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/interrupt.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/delay.h>
  26
  27 #include <scsi/scsi.h>
  28 #include <scsi/scsi_dbg.h>
  29 #include <scsi/scsi_device.h>
  30 #include <scsi/scsi_eh.h>
  31 #include <scsi/scsi_host.h>
  32 #include <scsi/scsi_ioctl.h>
  33 #include <scsi/scsi_request.h>
  34
  35 #include "scsi_priv.h"
  36 #include "scsi_logging.h"
  37
  38 #define SENSE_TIMEOUT           (10*HZ)
  39 #define START_UNIT_TIMEOUT      (30*HZ)
  40
  41 /*
  42  * These should *probably* be handled by the host itself.
  43  * Since it is allowed to sleep, it probably should.
  44  */
  45 #define BUS_RESET_SETTLE_TIME   (10)
  46 #define HOST_RESET_SETTLE_TIME  (10)
  47
  48 /* called with shost->host_lock held */
  49 void scsi_eh_wakeup(struct Scsi_Host *shost)
  50 {
  51         if (shost->host_busy == shost->host_failed) {
  52                 up(shost->eh_wait);
  53                 SCSI_LOG_ERROR_RECOVERY(5,
  54                                 printk("Waking error handler thread\n"));
  55         }
  56 }
  57
  58 /**
  59  * scsi_eh_scmd_add - add scsi cmd to error handling.
  60  * @scmd:       scmd to run eh on.
  61  * @eh_flag:    optional SCSI_EH flag.
  62  *
  63  * Return value:
  64  *      0 on failure.
  65  **/
  66 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  67 {
  68         struct Scsi_Host *shost = scmd->device->host;
  69         unsigned long flags;
  70
  71         if (shost->eh_wait == NULL)
  72                 return 0;
  73
  74         spin_lock_irqsave(shost->host_lock, flags);
  75
  76         scsi_eh_eflags_set(scmd, eh_flag);
  77         /*
  78          * FIXME: Can we stop setting owner and state.
  79          */
  80         scmd->owner = SCSI_OWNER_ERROR_HANDLER;
  81         scmd->state = SCSI_STATE_FAILED;
  82         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
  83         set_bit(SHOST_RECOVERY, &shost->shost_state);
  84         shost->host_failed++;
  85         scsi_eh_wakeup(shost);
  86         spin_unlock_irqrestore(shost->host_lock, flags);
  87         return 1;
  88 }
  89
  90 /**
  91  * scsi_add_timer - Start timeout timer for a single scsi command.
  92  * @scmd:       scsi command that is about to start running.
  93  * @timeout:    amount of time to allow this command to run.
  94  * @complete:   timeout function to call if timer isn't canceled.
  95  *
  96  * Notes:
  97  *    This should be turned into an inline function.  Each scsi command
  98  *    has its own timer, and as it is added to the queue, we set up the
  99  *    timer.  When the command completes, we cancel the timer.
 100  **/
 101 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
 102                     void (*complete)(struct scsi_cmnd *))
 103 {
 104
 105         /*
 106          * If the clock was already running for this command, then
 107          * first delete the timer.  The timer handling code gets rather
 108          * confused if we don't do this.
 109          */
 110         if (scmd->eh_timeout.function)
 111                 del_timer(&scmd->eh_timeout);
 112
 113         scmd->eh_timeout.data = (unsigned long)scmd;
 114         scmd->eh_timeout.expires = jiffies + timeout;
 115         scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
 116
 117         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
 118                                           " %d, (%p)\n", __FUNCTION__,
 119                                           scmd, timeout, complete));
 120
 121         add_timer(&scmd->eh_timeout);
 122 }
 123 EXPORT_SYMBOL(scsi_add_timer);
 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 EXPORT_SYMBOL(scsi_delete_timer);
 152
 153 /**
 154  * scsi_times_out - Timeout function for normal scsi commands.
 155  * @scmd:       Cmd that is timing out.
 156  *
 157  * Notes:
 158  *     We do not need to lock this.  There is the potential for a race
 159  *     only in that the normal completion handling might run, but if the
 160  *     normal completion function determines that the timer has already
 161  *     fired, then it mustn't do anything.
 162  **/
 163 void scsi_times_out(struct scsi_cmnd *scmd)
 164 {
 165         scsi_log_completion(scmd, TIMEOUT_ERROR);
 166
 167         if (scmd->device->host->hostt->eh_timed_out)
 168                 switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
 169                 case EH_HANDLED:
 170                         __scsi_done(scmd);
 171                         return;
 172                 case EH_RESET_TIMER:
 173                         /* This allows a single retry even of a command
 174                          * with allowed == 0 */
 175                         if (scmd->retries++ > scmd->allowed)
 176                                 break;
 177                         scsi_add_timer(scmd, scmd->timeout_per_command,
 178                                        scsi_times_out);
 179                         return;
 180                 case EH_NOT_HANDLED:
 181                         break;
 182                 }
 183
 184         if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 185                 panic("Error handler thread not present at %p %p %s %d",
 186                       scmd, scmd->device->host, __FILE__, __LINE__);
 187         }
 188 }
 189
 190 /**
 191  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 192  * @sdev:       Device on which we are performing recovery.
 193  *
 194  * Description:
 195  *     We block until the host is out of error recovery, and then check to
 196  *     see whether the host or the device is offline.
 197  *
 198  * Return value:
 199  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 200  **/
 201 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 202 {
 203         int online;
 204
 205         wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state)));
 206
 207         online = scsi_device_online(sdev);
 208
 209         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
 210                                           online));
 211
 212         return online;
 213 }
 214 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 215
 216 #ifdef CONFIG_SCSI_LOGGING
 217 /**
 218  * scsi_eh_prt_fail_stats - Log info on failures.
 219  * @shost:      scsi host being recovered.
 220  * @work_q:     Queue of scsi cmds to process.
 221  **/
 222 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 223                                           struct list_head *work_q)
 224 {
 225         struct scsi_cmnd *scmd;
 226         struct scsi_device *sdev;
 227         int total_failures = 0;
 228         int cmd_failed = 0;
 229         int cmd_cancel = 0;
 230         int devices_failed = 0;
 231
 232         shost_for_each_device(sdev, shost) {
 233                 list_for_each_entry(scmd, work_q, eh_entry) {
 234                         if (scmd->device == sdev) {
 235                                 ++total_failures;
 236                                 if (scsi_eh_eflags_chk(scmd,
 237                                                        SCSI_EH_CANCEL_CMD))
 238                                         ++cmd_cancel;
 239                                 else
 240                                         ++cmd_failed;
 241                         }
 242                 }
 243
 244                 if (cmd_cancel || cmd_failed) {
 245                         SCSI_LOG_ERROR_RECOVERY(3,
 246                                 printk("%s: %d:%d:%d:%d cmds failed: %d,"
 247                                        " cancel: %d\n",
 248                                        __FUNCTION__, shost->host_no,
 249                                        sdev->channel, sdev->id, sdev->lun,
 250                                        cmd_failed, cmd_cancel));
 251                         cmd_cancel = 0;
 252                         cmd_failed = 0;
 253                         ++devices_failed;
 254                 }
 255         }
 256
 257         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 258                                           " devices require eh work\n",
 259                                   total_failures, devices_failed));
 260 }
 261 #endif
 262
 263 /**
 264  * scsi_check_sense - Examine scsi cmd sense
 265  * @scmd:       Cmd to have sense checked.
 266  *
 267  * Return value:
 268  *      SUCCESS or FAILED or NEEDS_RETRY
 269  *
 270  * Notes:
 271  *      When a deferred error is detected the current command has
 272  *      not been executed and needs retrying.
 273  **/
 274 static int scsi_check_sense(struct scsi_cmnd *scmd)
 275 {
 276         struct scsi_sense_hdr sshdr;
 277
 278         if (! scsi_command_normalize_sense(scmd, &sshdr))
 279                 return FAILED;  /* no valid sense data */
 280
 281         if (scsi_sense_is_deferred(&sshdr))
 282                 return NEEDS_RETRY;
 283
 284         /*
 285          * Previous logic looked for FILEMARK, EOM or ILI which are
 286          * mainly associated with tapes and returned SUCCESS.
 287          */
 288         if (sshdr.response_code == 0x70) {
 289                 /* fixed format */
 290                 if (scmd->sense_buffer[2] & 0xe0)
 291                         return SUCCESS;
 292         } else {
 293                 /*
 294                  * descriptor format: look for "stream commands sense data
 295                  * descriptor" (see SSC-3). Assume single sense data
 296                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 297                  */
 298                 if ((sshdr.additional_length > 3) &&
 299                     (scmd->sense_buffer[8] == 0x4) &&
 300                     (scmd->sense_buffer[11] & 0xe0))
 301                         return SUCCESS;
 302         }
 303
 304         switch (sshdr.sense_key) {
 305         case NO_SENSE:
 306                 return SUCCESS;
 307         case RECOVERED_ERROR:
 308                 return /* soft_error */ SUCCESS;
 309
 310         case ABORTED_COMMAND:
 311                 return NEEDS_RETRY;
 312         case NOT_READY:
 313         case UNIT_ATTENTION:
 314                 /*
 315                  * if we are expecting a cc/ua because of a bus reset that we
 316                  * performed, treat this just as a retry.  otherwise this is
 317                  * information that we should pass up to the upper-level driver
 318                  * so that we can deal with it there.
 319                  */
 320                 if (scmd->device->expecting_cc_ua) {
 321                         scmd->device->expecting_cc_ua = 0;
 322                         return NEEDS_RETRY;
 323                 }
 324                 /*
 325                  * if the device is in the process of becoming ready, we
 326                  * should retry.
 327                  */
 328                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 329                         return NEEDS_RETRY;
 330                 /*
 331                  * if the device is not started, we need to wake
 332                  * the error handler to start the motor
 333                  */
 334                 if (scmd->device->allow_restart &&
 335                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 336                         return FAILED;
 337                 return SUCCESS;
 338
 339                 /* these three are not supported */
 340         case COPY_ABORTED:
 341         case VOLUME_OVERFLOW:
 342         case MISCOMPARE:
 343                 return SUCCESS;
 344
 345         case MEDIUM_ERROR:
 346                 return NEEDS_RETRY;
 347
 348         case HARDWARE_ERROR:
 349                 if (scmd->device->retry_hwerror)
 350                         return NEEDS_RETRY;
 351                 else
 352                         return SUCCESS;
 353
 354         case ILLEGAL_REQUEST:
 355         case BLANK_CHECK:
 356         case DATA_PROTECT:
 357         default:
 358                 return SUCCESS;
 359         }
 360 }
 361
 362 /**
 363  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 364  * @scmd:       SCSI cmd to examine.
 365  *
 366  * Notes:
 367  *    This is *only* called when we are examining the status of commands
 368  *    queued during error recovery.  the main difference here is that we
 369  *    don't allow for the possibility of retries here, and we are a lot
 370  *    more restrictive about what we consider acceptable.
 371  **/
 372 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 373 {
 374         /*
 375          * first check the host byte, to see if there is anything in there
 376          * that would indicate what we need to do.
 377          */
 378         if (host_byte(scmd->result) == DID_RESET) {
 379                 /*
 380                  * rats.  we are already in the error handler, so we now
 381                  * get to try and figure out what to do next.  if the sense
 382                  * is valid, we have a pretty good idea of what to do.
 383                  * if not, we mark it as FAILED.
 384                  */
 385                 return scsi_check_sense(scmd);
 386         }
 387         if (host_byte(scmd->result) != DID_OK)
 388                 return FAILED;
 389
 390         /*
 391          * next, check the message byte.
 392          */
 393         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 394                 return FAILED;
 395
 396         /*
 397          * now, check the status byte to see if this indicates
 398          * anything special.
 399          */
 400         switch (status_byte(scmd->result)) {
 401         case GOOD:
 402         case COMMAND_TERMINATED:
 403                 return SUCCESS;
 404         case CHECK_CONDITION:
 405                 return scsi_check_sense(scmd);
 406         case CONDITION_GOOD:
 407         case INTERMEDIATE_GOOD:
 408         case INTERMEDIATE_C_GOOD:
 409                 /*
 410                  * who knows?  FIXME(eric)
 411                  */
 412                 return SUCCESS;
 413         case BUSY:
 414         case QUEUE_FULL:
 415         case RESERVATION_CONFLICT:
 416         default:
 417                 return FAILED;
 418         }
 419         return FAILED;
 420 }
 421
 422 /**
 423  * scsi_eh_times_out - timeout function for error handling.
 424  * @scmd:       Cmd that is timing out.
 425  *
 426  * Notes:
 427  *    During error handling, the kernel thread will be sleeping waiting
 428  *    for some action to complete on the device.  our only job is to
 429  *    record that it timed out, and to wake up the thread.
 430  **/
 431 static void scsi_eh_times_out(struct scsi_cmnd *scmd)
 432 {
 433         scsi_eh_eflags_set(scmd, SCSI_EH_REC_TIMEOUT);
 434         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
 435                                           scmd));
 436
 437         if (scmd->device->host->eh_action)
 438                 up(scmd->device->host->eh_action);
 439 }
 440
 441 /**
 442  * scsi_eh_done - Completion function for error handling.
 443  * @scmd:       Cmd that is done.
 444  **/
 445 static void scsi_eh_done(struct scsi_cmnd *scmd)
 446 {
 447         /*
 448          * if the timeout handler is already running, then just set the
 449          * flag which says we finished late, and return.  we have no
 450          * way of stopping the timeout handler from running, so we must
 451          * always defer to it.
 452          */
 453         if (del_timer(&scmd->eh_timeout)) {
 454                 scmd->request->rq_status = RQ_SCSI_DONE;
 455                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
 456
 457                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
 458                                            __FUNCTION__, scmd, scmd->result));
 459
 460                 if (scmd->device->host->eh_action)
 461                         up(scmd->device->host->eh_action);
 462         }
 463 }
 464
 465 /**
 466  * scsi_send_eh_cmnd  - send a cmd to a device as part of error recovery.
 467  * @scmd:       SCSI Cmd to send.
 468  * @timeout:    Timeout for cmd.
 469  *
 470  * Notes:
 471  *    The initialization of the structures is quite a bit different in
 472  *    this case, and furthermore, there is a different completion handler
 473  *    vs scsi_dispatch_cmd.
 474  * Return value:
 475  *    SUCCESS or FAILED or NEEDS_RETRY
 476  **/
 477 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
 478 {
 479         struct scsi_device *sdev = scmd->device;
 480         struct Scsi_Host *shost = sdev->host;
 481         DECLARE_MUTEX_LOCKED(sem);
 482         unsigned long flags;
 483         int rtn = SUCCESS;
 484
 485         /*
 486          * we will use a queued command if possible, otherwise we will
 487          * emulate the queuing and calling of completion function ourselves.
 488          */
 489         scmd->owner = SCSI_OWNER_LOWLEVEL;
 490
 491         if (sdev->scsi_level <= SCSI_2)
 492                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 493                         (sdev->lun << 5 & 0xe0);
 494
 495         scsi_add_timer(scmd, timeout, scsi_eh_times_out);
 496
 497         /*
 498          * set up the semaphore so we wait for the command to complete.
 499          */
 500         shost->eh_action = &sem;
 501         scmd->request->rq_status = RQ_SCSI_BUSY;
 502
 503         spin_lock_irqsave(shost->host_lock, flags);
 504         scsi_log_send(scmd);
 505         shost->hostt->queuecommand(scmd, scsi_eh_done);
 506         spin_unlock_irqrestore(shost->host_lock, flags);
 507
 508         down(&sem);
 509         scsi_log_completion(scmd, SUCCESS);
 510
 511         shost->eh_action = NULL;
 512
 513         /*
 514          * see if timeout.  if so, tell the host to forget about it.
 515          * in other words, we don't want a callback any more.
 516          */
 517         if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
 518                 scsi_eh_eflags_clr(scmd,  SCSI_EH_REC_TIMEOUT);
 519                 scmd->owner = SCSI_OWNER_LOWLEVEL;
 520
 521                 /*
 522                  * as far as the low level driver is
 523                  * concerned, this command is still active, so
 524                  * we must give the low level driver a chance
 525                  * to abort it. (db)
 526                  *
 527                  * FIXME(eric) - we are not tracking whether we could
 528                  * abort a timed out command or not.  not sure how
 529                  * we should treat them differently anyways.
 530                  */
 531                 spin_lock_irqsave(shost->host_lock, flags);
 532                 if (shost->hostt->eh_abort_handler)
 533                         shost->hostt->eh_abort_handler(scmd);
 534                 spin_unlock_irqrestore(shost->host_lock, flags);
 535
 536                 scmd->request->rq_status = RQ_SCSI_DONE;
 537                 scmd->owner = SCSI_OWNER_ERROR_HANDLER;
 538
 539                 rtn = FAILED;
 540         }
 541
 542         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
 543                                           __FUNCTION__, scmd, rtn));
 544
 545         /*
 546          * now examine the actual status codes to see whether the command
 547          * actually did complete normally.
 548          */
 549         if (rtn == SUCCESS) {
 550                 rtn = scsi_eh_completed_normally(scmd);
 551                 SCSI_LOG_ERROR_RECOVERY(3,
 552                         printk("%s: scsi_eh_completed_normally %x\n",
 553                                __FUNCTION__, rtn));
 554                 switch (rtn) {
 555                 case SUCCESS:
 556                 case NEEDS_RETRY:
 557                 case FAILED:
 558                         break;
 559                 default:
 560                         rtn = FAILED;
 561                         break;
 562                 }
 563         }
 564
 565         return rtn;
 566 }
 567
 568 /**
 569  * scsi_request_sense - Request sense data from a particular target.
 570  * @scmd:       SCSI cmd for request sense.
 571  *
 572  * Notes:
 573  *    Some hosts automatically obtain this information, others require
 574  *    that we obtain it on our own. This function will *not* return until
 575  *    the command either times out, or it completes.
 576  **/
 577 static int scsi_request_sense(struct scsi_cmnd *scmd)
 578 {
 579         static unsigned char generic_sense[6] =
 580         {REQUEST_SENSE, 0, 0, 0, 252, 0};
 581         unsigned char *scsi_result;
 582         int saved_result;
 583         int rtn;
 584
 585         memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
 586
 587         scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
 588
 589
 590         if (unlikely(!scsi_result)) {
 591                 printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
 592                        __FUNCTION__);
 593                 return FAILED;
 594         }
 595
 596         /*
 597          * zero the sense buffer.  some host adapters automatically always
 598          * request sense, so it is not a good idea that
 599          * scmd->request_buffer and scmd->sense_buffer point to the same
 600          * address (db).  0 is not a valid sense code.
 601          */
 602         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 603         memset(scsi_result, 0, 252);
 604
 605         saved_result = scmd->result;
 606         scmd->request_buffer = scsi_result;
 607         scmd->request_bufflen = 252;
 608         scmd->use_sg = 0;
 609         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 610         scmd->sc_data_direction = DMA_FROM_DEVICE;
 611         scmd->underflow = 0;
 612
 613         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 614
 615         /* last chance to have valid sense data */
 616         if(!SCSI_SENSE_VALID(scmd)) {
 617                 memcpy(scmd->sense_buffer, scmd->request_buffer,
 618                        sizeof(scmd->sense_buffer));
 619         }
 620
 621         kfree(scsi_result);
 622
 623         /*
 624          * when we eventually call scsi_finish, we really wish to complete
 625          * the original request, so let's restore the original data. (db)
 626          */
 627         scsi_setup_cmd_retry(scmd);
 628         scmd->result = saved_result;
 629         return rtn;
 630 }
 631
 632 /**
 633  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 634  * @scmd:       Original SCSI cmd that eh has finished.
 635  * @done_q:     Queue for processed commands.
 636  *
 637  * Notes:
 638  *    We don't want to use the normal command completion while we are are
 639  *    still handling errors - it may cause other commands to be queued,
 640  *    and that would disturb what we are doing.  thus we really want to
 641  *    keep a list of pending commands for final completion, and once we
 642  *    are ready to leave error handling we handle completion for real.
 643  **/
 644 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
 645                                struct list_head *done_q)
 646 {
 647         scmd->device->host->host_failed--;
 648         scmd->state = SCSI_STATE_BHQUEUE;
 649
 650         scsi_eh_eflags_clr_all(scmd);
 651
 652         /*
 653          * set this back so that the upper level can correctly free up
 654          * things.
 655          */
 656         scsi_setup_cmd_retry(scmd);
 657         list_move_tail(&scmd->eh_entry, done_q);
 658 }
 659
 660 /**
 661  * scsi_eh_get_sense - Get device sense data.
 662  * @work_q:     Queue of commands to process.
 663  * @done_q:     Queue of proccessed commands..
 664  *
 665  * Description:
 666  *    See if we need to request sense information.  if so, then get it
 667  *    now, so we have a better idea of what to do.
 668  *
 669  * Notes:
 670  *    This has the unfortunate side effect that if a shost adapter does
 671  *    not automatically request sense information, that we end up shutting
 672  *    it down before we request it.
 673  *
 674  *    All drivers should request sense information internally these days,
 675  *    so for now all I have to say is tough noogies if you end up in here.
 676  *
 677  *    XXX: Long term this code should go away, but that needs an audit of
 678  *         all LLDDs first.
 679  **/
 680 static int scsi_eh_get_sense(struct list_head *work_q,
 681                              struct list_head *done_q)
 682 {
 683         struct list_head *lh, *lh_sf;
 684         struct scsi_cmnd *scmd;
 685         int rtn;
 686
 687         list_for_each_safe(lh, lh_sf, work_q) {
 688                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 689                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
 690                     SCSI_SENSE_VALID(scmd))
 691                         continue;
 692
 693                 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
 694                                                   " for id: %d\n",
 695                                                   current->comm,
 696                                                   scmd->device->id));
 697                 rtn = scsi_request_sense(scmd);
 698                 if (rtn != SUCCESS)
 699                         continue;
 700
 701                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 702                                                   " result %x\n", scmd,
 703                                                   scmd->result));
 704                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 705
 706                 rtn = scsi_decide_disposition(scmd);
 707
 708                 /*
 709                  * if the result was normal, then just pass it along to the
 710                  * upper level.
 711                  */
 712                 if (rtn == SUCCESS)
 713                         /* we don't want this command reissued, just
 714                          * finished with the sense data, so set
 715                          * retries to the max allowed to ensure it
 716                          * won't get reissued */
 717                         scmd->retries = scmd->allowed;
 718                 else if (rtn != NEEDS_RETRY)
 719                         continue;
 720
 721                 scsi_eh_finish_cmd(scmd, done_q);
 722         }
 723
 724         return list_empty(work_q);
 725 }
 726
 727 /**
 728  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 729  * @scmd:       SCSI cmd to abort from Lower Level.
 730  *
 731  * Notes:
 732  *    This function will not return until the user's completion function
 733  *    has been called.  there is no timeout on this operation.  if the
 734  *    author of the low-level driver wishes this operation to be timed,
 735  *    they can provide this facility themselves.  helper functions in
 736  *    scsi_error.c can be supplied to make this easier to do.
 737  **/
 738 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 739 {
 740         unsigned long flags;
 741         int rtn = FAILED;
 742
 743         if (!scmd->device->host->hostt->eh_abort_handler)
 744                 return rtn;
 745
 746         /*
 747          * scsi_done was called just after the command timed out and before
 748          * we had a chance to process it. (db)
 749          */
 750         if (scmd->serial_number == 0)
 751                 return SUCCESS;
 752
 753         scmd->owner = SCSI_OWNER_LOWLEVEL;
 754
 755         spin_lock_irqsave(scmd->device->host->host_lock, flags);
 756         rtn = scmd->device->host->hostt->eh_abort_handler(scmd);
 757         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 758
 759         return rtn;
 760 }
 761
 762 /**
 763  * scsi_eh_tur - Send TUR to device.
 764  * @scmd:       Scsi cmd to send TUR
 765  *
 766  * Return value:
 767  *    0 - Device is ready. 1 - Device NOT ready.
 768  **/
 769 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 770 {
 771         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 772         int retry_cnt = 1, rtn;
 773
 774 retry_tur:
 775         memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
 776
 777         /*
 778          * zero the sense buffer.  the scsi spec mandates that any
 779          * untransferred sense data should be interpreted as being zero.
 780          */
 781         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 782
 783         scmd->request_buffer = NULL;
 784         scmd->request_bufflen = 0;
 785         scmd->use_sg = 0;
 786         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 787         scmd->underflow = 0;
 788         scmd->sc_data_direction = DMA_NONE;
 789
 790         rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
 791
 792         /*
 793          * when we eventually call scsi_finish, we really wish to complete
 794          * the original request, so let's restore the original data. (db)
 795          */
 796         scsi_setup_cmd_retry(scmd);
 797
 798         /*
 799          * hey, we are done.  let's look to see what happened.
 800          */
 801         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 802                 __FUNCTION__, scmd, rtn));
 803         if (rtn == SUCCESS)
 804                 return 0;
 805         else if (rtn == NEEDS_RETRY)
 806                 if (retry_cnt--)
 807                         goto retry_tur;
 808         return 1;
 809 }
 810
 811 /**
 812  * scsi_eh_abort_cmds - abort canceled commands.
 813  * @shost:      scsi host being recovered.
 814  * @eh_done_q:  list_head for processed commands.
 815  *
 816  * Decription:
 817  *    Try and see whether or not it makes sense to try and abort the
 818  *    running command.  this only works out to be the case if we have one
 819  *    command that has timed out.  if the command simply failed, it makes
 820  *    no sense to try and abort the command, since as far as the shost
 821  *    adapter is concerned, it isn't running.
 822  **/
 823 static int scsi_eh_abort_cmds(struct list_head *work_q,
 824                               struct list_head *done_q)
 825 {
 826         struct list_head *lh, *lh_sf;
 827         struct scsi_cmnd *scmd;
 828         int rtn;
 829
 830         list_for_each_safe(lh, lh_sf, work_q) {
 831                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 832                 if (!scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD))
 833                         continue;
 834                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 835                                                   "0x%p\n", current->comm,
 836                                                   scmd));
 837                 rtn = scsi_try_to_abort_cmd(scmd);
 838                 if (rtn == SUCCESS) {
 839                         scsi_eh_eflags_clr(scmd,  SCSI_EH_CANCEL_CMD);
 840                         if (!scsi_device_online(scmd->device) ||
 841                             !scsi_eh_tur(scmd)) {
 842                                 scsi_eh_finish_cmd(scmd, done_q);
 843                         }
 844
 845                 } else
 846                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 847                                                           " cmd failed:"
 848                                                           "0x%p\n",
 849                                                           current->comm,
 850                                                           scmd));
 851         }
 852
 853         return list_empty(work_q);
 854 }
 855
 856 /**
 857  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 858  * @scmd:       SCSI cmd used to send BDR
 859  *
 860  * Notes:
 861  *    There is no timeout for this operation.  if this operation is
 862  *    unreliable for a given host, then the host itself needs to put a
 863  *    timer on it, and set the host back to a consistent state prior to
 864  *    returning.
 865  **/
 866 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 867 {
 868         unsigned long flags;
 869         int rtn = FAILED;
 870
 871         if (!scmd->device->host->hostt->eh_device_reset_handler)
 872                 return rtn;
 873
 874         scmd->owner = SCSI_OWNER_LOWLEVEL;
 875
 876         spin_lock_irqsave(scmd->device->host->host_lock, flags);
 877         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 878         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 879
 880         if (rtn == SUCCESS) {
 881                 scmd->device->was_reset = 1;
 882                 scmd->device->expecting_cc_ua = 1;
 883         }
 884
 885         return rtn;
 886 }
 887
 888 /**
 889  * scsi_eh_try_stu - Send START_UNIT to device.
 890  * @scmd:       Scsi cmd to send START_UNIT
 891  *
 892  * Return value:
 893  *    0 - Device is ready. 1 - Device NOT ready.
 894  **/
 895 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 896 {
 897         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 898         int rtn;
 899
 900         if (!scmd->device->allow_restart)
 901                 return 1;
 902
 903         memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
 904
 905         /*
 906          * zero the sense buffer.  the scsi spec mandates that any
 907          * untransferred sense data should be interpreted as being zero.
 908          */
 909         memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
 910
 911         scmd->request_buffer = NULL;
 912         scmd->request_bufflen = 0;
 913         scmd->use_sg = 0;
 914         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 915         scmd->underflow = 0;
 916         scmd->sc_data_direction = DMA_NONE;
 917
 918         rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
 919
 920         /*
 921          * when we eventually call scsi_finish, we really wish to complete
 922          * the original request, so let's restore the original data. (db)
 923          */
 924         scsi_setup_cmd_retry(scmd);
 925
 926         /*
 927          * hey, we are done.  let's look to see what happened.
 928          */
 929         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 930                 __FUNCTION__, scmd, rtn));
 931         if (rtn == SUCCESS)
 932                 return 0;
 933         return 1;
 934 }
 935
 936  /**
 937  * scsi_eh_stu - send START_UNIT if needed
 938  * @shost:      scsi host being recovered.
 939  * @eh_done_q:  list_head for processed commands.
 940  *
 941  * Notes:
 942  *    If commands are failing due to not ready, initializing command required,
 943  *      try revalidating the device, which will end up sending a start unit.
 944  **/
 945 static int scsi_eh_stu(struct Scsi_Host *shost,
 946                               struct list_head *work_q,
 947                               struct list_head *done_q)
 948 {
 949         struct list_head *lh, *lh_sf;
 950         struct scsi_cmnd *scmd, *stu_scmd;
 951         struct scsi_device *sdev;
 952
 953         shost_for_each_device(sdev, shost) {
 954                 stu_scmd = NULL;
 955                 list_for_each_entry(scmd, work_q, eh_entry)
 956                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 957                             scsi_check_sense(scmd) == FAILED ) {
 958                                 stu_scmd = scmd;
 959                                 break;
 960                         }
 961
 962                 if (!stu_scmd)
 963                         continue;
 964
 965                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 966                                                   " 0x%p\n", current->comm, sdev));
 967
 968                 if (!scsi_eh_try_stu(stu_scmd)) {
 969                         if (!scsi_device_online(sdev) ||
 970                             !scsi_eh_tur(stu_scmd)) {
 971                                 list_for_each_safe(lh, lh_sf, work_q) {
 972                                         scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
 973                                         if (scmd->device == sdev)
 974                                                 scsi_eh_finish_cmd(scmd, done_q);
 975                                 }
 976                         }
 977                 } else {
 978                         SCSI_LOG_ERROR_RECOVERY(3,
 979                                                 printk("%s: START_UNIT failed to sdev:"
 980                                                        " 0x%p\n", current->comm, sdev));
 981                 }
 982         }
 983
 984         return list_empty(work_q);
 985 }
 986
 987
 988 /**
 989  * scsi_eh_bus_device_reset - send bdr if needed
 990  * @shost:      scsi host being recovered.
 991  * @eh_done_q:  list_head for processed commands.
 992  *
 993  * Notes:
 994  *    Try a bus device reset.  still, look to see whether we have multiple
 995  *    devices that are jammed or not - if we have multiple devices, it
 996  *    makes no sense to try bus_device_reset - we really would need to try
 997  *    a bus_reset instead.
 998  **/
 999 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1000                                     struct list_head *work_q,
1001                                     struct list_head *done_q)
1002 {
1003         struct list_head *lh, *lh_sf;
1004         struct scsi_cmnd *scmd, *bdr_scmd;
1005         struct scsi_device *sdev;
1006         int rtn;
1007
1008         shost_for_each_device(sdev, shost) {
1009                 bdr_scmd = NULL;
1010                 list_for_each_entry(scmd, work_q, eh_entry)
1011                         if (scmd->device == sdev) {
1012                                 bdr_scmd = scmd;
1013                                 break;
1014                         }
1015
1016                 if (!bdr_scmd)
1017                         continue;
1018
1019                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1020                                                   " 0x%p\n", current->comm,
1021                                                   sdev));
1022                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1023                 if (rtn == SUCCESS) {
1024                         if (!scsi_device_online(sdev) ||
1025                             !scsi_eh_tur(bdr_scmd)) {
1026                                 list_for_each_safe(lh, lh_sf,
1027                                                    work_q) {
1028                                         scmd = list_entry(lh, struct
1029                                                           scsi_cmnd,
1030                                                           eh_entry);
1031                                         if (scmd->device == sdev)
1032                                                 scsi_eh_finish_cmd(scmd,
1033                                                                    done_q);
1034                                 }
1035                         }
1036                 } else {
1037                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1038                                                           " failed sdev:"
1039                                                           "0x%p\n",
1040                                                           current->comm,
1041                                                            sdev));
1042                 }
1043         }
1044
1045         return list_empty(work_q);
1046 }
1047
1048 /**
1049  * scsi_try_bus_reset - ask host to perform a bus reset
1050  * @scmd:       SCSI cmd to send bus reset.
1051  **/
1052 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
1053 {
1054         unsigned long flags;
1055         int rtn;
1056
1057         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
1058                                           __FUNCTION__));
1059         scmd->owner = SCSI_OWNER_LOWLEVEL;
1060
1061         if (!scmd->device->host->hostt->eh_bus_reset_handler)
1062                 return FAILED;
1063
1064         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1065         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
1066         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1067
1068         if (rtn == SUCCESS) {
1069                 if (!scmd->device->host->hostt->skip_settle_delay)
1070                         ssleep(BUS_RESET_SETTLE_TIME);
1071                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1072                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1073                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1074         }
1075
1076         return rtn;
1077 }
1078
1079 /**
1080  * scsi_try_host_reset - ask host adapter to reset itself
1081  * @scmd:       SCSI cmd to send hsot reset.
1082  **/
1083 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
1084 {
1085         unsigned long flags;
1086         int rtn;
1087
1088         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
1089                                           __FUNCTION__));
1090         scmd->owner = SCSI_OWNER_LOWLEVEL;
1091
1092         if (!scmd->device->host->hostt->eh_host_reset_handler)
1093                 return FAILED;
1094
1095         spin_lock_irqsave(scmd->device->host->host_lock, flags);
1096         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
1097         spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1098
1099         if (rtn == SUCCESS) {
1100                 if (!scmd->device->host->hostt->skip_settle_delay)
1101                         ssleep(HOST_RESET_SETTLE_TIME);
1102                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
1103                 scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
1104                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
1105         }
1106
1107         return rtn;
1108 }
1109
1110 /**
1111  * scsi_eh_bus_reset - send a bus reset
1112  * @shost:      scsi host being recovered.
1113  * @eh_done_q:  list_head for processed commands.
1114  **/
1115 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1116                              struct list_head *work_q,
1117                              struct list_head *done_q)
1118 {
1119         struct list_head *lh, *lh_sf;
1120         struct scsi_cmnd *scmd;
1121         struct scsi_cmnd *chan_scmd;
1122         unsigned int channel;
1123         int rtn;
1124
1125         /*
1126          * we really want to loop over the various channels, and do this on
1127          * a channel by channel basis.  we should also check to see if any
1128          * of the failed commands are on soft_reset devices, and if so, skip
1129          * the reset.
1130          */
1131
1132         for (channel = 0; channel <= shost->max_channel; channel++) {
1133                 chan_scmd = NULL;
1134                 list_for_each_entry(scmd, work_q, eh_entry) {
1135                         if (channel == scmd->device->channel) {
1136                                 chan_scmd = scmd;
1137                                 break;
1138                                 /*
1139                                  * FIXME add back in some support for
1140                                  * soft_reset devices.
1141                                  */
1142                         }
1143                 }
1144
1145                 if (!chan_scmd)
1146                         continue;
1147                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1148                                                   " %d\n", current->comm,
1149                                                   channel));
1150                 rtn = scsi_try_bus_reset(chan_scmd);
1151                 if (rtn == SUCCESS) {
1152                         list_for_each_safe(lh, lh_sf, work_q) {
1153                                 scmd = list_entry(lh, struct scsi_cmnd,
1154                                                   eh_entry);
1155                                 if (channel == scmd->device->channel)
1156                                         if (!scsi_device_online(scmd->device) ||
1157                                             !scsi_eh_tur(scmd))
1158                                                 scsi_eh_finish_cmd(scmd,
1159                                                                    done_q);
1160                         }
1161                 } else {
1162                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1163                                                           " failed chan: %d\n",
1164                                                           current->comm,
1165                                                           channel));
1166                 }
1167         }
1168         return list_empty(work_q);
1169 }
1170
1171 /**
1172  * scsi_eh_host_reset - send a host reset
1173  * @work_q:     list_head for processed commands.
1174  * @done_q:     list_head for processed commands.
1175  **/
1176 static int scsi_eh_host_reset(struct list_head *work_q,
1177                               struct list_head *done_q)
1178 {
1179         int rtn;
1180         struct list_head *lh, *lh_sf;
1181         struct scsi_cmnd *scmd;
1182
1183         if (!list_empty(work_q)) {
1184                 scmd = list_entry(work_q->next,
1185                                   struct scsi_cmnd, eh_entry);
1186
1187                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1188                                                   , current->comm));
1189
1190                 rtn = scsi_try_host_reset(scmd);
1191                 if (rtn == SUCCESS) {
1192                         list_for_each_safe(lh, lh_sf, work_q) {
1193                                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1194                                 if (!scsi_device_online(scmd->device) ||
1195                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1196                                     !scsi_eh_tur(scmd))
1197                                         scsi_eh_finish_cmd(scmd, done_q);
1198                         }
1199                 } else {
1200                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1201                                                           " failed\n",
1202                                                           current->comm));
1203                 }
1204         }
1205         return list_empty(work_q);
1206 }
1207
1208 /**
1209  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1210  * @work_q:     list_head for processed commands.
1211  * @done_q:     list_head for processed commands.
1212  *
1213  **/
1214 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1215                                   struct list_head *done_q)
1216 {
1217         struct list_head *lh, *lh_sf;
1218         struct scsi_cmnd *scmd;
1219
1220         list_for_each_safe(lh, lh_sf, work_q) {
1221                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1222                 printk(KERN_INFO "scsi: Device offlined - not"
1223                                 " ready after error recovery: host"
1224                                 " %d channel %d id %d lun %d\n",
1225                                 scmd->device->host->host_no,
1226                                 scmd->device->channel,
1227                                 scmd->device->id,
1228                                 scmd->device->lun);
1229                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1230                 if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD)) {
1231                         /*
1232                          * FIXME: Handle lost cmds.
1233                          */
1234                 }
1235                 scsi_eh_finish_cmd(scmd, done_q);
1236         }
1237         return;
1238 }
1239
1240 /**
1241  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1242  * @scmd:       SCSI cmd to examine.
1243  *
1244  * Notes:
1245  *    This is *only* called when we are examining the status after sending
1246  *    out the actual data command.  any commands that are queued for error
1247  *    recovery (e.g. test_unit_ready) do *not* come through here.
1248  *
1249  *    When this routine returns failed, it means the error handler thread
1250  *    is woken.  In cases where the error code indicates an error that
1251  *    doesn't require the error handler read (i.e. we don't need to
1252  *    abort/reset), this function should return SUCCESS.
1253  **/
1254 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1255 {
1256         int rtn;
1257
1258         /*
1259          * if the device is offline, then we clearly just pass the result back
1260          * up to the top level.
1261          */
1262         if (!scsi_device_online(scmd->device)) {
1263                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1264                                                   " as SUCCESS\n",
1265                                                   __FUNCTION__));
1266                 return SUCCESS;
1267         }
1268
1269         /*
1270          * first check the host byte, to see if there is anything in there
1271          * that would indicate what we need to do.
1272          */
1273         switch (host_byte(scmd->result)) {
1274         case DID_PASSTHROUGH:
1275                 /*
1276                  * no matter what, pass this through to the upper layer.
1277                  * nuke this special code so that it looks like we are saying
1278                  * did_ok.
1279                  */
1280                 scmd->result &= 0xff00ffff;
1281                 return SUCCESS;
1282         case DID_OK:
1283                 /*
1284                  * looks good.  drop through, and check the next byte.
1285                  */
1286                 break;
1287         case DID_NO_CONNECT:
1288         case DID_BAD_TARGET:
1289         case DID_ABORT:
1290                 /*
1291                  * note - this means that we just report the status back
1292                  * to the top level driver, not that we actually think
1293                  * that it indicates SUCCESS.
1294                  */
1295                 return SUCCESS;
1296                 /*
1297                  * when the low level driver returns did_soft_error,
1298                  * it is responsible for keeping an internal retry counter
1299                  * in order to avoid endless loops (db)
1300                  *
1301                  * actually this is a bug in this function here.  we should
1302                  * be mindful of the maximum number of retries specified
1303                  * and not get stuck in a loop.
1304                  */
1305         case DID_SOFT_ERROR:
1306                 goto maybe_retry;
1307         case DID_IMM_RETRY:
1308                 return NEEDS_RETRY;
1309
1310         case DID_REQUEUE:
1311                 return ADD_TO_MLQUEUE;
1312
1313         case DID_ERROR:
1314                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1315                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1316                         /*
1317                          * execute reservation conflict processing code
1318                          * lower down
1319                          */
1320                         break;
1321                 /* fallthrough */
1322
1323         case DID_BUS_BUSY:
1324         case DID_PARITY:
1325                 goto maybe_retry;
1326         case DID_TIME_OUT:
1327                 /*
1328                  * when we scan the bus, we get timeout messages for
1329                  * these commands if there is no device available.
1330                  * other hosts report did_no_connect for the same thing.
1331                  */
1332                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1333                      scmd->cmnd[0] == INQUIRY)) {
1334                         return SUCCESS;
1335                 } else {
1336                         return FAILED;
1337                 }
1338         case DID_RESET:
1339                 return SUCCESS;
1340         default:
1341                 return FAILED;
1342         }
1343
1344         /*
1345          * next, check the message byte.
1346          */
1347         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1348                 return FAILED;
1349
1350         /*
1351          * check the status byte to see if this indicates anything special.
1352          */
1353         switch (status_byte(scmd->result)) {
1354         case QUEUE_FULL:
1355                 /*
1356                  * the case of trying to send too many commands to a
1357                  * tagged queueing device.
1358                  */
1359         case BUSY:
1360                 /*
1361                  * device can't talk to us at the moment.  Should only
1362                  * occur (SAM-3) when the task queue is empty, so will cause
1363                  * the empty queue handling to trigger a stall in the
1364                  * device.
1365                  */
1366                 return ADD_TO_MLQUEUE;
1367         case GOOD:
1368         case COMMAND_TERMINATED:
1369         case TASK_ABORTED:
1370                 return SUCCESS;
1371         case CHECK_CONDITION:
1372                 rtn = scsi_check_sense(scmd);
1373                 if (rtn == NEEDS_RETRY)
1374                         goto maybe_retry;
1375                 /* if rtn == FAILED, we have no sense information;
1376                  * returning FAILED will wake the error handler thread
1377                  * to collect the sense and redo the decide
1378                  * disposition */
1379                 return rtn;
1380         case CONDITION_GOOD:
1381         case INTERMEDIATE_GOOD:
1382         case INTERMEDIATE_C_GOOD:
1383         case ACA_ACTIVE:
1384                 /*
1385                  * who knows?  FIXME(eric)
1386                  */
1387                 return SUCCESS;
1388
1389         case RESERVATION_CONFLICT:
1390                 printk(KERN_INFO "scsi: reservation conflict: host"
1391                                 " %d channel %d id %d lun %d\n",
1392                        scmd->device->host->host_no, scmd->device->channel,
1393                        scmd->device->id, scmd->device->lun);
1394                 return SUCCESS; /* causes immediate i/o error */
1395         default:
1396                 return FAILED;
1397         }
1398         return FAILED;
1399
1400       maybe_retry:
1401
1402         /* we requeue for retry because the error was retryable, and
1403          * the request was not marked fast fail.  Note that above,
1404          * even if the request is marked fast fail, we still requeue
1405          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1406         if ((++scmd->retries) < scmd->allowed
1407             && !blk_noretry_request(scmd->request)) {
1408                 return NEEDS_RETRY;
1409         } else {
1410                 /*
1411                  * no more retries - report this one back to upper level.
1412                  */
1413                 return SUCCESS;
1414         }
1415 }
1416
1417 /**
1418  * scsi_eh_lock_done - done function for eh door lock request
1419  * @scmd:       SCSI command block for the door lock request
1420  *
1421  * Notes:
1422  *      We completed the asynchronous door lock request, and it has either
1423  *      locked the door or failed.  We must free the command structures
1424  *      associated with this request.
1425  **/
1426 static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
1427 {
1428         struct scsi_request *sreq = scmd->sc_request;
1429
1430         scsi_release_request(sreq);
1431 }
1432
1433
1434 /**
1435  * scsi_eh_lock_door - Prevent medium removal for the specified device
1436  * @sdev:       SCSI device to prevent medium removal
1437  *
1438  * Locking:
1439  *      We must be called from process context; scsi_allocate_request()
1440  *      may sleep.
1441  *
1442  * Notes:
1443  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1444  *      head of the devices request queue, and continue.
1445  *
1446  * Bugs:
1447  *      scsi_allocate_request() may sleep waiting for existing requests to
1448  *      be processed.  However, since we haven't kicked off any request
1449  *      processing for this host, this may deadlock.
1450  *
1451  *      If scsi_allocate_request() fails for what ever reason, we
1452  *      completely forget to lock the door.
1453  **/
1454 static void scsi_eh_lock_door(struct scsi_device *sdev)
1455 {
1456         struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
1457
1458         if (unlikely(!sreq)) {
1459                 printk(KERN_ERR "%s: request allocate failed,"
1460                        "prevent media removal cmd not sent\n", __FUNCTION__);
1461                 return;
1462         }
1463
1464         sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
1465         sreq->sr_cmnd[1] = 0;
1466         sreq->sr_cmnd[2] = 0;
1467         sreq->sr_cmnd[3] = 0;
1468         sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
1469         sreq->sr_cmnd[5] = 0;
1470         sreq->sr_data_direction = DMA_NONE;
1471         sreq->sr_bufflen = 0;
1472         sreq->sr_buffer = NULL;
1473         sreq->sr_allowed = 5;
1474         sreq->sr_done = scsi_eh_lock_done;
1475         sreq->sr_timeout_per_command = 10 * HZ;
1476         sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
1477
1478         scsi_insert_special_req(sreq, 1);
1479 }
1480
1481
1482 /**
1483  * scsi_restart_operations - restart io operations to the specified host.
1484  * @shost:      Host we are restarting.
1485  *
1486  * Notes:
1487  *    When we entered the error handler, we blocked all further i/o to
1488  *    this device.  we need to 'reverse' this process.
1489  **/
1490 static void scsi_restart_operations(struct Scsi_Host *shost)
1491 {
1492         struct scsi_device *sdev;
1493
1494         /*
1495          * If the door was locked, we need to insert a door lock request
1496          * onto the head of the SCSI request queue for the device.  There
1497          * is no point trying to lock the door of an off-line device.
1498          */
1499         shost_for_each_device(sdev, shost) {
1500                 if (scsi_device_online(sdev) && sdev->locked)
1501                         scsi_eh_lock_door(sdev);
1502         }
1503
1504         /*
1505          * next free up anything directly waiting upon the host.  this
1506          * will be requests for character device operations, and also for
1507          * ioctls to queued block devices.
1508          */
1509         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1510                                           __FUNCTION__));
1511
1512         clear_bit(SHOST_RECOVERY, &shost->shost_state);
1513
1514         wake_up(&shost->host_wait);
1515
1516         /*
1517          * finally we need to re-initiate requests that may be pending.  we will
1518          * have had everything blocked while error handling is taking place, and
1519          * now that error recovery is done, we will need to ensure that these
1520          * requests are started.
1521          */
1522         scsi_run_host_queues(shost);
1523 }
1524
1525 /**
1526  * scsi_eh_ready_devs - check device ready state and recover if not.
1527  * @shost:      host to be recovered.
1528  * @eh_done_q:  list_head for processed commands.
1529  *
1530  **/
1531 static void scsi_eh_ready_devs(struct Scsi_Host *shost,
1532                                struct list_head *work_q,
1533                                struct list_head *done_q)
1534 {
1535         if (!scsi_eh_stu(shost, work_q, done_q))
1536                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1537                         if (!scsi_eh_bus_reset(shost, work_q, done_q))
1538                                 if (!scsi_eh_host_reset(work_q, done_q))
1539                                         scsi_eh_offline_sdevs(work_q, done_q);
1540 }
1541
1542 /**
1543  * scsi_eh_flush_done_q - finish processed commands or retry them.
1544  * @done_q:     list_head of processed commands.
1545  *
1546  **/
1547 static void scsi_eh_flush_done_q(struct list_head *done_q)
1548 {
1549         struct list_head *lh, *lh_sf;
1550         struct scsi_cmnd *scmd;
1551
1552         list_for_each_safe(lh, lh_sf, done_q) {
1553                 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1554                 list_del_init(lh);
1555                 if (scsi_device_online(scmd->device) &&
1556                     !blk_noretry_request(scmd->request) &&
1557                     (++scmd->retries < scmd->allowed)) {
1558                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1559                                                           " retry cmd: %p\n",
1560                                                           current->comm,
1561                                                           scmd));
1562                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1563                 } else {
1564                         if (!scmd->result)
1565                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1566                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1567                                                         " cmd: %p\n",
1568                                                         current->comm, scmd));
1569                         scsi_finish_command(scmd);
1570                 }
1571         }
1572 }
1573
1574 /**
1575  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1576  * @shost:      Host to unjam.
1577  *
1578  * Notes:
1579  *    When we come in here, we *know* that all commands on the bus have
1580  *    either completed, failed or timed out.  we also know that no further
1581  *    commands are being sent to the host, so things are relatively quiet
1582  *    and we have freedom to fiddle with things as we wish.
1583  *
1584  *    This is only the *default* implementation.  it is possible for
1585  *    individual drivers to supply their own version of this function, and
1586  *    if the maintainer wishes to do this, it is strongly suggested that
1587  *    this function be taken as a template and modified.  this function
1588  *    was designed to correctly handle problems for about 95% of the
1589  *    different cases out there, and it should always provide at least a
1590  *    reasonable amount of error recovery.
1591  *
1592  *    Any command marked 'failed' or 'timeout' must eventually have
1593  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1594  *    here, so when we restart the host after we return it should have an
1595  *    empty queue.
1596  **/
1597 static void scsi_unjam_host(struct Scsi_Host *shost)
1598 {
1599         unsigned long flags;
1600         LIST_HEAD(eh_work_q);
1601         LIST_HEAD(eh_done_q);
1602
1603         spin_lock_irqsave(shost->host_lock, flags);
1604         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1605         spin_unlock_irqrestore(shost->host_lock, flags);
1606
1607         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1608
1609         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1610                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1611                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1612
1613         scsi_eh_flush_done_q(&eh_done_q);
1614 }
1615
1616 /**
1617  * scsi_error_handler - Handle errors/timeouts of SCSI cmds.
1618  * @data:       Host for which we are running.
1619  *
1620  * Notes:
1621  *    This is always run in the context of a kernel thread.  The idea is
1622  *    that we start this thing up when the kernel starts up (one per host
1623  *    that we detect), and it immediately goes to sleep and waits for some
1624  *    event (i.e. failure).  When this takes place, we have the job of
1625  *    trying to unjam the bus and restarting things.
1626  **/
1627 int scsi_error_handler(void *data)
1628 {
1629         struct Scsi_Host *shost = (struct Scsi_Host *) data;
1630         int rtn;
1631         DECLARE_MUTEX_LOCKED(sem);
1632
1633         /*
1634          *    Flush resources
1635          */
1636
1637         daemonize("scsi_eh_%d", shost->host_no);
1638
1639         current->flags |= PF_NOFREEZE;
1640
1641         shost->eh_wait = &sem;
1642         shost->ehandler = current;
1643
1644         /*
1645          * Wake up the thread that created us.
1646          */
1647         SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
1648                                           " scsi_eh_%d\n",shost->host_no));
1649
1650         complete(shost->eh_notify);
1651
1652         while (1) {
1653                 /*
1654                  * If we get a signal, it means we are supposed to go
1655                  * away and die.  This typically happens if the user is
1656                  * trying to unload a module.
1657                  */
1658                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1659                                                   " scsi_eh_%d"
1660                                                   " sleeping\n",shost->host_no));
1661
1662                 /*
1663                  * Note - we always use down_interruptible with the semaphore
1664                  * even if the module was loaded as part of the kernel.  The
1665                  * reason is that down() will cause this thread to be counted
1666                  * in the load average as a running process, and down
1667                  * interruptible doesn't.  Given that we need to allow this
1668                  * thread to die if the driver was loaded as a module, using
1669                  * semaphores isn't unreasonable.
1670                  */
1671                 down_interruptible(&sem);
1672                 if (shost->eh_kill)
1673                         break;
1674
1675                 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
1676                                                   " scsi_eh_%d waking"
1677                                                   " up\n",shost->host_no));
1678
1679                 shost->eh_active = 1;
1680
1681                 /*
1682                  * We have a host that is failing for some reason.  Figure out
1683                  * what we need to do to get it up and online again (if we can).
1684                  * If we fail, we end up taking the thing offline.
1685                  */
1686                 if (shost->hostt->eh_strategy_handler)
1687                         rtn = shost->hostt->eh_strategy_handler(shost);
1688                 else
1689                         scsi_unjam_host(shost);
1690
1691                 shost->eh_active = 0;
1692
1693                 /*
1694                  * Note - if the above fails completely, the action is to take
1695                  * individual devices offline and flush the queue of any
1696                  * outstanding requests that may have been pending.  When we
1697                  * restart, we restart any I/O to any other devices on the bus
1698                  * which are still online.
1699                  */
1700                 scsi_restart_operations(shost);
1701
1702         }
1703
1704         SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
1705                                           " exiting\n",shost->host_no));
1706
1707         /*
1708          * Make sure that nobody tries to wake us up again.
1709          */
1710         shost->eh_wait = NULL;
1711
1712         /*
1713          * Knock this down too.  From this point on, the host is flying
1714          * without a pilot.  If this is because the module is being unloaded,
1715          * that's fine.  If the user sent a signal to this thing, we are
1716          * potentially in real danger.
1717          */
1718         shost->eh_active = 0;
1719         shost->ehandler = NULL;
1720
1721         /*
1722          * If anyone is waiting for us to exit (i.e. someone trying to unload
1723          * a driver), then wake up that process to let them know we are on
1724          * the way out the door.
1725          */
1726         complete_and_exit(shost->eh_notify, 0);
1727         return 0;
1728 }
1729
1730 /*
1731  * Function:    scsi_report_bus_reset()
1732  *
1733  * Purpose:     Utility function used by low-level drivers to report that
1734  *              they have observed a bus reset on the bus being handled.
1735  *
1736  * Arguments:   shost       - Host in question
1737  *              channel     - channel on which reset was observed.
1738  *
1739  * Returns:     Nothing
1740  *
1741  * Lock status: Host lock must be held.
1742  *
1743  * Notes:       This only needs to be called if the reset is one which
1744  *              originates from an unknown location.  Resets originated
1745  *              by the mid-level itself don't need to call this, but there
1746  *              should be no harm.
1747  *
1748  *              The main purpose of this is to make sure that a CHECK_CONDITION
1749  *              is properly treated.
1750  */
1751 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1752 {
1753         struct scsi_device *sdev;
1754
1755         __shost_for_each_device(sdev, shost) {
1756                 if (channel == sdev->channel) {
1757                         sdev->was_reset = 1;
1758                         sdev->expecting_cc_ua = 1;
1759                 }
1760         }
1761 }
1762 EXPORT_SYMBOL(scsi_report_bus_reset);
1763
1764 /*
1765  * Function:    scsi_report_device_reset()
1766  *
1767  * Purpose:     Utility function used by low-level drivers to report that
1768  *              they have observed a device reset on the device being handled.
1769  *
1770  * Arguments:   shost       - Host in question
1771  *              channel     - channel on which reset was observed
1772  *              target      - target on which reset was observed
1773  *
1774  * Returns:     Nothing
1775  *
1776  * Lock status: Host lock must be held
1777  *
1778  * Notes:       This only needs to be called if the reset is one which
1779  *              originates from an unknown location.  Resets originated
1780  *              by the mid-level itself don't need to call this, but there
1781  *              should be no harm.
1782  *
1783  *              The main purpose of this is to make sure that a CHECK_CONDITION
1784  *              is properly treated.
1785  */
1786 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1787 {
1788         struct scsi_device *sdev;
1789
1790         __shost_for_each_device(sdev, shost) {
1791                 if (channel == sdev->channel &&
1792                     target == sdev->id) {
1793                         sdev->was_reset = 1;
1794                         sdev->expecting_cc_ua = 1;
1795                 }
1796         }
1797 }
1798 EXPORT_SYMBOL(scsi_report_device_reset);
1799
1800 static void
1801 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1802 {
1803 }
1804
1805 /*
1806  * Function:    scsi_reset_provider
1807  *
1808  * Purpose:     Send requested reset to a bus or device at any phase.
1809  *
1810  * Arguments:   device  - device to send reset to
1811  *              flag - reset type (see scsi.h)
1812  *
1813  * Returns:     SUCCESS/FAILURE.
1814  *
1815  * Notes:       This is used by the SCSI Generic driver to provide
1816  *              Bus/Device reset capability.
1817  */
1818 int
1819 scsi_reset_provider(struct scsi_device *dev, int flag)
1820 {
1821         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1822         struct request req;
1823         int rtn;
1824
1825         scmd->request = &req;
1826         memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
1827         scmd->request->rq_status        = RQ_SCSI_BUSY;
1828         scmd->state                     = SCSI_STATE_INITIALIZING;
1829         scmd->owner                     = SCSI_OWNER_MIDLEVEL;
1830
1831         memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
1832
1833         scmd->scsi_done         = scsi_reset_provider_done_command;
1834         scmd->done                      = NULL;
1835         scmd->buffer                    = NULL;
1836         scmd->bufflen                   = 0;
1837         scmd->request_buffer            = NULL;
1838         scmd->request_bufflen           = 0;
1839         scmd->abort_reason              = DID_ABORT;
1840
1841         scmd->cmd_len                   = 0;
1842
1843         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1844         scmd->sc_request                = NULL;
1845         scmd->sc_magic                  = SCSI_CMND_MAGIC;
1846
1847         init_timer(&scmd->eh_timeout);
1848
1849         /*
1850          * Sometimes the command can get back into the timer chain,
1851          * so use the pid as an identifier.
1852          */
1853         scmd->pid                       = 0;
1854
1855         switch (flag) {
1856         case SCSI_TRY_RESET_DEVICE:
1857                 rtn = scsi_try_bus_device_reset(scmd);
1858                 if (rtn == SUCCESS)
1859                         break;
1860                 /* FALLTHROUGH */
1861         case SCSI_TRY_RESET_BUS:
1862                 rtn = scsi_try_bus_reset(scmd);
1863                 if (rtn == SUCCESS)
1864                         break;
1865                 /* FALLTHROUGH */
1866         case SCSI_TRY_RESET_HOST:
1867                 rtn = scsi_try_host_reset(scmd);
1868                 break;
1869         default:
1870                 rtn = FAILED;
1871         }
1872
1873         scsi_delete_timer(scmd);
1874         scsi_next_command(scmd);
1875         return rtn;
1876 }
1877 EXPORT_SYMBOL(scsi_reset_provider);
1878
1879 /**
1880  * scsi_normalize_sense - normalize main elements from either fixed or
1881  *                      descriptor sense data format into a common format.
1882  *
1883  * @sense_buffer:       byte array containing sense data returned by device
1884  * @sb_len:             number of valid bytes in sense_buffer
1885  * @sshdr:              pointer to instance of structure that common
1886  *                      elements are written to.
1887  *
1888  * Notes:
1889  *      The "main elements" from sense data are: response_code, sense_key,
1890  *      asc, ascq and additional_length (only for descriptor format).
1891  *
1892  *      Typically this function can be called after a device has
1893  *      responded to a SCSI command with the CHECK_CONDITION status.
1894  *
1895  * Return value:
1896  *      1 if valid sense data information found, else 0;
1897  **/
1898 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1899                          struct scsi_sense_hdr *sshdr)
1900 {
1901         if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
1902                 return 0;
1903
1904         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1905
1906         sshdr->response_code = (sense_buffer[0] & 0x7f);
1907         if (sshdr->response_code >= 0x72) {
1908                 /*
1909                  * descriptor format
1910                  */
1911                 if (sb_len > 1)
1912                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1913                 if (sb_len > 2)
1914                         sshdr->asc = sense_buffer[2];
1915                 if (sb_len > 3)
1916                         sshdr->ascq = sense_buffer[3];
1917                 if (sb_len > 7)
1918                         sshdr->additional_length = sense_buffer[7];
1919         } else {
1920                 /*
1921                  * fixed format
1922                  */
1923                 if (sb_len > 2)
1924                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1925                 if (sb_len > 7) {
1926                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1927                                          sb_len : (sense_buffer[7] + 8);
1928                         if (sb_len > 12)
1929                                 sshdr->asc = sense_buffer[12];
1930                         if (sb_len > 13)
1931                                 sshdr->ascq = sense_buffer[13];
1932                 }
1933         }
1934
1935         return 1;
1936 }
1937 EXPORT_SYMBOL(scsi_normalize_sense);
1938
1939 int scsi_request_normalize_sense(struct scsi_request *sreq,
1940                                  struct scsi_sense_hdr *sshdr)
1941 {
1942         return scsi_normalize_sense(sreq->sr_sense_buffer,
1943                         sizeof(sreq->sr_sense_buffer), sshdr);
1944 }
1945 EXPORT_SYMBOL(scsi_request_normalize_sense);
1946
1947 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1948                                  struct scsi_sense_hdr *sshdr)
1949 {
1950         return scsi_normalize_sense(cmd->sense_buffer,
1951                         sizeof(cmd->sense_buffer), sshdr);
1952 }
1953 EXPORT_SYMBOL(scsi_command_normalize_sense);
1954
1955 /**
1956  * scsi_sense_desc_find - search for a given descriptor type in
1957  *                      descriptor sense data format.
1958  *
1959  * @sense_buffer:       byte array of descriptor format sense data
1960  * @sb_len:             number of valid bytes in sense_buffer
1961  * @desc_type:          value of descriptor type to find
1962  *                      (e.g. 0 -> information)
1963  *
1964  * Notes:
1965  *      only valid when sense data is in descriptor format
1966  *
1967  * Return value:
1968  *      pointer to start of (first) descriptor if found else NULL
1969  **/
1970 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1971                                 int desc_type)
1972 {
1973         int add_sen_len, add_len, desc_len, k;
1974         const u8 * descp;
1975
1976         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1977                 return NULL;
1978         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1979                 return NULL;
1980         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1981                         add_sen_len : (sb_len - 8);
1982         descp = &sense_buffer[8];
1983         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1984                 descp += desc_len;
1985                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1986                 desc_len = add_len + 2;
1987                 if (descp[0] == desc_type)
1988                         return descp;
1989                 if (add_len < 0) // short descriptor ??
1990                         break;
1991         }
1992         return NULL;
1993 }
1994 EXPORT_SYMBOL(scsi_sense_desc_find);
1995
1996 /**
1997  * scsi_get_sense_info_fld - attempts to get information field from
1998  *                      sense data (either fixed or descriptor format)
1999  *
2000  * @sense_buffer:       byte array of sense data
2001  * @sb_len:             number of valid bytes in sense_buffer
2002  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2003  *                      field will be placed if found.
2004  *
2005  * Return value:
2006  *      1 if information field found, 0 if not found.
2007  **/
2008 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2009                             u64 * info_out)
2010 {
2011         int j;
2012         const u8 * ucp;
2013         u64 ull;
2014
2015         if (sb_len < 7)
2016                 return 0;
2017         switch (sense_buffer[0] & 0x7f) {
2018         case 0x70:
2019         case 0x71:
2020                 if (sense_buffer[0] & 0x80) {
2021                         *info_out = (sense_buffer[3] << 24) +
2022                                     (sense_buffer[4] << 16) +
2023                                     (sense_buffer[5] << 8) + sense_buffer[6];
2024                         return 1;
2025                 } else
2026                         return 0;
2027         case 0x72:
2028         case 0x73:
2029                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2030                                            0 /* info desc */);
2031                 if (ucp && (0xa == ucp[1])) {
2032                         ull = 0;
2033                         for (j = 0; j < 8; ++j) {
2034                                 if (j > 0)
2035                                         ull <<= 8;
2036                                 ull |= ucp[4 + j];
2037                         }
2038                         *info_out = ull;
2039                         return 1;
2040                 } else
2041                         return 0;
2042         default:
2043                 return 0;
2044         }
2045 }
2046 EXPORT_SYMBOL(scsi_get_sense_info_fld);