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   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2007 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20070203";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/errno.h>
  31 #include <linux/mtio.h>
  32 #include <linux/cdrom.h>
  33 #include <linux/ioctl.h>
  34 #include <linux/fcntl.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/cdev.h>
  39 #include <linux/delay.h>
  40 #include <linux/mutex.h>
  41
  42 #include <asm/uaccess.h>
  43 #include <asm/dma.h>
  44 #include <asm/system.h>
  45
  46 #include <scsi/scsi.h>
  47 #include <scsi/scsi_dbg.h>
  48 #include <scsi/scsi_device.h>
  49 #include <scsi/scsi_driver.h>
  50 #include <scsi/scsi_eh.h>
  51 #include <scsi/scsi_host.h>
  52 #include <scsi/scsi_ioctl.h>
  53 #include <scsi/sg.h>
  54
  55
  56 /* The driver prints some debugging information on the console if DEBUG
  57    is defined and non-zero. */
  58 #define DEBUG 0
  59
  60 #if DEBUG
  61 /* The message level for the debug messages is currently set to KERN_NOTICE
  62    so that people can easily see the messages. Later when the debugging messages
  63    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  64 #define ST_DEB_MSG  KERN_NOTICE
  65 #define DEB(a) a
  66 #define DEBC(a) if (debugging) { a ; }
  67 #else
  68 #define DEB(a)
  69 #define DEBC(a)
  70 #endif
  71
  72 #define ST_KILOBYTE 1024
  73
  74 #include "st_options.h"
  75 #include "st.h"
  76
  77 static int buffer_kbs;
  78 static int max_sg_segs;
  79 static int try_direct_io = TRY_DIRECT_IO;
  80 static int try_rdio = 1;
  81 static int try_wdio = 1;
  82
  83 static int st_dev_max;
  84 static int st_nr_dev;
  85
  86 static struct class *st_sysfs_class;
  87
  88 MODULE_AUTHOR("Kai Makisara");
  89 MODULE_DESCRIPTION("SCSI tape (st) driver");
  90 MODULE_LICENSE("GPL");
  91 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  92 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  93
  94 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  95  * of sysfs parameters (which module_param doesn't yet support).
  96  * Sysfs parameters defined explicitly later.
  97  */
  98 module_param_named(buffer_kbs, buffer_kbs, int, 0);
  99 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 100 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 101 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 102 module_param_named(try_direct_io, try_direct_io, int, 0);
 103 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 104
 105 /* Extra parameters for testing */
 106 module_param_named(try_rdio, try_rdio, int, 0);
 107 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 108 module_param_named(try_wdio, try_wdio, int, 0);
 109 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 110
 111 #ifndef MODULE
 112 static int write_threshold_kbs;  /* retained for compatibility */
 113 static struct st_dev_parm {
 114         char *name;
 115         int *val;
 116 } parms[] __initdata = {
 117         {
 118                 "buffer_kbs", &buffer_kbs
 119         },
 120         {       /* Retained for compatibility with 2.4 */
 121                 "write_threshold_kbs", &write_threshold_kbs
 122         },
 123         {
 124                 "max_sg_segs", NULL
 125         },
 126         {
 127                 "try_direct_io", &try_direct_io
 128         }
 129 };
 130 #endif
 131
 132 /* Restrict the number of modes so that names for all are assigned */
 133 #if ST_NBR_MODES > 16
 134 #error "Maximum number of modes is 16"
 135 #endif
 136 /* Bit reversed order to get same names for same minors with all
 137    mode counts */
 138 static const char *st_formats[] = {
 139         "",  "r", "k", "s", "l", "t", "o", "u",
 140         "m", "v", "p", "x", "a", "y", "q", "z"};
 141
 142 /* The default definitions have been moved to st_options.h */
 143
 144 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 145
 146 /* The buffer size should fit into the 24 bits for length in the
 147    6-byte SCSI read and write commands. */
 148 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 149 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 150 #endif
 151
 152 static int debugging = DEBUG;
 153
 154 #define MAX_RETRIES 0
 155 #define MAX_WRITE_RETRIES 0
 156 #define MAX_READY_RETRIES 0
 157 #define NO_TAPE  NOT_READY
 158
 159 #define ST_TIMEOUT (900 * HZ)
 160 #define ST_LONG_TIMEOUT (14000 * HZ)
 161
 162 /* Remove mode bits and auto-rewind bit (7) */
 163 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 164     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 165 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 166
 167 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 168 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 169   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 170
 171 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 172    24 bits) */
 173 #define SET_DENS_AND_BLK 0x10001
 174
 175 static DEFINE_RWLOCK(st_dev_arr_lock);
 176
 177 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 178 static int st_max_sg_segs = ST_MAX_SG;
 179
 180 static struct scsi_tape **scsi_tapes = NULL;
 181
 182 static int modes_defined;
 183
 184 static struct st_buffer *new_tape_buffer(int, int, int);
 185 static int enlarge_buffer(struct st_buffer *, int, int);
 186 static void normalize_buffer(struct st_buffer *);
 187 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 188 static int from_buffer(struct st_buffer *, char __user *, int);
 189 static void move_buffer_data(struct st_buffer *, int);
 190 static void buf_to_sg(struct st_buffer *, unsigned int);
 191
 192 static int sgl_map_user_pages(struct scatterlist *, const unsigned int,
 193                               unsigned long, size_t, int);
 194 static int sgl_unmap_user_pages(struct scatterlist *, const unsigned int, int);
 195
 196 static int st_probe(struct device *);
 197 static int st_remove(struct device *);
 198
 199 static int do_create_sysfs_files(void);
 200 static void do_remove_sysfs_files(void);
 201 static int do_create_class_files(struct scsi_tape *, int, int);
 202
 203 static struct scsi_driver st_template = {
 204         .owner                  = THIS_MODULE,
 205         .gendrv = {
 206                 .name           = "st",
 207                 .probe          = st_probe,
 208                 .remove         = st_remove,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224
 225 \f
 226 #include "osst_detect.h"
 227 #ifndef SIGS_FROM_OSST
 228 #define SIGS_FROM_OSST \
 229         {"OnStream", "SC-", "", "osst"}, \
 230         {"OnStream", "DI-", "", "osst"}, \
 231         {"OnStream", "DP-", "", "osst"}, \
 232         {"OnStream", "USB", "", "osst"}, \
 233         {"OnStream", "FW-", "", "osst"}
 234 #endif
 235
 236 static struct scsi_tape *scsi_tape_get(int dev)
 237 {
 238         struct scsi_tape *STp = NULL;
 239
 240         mutex_lock(&st_ref_mutex);
 241         write_lock(&st_dev_arr_lock);
 242
 243         if (dev < st_dev_max && scsi_tapes != NULL)
 244                 STp = scsi_tapes[dev];
 245         if (!STp) goto out;
 246
 247         kref_get(&STp->kref);
 248
 249         if (!STp->device)
 250                 goto out_put;
 251
 252         if (scsi_device_get(STp->device))
 253                 goto out_put;
 254
 255         goto out;
 256
 257 out_put:
 258         kref_put(&STp->kref, scsi_tape_release);
 259         STp = NULL;
 260 out:
 261         write_unlock(&st_dev_arr_lock);
 262         mutex_unlock(&st_ref_mutex);
 263         return STp;
 264 }
 265
 266 static void scsi_tape_put(struct scsi_tape *STp)
 267 {
 268         struct scsi_device *sdev = STp->device;
 269
 270         mutex_lock(&st_ref_mutex);
 271         kref_put(&STp->kref, scsi_tape_release);
 272         scsi_device_put(sdev);
 273         mutex_unlock(&st_ref_mutex);
 274 }
 275
 276 struct st_reject_data {
 277         char *vendor;
 278         char *model;
 279         char *rev;
 280         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 281 };
 282
 283 static struct st_reject_data reject_list[] = {
 284         /* {"XXX", "Yy-", "", NULL},  example */
 285         SIGS_FROM_OSST,
 286         {NULL, }};
 287
 288 /* If the device signature is on the list of incompatible drives, the
 289    function returns a pointer to the name of the correct driver (if known) */
 290 static char * st_incompatible(struct scsi_device* SDp)
 291 {
 292         struct st_reject_data *rp;
 293
 294         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 295                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 296                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 297                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 298                         if (rp->driver_hint)
 299                                 return rp->driver_hint;
 300                         else
 301                                 return "unknown";
 302                 }
 303         return NULL;
 304 }
 305 \f
 306
 307 static inline char *tape_name(struct scsi_tape *tape)
 308 {
 309         return tape->disk->disk_name;
 310 }
 311
 312
 313 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 314 {
 315         const u8 *ucp;
 316         const u8 *sense = SRpnt->sense;
 317
 318         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 319                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 320         s->flags = 0;
 321
 322         if (s->have_sense) {
 323                 s->deferred = 0;
 324                 s->remainder_valid =
 325                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 326                 switch (sense[0] & 0x7f) {
 327                 case 0x71:
 328                         s->deferred = 1;
 329                 case 0x70:
 330                         s->fixed_format = 1;
 331                         s->flags = sense[2] & 0xe0;
 332                         break;
 333                 case 0x73:
 334                         s->deferred = 1;
 335                 case 0x72:
 336                         s->fixed_format = 0;
 337                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 338                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 339                         break;
 340                 }
 341         }
 342 }
 343
 344
 345 /* Convert the result to success code */
 346 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 347 {
 348         int result = SRpnt->result;
 349         u8 scode;
 350         DEB(const char *stp;)
 351         char *name = tape_name(STp);
 352         struct st_cmdstatus *cmdstatp;
 353
 354         if (!result)
 355                 return 0;
 356
 357         cmdstatp = &STp->buffer->cmdstat;
 358         st_analyze_sense(SRpnt, cmdstatp);
 359
 360         if (cmdstatp->have_sense)
 361                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 362         else
 363                 scode = 0;
 364
 365         DEB(
 366         if (debugging) {
 367                 printk(ST_DEB_MSG "%s: Error: %x, cmd: %x %x %x %x %x %x\n",
 368                        name, result,
 369                        SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 370                        SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 371                 if (cmdstatp->have_sense)
 372                          __scsi_print_sense(name, SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 373         } ) /* end DEB */
 374         if (!debugging) { /* Abnormal conditions for tape */
 375                 if (!cmdstatp->have_sense)
 376                         printk(KERN_WARNING
 377                                "%s: Error %x (sugg. bt 0x%x, driver bt 0x%x, host bt 0x%x).\n",
 378                                name, result, suggestion(result),
 379                                driver_byte(result) & DRIVER_MASK, host_byte(result));
 380                 else if (cmdstatp->have_sense &&
 381                          scode != NO_SENSE &&
 382                          scode != RECOVERED_ERROR &&
 383                          /* scode != UNIT_ATTENTION && */
 384                          scode != BLANK_CHECK &&
 385                          scode != VOLUME_OVERFLOW &&
 386                          SRpnt->cmd[0] != MODE_SENSE &&
 387                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 388
 389                         __scsi_print_sense(name, SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 390                 }
 391         }
 392
 393         if (cmdstatp->fixed_format &&
 394             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 395                 if (STp->cln_sense_value)
 396                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 397                                                STp->cln_sense_mask) == STp->cln_sense_value);
 398                 else
 399                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 400                                                STp->cln_sense_mask) != 0);
 401         }
 402         if (cmdstatp->have_sense &&
 403             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 404                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 405
 406         STp->pos_unknown |= STp->device->was_reset;
 407
 408         if (cmdstatp->have_sense &&
 409             scode == RECOVERED_ERROR
 410 #if ST_RECOVERED_WRITE_FATAL
 411             && SRpnt->cmd[0] != WRITE_6
 412             && SRpnt->cmd[0] != WRITE_FILEMARKS
 413 #endif
 414             ) {
 415                 STp->recover_count++;
 416                 STp->recover_reg++;
 417
 418                 DEB(
 419                 if (debugging) {
 420                         if (SRpnt->cmd[0] == READ_6)
 421                                 stp = "read";
 422                         else if (SRpnt->cmd[0] == WRITE_6)
 423                                 stp = "write";
 424                         else
 425                                 stp = "ioctl";
 426                         printk(ST_DEB_MSG "%s: Recovered %s error (%d).\n", name, stp,
 427                                STp->recover_count);
 428                 } ) /* end DEB */
 429
 430                 if (cmdstatp->flags == 0)
 431                         return 0;
 432         }
 433         return (-EIO);
 434 }
 435
 436
 437 /* Wakeup from interrupt */
 438 static void st_sleep_done(void *data, char *sense, int result, int resid)
 439 {
 440         struct st_request *SRpnt = data;
 441         struct scsi_tape *STp = SRpnt->stp;
 442
 443         memcpy(SRpnt->sense, sense, SCSI_SENSE_BUFFERSIZE);
 444         (STp->buffer)->cmdstat.midlevel_result = SRpnt->result = result;
 445         DEB( STp->write_pending = 0; )
 446
 447         if (SRpnt->waiting)
 448                 complete(SRpnt->waiting);
 449 }
 450
 451 static struct st_request *st_allocate_request(void)
 452 {
 453         return kzalloc(sizeof(struct st_request), GFP_KERNEL);
 454 }
 455
 456 static void st_release_request(struct st_request *streq)
 457 {
 458         kfree(streq);
 459 }
 460
 461 /* Do the scsi command. Waits until command performed if do_wait is true.
 462    Otherwise write_behind_check() is used to check that the command
 463    has finished. */
 464 static struct st_request *
 465 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 466            int bytes, int direction, int timeout, int retries, int do_wait)
 467 {
 468         struct completion *waiting;
 469
 470         /* if async, make sure there's no command outstanding */
 471         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 472                 printk(KERN_ERR "%s: Async command already active.\n",
 473                        tape_name(STp));
 474                 if (signal_pending(current))
 475                         (STp->buffer)->syscall_result = (-EINTR);
 476                 else
 477                         (STp->buffer)->syscall_result = (-EBUSY);
 478                 return NULL;
 479         }
 480
 481         if (SRpnt == NULL) {
 482                 SRpnt = st_allocate_request();
 483                 if (SRpnt == NULL) {
 484                         DEBC( printk(KERN_ERR "%s: Can't get SCSI request.\n",
 485                                      tape_name(STp)); );
 486                         if (signal_pending(current))
 487                                 (STp->buffer)->syscall_result = (-EINTR);
 488                         else
 489                                 (STp->buffer)->syscall_result = (-EBUSY);
 490                         return NULL;
 491                 }
 492                 SRpnt->stp = STp;
 493         }
 494
 495         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 496            which IO is outstanding. It's nulled out when the IO completes. */
 497         if (!do_wait)
 498                 (STp->buffer)->last_SRpnt = SRpnt;
 499
 500         waiting = &STp->wait;
 501         init_completion(waiting);
 502         SRpnt->waiting = waiting;
 503
 504         if (!STp->buffer->do_dio)
 505                 buf_to_sg(STp->buffer, bytes);
 506
 507         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 508         STp->buffer->cmdstat.have_sense = 0;
 509         STp->buffer->syscall_result = 0;
 510
 511         if (scsi_execute_async(STp->device, cmd, COMMAND_SIZE(cmd[0]), direction,
 512                         &((STp->buffer)->sg[0]), bytes, (STp->buffer)->sg_segs,
 513                                timeout, retries, SRpnt, st_sleep_done, GFP_KERNEL)) {
 514                 /* could not allocate the buffer or request was too large */
 515                 (STp->buffer)->syscall_result = (-EBUSY);
 516                 (STp->buffer)->last_SRpnt = NULL;
 517         }
 518         else if (do_wait) {
 519                 wait_for_completion(waiting);
 520                 SRpnt->waiting = NULL;
 521                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 522         }
 523
 524         return SRpnt;
 525 }
 526
 527
 528 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 529    write has been correct but EOM early warning reached, -EIO if write ended in
 530    error or zero if write successful. Asynchronous writes are used only in
 531    variable block mode. */
 532 static int write_behind_check(struct scsi_tape * STp)
 533 {
 534         int retval = 0;
 535         struct st_buffer *STbuffer;
 536         struct st_partstat *STps;
 537         struct st_cmdstatus *cmdstatp;
 538         struct st_request *SRpnt;
 539
 540         STbuffer = STp->buffer;
 541         if (!STbuffer->writing)
 542                 return 0;
 543
 544         DEB(
 545         if (STp->write_pending)
 546                 STp->nbr_waits++;
 547         else
 548                 STp->nbr_finished++;
 549         ) /* end DEB */
 550
 551         wait_for_completion(&(STp->wait));
 552         SRpnt = STbuffer->last_SRpnt;
 553         STbuffer->last_SRpnt = NULL;
 554         SRpnt->waiting = NULL;
 555
 556         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 557         st_release_request(SRpnt);
 558
 559         STbuffer->buffer_bytes -= STbuffer->writing;
 560         STps = &(STp->ps[STp->partition]);
 561         if (STps->drv_block >= 0) {
 562                 if (STp->block_size == 0)
 563                         STps->drv_block++;
 564                 else
 565                         STps->drv_block += STbuffer->writing / STp->block_size;
 566         }
 567
 568         cmdstatp = &STbuffer->cmdstat;
 569         if (STbuffer->syscall_result) {
 570                 retval = -EIO;
 571                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 572                     (cmdstatp->flags & SENSE_EOM) &&
 573                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 574                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 575                         /* EOM at write-behind, has all data been written? */
 576                         if (!cmdstatp->remainder_valid ||
 577                             cmdstatp->uremainder64 == 0)
 578                                 retval = -ENOSPC;
 579                 }
 580                 if (retval == -EIO)
 581                         STps->drv_block = -1;
 582         }
 583         STbuffer->writing = 0;
 584
 585         DEB(if (debugging && retval)
 586             printk(ST_DEB_MSG "%s: Async write error %x, return value %d.\n",
 587                    tape_name(STp), STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 588
 589         return retval;
 590 }
 591
 592
 593 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 594    it messes up the block number). */
 595 static int cross_eof(struct scsi_tape * STp, int forward)
 596 {
 597         struct st_request *SRpnt;
 598         unsigned char cmd[MAX_COMMAND_SIZE];
 599
 600         cmd[0] = SPACE;
 601         cmd[1] = 0x01;          /* Space FileMarks */
 602         if (forward) {
 603                 cmd[2] = cmd[3] = 0;
 604                 cmd[4] = 1;
 605         } else
 606                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 607         cmd[5] = 0;
 608
 609         DEBC(printk(ST_DEB_MSG "%s: Stepping over filemark %s.\n",
 610                    tape_name(STp), forward ? "forward" : "backward"));
 611
 612         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 613                            STp->device->timeout, MAX_RETRIES, 1);
 614         if (!SRpnt)
 615                 return (STp->buffer)->syscall_result;
 616
 617         st_release_request(SRpnt);
 618         SRpnt = NULL;
 619
 620         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 621                 printk(KERN_ERR "%s: Stepping over filemark %s failed.\n",
 622                    tape_name(STp), forward ? "forward" : "backward");
 623
 624         return (STp->buffer)->syscall_result;
 625 }
 626
 627
 628 /* Flush the write buffer (never need to write if variable blocksize). */
 629 static int flush_write_buffer(struct scsi_tape * STp)
 630 {
 631         int offset, transfer, blks;
 632         int result;
 633         unsigned char cmd[MAX_COMMAND_SIZE];
 634         struct st_request *SRpnt;
 635         struct st_partstat *STps;
 636
 637         result = write_behind_check(STp);
 638         if (result)
 639                 return result;
 640
 641         result = 0;
 642         if (STp->dirty == 1) {
 643
 644                 offset = (STp->buffer)->buffer_bytes;
 645                 transfer = ((offset + STp->block_size - 1) /
 646                             STp->block_size) * STp->block_size;
 647                 DEBC(printk(ST_DEB_MSG "%s: Flushing %d bytes.\n",
 648                                tape_name(STp), transfer));
 649
 650                 memset((STp->buffer)->b_data + offset, 0, transfer - offset);
 651
 652                 memset(cmd, 0, MAX_COMMAND_SIZE);
 653                 cmd[0] = WRITE_6;
 654                 cmd[1] = 1;
 655                 blks = transfer / STp->block_size;
 656                 cmd[2] = blks >> 16;
 657                 cmd[3] = blks >> 8;
 658                 cmd[4] = blks;
 659
 660                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 661                                    STp->device->timeout, MAX_WRITE_RETRIES, 1);
 662                 if (!SRpnt)
 663                         return (STp->buffer)->syscall_result;
 664
 665                 STps = &(STp->ps[STp->partition]);
 666                 if ((STp->buffer)->syscall_result != 0) {
 667                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 668
 669                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 670                             (cmdstatp->flags & SENSE_EOM) &&
 671                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 672                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 673                             (!cmdstatp->remainder_valid ||
 674                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 675                                 STp->dirty = 0;
 676                                 (STp->buffer)->buffer_bytes = 0;
 677                                 if (STps->drv_block >= 0)
 678                                         STps->drv_block += blks;
 679                                 result = (-ENOSPC);
 680                         } else {
 681                                 printk(KERN_ERR "%s: Error on flush.\n",
 682                                        tape_name(STp));
 683                                 STps->drv_block = (-1);
 684                                 result = (-EIO);
 685                         }
 686                 } else {
 687                         if (STps->drv_block >= 0)
 688                                 STps->drv_block += blks;
 689                         STp->dirty = 0;
 690                         (STp->buffer)->buffer_bytes = 0;
 691                 }
 692                 st_release_request(SRpnt);
 693                 SRpnt = NULL;
 694         }
 695         return result;
 696 }
 697
 698
 699 /* Flush the tape buffer. The tape will be positioned correctly unless
 700    seek_next is true. */
 701 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 702 {
 703         int backspace, result;
 704         struct st_buffer *STbuffer;
 705         struct st_partstat *STps;
 706
 707         STbuffer = STp->buffer;
 708
 709         /*
 710          * If there was a bus reset, block further access
 711          * to this device.
 712          */
 713         if (STp->pos_unknown)
 714                 return (-EIO);
 715
 716         if (STp->ready != ST_READY)
 717                 return 0;
 718         STps = &(STp->ps[STp->partition]);
 719         if (STps->rw == ST_WRITING)     /* Writing */
 720                 return flush_write_buffer(STp);
 721
 722         if (STp->block_size == 0)
 723                 return 0;
 724
 725         backspace = ((STp->buffer)->buffer_bytes +
 726                      (STp->buffer)->read_pointer) / STp->block_size -
 727             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 728             STp->block_size;
 729         (STp->buffer)->buffer_bytes = 0;
 730         (STp->buffer)->read_pointer = 0;
 731         result = 0;
 732         if (!seek_next) {
 733                 if (STps->eof == ST_FM_HIT) {
 734                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 735                         if (!result)
 736                                 STps->eof = ST_NOEOF;
 737                         else {
 738                                 if (STps->drv_file >= 0)
 739                                         STps->drv_file++;
 740                                 STps->drv_block = 0;
 741                         }
 742                 }
 743                 if (!result && backspace > 0)
 744                         result = st_int_ioctl(STp, MTBSR, backspace);
 745         } else if (STps->eof == ST_FM_HIT) {
 746                 if (STps->drv_file >= 0)
 747                         STps->drv_file++;
 748                 STps->drv_block = 0;
 749                 STps->eof = ST_NOEOF;
 750         }
 751         return result;
 752
 753 }
 754 \f
 755 /* Set the mode parameters */
 756 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 757 {
 758         int set_it = 0;
 759         unsigned long arg;
 760         char *name = tape_name(STp);
 761
 762         if (!STp->density_changed &&
 763             STm->default_density >= 0 &&
 764             STm->default_density != STp->density) {
 765                 arg = STm->default_density;
 766                 set_it = 1;
 767         } else
 768                 arg = STp->density;
 769         arg <<= MT_ST_DENSITY_SHIFT;
 770         if (!STp->blksize_changed &&
 771             STm->default_blksize >= 0 &&
 772             STm->default_blksize != STp->block_size) {
 773                 arg |= STm->default_blksize;
 774                 set_it = 1;
 775         } else
 776                 arg |= STp->block_size;
 777         if (set_it &&
 778             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 779                 printk(KERN_WARNING
 780                        "%s: Can't set default block size to %d bytes and density %x.\n",
 781                        name, STm->default_blksize, STm->default_density);
 782                 if (modes_defined)
 783                         return (-EINVAL);
 784         }
 785         return 0;
 786 }
 787
 788
 789 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 790 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 791 {
 792         int retval, cmd;
 793         DEB(char *name = tape_name(STp);)
 794
 795
 796         cmd = do_lock ? SCSI_IOCTL_DOORLOCK : SCSI_IOCTL_DOORUNLOCK;
 797         DEBC(printk(ST_DEB_MSG "%s: %socking drive door.\n", name,
 798                     do_lock ? "L" : "Unl"));
 799         retval = scsi_ioctl(STp->device, cmd, NULL);
 800         if (!retval) {
 801                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 802         }
 803         else {
 804                 STp->door_locked = ST_LOCK_FAILS;
 805         }
 806         return retval;
 807 }
 808
 809
 810 /* Set the internal state after reset */
 811 static void reset_state(struct scsi_tape *STp)
 812 {
 813         int i;
 814         struct st_partstat *STps;
 815
 816         STp->pos_unknown = 0;
 817         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 818                 STps = &(STp->ps[i]);
 819                 STps->rw = ST_IDLE;
 820                 STps->eof = ST_NOEOF;
 821                 STps->at_sm = 0;
 822                 STps->last_block_valid = 0;
 823                 STps->drv_block = -1;
 824                 STps->drv_file = -1;
 825         }
 826         if (STp->can_partitions) {
 827                 STp->partition = find_partition(STp);
 828                 if (STp->partition < 0)
 829                         STp->partition = 0;
 830                 STp->new_partition = STp->partition;
 831         }
 832 }
 833 \f
 834 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 835    error code. */
 836 #define CHKRES_READY       0
 837 #define CHKRES_NEW_SESSION 1
 838 #define CHKRES_NOT_READY   2
 839 #define CHKRES_NO_TAPE     3
 840
 841 #define MAX_ATTENTIONS    10
 842
 843 static int test_ready(struct scsi_tape *STp, int do_wait)
 844 {
 845         int attentions, waits, max_wait, scode;
 846         int retval = CHKRES_READY, new_session = 0;
 847         unsigned char cmd[MAX_COMMAND_SIZE];
 848         struct st_request *SRpnt = NULL;
 849         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 850
 851         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 852
 853         for (attentions=waits=0; ; ) {
 854                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 855                 cmd[0] = TEST_UNIT_READY;
 856                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 857                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 858
 859                 if (!SRpnt) {
 860                         retval = (STp->buffer)->syscall_result;
 861                         break;
 862                 }
 863
 864                 if (cmdstatp->have_sense) {
 865
 866                         scode = cmdstatp->sense_hdr.sense_key;
 867
 868                         if (scode == UNIT_ATTENTION) { /* New media? */
 869                                 new_session = 1;
 870                                 if (attentions < MAX_ATTENTIONS) {
 871                                         attentions++;
 872                                         continue;
 873                                 }
 874                                 else {
 875                                         retval = (-EIO);
 876                                         break;
 877                                 }
 878                         }
 879
 880                         if (scode == NOT_READY) {
 881                                 if (waits < max_wait) {
 882                                         if (msleep_interruptible(1000)) {
 883                                                 retval = (-EINTR);
 884                                                 break;
 885                                         }
 886                                         waits++;
 887                                         continue;
 888                                 }
 889                                 else {
 890                                         if ((STp->device)->scsi_level >= SCSI_2 &&
 891                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
 892                                                 retval = CHKRES_NO_TAPE;
 893                                         else
 894                                                 retval = CHKRES_NOT_READY;
 895                                         break;
 896                                 }
 897                         }
 898                 }
 899
 900                 retval = (STp->buffer)->syscall_result;
 901                 if (!retval)
 902                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
 903                 break;
 904         }
 905
 906         if (SRpnt != NULL)
 907                 st_release_request(SRpnt);
 908         return retval;
 909 }
 910
 911
 912 /* See if the drive is ready and gather information about the tape. Return values:
 913    < 0   negative error code from errno.h
 914    0     drive ready
 915    1     drive not ready (possibly no tape)
 916 */
 917 static int check_tape(struct scsi_tape *STp, struct file *filp)
 918 {
 919         int i, retval, new_session = 0, do_wait;
 920         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
 921         unsigned short st_flags = filp->f_flags;
 922         struct st_request *SRpnt = NULL;
 923         struct st_modedef *STm;
 924         struct st_partstat *STps;
 925         char *name = tape_name(STp);
 926         struct inode *inode = filp->f_path.dentry->d_inode;
 927         int mode = TAPE_MODE(inode);
 928
 929         STp->ready = ST_READY;
 930
 931         if (mode != STp->current_mode) {
 932                 DEBC(printk(ST_DEB_MSG "%s: Mode change from %d to %d.\n",
 933                                name, STp->current_mode, mode));
 934                 new_session = 1;
 935                 STp->current_mode = mode;
 936         }
 937         STm = &(STp->modes[STp->current_mode]);
 938
 939         saved_cleaning = STp->cleaning_req;
 940         STp->cleaning_req = 0;
 941
 942         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
 943         retval = test_ready(STp, do_wait);
 944
 945         if (retval < 0)
 946             goto err_out;
 947
 948         if (retval == CHKRES_NEW_SESSION) {
 949                 STp->pos_unknown = 0;
 950                 STp->partition = STp->new_partition = 0;
 951                 if (STp->can_partitions)
 952                         STp->nbr_partitions = 1; /* This guess will be updated later
 953                                                     if necessary */
 954                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 955                         STps = &(STp->ps[i]);
 956                         STps->rw = ST_IDLE;
 957                         STps->eof = ST_NOEOF;
 958                         STps->at_sm = 0;
 959                         STps->last_block_valid = 0;
 960                         STps->drv_block = 0;
 961                         STps->drv_file = 0;
 962                 }
 963                 new_session = 1;
 964         }
 965         else {
 966                 STp->cleaning_req |= saved_cleaning;
 967
 968                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
 969                         if (retval == CHKRES_NO_TAPE)
 970                                 STp->ready = ST_NO_TAPE;
 971                         else
 972                                 STp->ready = ST_NOT_READY;
 973
 974                         STp->density = 0;       /* Clear the erroneous "residue" */
 975                         STp->write_prot = 0;
 976                         STp->block_size = 0;
 977                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
 978                         STp->partition = STp->new_partition = 0;
 979                         STp->door_locked = ST_UNLOCKED;
 980                         return CHKRES_NOT_READY;
 981                 }
 982         }
 983
 984         if (STp->omit_blklims)
 985                 STp->min_block = STp->max_block = (-1);
 986         else {
 987                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 988                 cmd[0] = READ_BLOCK_LIMITS;
 989
 990                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
 991                                    STp->device->timeout, MAX_READY_RETRIES, 1);
 992                 if (!SRpnt) {
 993                         retval = (STp->buffer)->syscall_result;
 994                         goto err_out;
 995                 }
 996
 997                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
 998                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
 999                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1000                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1001                             (STp->buffer)->b_data[5];
1002                         if ( DEB( debugging || ) !STp->inited)
1003                                 printk(KERN_INFO
1004                                        "%s: Block limits %d - %d bytes.\n", name,
1005                                        STp->min_block, STp->max_block);
1006                 } else {
1007                         STp->min_block = STp->max_block = (-1);
1008                         DEBC(printk(ST_DEB_MSG "%s: Can't read block limits.\n",
1009                                        name));
1010                 }
1011         }
1012
1013         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1014         cmd[0] = MODE_SENSE;
1015         cmd[4] = 12;
1016
1017         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1018                         STp->device->timeout, MAX_READY_RETRIES, 1);
1019         if (!SRpnt) {
1020                 retval = (STp->buffer)->syscall_result;
1021                 goto err_out;
1022         }
1023
1024         if ((STp->buffer)->syscall_result != 0) {
1025                 DEBC(printk(ST_DEB_MSG "%s: No Mode Sense.\n", name));
1026                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1027                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1028                 STp->drv_write_prot = 0;
1029         } else {
1030                 DEBC(printk(ST_DEB_MSG
1031                             "%s: Mode sense. Length %d, medium %x, WBS %x, BLL %d\n",
1032                             name,
1033                             (STp->buffer)->b_data[0], (STp->buffer)->b_data[1],
1034                             (STp->buffer)->b_data[2], (STp->buffer)->b_data[3]));
1035
1036                 if ((STp->buffer)->b_data[3] >= 8) {
1037                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1038                         STp->density = (STp->buffer)->b_data[4];
1039                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1040                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1041                         DEBC(printk(ST_DEB_MSG
1042                                     "%s: Density %x, tape length: %x, drv buffer: %d\n",
1043                                     name, STp->density, (STp->buffer)->b_data[5] * 65536 +
1044                                     (STp->buffer)->b_data[6] * 256 + (STp->buffer)->b_data[7],
1045                                     STp->drv_buffer));
1046                 }
1047                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1048         }
1049         st_release_request(SRpnt);
1050         SRpnt = NULL;
1051         STp->inited = 1;
1052
1053         if (STp->block_size > 0)
1054                 (STp->buffer)->buffer_blocks =
1055                         (STp->buffer)->buffer_size / STp->block_size;
1056         else
1057                 (STp->buffer)->buffer_blocks = 1;
1058         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1059
1060         DEBC(printk(ST_DEB_MSG
1061                        "%s: Block size: %d, buffer size: %d (%d blocks).\n", name,
1062                        STp->block_size, (STp->buffer)->buffer_size,
1063                        (STp->buffer)->buffer_blocks));
1064
1065         if (STp->drv_write_prot) {
1066                 STp->write_prot = 1;
1067
1068                 DEBC(printk(ST_DEB_MSG "%s: Write protected\n", name));
1069
1070                 if (do_wait &&
1071                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1072                      (st_flags & O_ACCMODE) == O_RDWR)) {
1073                         retval = (-EROFS);
1074                         goto err_out;
1075                 }
1076         }
1077
1078         if (STp->can_partitions && STp->nbr_partitions < 1) {
1079                 /* This code is reached when the device is opened for the first time
1080                    after the driver has been initialized with tape in the drive and the
1081                    partition support has been enabled. */
1082                 DEBC(printk(ST_DEB_MSG
1083                             "%s: Updating partition number in status.\n", name));
1084                 if ((STp->partition = find_partition(STp)) < 0) {
1085                         retval = STp->partition;
1086                         goto err_out;
1087                 }
1088                 STp->new_partition = STp->partition;
1089                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1090         }
1091
1092         if (new_session) {      /* Change the drive parameters for the new mode */
1093                 STp->density_changed = STp->blksize_changed = 0;
1094                 STp->compression_changed = 0;
1095                 if (!(STm->defaults_for_writes) &&
1096                     (retval = set_mode_densblk(STp, STm)) < 0)
1097                     goto err_out;
1098
1099                 if (STp->default_drvbuffer != 0xff) {
1100                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1101                                 printk(KERN_WARNING
1102                                        "%s: Can't set default drive buffering to %d.\n",
1103                                        name, STp->default_drvbuffer);
1104                 }
1105         }
1106
1107         return CHKRES_READY;
1108
1109  err_out:
1110         return retval;
1111 }
1112
1113
1114 \f/* Open the device. Needs to be called with BKL only because of incrementing the SCSI host
1115    module count. */
1116 static int st_open(struct inode *inode, struct file *filp)
1117 {
1118         int i, retval = (-EIO);
1119         struct scsi_tape *STp;
1120         struct st_partstat *STps;
1121         int dev = TAPE_NR(inode);
1122         char *name;
1123
1124         /*
1125          * We really want to do nonseekable_open(inode, filp); here, but some
1126          * versions of tar incorrectly call lseek on tapes and bail out if that
1127          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1128          */
1129         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1130
1131         if (!(STp = scsi_tape_get(dev)))
1132                 return -ENXIO;
1133
1134         write_lock(&st_dev_arr_lock);
1135         filp->private_data = STp;
1136         name = tape_name(STp);
1137
1138         if (STp->in_use) {
1139                 write_unlock(&st_dev_arr_lock);
1140                 scsi_tape_put(STp);
1141                 DEB( printk(ST_DEB_MSG "%s: Device already in use.\n", name); )
1142                 return (-EBUSY);
1143         }
1144
1145         STp->in_use = 1;
1146         write_unlock(&st_dev_arr_lock);
1147         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1148
1149         if (!scsi_block_when_processing_errors(STp->device)) {
1150                 retval = (-ENXIO);
1151                 goto err_out;
1152         }
1153
1154         /* See that we have at least a one page buffer available */
1155         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1156                 printk(KERN_WARNING "%s: Can't allocate one page tape buffer.\n",
1157                        name);
1158                 retval = (-EOVERFLOW);
1159                 goto err_out;
1160         }
1161
1162         (STp->buffer)->writing = 0;
1163         (STp->buffer)->syscall_result = 0;
1164
1165         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1166
1167         STp->dirty = 0;
1168         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1169                 STps = &(STp->ps[i]);
1170                 STps->rw = ST_IDLE;
1171         }
1172         STp->try_dio_now = STp->try_dio;
1173         STp->recover_count = 0;
1174         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1175              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = STp->nbr_combinable = 0; )
1176
1177         retval = check_tape(STp, filp);
1178         if (retval < 0)
1179                 goto err_out;
1180         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1181             retval != CHKRES_READY) {
1182                 if (STp->ready == NO_TAPE)
1183                         retval = (-ENOMEDIUM);
1184                 else
1185                         retval = (-EIO);
1186                 goto err_out;
1187         }
1188         return 0;
1189
1190  err_out:
1191         normalize_buffer(STp->buffer);
1192         STp->in_use = 0;
1193         scsi_tape_put(STp);
1194         return retval;
1195
1196 }
1197 \f
1198
1199 /* Flush the tape buffer before close */
1200 static int st_flush(struct file *filp, fl_owner_t id)
1201 {
1202         int result = 0, result2;
1203         unsigned char cmd[MAX_COMMAND_SIZE];
1204         struct st_request *SRpnt;
1205         struct scsi_tape *STp = filp->private_data;
1206         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1207         struct st_partstat *STps = &(STp->ps[STp->partition]);
1208         char *name = tape_name(STp);
1209
1210         if (file_count(filp) > 1)
1211                 return 0;
1212
1213         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1214                 result = flush_write_buffer(STp);
1215                 if (result != 0 && result != (-ENOSPC))
1216                         goto out;
1217         }
1218
1219         if (STp->can_partitions &&
1220             (result2 = switch_partition(STp)) < 0) {
1221                 DEBC(printk(ST_DEB_MSG
1222                                "%s: switch_partition at close failed.\n", name));
1223                 if (result == 0)
1224                         result = result2;
1225                 goto out;
1226         }
1227
1228         DEBC( if (STp->nbr_requests)
1229                 printk(KERN_DEBUG "%s: Number of r/w requests %d, dio used in %d, pages %d (%d).\n",
1230                        name, STp->nbr_requests, STp->nbr_dio, STp->nbr_pages, STp->nbr_combinable));
1231
1232         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1233                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1234
1235                 DEBC(printk(ST_DEB_MSG "%s: Async write waits %d, finished %d.\n",
1236                             name, STp->nbr_waits, STp->nbr_finished);
1237                 )
1238
1239                 memset(cmd, 0, MAX_COMMAND_SIZE);
1240                 cmd[0] = WRITE_FILEMARKS;
1241                 cmd[4] = 1 + STp->two_fm;
1242
1243                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1244                                    STp->device->timeout, MAX_WRITE_RETRIES, 1);
1245                 if (!SRpnt) {
1246                         result = (STp->buffer)->syscall_result;
1247                         goto out;
1248                 }
1249
1250                 if (STp->buffer->syscall_result == 0 ||
1251                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1252                      (cmdstatp->flags & SENSE_EOM) &&
1253                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1254                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1255                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1256                         /* Write successful at EOM */
1257                         st_release_request(SRpnt);
1258                         SRpnt = NULL;
1259                         if (STps->drv_file >= 0)
1260                                 STps->drv_file++;
1261                         STps->drv_block = 0;
1262                         if (STp->two_fm)
1263                                 cross_eof(STp, 0);
1264                         STps->eof = ST_FM;
1265                 }
1266                 else { /* Write error */
1267                         st_release_request(SRpnt);
1268                         SRpnt = NULL;
1269                         printk(KERN_ERR "%s: Error on write filemark.\n", name);
1270                         if (result == 0)
1271                                 result = (-EIO);
1272                 }
1273
1274                 DEBC(printk(ST_DEB_MSG "%s: Buffer flushed, %d EOF(s) written\n",
1275                             name, cmd[4]));
1276         } else if (!STp->rew_at_close) {
1277                 STps = &(STp->ps[STp->partition]);
1278                 if (!STm->sysv || STps->rw != ST_READING) {
1279                         if (STp->can_bsr)
1280                                 result = flush_buffer(STp, 0);
1281                         else if (STps->eof == ST_FM_HIT) {
1282                                 result = cross_eof(STp, 0);
1283                                 if (result) {
1284                                         if (STps->drv_file >= 0)
1285                                                 STps->drv_file++;
1286                                         STps->drv_block = 0;
1287                                         STps->eof = ST_FM;
1288                                 } else
1289                                         STps->eof = ST_NOEOF;
1290                         }
1291                 } else if ((STps->eof == ST_NOEOF &&
1292                             !(result = cross_eof(STp, 1))) ||
1293                            STps->eof == ST_FM_HIT) {
1294                         if (STps->drv_file >= 0)
1295                                 STps->drv_file++;
1296                         STps->drv_block = 0;
1297                         STps->eof = ST_FM;
1298                 }
1299         }
1300
1301       out:
1302         if (STp->rew_at_close) {
1303                 result2 = st_int_ioctl(STp, MTREW, 1);
1304                 if (result == 0)
1305                         result = result2;
1306         }
1307         return result;
1308 }
1309
1310
1311 /* Close the device and release it. BKL is not needed: this is the only thread
1312    accessing this tape. */
1313 static int st_release(struct inode *inode, struct file *filp)
1314 {
1315         int result = 0;
1316         struct scsi_tape *STp = filp->private_data;
1317
1318         if (STp->door_locked == ST_LOCKED_AUTO)
1319                 do_door_lock(STp, 0);
1320
1321         normalize_buffer(STp->buffer);
1322         write_lock(&st_dev_arr_lock);
1323         STp->in_use = 0;
1324         write_unlock(&st_dev_arr_lock);
1325         scsi_tape_put(STp);
1326
1327         return result;
1328 }
1329 \f
1330 /* The checks common to both reading and writing */
1331 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1332 {
1333         ssize_t retval = 0;
1334
1335         /*
1336          * If we are in the middle of error recovery, don't let anyone
1337          * else try and use this device.  Also, if error recovery fails, it
1338          * may try and take the device offline, in which case all further
1339          * access to the device is prohibited.
1340          */
1341         if (!scsi_block_when_processing_errors(STp->device)) {
1342                 retval = (-ENXIO);
1343                 goto out;
1344         }
1345
1346         if (STp->ready != ST_READY) {
1347                 if (STp->ready == ST_NO_TAPE)
1348                         retval = (-ENOMEDIUM);
1349                 else
1350                         retval = (-EIO);
1351                 goto out;
1352         }
1353
1354         if (! STp->modes[STp->current_mode].defined) {
1355                 retval = (-ENXIO);
1356                 goto out;
1357         }
1358
1359
1360         /*
1361          * If there was a bus reset, block further access
1362          * to this device.
1363          */
1364         if (STp->pos_unknown) {
1365                 retval = (-EIO);
1366                 goto out;
1367         }
1368
1369         if (count == 0)
1370                 goto out;
1371
1372         DEB(
1373         if (!STp->in_use) {
1374                 printk(ST_DEB_MSG "%s: Incorrect device.\n", tape_name(STp));
1375                 retval = (-EIO);
1376                 goto out;
1377         } ) /* end DEB */
1378
1379         if (STp->can_partitions &&
1380             (retval = switch_partition(STp)) < 0)
1381                 goto out;
1382
1383         if (STp->block_size == 0 && STp->max_block > 0 &&
1384             (count < STp->min_block || count > STp->max_block)) {
1385                 retval = (-EINVAL);
1386                 goto out;
1387         }
1388
1389         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1390             !do_door_lock(STp, 1))
1391                 STp->door_locked = ST_LOCKED_AUTO;
1392
1393  out:
1394         return retval;
1395 }
1396
1397
1398 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1399                            size_t count, int is_read)
1400 {
1401         int i, bufsize, retval = 0;
1402         struct st_buffer *STbp = STp->buffer;
1403
1404         if (is_read)
1405                 i = STp->try_dio_now && try_rdio;
1406         else
1407                 i = STp->try_dio_now && try_wdio;
1408
1409         if (i && ((unsigned long)buf & queue_dma_alignment(
1410                                         STp->device->request_queue)) == 0) {
1411                 i = sgl_map_user_pages(&(STbp->sg[0]), STbp->use_sg,
1412                                       (unsigned long)buf, count, (is_read ? READ : WRITE));
1413                 if (i > 0) {
1414                         STbp->do_dio = i;
1415                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1416                 }
1417                 else
1418                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1419                 STbp->sg_segs = STbp->do_dio;
1420                 STbp->frp_sg_current = 0;
1421                 DEB(
1422                      if (STbp->do_dio) {
1423                         STp->nbr_dio++;
1424                         STp->nbr_pages += STbp->do_dio;
1425                         for (i=1; i < STbp->do_dio; i++)
1426                                 if (page_to_pfn(STbp->sg[i].page) == page_to_pfn(STbp->sg[i-1].page) + 1)
1427                                         STp->nbr_combinable++;
1428                      }
1429                 )
1430         } else
1431                 STbp->do_dio = 0;
1432         DEB( STp->nbr_requests++; )
1433
1434         if (!STbp->do_dio) {
1435                 if (STp->block_size)
1436                         bufsize = STp->block_size > st_fixed_buffer_size ?
1437                                 STp->block_size : st_fixed_buffer_size;
1438                 else
1439                         bufsize = count;
1440                 if (bufsize > STbp->buffer_size &&
1441                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1442                         printk(KERN_WARNING "%s: Can't allocate %d byte tape buffer.\n",
1443                                tape_name(STp), bufsize);
1444                         retval = (-EOVERFLOW);
1445                         goto out;
1446                 }
1447                 if (STp->block_size)
1448                         STbp->buffer_blocks = bufsize / STp->block_size;
1449         }
1450
1451  out:
1452         return retval;
1453 }
1454
1455
1456 /* Can be called more than once after each setup_buffer() */
1457 static void release_buffering(struct scsi_tape *STp, int is_read)
1458 {
1459         struct st_buffer *STbp;
1460
1461         STbp = STp->buffer;
1462         if (STbp->do_dio) {
1463                 sgl_unmap_user_pages(&(STbp->sg[0]), STbp->do_dio, is_read);
1464                 STbp->do_dio = 0;
1465                 STbp->sg_segs = 0;
1466         }
1467 }
1468
1469
1470 /* Write command */
1471 static ssize_t
1472 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1473 {
1474         ssize_t total;
1475         ssize_t i, do_count, blks, transfer;
1476         ssize_t retval;
1477         int undone, retry_eot = 0, scode;
1478         int async_write;
1479         unsigned char cmd[MAX_COMMAND_SIZE];
1480         const char __user *b_point;
1481         struct st_request *SRpnt = NULL;
1482         struct scsi_tape *STp = filp->private_data;
1483         struct st_modedef *STm;
1484         struct st_partstat *STps;
1485         struct st_buffer *STbp;
1486         char *name = tape_name(STp);
1487
1488         if (down_interruptible(&STp->lock))
1489                 return -ERESTARTSYS;
1490
1491         retval = rw_checks(STp, filp, count);
1492         if (retval || count == 0)
1493                 goto out;
1494
1495         /* Write must be integral number of blocks */
1496         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1497                 printk(KERN_WARNING "%s: Write not multiple of tape block size.\n",
1498                        name);
1499                 retval = (-EINVAL);
1500                 goto out;
1501         }
1502
1503         STm = &(STp->modes[STp->current_mode]);
1504         STps = &(STp->ps[STp->partition]);
1505
1506         if (STp->write_prot) {
1507                 retval = (-EACCES);
1508                 goto out;
1509         }
1510
1511
1512         if (STps->rw == ST_READING) {
1513                 retval = flush_buffer(STp, 0);
1514                 if (retval)
1515                         goto out;
1516                 STps->rw = ST_WRITING;
1517         } else if (STps->rw != ST_WRITING &&
1518                    STps->drv_file == 0 && STps->drv_block == 0) {
1519                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1520                         goto out;
1521                 if (STm->default_compression != ST_DONT_TOUCH &&
1522                     !(STp->compression_changed)) {
1523                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1524                                 printk(KERN_WARNING "%s: Can't set default compression.\n",
1525                                        name);
1526                                 if (modes_defined) {
1527                                         retval = (-EINVAL);
1528                                         goto out;
1529                                 }
1530                         }
1531                 }
1532         }
1533
1534         STbp = STp->buffer;
1535         i = write_behind_check(STp);
1536         if (i) {
1537                 if (i == -ENOSPC)
1538                         STps->eof = ST_EOM_OK;
1539                 else
1540                         STps->eof = ST_EOM_ERROR;
1541         }
1542
1543         if (STps->eof == ST_EOM_OK) {
1544                 STps->eof = ST_EOD_1;  /* allow next write */
1545                 retval = (-ENOSPC);
1546                 goto out;
1547         }
1548         else if (STps->eof == ST_EOM_ERROR) {
1549                 retval = (-EIO);
1550                 goto out;
1551         }
1552
1553         /* Check the buffer readability in cases where copy_user might catch
1554            the problems after some tape movement. */
1555         if (STp->block_size != 0 &&
1556             !STbp->do_dio &&
1557             (copy_from_user(&i, buf, 1) != 0 ||
1558              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1559                 retval = (-EFAULT);
1560                 goto out;
1561         }
1562
1563         retval = setup_buffering(STp, buf, count, 0);
1564         if (retval)
1565                 goto out;
1566
1567         total = count;
1568
1569         memset(cmd, 0, MAX_COMMAND_SIZE);
1570         cmd[0] = WRITE_6;
1571         cmd[1] = (STp->block_size != 0);
1572
1573         STps->rw = ST_WRITING;
1574
1575         b_point = buf;
1576         while (count > 0 && !retry_eot) {
1577
1578                 if (STbp->do_dio) {
1579                         do_count = count;
1580                 }
1581                 else {
1582                         if (STp->block_size == 0)
1583                                 do_count = count;
1584                         else {
1585                                 do_count = STbp->buffer_blocks * STp->block_size -
1586                                         STbp->buffer_bytes;
1587                                 if (do_count > count)
1588                                         do_count = count;
1589                         }
1590
1591                         i = append_to_buffer(b_point, STbp, do_count);
1592                         if (i) {
1593                                 retval = i;
1594                                 goto out;
1595                         }
1596                 }
1597                 count -= do_count;
1598                 b_point += do_count;
1599
1600                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1601                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1602
1603                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1604                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1605                     STbp->buffer_bytes < STbp->buffer_size) {
1606                         STp->dirty = 1;
1607                         /* Don't write a buffer that is not full enough. */
1608                         if (!async_write && count == 0)
1609                                 break;
1610                 }
1611
1612         retry_write:
1613                 if (STp->block_size == 0)
1614                         blks = transfer = do_count;
1615                 else {
1616                         if (!STbp->do_dio)
1617                                 blks = STbp->buffer_bytes;
1618                         else
1619                                 blks = do_count;
1620                         blks /= STp->block_size;
1621                         transfer = blks * STp->block_size;
1622                 }
1623                 cmd[2] = blks >> 16;
1624                 cmd[3] = blks >> 8;
1625                 cmd[4] = blks;
1626
1627                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1628                                    STp->device->timeout, MAX_WRITE_RETRIES, !async_write);
1629                 if (!SRpnt) {
1630                         retval = STbp->syscall_result;
1631                         goto out;
1632                 }
1633                 if (async_write && !STbp->syscall_result) {
1634                         STbp->writing = transfer;
1635                         STp->dirty = !(STbp->writing ==
1636                                        STbp->buffer_bytes);
1637                         SRpnt = NULL;  /* Prevent releasing this request! */
1638                         DEB( STp->write_pending = 1; )
1639                         break;
1640                 }
1641
1642                 if (STbp->syscall_result != 0) {
1643                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1644
1645                         DEBC(printk(ST_DEB_MSG "%s: Error on write:\n", name));
1646                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1647                                 scode = cmdstatp->sense_hdr.sense_key;
1648                                 if (cmdstatp->remainder_valid)
1649                                         undone = (int)cmdstatp->uremainder64;
1650                                 else if (STp->block_size == 0 &&
1651                                          scode == VOLUME_OVERFLOW)
1652                                         undone = transfer;
1653                                 else
1654                                         undone = 0;
1655                                 if (STp->block_size != 0)
1656                                         undone *= STp->block_size;
1657                                 if (undone <= do_count) {
1658                                         /* Only data from this write is not written */
1659                                         count += undone;
1660                                         do_count -= undone;
1661                                         if (STp->block_size)
1662                                                 blks = (transfer - undone) / STp->block_size;
1663                                         STps->eof = ST_EOM_OK;
1664                                         /* Continue in fixed block mode if all written
1665                                            in this request but still something left to write
1666                                            (retval left to zero)
1667                                         */
1668                                         if (STp->block_size == 0 ||
1669                                             undone > 0 || count == 0)
1670                                                 retval = (-ENOSPC); /* EOM within current request */
1671                                         DEBC(printk(ST_DEB_MSG
1672                                                        "%s: EOM with %d bytes unwritten.\n",
1673                                                        name, (int)count));
1674                                 } else {
1675                                         /* EOT within data buffered earlier (possible only
1676                                            in fixed block mode without direct i/o) */
1677                                         if (!retry_eot && !cmdstatp->deferred &&
1678                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1679                                                 move_buffer_data(STp->buffer, transfer - undone);
1680                                                 retry_eot = 1;
1681                                                 if (STps->drv_block >= 0) {
1682                                                         STps->drv_block += (transfer - undone) /
1683                                                                 STp->block_size;
1684                                                 }
1685                                                 STps->eof = ST_EOM_OK;
1686                                                 DEBC(printk(ST_DEB_MSG
1687                                                             "%s: Retry write of %d bytes at EOM.\n",
1688                                                             name, STp->buffer->buffer_bytes));
1689                                                 goto retry_write;
1690                                         }
1691                                         else {
1692                                                 /* Either error within data buffered by driver or
1693                                                    failed retry */
1694                                                 count -= do_count;
1695                                                 blks = do_count = 0;
1696                                                 STps->eof = ST_EOM_ERROR;
1697                                                 STps->drv_block = (-1); /* Too cautious? */
1698                                                 retval = (-EIO);        /* EOM for old data */
1699                                                 DEBC(printk(ST_DEB_MSG
1700                                                             "%s: EOM with lost data.\n",
1701                                                             name));
1702                                         }
1703                                 }
1704                         } else {
1705                                 count += do_count;
1706                                 STps->drv_block = (-1);         /* Too cautious? */
1707                                 retval = STbp->syscall_result;
1708                         }
1709
1710                 }
1711
1712                 if (STps->drv_block >= 0) {
1713                         if (STp->block_size == 0)
1714                                 STps->drv_block += (do_count > 0);
1715                         else
1716                                 STps->drv_block += blks;
1717                 }
1718
1719                 STbp->buffer_bytes = 0;
1720                 STp->dirty = 0;
1721
1722                 if (retval || retry_eot) {
1723                         if (count < total)
1724                                 retval = total - count;
1725                         goto out;
1726                 }
1727         }
1728
1729         if (STps->eof == ST_EOD_1)
1730                 STps->eof = ST_EOM_OK;
1731         else if (STps->eof != ST_EOM_OK)
1732                 STps->eof = ST_NOEOF;
1733         retval = total - count;
1734
1735  out:
1736         if (SRpnt != NULL)
1737                 st_release_request(SRpnt);
1738         release_buffering(STp, 0);
1739         up(&STp->lock);
1740
1741         return retval;
1742 }
1743 \f
1744 /* Read data from the tape. Returns zero in the normal case, one if the
1745    eof status has changed, and the negative error code in case of a
1746    fatal error. Otherwise updates the buffer and the eof state.
1747
1748    Does release user buffer mapping if it is set.
1749 */
1750 static long read_tape(struct scsi_tape *STp, long count,
1751                       struct st_request ** aSRpnt)
1752 {
1753         int transfer, blks, bytes;
1754         unsigned char cmd[MAX_COMMAND_SIZE];
1755         struct st_request *SRpnt;
1756         struct st_modedef *STm;
1757         struct st_partstat *STps;
1758         struct st_buffer *STbp;
1759         int retval = 0;
1760         char *name = tape_name(STp);
1761
1762         if (count == 0)
1763                 return 0;
1764
1765         STm = &(STp->modes[STp->current_mode]);
1766         STps = &(STp->ps[STp->partition]);
1767         if (STps->eof == ST_FM_HIT)
1768                 return 1;
1769         STbp = STp->buffer;
1770
1771         if (STp->block_size == 0)
1772                 blks = bytes = count;
1773         else {
1774                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1775                         blks = (STp->buffer)->buffer_blocks;
1776                         bytes = blks * STp->block_size;
1777                 } else {
1778                         bytes = count;
1779                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1780                                 bytes = (STp->buffer)->buffer_size;
1781                         blks = bytes / STp->block_size;
1782                         bytes = blks * STp->block_size;
1783                 }
1784         }
1785
1786         memset(cmd, 0, MAX_COMMAND_SIZE);
1787         cmd[0] = READ_6;
1788         cmd[1] = (STp->block_size != 0);
1789         cmd[2] = blks >> 16;
1790         cmd[3] = blks >> 8;
1791         cmd[4] = blks;
1792
1793         SRpnt = *aSRpnt;
1794         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1795                            STp->device->timeout, MAX_RETRIES, 1);
1796         release_buffering(STp, 1);
1797         *aSRpnt = SRpnt;
1798         if (!SRpnt)
1799                 return STbp->syscall_result;
1800
1801         STbp->read_pointer = 0;
1802         STps->at_sm = 0;
1803
1804         /* Something to check */
1805         if (STbp->syscall_result) {
1806                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1807
1808                 retval = 1;
1809                 DEBC(printk(ST_DEB_MSG "%s: Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1810                             name,
1811                             SRpnt->sense[0], SRpnt->sense[1],
1812                             SRpnt->sense[2], SRpnt->sense[3],
1813                             SRpnt->sense[4], SRpnt->sense[5],
1814                             SRpnt->sense[6], SRpnt->sense[7]));
1815                 if (cmdstatp->have_sense) {
1816
1817                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1818                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1819
1820                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1821                                 /* Compute the residual count */
1822                                 if (cmdstatp->remainder_valid)
1823                                         transfer = (int)cmdstatp->uremainder64;
1824                                 else
1825                                         transfer = 0;
1826                                 if (STp->block_size == 0 &&
1827                                     cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR)
1828                                         transfer = bytes;
1829
1830                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1831                                         if (STp->block_size == 0) {
1832                                                 if (transfer <= 0) {
1833                                                         if (transfer < 0)
1834                                                                 printk(KERN_NOTICE
1835                                                                        "%s: Failed to read %d byte block with %d byte transfer.\n",
1836                                                                        name, bytes - transfer, bytes);
1837                                                         if (STps->drv_block >= 0)
1838                                                                 STps->drv_block += 1;
1839                                                         STbp->buffer_bytes = 0;
1840                                                         return (-ENOMEM);
1841                                                 }
1842                                                 STbp->buffer_bytes = bytes - transfer;
1843                                         } else {
1844                                                 st_release_request(SRpnt);
1845                                                 SRpnt = *aSRpnt = NULL;
1846                                                 if (transfer == blks) { /* We did not get anything, error */
1847                                                         printk(KERN_NOTICE "%s: Incorrect block size.\n", name);
1848                                                         if (STps->drv_block >= 0)
1849                                                                 STps->drv_block += blks - transfer + 1;
1850                                                         st_int_ioctl(STp, MTBSR, 1);
1851                                                         return (-EIO);
1852                                                 }
1853                                                 /* We have some data, deliver it */
1854                                                 STbp->buffer_bytes = (blks - transfer) *
1855                                                     STp->block_size;
1856                                                 DEBC(printk(ST_DEB_MSG
1857                                                             "%s: ILI but enough data received %ld %d.\n",
1858                                                             name, count, STbp->buffer_bytes));
1859                                                 if (STps->drv_block >= 0)
1860                                                         STps->drv_block += 1;
1861                                                 if (st_int_ioctl(STp, MTBSR, 1))
1862                                                         return (-EIO);
1863                                         }
1864                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
1865                                         if (STps->eof != ST_FM_HIT)
1866                                                 STps->eof = ST_FM_HIT;
1867                                         else
1868                                                 STps->eof = ST_EOD_2;
1869                                         if (STp->block_size == 0)
1870                                                 STbp->buffer_bytes = 0;
1871                                         else
1872                                                 STbp->buffer_bytes =
1873                                                     bytes - transfer * STp->block_size;
1874                                         DEBC(printk(ST_DEB_MSG
1875                                                     "%s: EOF detected (%d bytes read).\n",
1876                                                     name, STbp->buffer_bytes));
1877                                 } else if (cmdstatp->flags & SENSE_EOM) {
1878                                         if (STps->eof == ST_FM)
1879                                                 STps->eof = ST_EOD_1;
1880                                         else
1881                                                 STps->eof = ST_EOM_OK;
1882                                         if (STp->block_size == 0)
1883                                                 STbp->buffer_bytes = bytes - transfer;
1884                                         else
1885                                                 STbp->buffer_bytes =
1886                                                     bytes - transfer * STp->block_size;
1887
1888                                         DEBC(printk(ST_DEB_MSG "%s: EOM detected (%d bytes read).\n",
1889                                                     name, STbp->buffer_bytes));
1890                                 }
1891                         }
1892                         /* end of EOF, EOM, ILI test */
1893                         else {  /* nonzero sense key */
1894                                 DEBC(printk(ST_DEB_MSG
1895                                             "%s: Tape error while reading.\n", name));
1896                                 STps->drv_block = (-1);
1897                                 if (STps->eof == ST_FM &&
1898                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
1899                                         DEBC(printk(ST_DEB_MSG
1900                                                     "%s: Zero returned for first BLANK CHECK after EOF.\n",
1901                                                     name));
1902                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
1903                                 } else  /* Some other extended sense code */
1904                                         retval = (-EIO);
1905                         }
1906
1907                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
1908                                 STbp->buffer_bytes = 0;
1909                 }
1910                 /* End of extended sense test */
1911                 else {          /* Non-extended sense */
1912                         retval = STbp->syscall_result;
1913                 }
1914
1915         }
1916         /* End of error handling */
1917         else                    /* Read successful */
1918                 STbp->buffer_bytes = bytes;
1919
1920         if (STps->drv_block >= 0) {
1921                 if (STp->block_size == 0)
1922                         STps->drv_block++;
1923                 else
1924                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
1925         }
1926         return retval;
1927 }
1928 \f
1929
1930 /* Read command */
1931 static ssize_t
1932 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
1933 {
1934         ssize_t total;
1935         ssize_t retval = 0;
1936         ssize_t i, transfer;
1937         int special, do_dio = 0;
1938         struct st_request *SRpnt = NULL;
1939         struct scsi_tape *STp = filp->private_data;
1940         struct st_modedef *STm;
1941         struct st_partstat *STps;
1942         struct st_buffer *STbp = STp->buffer;
1943         DEB( char *name = tape_name(STp); )
1944
1945         if (down_interruptible(&STp->lock))
1946                 return -ERESTARTSYS;
1947
1948         retval = rw_checks(STp, filp, count);
1949         if (retval || count == 0)
1950                 goto out;
1951
1952         STm = &(STp->modes[STp->current_mode]);
1953         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1954                 if (!STm->do_read_ahead) {
1955                         retval = (-EINVAL);     /* Read must be integral number of blocks */
1956                         goto out;
1957                 }
1958                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
1959         }
1960
1961         STps = &(STp->ps[STp->partition]);
1962         if (STps->rw == ST_WRITING) {
1963                 retval = flush_buffer(STp, 0);
1964                 if (retval)
1965                         goto out;
1966                 STps->rw = ST_READING;
1967         }
1968         DEB(
1969         if (debugging && STps->eof != ST_NOEOF)
1970                 printk(ST_DEB_MSG "%s: EOF/EOM flag up (%d). Bytes %d\n", name,
1971                        STps->eof, STbp->buffer_bytes);
1972         ) /* end DEB */
1973
1974         retval = setup_buffering(STp, buf, count, 1);
1975         if (retval)
1976                 goto out;
1977         do_dio = STbp->do_dio;
1978
1979         if (STbp->buffer_bytes == 0 &&
1980             STps->eof >= ST_EOD_1) {
1981                 if (STps->eof < ST_EOD) {
1982                         STps->eof += 1;
1983                         retval = 0;
1984                         goto out;
1985                 }
1986                 retval = (-EIO);        /* EOM or Blank Check */
1987                 goto out;
1988         }
1989
1990         if (do_dio) {
1991                 /* Check the buffer writability before any tape movement. Don't alter
1992                    buffer data. */
1993                 if (copy_from_user(&i, buf, 1) != 0 ||
1994                     copy_to_user(buf, &i, 1) != 0 ||
1995                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
1996                     copy_to_user(buf + count - 1, &i, 1) != 0) {
1997                         retval = (-EFAULT);
1998                         goto out;
1999                 }
2000         }
2001
2002         STps->rw = ST_READING;
2003
2004
2005         /* Loop until enough data in buffer or a special condition found */
2006         for (total = 0, special = 0; total < count && !special;) {
2007
2008                 /* Get new data if the buffer is empty */
2009                 if (STbp->buffer_bytes == 0) {
2010                         special = read_tape(STp, count - total, &SRpnt);
2011                         if (special < 0) {      /* No need to continue read */
2012                                 retval = special;
2013                                 goto out;
2014                         }
2015                 }
2016
2017                 /* Move the data from driver buffer to user buffer */
2018                 if (STbp->buffer_bytes > 0) {
2019                         DEB(
2020                         if (debugging && STps->eof != ST_NOEOF)
2021                                 printk(ST_DEB_MSG
2022                                        "%s: EOF up (%d). Left %d, needed %d.\n", name,
2023                                        STps->eof, STbp->buffer_bytes,
2024                                        (int)(count - total));
2025                         ) /* end DEB */
2026                         transfer = STbp->buffer_bytes < count - total ?
2027                             STbp->buffer_bytes : count - total;
2028                         if (!do_dio) {
2029                                 i = from_buffer(STbp, buf, transfer);
2030                                 if (i) {
2031                                         retval = i;
2032                                         goto out;
2033                                 }
2034                         }
2035                         buf += transfer;
2036                         total += transfer;
2037                 }
2038
2039                 if (STp->block_size == 0)
2040                         break;  /* Read only one variable length block */
2041
2042         }                       /* for (total = 0, special = 0;
2043                                    total < count && !special; ) */
2044
2045         /* Change the eof state if no data from tape or buffer */
2046         if (total == 0) {
2047                 if (STps->eof == ST_FM_HIT) {
2048                         STps->eof = ST_FM;
2049                         STps->drv_block = 0;
2050                         if (STps->drv_file >= 0)
2051                                 STps->drv_file++;
2052                 } else if (STps->eof == ST_EOD_1) {
2053                         STps->eof = ST_EOD_2;
2054                         STps->drv_block = 0;
2055                         if (STps->drv_file >= 0)
2056                                 STps->drv_file++;
2057                 } else if (STps->eof == ST_EOD_2)
2058                         STps->eof = ST_EOD;
2059         } else if (STps->eof == ST_FM)
2060                 STps->eof = ST_NOEOF;
2061         retval = total;
2062
2063  out:
2064         if (SRpnt != NULL) {
2065                 st_release_request(SRpnt);
2066                 SRpnt = NULL;
2067         }
2068         if (do_dio) {
2069                 release_buffering(STp, 1);
2070                 STbp->buffer_bytes = 0;
2071         }
2072         up(&STp->lock);
2073
2074         return retval;
2075 }
2076 \f
2077
2078
2079 DEB(
2080 /* Set the driver options */
2081 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm, char *name)
2082 {
2083         if (debugging) {
2084                 printk(KERN_INFO
2085                        "%s: Mode %d options: buffer writes: %d, async writes: %d, read ahead: %d\n",
2086                        name, STp->current_mode, STm->do_buffer_writes, STm->do_async_writes,
2087                        STm->do_read_ahead);
2088                 printk(KERN_INFO
2089                        "%s:    can bsr: %d, two FMs: %d, fast mteom: %d, auto lock: %d,\n",
2090                        name, STp->can_bsr, STp->two_fm, STp->fast_mteom, STp->do_auto_lock);
2091                 printk(KERN_INFO
2092                        "%s:    defs for wr: %d, no block limits: %d, partitions: %d, s2 log: %d\n",
2093                        name, STm->defaults_for_writes, STp->omit_blklims, STp->can_partitions,
2094                        STp->scsi2_logical);
2095                 printk(KERN_INFO
2096                        "%s:    sysv: %d nowait: %d\n", name, STm->sysv, STp->immediate);
2097                 printk(KERN_INFO "%s:    debugging: %d\n",
2098                        name, debugging);
2099         }
2100 }
2101         )
2102
2103
2104 static int st_set_options(struct scsi_tape *STp, long options)
2105 {
2106         int value;
2107         long code;
2108         struct st_modedef *STm;
2109         char *name = tape_name(STp);
2110         struct cdev *cd0, *cd1;
2111
2112         STm = &(STp->modes[STp->current_mode]);
2113         if (!STm->defined) {
2114                 cd0 = STm->cdevs[0]; cd1 = STm->cdevs[1];
2115                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2116                 STm->cdevs[0] = cd0; STm->cdevs[1] = cd1;
2117                 modes_defined = 1;
2118                 DEBC(printk(ST_DEB_MSG
2119                             "%s: Initialized mode %d definition from mode 0\n",
2120                             name, STp->current_mode));
2121         }
2122
2123         code = options & MT_ST_OPTIONS;
2124         if (code == MT_ST_BOOLEANS) {
2125                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2126                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2127                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2128                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2129                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2130                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2131                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2132                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2133                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2134                 if ((STp->device)->scsi_level >= SCSI_2)
2135                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2136                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2137                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2138                 STm->sysv = (options & MT_ST_SYSV) != 0;
2139                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2140                      st_log_options(STp, STm, name); )
2141         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2142                 value = (code == MT_ST_SETBOOLEANS);
2143                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2144                         STm->do_buffer_writes = value;
2145                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2146                         STm->do_async_writes = value;
2147                 if ((options & MT_ST_DEF_WRITES) != 0)
2148                         STm->defaults_for_writes = value;
2149                 if ((options & MT_ST_READ_AHEAD) != 0)
2150                         STm->do_read_ahead = value;
2151                 if ((options & MT_ST_TWO_FM) != 0)
2152                         STp->two_fm = value;
2153                 if ((options & MT_ST_FAST_MTEOM) != 0)
2154                         STp->fast_mteom = value;
2155                 if ((options & MT_ST_AUTO_LOCK) != 0)
2156                         STp->do_auto_lock = value;
2157                 if ((options & MT_ST_CAN_BSR) != 0)
2158                         STp->can_bsr = value;
2159                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2160                         STp->omit_blklims = value;
2161                 if ((STp->device)->scsi_level >= SCSI_2 &&
2162                     (options & MT_ST_CAN_PARTITIONS) != 0)
2163                         STp->can_partitions = value;
2164                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2165                         STp->scsi2_logical = value;
2166                 if ((options & MT_ST_NOWAIT) != 0)
2167                         STp->immediate = value;
2168                 if ((options & MT_ST_SYSV) != 0)
2169                         STm->sysv = value;
2170                 DEB(
2171                 if ((options & MT_ST_DEBUGGING) != 0)
2172                         debugging = value;
2173                         st_log_options(STp, STm, name); )
2174         } else if (code == MT_ST_WRITE_THRESHOLD) {
2175                 /* Retained for compatibility */
2176         } else if (code == MT_ST_DEF_BLKSIZE) {
2177                 value = (options & ~MT_ST_OPTIONS);
2178                 if (value == ~MT_ST_OPTIONS) {
2179                         STm->default_blksize = (-1);
2180                         DEBC( printk(KERN_INFO "%s: Default block size disabled.\n", name));
2181                 } else {
2182                         STm->default_blksize = value;
2183                         DEBC( printk(KERN_INFO "%s: Default block size set to %d bytes.\n",
2184                                name, STm->default_blksize));
2185                         if (STp->ready == ST_READY) {
2186                                 STp->blksize_changed = 0;
2187                                 set_mode_densblk(STp, STm);
2188                         }
2189                 }
2190         } else if (code == MT_ST_TIMEOUTS) {
2191                 value = (options & ~MT_ST_OPTIONS);
2192                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2193                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2194                         DEBC( printk(KERN_INFO "%s: Long timeout set to %d seconds.\n", name,
2195                                (value & ~MT_ST_SET_LONG_TIMEOUT)));
2196                 } else {
2197                         STp->device->timeout = value * HZ;
2198                         DEBC( printk(KERN_INFO "%s: Normal timeout set to %d seconds.\n",
2199                                 name, value) );
2200                 }
2201         } else if (code == MT_ST_SET_CLN) {
2202                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2203                 if (value != 0 &&
2204                     value < EXTENDED_SENSE_START && value >= SCSI_SENSE_BUFFERSIZE)
2205                         return (-EINVAL);
2206                 STp->cln_mode = value;
2207                 STp->cln_sense_mask = (options >> 8) & 0xff;
2208                 STp->cln_sense_value = (options >> 16) & 0xff;
2209                 printk(KERN_INFO
2210                        "%s: Cleaning request mode %d, mask %02x, value %02x\n",
2211                        name, value, STp->cln_sense_mask, STp->cln_sense_value);
2212         } else if (code == MT_ST_DEF_OPTIONS) {
2213                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2214                 value = (options & MT_ST_CLEAR_DEFAULT);
2215                 if (code == MT_ST_DEF_DENSITY) {
2216                         if (value == MT_ST_CLEAR_DEFAULT) {
2217                                 STm->default_density = (-1);
2218                                 DEBC( printk(KERN_INFO "%s: Density default disabled.\n",
2219                                        name));
2220                         } else {
2221                                 STm->default_density = value & 0xff;
2222                                 DEBC( printk(KERN_INFO "%s: Density default set to %x\n",
2223                                        name, STm->default_density));
2224                                 if (STp->ready == ST_READY) {
2225                                         STp->density_changed = 0;
2226                                         set_mode_densblk(STp, STm);
2227                                 }
2228                         }
2229                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2230                         if (value == MT_ST_CLEAR_DEFAULT) {
2231                                 STp->default_drvbuffer = 0xff;
2232                                 DEBC( printk(KERN_INFO
2233                                        "%s: Drive buffer default disabled.\n", name));
2234                         } else {
2235                                 STp->default_drvbuffer = value & 7;
2236                                 DEBC( printk(KERN_INFO
2237                                        "%s: Drive buffer default set to %x\n",
2238                                        name, STp->default_drvbuffer));
2239                                 if (STp->ready == ST_READY)
2240                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2241                         }
2242                 } else if (code == MT_ST_DEF_COMPRESSION) {
2243                         if (value == MT_ST_CLEAR_DEFAULT) {
2244                                 STm->default_compression = ST_DONT_TOUCH;
2245                                 DEBC( printk(KERN_INFO
2246                                        "%s: Compression default disabled.\n", name));
2247                         } else {
2248                                 if ((value & 0xff00) != 0) {
2249                                         STp->c_algo = (value & 0xff00) >> 8;
2250                                         DEBC( printk(KERN_INFO "%s: Compression algorithm set to 0x%x.\n",
2251                                                name, STp->c_algo));
2252                                 }
2253                                 if ((value & 0xff) != 0xff) {
2254                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2255                                         DEBC( printk(KERN_INFO "%s: Compression default set to %x\n",
2256                                                name, (value & 1)));
2257                                         if (STp->ready == ST_READY) {
2258                                                 STp->compression_changed = 0;
2259                                                 st_compression(STp, (STm->default_compression == ST_YES));
2260                                         }
2261                                 }
2262                         }
2263                 }
2264         } else
2265                 return (-EIO);
2266
2267         return 0;
2268 }
2269 \f
2270 #define MODE_HEADER_LENGTH  4
2271
2272 /* Mode header and page byte offsets */
2273 #define MH_OFF_DATA_LENGTH     0
2274 #define MH_OFF_MEDIUM_TYPE     1
2275 #define MH_OFF_DEV_SPECIFIC    2
2276 #define MH_OFF_BDESCS_LENGTH   3
2277 #define MP_OFF_PAGE_NBR        0
2278 #define MP_OFF_PAGE_LENGTH     1
2279
2280 /* Mode header and page bit masks */
2281 #define MH_BIT_WP              0x80
2282 #define MP_MSK_PAGE_NBR        0x3f
2283
2284 /* Don't return block descriptors */
2285 #define MODE_SENSE_OMIT_BDESCS 0x08
2286
2287 #define MODE_SELECT_PAGE_FORMAT 0x10
2288
2289 /* Read a mode page into the tape buffer. The block descriptors are included
2290    if incl_block_descs is true. The page control is ored to the page number
2291    parameter, if necessary. */
2292 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2293 {
2294         unsigned char cmd[MAX_COMMAND_SIZE];
2295         struct st_request *SRpnt = NULL;
2296
2297         memset(cmd, 0, MAX_COMMAND_SIZE);
2298         cmd[0] = MODE_SENSE;
2299         if (omit_block_descs)
2300                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2301         cmd[2] = page;
2302         cmd[4] = 255;
2303
2304         SRpnt = st_do_scsi(SRpnt, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2305                            STp->device->timeout, 0, 1);
2306         if (SRpnt == NULL)
2307                 return (STp->buffer)->syscall_result;
2308
2309         st_release_request(SRpnt);
2310
2311         return (STp->buffer)->syscall_result;
2312 }
2313
2314
2315 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2316    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2317 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2318 {
2319         int pgo;
2320         unsigned char cmd[MAX_COMMAND_SIZE];
2321         struct st_request *SRpnt = NULL;
2322
2323         memset(cmd, 0, MAX_COMMAND_SIZE);
2324         cmd[0] = MODE_SELECT;
2325         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2326         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2327         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2328
2329         /* Clear reserved fields */
2330         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2331         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2332         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2333         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2334
2335         SRpnt = st_do_scsi(SRpnt, STp, cmd, cmd[4], DMA_TO_DEVICE,
2336                            (slow ? STp->long_timeout : STp->device->timeout), 0, 1);
2337         if (SRpnt == NULL)
2338                 return (STp->buffer)->syscall_result;
2339
2340         st_release_request(SRpnt);
2341
2342         return (STp->buffer)->syscall_result;
2343 }
2344
2345
2346 #define COMPRESSION_PAGE        0x0f
2347 #define COMPRESSION_PAGE_LENGTH 16
2348
2349 #define CP_OFF_DCE_DCC          2
2350 #define CP_OFF_C_ALGO           7
2351
2352 #define DCE_MASK  0x80
2353 #define DCC_MASK  0x40
2354 #define RED_MASK  0x60
2355
2356
2357 /* Control the compression with mode page 15. Algorithm not changed if zero.
2358
2359    The block descriptors are read and written because Sony SDT-7000 does not
2360    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2361    Including block descriptors should not cause any harm to other drives. */
2362
2363 static int st_compression(struct scsi_tape * STp, int state)
2364 {
2365         int retval;
2366         int mpoffs;  /* Offset to mode page start */
2367         unsigned char *b_data = (STp->buffer)->b_data;
2368         DEB( char *name = tape_name(STp); )
2369
2370         if (STp->ready != ST_READY)
2371                 return (-EIO);
2372
2373         /* Read the current page contents */
2374         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2375         if (retval) {
2376                 DEBC(printk(ST_DEB_MSG "%s: Compression mode page not supported.\n",
2377                             name));
2378                 return (-EIO);
2379         }
2380
2381         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2382         DEBC(printk(ST_DEB_MSG "%s: Compression state is %d.\n", name,
2383                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0)));
2384
2385         /* Check if compression can be changed */
2386         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2387                 DEBC(printk(ST_DEB_MSG "%s: Compression not supported.\n", name));
2388                 return (-EIO);
2389         }
2390
2391         /* Do the change */
2392         if (state) {
2393                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2394                 if (STp->c_algo != 0)
2395                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2396         }
2397         else {
2398                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2399                 if (STp->c_algo != 0)
2400                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2401         }
2402
2403         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2404         if (retval) {
2405                 DEBC(printk(ST_DEB_MSG "%s: Compression change failed.\n", name));
2406                 return (-EIO);
2407         }
2408         DEBC(printk(ST_DEB_MSG "%s: Compression state changed to %d.\n",
2409                        name, state));
2410
2411         STp->compression_changed = 1;
2412         return 0;
2413 }
2414
2415
2416 /* Process the load and unload commands (does unload if the load code is zero) */
2417 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2418 {
2419         int retval = (-EIO), timeout;
2420         DEB( char *name = tape_name(STp); )
2421         unsigned char cmd[MAX_COMMAND_SIZE];
2422         struct st_partstat *STps;
2423         struct st_request *SRpnt;
2424
2425         if (STp->ready != ST_READY && !load_code) {
2426                 if (STp->ready == ST_NO_TAPE)
2427                         return (-ENOMEDIUM);
2428                 else
2429                         return (-EIO);
2430         }
2431
2432         memset(cmd, 0, MAX_COMMAND_SIZE);
2433         cmd[0] = START_STOP;
2434         if (load_code)
2435                 cmd[4] |= 1;
2436         /*
2437          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2438          */
2439         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2440             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2441                 DEBC(printk(ST_DEB_MSG "%s: Enhanced %sload slot %2d.\n",
2442                             name, (cmd[4]) ? "" : "un",
2443                             load_code - MT_ST_HPLOADER_OFFSET));
2444                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2445         }
2446         if (STp->immediate) {
2447                 cmd[1] = 1;     /* Don't wait for completion */
2448                 timeout = STp->device->timeout;
2449         }
2450         else
2451                 timeout = STp->long_timeout;
2452
2453         DEBC(
2454                 if (!load_code)
2455                 printk(ST_DEB_MSG "%s: Unloading tape.\n", name);
2456                 else
2457                 printk(ST_DEB_MSG "%s: Loading tape.\n", name);
2458                 );
2459
2460         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2461                            timeout, MAX_RETRIES, 1);
2462         if (!SRpnt)
2463                 return (STp->buffer)->syscall_result;
2464
2465         retval = (STp->buffer)->syscall_result;
2466         st_release_request(SRpnt);
2467
2468         if (!retval) {  /* SCSI command successful */
2469
2470                 if (!load_code) {
2471                         STp->rew_at_close = 0;
2472                         STp->ready = ST_NO_TAPE;
2473                 }
2474                 else {
2475                         STp->rew_at_close = STp->autorew_dev;
2476                         retval = check_tape(STp, filp);
2477                         if (retval > 0)
2478                                 retval = 0;
2479                 }
2480         }
2481         else {
2482                 STps = &(STp->ps[STp->partition]);
2483                 STps->drv_file = STps->drv_block = (-1);
2484         }
2485
2486         return retval;
2487 }
2488 \f
2489 #if DEBUG
2490 #define ST_DEB_FORWARD  0
2491 #define ST_DEB_BACKWARD 1
2492 static void deb_space_print(char *name, int direction, char *units, unsigned char *cmd)
2493 {
2494         s32 sc;
2495
2496         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2497         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2498         if (direction)
2499                 sc = -sc;
2500         printk(ST_DEB_MSG "%s: Spacing tape %s over %d %s.\n", name,
2501                direction ? "backward" : "forward", sc, units);
2502 }
2503 #endif
2504
2505
2506 /* Internal ioctl function */
2507 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2508 {
2509         int timeout;
2510         long ltmp;
2511         int ioctl_result;
2512         int chg_eof = 1;
2513         unsigned char cmd[MAX_COMMAND_SIZE];
2514         struct st_request *SRpnt;
2515         struct st_partstat *STps;
2516         int fileno, blkno, at_sm, undone;
2517         int datalen = 0, direction = DMA_NONE;
2518         char *name = tape_name(STp);
2519
2520         WARN_ON(STp->buffer->do_dio != 0);
2521         if (STp->ready != ST_READY) {
2522                 if (STp->ready == ST_NO_TAPE)
2523                         return (-ENOMEDIUM);
2524                 else
2525                         return (-EIO);
2526         }
2527         timeout = STp->long_timeout;
2528         STps = &(STp->ps[STp->partition]);
2529         fileno = STps->drv_file;
2530         blkno = STps->drv_block;
2531         at_sm = STps->at_sm;
2532
2533         memset(cmd, 0, MAX_COMMAND_SIZE);
2534         switch (cmd_in) {
2535         case MTFSFM:
2536                 chg_eof = 0;    /* Changed from the FSF after this */
2537         case MTFSF:
2538                 cmd[0] = SPACE;
2539                 cmd[1] = 0x01;  /* Space FileMarks */
2540                 cmd[2] = (arg >> 16);
2541                 cmd[3] = (arg >> 8);
2542                 cmd[4] = arg;
2543                 DEBC(deb_space_print(name, ST_DEB_FORWARD, "filemarks", cmd);)
2544                 if (fileno >= 0)
2545                         fileno += arg;
2546                 blkno = 0;
2547                 at_sm &= (arg == 0);
2548                 break;
2549         case MTBSFM:
2550                 chg_eof = 0;    /* Changed from the FSF after this */
2551         case MTBSF:
2552                 cmd[0] = SPACE;
2553                 cmd[1] = 0x01;  /* Space FileMarks */
2554                 ltmp = (-arg);
2555                 cmd[2] = (ltmp >> 16);
2556                 cmd[3] = (ltmp >> 8);
2557                 cmd[4] = ltmp;
2558                 DEBC(deb_space_print(name, ST_DEB_BACKWARD, "filemarks", cmd);)
2559                 if (fileno >= 0)
2560                         fileno -= arg;
2561                 blkno = (-1);   /* We can't know the block number */
2562                 at_sm &= (arg == 0);
2563                 break;
2564         case MTFSR:
2565                 cmd[0] = SPACE;
2566                 cmd[1] = 0x00;  /* Space Blocks */
2567                 cmd[2] = (arg >> 16);
2568                 cmd[3] = (arg >> 8);
2569                 cmd[4] = arg;
2570                 DEBC(deb_space_print(name, ST_DEB_FORWARD, "blocks", cmd);)
2571                 if (blkno >= 0)
2572                         blkno += arg;
2573                 at_sm &= (arg == 0);
2574                 break;
2575         case MTBSR:
2576                 cmd[0] = SPACE;
2577                 cmd[1] = 0x00;  /* Space Blocks */
2578                 ltmp = (-arg);
2579                 cmd[2] = (ltmp >> 16);
2580                 cmd[3] = (ltmp >> 8);
2581                 cmd[4] = ltmp;
2582                 DEBC(deb_space_print(name, ST_DEB_BACKWARD, "blocks", cmd);)
2583                 if (blkno >= 0)
2584                         blkno -= arg;
2585                 at_sm &= (arg == 0);
2586                 break;
2587         case MTFSS:
2588                 cmd[0] = SPACE;
2589                 cmd[1] = 0x04;  /* Space Setmarks */
2590                 cmd[2] = (arg >> 16);
2591                 cmd[3] = (arg >> 8);
2592                 cmd[4] = arg;
2593                 DEBC(deb_space_print(name, ST_DEB_FORWARD, "setmarks", cmd);)
2594                 if (arg != 0) {
2595                         blkno = fileno = (-1);
2596                         at_sm = 1;
2597                 }
2598                 break;
2599         case MTBSS:
2600                 cmd[0] = SPACE;
2601                 cmd[1] = 0x04;  /* Space Setmarks */
2602                 ltmp = (-arg);
2603                 cmd[2] = (ltmp >> 16);
2604                 cmd[3] = (ltmp >> 8);
2605                 cmd[4] = ltmp;
2606                 DEBC(deb_space_print(name, ST_DEB_BACKWARD, "setmarks", cmd);)
2607                 if (arg != 0) {
2608                         blkno = fileno = (-1);
2609                         at_sm = 1;
2610                 }
2611                 break;
2612         case MTWEOF:
2613         case MTWSM:
2614                 if (STp->write_prot)
2615                         return (-EACCES);
2616                 cmd[0] = WRITE_FILEMARKS;
2617                 if (cmd_in == MTWSM)
2618                         cmd[1] = 2;
2619                 cmd[2] = (arg >> 16);
2620                 cmd[3] = (arg >> 8);
2621                 cmd[4] = arg;
2622                 timeout = STp->device->timeout;
2623                 DEBC(
2624                      if (cmd_in == MTWEOF)
2625                                printk(ST_DEB_MSG "%s: Writing %d filemarks.\n", name,
2626                                  cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);
2627                      else
2628                                 printk(ST_DEB_MSG "%s: Writing %d setmarks.\n", name,
2629                                  cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);
2630                 )
2631                 if (fileno >= 0)
2632                         fileno += arg;
2633                 blkno = 0;
2634                 at_sm = (cmd_in == MTWSM);
2635                 break;
2636         case MTREW:
2637                 cmd[0] = REZERO_UNIT;
2638                 if (STp->immediate) {
2639                         cmd[1] = 1;     /* Don't wait for completion */
2640                         timeout = STp->device->timeout;
2641                 }
2642                 DEBC(printk(ST_DEB_MSG "%s: Rewinding tape.\n", name));
2643                 fileno = blkno = at_sm = 0;
2644                 break;
2645         case MTNOP:
2646                 DEBC(printk(ST_DEB_MSG "%s: No op on tape.\n", name));
2647                 return 0;       /* Should do something ? */
2648                 break;
2649         case MTRETEN:
2650                 cmd[0] = START_STOP;
2651                 if (STp->immediate) {
2652                         cmd[1] = 1;     /* Don't wait for completion */
2653                         timeout = STp->device->timeout;
2654                 }
2655                 cmd[4] = 3;
2656                 DEBC(printk(ST_DEB_MSG "%s: Retensioning tape.\n", name));
2657                 fileno = blkno = at_sm = 0;
2658                 break;
2659         case MTEOM:
2660                 if (!STp->fast_mteom) {
2661                         /* space to the end of tape */
2662                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2663                         fileno = STps->drv_file;
2664                         if (STps->eof >= ST_EOD_1)
2665                                 return 0;
2666                         /* The next lines would hide the number of spaced FileMarks
2667                            That's why I inserted the previous lines. I had no luck
2668                            with detecting EOM with FSF, so we go now to EOM.
2669                            Joerg Weule */
2670                 } else
2671                         fileno = (-1);
2672                 cmd[0] = SPACE;
2673                 cmd[1] = 3;
2674                 DEBC(printk(ST_DEB_MSG "%s: Spacing to end of recorded medium.\n",
2675                             name));
2676                 blkno = -1;
2677                 at_sm = 0;
2678                 break;
2679         case MTERASE:
2680                 if (STp->write_prot)
2681                         return (-EACCES);
2682                 cmd[0] = ERASE;
2683                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2684                 if (STp->immediate) {
2685                         cmd[1] |= 2;    /* Don't wait for completion */
2686                         timeout = STp->device->timeout;
2687                 }
2688                 else
2689                         timeout = STp->long_timeout * 8;
2690
2691                 DEBC(printk(ST_DEB_MSG "%s: Erasing tape.\n", name));
2692                 fileno = blkno = at_sm = 0;
2693                 break;
2694         case MTSETBLK:          /* Set block length */
2695         case MTSETDENSITY:      /* Set tape density */
2696         case MTSETDRVBUFFER:    /* Set drive buffering */
2697         case SET_DENS_AND_BLK:  /* Set density and block size */
2698                 chg_eof = 0;
2699                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2700                         return (-EIO);  /* Not allowed if data in buffer */
2701                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2702                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2703                     STp->max_block > 0 &&
2704                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2705                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2706                         printk(KERN_WARNING "%s: Illegal block size.\n", name);
2707                         return (-EINVAL);
2708                 }
2709                 cmd[0] = MODE_SELECT;
2710                 if ((STp->use_pf & USE_PF))
2711                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2712                 cmd[4] = datalen = 12;
2713                 direction = DMA_TO_DEVICE;
2714
2715                 memset((STp->buffer)->b_data, 0, 12);
2716                 if (cmd_in == MTSETDRVBUFFER)
2717                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2718                 else
2719                         (STp->buffer)->b_data[2] =
2720                             STp->drv_buffer << 4;
2721                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2722                 if (cmd_in == MTSETDENSITY) {
2723                         (STp->buffer)->b_data[4] = arg;
2724                         STp->density_changed = 1;       /* At least we tried ;-) */
2725                 } else if (cmd_in == SET_DENS_AND_BLK)
2726                         (STp->buffer)->b_data[4] = arg >> 24;
2727                 else
2728                         (STp->buffer)->b_data[4] = STp->density;
2729                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2730                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2731                         if (cmd_in == MTSETBLK)
2732                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2733                 } else
2734                         ltmp = STp->block_size;
2735                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2736                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2737                 (STp->buffer)->b_data[11] = ltmp;
2738                 timeout = STp->device->timeout;
2739                 DEBC(
2740                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2741                                 printk(ST_DEB_MSG
2742                                        "%s: Setting block size to %d bytes.\n", name,
2743                                        (STp->buffer)->b_data[9] * 65536 +
2744                                        (STp->buffer)->b_data[10] * 256 +
2745                                        (STp->buffer)->b_data[11]);
2746                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2747                                 printk(ST_DEB_MSG
2748                                        "%s: Setting density code to %x.\n", name,
2749                                        (STp->buffer)->b_data[4]);
2750                         if (cmd_in == MTSETDRVBUFFER)
2751                                 printk(ST_DEB_MSG
2752                                        "%s: Setting drive buffer code to %d.\n", name,
2753                                     ((STp->buffer)->b_data[2] >> 4) & 7);
2754                 )
2755                 break;
2756         default:
2757                 return (-ENOSYS);
2758         }
2759
2760         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2761                            timeout, MAX_RETRIES, 1);
2762         if (!SRpnt)
2763                 return (STp->buffer)->syscall_result;
2764
2765         ioctl_result = (STp->buffer)->syscall_result;
2766
2767         if (!ioctl_result) {    /* SCSI command successful */
2768                 st_release_request(SRpnt);
2769                 SRpnt = NULL;
2770                 STps->drv_block = blkno;
2771                 STps->drv_file = fileno;
2772                 STps->at_sm = at_sm;
2773
2774                 if (cmd_in == MTBSFM)
2775                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2776                 else if (cmd_in == MTFSFM)
2777                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2778
2779                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2780                         int old_block_size = STp->block_size;
2781                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2782                         if (STp->block_size != 0) {
2783                                 if (old_block_size == 0)
2784                                         normalize_buffer(STp->buffer);
2785                                 (STp->buffer)->buffer_blocks =
2786                                     (STp->buffer)->buffer_size / STp->block_size;
2787                         }
2788                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2789                         if (cmd_in == SET_DENS_AND_BLK)
2790                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2791                 } else if (cmd_in == MTSETDRVBUFFER)
2792                         STp->drv_buffer = (arg & 7);
2793                 else if (cmd_in == MTSETDENSITY)
2794                         STp->density = arg;
2795
2796                 if (cmd_in == MTEOM)
2797                         STps->eof = ST_EOD;
2798                 else if (cmd_in == MTFSF)
2799                         STps->eof = ST_FM;
2800                 else if (chg_eof)
2801                         STps->eof = ST_NOEOF;
2802
2803                 if (cmd_in == MTWEOF)
2804                         STps->rw = ST_IDLE;
2805         } else { /* SCSI command was not completely successful. Don't return
2806                     from this block without releasing the SCSI command block! */
2807                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
2808
2809                 if (cmdstatp->flags & SENSE_EOM) {
2810                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
2811                             cmd_in != MTBSR && cmd_in != MTBSS)
2812                                 STps->eof = ST_EOM_OK;
2813                         STps->drv_block = 0;
2814                 }
2815
2816                 if (cmdstatp->remainder_valid)
2817                         undone = (int)cmdstatp->uremainder64;
2818                 else
2819                         undone = 0;
2820
2821                 if (cmd_in == MTWEOF &&
2822                     cmdstatp->have_sense &&
2823                     (cmdstatp->flags & SENSE_EOM)) {
2824                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
2825                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
2826                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
2827                                 STps->eof = ST_NOEOF;
2828                         } else {  /* Writing EOF(s) failed */
2829                                 if (fileno >= 0)
2830                                         fileno -= undone;
2831                                 if (undone < arg)
2832                                         STps->eof = ST_NOEOF;
2833                         }
2834                         STps->drv_file = fileno;
2835                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
2836                         if (fileno >= 0)
2837                                 STps->drv_file = fileno - undone;
2838                         else
2839                                 STps->drv_file = fileno;
2840                         STps->drv_block = -1;
2841                         STps->eof = ST_NOEOF;
2842                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
2843                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
2844                                 undone = (-undone);
2845                         if (STps->drv_file >= 0)
2846                                 STps->drv_file = fileno + undone;
2847                         STps->drv_block = 0;
2848                         STps->eof = ST_NOEOF;
2849                 } else if (cmd_in == MTFSR) {
2850                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
2851                                 if (STps->drv_file >= 0)
2852                                         STps->drv_file++;
2853                                 STps->drv_block = 0;
2854                                 STps->eof = ST_FM;
2855                         } else {
2856                                 if (blkno >= undone)
2857                                         STps->drv_block = blkno - undone;
2858                                 else
2859                                         STps->drv_block = (-1);
2860                                 STps->eof = ST_NOEOF;
2861                         }
2862                 } else if (cmd_in == MTBSR) {
2863                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
2864                                 STps->drv_file--;
2865                                 STps->drv_block = (-1);
2866                         } else {
2867                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
2868                                         undone = (-undone);
2869                                 if (STps->drv_block >= 0)
2870                                         STps->drv_block = blkno + undone;
2871                         }
2872                         STps->eof = ST_NOEOF;
2873                 } else if (cmd_in == MTEOM) {
2874                         STps->drv_file = (-1);
2875                         STps->drv_block = (-1);
2876                         STps->eof = ST_EOD;
2877                 } else if (cmd_in == MTSETBLK ||
2878                            cmd_in == MTSETDENSITY ||
2879                            cmd_in == MTSETDRVBUFFER ||
2880                            cmd_in == SET_DENS_AND_BLK) {
2881                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
2882                             !(STp->use_pf & PF_TESTED)) {
2883                                 /* Try the other possible state of Page Format if not
2884                                    already tried */
2885                                 STp->use_pf = !STp->use_pf | PF_TESTED;
2886                                 st_release_request(SRpnt);
2887                                 SRpnt = NULL;
2888                                 return st_int_ioctl(STp, cmd_in, arg);
2889                         }
2890                 } else if (chg_eof)
2891                         STps->eof = ST_NOEOF;
2892
2893                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
2894                         STps->eof = ST_EOD;
2895
2896                 st_release_request(SRpnt);
2897                 SRpnt = NULL;
2898         }
2899
2900         return ioctl_result;
2901 }
2902 \f
2903
2904 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
2905    structure. */
2906
2907 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
2908                         int logical)
2909 {
2910         int result;
2911         unsigned char scmd[MAX_COMMAND_SIZE];
2912         struct st_request *SRpnt;
2913         DEB( char *name = tape_name(STp); )
2914
2915         if (STp->ready != ST_READY)
2916                 return (-EIO);
2917
2918         memset(scmd, 0, MAX_COMMAND_SIZE);
2919         if ((STp->device)->scsi_level < SCSI_2) {
2920                 scmd[0] = QFA_REQUEST_BLOCK;
2921                 scmd[4] = 3;
2922         } else {
2923                 scmd[0] = READ_POSITION;
2924                 if (!logical && !STp->scsi2_logical)
2925                         scmd[1] = 1;
2926         }
2927         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
2928                         STp->device->timeout, MAX_READY_RETRIES, 1);
2929         if (!SRpnt)
2930                 return (STp->buffer)->syscall_result;
2931
2932         if ((STp->buffer)->syscall_result != 0 ||
2933             (STp->device->scsi_level >= SCSI_2 &&
2934              ((STp->buffer)->b_data[0] & 4) != 0)) {
2935                 *block = *partition = 0;
2936                 DEBC(printk(ST_DEB_MSG "%s: Can't read tape position.\n", name));
2937                 result = (-EIO);
2938         } else {
2939                 result = 0;
2940                 if ((STp->device)->scsi_level < SCSI_2) {
2941                         *block = ((STp->buffer)->b_data[0] << 16)
2942                             + ((STp->buffer)->b_data[1] << 8)
2943                             + (STp->buffer)->b_data[2];
2944                         *partition = 0;
2945                 } else {
2946                         *block = ((STp->buffer)->b_data[4] << 24)
2947                             + ((STp->buffer)->b_data[5] << 16)
2948                             + ((STp->buffer)->b_data[6] << 8)
2949                             + (STp->buffer)->b_data[7];
2950                         *partition = (STp->buffer)->b_data[1];
2951                         if (((STp->buffer)->b_data[0] & 0x80) &&
2952                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
2953                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
2954                 }
2955                 DEBC(printk(ST_DEB_MSG "%s: Got tape pos. blk %d part %d.\n", name,
2956                             *block, *partition));
2957         }
2958         st_release_request(SRpnt);
2959         SRpnt = NULL;
2960
2961         return result;
2962 }
2963
2964
2965 /* Set the tape block and partition. Negative partition means that only the
2966    block should be set in vendor specific way. */
2967 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
2968                         int logical)
2969 {
2970         struct st_partstat *STps;
2971         int result, p;
2972         unsigned int blk;
2973         int timeout;
2974         unsigned char scmd[MAX_COMMAND_SIZE];
2975         struct st_request *SRpnt;
2976         DEB( char *name = tape_name(STp); )
2977
2978         if (STp->ready != ST_READY)
2979                 return (-EIO);
2980         timeout = STp->long_timeout;
2981         STps = &(STp->ps[STp->partition]);
2982
2983         DEBC(printk(ST_DEB_MSG "%s: Setting block to %d and partition to %d.\n",
2984                     name, block, partition));
2985         DEB(if (partition < 0)
2986                 return (-EIO); )
2987
2988         /* Update the location at the partition we are leaving */
2989         if ((!STp->can_partitions && partition != 0) ||
2990             partition >= ST_NBR_PARTITIONS)
2991                 return (-EINVAL);
2992         if (partition != STp->partition) {
2993                 if (get_location(STp, &blk, &p, 1))
2994                         STps->last_block_valid = 0;
2995                 else {
2996                         STps->last_block_valid = 1;
2997                         STps->last_block_visited = blk;
2998                         DEBC(printk(ST_DEB_MSG
2999                                     "%s: Visited block %d for partition %d saved.\n",
3000                                     name, blk, STp->partition));
3001                 }
3002         }
3003
3004         memset(scmd, 0, MAX_COMMAND_SIZE);
3005         if ((STp->device)->scsi_level < SCSI_2) {
3006                 scmd[0] = QFA_SEEK_BLOCK;
3007                 scmd[2] = (block >> 16);
3008                 scmd[3] = (block >> 8);
3009                 scmd[4] = block;
3010                 scmd[5] = 0;
3011         } else {
3012                 scmd[0] = SEEK_10;
3013                 scmd[3] = (block >> 24);
3014                 scmd[4] = (block >> 16);
3015                 scmd[5] = (block >> 8);
3016                 scmd[6] = block;
3017                 if (!logical && !STp->scsi2_logical)
3018                         scmd[1] = 4;
3019                 if (STp->partition != partition) {
3020                         scmd[1] |= 2;
3021                         scmd[8] = partition;
3022                         DEBC(printk(ST_DEB_MSG
3023                                     "%s: Trying to change partition from %d to %d\n",
3024                                     name, STp->partition, partition));
3025                 }
3026         }
3027         if (STp->immediate) {
3028                 scmd[1] |= 1;           /* Don't wait for completion */
3029                 timeout = STp->device->timeout;
3030         }
3031
3032         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3033                            timeout, MAX_READY_RETRIES, 1);
3034         if (!SRpnt)
3035                 return (STp->buffer)->syscall_result;
3036
3037         STps->drv_block = STps->drv_file = (-1);
3038         STps->eof = ST_NOEOF;
3039         if ((STp->buffer)->syscall_result != 0) {
3040                 result = (-EIO);
3041                 if (STp->can_partitions &&
3042                     (STp->device)->scsi_level >= SCSI_2 &&
3043                     (p = find_partition(STp)) >= 0)
3044                         STp->partition = p;
3045         } else {
3046                 if (STp->can_partitions) {
3047                         STp->partition = partition;
3048                         STps = &(STp->ps[partition]);
3049                         if (!STps->last_block_valid ||
3050                             STps->last_block_visited != block) {
3051                                 STps->at_sm = 0;
3052                                 STps->rw = ST_IDLE;
3053                         }
3054                 } else
3055                         STps->at_sm = 0;
3056                 if (block == 0)
3057                         STps->drv_block = STps->drv_file = 0;
3058                 result = 0;
3059         }
3060
3061         st_release_request(SRpnt);
3062         SRpnt = NULL;
3063
3064         return result;
3065 }
3066
3067
3068 /* Find the current partition number for the drive status. Called from open and
3069    returns either partition number of negative error code. */
3070 static int find_partition(struct scsi_tape *STp)
3071 {
3072         int i, partition;
3073         unsigned int block;
3074
3075         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3076                 return i;
3077         if (partition >= ST_NBR_PARTITIONS)
3078                 return (-EIO);
3079         return partition;
3080 }
3081
3082
3083 /* Change the partition if necessary */
3084 static int switch_partition(struct scsi_tape *STp)
3085 {
3086         struct st_partstat *STps;
3087
3088         if (STp->partition == STp->new_partition)
3089                 return 0;
3090         STps = &(STp->ps[STp->new_partition]);
3091         if (!STps->last_block_valid)
3092                 STps->last_block_visited = 0;
3093         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3094 }
3095 \f
3096 /* Functions for reading and writing the medium partition mode page. */
3097
3098 #define PART_PAGE   0x11
3099 #define PART_PAGE_FIXED_LENGTH 8
3100
3101 #define PP_OFF_MAX_ADD_PARTS   2
3102 #define PP_OFF_NBR_ADD_PARTS   3
3103 #define PP_OFF_FLAGS           4
3104 #define PP_OFF_PART_UNITS      6
3105 #define PP_OFF_RESERVED        7
3106
3107 #define PP_BIT_IDP             0x20
3108 #define PP_MSK_PSUM_MB         0x10
3109
3110 /* Get the number of partitions on the tape. As a side effect reads the
3111    mode page into the tape buffer. */
3112 static int nbr_partitions(struct scsi_tape *STp)
3113 {
3114         int result;
3115         DEB( char *name = tape_name(STp); )
3116
3117         if (STp->ready != ST_READY)
3118                 return (-EIO);
3119
3120         result = read_mode_page(STp, PART_PAGE, 1);
3121
3122         if (result) {
3123                 DEBC(printk(ST_DEB_MSG "%s: Can't read medium partition page.\n",
3124                             name));
3125                 result = (-EIO);
3126         } else {
3127                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3128                                               PP_OFF_NBR_ADD_PARTS] + 1;
3129                 DEBC(printk(ST_DEB_MSG "%s: Number of partitions %d.\n", name, result));
3130         }
3131
3132         return result;
3133 }
3134
3135
3136 /* Partition the tape into two partitions if size > 0 or one partition if
3137    size == 0.
3138
3139    The block descriptors are read and written because Sony SDT-7000 does not
3140    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3141
3142    My HP C1533A drive returns only one partition size field. This is used to
3143    set the size of partition 1. There is no size field for the default partition.
3144    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3145    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3146    The following algorithm is used to accommodate both drives: if the number of
3147    partition size fields is greater than the maximum number of additional partitions
3148    in the mode page, the second field is used. Otherwise the first field is used.
3149
3150    For Seagate DDS drives the page length must be 8 when no partitions is defined
3151    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3152    is acceptable also to some other old drives and enforced if the first partition
3153    size field is used for the first additional partition size.
3154  */
3155 static int partition_tape(struct scsi_tape *STp, int size)
3156 {
3157         char *name = tape_name(STp);
3158         int result;
3159         int pgo, psd_cnt, psdo;
3160         unsigned char *bp;
3161
3162         result = read_mode_page(STp, PART_PAGE, 0);
3163         if (result) {
3164                 DEBC(printk(ST_DEB_MSG "%s: Can't read partition mode page.\n", name));
3165                 return result;
3166         }
3167         /* The mode page is in the buffer. Let's modify it and write it. */
3168         bp = (STp->buffer)->b_data;
3169         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3170         DEBC(printk(ST_DEB_MSG "%s: Partition page length is %d bytes.\n",
3171                     name, bp[pgo + MP_OFF_PAGE_LENGTH] + 2));
3172
3173         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3174         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3175         if (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS]) {
3176                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest of the tape */
3177                 psdo += 2;
3178         }
3179         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3180
3181         DEBC(printk("%s: psd_cnt %d, max.parts %d, nbr_parts %d\n", name,
3182                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3183                     bp[pgo + PP_OFF_NBR_ADD_PARTS]));
3184
3185         if (size <= 0) {
3186                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3187                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3188                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3189                 DEBC(printk(ST_DEB_MSG "%s: Formatting tape with one partition.\n",
3190                             name));
3191         } else {
3192                 bp[psdo] = (size >> 8) & 0xff;
3193                 bp[psdo + 1] = size & 0xff;
3194                 bp[pgo + 3] = 1;
3195                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3196                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3197                 DEBC(printk(ST_DEB_MSG
3198                             "%s: Formatting tape with two partitions (1 = %d MB).\n",
3199                             name, size));
3200         }
3201         bp[pgo + PP_OFF_PART_UNITS] = 0;
3202         bp[pgo + PP_OFF_RESERVED] = 0;
3203         bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | PP_MSK_PSUM_MB;
3204
3205         result = write_mode_page(STp, PART_PAGE, 1);
3206         if (result) {
3207                 printk(KERN_INFO "%s: Partitioning of tape failed.\n", name);
3208                 result = (-EIO);
3209         }
3210
3211         return result;
3212 }
3213 \f
3214
3215
3216 /* The ioctl command */
3217 static int st_ioctl(struct inode *inode, struct file *file,
3218                     unsigned int cmd_in, unsigned long arg)
3219 {
3220         int i, cmd_nr, cmd_type, bt;
3221         int retval = 0;
3222         unsigned int blk;
3223         struct scsi_tape *STp = file->private_data;
3224         struct st_modedef *STm;
3225         struct st_partstat *STps;
3226         char *name = tape_name(STp);
3227         void __user *p = (void __user *)arg;
3228
3229         if (down_interruptible(&STp->lock))
3230                 return -ERESTARTSYS;
3231
3232         DEB(
3233         if (debugging && !STp->in_use) {
3234                 printk(ST_DEB_MSG "%s: Incorrect device.\n", name);
3235                 retval = (-EIO);
3236                 goto out;
3237         } ) /* end DEB */
3238
3239         STm = &(STp->modes[STp->current_mode]);
3240         STps = &(STp->ps[STp->partition]);
3241
3242         /*
3243          * If we are in the middle of error recovery, don't let anyone
3244          * else try and use this device.  Also, if error recovery fails, it
3245          * may try and take the device offline, in which case all further
3246          * access to the device is prohibited.
3247          */
3248         retval = scsi_nonblockable_ioctl(STp->device, cmd_in, p, file);
3249         if (!scsi_block_when_processing_errors(STp->device) || retval != -ENODEV)
3250                 goto out;
3251         retval = 0;
3252
3253         cmd_type = _IOC_TYPE(cmd_in);
3254         cmd_nr = _IOC_NR(cmd_in);
3255
3256         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3257                 struct mtop mtc;
3258
3259                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3260                         retval = (-EINVAL);
3261                         goto out;
3262                 }
3263
3264                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3265                 if (i) {
3266                         retval = (-EFAULT);
3267                         goto out;
3268                 }
3269
3270                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3271                         printk(KERN_WARNING
3272                                "%s: MTSETDRVBUFFER only allowed for root.\n", name);
3273                         retval = (-EPERM);
3274                         goto out;
3275                 }
3276                 if (!STm->defined &&
3277                     (mtc.mt_op != MTSETDRVBUFFER &&
3278                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3279                         retval = (-ENXIO);
3280                         goto out;
3281                 }
3282
3283                 if (!STp->pos_unknown) {
3284
3285                         if (STps->eof == ST_FM_HIT) {
3286                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3287                                     mtc.mt_op == MTEOM) {
3288                                         mtc.mt_count -= 1;
3289                                         if (STps->drv_file >= 0)
3290                                                 STps->drv_file += 1;
3291                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3292                                         mtc.mt_count += 1;
3293                                         if (STps->drv_file >= 0)
3294                                                 STps->drv_file += 1;
3295                                 }
3296                         }
3297
3298                         if (mtc.mt_op == MTSEEK) {
3299                                 /* Old position must be restored if partition will be
3300                                    changed */
3301                                 i = !STp->can_partitions ||
3302                                     (STp->new_partition != STp->partition);
3303                         } else {
3304                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3305                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3306                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3307                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3308                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3309                                     mtc.mt_op == MTCOMPRESSION;
3310                         }
3311                         i = flush_buffer(STp, i);
3312                         if (i < 0) {
3313                                 retval = i;
3314                                 goto out;
3315                         }
3316                         if (STps->rw == ST_WRITING &&
3317                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3318                              mtc.mt_op == MTSEEK ||
3319                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3320                                 i = st_int_ioctl(STp, MTWEOF, 1);
3321                                 if (i < 0) {
3322                                         retval = i;
3323                                         goto out;
3324                                 }
3325                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3326                                         mtc.mt_count++;
3327                                 STps->rw = ST_IDLE;
3328                              }
3329
3330                 } else {
3331                         /*
3332                          * If there was a bus reset, block further access
3333                          * to this device.  If the user wants to rewind the tape,
3334                          * then reset the flag and allow access again.
3335                          */
3336                         if (mtc.mt_op != MTREW &&
3337                             mtc.mt_op != MTOFFL &&
3338                             mtc.mt_op != MTRETEN &&
3339                             mtc.mt_op != MTERASE &&
3340                             mtc.mt_op != MTSEEK &&
3341                             mtc.mt_op != MTEOM) {
3342                                 retval = (-EIO);
3343                                 goto out;
3344                         }
3345                         reset_state(STp);
3346                         /* remove this when the midlevel properly clears was_reset */
3347                         STp->device->was_reset = 0;
3348                 }
3349
3350                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3351                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3352                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3353                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3354
3355                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3356                         do_door_lock(STp, 0);   /* Ignore result! */
3357
3358                 if (mtc.mt_op == MTSETDRVBUFFER &&
3359                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3360                         retval = st_set_options(STp, mtc.mt_count);
3361                         goto out;
3362                 }
3363
3364                 if (mtc.mt_op == MTSETPART) {
3365                         if (!STp->can_partitions ||
3366                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3367                                 retval = (-EINVAL);
3368                                 goto out;
3369                         }
3370                         if (mtc.mt_count >= STp->nbr_partitions &&
3371                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3372                                 retval = (-EIO);
3373                                 goto out;
3374                         }
3375                         if (mtc.mt_count >= STp->nbr_partitions) {
3376                                 retval = (-EINVAL);
3377                                 goto out;
3378                         }
3379                         STp->new_partition = mtc.mt_count;
3380                         retval = 0;
3381                         goto out;
3382                 }
3383
3384                 if (mtc.mt_op == MTMKPART) {
3385                         if (!STp->can_partitions) {
3386                                 retval = (-EINVAL);
3387                                 goto out;
3388                         }
3389                         if ((i = st_int_ioctl(STp, MTREW, 0)) < 0 ||
3390                             (i = partition_tape(STp, mtc.mt_count)) < 0) {
3391                                 retval = i;
3392                                 goto out;
3393                         }
3394                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3395                                 STp->ps[i].rw = ST_IDLE;
3396                                 STp->ps[i].at_sm = 0;
3397                                 STp->ps[i].last_block_valid = 0;
3398                         }
3399                         STp->partition = STp->new_partition = 0;
3400                         STp->nbr_partitions = 1;        /* Bad guess ?-) */
3401                         STps->drv_block = STps->drv_file = 0;
3402                         retval = 0;
3403                         goto out;
3404                 }
3405
3406                 if (mtc.mt_op == MTSEEK) {
3407                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3408                         if (!STp->can_partitions)
3409                                 STp->ps[0].rw = ST_IDLE;
3410                         retval = i;
3411                         goto out;
3412                 }
3413
3414                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3415                         retval = do_load_unload(STp, file, 0);
3416                         goto out;
3417                 }
3418
3419                 if (mtc.mt_op == MTLOAD) {
3420                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3421                         goto out;
3422                 }
3423
3424                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3425                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3426                         goto out;
3427                 }
3428
3429                 if (STp->can_partitions && STp->ready == ST_READY &&
3430                     (i = switch_partition(STp)) < 0) {
3431                         retval = i;
3432                         goto out;
3433                 }
3434
3435                 if (mtc.mt_op == MTCOMPRESSION)
3436                         retval = st_compression(STp, (mtc.mt_count & 1));
3437                 else
3438                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3439                 goto out;
3440         }
3441         if (!STm->defined) {
3442                 retval = (-ENXIO);
3443                 goto out;
3444         }
3445
3446         if ((i = flush_buffer(STp, 0)) < 0) {
3447                 retval = i;
3448                 goto out;
3449         }
3450         if (STp->can_partitions &&
3451             (i = switch_partition(STp)) < 0) {
3452                 retval = i;
3453                 goto out;
3454         }
3455
3456         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3457                 struct mtget mt_status;
3458
3459                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3460                          retval = (-EINVAL);
3461                          goto out;
3462                 }
3463
3464                 mt_status.mt_type = STp->tape_type;
3465                 mt_status.mt_dsreg =
3466                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3467                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3468                 mt_status.mt_blkno = STps->drv_block;
3469                 mt_status.mt_fileno = STps->drv_file;
3470                 if (STp->block_size != 0) {
3471                         if (STps->rw == ST_WRITING)
3472                                 mt_status.mt_blkno +=
3473                                     (STp->buffer)->buffer_bytes / STp->block_size;
3474                         else if (STps->rw == ST_READING)
3475                                 mt_status.mt_blkno -=
3476                                         ((STp->buffer)->buffer_bytes +
3477                                          STp->block_size - 1) / STp->block_size;
3478                 }
3479
3480                 mt_status.mt_gstat = 0;
3481                 if (STp->drv_write_prot)
3482                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3483                 if (mt_status.mt_blkno == 0) {
3484                         if (mt_status.mt_fileno == 0)
3485                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3486                         else
3487                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3488                 }
3489                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3490                 mt_status.mt_resid = STp->partition;
3491                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3492                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3493                 else if (STps->eof >= ST_EOM_OK)
3494                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3495                 if (STp->density == 1)
3496                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3497                 else if (STp->density == 2)
3498                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3499                 else if (STp->density == 3)
3500                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3501                 if (STp->ready == ST_READY)
3502                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3503                 if (STp->ready == ST_NO_TAPE)
3504                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3505                 if (STps->at_sm)
3506                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3507                 if (STm->do_async_writes ||
3508                     (STm->do_buffer_writes && STp->block_size != 0) ||
3509                     STp->drv_buffer != 0)
3510                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3511                 if (STp->cleaning_req)
3512                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3513
3514                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3515                 if (i) {
3516                         retval = (-EFAULT);
3517                         goto out;
3518                 }
3519
3520                 STp->recover_reg = 0;           /* Clear after read */
3521                 retval = 0;
3522                 goto out;
3523         }                       /* End of MTIOCGET */
3524         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3525                 struct mtpos mt_pos;
3526                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3527                          retval = (-EINVAL);
3528                          goto out;
3529                 }
3530                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3531                         retval = i;
3532                         goto out;
3533                 }
3534                 mt_pos.mt_blkno = blk;
3535                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3536                 if (i)
3537                         retval = (-EFAULT);
3538                 goto out;
3539         }
3540         up(&STp->lock);
3541         switch (cmd_in) {
3542                 case SCSI_IOCTL_GET_IDLUN:
3543                 case SCSI_IOCTL_GET_BUS_NUMBER:
3544                         break;
3545                 default:
3546                         if ((cmd_in == SG_IO ||
3547                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3548                              cmd_in == CDROM_SEND_PACKET) &&
3549                             !capable(CAP_SYS_RAWIO))
3550                                 i = -EPERM;
3551                         else
3552                                 i = scsi_cmd_ioctl(file, STp->disk->queue,
3553                                                    STp->disk, cmd_in, p);
3554                         if (i != -ENOTTY)
3555                                 return i;
3556                         break;
3557         }
3558         retval = scsi_ioctl(STp->device, cmd_in, p);
3559         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3560                 STp->rew_at_close = 0;
3561                 STp->ready = ST_NO_TAPE;
3562         }
3563         return retval;
3564
3565  out:
3566         up(&STp->lock);
3567         return retval;
3568 }
3569
3570 #ifdef CONFIG_COMPAT
3571 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3572 {
3573         struct scsi_tape *STp = file->private_data;
3574         struct scsi_device *sdev = STp->device;
3575         int ret = -ENOIOCTLCMD;
3576         if (sdev->host->hostt->compat_ioctl) {
3577
3578                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3579
3580         }
3581         return ret;
3582 }
3583 #endif
3584
3585 \f
3586
3587 /* Try to allocate a new tape buffer. Calling function must not hold
3588    dev_arr_lock. */
3589 static struct st_buffer *
3590  new_tape_buffer(int from_initialization, int need_dma, int max_sg)
3591 {
3592         int i, got = 0;
3593         gfp_t priority;
3594         struct st_buffer *tb;
3595
3596         if (from_initialization)
3597                 priority = GFP_ATOMIC;
3598         else
3599                 priority = GFP_KERNEL;
3600
3601         i = sizeof(struct st_buffer) + (max_sg - 1) * sizeof(struct scatterlist) +
3602                 max_sg * sizeof(struct st_buf_fragment);
3603         tb = kzalloc(i, priority);
3604         if (!tb) {
3605                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3606                 return NULL;
3607         }
3608         tb->frp_segs = tb->orig_frp_segs = 0;
3609         tb->use_sg = max_sg;
3610         tb->frp = (struct st_buf_fragment *)(&(tb->sg[0]) + max_sg);
3611
3612         tb->dma = need_dma;
3613         tb->buffer_size = got;
3614
3615         return tb;
3616 }
3617
3618
3619 /* Try to allocate enough space in the tape buffer */
3620 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3621 {
3622         int segs, nbr, max_segs, b_size, order, got;
3623         gfp_t priority;
3624
3625         if (new_size <= STbuffer->buffer_size)
3626                 return 1;
3627
3628         if (STbuffer->buffer_size <= PAGE_SIZE)
3629                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3630
3631         max_segs = STbuffer->use_sg;
3632         nbr = max_segs - STbuffer->frp_segs;
3633         if (nbr <= 0)
3634                 return 0;
3635
3636         priority = GFP_KERNEL | __GFP_NOWARN;
3637         if (need_dma)
3638                 priority |= GFP_DMA;
3639         for (b_size = PAGE_SIZE, order=0; order <= 6 &&
3640              b_size < new_size - STbuffer->buffer_size;
3641              order++, b_size *= 2)
3642                 ;  /* empty */
3643
3644         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3645              segs < max_segs && got < new_size;) {
3646                 STbuffer->frp[segs].page = alloc_pages(priority, order);
3647                 if (STbuffer->frp[segs].page == NULL) {
3648                         if (new_size - got <= (max_segs - segs) * b_size / 2) {
3649                                 b_size /= 2; /* Large enough for the rest of the buffers */
3650                                 order--;
3651                                 continue;
3652                         }
3653                         DEB(STbuffer->buffer_size = got);
3654                         normalize_buffer(STbuffer);
3655                         return 0;
3656                 }
3657                 STbuffer->frp[segs].length = b_size;
3658                 STbuffer->frp_segs += 1;
3659                 got += b_size;
3660                 STbuffer->buffer_size = got;
3661                 segs++;
3662         }
3663         STbuffer->b_data = page_address(STbuffer->frp[0].page);
3664
3665         return 1;
3666 }
3667
3668
3669 /* Release the extra buffer */
3670 static void normalize_buffer(struct st_buffer * STbuffer)
3671 {
3672         int i, order;
3673
3674         for (i = STbuffer->orig_frp_segs; i < STbuffer->frp_segs; i++) {
3675                 order = get_order(STbuffer->frp[i].length);
3676                 __free_pages(STbuffer->frp[i].page, order);
3677                 STbuffer->buffer_size -= STbuffer->frp[i].length;
3678         }
3679         STbuffer->frp_segs = STbuffer->orig_frp_segs;
3680         STbuffer->frp_sg_current = 0;
3681         STbuffer->sg_segs = 0;
3682 }
3683
3684
3685 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3686    negative error code. */
3687 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3688 {
3689         int i, cnt, res, offset;
3690
3691         for (i = 0, offset = st_bp->buffer_bytes;
3692              i < st_bp->frp_segs && offset >= st_bp->frp[i].length; i++)
3693                 offset -= st_bp->frp[i].length;
3694         if (i == st_bp->frp_segs) {     /* Should never happen */
3695                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3696                 return (-EIO);
3697         }
3698         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3699                 cnt = st_bp->frp[i].length - offset < do_count ?
3700                     st_bp->frp[i].length - offset : do_count;
3701                 res = copy_from_user(page_address(st_bp->frp[i].page) + offset, ubp, cnt);
3702                 if (res)
3703                         return (-EFAULT);
3704                 do_count -= cnt;
3705                 st_bp->buffer_bytes += cnt;
3706                 ubp += cnt;
3707                 offset = 0;
3708         }
3709         if (do_count) /* Should never happen */
3710                 return (-EIO);
3711
3712         return 0;
3713 }
3714
3715
3716 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
3717    negative error code. */
3718 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
3719 {
3720         int i, cnt, res, offset;
3721
3722         for (i = 0, offset = st_bp->read_pointer;
3723              i < st_bp->frp_segs && offset >= st_bp->frp[i].length; i++)
3724                 offset -= st_bp->frp[i].length;
3725         if (i == st_bp->frp_segs) {     /* Should never happen */
3726                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
3727                 return (-EIO);
3728         }
3729         for (; i < st_bp->frp_segs && do_count > 0; i++) {
3730                 cnt = st_bp->frp[i].length - offset < do_count ?
3731                     st_bp->frp[i].length - offset : do_count;
3732                 res = copy_to_user(ubp, page_address(st_bp->frp[i].page) + offset, cnt);
3733                 if (res)
3734                         return (-EFAULT);
3735                 do_count -= cnt;
3736                 st_bp->buffer_bytes -= cnt;
3737                 st_bp->read_pointer += cnt;
3738                 ubp += cnt;
3739                 offset = 0;
3740         }
3741         if (do_count) /* Should never happen */
3742                 return (-EIO);
3743
3744         return 0;
3745 }
3746
3747
3748 /* Move data towards start of buffer */
3749 static void move_buffer_data(struct st_buffer * st_bp, int offset)
3750 {
3751         int src_seg, dst_seg, src_offset = 0, dst_offset;
3752         int count, total;
3753
3754         if (offset == 0)
3755                 return;
3756
3757         total=st_bp->buffer_bytes - offset;
3758         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
3759                 src_offset = offset;
3760                 if (src_offset < st_bp->frp[src_seg].length)
3761                         break;
3762                 offset -= st_bp->frp[src_seg].length;
3763         }
3764
3765         st_bp->buffer_bytes = st_bp->read_pointer = total;
3766         for (dst_seg=dst_offset=0; total > 0; ) {
3767                 count = min(st_bp->frp[dst_seg].length - dst_offset,
3768                             st_bp->frp[src_seg].length - src_offset);
3769                 memmove(page_address(st_bp->frp[dst_seg].page) + dst_offset,
3770                         page_address(st_bp->frp[src_seg].page) + src_offset, count);
3771                 src_offset += count;
3772                 if (src_offset >= st_bp->frp[src_seg].length) {
3773                         src_seg++;
3774                         src_offset = 0;
3775                 }
3776                 dst_offset += count;
3777                 if (dst_offset >= st_bp->frp[dst_seg].length) {
3778                         dst_seg++;
3779                         dst_offset = 0;
3780                 }
3781                 total -= count;
3782         }
3783 }
3784
3785
3786 /* Fill the s/g list up to the length required for this transfer */
3787 static void buf_to_sg(struct st_buffer *STbp, unsigned int length)
3788 {
3789         int i;
3790         unsigned int count;
3791         struct scatterlist *sg;
3792         struct st_buf_fragment *frp;
3793
3794         if (length == STbp->frp_sg_current)
3795                 return;   /* work already done */
3796
3797         sg = &(STbp->sg[0]);
3798         frp = STbp->frp;
3799         for (i=count=0; count < length; i++) {
3800                 sg[i].page = frp[i].page;
3801                 if (length - count > frp[i].length)
3802                         sg[i].length = frp[i].length;
3803                 else
3804                         sg[i].length = length - count;
3805                 count += sg[i].length;
3806                 sg[i].offset = 0;
3807         }
3808         STbp->sg_segs = i;
3809         STbp->frp_sg_current = length;
3810 }
3811
3812
3813 /* Validate the options from command line or module parameters */
3814 static void validate_options(void)
3815 {
3816         if (buffer_kbs > 0)
3817                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
3818         if (max_sg_segs >= ST_FIRST_SG)
3819                 st_max_sg_segs = max_sg_segs;
3820 }
3821
3822 #ifndef MODULE
3823 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
3824  */
3825 static int __init st_setup(char *str)
3826 {
3827         int i, len, ints[5];
3828         char *stp;
3829
3830         stp = get_options(str, ARRAY_SIZE(ints), ints);
3831
3832         if (ints[0] > 0) {
3833                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
3834                         if (parms[i].val)
3835                                 *parms[i].val = ints[i + 1];
3836         } else {
3837                 while (stp != NULL) {
3838                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
3839                                 len = strlen(parms[i].name);
3840                                 if (!strncmp(stp, parms[i].name, len) &&
3841                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
3842                                         if (parms[i].val)
3843                                                 *parms[i].val =
3844                                                         simple_strtoul(stp + len + 1, NULL, 0);
3845                                         else
3846                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
3847                                                        parms[i].name);
3848                                         break;
3849                                 }
3850                         }
3851                         if (i >= ARRAY_SIZE(parms))
3852                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
3853                                         stp);
3854                         stp = strchr(stp, ',');
3855                         if (stp)
3856                                 stp++;
3857                 }
3858         }
3859
3860         validate_options();
3861
3862         return 1;
3863 }
3864
3865 __setup("st=", st_setup);
3866
3867 #endif
3868
3869 static const struct file_operations st_fops =
3870 {
3871         .owner =        THIS_MODULE,
3872         .read =         st_read,
3873         .write =        st_write,
3874         .ioctl =        st_ioctl,
3875 #ifdef CONFIG_COMPAT
3876         .compat_ioctl = st_compat_ioctl,
3877 #endif
3878         .open =         st_open,
3879         .flush =        st_flush,
3880         .release =      st_release,
3881 };
3882
3883 static int st_probe(struct device *dev)
3884 {
3885         struct scsi_device *SDp = to_scsi_device(dev);
3886         struct gendisk *disk = NULL;
3887         struct cdev *cdev = NULL;
3888         struct scsi_tape *tpnt = NULL;
3889         struct st_modedef *STm;
3890         struct st_partstat *STps;
3891         struct st_buffer *buffer;
3892         int i, j, mode, dev_num, error;
3893         char *stp;
3894
3895         if (SDp->type != TYPE_TAPE)
3896                 return -ENODEV;
3897         if ((stp = st_incompatible(SDp))) {
3898                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
3899                 printk(KERN_INFO "st: The suggested driver is %s.\n", stp);
3900                 return -ENODEV;
3901         }
3902
3903         i = min(SDp->request_queue->max_hw_segments,
3904                 SDp->request_queue->max_phys_segments);
3905         if (st_max_sg_segs < i)
3906                 i = st_max_sg_segs;
3907         buffer = new_tape_buffer(1, (SDp->host)->unchecked_isa_dma, i);
3908         if (buffer == NULL) {
3909                 printk(KERN_ERR
3910                        "st: Can't allocate new tape buffer. Device not attached.\n");
3911                 goto out;
3912         }
3913
3914         disk = alloc_disk(1);
3915         if (!disk) {
3916                 printk(KERN_ERR "st: out of memory. Device not attached.\n");
3917                 goto out_buffer_free;
3918         }
3919
3920         write_lock(&st_dev_arr_lock);
3921         if (st_nr_dev >= st_dev_max) {
3922                 struct scsi_tape **tmp_da;
3923                 int tmp_dev_max;
3924
3925                 tmp_dev_max = max(st_nr_dev * 2, 8);
3926                 if (tmp_dev_max > ST_MAX_TAPES)
3927                         tmp_dev_max = ST_MAX_TAPES;
3928                 if (tmp_dev_max <= st_nr_dev) {
3929                         write_unlock(&st_dev_arr_lock);
3930                         printk(KERN_ERR "st: Too many tape devices (max. %d).\n",
3931                                ST_MAX_TAPES);
3932                         goto out_put_disk;
3933                 }
3934
3935                 tmp_da = kzalloc(tmp_dev_max * sizeof(struct scsi_tape *), GFP_ATOMIC);
3936                 if (tmp_da == NULL) {
3937                         write_unlock(&st_dev_arr_lock);
3938                         printk(KERN_ERR "st: Can't extend device array.\n");
3939                         goto out_put_disk;
3940                 }
3941
3942                 if (scsi_tapes != NULL) {
3943                         memcpy(tmp_da, scsi_tapes,
3944                                st_dev_max * sizeof(struct scsi_tape *));
3945                         kfree(scsi_tapes);
3946                 }
3947                 scsi_tapes = tmp_da;
3948
3949                 st_dev_max = tmp_dev_max;
3950         }
3951
3952         for (i = 0; i < st_dev_max; i++)
3953                 if (scsi_tapes[i] == NULL)
3954                         break;
3955         if (i >= st_dev_max)
3956                 panic("scsi_devices corrupt (st)");
3957
3958         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
3959         if (tpnt == NULL) {
3960                 write_unlock(&st_dev_arr_lock);
3961                 printk(KERN_ERR "st: Can't allocate device descriptor.\n");
3962                 goto out_put_disk;
3963         }
3964         kref_init(&tpnt->kref);
3965         tpnt->disk = disk;
3966         sprintf(disk->disk_name, "st%d", i);
3967         disk->private_data = &tpnt->driver;
3968         disk->queue = SDp->request_queue;
3969         tpnt->driver = &st_template;
3970         scsi_tapes[i] = tpnt;
3971         dev_num = i;
3972
3973         tpnt->device = SDp;
3974         if (SDp->scsi_level <= 2)
3975                 tpnt->tape_type = MT_ISSCSI1;
3976         else
3977                 tpnt->tape_type = MT_ISSCSI2;
3978
3979         tpnt->buffer = buffer;
3980         tpnt->buffer->last_SRpnt = NULL;
3981
3982         tpnt->inited = 0;
3983         tpnt->dirty = 0;
3984         tpnt->in_use = 0;
3985         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
3986         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
3987         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
3988         tpnt->density = 0;
3989         tpnt->do_auto_lock = ST_AUTO_LOCK;
3990         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
3991         tpnt->can_partitions = 0;
3992         tpnt->two_fm = ST_TWO_FM;
3993         tpnt->fast_mteom = ST_FAST_MTEOM;
3994         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
3995         tpnt->immediate = ST_NOWAIT;
3996         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
3997         tpnt->partition = 0;
3998         tpnt->new_partition = 0;
3999         tpnt->nbr_partitions = 0;
4000         tpnt->device->timeout = ST_TIMEOUT;
4001         tpnt->long_timeout = ST_LONG_TIMEOUT;
4002         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4003
4004         for (i = 0; i < ST_NBR_MODES; i++) {
4005                 STm = &(tpnt->modes[i]);
4006                 STm->defined = 0;
4007                 STm->sysv = ST_SYSV;
4008                 STm->defaults_for_writes = 0;
4009                 STm->do_async_writes = ST_ASYNC_WRITES;
4010                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4011                 STm->do_read_ahead = ST_READ_AHEAD;
4012                 STm->default_compression = ST_DONT_TOUCH;
4013                 STm->default_blksize = (-1);    /* No forced size */
4014                 STm->default_density = (-1);    /* No forced density */
4015         }
4016
4017         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4018                 STps = &(tpnt->ps[i]);
4019                 STps->rw = ST_IDLE;
4020                 STps->eof = ST_NOEOF;
4021                 STps->at_sm = 0;
4022                 STps->last_block_valid = 0;
4023                 STps->drv_block = (-1);
4024                 STps->drv_file = (-1);
4025         }
4026
4027         tpnt->current_mode = 0;
4028         tpnt->modes[0].defined = 1;
4029
4030         tpnt->density_changed = tpnt->compression_changed =
4031             tpnt->blksize_changed = 0;
4032         init_MUTEX(&tpnt->lock);
4033
4034         st_nr_dev++;
4035         write_unlock(&st_dev_arr_lock);
4036
4037         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4038                 STm = &(tpnt->modes[mode]);
4039                 for (j=0; j < 2; j++) {
4040                         cdev = cdev_alloc();
4041                         if (!cdev) {
4042                                 printk(KERN_ERR
4043                                        "st%d: out of memory. Device not attached.\n",
4044                                        dev_num);
4045                                 goto out_free_tape;
4046                         }
4047                         cdev->owner = THIS_MODULE;
4048                         cdev->ops = &st_fops;
4049
4050                         error = cdev_add(cdev,
4051                                          MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, j)),
4052                                          1);
4053                         if (error) {
4054                                 printk(KERN_ERR "st%d: Can't add %s-rewind mode %d\n",
4055                                        dev_num, j ? "non" : "auto", mode);
4056                                 printk(KERN_ERR "st%d: Device not attached.\n", dev_num);
4057                                 goto out_free_tape;
4058                         }
4059                         STm->cdevs[j] = cdev;
4060
4061                 }
4062                 error = do_create_class_files(tpnt, dev_num, mode);
4063                 if (error)
4064                         goto out_free_tape;
4065         }
4066
4067         sdev_printk(KERN_NOTICE, SDp,
4068                     "Attached scsi tape %s\n", tape_name(tpnt));
4069         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4070                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4071                     queue_dma_alignment(SDp->request_queue) + 1);
4072
4073         return 0;
4074
4075 out_free_tape:
4076         for (mode=0; mode < ST_NBR_MODES; mode++) {
4077                 STm = &(tpnt->modes[mode]);
4078                 sysfs_remove_link(&tpnt->device->sdev_gendev.kobj,
4079                                   "tape");
4080                 for (j=0; j < 2; j++) {
4081                         if (STm->cdevs[j]) {
4082                                 if (cdev == STm->cdevs[j])
4083                                         cdev = NULL;
4084                                 class_device_destroy(st_sysfs_class,
4085                                                      MKDEV(SCSI_TAPE_MAJOR,
4086                                                            TAPE_MINOR(i, mode, j)));
4087                                 cdev_del(STm->cdevs[j]);
4088                         }
4089                 }
4090         }
4091         if (cdev)
4092                 cdev_del(cdev);
4093         write_lock(&st_dev_arr_lock);
4094         scsi_tapes[dev_num] = NULL;
4095         st_nr_dev--;
4096         write_unlock(&st_dev_arr_lock);
4097 out_put_disk:
4098         put_disk(disk);
4099         kfree(tpnt);
4100 out_buffer_free:
4101         kfree(buffer);
4102 out:
4103         return -ENODEV;
4104 };
4105
4106
4107 static int st_remove(struct device *dev)
4108 {
4109         struct scsi_device *SDp = to_scsi_device(dev);
4110         struct scsi_tape *tpnt;
4111         int i, j, mode;
4112
4113         write_lock(&st_dev_arr_lock);
4114         for (i = 0; i < st_dev_max; i++) {
4115                 tpnt = scsi_tapes[i];
4116                 if (tpnt != NULL && tpnt->device == SDp) {
4117                         scsi_tapes[i] = NULL;
4118                         st_nr_dev--;
4119                         write_unlock(&st_dev_arr_lock);
4120                         sysfs_remove_link(&tpnt->device->sdev_gendev.kobj,
4121                                           "tape");
4122                         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4123                                 for (j=0; j < 2; j++) {
4124                                         class_device_destroy(st_sysfs_class,
4125                                                              MKDEV(SCSI_TAPE_MAJOR,
4126                                                                    TAPE_MINOR(i, mode, j)));
4127                                         cdev_del(tpnt->modes[mode].cdevs[j]);
4128                                         tpnt->modes[mode].cdevs[j] = NULL;
4129                                 }
4130                         }
4131
4132                         mutex_lock(&st_ref_mutex);
4133                         kref_put(&tpnt->kref, scsi_tape_release);
4134                         mutex_unlock(&st_ref_mutex);
4135                         return 0;
4136                 }
4137         }
4138
4139         write_unlock(&st_dev_arr_lock);
4140         return 0;
4141 }
4142
4143 /**
4144  *      scsi_tape_release - Called to free the Scsi_Tape structure
4145  *      @kref: pointer to embedded kref
4146  *
4147  *      st_ref_mutex must be held entering this routine.  Because it is
4148  *      called on last put, you should always use the scsi_tape_get()
4149  *      scsi_tape_put() helpers which manipulate the semaphore directly
4150  *      and never do a direct kref_put().
4151  **/
4152 static void scsi_tape_release(struct kref *kref)
4153 {
4154         struct scsi_tape *tpnt = to_scsi_tape(kref);
4155         struct gendisk *disk = tpnt->disk;
4156
4157         tpnt->device = NULL;
4158
4159         if (tpnt->buffer) {
4160                 tpnt->buffer->orig_frp_segs = 0;
4161                 normalize_buffer(tpnt->buffer);
4162                 kfree(tpnt->buffer);
4163         }
4164
4165         disk->private_data = NULL;
4166         put_disk(disk);
4167         kfree(tpnt);
4168         return;
4169 }
4170
4171 static int __init init_st(void)
4172 {
4173         int err;
4174
4175         validate_options();
4176
4177         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4178                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4179
4180         st_sysfs_class = class_create(THIS_MODULE, "scsi_tape");
4181         if (IS_ERR(st_sysfs_class)) {
4182                 printk(KERN_ERR "Unable create sysfs class for SCSI tapes\n");
4183                 return PTR_ERR(st_sysfs_class);
4184         }
4185
4186         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4187                                      ST_MAX_TAPE_ENTRIES, "st");
4188         if (err) {
4189                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4190                        SCSI_TAPE_MAJOR);
4191                 goto err_class;
4192         }
4193
4194         err = scsi_register_driver(&st_template.gendrv);
4195         if (err)
4196                 goto err_chrdev;
4197
4198         err = do_create_sysfs_files();
4199         if (err)
4200                 goto err_scsidrv;
4201
4202         return 0;
4203
4204 err_scsidrv:
4205         scsi_unregister_driver(&st_template.gendrv);
4206 err_chrdev:
4207         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4208                                  ST_MAX_TAPE_ENTRIES);
4209 err_class:
4210         class_destroy(st_sysfs_class);
4211         return err;
4212 }
4213
4214 static void __exit exit_st(void)
4215 {
4216         do_remove_sysfs_files();
4217         scsi_unregister_driver(&st_template.gendrv);
4218         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4219                                  ST_MAX_TAPE_ENTRIES);
4220         class_destroy(st_sysfs_class);
4221         kfree(scsi_tapes);
4222         printk(KERN_INFO "st: Unloaded.\n");
4223 }
4224
4225 module_init(init_st);
4226 module_exit(exit_st);
4227
4228
4229 /* The sysfs driver interface. Read-only at the moment */
4230 static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
4231 {
4232         return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4233 }
4234 static DRIVER_ATTR(try_direct_io, S_IRUGO, st_try_direct_io_show, NULL);
4235
4236 static ssize_t st_fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4237 {
4238         return snprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4239 }
4240 static DRIVER_ATTR(fixed_buffer_size, S_IRUGO, st_fixed_buffer_size_show, NULL);
4241
4242 static ssize_t st_max_sg_segs_show(struct device_driver *ddp, char *buf)
4243 {
4244         return snprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4245 }
4246 static DRIVER_ATTR(max_sg_segs, S_IRUGO, st_max_sg_segs_show, NULL);
4247
4248 static ssize_t st_version_show(struct device_driver *ddd, char *buf)
4249 {
4250         return snprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4251 }
4252 static DRIVER_ATTR(version, S_IRUGO, st_version_show, NULL);
4253
4254 static int do_create_sysfs_files(void)
4255 {
4256         struct device_driver *sysfs = &st_template.gendrv;
4257         int err;
4258
4259         err = driver_create_file(sysfs, &driver_attr_try_direct_io);
4260         if (err)
4261                 return err;
4262         err = driver_create_file(sysfs, &driver_attr_fixed_buffer_size);
4263         if (err)
4264                 goto err_try_direct_io;
4265         err = driver_create_file(sysfs, &driver_attr_max_sg_segs);
4266         if (err)
4267                 goto err_attr_fixed_buf;
4268         err = driver_create_file(sysfs, &driver_attr_version);
4269         if (err)
4270                 goto err_attr_max_sg;
4271
4272         return 0;
4273
4274 err_attr_max_sg:
4275         driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4276 err_attr_fixed_buf:
4277         driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4278 err_try_direct_io:
4279         driver_remove_file(sysfs, &driver_attr_try_direct_io);
4280         return err;
4281 }
4282
4283 static void do_remove_sysfs_files(void)
4284 {
4285         struct device_driver *sysfs = &st_template.gendrv;
4286
4287         driver_remove_file(sysfs, &driver_attr_version);
4288         driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4289         driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4290         driver_remove_file(sysfs, &driver_attr_try_direct_io);
4291 }
4292
4293
4294 /* The sysfs simple class interface */
4295 static ssize_t st_defined_show(struct class_device *class_dev, char *buf)
4296 {
4297         struct st_modedef *STm = (struct st_modedef *)class_get_devdata(class_dev);
4298         ssize_t l = 0;
4299
4300         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4301         return l;
4302 }
4303
4304 CLASS_DEVICE_ATTR(defined, S_IRUGO, st_defined_show, NULL);
4305
4306 static ssize_t st_defblk_show(struct class_device *class_dev, char *buf)
4307 {
4308         struct st_modedef *STm = (struct st_modedef *)class_get_devdata(class_dev);
4309         ssize_t l = 0;
4310
4311         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4312         return l;
4313 }
4314
4315 CLASS_DEVICE_ATTR(default_blksize, S_IRUGO, st_defblk_show, NULL);
4316
4317 static ssize_t st_defdensity_show(struct class_device *class_dev, char *buf)
4318 {
4319         struct st_modedef *STm = (struct st_modedef *)class_get_devdata(class_dev);
4320         ssize_t l = 0;
4321         char *fmt;
4322
4323         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4324         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4325         return l;
4326 }
4327
4328 CLASS_DEVICE_ATTR(default_density, S_IRUGO, st_defdensity_show, NULL);
4329
4330 static ssize_t st_defcompression_show(struct class_device *class_dev, char *buf)
4331 {
4332         struct st_modedef *STm = (struct st_modedef *)class_get_devdata(class_dev);
4333         ssize_t l = 0;
4334
4335         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4336         return l;
4337 }
4338
4339 CLASS_DEVICE_ATTR(default_compression, S_IRUGO, st_defcompression_show, NULL);
4340
4341 static int do_create_class_files(struct scsi_tape *STp, int dev_num, int mode)
4342 {
4343         int i, rew, error;
4344         char name[10];
4345         struct class_device *st_class_member;
4346
4347         for (rew=0; rew < 2; rew++) {
4348                 /* Make sure that the minor numbers corresponding to the four
4349                    first modes always get the same names */
4350                 i = mode << (4 - ST_NBR_MODE_BITS);
4351                 snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4352                          STp->disk->disk_name, st_formats[i]);
4353                 st_class_member =
4354                         class_device_create(st_sysfs_class, NULL,
4355                                             MKDEV(SCSI_TAPE_MAJOR,
4356                                                   TAPE_MINOR(dev_num, mode, rew)),
4357                                             &STp->device->sdev_gendev, "%s", name);
4358                 if (IS_ERR(st_class_member)) {
4359                         printk(KERN_WARNING "st%d: class_device_create failed\n",
4360                                dev_num);
4361                         error = PTR_ERR(st_class_member);
4362                         goto out;
4363                 }
4364                 class_set_devdata(st_class_member, &STp->modes[mode]);
4365
4366                 error = class_device_create_file(st_class_member,
4367                                                &class_device_attr_defined);
4368                 if (error) goto out;
4369                 error = class_device_create_file(st_class_member,
4370                                             &class_device_attr_default_blksize);
4371                 if (error) goto out;
4372                 error = class_device_create_file(st_class_member,
4373                                             &class_device_attr_default_density);
4374                 if (error) goto out;
4375                 error = class_device_create_file(st_class_member,
4376                                         &class_device_attr_default_compression);
4377                 if (error) goto out;
4378
4379                 if (mode == 0 && rew == 0) {
4380                         error = sysfs_create_link(&STp->device->sdev_gendev.kobj,
4381                                                   &st_class_member->kobj,
4382                                                   "tape");
4383                         if (error) {
4384                                 printk(KERN_ERR
4385                                        "st%d: Can't create sysfs link from SCSI device.\n",
4386                                        dev_num);
4387                                 goto out;
4388                         }
4389                 }
4390         }
4391
4392         return 0;
4393
4394 out:
4395         return error;
4396 }
4397
4398 /* The following functions may be useful for a larger audience. */
4399 static int sgl_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
4400                               unsigned long uaddr, size_t count, int rw)
4401 {
4402         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4403         unsigned long start = uaddr >> PAGE_SHIFT;
4404         const int nr_pages = end - start;
4405         int res, i, j;
4406         struct page **pages;
4407
4408         /* User attempted Overflow! */
4409         if ((uaddr + count) < uaddr)
4410                 return -EINVAL;
4411
4412         /* Too big */
4413         if (nr_pages > max_pages)
4414                 return -ENOMEM;
4415
4416         /* Hmm? */
4417         if (count == 0)
4418                 return 0;
4419
4420         if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4421                 return -ENOMEM;
4422
4423         /* Try to fault in all of the necessary pages */
4424         down_read(&current->mm->mmap_sem);
4425         /* rw==READ means read from drive, write into memory area */
4426         res = get_user_pages(
4427                 current,
4428                 current->mm,
4429                 uaddr,
4430                 nr_pages,
4431                 rw == READ,
4432                 0, /* don't force */
4433                 pages,
4434                 NULL);
4435         up_read(&current->mm->mmap_sem);
4436
4437         /* Errors and no page mapped should return here */
4438         if (res < nr_pages)
4439                 goto out_unmap;
4440
4441         for (i=0; i < nr_pages; i++) {
4442                 /* FIXME: flush superflous for rw==READ,
4443                  * probably wrong function for rw==WRITE
4444                  */
4445                 flush_dcache_page(pages[i]);
4446         }
4447
4448         /* Populate the scatter/gather list */
4449         sgl[0].page = pages[0];
4450         sgl[0].offset = uaddr & ~PAGE_MASK;
4451         if (nr_pages > 1) {
4452                 sgl[0].length = PAGE_SIZE - sgl[0].offset;
4453                 count -= sgl[0].length;
4454                 for (i=1; i < nr_pages ; i++) {
4455                         sgl[i].offset = 0;
4456                         sgl[i].page = pages[i];
4457                         sgl[i].length = count < PAGE_SIZE ? count : PAGE_SIZE;
4458                         count -= PAGE_SIZE;
4459                 }
4460         }
4461         else {
4462                 sgl[0].length = count;
4463         }
4464
4465         kfree(pages);
4466         return nr_pages;
4467
4468  out_unmap:
4469         if (res > 0) {
4470                 for (j=0; j < res; j++)
4471                         page_cache_release(pages[j]);
4472                 res = 0;
4473         }
4474         kfree(pages);
4475         return res;
4476 }
4477
4478
4479 /* And unmap them... */
4480 static int sgl_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
4481                                 int dirtied)
4482 {
4483         int i;
4484
4485         for (i=0; i < nr_pages; i++) {
4486                 struct page *page = sgl[i].page;
4487
4488                 if (dirtied)
4489                         SetPageDirty(page);
4490                 /* FIXME: cache flush missing for rw==READ
4491                  * FIXME: call the correct reference counting function
4492                  */
4493                 page_cache_release(page);
4494         }
4495
4496         return 0;
4497 }