blocks =
2983                                     (STp->buffer)->buffer_size / STp->block_size;
2984                         }
2985                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2986                         if (cmd_in == SET_DENS_AND_BLK)
2987                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2988                 } else if (cmd_in == MTSETDRVBUFFER)
2989                         STp->drv_buffer = (arg & 7);
2990                 else if (cmd_in == MTSETDENSITY)
2991                         STp->density = arg;
2992
2993                 if (cmd_in == MTEOM)
2994                         STps->eof = ST_EOD;
2995                 else if (cmd_in == MTFSF)
2996                         STps->eof = ST_FM;
2997                 else if (chg_eof)
2998                         STps->eof = ST_NOEOF;
2999
3000                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3001                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3002         } else { /* SCSI command was not completely successful. Don't return
3003                     from this block without releasing the SCSI command block! */
3004                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3005
3006                 if (cmdstatp->flags & SENSE_EOM) {
3007                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3008                             cmd_in != MTBSR && cmd_in != MTBSS)
3009                                 STps->eof = ST_EOM_OK;
3010                         STps->drv_block = 0;
3011                 }
3012
3013                 if (cmdstatp->remainder_valid)
3014                         undone = (int)cmdstatp->uremainder64;
3015                 else
3016                         undone = 0;
3017
3018                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3019                     cmdstatp->have_sense &&
3020                     (cmdstatp->flags & SENSE_EOM)) {
3021                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3022                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3023                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3024                                 STps->eof = ST_NOEOF;
3025                         } else {  /* Writing EOF(s) failed */
3026                                 if (fileno >= 0)
3027                                         fileno -= undone;
3028                                 if (undone < arg)
3029                                         STps->eof = ST_NOEOF;
3030                         }
3031                         STps->drv_file = fileno;
3032                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3033                         if (fileno >= 0)
3034                                 STps->drv_file = fileno - undone;
3035                         else
3036                                 STps->drv_file = fileno;
3037                         STps->drv_block = -1;
3038                         STps->eof = ST_NOEOF;
3039                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3040                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3041                                 undone = (-undone);
3042                         if (STps->drv_file >= 0)
3043                                 STps->drv_file = fileno + undone;
3044                         STps->drv_block = 0;
3045                         STps->eof = ST_NOEOF;
3046                 } else if (cmd_in == MTFSR) {
3047                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3048                                 if (STps->drv_file >= 0)
3049                                         STps->drv_file++;
3050                                 STps->drv_block = 0;
3051                                 STps->eof = ST_FM;
3052                         } else {
3053                                 if (blkno >= undone)
3054                                         STps->drv_block = blkno - undone;
3055                                 else
3056                                         STps->drv_block = (-1);
3057                                 STps->eof = ST_NOEOF;
3058                         }
3059                 } else if (cmd_in == MTBSR) {
3060                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3061                                 STps->drv_file--;
3062                                 STps->drv_block = (-1);
3063                         } else {
3064                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3065                                         undone = (-undone);
3066                                 if (STps->drv_block >= 0)
3067                                         STps->drv_block = blkno + undone;
3068                         }
3069                         STps->eof = ST_NOEOF;
3070                 } else if (cmd_in == MTEOM) {
3071                         STps->drv_file = (-1);
3072                         STps->drv_block = (-1);
3073                         STps->eof = ST_EOD;
3074                 } else if (cmd_in == MTSETBLK ||
3075                            cmd_in == MTSETDENSITY ||
3076                            cmd_in == MTSETDRVBUFFER ||
3077                            cmd_in == SET_DENS_AND_BLK) {
3078                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3079                             !(STp->use_pf & PF_TESTED)) {
3080                                 /* Try the other possible state of Page Format if not
3081                                    already tried */
3082                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3083                                 st_release_request(SRpnt);
3084                                 SRpnt = NULL;
3085                                 return st_int_ioctl(STp, cmd_in, arg);
3086                         }
3087                 } else if (chg_eof)
3088                         STps->eof = ST_NOEOF;
3089
3090                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3091                         STps->eof = ST_EOD;
3092
3093                 st_release_request(SRpnt);
3094                 SRpnt = NULL;
3095         }
3096
3097         return ioctl_result;
3098 }
3099 \f
3100
3101 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3102    structure. */
3103
3104 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3105                         int logical)
3106 {
3107         int result;
3108         unsigned char scmd[MAX_COMMAND_SIZE];
3109         struct st_request *SRpnt;
3110
3111         if (STp->ready != ST_READY)
3112                 return (-EIO);
3113
3114         memset(scmd, 0, MAX_COMMAND_SIZE);
3115         if ((STp->device)->scsi_level < SCSI_2) {
3116                 scmd[0] = QFA_REQUEST_BLOCK;
3117                 scmd[4] = 3;
3118         } else {
3119                 scmd[0] = READ_POSITION;
3120                 if (!logical && !STp->scsi2_logical)
3121                         scmd[1] = 1;
3122         }
3123         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3124                            STp->device->request_queue->rq_timeout,
3125                            MAX_READY_RETRIES, 1);
3126         if (!SRpnt)
3127                 return (STp->buffer)->syscall_result;
3128
3129         if ((STp->buffer)->syscall_result != 0 ||
3130             (STp->device->scsi_level >= SCSI_2 &&
3131              ((STp->buffer)->b_data[0] & 4) != 0)) {
3132                 *block = *partition = 0;
3133                 DEBC_printk(STp, " Can't read tape position.\n");
3134                 result = (-EIO);
3135         } else {
3136                 result = 0;
3137                 if ((STp->device)->scsi_level < SCSI_2) {
3138                         *block = ((STp->buffer)->b_data[0] << 16)
3139                             + ((STp->buffer)->b_data[1] << 8)
3140                             + (STp->buffer)->b_data[2];
3141                         *partition = 0;
3142                 } else {
3143                         *block = ((STp->buffer)->b_data[4] << 24)
3144                             + ((STp->buffer)->b_data[5] << 16)
3145                             + ((STp->buffer)->b_data[6] << 8)
3146                             + (STp->buffer)->b_data[7];
3147                         *partition = (STp->buffer)->b_data[1];
3148                         if (((STp->buffer)->b_data[0] & 0x80) &&
3149                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3150                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3151                 }
3152                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3153                             *block, *partition);
3154         }
3155         st_release_request(SRpnt);
3156         SRpnt = NULL;
3157
3158         return result;
3159 }
3160
3161
3162 /* Set the tape block and partition. Negative partition means that only the
3163    block should be set in vendor specific way. */
3164 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3165                         int logical)
3166 {
3167         struct st_partstat *STps;
3168         int result, p;
3169         unsigned int blk;
3170         int timeout;
3171         unsigned char scmd[MAX_COMMAND_SIZE];
3172         struct st_request *SRpnt;
3173
3174         if (STp->ready != ST_READY)
3175                 return (-EIO);
3176         timeout = STp->long_timeout;
3177         STps = &(STp->ps[STp->partition]);
3178
3179         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3180                     block, partition);
3181         DEB(if (partition < 0)
3182                 return (-EIO); )
3183
3184         /* Update the location at the partition we are leaving */
3185         if ((!STp->can_partitions && partition != 0) ||
3186             partition >= ST_NBR_PARTITIONS)
3187                 return (-EINVAL);
3188         if (partition != STp->partition) {
3189                 if (get_location(STp, &blk, &p, 1))
3190                         STps->last_block_valid = 0;
3191                 else {
3192                         STps->last_block_valid = 1;
3193                         STps->last_block_visited = blk;
3194                         DEBC_printk(STp, "Visited block %d for "
3195                                     "partition %d saved.\n",
3196                                     blk, STp->partition);
3197                 }
3198         }
3199
3200         memset(scmd, 0, MAX_COMMAND_SIZE);
3201         if ((STp->device)->scsi_level < SCSI_2) {
3202                 scmd[0] = QFA_SEEK_BLOCK;
3203                 scmd[2] = (block >> 16);
3204                 scmd[3] = (block >> 8);
3205                 scmd[4] = block;
3206                 scmd[5] = 0;
3207         } else {
3208                 scmd[0] = SEEK_10;
3209                 scmd[3] = (block >> 24);
3210                 scmd[4] = (block >> 16);
3211                 scmd[5] = (block >> 8);
3212                 scmd[6] = block;
3213                 if (!logical && !STp->scsi2_logical)
3214                         scmd[1] = 4;
3215                 if (STp->partition != partition) {
3216                         scmd[1] |= 2;
3217                         scmd[8] = partition;
3218                         DEBC_printk(STp, "Trying to change partition "
3219                                     "from %d to %d\n", STp->partition,
3220                                     partition);
3221                 }
3222         }
3223         if (STp->immediate) {
3224                 scmd[1] |= 1;           /* Don't wait for completion */
3225                 timeout = STp->device->request_queue->rq_timeout;
3226         }
3227
3228         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3229                            timeout, MAX_READY_RETRIES, 1);
3230         if (!SRpnt)
3231                 return (STp->buffer)->syscall_result;
3232
3233         STps->drv_block = STps->drv_file = (-1);
3234         STps->eof = ST_NOEOF;
3235         if ((STp->buffer)->syscall_result != 0) {
3236                 result = (-EIO);
3237                 if (STp->can_partitions &&
3238                     (STp->device)->scsi_level >= SCSI_2 &&
3239                     (p = find_partition(STp)) >= 0)
3240                         STp->partition = p;
3241         } else {
3242                 if (STp->can_partitions) {
3243                         STp->partition = partition;
3244                         STps = &(STp->ps[partition]);
3245                         if (!STps->last_block_valid ||
3246                             STps->last_block_visited != block) {
3247                                 STps->at_sm = 0;
3248                                 STps->rw = ST_IDLE;
3249                         }
3250                 } else
3251                         STps->at_sm = 0;
3252                 if (block == 0)
3253                         STps->drv_block = STps->drv_file = 0;
3254                 result = 0;
3255         }
3256
3257         st_release_request(SRpnt);
3258         SRpnt = NULL;
3259
3260         return result;
3261 }
3262
3263
3264 /* Find the current partition number for the drive status. Called from open and
3265    returns either partition number of negative error code. */
3266 static int find_partition(struct scsi_tape *STp)
3267 {
3268         int i, partition;
3269         unsigned int block;
3270
3271         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3272                 return i;
3273         if (partition >= ST_NBR_PARTITIONS)
3274                 return (-EIO);
3275         return partition;
3276 }
3277
3278
3279 /* Change the partition if necessary */
3280 static int switch_partition(struct scsi_tape *STp)
3281 {
3282         struct st_partstat *STps;
3283
3284         if (STp->partition == STp->new_partition)
3285                 return 0;
3286         STps = &(STp->ps[STp->new_partition]);
3287         if (!STps->last_block_valid)
3288                 STps->last_block_visited = 0;
3289         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3290 }
3291 \f
3292 /* Functions for reading and writing the medium partition mode page. */
3293
3294 #define PART_PAGE   0x11
3295 #define PART_PAGE_FIXED_LENGTH 8
3296
3297 #define PP_OFF_MAX_ADD_PARTS   2
3298 #define PP_OFF_NBR_ADD_PARTS   3
3299 #define PP_OFF_FLAGS           4
3300 #define PP_OFF_PART_UNITS      6
3301 #define PP_OFF_RESERVED        7
3302
3303 #define PP_BIT_IDP             0x20
3304 #define PP_BIT_FDP             0x80
3305 #define PP_MSK_PSUM_MB         0x10
3306 #define PP_MSK_PSUM_UNITS      0x18
3307 #define PP_MSK_POFM            0x04
3308
3309 /* Get the number of partitions on the tape. As a side effect reads the
3310    mode page into the tape buffer. */
3311 static int nbr_partitions(struct scsi_tape *STp)
3312 {
3313         int result;
3314
3315         if (STp->ready != ST_READY)
3316                 return (-EIO);
3317
3318         result = read_mode_page(STp, PART_PAGE, 1);
3319
3320         if (result) {
3321                 DEBC_printk(STp, "Can't read medium partition page.\n");
3322                 result = (-EIO);
3323         } else {
3324                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3325                                               PP_OFF_NBR_ADD_PARTS] + 1;
3326                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3327         }
3328
3329         return result;
3330 }
3331
3332
3333 static int format_medium(struct scsi_tape *STp, int format)
3334 {
3335         int result = 0;
3336         int timeout = STp->long_timeout;
3337         unsigned char scmd[MAX_COMMAND_SIZE];
3338         struct st_request *SRpnt;
3339
3340         memset(scmd, 0, MAX_COMMAND_SIZE);
3341         scmd[0] = FORMAT_UNIT;
3342         scmd[2] = format;
3343         if (STp->immediate) {
3344                 scmd[1] |= 1;           /* Don't wait for completion */
3345                 timeout = STp->device->request_queue->rq_timeout;
3346         }
3347         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3348         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3349                            timeout, MAX_RETRIES, 1);
3350         if (!SRpnt)
3351                 result = STp->buffer->syscall_result;
3352         return result;
3353 }
3354
3355
3356 /* Partition the tape into two partitions if size > 0 or one partition if
3357    size == 0.
3358
3359    The block descriptors are read and written because Sony SDT-7000 does not
3360    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3361
3362    My HP C1533A drive returns only one partition size field. This is used to
3363    set the size of partition 1. There is no size field for the default partition.
3364    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3365    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3366    The following algorithm is used to accommodate both drives: if the number of
3367    partition size fields is greater than the maximum number of additional partitions
3368    in the mode page, the second field is used. Otherwise the first field is used.
3369
3370    For Seagate DDS drives the page length must be 8 when no partitions is defined
3371    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3372    is acceptable also to some other old drives and enforced if the first partition
3373    size field is used for the first additional partition size.
3374
3375    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3376  */
3377 static int partition_tape(struct scsi_tape *STp, int size)
3378 {
3379         int result;
3380         int target_partition;
3381         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3382         int pgo, psd_cnt, psdo;
3383         int psum = PP_MSK_PSUM_MB, units = 0;
3384         unsigned char *bp;
3385
3386         result = read_mode_page(STp, PART_PAGE, 0);
3387         if (result) {
3388                 DEBC_printk(STp, "Can't read partition mode page.\n");
3389                 return result;
3390         }
3391         target_partition = 1;
3392         if (size < 0) {
3393                 target_partition = 0;
3394                 size = -size;
3395         }
3396
3397         /* The mode page is in the buffer. Let's modify it and write it. */
3398         bp = (STp->buffer)->b_data;
3399         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3400         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3401                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3402
3403         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3404
3405         if (scsi3) {
3406                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3407                 if (needs_format && size == 0) {
3408                         /* No need to write the mode page when clearing
3409                          *  partitioning
3410                          */
3411                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3412                         result = format_medium(STp, 0);
3413                         goto out;
3414                 }
3415                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3416                         psd_cnt = 2;
3417                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3418                         /* Use units scaling for large partitions if the device
3419                          * suggests it and no precision lost. Required for IBM
3420                          * TS1140/50 drives that don't support MB units.
3421                          */
3422                         if (size >= 1000 && (size % 1000) == 0) {
3423                                 size /= 1000;
3424                                 psum = PP_MSK_PSUM_UNITS;
3425                                 units = 9; /* GB */
3426                         }
3427                 }
3428                 /* Try it anyway if too large to specify in MB */
3429                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3430                         size /= 1000;
3431                         psum = PP_MSK_PSUM_UNITS;
3432                         units = 9;  /* GB */
3433                 }
3434         }
3435
3436         if (size >= 65535 ||  /* Does not fit into two bytes */
3437             (target_partition == 0 && psd_cnt < 2)) {
3438                 result = -EINVAL;
3439                 goto out;
3440         }
3441
3442         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3443         /* The second condition is for HP DDS which use only one partition size
3444          * descriptor
3445          */
3446         if (target_partition > 0 &&
3447             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3448              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3449                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3450                 psdo += 2;
3451         }
3452         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3453
3454         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3455                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3456                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3457
3458         if (size == 0) {
3459                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3460                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3461                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3462                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3463         } else {
3464                 bp[psdo] = (size >> 8) & 0xff;
3465                 bp[psdo + 1] = size & 0xff;
3466                 if (target_partition == 0)
3467                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3468                 bp[pgo + 3] = 1;
3469                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3470                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3471                 DEBC_printk(STp,
3472                             "Formatting tape with two partitions (%i = %d MB).\n",
3473                             target_partition, units > 0 ? size * 1000 : size);
3474         }
3475         bp[pgo + PP_OFF_PART_UNITS] = 0;
3476         bp[pgo + PP_OFF_RESERVED] = 0;
3477         if (size != 1 || units != 0) {
3478                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3479                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3480                 bp[pgo + PP_OFF_PART_UNITS] = units;
3481         } else
3482                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3483                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3484         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3485
3486         result = write_mode_page(STp, PART_PAGE, 1);
3487
3488         if (!result && needs_format)
3489                 result = format_medium(STp, 1);
3490
3491         if (result) {
3492                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3493                 result = (-EIO);
3494         }
3495
3496 out:
3497         return result;
3498 }
3499 \f
3500
3501
3502 /* The ioctl command */
3503 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3504 {
3505         void __user *p = (void __user *)arg;
3506         int i, cmd_nr, cmd_type, bt;
3507         int retval = 0;
3508         unsigned int blk;
3509         struct scsi_tape *STp = file->private_data;
3510         struct st_modedef *STm;
3511         struct st_partstat *STps;
3512
3513         if (mutex_lock_interruptible(&STp->lock))
3514                 return -ERESTARTSYS;
3515
3516         DEB(
3517         if (debugging && !STp->in_use) {
3518                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3519                 retval = (-EIO);
3520                 goto out;
3521         } ) /* end DEB */
3522
3523         STm = &(STp->modes[STp->current_mode]);
3524         STps = &(STp->ps[STp->partition]);
3525
3526         /*
3527          * If we are in the middle of error recovery, don't let anyone
3528          * else try and use this device.  Also, if error recovery fails, it
3529          * may try and take the device offline, in which case all further
3530          * access to the device is prohibited.
3531          */
3532         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3533                         file->f_flags & O_NDELAY);
3534         if (retval)
3535                 goto out;
3536
3537         cmd_type = _IOC_TYPE(cmd_in);
3538         cmd_nr = _IOC_NR(cmd_in);
3539
3540         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3541                 struct mtop mtc;
3542
3543                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3544                         retval = (-EINVAL);
3545                         goto out;
3546                 }
3547
3548                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3549                 if (i) {
3550                         retval = (-EFAULT);
3551                         goto out;
3552                 }
3553
3554                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3555                         st_printk(KERN_WARNING, STp,
3556                                   "MTSETDRVBUFFER only allowed for root.\n");
3557                         retval = (-EPERM);
3558                         goto out;
3559                 }
3560                 if (!STm->defined &&
3561                     (mtc.mt_op != MTSETDRVBUFFER &&
3562                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3563                         retval = (-ENXIO);
3564                         goto out;
3565                 }
3566
3567                 if (!STp->pos_unknown) {
3568
3569                         if (STps->eof == ST_FM_HIT) {
3570                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3571                                     mtc.mt_op == MTEOM) {
3572                                         mtc.mt_count -= 1;
3573                                         if (STps->drv_file >= 0)
3574                                                 STps->drv_file += 1;
3575                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3576                                         mtc.mt_count += 1;
3577                                         if (STps->drv_file >= 0)
3578                                                 STps->drv_file += 1;
3579                                 }
3580                         }
3581
3582                         if (mtc.mt_op == MTSEEK) {
3583                                 /* Old position must be restored if partition will be
3584                                    changed */
3585                                 i = !STp->can_partitions ||
3586                                     (STp->new_partition != STp->partition);
3587                         } else {
3588                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3589                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3590                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3591                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3592                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3593                                     mtc.mt_op == MTCOMPRESSION;
3594                         }
3595                         i = flush_buffer(STp, i);
3596                         if (i < 0) {
3597                                 retval = i;
3598                                 goto out;
3599                         }
3600                         if (STps->rw == ST_WRITING &&
3601                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3602                              mtc.mt_op == MTSEEK ||
3603                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3604                                 i = st_int_ioctl(STp, MTWEOF, 1);
3605                                 if (i < 0) {
3606                                         retval = i;
3607                                         goto out;
3608                                 }
3609                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3610                                         mtc.mt_count++;
3611                                 STps->rw = ST_IDLE;
3612                              }
3613
3614                 } else {
3615                         /*
3616                          * If there was a bus reset, block further access
3617                          * to this device.  If the user wants to rewind the tape,
3618                          * then reset the flag and allow access again.
3619                          */
3620                         if (mtc.mt_op != MTREW &&
3621                             mtc.mt_op != MTOFFL &&
3622                             mtc.mt_op != MTRETEN &&
3623                             mtc.mt_op != MTERASE &&
3624                             mtc.mt_op != MTSEEK &&
3625                             mtc.mt_op != MTEOM) {
3626                                 retval = (-EIO);
3627                                 goto out;
3628                         }
3629                         reset_state(STp);
3630                         /* remove this when the midlevel properly clears was_reset */
3631                         STp->device->was_reset = 0;
3632                 }
3633
3634                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3635                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3636                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3637                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3638
3639                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3640                         do_door_lock(STp, 0);   /* Ignore result! */
3641
3642                 if (mtc.mt_op == MTSETDRVBUFFER &&
3643                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3644                         retval = st_set_options(STp, mtc.mt_count);
3645                         goto out;
3646                 }
3647
3648                 if (mtc.mt_op == MTSETPART) {
3649                         if (!STp->can_partitions ||
3650                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3651                                 retval = (-EINVAL);
3652                                 goto out;
3653                         }
3654                         if (mtc.mt_count >= STp->nbr_partitions &&
3655                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3656                                 retval = (-EIO);
3657                                 goto out;
3658                         }
3659                         if (mtc.mt_count >= STp->nbr_partitions) {
3660                                 retval = (-EINVAL);
3661                                 goto out;
3662                         }
3663                         STp->new_partition = mtc.mt_count;
3664                         retval = 0;
3665                         goto out;
3666                 }
3667
3668                 if (mtc.mt_op == MTMKPART) {
3669                         if (!STp->can_partitions) {
3670                                 retval = (-EINVAL);
3671                                 goto out;
3672                         }
3673                         i = do_load_unload(STp, file, 1);
3674                         if (i < 0) {
3675                                 retval = i;
3676                                 goto out;
3677                         }
3678                         i = partition_tape(STp, mtc.mt_count);
3679                         if (i < 0) {
3680                                 retval = i;
3681                                 goto out;
3682                         }
3683                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3684                                 STp->ps[i].rw = ST_IDLE;
3685                                 STp->ps[i].at_sm = 0;
3686                                 STp->ps[i].last_block_valid = 0;
3687                         }
3688                         STp->partition = STp->new_partition = 0;
3689                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3690                         STps->drv_block = STps->drv_file = 0;
3691                         retval = 0;
3692                         goto out;
3693                 }
3694
3695                 if (mtc.mt_op == MTSEEK) {
3696                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3697                         if (!STp->can_partitions)
3698                                 STp->ps[0].rw = ST_IDLE;
3699                         retval = i;
3700                         goto out;
3701                 }
3702
3703                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3704                         retval = do_load_unload(STp, file, 0);
3705                         goto out;
3706                 }
3707
3708                 if (mtc.mt_op == MTLOAD) {
3709                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3710                         goto out;
3711                 }
3712
3713                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3714                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3715                         goto out;
3716                 }
3717
3718                 if (STp->can_partitions && STp->ready == ST_READY &&
3719                     (i = switch_partition(STp)) < 0) {
3720                         retval = i;
3721                         goto out;
3722                 }
3723
3724                 if (mtc.mt_op == MTCOMPRESSION)
3725                         retval = st_compression(STp, (mtc.mt_count & 1));
3726                 else
3727                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3728                 goto out;
3729         }
3730         if (!STm->defined) {
3731                 retval = (-ENXIO);
3732                 goto out;
3733         }
3734
3735         if ((i = flush_buffer(STp, 0)) < 0) {
3736                 retval = i;
3737                 goto out;
3738         }
3739         if (STp->can_partitions &&
3740             (i = switch_partition(STp)) < 0) {
3741                 retval = i;
3742                 goto out;
3743         }
3744
3745         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3746                 struct mtget mt_status;
3747
3748                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3749                          retval = (-EINVAL);
3750                          goto out;
3751                 }
3752
3753                 mt_status.mt_type = STp->tape_type;
3754                 mt_status.mt_dsreg =
3755                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3756                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3757                 mt_status.mt_blkno = STps->drv_block;
3758                 mt_status.mt_fileno = STps->drv_file;
3759                 if (STp->block_size != 0) {
3760                         if (STps->rw == ST_WRITING)
3761                                 mt_status.mt_blkno +=
3762                                     (STp->buffer)->buffer_bytes / STp->block_size;
3763                         else if (STps->rw == ST_READING)
3764                                 mt_status.mt_blkno -=
3765                                         ((STp->buffer)->buffer_bytes +
3766                                          STp->block_size - 1) / STp->block_size;
3767                 }
3768
3769                 mt_status.mt_gstat = 0;
3770                 if (STp->drv_write_prot)
3771                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3772                 if (mt_status.mt_blkno == 0) {
3773                         if (mt_status.mt_fileno == 0)
3774                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3775                         else
3776                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3777                 }
3778                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3779                 mt_status.mt_resid = STp->partition;
3780                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3781                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3782                 else if (STps->eof >= ST_EOM_OK)
3783                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3784                 if (STp->density == 1)
3785                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3786                 else if (STp->density == 2)
3787                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3788                 else if (STp->density == 3)
3789                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3790                 if (STp->ready == ST_READY)
3791                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3792                 if (STp->ready == ST_NO_TAPE)
3793                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3794                 if (STps->at_sm)
3795                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3796                 if (STm->do_async_writes ||
3797                     (STm->do_buffer_writes && STp->block_size != 0) ||
3798                     STp->drv_buffer != 0)
3799                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3800                 if (STp->cleaning_req)
3801                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3802
3803                 retval = put_user_mtget(p, &mt_status);
3804                 if (retval)
3805                         goto out;
3806
3807                 STp->recover_reg = 0;           /* Clear after read */
3808                 goto out;
3809         }                       /* End of MTIOCGET */
3810         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3811                 struct mtpos mt_pos;
3812                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3813                          retval = (-EINVAL);
3814                          goto out;
3815                 }
3816                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3817                         retval = i;
3818                         goto out;
3819                 }
3820                 mt_pos.mt_blkno = blk;
3821                 retval = put_user_mtpos(p, &mt_pos);
3822                 goto out;
3823         }
3824         mutex_unlock(&STp->lock);
3825
3826         switch (cmd_in) {
3827         case SG_IO:
3828         case SCSI_IOCTL_SEND_COMMAND:
3829         case CDROM_SEND_PACKET:
3830                 if (!capable(CAP_SYS_RAWIO))
3831                         return -EPERM;
3832                 break;
3833         default:
3834                 break;
3835         }
3836
3837         retval = scsi_ioctl(STp->device, file->f_mode & FMODE_WRITE, cmd_in, p);
3838         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) {
3839                 /* unload */
3840                 STp->rew_at_close = 0;
3841                 STp->ready = ST_NO_TAPE;
3842         }
3843         return retval;
3844
3845  out:
3846         mutex_unlock(&STp->lock);
3847         return retval;
3848 }
3849
3850 #ifdef CONFIG_COMPAT
3851 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3852 {
3853         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3854         switch (cmd_in) {
3855         case MTIOCPOS32:
3856                 cmd_in = MTIOCPOS;
3857                 break;
3858         case MTIOCGET32:
3859                 cmd_in = MTIOCGET;
3860                 break;
3861         }
3862
3863         return st_ioctl(file, cmd_in, arg);
3864 }
3865 #endif
3866
3867 \f
3868
3869 /* Try to allocate a new tape buffer. Calling function must not hold
3870    dev_arr_lock. */
3871 static struct st_buffer *new_tape_buffer(int max_sg)
3872 {
3873         struct st_buffer *tb;
3874
3875         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3876         if (!tb) {
3877                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3878                 return NULL;
3879         }
3880         tb->frp_segs = 0;
3881         tb->use_sg = max_sg;
3882         tb->buffer_size = 0;
3883
3884         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3885                                      GFP_KERNEL);
3886         if (!tb->reserved_pages) {
3887                 kfree(tb);
3888                 return NULL;
3889         }
3890
3891         return tb;
3892 }
3893
3894
3895 /* Try to allocate enough space in the tape buffer */
3896 #define ST_MAX_ORDER 6
3897
3898 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size)
3899 {
3900         int segs, max_segs, b_size, order, got;
3901         gfp_t priority;
3902
3903         if (new_size <= STbuffer->buffer_size)
3904                 return 1;
3905
3906         if (STbuffer->buffer_size <= PAGE_SIZE)
3907                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3908
3909         max_segs = STbuffer->use_sg;
3910
3911         priority = GFP_KERNEL | __GFP_NOWARN;
3912
3913         if (STbuffer->cleared)
3914                 priority |= __GFP_ZERO;
3915
3916         if (STbuffer->frp_segs) {
3917                 order = STbuffer->reserved_page_order;
3918                 b_size = PAGE_SIZE << order;
3919         } else {
3920                 for (b_size = PAGE_SIZE, order = 0;
3921                      order < ST_MAX_ORDER &&
3922                              max_segs * (PAGE_SIZE << order) < new_size;
3923                      order++, b_size *= 2)
3924                         ;  /* empty */
3925                 STbuffer->reserved_page_order = order;
3926         }
3927         if (max_segs * (PAGE_SIZE << order) < new_size) {
3928                 if (order == ST_MAX_ORDER)
3929                         return 0;
3930                 normalize_buffer(STbuffer);
3931                 return enlarge_buffer(STbuffer, new_size);
3932         }
3933
3934         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3935              segs < max_segs && got < new_size;) {
3936                 struct page *page;
3937
3938                 page = alloc_pages(priority, order);
3939                 if (!page) {
3940                         DEB(STbuffer->buffer_size = got);
3941                         normalize_buffer(STbuffer);
3942                         return 0;
3943                 }
3944
3945                 STbuffer->frp_segs += 1;
3946                 got += b_size;
3947                 STbuffer->buffer_size = got;
3948                 STbuffer->reserved_pages[segs] = page;
3949                 segs++;
3950         }
3951         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3952
3953         return 1;
3954 }
3955
3956
3957 /* Make sure that no data from previous user is in the internal buffer */
3958 static void clear_buffer(struct st_buffer * st_bp)
3959 {
3960         int i;
3961
3962         for (i=0; i < st_bp->frp_segs; i++)
3963                 memset(page_address(st_bp->reserved_pages[i]), 0,
3964                        PAGE_SIZE << st_bp->reserved_page_order);
3965         st_bp->cleared = 1;
3966 }
3967
3968
3969 /* Release the extra buffer */
3970 static void normalize_buffer(struct st_buffer * STbuffer)
3971 {
3972         int i, order = STbuffer->reserved_page_order;
3973
3974         for (i = 0; i < STbuffer->frp_segs; i++) {
3975                 __free_pages(STbuffer->reserved_pages[i], order);
3976                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3977         }
3978         STbuffer->frp_segs = 0;
3979         STbuffer->sg_segs = 0;
3980         STbuffer->reserved_page_order = 0;
3981         STbuffer->map_data.offset = 0;
3982 }
3983
3984
3985 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3986    negative error code. */
3987 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3988 {
3989         int i, cnt, res, offset;
3990         int length = PAGE_SIZE << st_bp->reserved_page_order;
3991
3992         for (i = 0, offset = st_bp->buffer_bytes;
3993              i < st_bp->frp_segs && offset >= length; i++)
3994                 offset -= length;
3995         if (i == st_bp->frp_segs) {     /* Should never happen */
3996                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3997                 return (-EIO);
3998         }
3999         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4000                 struct page *page = st_bp->reserved_pages[i];
4001                 cnt = length - offset < do_count ? length - offset : do_count;
4002                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4003                 if (res)
4004                         return (-EFAULT);
4005                 do_count -= cnt;
4006                 st_bp->buffer_bytes += cnt;
4007                 ubp += cnt;
4008                 offset = 0;
4009         }
4010         if (do_count) /* Should never happen */
4011                 return (-EIO);
4012
4013         return 0;
4014 }
4015
4016
4017 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4018    negative error code. */
4019 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4020 {
4021         int i, cnt, res, offset;
4022         int length = PAGE_SIZE << st_bp->reserved_page_order;
4023
4024         for (i = 0, offset = st_bp->read_pointer;
4025              i < st_bp->frp_segs && offset >= length; i++)
4026                 offset -= length;
4027         if (i == st_bp->frp_segs) {     /* Should never happen */
4028                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4029                 return (-EIO);
4030         }
4031         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4032                 struct page *page = st_bp->reserved_pages[i];
4033                 cnt = length - offset < do_count ? length - offset : do_count;
4034                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4035                 if (res)
4036                         return (-EFAULT);
4037                 do_count -= cnt;
4038                 st_bp->buffer_bytes -= cnt;
4039                 st_bp->read_pointer += cnt;
4040                 ubp += cnt;
4041                 offset = 0;
4042         }
4043         if (do_count) /* Should never happen */
4044                 return (-EIO);
4045
4046         return 0;
4047 }
4048
4049
4050 /* Move data towards start of buffer */
4051 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4052 {
4053         int src_seg, dst_seg, src_offset = 0, dst_offset;
4054         int count, total;
4055         int length = PAGE_SIZE << st_bp->reserved_page_order;
4056
4057         if (offset == 0)
4058                 return;
4059
4060         total=st_bp->buffer_bytes - offset;
4061         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4062                 src_offset = offset;
4063                 if (src_offset < length)
4064                         break;
4065                 offset -= length;
4066         }
4067
4068         st_bp->buffer_bytes = st_bp->read_pointer = total;
4069         for (dst_seg=dst_offset=0; total > 0; ) {
4070                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4071                 struct page *spage = st_bp->reserved_pages[src_seg];
4072
4073                 count = min(length - dst_offset, length - src_offset);
4074                 memmove(page_address(dpage) + dst_offset,
4075                         page_address(spage) + src_offset, count);
4076                 src_offset += count;
4077                 if (src_offset >= length) {
4078                         src_seg++;
4079                         src_offset = 0;
4080                 }
4081                 dst_offset += count;
4082                 if (dst_offset >= length) {
4083                         dst_seg++;
4084                         dst_offset = 0;
4085                 }
4086                 total -= count;
4087         }
4088 }
4089
4090 /* Validate the options from command line or module parameters */
4091 static void validate_options(void)
4092 {
4093         if (buffer_kbs > 0)
4094                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4095         if (max_sg_segs >= ST_FIRST_SG)
4096                 st_max_sg_segs = max_sg_segs;
4097 }
4098
4099 #ifndef MODULE
4100 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4101  */
4102 static int __init st_setup(char *str)
4103 {
4104         int i, len, ints[5];
4105         char *stp;
4106
4107         stp = get_options(str, ARRAY_SIZE(ints), ints);
4108
4109         if (ints[0] > 0) {
4110                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4111                         if (parms[i].val)
4112                                 *parms[i].val = ints[i + 1];
4113         } else {
4114                 while (stp != NULL) {
4115                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4116                                 len = strlen(parms[i].name);
4117                                 if (!strncmp(stp, parms[i].name, len) &&
4118                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4119                                         if (parms[i].val)
4120                                                 *parms[i].val =
4121                                                         simple_strtoul(stp + len + 1, NULL, 0);
4122                                         else
4123                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4124                                                        parms[i].name);
4125                                         break;
4126                                 }
4127                         }
4128                         if (i >= ARRAY_SIZE(parms))
4129                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4130                                         stp);
4131                         stp = strchr(stp, ',');
4132                         if (stp)
4133                                 stp++;
4134                 }
4135         }
4136
4137         validate_options();
4138
4139         return 1;
4140 }
4141
4142 __setup("st=", st_setup);
4143
4144 #endif
4145
4146 static const struct file_operations st_fops =
4147 {
4148         .owner =        THIS_MODULE,
4149         .read =         st_read,
4150         .write =        st_write,
4151         .unlocked_ioctl = st_ioctl,
4152 #ifdef CONFIG_COMPAT
4153         .compat_ioctl = st_compat_ioctl,
4154 #endif
4155         .open =         st_open,
4156         .flush =        st_flush,
4157         .release =      st_release,
4158         .llseek =       noop_llseek,
4159 };
4160
4161 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4162 {
4163         int i, error;
4164         dev_t cdev_devno;
4165         struct cdev *cdev;
4166         struct device *dev;
4167         struct st_modedef *STm = &(tape->modes[mode]);
4168         char name[10];
4169         int dev_num = tape->index;
4170
4171         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4172
4173         cdev = cdev_alloc();
4174         if (!cdev) {
4175                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4176                 error = -ENOMEM;
4177                 goto out;
4178         }
4179         cdev->owner = THIS_MODULE;
4180         cdev->ops = &st_fops;
4181         STm->cdevs[rew] = cdev;
4182
4183         error = cdev_add(cdev, cdev_devno, 1);
4184         if (error) {
4185                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4186                        rew ? "non" : "auto", mode);
4187                 pr_err("st%d: Device not attached.\n", dev_num);
4188                 goto out_free;
4189         }
4190
4191         i = mode << (4 - ST_NBR_MODE_BITS);
4192         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4193                  tape->name, st_formats[i]);
4194
4195         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4196                             cdev_devno, &tape->modes[mode], "%s", name);
4197         if (IS_ERR(dev)) {
4198                 pr_err("st%d: device_create failed\n", dev_num);
4199                 error = PTR_ERR(dev);
4200                 goto out_free;
4201         }
4202
4203         STm->devs[rew] = dev;
4204
4205         return 0;
4206 out_free:
4207         cdev_del(STm->cdevs[rew]);
4208 out:
4209         STm->cdevs[rew] = NULL;
4210         STm->devs[rew] = NULL;
4211         return error;
4212 }
4213
4214 static int create_cdevs(struct scsi_tape *tape)
4215 {
4216         int mode, error;
4217         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4218                 error = create_one_cdev(tape, mode, 0);
4219                 if (error)
4220                         return error;
4221                 error = create_one_cdev(tape, mode, 1);
4222                 if (error)
4223                         return error;
4224         }
4225
4226         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4227                                  &tape->modes[0].devs[0]->kobj, "tape");
4228 }
4229
4230 static void remove_cdevs(struct scsi_tape *tape)
4231 {
4232         int mode, rew;
4233         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4234         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4235                 struct st_modedef *STm = &(tape->modes[mode]);
4236                 for (rew = 0; rew < 2; rew++) {
4237                         if (STm->cdevs[rew])
4238                                 cdev_del(STm->cdevs[rew]);
4239                         if (STm->devs[rew])
4240                                 device_unregister(STm->devs[rew]);
4241                 }
4242         }
4243 }
4244
4245 static int st_probe(struct device *dev)
4246 {
4247         struct scsi_device *SDp = to_scsi_device(dev);
4248         struct scsi_tape *tpnt = NULL;
4249         struct st_modedef *STm;
4250         struct st_partstat *STps;
4251         struct st_buffer *buffer;
4252         int i, error;
4253
4254         if (SDp->type != TYPE_TAPE)
4255                 return -ENODEV;
4256         if (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         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4277         if (tpnt == NULL) {
4278                 sdev_printk(KERN_ERR, SDp,
4279                             "st: Can't allocate device descriptor.\n");
4280                 goto out_buffer_free;
4281         }
4282         kref_init(&tpnt->kref);
4283
4284         tpnt->device = SDp;
4285         if (SDp->scsi_level <= 2)
4286                 tpnt->tape_type = MT_ISSCSI1;
4287         else
4288                 tpnt->tape_type = MT_ISSCSI2;
4289
4290         tpnt->buffer = buffer;
4291         tpnt->buffer->last_SRpnt = NULL;
4292
4293         tpnt->inited = 0;
4294         tpnt->dirty = 0;
4295         tpnt->in_use = 0;
4296         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4297         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4298         tpnt->density = 0;
4299         tpnt->do_auto_lock = ST_AUTO_LOCK;
4300         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4301         tpnt->can_partitions = 0;
4302         tpnt->two_fm = ST_TWO_FM;
4303         tpnt->fast_mteom = ST_FAST_MTEOM;
4304         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4305         tpnt->sili = ST_SILI;
4306         tpnt->immediate = ST_NOWAIT;
4307         tpnt->immediate_filemark = 0;
4308         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4309         tpnt->partition = 0;
4310         tpnt->new_partition = 0;
4311         tpnt->nbr_partitions = 0;
4312         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4313         tpnt->long_timeout = ST_LONG_TIMEOUT;
4314         tpnt->try_dio = try_direct_io;
4315
4316         for (i = 0; i < ST_NBR_MODES; i++) {
4317                 STm = &(tpnt->modes[i]);
4318                 STm->defined = 0;
4319                 STm->sysv = ST_SYSV;
4320                 STm->defaults_for_writes = 0;
4321                 STm->do_async_writes = ST_ASYNC_WRITES;
4322                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4323                 STm->do_read_ahead = ST_READ_AHEAD;
4324                 STm->default_compression = ST_DONT_TOUCH;
4325                 STm->default_blksize = (-1);    /* No forced size */
4326                 STm->default_density = (-1);    /* No forced density */
4327                 STm->tape = tpnt;
4328         }
4329
4330         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4331                 STps = &(tpnt->ps[i]);
4332                 STps->rw = ST_IDLE;
4333                 STps->eof = ST_NOEOF;
4334                 STps->at_sm = 0;
4335                 STps->last_block_valid = 0;
4336                 STps->drv_block = (-1);
4337                 STps->drv_file = (-1);
4338         }
4339
4340         tpnt->current_mode = 0;
4341         tpnt->modes[0].defined = 1;
4342
4343         tpnt->density_changed = tpnt->compression_changed =
4344             tpnt->blksize_changed = 0;
4345         mutex_init(&tpnt->lock);
4346
4347         idr_preload(GFP_KERNEL);
4348         spin_lock(&st_index_lock);
4349         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4350         spin_unlock(&st_index_lock);
4351         idr_preload_end();
4352         if (error < 0) {
4353                 pr_warn("st: idr allocation failed: %d\n", error);
4354                 goto out_free_tape;
4355         }
4356         tpnt->index = error;
4357         sprintf(tpnt->name, "st%d", tpnt->index);
4358         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4359         if (tpnt->stats == NULL) {
4360                 sdev_printk(KERN_ERR, SDp,
4361                             "st: Can't allocate statistics.\n");
4362                 goto out_idr_remove;
4363         }
4364
4365         dev_set_drvdata(dev, tpnt);
4366
4367
4368         error = create_cdevs(tpnt);
4369         if (error)
4370                 goto out_remove_devs;
4371         scsi_autopm_put_device(SDp);
4372
4373         sdev_printk(KERN_NOTICE, SDp,
4374                     "Attached scsi tape %s\n", tpnt->name);
4375         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4376                     tpnt->name, tpnt->try_dio ? "yes" : "no",
4377                     queue_dma_alignment(SDp->request_queue) + 1);
4378
4379         return 0;
4380
4381 out_remove_devs:
4382         remove_cdevs(tpnt);
4383         kfree(tpnt->stats);
4384 out_idr_remove:
4385         spin_lock(&st_index_lock);
4386         idr_remove(&st_index_idr, tpnt->index);
4387         spin_unlock(&st_index_lock);
4388 out_free_tape:
4389         kfree(tpnt);
4390 out_buffer_free:
4391         kfree(buffer);
4392 out:
4393         scsi_autopm_put_device(SDp);
4394         return -ENODEV;
4395 };
4396
4397
4398 static int st_remove(struct device *dev)
4399 {
4400         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4401         int index = tpnt->index;
4402
4403         scsi_autopm_get_device(to_scsi_device(dev));
4404         remove_cdevs(tpnt);
4405
4406         mutex_lock(&st_ref_mutex);
4407         kref_put(&tpnt->kref, scsi_tape_release);
4408         mutex_unlock(&st_ref_mutex);
4409         spin_lock(&st_index_lock);
4410         idr_remove(&st_index_idr, index);
4411         spin_unlock(&st_index_lock);
4412         return 0;
4413 }
4414
4415 /**
4416  *      scsi_tape_release - Called to free the Scsi_Tape structure
4417  *      @kref: pointer to embedded kref
4418  *
4419  *      st_ref_mutex must be held entering this routine.  Because it is
4420  *      called on last put, you should always use the scsi_tape_get()
4421  *      scsi_tape_put() helpers which manipulate the semaphore directly
4422  *      and never do a direct kref_put().
4423  **/
4424 static void scsi_tape_release(struct kref *kref)
4425 {
4426         struct scsi_tape *tpnt = to_scsi_tape(kref);
4427
4428         tpnt->device = NULL;
4429
4430         if (tpnt->buffer) {
4431                 normalize_buffer(tpnt->buffer);
4432                 kfree(tpnt->buffer->reserved_pages);
4433                 kfree(tpnt->buffer);
4434         }
4435
4436         kfree(tpnt->stats);
4437         kfree(tpnt);
4438         return;
4439 }
4440
4441 static struct class st_sysfs_class = {
4442         .name = "scsi_tape",
4443         .dev_groups = st_dev_groups,
4444 };
4445
4446 static int __init init_st(void)
4447 {
4448         int err;
4449
4450         validate_options();
4451
4452         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4453                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4454
4455         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4456         if (debugging) {
4457                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4458                         debugging);
4459         }
4460
4461         err = class_register(&st_sysfs_class);
4462         if (err) {
4463                 pr_err("Unable register sysfs class for SCSI tapes\n");
4464                 return err;
4465         }
4466
4467         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4468                                      ST_MAX_TAPE_ENTRIES, "st");
4469         if (err) {
4470                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4471                        SCSI_TAPE_MAJOR);
4472                 goto err_class;
4473         }
4474
4475         err = scsi_register_driver(&st_template.gendrv);
4476         if (err)
4477                 goto err_chrdev;
4478
4479         return 0;
4480
4481 err_chrdev:
4482         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4483                                  ST_MAX_TAPE_ENTRIES);
4484 err_class:
4485         class_unregister(&st_sysfs_class);
4486         return err;
4487 }
4488
4489 static void __exit exit_st(void)
4490 {
4491         scsi_unregister_driver(&st_template.gendrv);
4492         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4493                                  ST_MAX_TAPE_ENTRIES);
4494         class_unregister(&st_sysfs_class);
4495         idr_destroy(&st_index_idr);
4496         printk(KERN_INFO "st: Unloaded.\n");
4497 }
4498
4499 module_init(init_st);
4500 module_exit(exit_st);
4501
4502
4503 /* The sysfs driver interface. Read-only at the moment */
4504 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4505 {
4506         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4507 }
4508 static DRIVER_ATTR_RO(try_direct_io);
4509
4510 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4511 {
4512         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4513 }
4514 static DRIVER_ATTR_RO(fixed_buffer_size);
4515
4516 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4517 {
4518         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4519 }
4520 static DRIVER_ATTR_RO(max_sg_segs);
4521
4522 static ssize_t version_show(struct device_driver *ddd, char *buf)
4523 {
4524         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4525 }
4526 static DRIVER_ATTR_RO(version);
4527
4528 #if DEBUG
4529 static ssize_t debug_flag_store(struct device_driver *ddp,
4530         const char *buf, size_t count)
4531 {
4532 /* We only care what the first byte of the data is the rest is unused.
4533  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4534  * other values have -EINVAL returned if they are passed in.
4535  */
4536         if (count > 0) {
4537                 if (buf[0] == '0') {
4538                         debugging = NO_DEBUG;
4539                         return count;
4540                 } else if (buf[0] == '1') {
4541                         debugging = 1;
4542                         return count;
4543                 }
4544         }
4545         return -EINVAL;
4546 }
4547
4548 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4549 {
4550         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4551 }
4552 static DRIVER_ATTR_RW(debug_flag);
4553 #endif
4554
4555 static struct attribute *st_drv_attrs[] = {
4556         &driver_attr_try_direct_io.attr,
4557         &driver_attr_fixed_buffer_size.attr,
4558         &driver_attr_max_sg_segs.attr,
4559         &driver_attr_version.attr,
4560 #if DEBUG
4561         &driver_attr_debug_flag.attr,
4562 #endif
4563         NULL,
4564 };
4565 ATTRIBUTE_GROUPS(st_drv);
4566
4567 /* The sysfs simple class interface */
4568 static ssize_t
4569 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4570 {
4571         struct st_modedef *STm = dev_get_drvdata(dev);
4572         ssize_t l = 0;
4573
4574         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4575         return l;
4576 }
4577 static DEVICE_ATTR_RO(defined);
4578
4579 static ssize_t
4580 default_blksize_show(struct device *dev, struct device_attribute *attr,
4581                      char *buf)
4582 {
4583         struct st_modedef *STm = dev_get_drvdata(dev);
4584         ssize_t l = 0;
4585
4586         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4587         return l;
4588 }
4589 static DEVICE_ATTR_RO(default_blksize);
4590
4591 static ssize_t
4592 default_density_show(struct device *dev, struct device_attribute *attr,
4593                      char *buf)
4594 {
4595         struct st_modedef *STm = dev_get_drvdata(dev);
4596         ssize_t l = 0;
4597         char *fmt;
4598
4599         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4600         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4601         return l;
4602 }
4603 static DEVICE_ATTR_RO(default_density);
4604
4605 static ssize_t
4606 default_compression_show(struct device *dev, struct device_attribute *attr,
4607                          char *buf)
4608 {
4609         struct st_modedef *STm = dev_get_drvdata(dev);
4610         ssize_t l = 0;
4611
4612         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4613         return l;
4614 }
4615 static DEVICE_ATTR_RO(default_compression);
4616
4617 static ssize_t
4618 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4619 {
4620         struct st_modedef *STm = dev_get_drvdata(dev);
4621         struct scsi_tape *STp = STm->tape;
4622         int options;
4623         ssize_t l = 0;
4624
4625         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4626         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4627         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4628         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4629         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4630         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4631         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4632         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4633         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4634         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4635         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4636         options |= STm->sysv ? MT_ST_SYSV : 0;
4637         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4638         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4639         options |= STp->sili ? MT_ST_SILI : 0;
4640
4641         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4642         return l;
4643 }
4644 static DEVICE_ATTR_RO(options);
4645
4646 /* Support for tape stats */
4647
4648 /**
4649  * read_cnt_show - return read count - count of reads made from tape drive
4650  * @dev: struct device
4651  * @attr: attribute structure
4652  * @buf: buffer to return formatted data in
4653  */
4654 static ssize_t read_cnt_show(struct device *dev,
4655         struct device_attribute *attr, char *buf)
4656 {
4657         struct st_modedef *STm = dev_get_drvdata(dev);
4658
4659         return sprintf(buf, "%lld",
4660                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4661 }
4662 static DEVICE_ATTR_RO(read_cnt);
4663
4664 /**
4665  * read_byte_cnt_show - return read byte count - tape drives
4666  * may use blocks less than 512 bytes this gives the raw byte count of
4667  * of data read from the tape drive.
4668  * @dev: struct device
4669  * @attr: attribute structure
4670  * @buf: buffer to return formatted data in
4671  */
4672 static ssize_t read_byte_cnt_show(struct device *dev,
4673         struct device_attribute *attr, char *buf)
4674 {
4675         struct st_modedef *STm = dev_get_drvdata(dev);
4676
4677         return sprintf(buf, "%lld",
4678                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4679 }
4680 static DEVICE_ATTR_RO(read_byte_cnt);
4681
4682 /**
4683  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4684  * @dev: struct device
4685  * @attr: attribute structure
4686  * @buf: buffer to return formatted data in
4687  */
4688 static ssize_t read_ns_show(struct device *dev,
4689         struct device_attribute *attr, char *buf)
4690 {
4691         struct st_modedef *STm = dev_get_drvdata(dev);
4692
4693         return sprintf(buf, "%lld",
4694                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4695 }
4696 static DEVICE_ATTR_RO(read_ns);
4697
4698 /**
4699  * write_cnt_show - write count - number of user calls
4700  * to write(2) that have written data to tape.
4701  * @dev: struct device
4702  * @attr: attribute structure
4703  * @buf: buffer to return formatted data in
4704  */
4705 static ssize_t write_cnt_show(struct device *dev,
4706         struct device_attribute *attr, char *buf)
4707 {
4708         struct st_modedef *STm = dev_get_drvdata(dev);
4709
4710         return sprintf(buf, "%lld",
4711                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4712 }
4713 static DEVICE_ATTR_RO(write_cnt);
4714
4715 /**
4716  * write_byte_cnt_show - write byte count - raw count of
4717  * bytes written to tape.
4718  * @dev: struct device
4719  * @attr: attribute structure
4720  * @buf: buffer to return formatted data in
4721  */
4722 static ssize_t write_byte_cnt_show(struct device *dev,
4723         struct device_attribute *attr, char *buf)
4724 {
4725         struct st_modedef *STm = dev_get_drvdata(dev);
4726
4727         return sprintf(buf, "%lld",
4728                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4729 }
4730 static DEVICE_ATTR_RO(write_byte_cnt);
4731
4732 /**
4733  * write_ns_show - write ns - number of nanoseconds waiting on write
4734  * requests to complete.
4735  * @dev: struct device
4736  * @attr: attribute structure
4737  * @buf: buffer to return formatted data in
4738  */
4739 static ssize_t write_ns_show(struct device *dev,
4740         struct device_attribute *attr, char *buf)
4741 {
4742         struct st_modedef *STm = dev_get_drvdata(dev);
4743
4744         return sprintf(buf, "%lld",
4745                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4746 }
4747 static DEVICE_ATTR_RO(write_ns);
4748
4749 /**
4750  * in_flight_show - number of I/Os currently in flight -
4751  * in most cases this will be either 0 or 1. It may be higher if someone
4752  * has also issued other SCSI commands such as via an ioctl.
4753  * @dev: struct device
4754  * @attr: attribute structure
4755  * @buf: buffer to return formatted data in
4756  */
4757 static ssize_t in_flight_show(struct device *dev,
4758         struct device_attribute *attr, char *buf)
4759 {
4760         struct st_modedef *STm = dev_get_drvdata(dev);
4761
4762         return sprintf(buf, "%lld",
4763                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4764 }
4765 static DEVICE_ATTR_RO(in_flight);
4766
4767 /**
4768  * io_ns_show - io wait ns - this is the number of ns spent
4769  * waiting on all I/O to complete. This includes tape movement commands
4770  * such as rewinding, seeking to end of file or tape, it also includes
4771  * read and write. To determine the time spent on tape movement
4772  * subtract the read and write ns from this value.
4773  * @dev: struct device
4774  * @attr: attribute structure
4775  * @buf: buffer to return formatted data in
4776  */
4777 static ssize_t io_ns_show(struct device *dev,
4778         struct device_attribute *attr, char *buf)
4779 {
4780         struct st_modedef *STm = dev_get_drvdata(dev);
4781
4782         return sprintf(buf, "%lld",
4783                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4784 }
4785 static DEVICE_ATTR_RO(io_ns);
4786
4787 /**
4788  * other_cnt_show - other io count - this is the number of
4789  * I/O requests other than read and write requests.
4790  * Typically these are tape movement requests but will include driver
4791  * tape movement. This includes only requests issued by the st driver.
4792  * @dev: struct device
4793  * @attr: attribute structure
4794  * @buf: buffer to return formatted data in
4795  */
4796 static ssize_t other_cnt_show(struct device *dev,
4797         struct device_attribute *attr, char *buf)
4798 {
4799         struct st_modedef *STm = dev_get_drvdata(dev);
4800
4801         return sprintf(buf, "%lld",
4802                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4803 }
4804 static DEVICE_ATTR_RO(other_cnt);
4805
4806 /**
4807  * resid_cnt_show - A count of the number of times we get a residual
4808  * count - this should indicate someone issuing reads larger than the
4809  * block size on tape.
4810  * @dev: struct device
4811  * @attr: attribute structure
4812  * @buf: buffer to return formatted data in
4813  */
4814 static ssize_t resid_cnt_show(struct device *dev,
4815         struct device_attribute *attr, char *buf)
4816 {
4817         struct st_modedef *STm = dev_get_drvdata(dev);
4818
4819         return sprintf(buf, "%lld",
4820                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4821 }
4822 static DEVICE_ATTR_RO(resid_cnt);
4823
4824 static struct attribute *st_dev_attrs[] = {
4825         &dev_attr_defined.attr,
4826         &dev_attr_default_blksize.attr,
4827         &dev_attr_default_density.attr,
4828         &dev_attr_default_compression.attr,
4829         &dev_attr_options.attr,
4830         NULL,
4831 };
4832
4833 static struct attribute *st_stats_attrs[] = {
4834         &dev_attr_read_cnt.attr,
4835         &dev_attr_read_byte_cnt.attr,
4836         &dev_attr_read_ns.attr,
4837         &dev_attr_write_cnt.attr,
4838         &dev_attr_write_byte_cnt.attr,
4839         &dev_attr_write_ns.attr,
4840         &dev_attr_in_flight.attr,
4841         &dev_attr_io_ns.attr,
4842         &dev_attr_other_cnt.attr,
4843         &dev_attr_resid_cnt.attr,
4844         NULL,
4845 };
4846
4847 static struct attribute_group stats_group = {
4848         .name = "stats",
4849         .attrs = st_stats_attrs,
4850 };
4851
4852 static struct attribute_group st_group = {
4853         .attrs = st_dev_attrs,
4854 };
4855
4856 static const struct attribute_group *st_dev_groups[] = {
4857         &st_group,
4858         &stats_group,
4859         NULL,
4860 };
4861
4862 /* The following functions may be useful for a larger audience. */
4863 static int sgl_map_user_pages(struct st_buffer *STbp,
4864                               const unsigned int max_pages, unsigned long uaddr,
4865                               size_t count, int rw)
4866 {
4867         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4868         unsigned long start = uaddr >> PAGE_SHIFT;
4869         const int nr_pages = end - start;
4870         int res, i;
4871         struct page **pages;
4872         struct rq_map_data *mdata = &STbp->map_data;
4873
4874         /* User attempted Overflow! */
4875         if ((uaddr + count) < uaddr)
4876                 return -EINVAL;
4877
4878         /* Too big */
4879         if (nr_pages > max_pages)
4880                 return -ENOMEM;
4881
4882         /* Hmm? */
4883         if (count == 0)
4884                 return 0;
4885
4886         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4887         if (pages == NULL)
4888                 return -ENOMEM;
4889
4890         /* Try to fault in all of the necessary pages */
4891         /* rw==READ means read from drive, write into memory area */
4892         res = pin_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4893                                   pages);
4894
4895         /* Errors and no page mapped should return here */
4896         if (res < nr_pages)
4897                 goto out_unmap;
4898
4899         for (i=0; i < nr_pages; i++) {
4900                 /* FIXME: flush superflous for rw==READ,
4901                  * probably wrong function for rw==WRITE
4902                  */
4903                 flush_dcache_page(pages[i]);
4904         }
4905
4906         mdata->offset = uaddr & ~PAGE_MASK;
4907         STbp->mapped_pages = pages;
4908
4909         return nr_pages;
4910  out_unmap:
4911         if (res > 0) {
4912                 unpin_user_pages(pages, res);
4913                 res = 0;
4914         }
4915         kfree(pages);
4916         return res;
4917 }
4918
4919
4920 /* And unmap them... */
4921 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4922                                 const unsigned int nr_pages, int dirtied)
4923 {
4924         /* FIXME: cache flush missing for rw==READ */
4925         unpin_user_pages_dirty_lock(STbp->mapped_pages, nr_pages, dirtied);
4926
4927         kfree(STbp->mapped_pages);
4928         STbp->mapped_pages = NULL;
4929
4930         return 0;
4931 }