drivers/scsi/scsi_error.c

   1 /*
   2  *  scsi_error.c Copyright (C) 1997 Eric Youngdale
   3  *
   4  *  SCSI error/timeout handling
   5  *      Initial versions: Eric Youngdale.  Based upon conversations with
   6  *                        Leonard Zubkoff and David Miller at Linux Expo,
   7  *                        ideas originating from all over the place.
   8  *
   9  *      Restructured scsi_unjam_host and associated functions.
  10  *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  11  *
  12  *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
  13  *      minor  cleanups.
  14  *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/timer.h>
  20 #include <linux/string.h>
  21 #include <linux/kernel.h>
  22 #include <linux/freezer.h>
  23 #include <linux/kthread.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/delay.h>
  27
  28 #include <scsi/scsi.h>
  29 #include <scsi/scsi_cmnd.h>
  30 #include <scsi/scsi_dbg.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_eh.h>
  33 #include <scsi/scsi_transport.h>
  34 #include <scsi/scsi_host.h>
  35 #include <scsi/scsi_ioctl.h>
  36
  37 #include "scsi_priv.h"
  38 #include "scsi_logging.h"
  39 #include "scsi_transport_api.h"
  40
  41 #define SENSE_TIMEOUT           (10*HZ)
  42
  43 /*
  44  * These should *probably* be handled by the host itself.
  45  * Since it is allowed to sleep, it probably should.
  46  */
  47 #define BUS_RESET_SETTLE_TIME   (10)
  48 #define HOST_RESET_SETTLE_TIME  (10)
  49
  50 /* called with shost->host_lock held */
  51 void scsi_eh_wakeup(struct Scsi_Host *shost)
  52 {
  53         if (shost->host_busy == shost->host_failed) {
  54                 wake_up_process(shost->ehandler);
  55                 SCSI_LOG_ERROR_RECOVERY(5,
  56                                 printk("Waking error handler thread\n"));
  57         }
  58 }
  59
  60 /**
  61  * scsi_schedule_eh - schedule EH for SCSI host
  62  * @shost:      SCSI host to invoke error handling on.
  63  *
  64  * Schedule SCSI EH without scmd.
  65  */
  66 void scsi_schedule_eh(struct Scsi_Host *shost)
  67 {
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(shost->host_lock, flags);
  71
  72         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  73             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  74                 shost->host_eh_scheduled++;
  75                 scsi_eh_wakeup(shost);
  76         }
  77
  78         spin_unlock_irqrestore(shost->host_lock, flags);
  79 }
  80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  81
  82 /**
  83  * scsi_eh_scmd_add - add scsi cmd to error handling.
  84  * @scmd:       scmd to run eh on.
  85  * @eh_flag:    optional SCSI_EH flag.
  86  *
  87  * Return value:
  88  *      0 on failure.
  89  */
  90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  91 {
  92         struct Scsi_Host *shost = scmd->device->host;
  93         unsigned long flags;
  94         int ret = 0;
  95
  96         if (!shost->ehandler)
  97                 return 0;
  98
  99         spin_lock_irqsave(shost->host_lock, flags);
 100         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 101                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 102                         goto out_unlock;
 103
 104         ret = 1;
 105         scmd->eh_eflags |= eh_flag;
 106         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 107         shost->host_failed++;
 108         scsi_eh_wakeup(shost);
 109  out_unlock:
 110         spin_unlock_irqrestore(shost->host_lock, flags);
 111         return ret;
 112 }
 113
 114 /**
 115  * scsi_times_out - Timeout function for normal scsi commands.
 116  * @req:        request that is timing out.
 117  *
 118  * Notes:
 119  *     We do not need to lock this.  There is the potential for a race
 120  *     only in that the normal completion handling might run, but if the
 121  *     normal completion function determines that the timer has already
 122  *     fired, then it mustn't do anything.
 123  */
 124 enum blk_eh_timer_return scsi_times_out(struct request *req)
 125 {
 126         struct scsi_cmnd *scmd = req->special;
 127         enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
 128         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 129
 130         scsi_log_completion(scmd, TIMEOUT_ERROR);
 131
 132         if (scmd->device->host->transportt->eh_timed_out)
 133                 eh_timed_out = scmd->device->host->transportt->eh_timed_out;
 134         else if (scmd->device->host->hostt->eh_timed_out)
 135                 eh_timed_out = scmd->device->host->hostt->eh_timed_out;
 136         else
 137                 eh_timed_out = NULL;
 138
 139         if (eh_timed_out)
 140                 rtn = eh_timed_out(scmd);
 141                 switch (rtn) {
 142                 case BLK_EH_NOT_HANDLED:
 143                         break;
 144                 default:
 145                         return rtn;
 146                 }
 147
 148         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 149                 scmd->result |= DID_TIME_OUT << 16;
 150                 return BLK_EH_HANDLED;
 151         }
 152
 153         return BLK_EH_NOT_HANDLED;
 154 }
 155
 156 /**
 157  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 158  * @sdev:       Device on which we are performing recovery.
 159  *
 160  * Description:
 161  *     We block until the host is out of error recovery, and then check to
 162  *     see whether the host or the device is offline.
 163  *
 164  * Return value:
 165  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 166  */
 167 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 168 {
 169         int online;
 170
 171         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 172
 173         online = scsi_device_online(sdev);
 174
 175         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
 176                                           online));
 177
 178         return online;
 179 }
 180 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 181
 182 #ifdef CONFIG_SCSI_LOGGING
 183 /**
 184  * scsi_eh_prt_fail_stats - Log info on failures.
 185  * @shost:      scsi host being recovered.
 186  * @work_q:     Queue of scsi cmds to process.
 187  */
 188 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 189                                           struct list_head *work_q)
 190 {
 191         struct scsi_cmnd *scmd;
 192         struct scsi_device *sdev;
 193         int total_failures = 0;
 194         int cmd_failed = 0;
 195         int cmd_cancel = 0;
 196         int devices_failed = 0;
 197
 198         shost_for_each_device(sdev, shost) {
 199                 list_for_each_entry(scmd, work_q, eh_entry) {
 200                         if (scmd->device == sdev) {
 201                                 ++total_failures;
 202                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 203                                         ++cmd_cancel;
 204                                 else
 205                                         ++cmd_failed;
 206                         }
 207                 }
 208
 209                 if (cmd_cancel || cmd_failed) {
 210                         SCSI_LOG_ERROR_RECOVERY(3,
 211                                 sdev_printk(KERN_INFO, sdev,
 212                                             "%s: cmds failed: %d, cancel: %d\n",
 213                                             __func__, cmd_failed,
 214                                             cmd_cancel));
 215                         cmd_cancel = 0;
 216                         cmd_failed = 0;
 217                         ++devices_failed;
 218                 }
 219         }
 220
 221         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 222                                           " devices require eh work\n",
 223                                   total_failures, devices_failed));
 224 }
 225 #endif
 226
 227 /**
 228  * scsi_check_sense - Examine scsi cmd sense
 229  * @scmd:       Cmd to have sense checked.
 230  *
 231  * Return value:
 232  *      SUCCESS or FAILED or NEEDS_RETRY
 233  *
 234  * Notes:
 235  *      When a deferred error is detected the current command has
 236  *      not been executed and needs retrying.
 237  */
 238 static int scsi_check_sense(struct scsi_cmnd *scmd)
 239 {
 240         struct scsi_device *sdev = scmd->device;
 241         struct scsi_sense_hdr sshdr;
 242
 243         if (! scsi_command_normalize_sense(scmd, &sshdr))
 244                 return FAILED;  /* no valid sense data */
 245
 246         if (scsi_sense_is_deferred(&sshdr))
 247                 return NEEDS_RETRY;
 248
 249         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
 250                         sdev->scsi_dh_data->scsi_dh->check_sense) {
 251                 int rc;
 252
 253                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
 254                 if (rc != SCSI_RETURN_NOT_HANDLED)
 255                         return rc;
 256                 /* handler does not care. Drop down to default handling */
 257         }
 258
 259         /*
 260          * Previous logic looked for FILEMARK, EOM or ILI which are
 261          * mainly associated with tapes and returned SUCCESS.
 262          */
 263         if (sshdr.response_code == 0x70) {
 264                 /* fixed format */
 265                 if (scmd->sense_buffer[2] & 0xe0)
 266                         return SUCCESS;
 267         } else {
 268                 /*
 269                  * descriptor format: look for "stream commands sense data
 270                  * descriptor" (see SSC-3). Assume single sense data
 271                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 272                  */
 273                 if ((sshdr.additional_length > 3) &&
 274                     (scmd->sense_buffer[8] == 0x4) &&
 275                     (scmd->sense_buffer[11] & 0xe0))
 276                         return SUCCESS;
 277         }
 278
 279         switch (sshdr.sense_key) {
 280         case NO_SENSE:
 281                 return SUCCESS;
 282         case RECOVERED_ERROR:
 283                 return /* soft_error */ SUCCESS;
 284
 285         case ABORTED_COMMAND:
 286                 if (sshdr.asc == 0x10) /* DIF */
 287                         return SUCCESS;
 288
 289                 return NEEDS_RETRY;
 290         case NOT_READY:
 291         case UNIT_ATTENTION:
 292                 /*
 293                  * if we are expecting a cc/ua because of a bus reset that we
 294                  * performed, treat this just as a retry.  otherwise this is
 295                  * information that we should pass up to the upper-level driver
 296                  * so that we can deal with it there.
 297                  */
 298                 if (scmd->device->expecting_cc_ua) {
 299                         scmd->device->expecting_cc_ua = 0;
 300                         return NEEDS_RETRY;
 301                 }
 302                 /*
 303                  * if the device is in the process of becoming ready, we
 304                  * should retry.
 305                  */
 306                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 307                         return NEEDS_RETRY;
 308                 /*
 309                  * if the device is not started, we need to wake
 310                  * the error handler to start the motor
 311                  */
 312                 if (scmd->device->allow_restart &&
 313                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 314                         return FAILED;
 315                 return SUCCESS;
 316
 317                 /* these three are not supported */
 318         case COPY_ABORTED:
 319         case VOLUME_OVERFLOW:
 320         case MISCOMPARE:
 321                 return SUCCESS;
 322
 323         case MEDIUM_ERROR:
 324                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 325                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 326                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 327                         return SUCCESS;
 328                 }
 329                 return NEEDS_RETRY;
 330
 331         case HARDWARE_ERROR:
 332                 if (scmd->device->retry_hwerror)
 333                         return ADD_TO_MLQUEUE;
 334                 else
 335                         return SUCCESS;
 336
 337         case ILLEGAL_REQUEST:
 338         case BLANK_CHECK:
 339         case DATA_PROTECT:
 340         default:
 341                 return SUCCESS;
 342         }
 343 }
 344
 345 /**
 346  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 347  * @scmd:       SCSI cmd to examine.
 348  *
 349  * Notes:
 350  *    This is *only* called when we are examining the status of commands
 351  *    queued during error recovery.  the main difference here is that we
 352  *    don't allow for the possibility of retries here, and we are a lot
 353  *    more restrictive about what we consider acceptable.
 354  */
 355 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 356 {
 357         /*
 358          * first check the host byte, to see if there is anything in there
 359          * that would indicate what we need to do.
 360          */
 361         if (host_byte(scmd->result) == DID_RESET) {
 362                 /*
 363                  * rats.  we are already in the error handler, so we now
 364                  * get to try and figure out what to do next.  if the sense
 365                  * is valid, we have a pretty good idea of what to do.
 366                  * if not, we mark it as FAILED.
 367                  */
 368                 return scsi_check_sense(scmd);
 369         }
 370         if (host_byte(scmd->result) != DID_OK)
 371                 return FAILED;
 372
 373         /*
 374          * next, check the message byte.
 375          */
 376         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 377                 return FAILED;
 378
 379         /*
 380          * now, check the status byte to see if this indicates
 381          * anything special.
 382          */
 383         switch (status_byte(scmd->result)) {
 384         case GOOD:
 385         case COMMAND_TERMINATED:
 386                 return SUCCESS;
 387         case CHECK_CONDITION:
 388                 return scsi_check_sense(scmd);
 389         case CONDITION_GOOD:
 390         case INTERMEDIATE_GOOD:
 391         case INTERMEDIATE_C_GOOD:
 392                 /*
 393                  * who knows?  FIXME(eric)
 394                  */
 395                 return SUCCESS;
 396         case BUSY:
 397         case QUEUE_FULL:
 398         case RESERVATION_CONFLICT:
 399         default:
 400                 return FAILED;
 401         }
 402         return FAILED;
 403 }
 404
 405 /**
 406  * scsi_eh_done - Completion function for error handling.
 407  * @scmd:       Cmd that is done.
 408  */
 409 static void scsi_eh_done(struct scsi_cmnd *scmd)
 410 {
 411         struct completion     *eh_action;
 412
 413         SCSI_LOG_ERROR_RECOVERY(3,
 414                 printk("%s scmd: %p result: %x\n",
 415                         __func__, scmd, scmd->result));
 416
 417         eh_action = scmd->device->host->eh_action;
 418         if (eh_action)
 419                 complete(eh_action);
 420 }
 421
 422 /**
 423  * scsi_try_host_reset - ask host adapter to reset itself
 424  * @scmd:       SCSI cmd to send hsot reset.
 425  */
 426 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 427 {
 428         unsigned long flags;
 429         int rtn;
 430
 431         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
 432                                           __func__));
 433
 434         if (!scmd->device->host->hostt->eh_host_reset_handler)
 435                 return FAILED;
 436
 437         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
 438
 439         if (rtn == SUCCESS) {
 440                 if (!scmd->device->host->hostt->skip_settle_delay)
 441                         ssleep(HOST_RESET_SETTLE_TIME);
 442                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 443                 scsi_report_bus_reset(scmd->device->host,
 444                                       scmd_channel(scmd));
 445                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 446         }
 447
 448         return rtn;
 449 }
 450
 451 /**
 452  * scsi_try_bus_reset - ask host to perform a bus reset
 453  * @scmd:       SCSI cmd to send bus reset.
 454  */
 455 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 456 {
 457         unsigned long flags;
 458         int rtn;
 459
 460         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
 461                                           __func__));
 462
 463         if (!scmd->device->host->hostt->eh_bus_reset_handler)
 464                 return FAILED;
 465
 466         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
 467
 468         if (rtn == SUCCESS) {
 469                 if (!scmd->device->host->hostt->skip_settle_delay)
 470                         ssleep(BUS_RESET_SETTLE_TIME);
 471                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 472                 scsi_report_bus_reset(scmd->device->host,
 473                                       scmd_channel(scmd));
 474                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 475         }
 476
 477         return rtn;
 478 }
 479
 480 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 481 {
 482         sdev->was_reset = 1;
 483         sdev->expecting_cc_ua = 1;
 484 }
 485
 486 /**
 487  * scsi_try_target_reset - Ask host to perform a target reset
 488  * @scmd:       SCSI cmd used to send a target reset
 489  *
 490  * Notes:
 491  *    There is no timeout for this operation.  if this operation is
 492  *    unreliable for a given host, then the host itself needs to put a
 493  *    timer on it, and set the host back to a consistent state prior to
 494  *    returning.
 495  */
 496 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 497 {
 498         unsigned long flags;
 499         int rtn;
 500
 501         if (!scmd->device->host->hostt->eh_target_reset_handler)
 502                 return FAILED;
 503
 504         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
 505         if (rtn == SUCCESS) {
 506                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 507                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 508                                           __scsi_report_device_reset);
 509                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 510         }
 511
 512         return rtn;
 513 }
 514
 515 /**
 516  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 517  * @scmd:       SCSI cmd used to send BDR
 518  *
 519  * Notes:
 520  *    There is no timeout for this operation.  if this operation is
 521  *    unreliable for a given host, then the host itself needs to put a
 522  *    timer on it, and set the host back to a consistent state prior to
 523  *    returning.
 524  */
 525 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 526 {
 527         int rtn;
 528
 529         if (!scmd->device->host->hostt->eh_device_reset_handler)
 530                 return FAILED;
 531
 532         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 533         if (rtn == SUCCESS)
 534                 __scsi_report_device_reset(scmd->device, NULL);
 535         return rtn;
 536 }
 537
 538 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 539 {
 540         if (!scmd->device->host->hostt->eh_abort_handler)
 541                 return FAILED;
 542
 543         return scmd->device->host->hostt->eh_abort_handler(scmd);
 544 }
 545
 546 /**
 547  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 548  * @scmd:       SCSI cmd to abort from Lower Level.
 549  *
 550  * Notes:
 551  *    This function will not return until the user's completion function
 552  *    has been called.  there is no timeout on this operation.  if the
 553  *    author of the low-level driver wishes this operation to be timed,
 554  *    they can provide this facility themselves.  helper functions in
 555  *    scsi_error.c can be supplied to make this easier to do.
 556  */
 557 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 558 {
 559         /*
 560          * scsi_done was called just after the command timed out and before
 561          * we had a chance to process it. (db)
 562          */
 563         if (scmd->serial_number == 0)
 564                 return SUCCESS;
 565         return __scsi_try_to_abort_cmd(scmd);
 566 }
 567
 568 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 569 {
 570         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
 571                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 572                         if (scsi_try_target_reset(scmd) != SUCCESS)
 573                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 574                                         scsi_try_host_reset(scmd);
 575 }
 576
 577 /**
 578  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
 579  * @scmd:       SCSI command structure to hijack
 580  * @ses:        structure to save restore information
 581  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 582  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 583  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 584  *
 585  * This function is used to save a scsi command information before re-execution
 586  * as part of the error recovery process.  If @sense_bytes is 0 the command
 587  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 588  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 589  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 590  */
 591 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 592                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 593 {
 594         struct scsi_device *sdev = scmd->device;
 595
 596         /*
 597          * We need saved copies of a number of fields - this is because
 598          * error handling may need to overwrite these with different values
 599          * to run different commands, and once error handling is complete,
 600          * we will need to restore these values prior to running the actual
 601          * command.
 602          */
 603         ses->cmd_len = scmd->cmd_len;
 604         ses->cmnd = scmd->cmnd;
 605         ses->data_direction = scmd->sc_data_direction;
 606         ses->sdb = scmd->sdb;
 607         ses->next_rq = scmd->request->next_rq;
 608         ses->result = scmd->result;
 609         ses->underflow = scmd->underflow;
 610         ses->prot_op = scmd->prot_op;
 611
 612         scmd->prot_op = SCSI_PROT_NORMAL;
 613         scmd->cmnd = ses->eh_cmnd;
 614         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 615         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 616         scmd->request->next_rq = NULL;
 617
 618         if (sense_bytes) {
 619                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 620                                          sense_bytes);
 621                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 622                             scmd->sdb.length);
 623                 scmd->sdb.table.sgl = &ses->sense_sgl;
 624                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 625                 scmd->sdb.table.nents = 1;
 626                 scmd->cmnd[0] = REQUEST_SENSE;
 627                 scmd->cmnd[4] = scmd->sdb.length;
 628                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 629         } else {
 630                 scmd->sc_data_direction = DMA_NONE;
 631                 if (cmnd) {
 632                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 633                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 634                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 635                 }
 636         }
 637
 638         scmd->underflow = 0;
 639
 640         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 641                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 642                         (sdev->lun << 5 & 0xe0);
 643
 644         /*
 645          * Zero the sense buffer.  The scsi spec mandates that any
 646          * untransferred sense data should be interpreted as being zero.
 647          */
 648         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 649 }
 650 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 651
 652 /**
 653  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
 654  * @scmd:       SCSI command structure to restore
 655  * @ses:        saved information from a coresponding call to scsi_prep_eh_cmnd
 656  *
 657  * Undo any damage done by above scsi_prep_eh_cmnd().
 658  */
 659 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 660 {
 661         /*
 662          * Restore original data
 663          */
 664         scmd->cmd_len = ses->cmd_len;
 665         scmd->cmnd = ses->cmnd;
 666         scmd->sc_data_direction = ses->data_direction;
 667         scmd->sdb = ses->sdb;
 668         scmd->request->next_rq = ses->next_rq;
 669         scmd->result = ses->result;
 670         scmd->underflow = ses->underflow;
 671         scmd->prot_op = ses->prot_op;
 672 }
 673 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 674
 675 /**
 676  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
 677  * @scmd:       SCSI command structure to hijack
 678  * @cmnd:       CDB to send
 679  * @cmnd_size:  size in bytes of @cmnd
 680  * @timeout:    timeout for this request
 681  * @sense_bytes: size of sense data to copy or 0
 682  *
 683  * This function is used to send a scsi command down to a target device
 684  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 685  *
 686  * Return value:
 687  *    SUCCESS or FAILED or NEEDS_RETRY
 688  */
 689 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 690                              int cmnd_size, int timeout, unsigned sense_bytes)
 691 {
 692         struct scsi_device *sdev = scmd->device;
 693         struct Scsi_Host *shost = sdev->host;
 694         DECLARE_COMPLETION_ONSTACK(done);
 695         unsigned long timeleft;
 696         unsigned long flags;
 697         struct scsi_eh_save ses;
 698         int rtn;
 699
 700         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
 701         shost->eh_action = &done;
 702
 703         spin_lock_irqsave(shost->host_lock, flags);
 704         scsi_log_send(scmd);
 705         shost->hostt->queuecommand(scmd, scsi_eh_done);
 706         spin_unlock_irqrestore(shost->host_lock, flags);
 707
 708         timeleft = wait_for_completion_timeout(&done, timeout);
 709
 710         shost->eh_action = NULL;
 711
 712         scsi_log_completion(scmd, SUCCESS);
 713
 714         SCSI_LOG_ERROR_RECOVERY(3,
 715                 printk("%s: scmd: %p, timeleft: %ld\n",
 716                         __func__, scmd, timeleft));
 717
 718         /*
 719          * If there is time left scsi_eh_done got called, and we will
 720          * examine the actual status codes to see whether the command
 721          * actually did complete normally, else tell the host to forget
 722          * about this command.
 723          */
 724         if (timeleft) {
 725                 rtn = scsi_eh_completed_normally(scmd);
 726                 SCSI_LOG_ERROR_RECOVERY(3,
 727                         printk("%s: scsi_eh_completed_normally %x\n",
 728                                __func__, rtn));
 729
 730                 switch (rtn) {
 731                 case SUCCESS:
 732                 case NEEDS_RETRY:
 733                 case FAILED:
 734                         break;
 735                 default:
 736                         rtn = FAILED;
 737                         break;
 738                 }
 739         } else {
 740                 scsi_abort_eh_cmnd(scmd);
 741                 rtn = FAILED;
 742         }
 743
 744         scsi_eh_restore_cmnd(scmd, &ses);
 745         return rtn;
 746 }
 747
 748 /**
 749  * scsi_request_sense - Request sense data from a particular target.
 750  * @scmd:       SCSI cmd for request sense.
 751  *
 752  * Notes:
 753  *    Some hosts automatically obtain this information, others require
 754  *    that we obtain it on our own. This function will *not* return until
 755  *    the command either times out, or it completes.
 756  */
 757 static int scsi_request_sense(struct scsi_cmnd *scmd)
 758 {
 759         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 760 }
 761
 762 /**
 763  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 764  * @scmd:       Original SCSI cmd that eh has finished.
 765  * @done_q:     Queue for processed commands.
 766  *
 767  * Notes:
 768  *    We don't want to use the normal command completion while we are are
 769  *    still handling errors - it may cause other commands to be queued,
 770  *    and that would disturb what we are doing.  Thus we really want to
 771  *    keep a list of pending commands for final completion, and once we
 772  *    are ready to leave error handling we handle completion for real.
 773  */
 774 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 775 {
 776         scmd->device->host->host_failed--;
 777         scmd->eh_eflags = 0;
 778         list_move_tail(&scmd->eh_entry, done_q);
 779 }
 780 EXPORT_SYMBOL(scsi_eh_finish_cmd);
 781
 782 /**
 783  * scsi_eh_get_sense - Get device sense data.
 784  * @work_q:     Queue of commands to process.
 785  * @done_q:     Queue of processed commands.
 786  *
 787  * Description:
 788  *    See if we need to request sense information.  if so, then get it
 789  *    now, so we have a better idea of what to do.
 790  *
 791  * Notes:
 792  *    This has the unfortunate side effect that if a shost adapter does
 793  *    not automatically request sense information, we end up shutting
 794  *    it down before we request it.
 795  *
 796  *    All drivers should request sense information internally these days,
 797  *    so for now all I have to say is tough noogies if you end up in here.
 798  *
 799  *    XXX: Long term this code should go away, but that needs an audit of
 800  *         all LLDDs first.
 801  */
 802 int scsi_eh_get_sense(struct list_head *work_q,
 803                       struct list_head *done_q)
 804 {
 805         struct scsi_cmnd *scmd, *next;
 806         int rtn;
 807
 808         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 809                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 810                     SCSI_SENSE_VALID(scmd))
 811                         continue;
 812
 813                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 814                                                   "%s: requesting sense\n",
 815                                                   current->comm));
 816                 rtn = scsi_request_sense(scmd);
 817                 if (rtn != SUCCESS)
 818                         continue;
 819
 820                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 821                                                   " result %x\n", scmd,
 822                                                   scmd->result));
 823                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 824
 825                 rtn = scsi_decide_disposition(scmd);
 826
 827                 /*
 828                  * if the result was normal, then just pass it along to the
 829                  * upper level.
 830                  */
 831                 if (rtn == SUCCESS)
 832                         /* we don't want this command reissued, just
 833                          * finished with the sense data, so set
 834                          * retries to the max allowed to ensure it
 835                          * won't get reissued */
 836                         scmd->retries = scmd->allowed;
 837                 else if (rtn != NEEDS_RETRY)
 838                         continue;
 839
 840                 scsi_eh_finish_cmd(scmd, done_q);
 841         }
 842
 843         return list_empty(work_q);
 844 }
 845 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 846
 847 /**
 848  * scsi_eh_tur - Send TUR to device.
 849  * @scmd:       &scsi_cmnd to send TUR
 850  *
 851  * Return value:
 852  *    0 - Device is ready. 1 - Device NOT ready.
 853  */
 854 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 855 {
 856         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 857         int retry_cnt = 1, rtn;
 858
 859 retry_tur:
 860         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 861
 862         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 863                 __func__, scmd, rtn));
 864
 865         switch (rtn) {
 866         case NEEDS_RETRY:
 867                 if (retry_cnt--)
 868                         goto retry_tur;
 869                 /*FALLTHRU*/
 870         case SUCCESS:
 871                 return 0;
 872         default:
 873                 return 1;
 874         }
 875 }
 876
 877 /**
 878  * scsi_eh_abort_cmds - abort pending commands.
 879  * @work_q:     &list_head for pending commands.
 880  * @done_q:     &list_head for processed commands.
 881  *
 882  * Decription:
 883  *    Try and see whether or not it makes sense to try and abort the
 884  *    running command.  This only works out to be the case if we have one
 885  *    command that has timed out.  If the command simply failed, it makes
 886  *    no sense to try and abort the command, since as far as the shost
 887  *    adapter is concerned, it isn't running.
 888  */
 889 static int scsi_eh_abort_cmds(struct list_head *work_q,
 890                               struct list_head *done_q)
 891 {
 892         struct scsi_cmnd *scmd, *next;
 893         int rtn;
 894
 895         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 896                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 897                         continue;
 898                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 899                                                   "0x%p\n", current->comm,
 900                                                   scmd));
 901                 rtn = scsi_try_to_abort_cmd(scmd);
 902                 if (rtn == SUCCESS) {
 903                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 904                         if (!scsi_device_online(scmd->device) ||
 905                             !scsi_eh_tur(scmd)) {
 906                                 scsi_eh_finish_cmd(scmd, done_q);
 907                         }
 908
 909                 } else
 910                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 911                                                           " cmd failed:"
 912                                                           "0x%p\n",
 913                                                           current->comm,
 914                                                           scmd));
 915         }
 916
 917         return list_empty(work_q);
 918 }
 919
 920 /**
 921  * scsi_eh_try_stu - Send START_UNIT to device.
 922  * @scmd:       &scsi_cmnd to send START_UNIT
 923  *
 924  * Return value:
 925  *    0 - Device is ready. 1 - Device NOT ready.
 926  */
 927 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 928 {
 929         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 930
 931         if (scmd->device->allow_restart) {
 932                 int i, rtn = NEEDS_RETRY;
 933
 934                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
 935                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
 936                                                 scmd->device->timeout, 0);
 937
 938                 if (rtn == SUCCESS)
 939                         return 0;
 940         }
 941
 942         return 1;
 943 }
 944
 945  /**
 946  * scsi_eh_stu - send START_UNIT if needed
 947  * @shost:      &scsi host being recovered.
 948  * @work_q:     &list_head for pending commands.
 949  * @done_q:     &list_head for processed commands.
 950  *
 951  * Notes:
 952  *    If commands are failing due to not ready, initializing command required,
 953  *      try revalidating the device, which will end up sending a start unit.
 954  */
 955 static int scsi_eh_stu(struct Scsi_Host *shost,
 956                               struct list_head *work_q,
 957                               struct list_head *done_q)
 958 {
 959         struct scsi_cmnd *scmd, *stu_scmd, *next;
 960         struct scsi_device *sdev;
 961
 962         shost_for_each_device(sdev, shost) {
 963                 stu_scmd = NULL;
 964                 list_for_each_entry(scmd, work_q, eh_entry)
 965                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 966                             scsi_check_sense(scmd) == FAILED ) {
 967                                 stu_scmd = scmd;
 968                                 break;
 969                         }
 970
 971                 if (!stu_scmd)
 972                         continue;
 973
 974                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 975                                                   " 0x%p\n", current->comm, sdev));
 976
 977                 if (!scsi_eh_try_stu(stu_scmd)) {
 978                         if (!scsi_device_online(sdev) ||
 979                             !scsi_eh_tur(stu_scmd)) {
 980                                 list_for_each_entry_safe(scmd, next,
 981                                                           work_q, eh_entry) {
 982                                         if (scmd->device == sdev)
 983                                                 scsi_eh_finish_cmd(scmd, done_q);
 984                                 }
 985                         }
 986                 } else {
 987                         SCSI_LOG_ERROR_RECOVERY(3,
 988                                                 printk("%s: START_UNIT failed to sdev:"
 989                                                        " 0x%p\n", current->comm, sdev));
 990                 }
 991         }
 992
 993         return list_empty(work_q);
 994 }
 995
 996
 997 /**
 998  * scsi_eh_bus_device_reset - send bdr if needed
 999  * @shost:      scsi host being recovered.
1000  * @work_q:     &list_head for pending commands.
1001  * @done_q:     &list_head for processed commands.
1002  *
1003  * Notes:
1004  *    Try a bus device reset.  Still, look to see whether we have multiple
1005  *    devices that are jammed or not - if we have multiple devices, it
1006  *    makes no sense to try bus_device_reset - we really would need to try
1007  *    a bus_reset instead.
1008  */
1009 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1010                                     struct list_head *work_q,
1011                                     struct list_head *done_q)
1012 {
1013         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1014         struct scsi_device *sdev;
1015         int rtn;
1016
1017         shost_for_each_device(sdev, shost) {
1018                 bdr_scmd = NULL;
1019                 list_for_each_entry(scmd, work_q, eh_entry)
1020                         if (scmd->device == sdev) {
1021                                 bdr_scmd = scmd;
1022                                 break;
1023                         }
1024
1025                 if (!bdr_scmd)
1026                         continue;
1027
1028                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1029                                                   " 0x%p\n", current->comm,
1030                                                   sdev));
1031                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1032                 if (rtn == SUCCESS) {
1033                         if (!scsi_device_online(sdev) ||
1034                             !scsi_eh_tur(bdr_scmd)) {
1035                                 list_for_each_entry_safe(scmd, next,
1036                                                          work_q, eh_entry) {
1037                                         if (scmd->device == sdev)
1038                                                 scsi_eh_finish_cmd(scmd,
1039                                                                    done_q);
1040                                 }
1041                         }
1042                 } else {
1043                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1044                                                           " failed sdev:"
1045                                                           "0x%p\n",
1046                                                           current->comm,
1047                                                            sdev));
1048                 }
1049         }
1050
1051         return list_empty(work_q);
1052 }
1053
1054 /**
1055  * scsi_eh_target_reset - send target reset if needed
1056  * @shost:      scsi host being recovered.
1057  * @work_q:     &list_head for pending commands.
1058  * @done_q:     &list_head for processed commands.
1059  *
1060  * Notes:
1061  *    Try a target reset.
1062  */
1063 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1064                                 struct list_head *work_q,
1065                                 struct list_head *done_q)
1066 {
1067         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1068         unsigned int id;
1069         int rtn;
1070
1071         for (id = 0; id <= shost->max_id; id++) {
1072                 tgtr_scmd = NULL;
1073                 list_for_each_entry(scmd, work_q, eh_entry) {
1074                         if (id == scmd_id(scmd)) {
1075                                 tgtr_scmd = scmd;
1076                                 break;
1077                         }
1078                 }
1079                 if (!tgtr_scmd)
1080                         continue;
1081
1082                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1083                                                   "to target %d\n",
1084                                                   current->comm, id));
1085                 rtn = scsi_try_target_reset(tgtr_scmd);
1086                 if (rtn == SUCCESS) {
1087                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1088                                 if (id == scmd_id(scmd))
1089                                         if (!scsi_device_online(scmd->device) ||
1090                                             !scsi_eh_tur(tgtr_scmd))
1091                                                 scsi_eh_finish_cmd(scmd,
1092                                                                    done_q);
1093                         }
1094                 } else
1095                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1096                                                           " failed target: "
1097                                                           "%d\n",
1098                                                           current->comm, id));
1099         }
1100
1101         return list_empty(work_q);
1102 }
1103
1104 /**
1105  * scsi_eh_bus_reset - send a bus reset
1106  * @shost:      &scsi host being recovered.
1107  * @work_q:     &list_head for pending commands.
1108  * @done_q:     &list_head for processed commands.
1109  */
1110 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1111                              struct list_head *work_q,
1112                              struct list_head *done_q)
1113 {
1114         struct scsi_cmnd *scmd, *chan_scmd, *next;
1115         unsigned int channel;
1116         int rtn;
1117
1118         /*
1119          * we really want to loop over the various channels, and do this on
1120          * a channel by channel basis.  we should also check to see if any
1121          * of the failed commands are on soft_reset devices, and if so, skip
1122          * the reset.
1123          */
1124
1125         for (channel = 0; channel <= shost->max_channel; channel++) {
1126                 chan_scmd = NULL;
1127                 list_for_each_entry(scmd, work_q, eh_entry) {
1128                         if (channel == scmd_channel(scmd)) {
1129                                 chan_scmd = scmd;
1130                                 break;
1131                                 /*
1132                                  * FIXME add back in some support for
1133                                  * soft_reset devices.
1134                                  */
1135                         }
1136                 }
1137
1138                 if (!chan_scmd)
1139                         continue;
1140                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1141                                                   " %d\n", current->comm,
1142                                                   channel));
1143                 rtn = scsi_try_bus_reset(chan_scmd);
1144                 if (rtn == SUCCESS) {
1145                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1146                                 if (channel == scmd_channel(scmd))
1147                                         if (!scsi_device_online(scmd->device) ||
1148                                             !scsi_eh_tur(scmd))
1149                                                 scsi_eh_finish_cmd(scmd,
1150                                                                    done_q);
1151                         }
1152                 } else {
1153                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1154                                                           " failed chan: %d\n",
1155                                                           current->comm,
1156                                                           channel));
1157                 }
1158         }
1159         return list_empty(work_q);
1160 }
1161
1162 /**
1163  * scsi_eh_host_reset - send a host reset
1164  * @work_q:     list_head for processed commands.
1165  * @done_q:     list_head for processed commands.
1166  */
1167 static int scsi_eh_host_reset(struct list_head *work_q,
1168                               struct list_head *done_q)
1169 {
1170         struct scsi_cmnd *scmd, *next;
1171         int rtn;
1172
1173         if (!list_empty(work_q)) {
1174                 scmd = list_entry(work_q->next,
1175                                   struct scsi_cmnd, eh_entry);
1176
1177                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1178                                                   , current->comm));
1179
1180                 rtn = scsi_try_host_reset(scmd);
1181                 if (rtn == SUCCESS) {
1182                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1183                                 if (!scsi_device_online(scmd->device) ||
1184                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1185                                     !scsi_eh_tur(scmd))
1186                                         scsi_eh_finish_cmd(scmd, done_q);
1187                         }
1188                 } else {
1189                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1190                                                           " failed\n",
1191                                                           current->comm));
1192                 }
1193         }
1194         return list_empty(work_q);
1195 }
1196
1197 /**
1198  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1199  * @work_q:     list_head for processed commands.
1200  * @done_q:     list_head for processed commands.
1201  */
1202 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1203                                   struct list_head *done_q)
1204 {
1205         struct scsi_cmnd *scmd, *next;
1206
1207         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1208                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1209                             "not ready after error recovery\n");
1210                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1211                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1212                         /*
1213                          * FIXME: Handle lost cmds.
1214                          */
1215                 }
1216                 scsi_eh_finish_cmd(scmd, done_q);
1217         }
1218         return;
1219 }
1220
1221 /**
1222  * scsi_noretry_cmd - determinte if command should be failed fast
1223  * @scmd:       SCSI cmd to examine.
1224  */
1225 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1226 {
1227         switch (host_byte(scmd->result)) {
1228         case DID_OK:
1229                 break;
1230         case DID_BUS_BUSY:
1231                 return blk_failfast_transport(scmd->request);
1232         case DID_PARITY:
1233                 return blk_failfast_dev(scmd->request);
1234         case DID_ERROR:
1235                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1236                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1237                         return 0;
1238                 /* fall through */
1239         case DID_SOFT_ERROR:
1240                 return blk_failfast_driver(scmd->request);
1241         }
1242
1243         switch (status_byte(scmd->result)) {
1244         case CHECK_CONDITION:
1245                 /*
1246                  * assume caller has checked sense and determinted
1247                  * the check condition was retryable.
1248                  */
1249                 return blk_failfast_dev(scmd->request);
1250         }
1251
1252         return 0;
1253 }
1254
1255 /**
1256  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1257  * @scmd:       SCSI cmd to examine.
1258  *
1259  * Notes:
1260  *    This is *only* called when we are examining the status after sending
1261  *    out the actual data command.  any commands that are queued for error
1262  *    recovery (e.g. test_unit_ready) do *not* come through here.
1263  *
1264  *    When this routine returns failed, it means the error handler thread
1265  *    is woken.  In cases where the error code indicates an error that
1266  *    doesn't require the error handler read (i.e. we don't need to
1267  *    abort/reset), this function should return SUCCESS.
1268  */
1269 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1270 {
1271         int rtn;
1272
1273         /*
1274          * if the device is offline, then we clearly just pass the result back
1275          * up to the top level.
1276          */
1277         if (!scsi_device_online(scmd->device)) {
1278                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1279                                                   " as SUCCESS\n",
1280                                                   __func__));
1281                 return SUCCESS;
1282         }
1283
1284         /*
1285          * first check the host byte, to see if there is anything in there
1286          * that would indicate what we need to do.
1287          */
1288         switch (host_byte(scmd->result)) {
1289         case DID_PASSTHROUGH:
1290                 /*
1291                  * no matter what, pass this through to the upper layer.
1292                  * nuke this special code so that it looks like we are saying
1293                  * did_ok.
1294                  */
1295                 scmd->result &= 0xff00ffff;
1296                 return SUCCESS;
1297         case DID_OK:
1298                 /*
1299                  * looks good.  drop through, and check the next byte.
1300                  */
1301                 break;
1302         case DID_NO_CONNECT:
1303         case DID_BAD_TARGET:
1304         case DID_ABORT:
1305                 /*
1306                  * note - this means that we just report the status back
1307                  * to the top level driver, not that we actually think
1308                  * that it indicates SUCCESS.
1309                  */
1310                 return SUCCESS;
1311                 /*
1312                  * when the low level driver returns did_soft_error,
1313                  * it is responsible for keeping an internal retry counter
1314                  * in order to avoid endless loops (db)
1315                  *
1316                  * actually this is a bug in this function here.  we should
1317                  * be mindful of the maximum number of retries specified
1318                  * and not get stuck in a loop.
1319                  */
1320         case DID_SOFT_ERROR:
1321                 goto maybe_retry;
1322         case DID_IMM_RETRY:
1323                 return NEEDS_RETRY;
1324
1325         case DID_REQUEUE:
1326                 return ADD_TO_MLQUEUE;
1327         case DID_TRANSPORT_DISRUPTED:
1328                 /*
1329                  * LLD/transport was disrupted during processing of the IO.
1330                  * The transport class is now blocked/blocking,
1331                  * and the transport will decide what to do with the IO
1332                  * based on its timers and recovery capablilities.
1333                  */
1334                 return ADD_TO_MLQUEUE;
1335         case DID_TRANSPORT_FAILFAST:
1336                 /*
1337                  * The transport decided to failfast the IO (most likely
1338                  * the fast io fail tmo fired), so send IO directly upwards.
1339                  */
1340                 return SUCCESS;
1341         case DID_ERROR:
1342                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1343                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1344                         /*
1345                          * execute reservation conflict processing code
1346                          * lower down
1347                          */
1348                         break;
1349                 /* fallthrough */
1350
1351         case DID_BUS_BUSY:
1352         case DID_PARITY:
1353                 goto maybe_retry;
1354         case DID_TIME_OUT:
1355                 /*
1356                  * when we scan the bus, we get timeout messages for
1357                  * these commands if there is no device available.
1358                  * other hosts report did_no_connect for the same thing.
1359                  */
1360                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1361                      scmd->cmnd[0] == INQUIRY)) {
1362                         return SUCCESS;
1363                 } else {
1364                         return FAILED;
1365                 }
1366         case DID_RESET:
1367                 return SUCCESS;
1368         default:
1369                 return FAILED;
1370         }
1371
1372         /*
1373          * next, check the message byte.
1374          */
1375         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1376                 return FAILED;
1377
1378         /*
1379          * check the status byte to see if this indicates anything special.
1380          */
1381         switch (status_byte(scmd->result)) {
1382         case QUEUE_FULL:
1383                 /*
1384                  * the case of trying to send too many commands to a
1385                  * tagged queueing device.
1386                  */
1387         case BUSY:
1388                 /*
1389                  * device can't talk to us at the moment.  Should only
1390                  * occur (SAM-3) when the task queue is empty, so will cause
1391                  * the empty queue handling to trigger a stall in the
1392                  * device.
1393                  */
1394                 return ADD_TO_MLQUEUE;
1395         case GOOD:
1396         case COMMAND_TERMINATED:
1397         case TASK_ABORTED:
1398                 return SUCCESS;
1399         case CHECK_CONDITION:
1400                 rtn = scsi_check_sense(scmd);
1401                 if (rtn == NEEDS_RETRY)
1402                         goto maybe_retry;
1403                 /* if rtn == FAILED, we have no sense information;
1404                  * returning FAILED will wake the error handler thread
1405                  * to collect the sense and redo the decide
1406                  * disposition */
1407                 return rtn;
1408         case CONDITION_GOOD:
1409         case INTERMEDIATE_GOOD:
1410         case INTERMEDIATE_C_GOOD:
1411         case ACA_ACTIVE:
1412                 /*
1413                  * who knows?  FIXME(eric)
1414                  */
1415                 return SUCCESS;
1416
1417         case RESERVATION_CONFLICT:
1418                 sdev_printk(KERN_INFO, scmd->device,
1419                             "reservation conflict\n");
1420                 return SUCCESS; /* causes immediate i/o error */
1421         default:
1422                 return FAILED;
1423         }
1424         return FAILED;
1425
1426       maybe_retry:
1427
1428         /* we requeue for retry because the error was retryable, and
1429          * the request was not marked fast fail.  Note that above,
1430          * even if the request is marked fast fail, we still requeue
1431          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1432         if ((++scmd->retries) <= scmd->allowed
1433             && !scsi_noretry_cmd(scmd)) {
1434                 return NEEDS_RETRY;
1435         } else {
1436                 /*
1437                  * no more retries - report this one back to upper level.
1438                  */
1439                 return SUCCESS;
1440         }
1441 }
1442
1443 /**
1444  * scsi_eh_lock_door - Prevent medium removal for the specified device
1445  * @sdev:       SCSI device to prevent medium removal
1446  *
1447  * Locking:
1448  *      We must be called from process context; scsi_allocate_request()
1449  *      may sleep.
1450  *
1451  * Notes:
1452  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1453  *      head of the devices request queue, and continue.
1454  *
1455  * Bugs:
1456  *      scsi_allocate_request() may sleep waiting for existing requests to
1457  *      be processed.  However, since we haven't kicked off any request
1458  *      processing for this host, this may deadlock.
1459  *
1460  *      If scsi_allocate_request() fails for what ever reason, we
1461  *      completely forget to lock the door.
1462  */
1463 static void scsi_eh_lock_door(struct scsi_device *sdev)
1464 {
1465         unsigned char cmnd[MAX_COMMAND_SIZE];
1466
1467         cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1468         cmnd[1] = 0;
1469         cmnd[2] = 0;
1470         cmnd[3] = 0;
1471         cmnd[4] = SCSI_REMOVAL_PREVENT;
1472         cmnd[5] = 0;
1473
1474         scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
1475                            5, NULL, NULL, GFP_KERNEL);
1476 }
1477
1478
1479 /**
1480  * scsi_restart_operations - restart io operations to the specified host.
1481  * @shost:      Host we are restarting.
1482  *
1483  * Notes:
1484  *    When we entered the error handler, we blocked all further i/o to
1485  *    this device.  we need to 'reverse' this process.
1486  */
1487 static void scsi_restart_operations(struct Scsi_Host *shost)
1488 {
1489         struct scsi_device *sdev;
1490         unsigned long flags;
1491
1492         /*
1493          * If the door was locked, we need to insert a door lock request
1494          * onto the head of the SCSI request queue for the device.  There
1495          * is no point trying to lock the door of an off-line device.
1496          */
1497         shost_for_each_device(sdev, shost) {
1498                 if (scsi_device_online(sdev) && sdev->locked)
1499                         scsi_eh_lock_door(sdev);
1500         }
1501
1502         /*
1503          * next free up anything directly waiting upon the host.  this
1504          * will be requests for character device operations, and also for
1505          * ioctls to queued block devices.
1506          */
1507         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1508                                           __func__));
1509
1510         spin_lock_irqsave(shost->host_lock, flags);
1511         if (scsi_host_set_state(shost, SHOST_RUNNING))
1512                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1513                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1514         spin_unlock_irqrestore(shost->host_lock, flags);
1515
1516         wake_up(&shost->host_wait);
1517
1518         /*
1519          * finally we need to re-initiate requests that may be pending.  we will
1520          * have had everything blocked while error handling is taking place, and
1521          * now that error recovery is done, we will need to ensure that these
1522          * requests are started.
1523          */
1524         scsi_run_host_queues(shost);
1525 }
1526
1527 /**
1528  * scsi_eh_ready_devs - check device ready state and recover if not.
1529  * @shost:      host to be recovered.
1530  * @work_q:     &list_head for pending commands.
1531  * @done_q:     &list_head for processed commands.
1532  */
1533 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1534                         struct list_head *work_q,
1535                         struct list_head *done_q)
1536 {
1537         if (!scsi_eh_stu(shost, work_q, done_q))
1538                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1539                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1540                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1541                                         if (!scsi_eh_host_reset(work_q, done_q))
1542                                                 scsi_eh_offline_sdevs(work_q,
1543                                                                       done_q);
1544 }
1545 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1546
1547 /**
1548  * scsi_eh_flush_done_q - finish processed commands or retry them.
1549  * @done_q:     list_head of processed commands.
1550  */
1551 void scsi_eh_flush_done_q(struct list_head *done_q)
1552 {
1553         struct scsi_cmnd *scmd, *next;
1554
1555         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1556                 list_del_init(&scmd->eh_entry);
1557                 if (scsi_device_online(scmd->device) &&
1558                     !scsi_noretry_cmd(scmd) &&
1559                     (++scmd->retries <= scmd->allowed)) {
1560                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1561                                                           " retry cmd: %p\n",
1562                                                           current->comm,
1563                                                           scmd));
1564                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1565                 } else {
1566                         /*
1567                          * If just we got sense for the device (called
1568                          * scsi_eh_get_sense), scmd->result is already
1569                          * set, do not set DRIVER_TIMEOUT.
1570                          */
1571                         if (!scmd->result)
1572                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1573                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1574                                                         " cmd: %p\n",
1575                                                         current->comm, scmd));
1576                         scsi_finish_command(scmd);
1577                 }
1578         }
1579 }
1580 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1581
1582 /**
1583  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1584  * @shost:      Host to unjam.
1585  *
1586  * Notes:
1587  *    When we come in here, we *know* that all commands on the bus have
1588  *    either completed, failed or timed out.  we also know that no further
1589  *    commands are being sent to the host, so things are relatively quiet
1590  *    and we have freedom to fiddle with things as we wish.
1591  *
1592  *    This is only the *default* implementation.  it is possible for
1593  *    individual drivers to supply their own version of this function, and
1594  *    if the maintainer wishes to do this, it is strongly suggested that
1595  *    this function be taken as a template and modified.  this function
1596  *    was designed to correctly handle problems for about 95% of the
1597  *    different cases out there, and it should always provide at least a
1598  *    reasonable amount of error recovery.
1599  *
1600  *    Any command marked 'failed' or 'timeout' must eventually have
1601  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1602  *    here, so when we restart the host after we return it should have an
1603  *    empty queue.
1604  */
1605 static void scsi_unjam_host(struct Scsi_Host *shost)
1606 {
1607         unsigned long flags;
1608         LIST_HEAD(eh_work_q);
1609         LIST_HEAD(eh_done_q);
1610
1611         spin_lock_irqsave(shost->host_lock, flags);
1612         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1613         spin_unlock_irqrestore(shost->host_lock, flags);
1614
1615         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1616
1617         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1618                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1619                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1620
1621         scsi_eh_flush_done_q(&eh_done_q);
1622 }
1623
1624 /**
1625  * scsi_error_handler - SCSI error handler thread
1626  * @data:       Host for which we are running.
1627  *
1628  * Notes:
1629  *    This is the main error handling loop.  This is run as a kernel thread
1630  *    for every SCSI host and handles all error handling activity.
1631  */
1632 int scsi_error_handler(void *data)
1633 {
1634         struct Scsi_Host *shost = data;
1635
1636         /*
1637          * We use TASK_INTERRUPTIBLE so that the thread is not
1638          * counted against the load average as a running process.
1639          * We never actually get interrupted because kthread_run
1640          * disables singal delivery for the created thread.
1641          */
1642         set_current_state(TASK_INTERRUPTIBLE);
1643         while (!kthread_should_stop()) {
1644                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1645                     shost->host_failed != shost->host_busy) {
1646                         SCSI_LOG_ERROR_RECOVERY(1,
1647                                 printk("Error handler scsi_eh_%d sleeping\n",
1648                                         shost->host_no));
1649                         schedule();
1650                         set_current_state(TASK_INTERRUPTIBLE);
1651                         continue;
1652                 }
1653
1654                 __set_current_state(TASK_RUNNING);
1655                 SCSI_LOG_ERROR_RECOVERY(1,
1656                         printk("Error handler scsi_eh_%d waking up\n",
1657                                 shost->host_no));
1658
1659                 /*
1660                  * We have a host that is failing for some reason.  Figure out
1661                  * what we need to do to get it up and online again (if we can).
1662                  * If we fail, we end up taking the thing offline.
1663                  */
1664                 if (shost->transportt->eh_strategy_handler)
1665                         shost->transportt->eh_strategy_handler(shost);
1666                 else
1667                         scsi_unjam_host(shost);
1668
1669                 /*
1670                  * Note - if the above fails completely, the action is to take
1671                  * individual devices offline and flush the queue of any
1672                  * outstanding requests that may have been pending.  When we
1673                  * restart, we restart any I/O to any other devices on the bus
1674                  * which are still online.
1675                  */
1676                 scsi_restart_operations(shost);
1677                 set_current_state(TASK_INTERRUPTIBLE);
1678         }
1679         __set_current_state(TASK_RUNNING);
1680
1681         SCSI_LOG_ERROR_RECOVERY(1,
1682                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1683         shost->ehandler = NULL;
1684         return 0;
1685 }
1686
1687 /*
1688  * Function:    scsi_report_bus_reset()
1689  *
1690  * Purpose:     Utility function used by low-level drivers to report that
1691  *              they have observed a bus reset on the bus being handled.
1692  *
1693  * Arguments:   shost       - Host in question
1694  *              channel     - channel on which reset was observed.
1695  *
1696  * Returns:     Nothing
1697  *
1698  * Lock status: Host lock must be held.
1699  *
1700  * Notes:       This only needs to be called if the reset is one which
1701  *              originates from an unknown location.  Resets originated
1702  *              by the mid-level itself don't need to call this, but there
1703  *              should be no harm.
1704  *
1705  *              The main purpose of this is to make sure that a CHECK_CONDITION
1706  *              is properly treated.
1707  */
1708 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1709 {
1710         struct scsi_device *sdev;
1711
1712         __shost_for_each_device(sdev, shost) {
1713                 if (channel == sdev_channel(sdev))
1714                         __scsi_report_device_reset(sdev, NULL);
1715         }
1716 }
1717 EXPORT_SYMBOL(scsi_report_bus_reset);
1718
1719 /*
1720  * Function:    scsi_report_device_reset()
1721  *
1722  * Purpose:     Utility function used by low-level drivers to report that
1723  *              they have observed a device reset on the device being handled.
1724  *
1725  * Arguments:   shost       - Host in question
1726  *              channel     - channel on which reset was observed
1727  *              target      - target on which reset was observed
1728  *
1729  * Returns:     Nothing
1730  *
1731  * Lock status: Host lock must be held
1732  *
1733  * Notes:       This only needs to be called if the reset is one which
1734  *              originates from an unknown location.  Resets originated
1735  *              by the mid-level itself don't need to call this, but there
1736  *              should be no harm.
1737  *
1738  *              The main purpose of this is to make sure that a CHECK_CONDITION
1739  *              is properly treated.
1740  */
1741 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1742 {
1743         struct scsi_device *sdev;
1744
1745         __shost_for_each_device(sdev, shost) {
1746                 if (channel == sdev_channel(sdev) &&
1747                     target == sdev_id(sdev))
1748                         __scsi_report_device_reset(sdev, NULL);
1749         }
1750 }
1751 EXPORT_SYMBOL(scsi_report_device_reset);
1752
1753 static void
1754 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1755 {
1756 }
1757
1758 /*
1759  * Function:    scsi_reset_provider
1760  *
1761  * Purpose:     Send requested reset to a bus or device at any phase.
1762  *
1763  * Arguments:   device  - device to send reset to
1764  *              flag - reset type (see scsi.h)
1765  *
1766  * Returns:     SUCCESS/FAILURE.
1767  *
1768  * Notes:       This is used by the SCSI Generic driver to provide
1769  *              Bus/Device reset capability.
1770  */
1771 int
1772 scsi_reset_provider(struct scsi_device *dev, int flag)
1773 {
1774         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1775         struct Scsi_Host *shost = dev->host;
1776         struct request req;
1777         unsigned long flags;
1778         int rtn;
1779
1780         blk_rq_init(NULL, &req);
1781         scmd->request = &req;
1782
1783         scmd->cmnd = req.cmd;
1784
1785         scmd->scsi_done         = scsi_reset_provider_done_command;
1786         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1787
1788         scmd->cmd_len                   = 0;
1789
1790         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1791
1792         spin_lock_irqsave(shost->host_lock, flags);
1793         shost->tmf_in_progress = 1;
1794         spin_unlock_irqrestore(shost->host_lock, flags);
1795
1796         switch (flag) {
1797         case SCSI_TRY_RESET_DEVICE:
1798                 rtn = scsi_try_bus_device_reset(scmd);
1799                 if (rtn == SUCCESS)
1800                         break;
1801                 /* FALLTHROUGH */
1802         case SCSI_TRY_RESET_TARGET:
1803                 rtn = scsi_try_target_reset(scmd);
1804                 if (rtn == SUCCESS)
1805                         break;
1806                 /* FALLTHROUGH */
1807         case SCSI_TRY_RESET_BUS:
1808                 rtn = scsi_try_bus_reset(scmd);
1809                 if (rtn == SUCCESS)
1810                         break;
1811                 /* FALLTHROUGH */
1812         case SCSI_TRY_RESET_HOST:
1813                 rtn = scsi_try_host_reset(scmd);
1814                 break;
1815         default:
1816                 rtn = FAILED;
1817         }
1818
1819         spin_lock_irqsave(shost->host_lock, flags);
1820         shost->tmf_in_progress = 0;
1821         spin_unlock_irqrestore(shost->host_lock, flags);
1822
1823         /*
1824          * be sure to wake up anyone who was sleeping or had their queue
1825          * suspended while we performed the TMF.
1826          */
1827         SCSI_LOG_ERROR_RECOVERY(3,
1828                 printk("%s: waking up host to restart after TMF\n",
1829                 __func__));
1830
1831         wake_up(&shost->host_wait);
1832
1833         scsi_run_host_queues(shost);
1834
1835         scsi_next_command(scmd);
1836         return rtn;
1837 }
1838 EXPORT_SYMBOL(scsi_reset_provider);
1839
1840 /**
1841  * scsi_normalize_sense - normalize main elements from either fixed or
1842  *                      descriptor sense data format into a common format.
1843  *
1844  * @sense_buffer:       byte array containing sense data returned by device
1845  * @sb_len:             number of valid bytes in sense_buffer
1846  * @sshdr:              pointer to instance of structure that common
1847  *                      elements are written to.
1848  *
1849  * Notes:
1850  *      The "main elements" from sense data are: response_code, sense_key,
1851  *      asc, ascq and additional_length (only for descriptor format).
1852  *
1853  *      Typically this function can be called after a device has
1854  *      responded to a SCSI command with the CHECK_CONDITION status.
1855  *
1856  * Return value:
1857  *      1 if valid sense data information found, else 0;
1858  */
1859 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1860                          struct scsi_sense_hdr *sshdr)
1861 {
1862         if (!sense_buffer || !sb_len)
1863                 return 0;
1864
1865         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1866
1867         sshdr->response_code = (sense_buffer[0] & 0x7f);
1868
1869         if (!scsi_sense_valid(sshdr))
1870                 return 0;
1871
1872         if (sshdr->response_code >= 0x72) {
1873                 /*
1874                  * descriptor format
1875                  */
1876                 if (sb_len > 1)
1877                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1878                 if (sb_len > 2)
1879                         sshdr->asc = sense_buffer[2];
1880                 if (sb_len > 3)
1881                         sshdr->ascq = sense_buffer[3];
1882                 if (sb_len > 7)
1883                         sshdr->additional_length = sense_buffer[7];
1884         } else {
1885                 /*
1886                  * fixed format
1887                  */
1888                 if (sb_len > 2)
1889                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1890                 if (sb_len > 7) {
1891                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1892                                          sb_len : (sense_buffer[7] + 8);
1893                         if (sb_len > 12)
1894                                 sshdr->asc = sense_buffer[12];
1895                         if (sb_len > 13)
1896                                 sshdr->ascq = sense_buffer[13];
1897                 }
1898         }
1899
1900         return 1;
1901 }
1902 EXPORT_SYMBOL(scsi_normalize_sense);
1903
1904 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1905                                  struct scsi_sense_hdr *sshdr)
1906 {
1907         return scsi_normalize_sense(cmd->sense_buffer,
1908                         SCSI_SENSE_BUFFERSIZE, sshdr);
1909 }
1910 EXPORT_SYMBOL(scsi_command_normalize_sense);
1911
1912 /**
1913  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1914  * @sense_buffer:       byte array of descriptor format sense data
1915  * @sb_len:             number of valid bytes in sense_buffer
1916  * @desc_type:          value of descriptor type to find
1917  *                      (e.g. 0 -> information)
1918  *
1919  * Notes:
1920  *      only valid when sense data is in descriptor format
1921  *
1922  * Return value:
1923  *      pointer to start of (first) descriptor if found else NULL
1924  */
1925 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1926                                 int desc_type)
1927 {
1928         int add_sen_len, add_len, desc_len, k;
1929         const u8 * descp;
1930
1931         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1932                 return NULL;
1933         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1934                 return NULL;
1935         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1936                         add_sen_len : (sb_len - 8);
1937         descp = &sense_buffer[8];
1938         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1939                 descp += desc_len;
1940                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1941                 desc_len = add_len + 2;
1942                 if (descp[0] == desc_type)
1943                         return descp;
1944                 if (add_len < 0) // short descriptor ??
1945                         break;
1946         }
1947         return NULL;
1948 }
1949 EXPORT_SYMBOL(scsi_sense_desc_find);
1950
1951 /**
1952  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
1953  * @sense_buffer:       byte array of sense data
1954  * @sb_len:             number of valid bytes in sense_buffer
1955  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1956  *                      field will be placed if found.
1957  *
1958  * Return value:
1959  *      1 if information field found, 0 if not found.
1960  */
1961 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1962                             u64 * info_out)
1963 {
1964         int j;
1965         const u8 * ucp;
1966         u64 ull;
1967
1968         if (sb_len < 7)
1969                 return 0;
1970         switch (sense_buffer[0] & 0x7f) {
1971         case 0x70:
1972         case 0x71:
1973                 if (sense_buffer[0] & 0x80) {
1974                         *info_out = (sense_buffer[3] << 24) +
1975                                     (sense_buffer[4] << 16) +
1976                                     (sense_buffer[5] << 8) + sense_buffer[6];
1977                         return 1;
1978                 } else
1979                         return 0;
1980         case 0x72:
1981         case 0x73:
1982                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1983                                            0 /* info desc */);
1984                 if (ucp && (0xa == ucp[1])) {
1985                         ull = 0;
1986                         for (j = 0; j < 8; ++j) {
1987                                 if (j > 0)
1988                                         ull <<= 8;
1989                                 ull |= ucp[4 + j];
1990                         }
1991                         *info_out = ull;
1992                         return 1;
1993                 } else
1994                         return 0;
1995         default:
1996                 return 0;
1997         }
1998 }
1999 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2000
2001 /**
2002  * scsi_build_sense_buffer - build sense data in a buffer
2003  * @desc:       Sense format (non zero == descriptor format,
2004  *              0 == fixed format)
2005  * @buf:        Where to build sense data
2006  * @key:        Sense key
2007  * @asc:        Additional sense code
2008  * @ascq:       Additional sense code qualifier
2009  *
2010  **/
2011 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2012 {
2013         if (desc) {
2014                 buf[0] = 0x72;  /* descriptor, current */
2015                 buf[1] = key;
2016                 buf[2] = asc;
2017                 buf[3] = ascq;
2018                 buf[7] = 0;
2019         } else {
2020                 buf[0] = 0x70;  /* fixed, current */
2021                 buf[2] = key;
2022                 buf[7] = 0xa;
2023                 buf[12] = asc;
2024                 buf[13] = ascq;
2025         }
2026 }
2027 EXPORT_SYMBOL(scsi_build_sense_buffer);