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