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/gfp.h>
  20 #include <linux/timer.h>
  21 #include <linux/string.h>
  22 #include <linux/kernel.h>
  23 #include <linux/freezer.h>
  24 #include <linux/kthread.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/delay.h>
  28
  29 #include <scsi/scsi.h>
  30 #include <scsi/scsi_cmnd.h>
  31 #include <scsi/scsi_dbg.h>
  32 #include <scsi/scsi_device.h>
  33 #include <scsi/scsi_eh.h>
  34 #include <scsi/scsi_transport.h>
  35 #include <scsi/scsi_host.h>
  36 #include <scsi/scsi_ioctl.h>
  37
  38 #include "scsi_priv.h"
  39 #include "scsi_logging.h"
  40 #include "scsi_transport_api.h"
  41
  42 #include <trace/events/scsi.h>
  43
  44 #define SENSE_TIMEOUT           (10*HZ)
  45
  46 /*
  47  * These should *probably* be handled by the host itself.
  48  * Since it is allowed to sleep, it probably should.
  49  */
  50 #define BUS_RESET_SETTLE_TIME   (10)
  51 #define HOST_RESET_SETTLE_TIME  (10)
  52
  53 /* called with shost->host_lock held */
  54 void scsi_eh_wakeup(struct Scsi_Host *shost)
  55 {
  56         if (shost->host_busy == shost->host_failed) {
  57                 trace_scsi_eh_wakeup(shost);
  58                 wake_up_process(shost->ehandler);
  59                 SCSI_LOG_ERROR_RECOVERY(5,
  60                                 printk("Waking error handler thread\n"));
  61         }
  62 }
  63
  64 /**
  65  * scsi_schedule_eh - schedule EH for SCSI host
  66  * @shost:      SCSI host to invoke error handling on.
  67  *
  68  * Schedule SCSI EH without scmd.
  69  */
  70 void scsi_schedule_eh(struct Scsi_Host *shost)
  71 {
  72         unsigned long flags;
  73
  74         spin_lock_irqsave(shost->host_lock, flags);
  75
  76         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  77             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  78                 shost->host_eh_scheduled++;
  79                 scsi_eh_wakeup(shost);
  80         }
  81
  82         spin_unlock_irqrestore(shost->host_lock, flags);
  83 }
  84 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  85
  86 /**
  87  * scsi_eh_scmd_add - add scsi cmd to error handling.
  88  * @scmd:       scmd to run eh on.
  89  * @eh_flag:    optional SCSI_EH flag.
  90  *
  91  * Return value:
  92  *      0 on failure.
  93  */
  94 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  95 {
  96         struct Scsi_Host *shost = scmd->device->host;
  97         unsigned long flags;
  98         int ret = 0;
  99
 100         if (!shost->ehandler)
 101                 return 0;
 102
 103         spin_lock_irqsave(shost->host_lock, flags);
 104         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 105                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 106                         goto out_unlock;
 107
 108         ret = 1;
 109         scmd->eh_eflags |= eh_flag;
 110         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 111         shost->host_failed++;
 112         scsi_eh_wakeup(shost);
 113  out_unlock:
 114         spin_unlock_irqrestore(shost->host_lock, flags);
 115         return ret;
 116 }
 117
 118 /**
 119  * scsi_times_out - Timeout function for normal scsi commands.
 120  * @req:        request that is timing out.
 121  *
 122  * Notes:
 123  *     We do not need to lock this.  There is the potential for a race
 124  *     only in that the normal completion handling might run, but if the
 125  *     normal completion function determines that the timer has already
 126  *     fired, then it mustn't do anything.
 127  */
 128 enum blk_eh_timer_return scsi_times_out(struct request *req)
 129 {
 130         struct scsi_cmnd *scmd = req->special;
 131         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 132
 133         trace_scsi_dispatch_cmd_timeout(scmd);
 134         scsi_log_completion(scmd, TIMEOUT_ERROR);
 135
 136         if (scmd->device->host->transportt->eh_timed_out)
 137                 rtn = scmd->device->host->transportt->eh_timed_out(scmd);
 138         else if (scmd->device->host->hostt->eh_timed_out)
 139                 rtn = scmd->device->host->hostt->eh_timed_out(scmd);
 140
 141         if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
 142                      !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 143                 scmd->result |= DID_TIME_OUT << 16;
 144                 rtn = BLK_EH_HANDLED;
 145         }
 146
 147         return rtn;
 148 }
 149
 150 /**
 151  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 152  * @sdev:       Device on which we are performing recovery.
 153  *
 154  * Description:
 155  *     We block until the host is out of error recovery, and then check to
 156  *     see whether the host or the device is offline.
 157  *
 158  * Return value:
 159  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 160  */
 161 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 162 {
 163         int online;
 164
 165         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 166
 167         online = scsi_device_online(sdev);
 168
 169         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
 170                                           online));
 171
 172         return online;
 173 }
 174 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 175
 176 #ifdef CONFIG_SCSI_LOGGING
 177 /**
 178  * scsi_eh_prt_fail_stats - Log info on failures.
 179  * @shost:      scsi host being recovered.
 180  * @work_q:     Queue of scsi cmds to process.
 181  */
 182 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 183                                           struct list_head *work_q)
 184 {
 185         struct scsi_cmnd *scmd;
 186         struct scsi_device *sdev;
 187         int total_failures = 0;
 188         int cmd_failed = 0;
 189         int cmd_cancel = 0;
 190         int devices_failed = 0;
 191
 192         shost_for_each_device(sdev, shost) {
 193                 list_for_each_entry(scmd, work_q, eh_entry) {
 194                         if (scmd->device == sdev) {
 195                                 ++total_failures;
 196                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 197                                         ++cmd_cancel;
 198                                 else
 199                                         ++cmd_failed;
 200                         }
 201                 }
 202
 203                 if (cmd_cancel || cmd_failed) {
 204                         SCSI_LOG_ERROR_RECOVERY(3,
 205                                 sdev_printk(KERN_INFO, sdev,
 206                                             "%s: cmds failed: %d, cancel: %d\n",
 207                                             __func__, cmd_failed,
 208                                             cmd_cancel));
 209                         cmd_cancel = 0;
 210                         cmd_failed = 0;
 211                         ++devices_failed;
 212                 }
 213         }
 214
 215         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 216                                           " devices require eh work\n",
 217                                   total_failures, devices_failed));
 218 }
 219 #endif
 220
 221 /**
 222  * scsi_check_sense - Examine scsi cmd sense
 223  * @scmd:       Cmd to have sense checked.
 224  *
 225  * Return value:
 226  *      SUCCESS or FAILED or NEEDS_RETRY
 227  *
 228  * Notes:
 229  *      When a deferred error is detected the current command has
 230  *      not been executed and needs retrying.
 231  */
 232 static int scsi_check_sense(struct scsi_cmnd *scmd)
 233 {
 234         struct scsi_device *sdev = scmd->device;
 235         struct scsi_sense_hdr sshdr;
 236
 237         if (! scsi_command_normalize_sense(scmd, &sshdr))
 238                 return FAILED;  /* no valid sense data */
 239
 240         if (scsi_sense_is_deferred(&sshdr))
 241                 return NEEDS_RETRY;
 242
 243         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
 244                         sdev->scsi_dh_data->scsi_dh->check_sense) {
 245                 int rc;
 246
 247                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
 248                 if (rc != SCSI_RETURN_NOT_HANDLED)
 249                         return rc;
 250                 /* handler does not care. Drop down to default handling */
 251         }
 252
 253         /*
 254          * Previous logic looked for FILEMARK, EOM or ILI which are
 255          * mainly associated with tapes and returned SUCCESS.
 256          */
 257         if (sshdr.response_code == 0x70) {
 258                 /* fixed format */
 259                 if (scmd->sense_buffer[2] & 0xe0)
 260                         return SUCCESS;
 261         } else {
 262                 /*
 263                  * descriptor format: look for "stream commands sense data
 264                  * descriptor" (see SSC-3). Assume single sense data
 265                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 266                  */
 267                 if ((sshdr.additional_length > 3) &&
 268                     (scmd->sense_buffer[8] == 0x4) &&
 269                     (scmd->sense_buffer[11] & 0xe0))
 270                         return SUCCESS;
 271         }
 272
 273         switch (sshdr.sense_key) {
 274         case NO_SENSE:
 275                 return SUCCESS;
 276         case RECOVERED_ERROR:
 277                 return /* soft_error */ SUCCESS;
 278
 279         case ABORTED_COMMAND:
 280                 if (sshdr.asc == 0x10) /* DIF */
 281                         return SUCCESS;
 282
 283                 return NEEDS_RETRY;
 284         case NOT_READY:
 285         case UNIT_ATTENTION:
 286                 /*
 287                  * if we are expecting a cc/ua because of a bus reset that we
 288                  * performed, treat this just as a retry.  otherwise this is
 289                  * information that we should pass up to the upper-level driver
 290                  * so that we can deal with it there.
 291                  */
 292                 if (scmd->device->expecting_cc_ua) {
 293                         scmd->device->expecting_cc_ua = 0;
 294                         return NEEDS_RETRY;
 295                 }
 296                 /*
 297                  * if the device is in the process of becoming ready, we
 298                  * should retry.
 299                  */
 300                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 301                         return NEEDS_RETRY;
 302                 /*
 303                  * if the device is not started, we need to wake
 304                  * the error handler to start the motor
 305                  */
 306                 if (scmd->device->allow_restart &&
 307                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 308                         return FAILED;
 309
 310                 if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
 311                         scmd_printk(KERN_WARNING, scmd,
 312                                     "Warning! Received an indication that the "
 313                                     "LUN assignments on this target have "
 314                                     "changed. The Linux SCSI layer does not "
 315                                     "automatically remap LUN assignments.\n");
 316                 else if (sshdr.asc == 0x3f)
 317                         scmd_printk(KERN_WARNING, scmd,
 318                                     "Warning! Received an indication that the "
 319                                     "operating parameters on this target have "
 320                                     "changed. The Linux SCSI layer does not "
 321                                     "automatically adjust these parameters.\n");
 322
 323                 if (blk_barrier_rq(scmd->request))
 324                         /*
 325                          * barrier requests should always retry on UA
 326                          * otherwise block will get a spurious error
 327                          */
 328                         return NEEDS_RETRY;
 329                 else
 330                         /*
 331                          * for normal (non barrier) commands, pass the
 332                          * UA upwards for a determination in the
 333                          * completion functions
 334                          */
 335                         return SUCCESS;
 336
 337                 /* these three are not supported */
 338         case COPY_ABORTED:
 339         case VOLUME_OVERFLOW:
 340         case MISCOMPARE:
 341                 return SUCCESS;
 342
 343         case MEDIUM_ERROR:
 344                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 345                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 346                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 347                         return SUCCESS;
 348                 }
 349                 return NEEDS_RETRY;
 350
 351         case HARDWARE_ERROR:
 352                 if (scmd->device->retry_hwerror)
 353                         return ADD_TO_MLQUEUE;
 354                 else
 355                         return SUCCESS;
 356
 357         case ILLEGAL_REQUEST:
 358         case BLANK_CHECK:
 359         case DATA_PROTECT:
 360         default:
 361                 return SUCCESS;
 362         }
 363 }
 364
 365 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
 366 {
 367         struct scsi_host_template *sht = sdev->host->hostt;
 368         struct scsi_device *tmp_sdev;
 369
 370         if (!sht->change_queue_depth ||
 371             sdev->queue_depth >= sdev->max_queue_depth)
 372                 return;
 373
 374         if (time_before(jiffies,
 375             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
 376                 return;
 377
 378         if (time_before(jiffies,
 379             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
 380                 return;
 381
 382         /*
 383          * Walk all devices of a target and do
 384          * ramp up on them.
 385          */
 386         shost_for_each_device(tmp_sdev, sdev->host) {
 387                 if (tmp_sdev->channel != sdev->channel ||
 388                     tmp_sdev->id != sdev->id ||
 389                     tmp_sdev->queue_depth == sdev->max_queue_depth)
 390                         continue;
 391                 /*
 392                  * call back into LLD to increase queue_depth by one
 393                  * with ramp up reason code.
 394                  */
 395                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
 396                                         SCSI_QDEPTH_RAMP_UP);
 397                 sdev->last_queue_ramp_up = jiffies;
 398         }
 399 }
 400
 401 static void scsi_handle_queue_full(struct scsi_device *sdev)
 402 {
 403         struct scsi_host_template *sht = sdev->host->hostt;
 404         struct scsi_device *tmp_sdev;
 405
 406         if (!sht->change_queue_depth)
 407                 return;
 408
 409         shost_for_each_device(tmp_sdev, sdev->host) {
 410                 if (tmp_sdev->channel != sdev->channel ||
 411                     tmp_sdev->id != sdev->id)
 412                         continue;
 413                 /*
 414                  * We do not know the number of commands that were at
 415                  * the device when we got the queue full so we start
 416                  * from the highest possible value and work our way down.
 417                  */
 418                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
 419                                         SCSI_QDEPTH_QFULL);
 420         }
 421 }
 422
 423 /**
 424  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 425  * @scmd:       SCSI cmd to examine.
 426  *
 427  * Notes:
 428  *    This is *only* called when we are examining the status of commands
 429  *    queued during error recovery.  the main difference here is that we
 430  *    don't allow for the possibility of retries here, and we are a lot
 431  *    more restrictive about what we consider acceptable.
 432  */
 433 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 434 {
 435         /*
 436          * first check the host byte, to see if there is anything in there
 437          * that would indicate what we need to do.
 438          */
 439         if (host_byte(scmd->result) == DID_RESET) {
 440                 /*
 441                  * rats.  we are already in the error handler, so we now
 442                  * get to try and figure out what to do next.  if the sense
 443                  * is valid, we have a pretty good idea of what to do.
 444                  * if not, we mark it as FAILED.
 445                  */
 446                 return scsi_check_sense(scmd);
 447         }
 448         if (host_byte(scmd->result) != DID_OK)
 449                 return FAILED;
 450
 451         /*
 452          * next, check the message byte.
 453          */
 454         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 455                 return FAILED;
 456
 457         /*
 458          * now, check the status byte to see if this indicates
 459          * anything special.
 460          */
 461         switch (status_byte(scmd->result)) {
 462         case GOOD:
 463                 scsi_handle_queue_ramp_up(scmd->device);
 464         case COMMAND_TERMINATED:
 465                 return SUCCESS;
 466         case CHECK_CONDITION:
 467                 return scsi_check_sense(scmd);
 468         case CONDITION_GOOD:
 469         case INTERMEDIATE_GOOD:
 470         case INTERMEDIATE_C_GOOD:
 471                 /*
 472                  * who knows?  FIXME(eric)
 473                  */
 474                 return SUCCESS;
 475         case RESERVATION_CONFLICT:
 476                 if (scmd->cmnd[0] == TEST_UNIT_READY)
 477                         /* it is a success, we probed the device and
 478                          * found it */
 479                         return SUCCESS;
 480                 /* otherwise, we failed to send the command */
 481                 return FAILED;
 482         case QUEUE_FULL:
 483                 scsi_handle_queue_full(scmd->device);
 484                 /* fall through */
 485         case BUSY:
 486                 return NEEDS_RETRY;
 487         default:
 488                 return FAILED;
 489         }
 490         return FAILED;
 491 }
 492
 493 /**
 494  * scsi_eh_done - Completion function for error handling.
 495  * @scmd:       Cmd that is done.
 496  */
 497 static void scsi_eh_done(struct scsi_cmnd *scmd)
 498 {
 499         struct completion     *eh_action;
 500
 501         SCSI_LOG_ERROR_RECOVERY(3,
 502                 printk("%s scmd: %p result: %x\n",
 503                         __func__, scmd, scmd->result));
 504
 505         eh_action = scmd->device->host->eh_action;
 506         if (eh_action)
 507                 complete(eh_action);
 508 }
 509
 510 /**
 511  * scsi_try_host_reset - ask host adapter to reset itself
 512  * @scmd:       SCSI cmd to send hsot reset.
 513  */
 514 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 515 {
 516         unsigned long flags;
 517         int rtn;
 518
 519         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
 520                                           __func__));
 521
 522         if (!scmd->device->host->hostt->eh_host_reset_handler)
 523                 return FAILED;
 524
 525         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
 526
 527         if (rtn == SUCCESS) {
 528                 if (!scmd->device->host->hostt->skip_settle_delay)
 529                         ssleep(HOST_RESET_SETTLE_TIME);
 530                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 531                 scsi_report_bus_reset(scmd->device->host,
 532                                       scmd_channel(scmd));
 533                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 534         }
 535
 536         return rtn;
 537 }
 538
 539 /**
 540  * scsi_try_bus_reset - ask host to perform a bus reset
 541  * @scmd:       SCSI cmd to send bus reset.
 542  */
 543 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 544 {
 545         unsigned long flags;
 546         int rtn;
 547
 548         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
 549                                           __func__));
 550
 551         if (!scmd->device->host->hostt->eh_bus_reset_handler)
 552                 return FAILED;
 553
 554         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
 555
 556         if (rtn == SUCCESS) {
 557                 if (!scmd->device->host->hostt->skip_settle_delay)
 558                         ssleep(BUS_RESET_SETTLE_TIME);
 559                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 560                 scsi_report_bus_reset(scmd->device->host,
 561                                       scmd_channel(scmd));
 562                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 563         }
 564
 565         return rtn;
 566 }
 567
 568 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 569 {
 570         sdev->was_reset = 1;
 571         sdev->expecting_cc_ua = 1;
 572 }
 573
 574 /**
 575  * scsi_try_target_reset - Ask host to perform a target reset
 576  * @scmd:       SCSI cmd used to send a target reset
 577  *
 578  * Notes:
 579  *    There is no timeout for this operation.  if this operation is
 580  *    unreliable for a given host, then the host itself needs to put a
 581  *    timer on it, and set the host back to a consistent state prior to
 582  *    returning.
 583  */
 584 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 585 {
 586         unsigned long flags;
 587         int rtn;
 588
 589         if (!scmd->device->host->hostt->eh_target_reset_handler)
 590                 return FAILED;
 591
 592         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
 593         if (rtn == SUCCESS) {
 594                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 595                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 596                                           __scsi_report_device_reset);
 597                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 598         }
 599
 600         return rtn;
 601 }
 602
 603 /**
 604  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 605  * @scmd:       SCSI cmd used to send BDR
 606  *
 607  * Notes:
 608  *    There is no timeout for this operation.  if this operation is
 609  *    unreliable for a given host, then the host itself needs to put a
 610  *    timer on it, and set the host back to a consistent state prior to
 611  *    returning.
 612  */
 613 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 614 {
 615         int rtn;
 616
 617         if (!scmd->device->host->hostt->eh_device_reset_handler)
 618                 return FAILED;
 619
 620         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 621         if (rtn == SUCCESS)
 622                 __scsi_report_device_reset(scmd->device, NULL);
 623         return rtn;
 624 }
 625
 626 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 627 {
 628         if (!scmd->device->host->hostt->eh_abort_handler)
 629                 return FAILED;
 630
 631         return scmd->device->host->hostt->eh_abort_handler(scmd);
 632 }
 633
 634 /**
 635  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 636  * @scmd:       SCSI cmd to abort from Lower Level.
 637  *
 638  * Notes:
 639  *    This function will not return until the user's completion function
 640  *    has been called.  there is no timeout on this operation.  if the
 641  *    author of the low-level driver wishes this operation to be timed,
 642  *    they can provide this facility themselves.  helper functions in
 643  *    scsi_error.c can be supplied to make this easier to do.
 644  */
 645 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 646 {
 647         /*
 648          * scsi_done was called just after the command timed out and before
 649          * we had a chance to process it. (db)
 650          */
 651         if (scmd->serial_number == 0)
 652                 return SUCCESS;
 653         return __scsi_try_to_abort_cmd(scmd);
 654 }
 655
 656 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 657 {
 658         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
 659                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 660                         if (scsi_try_target_reset(scmd) != SUCCESS)
 661                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 662                                         scsi_try_host_reset(scmd);
 663 }
 664
 665 /**
 666  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
 667  * @scmd:       SCSI command structure to hijack
 668  * @ses:        structure to save restore information
 669  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 670  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 671  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 672  *
 673  * This function is used to save a scsi command information before re-execution
 674  * as part of the error recovery process.  If @sense_bytes is 0 the command
 675  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 676  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 677  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 678  */
 679 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 680                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 681 {
 682         struct scsi_device *sdev = scmd->device;
 683
 684         /*
 685          * We need saved copies of a number of fields - this is because
 686          * error handling may need to overwrite these with different values
 687          * to run different commands, and once error handling is complete,
 688          * we will need to restore these values prior to running the actual
 689          * command.
 690          */
 691         ses->cmd_len = scmd->cmd_len;
 692         ses->cmnd = scmd->cmnd;
 693         ses->data_direction = scmd->sc_data_direction;
 694         ses->sdb = scmd->sdb;
 695         ses->next_rq = scmd->request->next_rq;
 696         ses->result = scmd->result;
 697         ses->underflow = scmd->underflow;
 698         ses->prot_op = scmd->prot_op;
 699
 700         scmd->prot_op = SCSI_PROT_NORMAL;
 701         scmd->cmnd = ses->eh_cmnd;
 702         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 703         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 704         scmd->request->next_rq = NULL;
 705
 706         if (sense_bytes) {
 707                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 708                                          sense_bytes);
 709                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 710                             scmd->sdb.length);
 711                 scmd->sdb.table.sgl = &ses->sense_sgl;
 712                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 713                 scmd->sdb.table.nents = 1;
 714                 scmd->cmnd[0] = REQUEST_SENSE;
 715                 scmd->cmnd[4] = scmd->sdb.length;
 716                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 717         } else {
 718                 scmd->sc_data_direction = DMA_NONE;
 719                 if (cmnd) {
 720                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 721                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 722                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 723                 }
 724         }
 725
 726         scmd->underflow = 0;
 727
 728         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 729                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 730                         (sdev->lun << 5 & 0xe0);
 731
 732         /*
 733          * Zero the sense buffer.  The scsi spec mandates that any
 734          * untransferred sense data should be interpreted as being zero.
 735          */
 736         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 737 }
 738 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 739
 740 /**
 741  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
 742  * @scmd:       SCSI command structure to restore
 743  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
 744  *
 745  * Undo any damage done by above scsi_eh_prep_cmnd().
 746  */
 747 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 748 {
 749         /*
 750          * Restore original data
 751          */
 752         scmd->cmd_len = ses->cmd_len;
 753         scmd->cmnd = ses->cmnd;
 754         scmd->sc_data_direction = ses->data_direction;
 755         scmd->sdb = ses->sdb;
 756         scmd->request->next_rq = ses->next_rq;
 757         scmd->result = ses->result;
 758         scmd->underflow = ses->underflow;
 759         scmd->prot_op = ses->prot_op;
 760 }
 761 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 762
 763 /**
 764  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
 765  * @scmd:       SCSI command structure to hijack
 766  * @cmnd:       CDB to send
 767  * @cmnd_size:  size in bytes of @cmnd
 768  * @timeout:    timeout for this request
 769  * @sense_bytes: size of sense data to copy or 0
 770  *
 771  * This function is used to send a scsi command down to a target device
 772  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 773  *
 774  * Return value:
 775  *    SUCCESS or FAILED or NEEDS_RETRY
 776  */
 777 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 778                              int cmnd_size, int timeout, unsigned sense_bytes)
 779 {
 780         struct scsi_device *sdev = scmd->device;
 781         struct Scsi_Host *shost = sdev->host;
 782         DECLARE_COMPLETION_ONSTACK(done);
 783         unsigned long timeleft;
 784         unsigned long flags;
 785         struct scsi_eh_save ses;
 786         int rtn;
 787
 788         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
 789         shost->eh_action = &done;
 790
 791         spin_lock_irqsave(shost->host_lock, flags);
 792         scsi_log_send(scmd);
 793         shost->hostt->queuecommand(scmd, scsi_eh_done);
 794         spin_unlock_irqrestore(shost->host_lock, flags);
 795
 796         timeleft = wait_for_completion_timeout(&done, timeout);
 797
 798         shost->eh_action = NULL;
 799
 800         scsi_log_completion(scmd, SUCCESS);
 801
 802         SCSI_LOG_ERROR_RECOVERY(3,
 803                 printk("%s: scmd: %p, timeleft: %ld\n",
 804                         __func__, scmd, timeleft));
 805
 806         /*
 807          * If there is time left scsi_eh_done got called, and we will
 808          * examine the actual status codes to see whether the command
 809          * actually did complete normally, else tell the host to forget
 810          * about this command.
 811          */
 812         if (timeleft) {
 813                 rtn = scsi_eh_completed_normally(scmd);
 814                 SCSI_LOG_ERROR_RECOVERY(3,
 815                         printk("%s: scsi_eh_completed_normally %x\n",
 816                                __func__, rtn));
 817
 818                 switch (rtn) {
 819                 case SUCCESS:
 820                 case NEEDS_RETRY:
 821                 case FAILED:
 822                         break;
 823                 case ADD_TO_MLQUEUE:
 824                         rtn = NEEDS_RETRY;
 825                         break;
 826                 default:
 827                         rtn = FAILED;
 828                         break;
 829                 }
 830         } else {
 831                 scsi_abort_eh_cmnd(scmd);
 832                 rtn = FAILED;
 833         }
 834
 835         scsi_eh_restore_cmnd(scmd, &ses);
 836         return rtn;
 837 }
 838
 839 /**
 840  * scsi_request_sense - Request sense data from a particular target.
 841  * @scmd:       SCSI cmd for request sense.
 842  *
 843  * Notes:
 844  *    Some hosts automatically obtain this information, others require
 845  *    that we obtain it on our own. This function will *not* return until
 846  *    the command either times out, or it completes.
 847  */
 848 static int scsi_request_sense(struct scsi_cmnd *scmd)
 849 {
 850         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 851 }
 852
 853 /**
 854  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 855  * @scmd:       Original SCSI cmd that eh has finished.
 856  * @done_q:     Queue for processed commands.
 857  *
 858  * Notes:
 859  *    We don't want to use the normal command completion while we are are
 860  *    still handling errors - it may cause other commands to be queued,
 861  *    and that would disturb what we are doing.  Thus we really want to
 862  *    keep a list of pending commands for final completion, and once we
 863  *    are ready to leave error handling we handle completion for real.
 864  */
 865 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 866 {
 867         scmd->device->host->host_failed--;
 868         scmd->eh_eflags = 0;
 869         list_move_tail(&scmd->eh_entry, done_q);
 870 }
 871 EXPORT_SYMBOL(scsi_eh_finish_cmd);
 872
 873 /**
 874  * scsi_eh_get_sense - Get device sense data.
 875  * @work_q:     Queue of commands to process.
 876  * @done_q:     Queue of processed commands.
 877  *
 878  * Description:
 879  *    See if we need to request sense information.  if so, then get it
 880  *    now, so we have a better idea of what to do.
 881  *
 882  * Notes:
 883  *    This has the unfortunate side effect that if a shost adapter does
 884  *    not automatically request sense information, we end up shutting
 885  *    it down before we request it.
 886  *
 887  *    All drivers should request sense information internally these days,
 888  *    so for now all I have to say is tough noogies if you end up in here.
 889  *
 890  *    XXX: Long term this code should go away, but that needs an audit of
 891  *         all LLDDs first.
 892  */
 893 int scsi_eh_get_sense(struct list_head *work_q,
 894                       struct list_head *done_q)
 895 {
 896         struct scsi_cmnd *scmd, *next;
 897         int rtn;
 898
 899         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 900                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 901                     SCSI_SENSE_VALID(scmd))
 902                         continue;
 903
 904                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 905                                                   "%s: requesting sense\n",
 906                                                   current->comm));
 907                 rtn = scsi_request_sense(scmd);
 908                 if (rtn != SUCCESS)
 909                         continue;
 910
 911                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 912                                                   " result %x\n", scmd,
 913                                                   scmd->result));
 914                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 915
 916                 rtn = scsi_decide_disposition(scmd);
 917
 918                 /*
 919                  * if the result was normal, then just pass it along to the
 920                  * upper level.
 921                  */
 922                 if (rtn == SUCCESS)
 923                         /* we don't want this command reissued, just
 924                          * finished with the sense data, so set
 925                          * retries to the max allowed to ensure it
 926                          * won't get reissued */
 927                         scmd->retries = scmd->allowed;
 928                 else if (rtn != NEEDS_RETRY)
 929                         continue;
 930
 931                 scsi_eh_finish_cmd(scmd, done_q);
 932         }
 933
 934         return list_empty(work_q);
 935 }
 936 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 937
 938 /**
 939  * scsi_eh_tur - Send TUR to device.
 940  * @scmd:       &scsi_cmnd to send TUR
 941  *
 942  * Return value:
 943  *    0 - Device is ready. 1 - Device NOT ready.
 944  */
 945 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 946 {
 947         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 948         int retry_cnt = 1, rtn;
 949
 950 retry_tur:
 951         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 952
 953         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 954                 __func__, scmd, rtn));
 955
 956         switch (rtn) {
 957         case NEEDS_RETRY:
 958                 if (retry_cnt--)
 959                         goto retry_tur;
 960                 /*FALLTHRU*/
 961         case SUCCESS:
 962                 return 0;
 963         default:
 964                 return 1;
 965         }
 966 }
 967
 968 /**
 969  * scsi_eh_abort_cmds - abort pending commands.
 970  * @work_q:     &list_head for pending commands.
 971  * @done_q:     &list_head for processed commands.
 972  *
 973  * Decription:
 974  *    Try and see whether or not it makes sense to try and abort the
 975  *    running command.  This only works out to be the case if we have one
 976  *    command that has timed out.  If the command simply failed, it makes
 977  *    no sense to try and abort the command, since as far as the shost
 978  *    adapter is concerned, it isn't running.
 979  */
 980 static int scsi_eh_abort_cmds(struct list_head *work_q,
 981                               struct list_head *done_q)
 982 {
 983         struct scsi_cmnd *scmd, *next;
 984         int rtn;
 985
 986         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 987                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 988                         continue;
 989                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 990                                                   "0x%p\n", current->comm,
 991                                                   scmd));
 992                 rtn = scsi_try_to_abort_cmd(scmd);
 993                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
 994                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 995                         if (!scsi_device_online(scmd->device) ||
 996                             rtn == FAST_IO_FAIL ||
 997                             !scsi_eh_tur(scmd)) {
 998                                 scsi_eh_finish_cmd(scmd, done_q);
 999                         }
1000
1001                 } else
1002                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
1003                                                           " cmd failed:"
1004                                                           "0x%p\n",
1005                                                           current->comm,
1006                                                           scmd));
1007         }
1008
1009         return list_empty(work_q);
1010 }
1011
1012 /**
1013  * scsi_eh_try_stu - Send START_UNIT to device.
1014  * @scmd:       &scsi_cmnd to send START_UNIT
1015  *
1016  * Return value:
1017  *    0 - Device is ready. 1 - Device NOT ready.
1018  */
1019 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1020 {
1021         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1022
1023         if (scmd->device->allow_restart) {
1024                 int i, rtn = NEEDS_RETRY;
1025
1026                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1027                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1028
1029                 if (rtn == SUCCESS)
1030                         return 0;
1031         }
1032
1033         return 1;
1034 }
1035
1036  /**
1037  * scsi_eh_stu - send START_UNIT if needed
1038  * @shost:      &scsi host being recovered.
1039  * @work_q:     &list_head for pending commands.
1040  * @done_q:     &list_head for processed commands.
1041  *
1042  * Notes:
1043  *    If commands are failing due to not ready, initializing command required,
1044  *      try revalidating the device, which will end up sending a start unit.
1045  */
1046 static int scsi_eh_stu(struct Scsi_Host *shost,
1047                               struct list_head *work_q,
1048                               struct list_head *done_q)
1049 {
1050         struct scsi_cmnd *scmd, *stu_scmd, *next;
1051         struct scsi_device *sdev;
1052
1053         shost_for_each_device(sdev, shost) {
1054                 stu_scmd = NULL;
1055                 list_for_each_entry(scmd, work_q, eh_entry)
1056                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1057                             scsi_check_sense(scmd) == FAILED ) {
1058                                 stu_scmd = scmd;
1059                                 break;
1060                         }
1061
1062                 if (!stu_scmd)
1063                         continue;
1064
1065                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1066                                                   " 0x%p\n", current->comm, sdev));
1067
1068                 if (!scsi_eh_try_stu(stu_scmd)) {
1069                         if (!scsi_device_online(sdev) ||
1070                             !scsi_eh_tur(stu_scmd)) {
1071                                 list_for_each_entry_safe(scmd, next,
1072                                                           work_q, eh_entry) {
1073                                         if (scmd->device == sdev)
1074                                                 scsi_eh_finish_cmd(scmd, done_q);
1075                                 }
1076                         }
1077                 } else {
1078                         SCSI_LOG_ERROR_RECOVERY(3,
1079                                                 printk("%s: START_UNIT failed to sdev:"
1080                                                        " 0x%p\n", current->comm, sdev));
1081                 }
1082         }
1083
1084         return list_empty(work_q);
1085 }
1086
1087
1088 /**
1089  * scsi_eh_bus_device_reset - send bdr if needed
1090  * @shost:      scsi host being recovered.
1091  * @work_q:     &list_head for pending commands.
1092  * @done_q:     &list_head for processed commands.
1093  *
1094  * Notes:
1095  *    Try a bus device reset.  Still, look to see whether we have multiple
1096  *    devices that are jammed or not - if we have multiple devices, it
1097  *    makes no sense to try bus_device_reset - we really would need to try
1098  *    a bus_reset instead.
1099  */
1100 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1101                                     struct list_head *work_q,
1102                                     struct list_head *done_q)
1103 {
1104         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1105         struct scsi_device *sdev;
1106         int rtn;
1107
1108         shost_for_each_device(sdev, shost) {
1109                 bdr_scmd = NULL;
1110                 list_for_each_entry(scmd, work_q, eh_entry)
1111                         if (scmd->device == sdev) {
1112                                 bdr_scmd = scmd;
1113                                 break;
1114                         }
1115
1116                 if (!bdr_scmd)
1117                         continue;
1118
1119                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1120                                                   " 0x%p\n", current->comm,
1121                                                   sdev));
1122                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1123                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1124                         if (!scsi_device_online(sdev) ||
1125                             rtn == FAST_IO_FAIL ||
1126                             !scsi_eh_tur(bdr_scmd)) {
1127                                 list_for_each_entry_safe(scmd, next,
1128                                                          work_q, eh_entry) {
1129                                         if (scmd->device == sdev)
1130                                                 scsi_eh_finish_cmd(scmd,
1131                                                                    done_q);
1132                                 }
1133                         }
1134                 } else {
1135                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1136                                                           " failed sdev:"
1137                                                           "0x%p\n",
1138                                                           current->comm,
1139                                                            sdev));
1140                 }
1141         }
1142
1143         return list_empty(work_q);
1144 }
1145
1146 /**
1147  * scsi_eh_target_reset - send target reset if needed
1148  * @shost:      scsi host being recovered.
1149  * @work_q:     &list_head for pending commands.
1150  * @done_q:     &list_head for processed commands.
1151  *
1152  * Notes:
1153  *    Try a target reset.
1154  */
1155 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1156                                 struct list_head *work_q,
1157                                 struct list_head *done_q)
1158 {
1159         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1160         unsigned int id = 0;
1161         int rtn;
1162
1163         do {
1164                 tgtr_scmd = NULL;
1165                 list_for_each_entry(scmd, work_q, eh_entry) {
1166                         if (id == scmd_id(scmd)) {
1167                                 tgtr_scmd = scmd;
1168                                 break;
1169                         }
1170                 }
1171                 if (!tgtr_scmd) {
1172                         /* not one exactly equal; find the next highest */
1173                         list_for_each_entry(scmd, work_q, eh_entry) {
1174                                 if (scmd_id(scmd) > id &&
1175                                     (!tgtr_scmd ||
1176                                      scmd_id(tgtr_scmd) > scmd_id(scmd)))
1177                                                 tgtr_scmd = scmd;
1178                         }
1179                 }
1180                 if (!tgtr_scmd)
1181                         /* no more commands, that's it */
1182                         break;
1183
1184                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1185                                                   "to target %d\n",
1186                                                   current->comm, id));
1187                 rtn = scsi_try_target_reset(tgtr_scmd);
1188                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1189                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1190                                 if (id == scmd_id(scmd))
1191                                         if (!scsi_device_online(scmd->device) ||
1192                                             rtn == FAST_IO_FAIL ||
1193                                             !scsi_eh_tur(tgtr_scmd))
1194                                                 scsi_eh_finish_cmd(scmd,
1195                                                                    done_q);
1196                         }
1197                 } else
1198                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1199                                                           " failed target: "
1200                                                           "%d\n",
1201                                                           current->comm, id));
1202                 id++;
1203         } while(id != 0);
1204
1205         return list_empty(work_q);
1206 }
1207
1208 /**
1209  * scsi_eh_bus_reset - send a bus reset
1210  * @shost:      &scsi host being recovered.
1211  * @work_q:     &list_head for pending commands.
1212  * @done_q:     &list_head for processed commands.
1213  */
1214 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1215                              struct list_head *work_q,
1216                              struct list_head *done_q)
1217 {
1218         struct scsi_cmnd *scmd, *chan_scmd, *next;
1219         unsigned int channel;
1220         int rtn;
1221
1222         /*
1223          * we really want to loop over the various channels, and do this on
1224          * a channel by channel basis.  we should also check to see if any
1225          * of the failed commands are on soft_reset devices, and if so, skip
1226          * the reset.
1227          */
1228
1229         for (channel = 0; channel <= shost->max_channel; channel++) {
1230                 chan_scmd = NULL;
1231                 list_for_each_entry(scmd, work_q, eh_entry) {
1232                         if (channel == scmd_channel(scmd)) {
1233                                 chan_scmd = scmd;
1234                                 break;
1235                                 /*
1236                                  * FIXME add back in some support for
1237                                  * soft_reset devices.
1238                                  */
1239                         }
1240                 }
1241
1242                 if (!chan_scmd)
1243                         continue;
1244                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1245                                                   " %d\n", current->comm,
1246                                                   channel));
1247                 rtn = scsi_try_bus_reset(chan_scmd);
1248                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1249                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1250                                 if (channel == scmd_channel(scmd))
1251                                         if (!scsi_device_online(scmd->device) ||
1252                                             rtn == FAST_IO_FAIL ||
1253                                             !scsi_eh_tur(scmd))
1254                                                 scsi_eh_finish_cmd(scmd,
1255                                                                    done_q);
1256                         }
1257                 } else {
1258                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1259                                                           " failed chan: %d\n",
1260                                                           current->comm,
1261                                                           channel));
1262                 }
1263         }
1264         return list_empty(work_q);
1265 }
1266
1267 /**
1268  * scsi_eh_host_reset - send a host reset
1269  * @work_q:     list_head for processed commands.
1270  * @done_q:     list_head for processed commands.
1271  */
1272 static int scsi_eh_host_reset(struct list_head *work_q,
1273                               struct list_head *done_q)
1274 {
1275         struct scsi_cmnd *scmd, *next;
1276         int rtn;
1277
1278         if (!list_empty(work_q)) {
1279                 scmd = list_entry(work_q->next,
1280                                   struct scsi_cmnd, eh_entry);
1281
1282                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1283                                                   , current->comm));
1284
1285                 rtn = scsi_try_host_reset(scmd);
1286                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1287                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1288                                 if (!scsi_device_online(scmd->device) ||
1289                                     rtn == FAST_IO_FAIL ||
1290                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1291                                     !scsi_eh_tur(scmd))
1292                                         scsi_eh_finish_cmd(scmd, done_q);
1293                         }
1294                 } else {
1295                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1296                                                           " failed\n",
1297                                                           current->comm));
1298                 }
1299         }
1300         return list_empty(work_q);
1301 }
1302
1303 /**
1304  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1305  * @work_q:     list_head for processed commands.
1306  * @done_q:     list_head for processed commands.
1307  */
1308 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1309                                   struct list_head *done_q)
1310 {
1311         struct scsi_cmnd *scmd, *next;
1312
1313         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1314                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1315                             "not ready after error recovery\n");
1316                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1317                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1318                         /*
1319                          * FIXME: Handle lost cmds.
1320                          */
1321                 }
1322                 scsi_eh_finish_cmd(scmd, done_q);
1323         }
1324         return;
1325 }
1326
1327 /**
1328  * scsi_noretry_cmd - determinte if command should be failed fast
1329  * @scmd:       SCSI cmd to examine.
1330  */
1331 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1332 {
1333         switch (host_byte(scmd->result)) {
1334         case DID_OK:
1335                 break;
1336         case DID_BUS_BUSY:
1337                 return blk_failfast_transport(scmd->request);
1338         case DID_PARITY:
1339                 return blk_failfast_dev(scmd->request);
1340         case DID_ERROR:
1341                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1342                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1343                         return 0;
1344                 /* fall through */
1345         case DID_SOFT_ERROR:
1346                 return blk_failfast_driver(scmd->request);
1347         }
1348
1349         switch (status_byte(scmd->result)) {
1350         case CHECK_CONDITION:
1351                 /*
1352                  * assume caller has checked sense and determinted
1353                  * the check condition was retryable.
1354                  */
1355                 return blk_failfast_dev(scmd->request);
1356         }
1357
1358         return 0;
1359 }
1360
1361 /**
1362  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1363  * @scmd:       SCSI cmd to examine.
1364  *
1365  * Notes:
1366  *    This is *only* called when we are examining the status after sending
1367  *    out the actual data command.  any commands that are queued for error
1368  *    recovery (e.g. test_unit_ready) do *not* come through here.
1369  *
1370  *    When this routine returns failed, it means the error handler thread
1371  *    is woken.  In cases where the error code indicates an error that
1372  *    doesn't require the error handler read (i.e. we don't need to
1373  *    abort/reset), this function should return SUCCESS.
1374  */
1375 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1376 {
1377         int rtn;
1378
1379         /*
1380          * if the device is offline, then we clearly just pass the result back
1381          * up to the top level.
1382          */
1383         if (!scsi_device_online(scmd->device)) {
1384                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1385                                                   " as SUCCESS\n",
1386                                                   __func__));
1387                 return SUCCESS;
1388         }
1389
1390         /*
1391          * first check the host byte, to see if there is anything in there
1392          * that would indicate what we need to do.
1393          */
1394         switch (host_byte(scmd->result)) {
1395         case DID_PASSTHROUGH:
1396                 /*
1397                  * no matter what, pass this through to the upper layer.
1398                  * nuke this special code so that it looks like we are saying
1399                  * did_ok.
1400                  */
1401                 scmd->result &= 0xff00ffff;
1402                 return SUCCESS;
1403         case DID_OK:
1404                 /*
1405                  * looks good.  drop through, and check the next byte.
1406                  */
1407                 break;
1408         case DID_NO_CONNECT:
1409         case DID_BAD_TARGET:
1410         case DID_ABORT:
1411                 /*
1412                  * note - this means that we just report the status back
1413                  * to the top level driver, not that we actually think
1414                  * that it indicates SUCCESS.
1415                  */
1416                 return SUCCESS;
1417                 /*
1418                  * when the low level driver returns did_soft_error,
1419                  * it is responsible for keeping an internal retry counter
1420                  * in order to avoid endless loops (db)
1421                  *
1422                  * actually this is a bug in this function here.  we should
1423                  * be mindful of the maximum number of retries specified
1424                  * and not get stuck in a loop.
1425                  */
1426         case DID_SOFT_ERROR:
1427                 goto maybe_retry;
1428         case DID_IMM_RETRY:
1429                 return NEEDS_RETRY;
1430
1431         case DID_REQUEUE:
1432                 return ADD_TO_MLQUEUE;
1433         case DID_TRANSPORT_DISRUPTED:
1434                 /*
1435                  * LLD/transport was disrupted during processing of the IO.
1436                  * The transport class is now blocked/blocking,
1437                  * and the transport will decide what to do with the IO
1438                  * based on its timers and recovery capablilities if
1439                  * there are enough retries.
1440                  */
1441                 goto maybe_retry;
1442         case DID_TRANSPORT_FAILFAST:
1443                 /*
1444                  * The transport decided to failfast the IO (most likely
1445                  * the fast io fail tmo fired), so send IO directly upwards.
1446                  */
1447                 return SUCCESS;
1448         case DID_ERROR:
1449                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1450                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1451                         /*
1452                          * execute reservation conflict processing code
1453                          * lower down
1454                          */
1455                         break;
1456                 /* fallthrough */
1457
1458         case DID_BUS_BUSY:
1459         case DID_PARITY:
1460                 goto maybe_retry;
1461         case DID_TIME_OUT:
1462                 /*
1463                  * when we scan the bus, we get timeout messages for
1464                  * these commands if there is no device available.
1465                  * other hosts report did_no_connect for the same thing.
1466                  */
1467                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1468                      scmd->cmnd[0] == INQUIRY)) {
1469                         return SUCCESS;
1470                 } else {
1471                         return FAILED;
1472                 }
1473         case DID_RESET:
1474                 return SUCCESS;
1475         default:
1476                 return FAILED;
1477         }
1478
1479         /*
1480          * next, check the message byte.
1481          */
1482         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1483                 return FAILED;
1484
1485         /*
1486          * check the status byte to see if this indicates anything special.
1487          */
1488         switch (status_byte(scmd->result)) {
1489         case QUEUE_FULL:
1490                 scsi_handle_queue_full(scmd->device);
1491                 /*
1492                  * the case of trying to send too many commands to a
1493                  * tagged queueing device.
1494                  */
1495         case BUSY:
1496                 /*
1497                  * device can't talk to us at the moment.  Should only
1498                  * occur (SAM-3) when the task queue is empty, so will cause
1499                  * the empty queue handling to trigger a stall in the
1500                  * device.
1501                  */
1502                 return ADD_TO_MLQUEUE;
1503         case GOOD:
1504                 scsi_handle_queue_ramp_up(scmd->device);
1505         case COMMAND_TERMINATED:
1506                 return SUCCESS;
1507         case TASK_ABORTED:
1508                 goto maybe_retry;
1509         case CHECK_CONDITION:
1510                 rtn = scsi_check_sense(scmd);
1511                 if (rtn == NEEDS_RETRY)
1512                         goto maybe_retry;
1513                 /* if rtn == FAILED, we have no sense information;
1514                  * returning FAILED will wake the error handler thread
1515                  * to collect the sense and redo the decide
1516                  * disposition */
1517                 return rtn;
1518         case CONDITION_GOOD:
1519         case INTERMEDIATE_GOOD:
1520         case INTERMEDIATE_C_GOOD:
1521         case ACA_ACTIVE:
1522                 /*
1523                  * who knows?  FIXME(eric)
1524                  */
1525                 return SUCCESS;
1526
1527         case RESERVATION_CONFLICT:
1528                 sdev_printk(KERN_INFO, scmd->device,
1529                             "reservation conflict\n");
1530                 return SUCCESS; /* causes immediate i/o error */
1531         default:
1532                 return FAILED;
1533         }
1534         return FAILED;
1535
1536       maybe_retry:
1537
1538         /* we requeue for retry because the error was retryable, and
1539          * the request was not marked fast fail.  Note that above,
1540          * even if the request is marked fast fail, we still requeue
1541          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1542         if ((++scmd->retries) <= scmd->allowed
1543             && !scsi_noretry_cmd(scmd)) {
1544                 return NEEDS_RETRY;
1545         } else {
1546                 /*
1547                  * no more retries - report this one back to upper level.
1548                  */
1549                 return SUCCESS;
1550         }
1551 }
1552
1553 static void eh_lock_door_done(struct request *req, int uptodate)
1554 {
1555         __blk_put_request(req->q, req);
1556 }
1557
1558 /**
1559  * scsi_eh_lock_door - Prevent medium removal for the specified device
1560  * @sdev:       SCSI device to prevent medium removal
1561  *
1562  * Locking:
1563  *      We must be called from process context.
1564  *
1565  * Notes:
1566  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1567  *      head of the devices request queue, and continue.
1568  */
1569 static void scsi_eh_lock_door(struct scsi_device *sdev)
1570 {
1571         struct request *req;
1572
1573         /*
1574          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1575          * request becomes available
1576          */
1577         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1578
1579         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1580         req->cmd[1] = 0;
1581         req->cmd[2] = 0;
1582         req->cmd[3] = 0;
1583         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1584         req->cmd[5] = 0;
1585
1586         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1587
1588         req->cmd_type = REQ_TYPE_BLOCK_PC;
1589         req->cmd_flags |= REQ_QUIET;
1590         req->timeout = 10 * HZ;
1591         req->retries = 5;
1592
1593         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1594 }
1595
1596 /**
1597  * scsi_restart_operations - restart io operations to the specified host.
1598  * @shost:      Host we are restarting.
1599  *
1600  * Notes:
1601  *    When we entered the error handler, we blocked all further i/o to
1602  *    this device.  we need to 'reverse' this process.
1603  */
1604 static void scsi_restart_operations(struct Scsi_Host *shost)
1605 {
1606         struct scsi_device *sdev;
1607         unsigned long flags;
1608
1609         /*
1610          * If the door was locked, we need to insert a door lock request
1611          * onto the head of the SCSI request queue for the device.  There
1612          * is no point trying to lock the door of an off-line device.
1613          */
1614         shost_for_each_device(sdev, shost) {
1615                 if (scsi_device_online(sdev) && sdev->locked)
1616                         scsi_eh_lock_door(sdev);
1617         }
1618
1619         /*
1620          * next free up anything directly waiting upon the host.  this
1621          * will be requests for character device operations, and also for
1622          * ioctls to queued block devices.
1623          */
1624         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1625                                           __func__));
1626
1627         spin_lock_irqsave(shost->host_lock, flags);
1628         if (scsi_host_set_state(shost, SHOST_RUNNING))
1629                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1630                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1631         spin_unlock_irqrestore(shost->host_lock, flags);
1632
1633         wake_up(&shost->host_wait);
1634
1635         /*
1636          * finally we need to re-initiate requests that may be pending.  we will
1637          * have had everything blocked while error handling is taking place, and
1638          * now that error recovery is done, we will need to ensure that these
1639          * requests are started.
1640          */
1641         scsi_run_host_queues(shost);
1642 }
1643
1644 /**
1645  * scsi_eh_ready_devs - check device ready state and recover if not.
1646  * @shost:      host to be recovered.
1647  * @work_q:     &list_head for pending commands.
1648  * @done_q:     &list_head for processed commands.
1649  */
1650 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1651                         struct list_head *work_q,
1652                         struct list_head *done_q)
1653 {
1654         if (!scsi_eh_stu(shost, work_q, done_q))
1655                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1656                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1657                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1658                                         if (!scsi_eh_host_reset(work_q, done_q))
1659                                                 scsi_eh_offline_sdevs(work_q,
1660                                                                       done_q);
1661 }
1662 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1663
1664 /**
1665  * scsi_eh_flush_done_q - finish processed commands or retry them.
1666  * @done_q:     list_head of processed commands.
1667  */
1668 void scsi_eh_flush_done_q(struct list_head *done_q)
1669 {
1670         struct scsi_cmnd *scmd, *next;
1671
1672         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1673                 list_del_init(&scmd->eh_entry);
1674                 if (scsi_device_online(scmd->device) &&
1675                     !scsi_noretry_cmd(scmd) &&
1676                     (++scmd->retries <= scmd->allowed)) {
1677                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1678                                                           " retry cmd: %p\n",
1679                                                           current->comm,
1680                                                           scmd));
1681                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1682                 } else {
1683                         /*
1684                          * If just we got sense for the device (called
1685                          * scsi_eh_get_sense), scmd->result is already
1686                          * set, do not set DRIVER_TIMEOUT.
1687                          */
1688                         if (!scmd->result)
1689                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1690                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1691                                                         " cmd: %p\n",
1692                                                         current->comm, scmd));
1693                         scsi_finish_command(scmd);
1694                 }
1695         }
1696 }
1697 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1698
1699 /**
1700  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1701  * @shost:      Host to unjam.
1702  *
1703  * Notes:
1704  *    When we come in here, we *know* that all commands on the bus have
1705  *    either completed, failed or timed out.  we also know that no further
1706  *    commands are being sent to the host, so things are relatively quiet
1707  *    and we have freedom to fiddle with things as we wish.
1708  *
1709  *    This is only the *default* implementation.  it is possible for
1710  *    individual drivers to supply their own version of this function, and
1711  *    if the maintainer wishes to do this, it is strongly suggested that
1712  *    this function be taken as a template and modified.  this function
1713  *    was designed to correctly handle problems for about 95% of the
1714  *    different cases out there, and it should always provide at least a
1715  *    reasonable amount of error recovery.
1716  *
1717  *    Any command marked 'failed' or 'timeout' must eventually have
1718  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1719  *    here, so when we restart the host after we return it should have an
1720  *    empty queue.
1721  */
1722 static void scsi_unjam_host(struct Scsi_Host *shost)
1723 {
1724         unsigned long flags;
1725         LIST_HEAD(eh_work_q);
1726         LIST_HEAD(eh_done_q);
1727
1728         spin_lock_irqsave(shost->host_lock, flags);
1729         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1730         spin_unlock_irqrestore(shost->host_lock, flags);
1731
1732         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1733
1734         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1735                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1736                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1737
1738         scsi_eh_flush_done_q(&eh_done_q);
1739 }
1740
1741 /**
1742  * scsi_error_handler - SCSI error handler thread
1743  * @data:       Host for which we are running.
1744  *
1745  * Notes:
1746  *    This is the main error handling loop.  This is run as a kernel thread
1747  *    for every SCSI host and handles all error handling activity.
1748  */
1749 int scsi_error_handler(void *data)
1750 {
1751         struct Scsi_Host *shost = data;
1752
1753         /*
1754          * We use TASK_INTERRUPTIBLE so that the thread is not
1755          * counted against the load average as a running process.
1756          * We never actually get interrupted because kthread_run
1757          * disables signal delivery for the created thread.
1758          */
1759         set_current_state(TASK_INTERRUPTIBLE);
1760         while (!kthread_should_stop()) {
1761                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1762                     shost->host_failed != shost->host_busy) {
1763                         SCSI_LOG_ERROR_RECOVERY(1,
1764                                 printk("Error handler scsi_eh_%d sleeping\n",
1765                                         shost->host_no));
1766                         schedule();
1767                         set_current_state(TASK_INTERRUPTIBLE);
1768                         continue;
1769                 }
1770
1771                 __set_current_state(TASK_RUNNING);
1772                 SCSI_LOG_ERROR_RECOVERY(1,
1773                         printk("Error handler scsi_eh_%d waking up\n",
1774                                 shost->host_no));
1775
1776                 /*
1777                  * We have a host that is failing for some reason.  Figure out
1778                  * what we need to do to get it up and online again (if we can).
1779                  * If we fail, we end up taking the thing offline.
1780                  */
1781                 if (scsi_autopm_get_host(shost) != 0) {
1782                         SCSI_LOG_ERROR_RECOVERY(1,
1783                                 printk(KERN_ERR "Error handler scsi_eh_%d "
1784                                                 "unable to autoresume\n",
1785                                                 shost->host_no));
1786                         continue;
1787                 }
1788
1789                 if (shost->transportt->eh_strategy_handler)
1790                         shost->transportt->eh_strategy_handler(shost);
1791                 else
1792                         scsi_unjam_host(shost);
1793
1794                 /*
1795                  * Note - if the above fails completely, the action is to take
1796                  * individual devices offline and flush the queue of any
1797                  * outstanding requests that may have been pending.  When we
1798                  * restart, we restart any I/O to any other devices on the bus
1799                  * which are still online.
1800                  */
1801                 scsi_restart_operations(shost);
1802                 scsi_autopm_put_host(shost);
1803                 set_current_state(TASK_INTERRUPTIBLE);
1804         }
1805         __set_current_state(TASK_RUNNING);
1806
1807         SCSI_LOG_ERROR_RECOVERY(1,
1808                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1809         shost->ehandler = NULL;
1810         return 0;
1811 }
1812
1813 /*
1814  * Function:    scsi_report_bus_reset()
1815  *
1816  * Purpose:     Utility function used by low-level drivers to report that
1817  *              they have observed a bus reset on the bus being handled.
1818  *
1819  * Arguments:   shost       - Host in question
1820  *              channel     - channel on which reset was observed.
1821  *
1822  * Returns:     Nothing
1823  *
1824  * Lock status: Host lock must be held.
1825  *
1826  * Notes:       This only needs to be called if the reset is one which
1827  *              originates from an unknown location.  Resets originated
1828  *              by the mid-level itself don't need to call this, but there
1829  *              should be no harm.
1830  *
1831  *              The main purpose of this is to make sure that a CHECK_CONDITION
1832  *              is properly treated.
1833  */
1834 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1835 {
1836         struct scsi_device *sdev;
1837
1838         __shost_for_each_device(sdev, shost) {
1839                 if (channel == sdev_channel(sdev))
1840                         __scsi_report_device_reset(sdev, NULL);
1841         }
1842 }
1843 EXPORT_SYMBOL(scsi_report_bus_reset);
1844
1845 /*
1846  * Function:    scsi_report_device_reset()
1847  *
1848  * Purpose:     Utility function used by low-level drivers to report that
1849  *              they have observed a device reset on the device being handled.
1850  *
1851  * Arguments:   shost       - Host in question
1852  *              channel     - channel on which reset was observed
1853  *              target      - target on which reset was observed
1854  *
1855  * Returns:     Nothing
1856  *
1857  * Lock status: Host lock must be held
1858  *
1859  * Notes:       This only needs to be called if the reset is one which
1860  *              originates from an unknown location.  Resets originated
1861  *              by the mid-level itself don't need to call this, but there
1862  *              should be no harm.
1863  *
1864  *              The main purpose of this is to make sure that a CHECK_CONDITION
1865  *              is properly treated.
1866  */
1867 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1868 {
1869         struct scsi_device *sdev;
1870
1871         __shost_for_each_device(sdev, shost) {
1872                 if (channel == sdev_channel(sdev) &&
1873                     target == sdev_id(sdev))
1874                         __scsi_report_device_reset(sdev, NULL);
1875         }
1876 }
1877 EXPORT_SYMBOL(scsi_report_device_reset);
1878
1879 static void
1880 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1881 {
1882 }
1883
1884 /*
1885  * Function:    scsi_reset_provider
1886  *
1887  * Purpose:     Send requested reset to a bus or device at any phase.
1888  *
1889  * Arguments:   device  - device to send reset to
1890  *              flag - reset type (see scsi.h)
1891  *
1892  * Returns:     SUCCESS/FAILURE.
1893  *
1894  * Notes:       This is used by the SCSI Generic driver to provide
1895  *              Bus/Device reset capability.
1896  */
1897 int
1898 scsi_reset_provider(struct scsi_device *dev, int flag)
1899 {
1900         struct scsi_cmnd *scmd;
1901         struct Scsi_Host *shost = dev->host;
1902         struct request req;
1903         unsigned long flags;
1904         int rtn;
1905
1906         if (scsi_autopm_get_host(shost) < 0)
1907                 return FAILED;
1908
1909         scmd = scsi_get_command(dev, GFP_KERNEL);
1910         blk_rq_init(NULL, &req);
1911         scmd->request = &req;
1912
1913         scmd->cmnd = req.cmd;
1914
1915         scmd->scsi_done         = scsi_reset_provider_done_command;
1916         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1917
1918         scmd->cmd_len                   = 0;
1919
1920         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1921
1922         spin_lock_irqsave(shost->host_lock, flags);
1923         shost->tmf_in_progress = 1;
1924         spin_unlock_irqrestore(shost->host_lock, flags);
1925
1926         switch (flag) {
1927         case SCSI_TRY_RESET_DEVICE:
1928                 rtn = scsi_try_bus_device_reset(scmd);
1929                 if (rtn == SUCCESS)
1930                         break;
1931                 /* FALLTHROUGH */
1932         case SCSI_TRY_RESET_TARGET:
1933                 rtn = scsi_try_target_reset(scmd);
1934                 if (rtn == SUCCESS)
1935                         break;
1936                 /* FALLTHROUGH */
1937         case SCSI_TRY_RESET_BUS:
1938                 rtn = scsi_try_bus_reset(scmd);
1939                 if (rtn == SUCCESS)
1940                         break;
1941                 /* FALLTHROUGH */
1942         case SCSI_TRY_RESET_HOST:
1943                 rtn = scsi_try_host_reset(scmd);
1944                 break;
1945         default:
1946                 rtn = FAILED;
1947         }
1948
1949         spin_lock_irqsave(shost->host_lock, flags);
1950         shost->tmf_in_progress = 0;
1951         spin_unlock_irqrestore(shost->host_lock, flags);
1952
1953         /*
1954          * be sure to wake up anyone who was sleeping or had their queue
1955          * suspended while we performed the TMF.
1956          */
1957         SCSI_LOG_ERROR_RECOVERY(3,
1958                 printk("%s: waking up host to restart after TMF\n",
1959                 __func__));
1960
1961         wake_up(&shost->host_wait);
1962
1963         scsi_run_host_queues(shost);
1964
1965         scsi_next_command(scmd);
1966         scsi_autopm_put_host(shost);
1967         return rtn;
1968 }
1969 EXPORT_SYMBOL(scsi_reset_provider);
1970
1971 /**
1972  * scsi_normalize_sense - normalize main elements from either fixed or
1973  *                      descriptor sense data format into a common format.
1974  *
1975  * @sense_buffer:       byte array containing sense data returned by device
1976  * @sb_len:             number of valid bytes in sense_buffer
1977  * @sshdr:              pointer to instance of structure that common
1978  *                      elements are written to.
1979  *
1980  * Notes:
1981  *      The "main elements" from sense data are: response_code, sense_key,
1982  *      asc, ascq and additional_length (only for descriptor format).
1983  *
1984  *      Typically this function can be called after a device has
1985  *      responded to a SCSI command with the CHECK_CONDITION status.
1986  *
1987  * Return value:
1988  *      1 if valid sense data information found, else 0;
1989  */
1990 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1991                          struct scsi_sense_hdr *sshdr)
1992 {
1993         if (!sense_buffer || !sb_len)
1994                 return 0;
1995
1996         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1997
1998         sshdr->response_code = (sense_buffer[0] & 0x7f);
1999
2000         if (!scsi_sense_valid(sshdr))
2001                 return 0;
2002
2003         if (sshdr->response_code >= 0x72) {
2004                 /*
2005                  * descriptor format
2006                  */
2007                 if (sb_len > 1)
2008                         sshdr->sense_key = (sense_buffer[1] & 0xf);
2009                 if (sb_len > 2)
2010                         sshdr->asc = sense_buffer[2];
2011                 if (sb_len > 3)
2012                         sshdr->ascq = sense_buffer[3];
2013                 if (sb_len > 7)
2014                         sshdr->additional_length = sense_buffer[7];
2015         } else {
2016                 /*
2017                  * fixed format
2018                  */
2019                 if (sb_len > 2)
2020                         sshdr->sense_key = (sense_buffer[2] & 0xf);
2021                 if (sb_len > 7) {
2022                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
2023                                          sb_len : (sense_buffer[7] + 8);
2024                         if (sb_len > 12)
2025                                 sshdr->asc = sense_buffer[12];
2026                         if (sb_len > 13)
2027                                 sshdr->ascq = sense_buffer[13];
2028                 }
2029         }
2030
2031         return 1;
2032 }
2033 EXPORT_SYMBOL(scsi_normalize_sense);
2034
2035 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
2036                                  struct scsi_sense_hdr *sshdr)
2037 {
2038         return scsi_normalize_sense(cmd->sense_buffer,
2039                         SCSI_SENSE_BUFFERSIZE, sshdr);
2040 }
2041 EXPORT_SYMBOL(scsi_command_normalize_sense);
2042
2043 /**
2044  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
2045  * @sense_buffer:       byte array of descriptor format sense data
2046  * @sb_len:             number of valid bytes in sense_buffer
2047  * @desc_type:          value of descriptor type to find
2048  *                      (e.g. 0 -> information)
2049  *
2050  * Notes:
2051  *      only valid when sense data is in descriptor format
2052  *
2053  * Return value:
2054  *      pointer to start of (first) descriptor if found else NULL
2055  */
2056 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2057                                 int desc_type)
2058 {
2059         int add_sen_len, add_len, desc_len, k;
2060         const u8 * descp;
2061
2062         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2063                 return NULL;
2064         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2065                 return NULL;
2066         add_sen_len = (add_sen_len < (sb_len - 8)) ?
2067                         add_sen_len : (sb_len - 8);
2068         descp = &sense_buffer[8];
2069         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2070                 descp += desc_len;
2071                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2072                 desc_len = add_len + 2;
2073                 if (descp[0] == desc_type)
2074                         return descp;
2075                 if (add_len < 0) // short descriptor ??
2076                         break;
2077         }
2078         return NULL;
2079 }
2080 EXPORT_SYMBOL(scsi_sense_desc_find);
2081
2082 /**
2083  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2084  * @sense_buffer:       byte array of sense data
2085  * @sb_len:             number of valid bytes in sense_buffer
2086  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2087  *                      field will be placed if found.
2088  *
2089  * Return value:
2090  *      1 if information field found, 0 if not found.
2091  */
2092 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2093                             u64 * info_out)
2094 {
2095         int j;
2096         const u8 * ucp;
2097         u64 ull;
2098
2099         if (sb_len < 7)
2100                 return 0;
2101         switch (sense_buffer[0] & 0x7f) {
2102         case 0x70:
2103         case 0x71:
2104                 if (sense_buffer[0] & 0x80) {
2105                         *info_out = (sense_buffer[3] << 24) +
2106                                     (sense_buffer[4] << 16) +
2107                                     (sense_buffer[5] << 8) + sense_buffer[6];
2108                         return 1;
2109                 } else
2110                         return 0;
2111         case 0x72:
2112         case 0x73:
2113                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2114                                            0 /* info desc */);
2115                 if (ucp && (0xa == ucp[1])) {
2116                         ull = 0;
2117                         for (j = 0; j < 8; ++j) {
2118                                 if (j > 0)
2119                                         ull <<= 8;
2120                                 ull |= ucp[4 + j];
2121                         }
2122                         *info_out = ull;
2123                         return 1;
2124                 } else
2125                         return 0;
2126         default:
2127                 return 0;
2128         }
2129 }
2130 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2131
2132 /**
2133  * scsi_build_sense_buffer - build sense data in a buffer
2134  * @desc:       Sense format (non zero == descriptor format,
2135  *              0 == fixed format)
2136  * @buf:        Where to build sense data
2137  * @key:        Sense key
2138  * @asc:        Additional sense code
2139  * @ascq:       Additional sense code qualifier
2140  *
2141  **/
2142 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2143 {
2144         if (desc) {
2145                 buf[0] = 0x72;  /* descriptor, current */
2146                 buf[1] = key;
2147                 buf[2] = asc;
2148                 buf[3] = ascq;
2149                 buf[7] = 0;
2150         } else {
2151                 buf[0] = 0x70;  /* fixed, current */
2152                 buf[2] = key;
2153                 buf[7] = 0xa;
2154                 buf[12] = asc;
2155                 buf[13] = ascq;
2156         }
2157 }
2158 EXPORT_SYMBOL(scsi_build_sense_buffer);