GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / scsi / scsi_error.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  scsi_error.c Copyright (C) 1997 Eric Youngdale
4  *
5  *  SCSI error/timeout handling
6  *      Initial versions: Eric Youngdale.  Based upon conversations with
7  *                        Leonard Zubkoff and David Miller at Linux Expo,
8  *                        ideas originating from all over the place.
9  *
10  *      Restructured scsi_unjam_host and associated functions.
11  *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
12  *
13  *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
14  *      minor cleanups.
15  *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
16  */
17
18 #include <linux/module.h>
19 #include <linux/sched.h>
20 #include <linux/gfp.h>
21 #include <linux/timer.h>
22 #include <linux/string.h>
23 #include <linux/kernel.h>
24 #include <linux/freezer.h>
25 #include <linux/kthread.h>
26 #include <linux/interrupt.h>
27 #include <linux/blkdev.h>
28 #include <linux/delay.h>
29 #include <linux/jiffies.h>
30
31 #include <scsi/scsi.h>
32 #include <scsi/scsi_cmnd.h>
33 #include <scsi/scsi_dbg.h>
34 #include <scsi/scsi_device.h>
35 #include <scsi/scsi_driver.h>
36 #include <scsi/scsi_eh.h>
37 #include <scsi/scsi_common.h>
38 #include <scsi/scsi_transport.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_ioctl.h>
41 #include <scsi/scsi_dh.h>
42 #include <scsi/scsi_devinfo.h>
43 #include <scsi/sg.h>
44
45 #include "scsi_priv.h"
46 #include "scsi_logging.h"
47 #include "scsi_transport_api.h"
48
49 #include <trace/events/scsi.h>
50
51 #include <asm/unaligned.h>
52
53 /*
54  * These should *probably* be handled by the host itself.
55  * Since it is allowed to sleep, it probably should.
56  */
57 #define BUS_RESET_SETTLE_TIME   (10)
58 #define HOST_RESET_SETTLE_TIME  (10)
59
60 static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
61 static enum scsi_disposition scsi_try_to_abort_cmd(struct scsi_host_template *,
62                                                    struct scsi_cmnd *);
63
64 void scsi_eh_wakeup(struct Scsi_Host *shost)
65 {
66         lockdep_assert_held(shost->host_lock);
67
68         if (scsi_host_busy(shost) == shost->host_failed) {
69                 trace_scsi_eh_wakeup(shost);
70                 wake_up_process(shost->ehandler);
71                 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
72                         "Waking error handler thread\n"));
73         }
74 }
75
76 /**
77  * scsi_schedule_eh - schedule EH for SCSI host
78  * @shost:      SCSI host to invoke error handling on.
79  *
80  * Schedule SCSI EH without scmd.
81  */
82 void scsi_schedule_eh(struct Scsi_Host *shost)
83 {
84         unsigned long flags;
85
86         spin_lock_irqsave(shost->host_lock, flags);
87
88         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
89             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
90                 shost->host_eh_scheduled++;
91                 scsi_eh_wakeup(shost);
92         }
93
94         spin_unlock_irqrestore(shost->host_lock, flags);
95 }
96 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
97
98 static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
99 {
100         if (!shost->last_reset || shost->eh_deadline == -1)
101                 return 0;
102
103         /*
104          * 32bit accesses are guaranteed to be atomic
105          * (on all supported architectures), so instead
106          * of using a spinlock we can as well double check
107          * if eh_deadline has been set to 'off' during the
108          * time_before call.
109          */
110         if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
111             shost->eh_deadline > -1)
112                 return 0;
113
114         return 1;
115 }
116
117 static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
118 {
119         if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
120                 return true;
121
122         return ++cmd->retries <= cmd->allowed;
123 }
124
125 static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
126 {
127         struct scsi_device *sdev = cmd->device;
128         struct Scsi_Host *host = sdev->host;
129
130         if (host->hostt->eh_should_retry_cmd)
131                 return  host->hostt->eh_should_retry_cmd(cmd);
132
133         return true;
134 }
135
136 /**
137  * scmd_eh_abort_handler - Handle command aborts
138  * @work:       command to be aborted.
139  *
140  * Note: this function must be called only for a command that has timed out.
141  * Because the block layer marks a request as complete before it calls
142  * scsi_times_out(), a .scsi_done() call from the LLD for a command that has
143  * timed out do not have any effect. Hence it is safe to call
144  * scsi_finish_command() from this function.
145  */
146 void
147 scmd_eh_abort_handler(struct work_struct *work)
148 {
149         struct scsi_cmnd *scmd =
150                 container_of(work, struct scsi_cmnd, abort_work.work);
151         struct scsi_device *sdev = scmd->device;
152         struct Scsi_Host *shost = sdev->host;
153         enum scsi_disposition rtn;
154         unsigned long flags;
155
156         if (scsi_host_eh_past_deadline(shost)) {
157                 SCSI_LOG_ERROR_RECOVERY(3,
158                         scmd_printk(KERN_INFO, scmd,
159                                     "eh timeout, not aborting\n"));
160                 goto out;
161         }
162
163         SCSI_LOG_ERROR_RECOVERY(3,
164                         scmd_printk(KERN_INFO, scmd,
165                                     "aborting command\n"));
166         rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
167         if (rtn != SUCCESS) {
168                 SCSI_LOG_ERROR_RECOVERY(3,
169                         scmd_printk(KERN_INFO, scmd,
170                                     "cmd abort %s\n",
171                                     (rtn == FAST_IO_FAIL) ?
172                                     "not send" : "failed"));
173                 goto out;
174         }
175         set_host_byte(scmd, DID_TIME_OUT);
176         if (scsi_host_eh_past_deadline(shost)) {
177                 SCSI_LOG_ERROR_RECOVERY(3,
178                         scmd_printk(KERN_INFO, scmd,
179                                     "eh timeout, not retrying "
180                                     "aborted command\n"));
181                 goto out;
182         }
183
184         spin_lock_irqsave(shost->host_lock, flags);
185         list_del_init(&scmd->eh_entry);
186
187         /*
188          * If the abort succeeds, and there is no further
189          * EH action, clear the ->last_reset time.
190          */
191         if (list_empty(&shost->eh_abort_list) &&
192             list_empty(&shost->eh_cmd_q))
193                 if (shost->eh_deadline != -1)
194                         shost->last_reset = 0;
195
196         spin_unlock_irqrestore(shost->host_lock, flags);
197
198         if (!scsi_noretry_cmd(scmd) &&
199             scsi_cmd_retry_allowed(scmd) &&
200             scsi_eh_should_retry_cmd(scmd)) {
201                 SCSI_LOG_ERROR_RECOVERY(3,
202                         scmd_printk(KERN_WARNING, scmd,
203                                     "retry aborted command\n"));
204                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
205         } else {
206                 SCSI_LOG_ERROR_RECOVERY(3,
207                         scmd_printk(KERN_WARNING, scmd,
208                                     "finish aborted command\n"));
209                 scsi_finish_command(scmd);
210         }
211         return;
212
213 out:
214         spin_lock_irqsave(shost->host_lock, flags);
215         list_del_init(&scmd->eh_entry);
216         spin_unlock_irqrestore(shost->host_lock, flags);
217
218         scsi_eh_scmd_add(scmd);
219 }
220
221 /**
222  * scsi_abort_command - schedule a command abort
223  * @scmd:       scmd to abort.
224  *
225  * We only need to abort commands after a command timeout
226  */
227 static int
228 scsi_abort_command(struct scsi_cmnd *scmd)
229 {
230         struct scsi_device *sdev = scmd->device;
231         struct Scsi_Host *shost = sdev->host;
232         unsigned long flags;
233
234         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
235                 /*
236                  * Retry after abort failed, escalate to next level.
237                  */
238                 SCSI_LOG_ERROR_RECOVERY(3,
239                         scmd_printk(KERN_INFO, scmd,
240                                     "previous abort failed\n"));
241                 BUG_ON(delayed_work_pending(&scmd->abort_work));
242                 return FAILED;
243         }
244
245         spin_lock_irqsave(shost->host_lock, flags);
246         if (shost->eh_deadline != -1 && !shost->last_reset)
247                 shost->last_reset = jiffies;
248         BUG_ON(!list_empty(&scmd->eh_entry));
249         list_add_tail(&scmd->eh_entry, &shost->eh_abort_list);
250         spin_unlock_irqrestore(shost->host_lock, flags);
251
252         scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
253         SCSI_LOG_ERROR_RECOVERY(3,
254                 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
255         queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
256         return SUCCESS;
257 }
258
259 /**
260  * scsi_eh_reset - call into ->eh_action to reset internal counters
261  * @scmd:       scmd to run eh on.
262  *
263  * The scsi driver might be carrying internal state about the
264  * devices, so we need to call into the driver to reset the
265  * internal state once the error handler is started.
266  */
267 static void scsi_eh_reset(struct scsi_cmnd *scmd)
268 {
269         if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
270                 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
271                 if (sdrv->eh_reset)
272                         sdrv->eh_reset(scmd);
273         }
274 }
275
276 static void scsi_eh_inc_host_failed(struct rcu_head *head)
277 {
278         struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
279         struct Scsi_Host *shost = scmd->device->host;
280         unsigned long flags;
281
282         spin_lock_irqsave(shost->host_lock, flags);
283         shost->host_failed++;
284         scsi_eh_wakeup(shost);
285         spin_unlock_irqrestore(shost->host_lock, flags);
286 }
287
288 /**
289  * scsi_eh_scmd_add - add scsi cmd to error handling.
290  * @scmd:       scmd to run eh on.
291  */
292 void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
293 {
294         struct Scsi_Host *shost = scmd->device->host;
295         unsigned long flags;
296         int ret;
297
298         WARN_ON_ONCE(!shost->ehandler);
299
300         spin_lock_irqsave(shost->host_lock, flags);
301         if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
302                 ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
303                 WARN_ON_ONCE(ret);
304         }
305         if (shost->eh_deadline != -1 && !shost->last_reset)
306                 shost->last_reset = jiffies;
307
308         scsi_eh_reset(scmd);
309         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
310         spin_unlock_irqrestore(shost->host_lock, flags);
311         /*
312          * Ensure that all tasks observe the host state change before the
313          * host_failed change.
314          */
315         call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
316 }
317
318 /**
319  * scsi_times_out - Timeout function for normal scsi commands.
320  * @req:        request that is timing out.
321  *
322  * Notes:
323  *     We do not need to lock this.  There is the potential for a race
324  *     only in that the normal completion handling might run, but if the
325  *     normal completion function determines that the timer has already
326  *     fired, then it mustn't do anything.
327  */
328 enum blk_eh_timer_return scsi_times_out(struct request *req)
329 {
330         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
331         enum blk_eh_timer_return rtn = BLK_EH_DONE;
332         struct Scsi_Host *host = scmd->device->host;
333
334         trace_scsi_dispatch_cmd_timeout(scmd);
335         scsi_log_completion(scmd, TIMEOUT_ERROR);
336
337         if (host->eh_deadline != -1 && !host->last_reset)
338                 host->last_reset = jiffies;
339
340         if (host->hostt->eh_timed_out)
341                 rtn = host->hostt->eh_timed_out(scmd);
342
343         if (rtn == BLK_EH_DONE) {
344                 /*
345                  * Set the command to complete first in order to prevent a real
346                  * completion from releasing the command while error handling
347                  * is using it. If the command was already completed, then the
348                  * lower level driver beat the timeout handler, and it is safe
349                  * to return without escalating error recovery.
350                  *
351                  * If timeout handling lost the race to a real completion, the
352                  * block layer may ignore that due to a fake timeout injection,
353                  * so return RESET_TIMER to allow error handling another shot
354                  * at this command.
355                  */
356                 if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
357                         return BLK_EH_RESET_TIMER;
358                 if (scsi_abort_command(scmd) != SUCCESS) {
359                         set_host_byte(scmd, DID_TIME_OUT);
360                         scsi_eh_scmd_add(scmd);
361                 }
362         }
363
364         return rtn;
365 }
366
367 /**
368  * scsi_block_when_processing_errors - Prevent cmds from being queued.
369  * @sdev:       Device on which we are performing recovery.
370  *
371  * Description:
372  *     We block until the host is out of error recovery, and then check to
373  *     see whether the host or the device is offline.
374  *
375  * Return value:
376  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
377  */
378 int scsi_block_when_processing_errors(struct scsi_device *sdev)
379 {
380         int online;
381
382         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
383
384         online = scsi_device_online(sdev);
385
386         return online;
387 }
388 EXPORT_SYMBOL(scsi_block_when_processing_errors);
389
390 #ifdef CONFIG_SCSI_LOGGING
391 /**
392  * scsi_eh_prt_fail_stats - Log info on failures.
393  * @shost:      scsi host being recovered.
394  * @work_q:     Queue of scsi cmds to process.
395  */
396 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
397                                           struct list_head *work_q)
398 {
399         struct scsi_cmnd *scmd;
400         struct scsi_device *sdev;
401         int total_failures = 0;
402         int cmd_failed = 0;
403         int cmd_cancel = 0;
404         int devices_failed = 0;
405
406         shost_for_each_device(sdev, shost) {
407                 list_for_each_entry(scmd, work_q, eh_entry) {
408                         if (scmd->device == sdev) {
409                                 ++total_failures;
410                                 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
411                                         ++cmd_cancel;
412                                 else
413                                         ++cmd_failed;
414                         }
415                 }
416
417                 if (cmd_cancel || cmd_failed) {
418                         SCSI_LOG_ERROR_RECOVERY(3,
419                                 shost_printk(KERN_INFO, shost,
420                                             "%s: cmds failed: %d, cancel: %d\n",
421                                             __func__, cmd_failed,
422                                             cmd_cancel));
423                         cmd_cancel = 0;
424                         cmd_failed = 0;
425                         ++devices_failed;
426                 }
427         }
428
429         SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
430                                    "Total of %d commands on %d"
431                                    " devices require eh work\n",
432                                    total_failures, devices_failed));
433 }
434 #endif
435
436  /**
437  * scsi_report_lun_change - Set flag on all *other* devices on the same target
438  *                          to indicate that a UNIT ATTENTION is expected.
439  * @sdev:       Device reporting the UNIT ATTENTION
440  */
441 static void scsi_report_lun_change(struct scsi_device *sdev)
442 {
443         sdev->sdev_target->expecting_lun_change = 1;
444 }
445
446 /**
447  * scsi_report_sense - Examine scsi sense information and log messages for
448  *                     certain conditions, also issue uevents for some of them.
449  * @sdev:       Device reporting the sense code
450  * @sshdr:      sshdr to be examined
451  */
452 static void scsi_report_sense(struct scsi_device *sdev,
453                               struct scsi_sense_hdr *sshdr)
454 {
455         enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
456
457         if (sshdr->sense_key == UNIT_ATTENTION) {
458                 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
459                         evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
460                         sdev_printk(KERN_WARNING, sdev,
461                                     "Inquiry data has changed");
462                 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
463                         evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
464                         scsi_report_lun_change(sdev);
465                         sdev_printk(KERN_WARNING, sdev,
466                                     "Warning! Received an indication that the "
467                                     "LUN assignments on this target have "
468                                     "changed. The Linux SCSI layer does not "
469                                     "automatically remap LUN assignments.\n");
470                 } else if (sshdr->asc == 0x3f)
471                         sdev_printk(KERN_WARNING, sdev,
472                                     "Warning! Received an indication that the "
473                                     "operating parameters on this target have "
474                                     "changed. The Linux SCSI layer does not "
475                                     "automatically adjust these parameters.\n");
476
477                 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
478                         evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
479                         sdev_printk(KERN_WARNING, sdev,
480                                     "Warning! Received an indication that the "
481                                     "LUN reached a thin provisioning soft "
482                                     "threshold.\n");
483                 }
484
485                 if (sshdr->asc == 0x29) {
486                         evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
487                         /*
488                          * Do not print message if it is an expected side-effect
489                          * of runtime PM.
490                          */
491                         if (!sdev->silence_suspend)
492                                 sdev_printk(KERN_WARNING, sdev,
493                                             "Power-on or device reset occurred\n");
494                 }
495
496                 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
497                         evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
498                         sdev_printk(KERN_WARNING, sdev,
499                                     "Mode parameters changed");
500                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
501                         evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
502                         sdev_printk(KERN_WARNING, sdev,
503                                     "Asymmetric access state changed");
504                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
505                         evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
506                         sdev_printk(KERN_WARNING, sdev,
507                                     "Capacity data has changed");
508                 } else if (sshdr->asc == 0x2a)
509                         sdev_printk(KERN_WARNING, sdev,
510                                     "Parameters changed");
511         }
512
513         if (evt_type != SDEV_EVT_MAXBITS) {
514                 set_bit(evt_type, sdev->pending_events);
515                 schedule_work(&sdev->event_work);
516         }
517 }
518
519 /**
520  * scsi_check_sense - Examine scsi cmd sense
521  * @scmd:       Cmd to have sense checked.
522  *
523  * Return value:
524  *      SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
525  *
526  * Notes:
527  *      When a deferred error is detected the current command has
528  *      not been executed and needs retrying.
529  */
530 enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
531 {
532         struct scsi_device *sdev = scmd->device;
533         struct scsi_sense_hdr sshdr;
534
535         if (! scsi_command_normalize_sense(scmd, &sshdr))
536                 return FAILED;  /* no valid sense data */
537
538         scsi_report_sense(sdev, &sshdr);
539
540         if (scsi_sense_is_deferred(&sshdr))
541                 return NEEDS_RETRY;
542
543         if (sdev->handler && sdev->handler->check_sense) {
544                 enum scsi_disposition rc;
545
546                 rc = sdev->handler->check_sense(sdev, &sshdr);
547                 if (rc != SCSI_RETURN_NOT_HANDLED)
548                         return rc;
549                 /* handler does not care. Drop down to default handling */
550         }
551
552         if (scmd->cmnd[0] == TEST_UNIT_READY &&
553             scmd->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER)
554                 /*
555                  * nasty: for mid-layer issued TURs, we need to return the
556                  * actual sense data without any recovery attempt.  For eh
557                  * issued ones, we need to try to recover and interpret
558                  */
559                 return SUCCESS;
560
561         /*
562          * Previous logic looked for FILEMARK, EOM or ILI which are
563          * mainly associated with tapes and returned SUCCESS.
564          */
565         if (sshdr.response_code == 0x70) {
566                 /* fixed format */
567                 if (scmd->sense_buffer[2] & 0xe0)
568                         return SUCCESS;
569         } else {
570                 /*
571                  * descriptor format: look for "stream commands sense data
572                  * descriptor" (see SSC-3). Assume single sense data
573                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
574                  */
575                 if ((sshdr.additional_length > 3) &&
576                     (scmd->sense_buffer[8] == 0x4) &&
577                     (scmd->sense_buffer[11] & 0xe0))
578                         return SUCCESS;
579         }
580
581         switch (sshdr.sense_key) {
582         case NO_SENSE:
583                 return SUCCESS;
584         case RECOVERED_ERROR:
585                 return /* soft_error */ SUCCESS;
586
587         case ABORTED_COMMAND:
588                 if (sshdr.asc == 0x10) /* DIF */
589                         return SUCCESS;
590
591                 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
592                         return ADD_TO_MLQUEUE;
593                 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
594                     sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
595                         return ADD_TO_MLQUEUE;
596
597                 return NEEDS_RETRY;
598         case NOT_READY:
599         case UNIT_ATTENTION:
600                 /*
601                  * if we are expecting a cc/ua because of a bus reset that we
602                  * performed, treat this just as a retry.  otherwise this is
603                  * information that we should pass up to the upper-level driver
604                  * so that we can deal with it there.
605                  */
606                 if (scmd->device->expecting_cc_ua) {
607                         /*
608                          * Because some device does not queue unit
609                          * attentions correctly, we carefully check
610                          * additional sense code and qualifier so as
611                          * not to squash media change unit attention.
612                          */
613                         if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
614                                 scmd->device->expecting_cc_ua = 0;
615                                 return NEEDS_RETRY;
616                         }
617                 }
618                 /*
619                  * we might also expect a cc/ua if another LUN on the target
620                  * reported a UA with an ASC/ASCQ of 3F 0E -
621                  * REPORTED LUNS DATA HAS CHANGED.
622                  */
623                 if (scmd->device->sdev_target->expecting_lun_change &&
624                     sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
625                         return NEEDS_RETRY;
626                 /*
627                  * if the device is in the process of becoming ready, we
628                  * should retry.
629                  */
630                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
631                         return NEEDS_RETRY;
632                 /*
633                  * if the device is not started, we need to wake
634                  * the error handler to start the motor
635                  */
636                 if (scmd->device->allow_restart &&
637                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
638                         return FAILED;
639                 /*
640                  * Pass the UA upwards for a determination in the completion
641                  * functions.
642                  */
643                 return SUCCESS;
644
645                 /* these are not supported */
646         case DATA_PROTECT:
647                 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
648                         /* Thin provisioning hard threshold reached */
649                         set_host_byte(scmd, DID_ALLOC_FAILURE);
650                         return SUCCESS;
651                 }
652                 fallthrough;
653         case COPY_ABORTED:
654         case VOLUME_OVERFLOW:
655         case MISCOMPARE:
656         case BLANK_CHECK:
657                 set_host_byte(scmd, DID_TARGET_FAILURE);
658                 return SUCCESS;
659
660         case MEDIUM_ERROR:
661                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
662                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
663                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
664                         set_host_byte(scmd, DID_MEDIUM_ERROR);
665                         return SUCCESS;
666                 }
667                 return NEEDS_RETRY;
668
669         case HARDWARE_ERROR:
670                 if (scmd->device->retry_hwerror)
671                         return ADD_TO_MLQUEUE;
672                 else
673                         set_host_byte(scmd, DID_TARGET_FAILURE);
674                 fallthrough;
675
676         case ILLEGAL_REQUEST:
677                 if (sshdr.asc == 0x20 || /* Invalid command operation code */
678                     sshdr.asc == 0x21 || /* Logical block address out of range */
679                     sshdr.asc == 0x22 || /* Invalid function */
680                     sshdr.asc == 0x24 || /* Invalid field in cdb */
681                     sshdr.asc == 0x26 || /* Parameter value invalid */
682                     sshdr.asc == 0x27) { /* Write protected */
683                         set_host_byte(scmd, DID_TARGET_FAILURE);
684                 }
685                 return SUCCESS;
686
687         default:
688                 return SUCCESS;
689         }
690 }
691 EXPORT_SYMBOL_GPL(scsi_check_sense);
692
693 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
694 {
695         struct scsi_host_template *sht = sdev->host->hostt;
696         struct scsi_device *tmp_sdev;
697
698         if (!sht->track_queue_depth ||
699             sdev->queue_depth >= sdev->max_queue_depth)
700                 return;
701
702         if (time_before(jiffies,
703             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
704                 return;
705
706         if (time_before(jiffies,
707             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
708                 return;
709
710         /*
711          * Walk all devices of a target and do
712          * ramp up on them.
713          */
714         shost_for_each_device(tmp_sdev, sdev->host) {
715                 if (tmp_sdev->channel != sdev->channel ||
716                     tmp_sdev->id != sdev->id ||
717                     tmp_sdev->queue_depth == sdev->max_queue_depth)
718                         continue;
719
720                 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
721                 sdev->last_queue_ramp_up = jiffies;
722         }
723 }
724
725 static void scsi_handle_queue_full(struct scsi_device *sdev)
726 {
727         struct scsi_host_template *sht = sdev->host->hostt;
728         struct scsi_device *tmp_sdev;
729
730         if (!sht->track_queue_depth)
731                 return;
732
733         shost_for_each_device(tmp_sdev, sdev->host) {
734                 if (tmp_sdev->channel != sdev->channel ||
735                     tmp_sdev->id != sdev->id)
736                         continue;
737                 /*
738                  * We do not know the number of commands that were at
739                  * the device when we got the queue full so we start
740                  * from the highest possible value and work our way down.
741                  */
742                 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
743         }
744 }
745
746 /**
747  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
748  * @scmd:       SCSI cmd to examine.
749  *
750  * Notes:
751  *    This is *only* called when we are examining the status of commands
752  *    queued during error recovery.  the main difference here is that we
753  *    don't allow for the possibility of retries here, and we are a lot
754  *    more restrictive about what we consider acceptable.
755  */
756 static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
757 {
758         /*
759          * first check the host byte, to see if there is anything in there
760          * that would indicate what we need to do.
761          */
762         if (host_byte(scmd->result) == DID_RESET) {
763                 /*
764                  * rats.  we are already in the error handler, so we now
765                  * get to try and figure out what to do next.  if the sense
766                  * is valid, we have a pretty good idea of what to do.
767                  * if not, we mark it as FAILED.
768                  */
769                 return scsi_check_sense(scmd);
770         }
771         if (host_byte(scmd->result) != DID_OK)
772                 return FAILED;
773
774         /*
775          * now, check the status byte to see if this indicates
776          * anything special.
777          */
778         switch (get_status_byte(scmd)) {
779         case SAM_STAT_GOOD:
780                 scsi_handle_queue_ramp_up(scmd->device);
781                 fallthrough;
782         case SAM_STAT_COMMAND_TERMINATED:
783                 return SUCCESS;
784         case SAM_STAT_CHECK_CONDITION:
785                 return scsi_check_sense(scmd);
786         case SAM_STAT_CONDITION_MET:
787         case SAM_STAT_INTERMEDIATE:
788         case SAM_STAT_INTERMEDIATE_CONDITION_MET:
789                 /*
790                  * who knows?  FIXME(eric)
791                  */
792                 return SUCCESS;
793         case SAM_STAT_RESERVATION_CONFLICT:
794                 if (scmd->cmnd[0] == TEST_UNIT_READY)
795                         /* it is a success, we probed the device and
796                          * found it */
797                         return SUCCESS;
798                 /* otherwise, we failed to send the command */
799                 return FAILED;
800         case SAM_STAT_TASK_SET_FULL:
801                 scsi_handle_queue_full(scmd->device);
802                 fallthrough;
803         case SAM_STAT_BUSY:
804                 return NEEDS_RETRY;
805         default:
806                 return FAILED;
807         }
808         return FAILED;
809 }
810
811 /**
812  * scsi_eh_done - Completion function for error handling.
813  * @scmd:       Cmd that is done.
814  */
815 void scsi_eh_done(struct scsi_cmnd *scmd)
816 {
817         struct completion *eh_action;
818
819         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
820                         "%s result: %x\n", __func__, scmd->result));
821
822         eh_action = scmd->device->host->eh_action;
823         if (eh_action)
824                 complete(eh_action);
825 }
826
827 /**
828  * scsi_try_host_reset - ask host adapter to reset itself
829  * @scmd:       SCSI cmd to send host reset.
830  */
831 static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
832 {
833         unsigned long flags;
834         enum scsi_disposition rtn;
835         struct Scsi_Host *host = scmd->device->host;
836         struct scsi_host_template *hostt = host->hostt;
837
838         SCSI_LOG_ERROR_RECOVERY(3,
839                 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
840
841         if (!hostt->eh_host_reset_handler)
842                 return FAILED;
843
844         rtn = hostt->eh_host_reset_handler(scmd);
845
846         if (rtn == SUCCESS) {
847                 if (!hostt->skip_settle_delay)
848                         ssleep(HOST_RESET_SETTLE_TIME);
849                 spin_lock_irqsave(host->host_lock, flags);
850                 scsi_report_bus_reset(host, scmd_channel(scmd));
851                 spin_unlock_irqrestore(host->host_lock, flags);
852         }
853
854         return rtn;
855 }
856
857 /**
858  * scsi_try_bus_reset - ask host to perform a bus reset
859  * @scmd:       SCSI cmd to send bus reset.
860  */
861 static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
862 {
863         unsigned long flags;
864         enum scsi_disposition rtn;
865         struct Scsi_Host *host = scmd->device->host;
866         struct scsi_host_template *hostt = host->hostt;
867
868         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
869                 "%s: Snd Bus RST\n", __func__));
870
871         if (!hostt->eh_bus_reset_handler)
872                 return FAILED;
873
874         rtn = hostt->eh_bus_reset_handler(scmd);
875
876         if (rtn == SUCCESS) {
877                 if (!hostt->skip_settle_delay)
878                         ssleep(BUS_RESET_SETTLE_TIME);
879                 spin_lock_irqsave(host->host_lock, flags);
880                 scsi_report_bus_reset(host, scmd_channel(scmd));
881                 spin_unlock_irqrestore(host->host_lock, flags);
882         }
883
884         return rtn;
885 }
886
887 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
888 {
889         sdev->was_reset = 1;
890         sdev->expecting_cc_ua = 1;
891 }
892
893 /**
894  * scsi_try_target_reset - Ask host to perform a target reset
895  * @scmd:       SCSI cmd used to send a target reset
896  *
897  * Notes:
898  *    There is no timeout for this operation.  if this operation is
899  *    unreliable for a given host, then the host itself needs to put a
900  *    timer on it, and set the host back to a consistent state prior to
901  *    returning.
902  */
903 static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
904 {
905         unsigned long flags;
906         enum scsi_disposition rtn;
907         struct Scsi_Host *host = scmd->device->host;
908         struct scsi_host_template *hostt = host->hostt;
909
910         if (!hostt->eh_target_reset_handler)
911                 return FAILED;
912
913         rtn = hostt->eh_target_reset_handler(scmd);
914         if (rtn == SUCCESS) {
915                 spin_lock_irqsave(host->host_lock, flags);
916                 __starget_for_each_device(scsi_target(scmd->device), NULL,
917                                           __scsi_report_device_reset);
918                 spin_unlock_irqrestore(host->host_lock, flags);
919         }
920
921         return rtn;
922 }
923
924 /**
925  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
926  * @scmd:       SCSI cmd used to send BDR
927  *
928  * Notes:
929  *    There is no timeout for this operation.  if this operation is
930  *    unreliable for a given host, then the host itself needs to put a
931  *    timer on it, and set the host back to a consistent state prior to
932  *    returning.
933  */
934 static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
935 {
936         enum scsi_disposition rtn;
937         struct scsi_host_template *hostt = scmd->device->host->hostt;
938
939         if (!hostt->eh_device_reset_handler)
940                 return FAILED;
941
942         rtn = hostt->eh_device_reset_handler(scmd);
943         if (rtn == SUCCESS)
944                 __scsi_report_device_reset(scmd->device, NULL);
945         return rtn;
946 }
947
948 /**
949  * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
950  * @hostt:      SCSI driver host template
951  * @scmd:       SCSI cmd used to send a target reset
952  *
953  * Return value:
954  *      SUCCESS, FAILED, or FAST_IO_FAIL
955  *
956  * Notes:
957  *    SUCCESS does not necessarily indicate that the command
958  *    has been aborted; it only indicates that the LLDDs
959  *    has cleared all references to that command.
960  *    LLDDs should return FAILED only if an abort was required
961  *    but could not be executed. LLDDs should return FAST_IO_FAIL
962  *    if the device is temporarily unavailable (eg due to a
963  *    link down on FibreChannel)
964  */
965 static enum scsi_disposition
966 scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
967 {
968         if (!hostt->eh_abort_handler)
969                 return FAILED;
970
971         return hostt->eh_abort_handler(scmd);
972 }
973
974 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
975 {
976         if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
977                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
978                         if (scsi_try_target_reset(scmd) != SUCCESS)
979                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
980                                         scsi_try_host_reset(scmd);
981 }
982
983 /**
984  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
985  * @scmd:       SCSI command structure to hijack
986  * @ses:        structure to save restore information
987  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
988  * @cmnd_size:  size in bytes of @cmnd (must be <= MAX_COMMAND_SIZE)
989  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
990  *
991  * This function is used to save a scsi command information before re-execution
992  * as part of the error recovery process.  If @sense_bytes is 0 the command
993  * sent must be one that does not transfer any data.  If @sense_bytes != 0
994  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
995  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
996  */
997 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
998                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
999 {
1000         struct scsi_device *sdev = scmd->device;
1001
1002         /*
1003          * We need saved copies of a number of fields - this is because
1004          * error handling may need to overwrite these with different values
1005          * to run different commands, and once error handling is complete,
1006          * we will need to restore these values prior to running the actual
1007          * command.
1008          */
1009         ses->cmd_len = scmd->cmd_len;
1010         ses->data_direction = scmd->sc_data_direction;
1011         ses->sdb = scmd->sdb;
1012         ses->result = scmd->result;
1013         ses->resid_len = scmd->resid_len;
1014         ses->underflow = scmd->underflow;
1015         ses->prot_op = scmd->prot_op;
1016         ses->eh_eflags = scmd->eh_eflags;
1017
1018         scmd->prot_op = SCSI_PROT_NORMAL;
1019         scmd->eh_eflags = 0;
1020         memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd));
1021         memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
1022         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1023         scmd->result = 0;
1024         scmd->resid_len = 0;
1025
1026         if (sense_bytes) {
1027                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
1028                                          sense_bytes);
1029                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1030                             scmd->sdb.length);
1031                 scmd->sdb.table.sgl = &ses->sense_sgl;
1032                 scmd->sc_data_direction = DMA_FROM_DEVICE;
1033                 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1034                 scmd->cmnd[0] = REQUEST_SENSE;
1035                 scmd->cmnd[4] = scmd->sdb.length;
1036                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1037         } else {
1038                 scmd->sc_data_direction = DMA_NONE;
1039                 if (cmnd) {
1040                         BUG_ON(cmnd_size > sizeof(scmd->cmnd));
1041                         memcpy(scmd->cmnd, cmnd, cmnd_size);
1042                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1043                 }
1044         }
1045
1046         scmd->underflow = 0;
1047
1048         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1049                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1050                         (sdev->lun << 5 & 0xe0);
1051
1052         /*
1053          * Zero the sense buffer.  The scsi spec mandates that any
1054          * untransferred sense data should be interpreted as being zero.
1055          */
1056         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1057 }
1058 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1059
1060 /**
1061  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
1062  * @scmd:       SCSI command structure to restore
1063  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
1064  *
1065  * Undo any damage done by above scsi_eh_prep_cmnd().
1066  */
1067 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1068 {
1069         /*
1070          * Restore original data
1071          */
1072         scmd->cmd_len = ses->cmd_len;
1073         memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd));
1074         scmd->sc_data_direction = ses->data_direction;
1075         scmd->sdb = ses->sdb;
1076         scmd->result = ses->result;
1077         scmd->resid_len = ses->resid_len;
1078         scmd->underflow = ses->underflow;
1079         scmd->prot_op = ses->prot_op;
1080         scmd->eh_eflags = ses->eh_eflags;
1081 }
1082 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1083
1084 /**
1085  * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
1086  * @scmd:       SCSI command structure to hijack
1087  * @cmnd:       CDB to send
1088  * @cmnd_size:  size in bytes of @cmnd
1089  * @timeout:    timeout for this request
1090  * @sense_bytes: size of sense data to copy or 0
1091  *
1092  * This function is used to send a scsi command down to a target device
1093  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1094  *
1095  * Return value:
1096  *    SUCCESS or FAILED or NEEDS_RETRY
1097  */
1098 static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1099         unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1100 {
1101         struct scsi_device *sdev = scmd->device;
1102         struct Scsi_Host *shost = sdev->host;
1103         DECLARE_COMPLETION_ONSTACK(done);
1104         unsigned long timeleft = timeout, delay;
1105         struct scsi_eh_save ses;
1106         const unsigned long stall_for = msecs_to_jiffies(100);
1107         int rtn;
1108
1109 retry:
1110         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1111         shost->eh_action = &done;
1112
1113         scsi_log_send(scmd);
1114         scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
1115
1116         /*
1117          * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1118          * change the SCSI device state after we have examined it and before
1119          * .queuecommand() is called.
1120          */
1121         mutex_lock(&sdev->state_mutex);
1122         while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1123                 mutex_unlock(&sdev->state_mutex);
1124                 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1125                         "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1126                         SDEV_BLOCK));
1127                 delay = min(timeleft, stall_for);
1128                 timeleft -= delay;
1129                 msleep(jiffies_to_msecs(delay));
1130                 mutex_lock(&sdev->state_mutex);
1131         }
1132         if (sdev->sdev_state != SDEV_BLOCK)
1133                 rtn = shost->hostt->queuecommand(shost, scmd);
1134         else
1135                 rtn = FAILED;
1136         mutex_unlock(&sdev->state_mutex);
1137
1138         if (rtn) {
1139                 if (timeleft > stall_for) {
1140                         scsi_eh_restore_cmnd(scmd, &ses);
1141
1142                         timeleft -= stall_for;
1143                         msleep(jiffies_to_msecs(stall_for));
1144                         goto retry;
1145                 }
1146                 /* signal not to enter either branch of the if () below */
1147                 timeleft = 0;
1148                 rtn = FAILED;
1149         } else {
1150                 timeleft = wait_for_completion_timeout(&done, timeout);
1151                 rtn = SUCCESS;
1152         }
1153
1154         shost->eh_action = NULL;
1155
1156         scsi_log_completion(scmd, rtn);
1157
1158         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1159                         "%s timeleft: %ld\n",
1160                         __func__, timeleft));
1161
1162         /*
1163          * If there is time left scsi_eh_done got called, and we will examine
1164          * the actual status codes to see whether the command actually did
1165          * complete normally, else if we have a zero return and no time left,
1166          * the command must still be pending, so abort it and return FAILED.
1167          * If we never actually managed to issue the command, because
1168          * ->queuecommand() kept returning non zero, use the rtn = FAILED
1169          * value above (so don't execute either branch of the if)
1170          */
1171         if (timeleft) {
1172                 rtn = scsi_eh_completed_normally(scmd);
1173                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1174                         "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1175
1176                 switch (rtn) {
1177                 case SUCCESS:
1178                 case NEEDS_RETRY:
1179                 case FAILED:
1180                         break;
1181                 case ADD_TO_MLQUEUE:
1182                         rtn = NEEDS_RETRY;
1183                         break;
1184                 default:
1185                         rtn = FAILED;
1186                         break;
1187                 }
1188         } else if (rtn != FAILED) {
1189                 scsi_abort_eh_cmnd(scmd);
1190                 rtn = FAILED;
1191         }
1192
1193         scsi_eh_restore_cmnd(scmd, &ses);
1194
1195         return rtn;
1196 }
1197
1198 /**
1199  * scsi_request_sense - Request sense data from a particular target.
1200  * @scmd:       SCSI cmd for request sense.
1201  *
1202  * Notes:
1203  *    Some hosts automatically obtain this information, others require
1204  *    that we obtain it on our own. This function will *not* return until
1205  *    the command either times out, or it completes.
1206  */
1207 static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1208 {
1209         return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1210 }
1211
1212 static enum scsi_disposition
1213 scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1214 {
1215         if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
1216                 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1217                 if (sdrv->eh_action)
1218                         rtn = sdrv->eh_action(scmd, rtn);
1219         }
1220         return rtn;
1221 }
1222
1223 /**
1224  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1225  * @scmd:       Original SCSI cmd that eh has finished.
1226  * @done_q:     Queue for processed commands.
1227  *
1228  * Notes:
1229  *    We don't want to use the normal command completion while we are are
1230  *    still handling errors - it may cause other commands to be queued,
1231  *    and that would disturb what we are doing.  Thus we really want to
1232  *    keep a list of pending commands for final completion, and once we
1233  *    are ready to leave error handling we handle completion for real.
1234  */
1235 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1236 {
1237         list_move_tail(&scmd->eh_entry, done_q);
1238 }
1239 EXPORT_SYMBOL(scsi_eh_finish_cmd);
1240
1241 /**
1242  * scsi_eh_get_sense - Get device sense data.
1243  * @work_q:     Queue of commands to process.
1244  * @done_q:     Queue of processed commands.
1245  *
1246  * Description:
1247  *    See if we need to request sense information.  if so, then get it
1248  *    now, so we have a better idea of what to do.
1249  *
1250  * Notes:
1251  *    This has the unfortunate side effect that if a shost adapter does
1252  *    not automatically request sense information, we end up shutting
1253  *    it down before we request it.
1254  *
1255  *    All drivers should request sense information internally these days,
1256  *    so for now all I have to say is tough noogies if you end up in here.
1257  *
1258  *    XXX: Long term this code should go away, but that needs an audit of
1259  *         all LLDDs first.
1260  */
1261 int scsi_eh_get_sense(struct list_head *work_q,
1262                       struct list_head *done_q)
1263 {
1264         struct scsi_cmnd *scmd, *next;
1265         struct Scsi_Host *shost;
1266         enum scsi_disposition rtn;
1267
1268         /*
1269          * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1270          * should not get sense.
1271          */
1272         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1273                 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1274                     SCSI_SENSE_VALID(scmd))
1275                         continue;
1276
1277                 shost = scmd->device->host;
1278                 if (scsi_host_eh_past_deadline(shost)) {
1279                         SCSI_LOG_ERROR_RECOVERY(3,
1280                                 scmd_printk(KERN_INFO, scmd,
1281                                             "%s: skip request sense, past eh deadline\n",
1282                                              current->comm));
1283                         break;
1284                 }
1285                 if (!scsi_status_is_check_condition(scmd->result))
1286                         /*
1287                          * don't request sense if there's no check condition
1288                          * status because the error we're processing isn't one
1289                          * that has a sense code (and some devices get
1290                          * confused by sense requests out of the blue)
1291                          */
1292                         continue;
1293
1294                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1295                                                   "%s: requesting sense\n",
1296                                                   current->comm));
1297                 rtn = scsi_request_sense(scmd);
1298                 if (rtn != SUCCESS)
1299                         continue;
1300
1301                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1302                         "sense requested, result %x\n", scmd->result));
1303                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1304
1305                 rtn = scsi_decide_disposition(scmd);
1306
1307                 /*
1308                  * if the result was normal, then just pass it along to the
1309                  * upper level.
1310                  */
1311                 if (rtn == SUCCESS)
1312                         /*
1313                          * We don't want this command reissued, just finished
1314                          * with the sense data, so set retries to the max
1315                          * allowed to ensure it won't get reissued. If the user
1316                          * has requested infinite retries, we also want to
1317                          * finish this command, so force completion by setting
1318                          * retries and allowed to the same value.
1319                          */
1320                         if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1321                                 scmd->retries = scmd->allowed = 1;
1322                         else
1323                                 scmd->retries = scmd->allowed;
1324                 else if (rtn != NEEDS_RETRY)
1325                         continue;
1326
1327                 scsi_eh_finish_cmd(scmd, done_q);
1328         }
1329
1330         return list_empty(work_q);
1331 }
1332 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1333
1334 /**
1335  * scsi_eh_tur - Send TUR to device.
1336  * @scmd:       &scsi_cmnd to send TUR
1337  *
1338  * Return value:
1339  *    0 - Device is ready. 1 - Device NOT ready.
1340  */
1341 static int scsi_eh_tur(struct scsi_cmnd *scmd)
1342 {
1343         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1344         int retry_cnt = 1;
1345         enum scsi_disposition rtn;
1346
1347 retry_tur:
1348         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1349                                 scmd->device->eh_timeout, 0);
1350
1351         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1352                 "%s return: %x\n", __func__, rtn));
1353
1354         switch (rtn) {
1355         case NEEDS_RETRY:
1356                 if (retry_cnt--)
1357                         goto retry_tur;
1358                 fallthrough;
1359         case SUCCESS:
1360                 return 0;
1361         default:
1362                 return 1;
1363         }
1364 }
1365
1366 /**
1367  * scsi_eh_test_devices - check if devices are responding from error recovery.
1368  * @cmd_list:   scsi commands in error recovery.
1369  * @work_q:     queue for commands which still need more error recovery
1370  * @done_q:     queue for commands which are finished
1371  * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
1372  *
1373  * Decription:
1374  *    Tests if devices are in a working state.  Commands to devices now in
1375  *    a working state are sent to the done_q while commands to devices which
1376  *    are still failing to respond are returned to the work_q for more
1377  *    processing.
1378  **/
1379 static int scsi_eh_test_devices(struct list_head *cmd_list,
1380                                 struct list_head *work_q,
1381                                 struct list_head *done_q, int try_stu)
1382 {
1383         struct scsi_cmnd *scmd, *next;
1384         struct scsi_device *sdev;
1385         int finish_cmds;
1386
1387         while (!list_empty(cmd_list)) {
1388                 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1389                 sdev = scmd->device;
1390
1391                 if (!try_stu) {
1392                         if (scsi_host_eh_past_deadline(sdev->host)) {
1393                                 /* Push items back onto work_q */
1394                                 list_splice_init(cmd_list, work_q);
1395                                 SCSI_LOG_ERROR_RECOVERY(3,
1396                                         sdev_printk(KERN_INFO, sdev,
1397                                                     "%s: skip test device, past eh deadline",
1398                                                     current->comm));
1399                                 break;
1400                         }
1401                 }
1402
1403                 finish_cmds = !scsi_device_online(scmd->device) ||
1404                         (try_stu && !scsi_eh_try_stu(scmd) &&
1405                          !scsi_eh_tur(scmd)) ||
1406                         !scsi_eh_tur(scmd);
1407
1408                 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1409                         if (scmd->device == sdev) {
1410                                 if (finish_cmds &&
1411                                     (try_stu ||
1412                                      scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1413                                         scsi_eh_finish_cmd(scmd, done_q);
1414                                 else
1415                                         list_move_tail(&scmd->eh_entry, work_q);
1416                         }
1417         }
1418         return list_empty(work_q);
1419 }
1420
1421 /**
1422  * scsi_eh_try_stu - Send START_UNIT to device.
1423  * @scmd:       &scsi_cmnd to send START_UNIT
1424  *
1425  * Return value:
1426  *    0 - Device is ready. 1 - Device NOT ready.
1427  */
1428 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1429 {
1430         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1431
1432         if (scmd->device->allow_restart) {
1433                 int i;
1434                 enum scsi_disposition rtn = NEEDS_RETRY;
1435
1436                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1437                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
1438                                                 scmd->device->eh_timeout, 0);
1439
1440                 if (rtn == SUCCESS)
1441                         return 0;
1442         }
1443
1444         return 1;
1445 }
1446
1447  /**
1448  * scsi_eh_stu - send START_UNIT if needed
1449  * @shost:      &scsi host being recovered.
1450  * @work_q:     &list_head for pending commands.
1451  * @done_q:     &list_head for processed commands.
1452  *
1453  * Notes:
1454  *    If commands are failing due to not ready, initializing command required,
1455  *      try revalidating the device, which will end up sending a start unit.
1456  */
1457 static int scsi_eh_stu(struct Scsi_Host *shost,
1458                               struct list_head *work_q,
1459                               struct list_head *done_q)
1460 {
1461         struct scsi_cmnd *scmd, *stu_scmd, *next;
1462         struct scsi_device *sdev;
1463
1464         shost_for_each_device(sdev, shost) {
1465                 if (scsi_host_eh_past_deadline(shost)) {
1466                         SCSI_LOG_ERROR_RECOVERY(3,
1467                                 sdev_printk(KERN_INFO, sdev,
1468                                             "%s: skip START_UNIT, past eh deadline\n",
1469                                             current->comm));
1470                         scsi_device_put(sdev);
1471                         break;
1472                 }
1473                 stu_scmd = NULL;
1474                 list_for_each_entry(scmd, work_q, eh_entry)
1475                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1476                             scsi_check_sense(scmd) == FAILED ) {
1477                                 stu_scmd = scmd;
1478                                 break;
1479                         }
1480
1481                 if (!stu_scmd)
1482                         continue;
1483
1484                 SCSI_LOG_ERROR_RECOVERY(3,
1485                         sdev_printk(KERN_INFO, sdev,
1486                                      "%s: Sending START_UNIT\n",
1487                                     current->comm));
1488
1489                 if (!scsi_eh_try_stu(stu_scmd)) {
1490                         if (!scsi_device_online(sdev) ||
1491                             !scsi_eh_tur(stu_scmd)) {
1492                                 list_for_each_entry_safe(scmd, next,
1493                                                           work_q, eh_entry) {
1494                                         if (scmd->device == sdev &&
1495                                             scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1496                                                 scsi_eh_finish_cmd(scmd, done_q);
1497                                 }
1498                         }
1499                 } else {
1500                         SCSI_LOG_ERROR_RECOVERY(3,
1501                                 sdev_printk(KERN_INFO, sdev,
1502                                             "%s: START_UNIT failed\n",
1503                                             current->comm));
1504                 }
1505         }
1506
1507         return list_empty(work_q);
1508 }
1509
1510
1511 /**
1512  * scsi_eh_bus_device_reset - send bdr if needed
1513  * @shost:      scsi host being recovered.
1514  * @work_q:     &list_head for pending commands.
1515  * @done_q:     &list_head for processed commands.
1516  *
1517  * Notes:
1518  *    Try a bus device reset.  Still, look to see whether we have multiple
1519  *    devices that are jammed or not - if we have multiple devices, it
1520  *    makes no sense to try bus_device_reset - we really would need to try
1521  *    a bus_reset instead.
1522  */
1523 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1524                                     struct list_head *work_q,
1525                                     struct list_head *done_q)
1526 {
1527         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1528         struct scsi_device *sdev;
1529         enum scsi_disposition rtn;
1530
1531         shost_for_each_device(sdev, shost) {
1532                 if (scsi_host_eh_past_deadline(shost)) {
1533                         SCSI_LOG_ERROR_RECOVERY(3,
1534                                 sdev_printk(KERN_INFO, sdev,
1535                                             "%s: skip BDR, past eh deadline\n",
1536                                              current->comm));
1537                         scsi_device_put(sdev);
1538                         break;
1539                 }
1540                 bdr_scmd = NULL;
1541                 list_for_each_entry(scmd, work_q, eh_entry)
1542                         if (scmd->device == sdev) {
1543                                 bdr_scmd = scmd;
1544                                 break;
1545                         }
1546
1547                 if (!bdr_scmd)
1548                         continue;
1549
1550                 SCSI_LOG_ERROR_RECOVERY(3,
1551                         sdev_printk(KERN_INFO, sdev,
1552                                      "%s: Sending BDR\n", current->comm));
1553                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1554                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1555                         if (!scsi_device_online(sdev) ||
1556                             rtn == FAST_IO_FAIL ||
1557                             !scsi_eh_tur(bdr_scmd)) {
1558                                 list_for_each_entry_safe(scmd, next,
1559                                                          work_q, eh_entry) {
1560                                         if (scmd->device == sdev &&
1561                                             scsi_eh_action(scmd, rtn) != FAILED)
1562                                                 scsi_eh_finish_cmd(scmd,
1563                                                                    done_q);
1564                                 }
1565                         }
1566                 } else {
1567                         SCSI_LOG_ERROR_RECOVERY(3,
1568                                 sdev_printk(KERN_INFO, sdev,
1569                                             "%s: BDR failed\n", current->comm));
1570                 }
1571         }
1572
1573         return list_empty(work_q);
1574 }
1575
1576 /**
1577  * scsi_eh_target_reset - send target reset if needed
1578  * @shost:      scsi host being recovered.
1579  * @work_q:     &list_head for pending commands.
1580  * @done_q:     &list_head for processed commands.
1581  *
1582  * Notes:
1583  *    Try a target reset.
1584  */
1585 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1586                                 struct list_head *work_q,
1587                                 struct list_head *done_q)
1588 {
1589         LIST_HEAD(tmp_list);
1590         LIST_HEAD(check_list);
1591
1592         list_splice_init(work_q, &tmp_list);
1593
1594         while (!list_empty(&tmp_list)) {
1595                 struct scsi_cmnd *next, *scmd;
1596                 enum scsi_disposition rtn;
1597                 unsigned int id;
1598
1599                 if (scsi_host_eh_past_deadline(shost)) {
1600                         /* push back on work queue for further processing */
1601                         list_splice_init(&check_list, work_q);
1602                         list_splice_init(&tmp_list, work_q);
1603                         SCSI_LOG_ERROR_RECOVERY(3,
1604                                 shost_printk(KERN_INFO, shost,
1605                                             "%s: Skip target reset, past eh deadline\n",
1606                                              current->comm));
1607                         return list_empty(work_q);
1608                 }
1609
1610                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1611                 id = scmd_id(scmd);
1612
1613                 SCSI_LOG_ERROR_RECOVERY(3,
1614                         shost_printk(KERN_INFO, shost,
1615                                      "%s: Sending target reset to target %d\n",
1616                                      current->comm, id));
1617                 rtn = scsi_try_target_reset(scmd);
1618                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1619                         SCSI_LOG_ERROR_RECOVERY(3,
1620                                 shost_printk(KERN_INFO, shost,
1621                                              "%s: Target reset failed"
1622                                              " target: %d\n",
1623                                              current->comm, id));
1624                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1625                         if (scmd_id(scmd) != id)
1626                                 continue;
1627
1628                         if (rtn == SUCCESS)
1629                                 list_move_tail(&scmd->eh_entry, &check_list);
1630                         else if (rtn == FAST_IO_FAIL)
1631                                 scsi_eh_finish_cmd(scmd, done_q);
1632                         else
1633                                 /* push back on work queue for further processing */
1634                                 list_move(&scmd->eh_entry, work_q);
1635                 }
1636         }
1637
1638         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1639 }
1640
1641 /**
1642  * scsi_eh_bus_reset - send a bus reset
1643  * @shost:      &scsi host being recovered.
1644  * @work_q:     &list_head for pending commands.
1645  * @done_q:     &list_head for processed commands.
1646  */
1647 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1648                              struct list_head *work_q,
1649                              struct list_head *done_q)
1650 {
1651         struct scsi_cmnd *scmd, *chan_scmd, *next;
1652         LIST_HEAD(check_list);
1653         unsigned int channel;
1654         enum scsi_disposition rtn;
1655
1656         /*
1657          * we really want to loop over the various channels, and do this on
1658          * a channel by channel basis.  we should also check to see if any
1659          * of the failed commands are on soft_reset devices, and if so, skip
1660          * the reset.
1661          */
1662
1663         for (channel = 0; channel <= shost->max_channel; channel++) {
1664                 if (scsi_host_eh_past_deadline(shost)) {
1665                         list_splice_init(&check_list, work_q);
1666                         SCSI_LOG_ERROR_RECOVERY(3,
1667                                 shost_printk(KERN_INFO, shost,
1668                                             "%s: skip BRST, past eh deadline\n",
1669                                              current->comm));
1670                         return list_empty(work_q);
1671                 }
1672
1673                 chan_scmd = NULL;
1674                 list_for_each_entry(scmd, work_q, eh_entry) {
1675                         if (channel == scmd_channel(scmd)) {
1676                                 chan_scmd = scmd;
1677                                 break;
1678                                 /*
1679                                  * FIXME add back in some support for
1680                                  * soft_reset devices.
1681                                  */
1682                         }
1683                 }
1684
1685                 if (!chan_scmd)
1686                         continue;
1687                 SCSI_LOG_ERROR_RECOVERY(3,
1688                         shost_printk(KERN_INFO, shost,
1689                                      "%s: Sending BRST chan: %d\n",
1690                                      current->comm, channel));
1691                 rtn = scsi_try_bus_reset(chan_scmd);
1692                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1693                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1694                                 if (channel == scmd_channel(scmd)) {
1695                                         if (rtn == FAST_IO_FAIL)
1696                                                 scsi_eh_finish_cmd(scmd,
1697                                                                    done_q);
1698                                         else
1699                                                 list_move_tail(&scmd->eh_entry,
1700                                                                &check_list);
1701                                 }
1702                         }
1703                 } else {
1704                         SCSI_LOG_ERROR_RECOVERY(3,
1705                                 shost_printk(KERN_INFO, shost,
1706                                              "%s: BRST failed chan: %d\n",
1707                                              current->comm, channel));
1708                 }
1709         }
1710         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1711 }
1712
1713 /**
1714  * scsi_eh_host_reset - send a host reset
1715  * @shost:      host to be reset.
1716  * @work_q:     &list_head for pending commands.
1717  * @done_q:     &list_head for processed commands.
1718  */
1719 static int scsi_eh_host_reset(struct Scsi_Host *shost,
1720                               struct list_head *work_q,
1721                               struct list_head *done_q)
1722 {
1723         struct scsi_cmnd *scmd, *next;
1724         LIST_HEAD(check_list);
1725         enum scsi_disposition rtn;
1726
1727         if (!list_empty(work_q)) {
1728                 scmd = list_entry(work_q->next,
1729                                   struct scsi_cmnd, eh_entry);
1730
1731                 SCSI_LOG_ERROR_RECOVERY(3,
1732                         shost_printk(KERN_INFO, shost,
1733                                      "%s: Sending HRST\n",
1734                                      current->comm));
1735
1736                 rtn = scsi_try_host_reset(scmd);
1737                 if (rtn == SUCCESS) {
1738                         list_splice_init(work_q, &check_list);
1739                 } else if (rtn == FAST_IO_FAIL) {
1740                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1741                                         scsi_eh_finish_cmd(scmd, done_q);
1742                         }
1743                 } else {
1744                         SCSI_LOG_ERROR_RECOVERY(3,
1745                                 shost_printk(KERN_INFO, shost,
1746                                              "%s: HRST failed\n",
1747                                              current->comm));
1748                 }
1749         }
1750         return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1751 }
1752
1753 /**
1754  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1755  * @work_q:     &list_head for pending commands.
1756  * @done_q:     &list_head for processed commands.
1757  */
1758 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1759                                   struct list_head *done_q)
1760 {
1761         struct scsi_cmnd *scmd, *next;
1762         struct scsi_device *sdev;
1763
1764         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1765                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1766                             "not ready after error recovery\n");
1767                 sdev = scmd->device;
1768
1769                 mutex_lock(&sdev->state_mutex);
1770                 scsi_device_set_state(sdev, SDEV_OFFLINE);
1771                 mutex_unlock(&sdev->state_mutex);
1772
1773                 scsi_eh_finish_cmd(scmd, done_q);
1774         }
1775         return;
1776 }
1777
1778 /**
1779  * scsi_noretry_cmd - determine if command should be failed fast
1780  * @scmd:       SCSI cmd to examine.
1781  */
1782 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1783 {
1784         struct request *req = scsi_cmd_to_rq(scmd);
1785
1786         switch (host_byte(scmd->result)) {
1787         case DID_OK:
1788                 break;
1789         case DID_TIME_OUT:
1790                 goto check_type;
1791         case DID_BUS_BUSY:
1792                 return req->cmd_flags & REQ_FAILFAST_TRANSPORT;
1793         case DID_PARITY:
1794                 return req->cmd_flags & REQ_FAILFAST_DEV;
1795         case DID_ERROR:
1796                 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1797                         return 0;
1798                 fallthrough;
1799         case DID_SOFT_ERROR:
1800                 return req->cmd_flags & REQ_FAILFAST_DRIVER;
1801         }
1802
1803         if (!scsi_status_is_check_condition(scmd->result))
1804                 return 0;
1805
1806 check_type:
1807         /*
1808          * assume caller has checked sense and determined
1809          * the check condition was retryable.
1810          */
1811         if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(req))
1812                 return 1;
1813
1814         return 0;
1815 }
1816
1817 /**
1818  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1819  * @scmd:       SCSI cmd to examine.
1820  *
1821  * Notes:
1822  *    This is *only* called when we are examining the status after sending
1823  *    out the actual data command.  any commands that are queued for error
1824  *    recovery (e.g. test_unit_ready) do *not* come through here.
1825  *
1826  *    When this routine returns failed, it means the error handler thread
1827  *    is woken.  In cases where the error code indicates an error that
1828  *    doesn't require the error handler read (i.e. we don't need to
1829  *    abort/reset), this function should return SUCCESS.
1830  */
1831 enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1832 {
1833         enum scsi_disposition rtn;
1834
1835         /*
1836          * if the device is offline, then we clearly just pass the result back
1837          * up to the top level.
1838          */
1839         if (!scsi_device_online(scmd->device)) {
1840                 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1841                         "%s: device offline - report as SUCCESS\n", __func__));
1842                 return SUCCESS;
1843         }
1844
1845         /*
1846          * first check the host byte, to see if there is anything in there
1847          * that would indicate what we need to do.
1848          */
1849         switch (host_byte(scmd->result)) {
1850         case DID_PASSTHROUGH:
1851                 /*
1852                  * no matter what, pass this through to the upper layer.
1853                  * nuke this special code so that it looks like we are saying
1854                  * did_ok.
1855                  */
1856                 scmd->result &= 0xff00ffff;
1857                 return SUCCESS;
1858         case DID_OK:
1859                 /*
1860                  * looks good.  drop through, and check the next byte.
1861                  */
1862                 break;
1863         case DID_ABORT:
1864                 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1865                         set_host_byte(scmd, DID_TIME_OUT);
1866                         return SUCCESS;
1867                 }
1868                 fallthrough;
1869         case DID_NO_CONNECT:
1870         case DID_BAD_TARGET:
1871                 /*
1872                  * note - this means that we just report the status back
1873                  * to the top level driver, not that we actually think
1874                  * that it indicates SUCCESS.
1875                  */
1876                 return SUCCESS;
1877         case DID_SOFT_ERROR:
1878                 /*
1879                  * when the low level driver returns did_soft_error,
1880                  * it is responsible for keeping an internal retry counter
1881                  * in order to avoid endless loops (db)
1882                  */
1883                 goto maybe_retry;
1884         case DID_IMM_RETRY:
1885                 return NEEDS_RETRY;
1886
1887         case DID_REQUEUE:
1888                 return ADD_TO_MLQUEUE;
1889         case DID_TRANSPORT_DISRUPTED:
1890                 /*
1891                  * LLD/transport was disrupted during processing of the IO.
1892                  * The transport class is now blocked/blocking,
1893                  * and the transport will decide what to do with the IO
1894                  * based on its timers and recovery capablilities if
1895                  * there are enough retries.
1896                  */
1897                 goto maybe_retry;
1898         case DID_TRANSPORT_FAILFAST:
1899                 /*
1900                  * The transport decided to failfast the IO (most likely
1901                  * the fast io fail tmo fired), so send IO directly upwards.
1902                  */
1903                 return SUCCESS;
1904         case DID_TRANSPORT_MARGINAL:
1905                 /*
1906                  * caller has decided not to do retries on
1907                  * abort success, so send IO directly upwards
1908                  */
1909                 return SUCCESS;
1910         case DID_ERROR:
1911                 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1912                         /*
1913                          * execute reservation conflict processing code
1914                          * lower down
1915                          */
1916                         break;
1917                 fallthrough;
1918         case DID_BUS_BUSY:
1919         case DID_PARITY:
1920                 goto maybe_retry;
1921         case DID_TIME_OUT:
1922                 /*
1923                  * when we scan the bus, we get timeout messages for
1924                  * these commands if there is no device available.
1925                  * other hosts report did_no_connect for the same thing.
1926                  */
1927                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1928                      scmd->cmnd[0] == INQUIRY)) {
1929                         return SUCCESS;
1930                 } else {
1931                         return FAILED;
1932                 }
1933         case DID_RESET:
1934                 return SUCCESS;
1935         default:
1936                 return FAILED;
1937         }
1938
1939         /*
1940          * check the status byte to see if this indicates anything special.
1941          */
1942         switch (get_status_byte(scmd)) {
1943         case SAM_STAT_TASK_SET_FULL:
1944                 scsi_handle_queue_full(scmd->device);
1945                 /*
1946                  * the case of trying to send too many commands to a
1947                  * tagged queueing device.
1948                  */
1949                 fallthrough;
1950         case SAM_STAT_BUSY:
1951                 /*
1952                  * device can't talk to us at the moment.  Should only
1953                  * occur (SAM-3) when the task queue is empty, so will cause
1954                  * the empty queue handling to trigger a stall in the
1955                  * device.
1956                  */
1957                 return ADD_TO_MLQUEUE;
1958         case SAM_STAT_GOOD:
1959                 if (scmd->cmnd[0] == REPORT_LUNS)
1960                         scmd->device->sdev_target->expecting_lun_change = 0;
1961                 scsi_handle_queue_ramp_up(scmd->device);
1962                 fallthrough;
1963         case SAM_STAT_COMMAND_TERMINATED:
1964                 return SUCCESS;
1965         case SAM_STAT_TASK_ABORTED:
1966                 goto maybe_retry;
1967         case SAM_STAT_CHECK_CONDITION:
1968                 rtn = scsi_check_sense(scmd);
1969                 if (rtn == NEEDS_RETRY)
1970                         goto maybe_retry;
1971                 /* if rtn == FAILED, we have no sense information;
1972                  * returning FAILED will wake the error handler thread
1973                  * to collect the sense and redo the decide
1974                  * disposition */
1975                 return rtn;
1976         case SAM_STAT_CONDITION_MET:
1977         case SAM_STAT_INTERMEDIATE:
1978         case SAM_STAT_INTERMEDIATE_CONDITION_MET:
1979         case SAM_STAT_ACA_ACTIVE:
1980                 /*
1981                  * who knows?  FIXME(eric)
1982                  */
1983                 return SUCCESS;
1984
1985         case SAM_STAT_RESERVATION_CONFLICT:
1986                 sdev_printk(KERN_INFO, scmd->device,
1987                             "reservation conflict\n");
1988                 set_host_byte(scmd, DID_NEXUS_FAILURE);
1989                 return SUCCESS; /* causes immediate i/o error */
1990         }
1991         return FAILED;
1992
1993 maybe_retry:
1994
1995         /* we requeue for retry because the error was retryable, and
1996          * the request was not marked fast fail.  Note that above,
1997          * even if the request is marked fast fail, we still requeue
1998          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1999         if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
2000                 return NEEDS_RETRY;
2001         } else {
2002                 /*
2003                  * no more retries - report this one back to upper level.
2004                  */
2005                 return SUCCESS;
2006         }
2007 }
2008
2009 static void eh_lock_door_done(struct request *req, blk_status_t status)
2010 {
2011         blk_mq_free_request(req);
2012 }
2013
2014 /**
2015  * scsi_eh_lock_door - Prevent medium removal for the specified device
2016  * @sdev:       SCSI device to prevent medium removal
2017  *
2018  * Locking:
2019  *      We must be called from process context.
2020  *
2021  * Notes:
2022  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
2023  *      head of the devices request queue, and continue.
2024  */
2025 static void scsi_eh_lock_door(struct scsi_device *sdev)
2026 {
2027         struct scsi_cmnd *scmd;
2028         struct request *req;
2029
2030         req = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
2031         if (IS_ERR(req))
2032                 return;
2033         scmd = blk_mq_rq_to_pdu(req);
2034
2035         scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL;
2036         scmd->cmnd[1] = 0;
2037         scmd->cmnd[2] = 0;
2038         scmd->cmnd[3] = 0;
2039         scmd->cmnd[4] = SCSI_REMOVAL_PREVENT;
2040         scmd->cmnd[5] = 0;
2041         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
2042         scmd->allowed = 5;
2043
2044         req->rq_flags |= RQF_QUIET;
2045         req->timeout = 10 * HZ;
2046         req->end_io = eh_lock_door_done;
2047
2048         blk_execute_rq_nowait(req, true);
2049 }
2050
2051 /**
2052  * scsi_restart_operations - restart io operations to the specified host.
2053  * @shost:      Host we are restarting.
2054  *
2055  * Notes:
2056  *    When we entered the error handler, we blocked all further i/o to
2057  *    this device.  we need to 'reverse' this process.
2058  */
2059 static void scsi_restart_operations(struct Scsi_Host *shost)
2060 {
2061         struct scsi_device *sdev;
2062         unsigned long flags;
2063
2064         /*
2065          * If the door was locked, we need to insert a door lock request
2066          * onto the head of the SCSI request queue for the device.  There
2067          * is no point trying to lock the door of an off-line device.
2068          */
2069         shost_for_each_device(sdev, shost) {
2070                 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2071                         scsi_eh_lock_door(sdev);
2072                         sdev->was_reset = 0;
2073                 }
2074         }
2075
2076         /*
2077          * next free up anything directly waiting upon the host.  this
2078          * will be requests for character device operations, and also for
2079          * ioctls to queued block devices.
2080          */
2081         SCSI_LOG_ERROR_RECOVERY(3,
2082                 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2083
2084         spin_lock_irqsave(shost->host_lock, flags);
2085         if (scsi_host_set_state(shost, SHOST_RUNNING))
2086                 if (scsi_host_set_state(shost, SHOST_CANCEL))
2087                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2088         spin_unlock_irqrestore(shost->host_lock, flags);
2089
2090         wake_up(&shost->host_wait);
2091
2092         /*
2093          * finally we need to re-initiate requests that may be pending.  we will
2094          * have had everything blocked while error handling is taking place, and
2095          * now that error recovery is done, we will need to ensure that these
2096          * requests are started.
2097          */
2098         scsi_run_host_queues(shost);
2099
2100         /*
2101          * if eh is active and host_eh_scheduled is pending we need to re-run
2102          * recovery.  we do this check after scsi_run_host_queues() to allow
2103          * everything pent up since the last eh run a chance to make forward
2104          * progress before we sync again.  Either we'll immediately re-run
2105          * recovery or scsi_device_unbusy() will wake us again when these
2106          * pending commands complete.
2107          */
2108         spin_lock_irqsave(shost->host_lock, flags);
2109         if (shost->host_eh_scheduled)
2110                 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2111                         WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2112         spin_unlock_irqrestore(shost->host_lock, flags);
2113 }
2114
2115 /**
2116  * scsi_eh_ready_devs - check device ready state and recover if not.
2117  * @shost:      host to be recovered.
2118  * @work_q:     &list_head for pending commands.
2119  * @done_q:     &list_head for processed commands.
2120  */
2121 void scsi_eh_ready_devs(struct Scsi_Host *shost,
2122                         struct list_head *work_q,
2123                         struct list_head *done_q)
2124 {
2125         if (!scsi_eh_stu(shost, work_q, done_q))
2126                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2127                         if (!scsi_eh_target_reset(shost, work_q, done_q))
2128                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2129                                         if (!scsi_eh_host_reset(shost, work_q, done_q))
2130                                                 scsi_eh_offline_sdevs(work_q,
2131                                                                       done_q);
2132 }
2133 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2134
2135 /**
2136  * scsi_eh_flush_done_q - finish processed commands or retry them.
2137  * @done_q:     list_head of processed commands.
2138  */
2139 void scsi_eh_flush_done_q(struct list_head *done_q)
2140 {
2141         struct scsi_cmnd *scmd, *next;
2142
2143         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2144                 list_del_init(&scmd->eh_entry);
2145                 if (scsi_device_online(scmd->device) &&
2146                     !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2147                         scsi_eh_should_retry_cmd(scmd)) {
2148                         SCSI_LOG_ERROR_RECOVERY(3,
2149                                 scmd_printk(KERN_INFO, scmd,
2150                                              "%s: flush retry cmd\n",
2151                                              current->comm));
2152                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2153                 } else {
2154                         /*
2155                          * If just we got sense for the device (called
2156                          * scsi_eh_get_sense), scmd->result is already
2157                          * set, do not set DID_TIME_OUT.
2158                          */
2159                         if (!scmd->result)
2160                                 scmd->result |= (DID_TIME_OUT << 16);
2161                         SCSI_LOG_ERROR_RECOVERY(3,
2162                                 scmd_printk(KERN_INFO, scmd,
2163                                              "%s: flush finish cmd\n",
2164                                              current->comm));
2165                         scsi_finish_command(scmd);
2166                 }
2167         }
2168 }
2169 EXPORT_SYMBOL(scsi_eh_flush_done_q);
2170
2171 /**
2172  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2173  * @shost:      Host to unjam.
2174  *
2175  * Notes:
2176  *    When we come in here, we *know* that all commands on the bus have
2177  *    either completed, failed or timed out.  we also know that no further
2178  *    commands are being sent to the host, so things are relatively quiet
2179  *    and we have freedom to fiddle with things as we wish.
2180  *
2181  *    This is only the *default* implementation.  it is possible for
2182  *    individual drivers to supply their own version of this function, and
2183  *    if the maintainer wishes to do this, it is strongly suggested that
2184  *    this function be taken as a template and modified.  this function
2185  *    was designed to correctly handle problems for about 95% of the
2186  *    different cases out there, and it should always provide at least a
2187  *    reasonable amount of error recovery.
2188  *
2189  *    Any command marked 'failed' or 'timeout' must eventually have
2190  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
2191  *    here, so when we restart the host after we return it should have an
2192  *    empty queue.
2193  */
2194 static void scsi_unjam_host(struct Scsi_Host *shost)
2195 {
2196         unsigned long flags;
2197         LIST_HEAD(eh_work_q);
2198         LIST_HEAD(eh_done_q);
2199
2200         spin_lock_irqsave(shost->host_lock, flags);
2201         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2202         spin_unlock_irqrestore(shost->host_lock, flags);
2203
2204         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2205
2206         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2207                 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2208
2209         spin_lock_irqsave(shost->host_lock, flags);
2210         if (shost->eh_deadline != -1)
2211                 shost->last_reset = 0;
2212         spin_unlock_irqrestore(shost->host_lock, flags);
2213         scsi_eh_flush_done_q(&eh_done_q);
2214 }
2215
2216 /**
2217  * scsi_error_handler - SCSI error handler thread
2218  * @data:       Host for which we are running.
2219  *
2220  * Notes:
2221  *    This is the main error handling loop.  This is run as a kernel thread
2222  *    for every SCSI host and handles all error handling activity.
2223  */
2224 int scsi_error_handler(void *data)
2225 {
2226         struct Scsi_Host *shost = data;
2227
2228         /*
2229          * We use TASK_INTERRUPTIBLE so that the thread is not
2230          * counted against the load average as a running process.
2231          * We never actually get interrupted because kthread_run
2232          * disables signal delivery for the created thread.
2233          */
2234         while (true) {
2235                 /*
2236                  * The sequence in kthread_stop() sets the stop flag first
2237                  * then wakes the process.  To avoid missed wakeups, the task
2238                  * should always be in a non running state before the stop
2239                  * flag is checked
2240                  */
2241                 set_current_state(TASK_INTERRUPTIBLE);
2242                 if (kthread_should_stop())
2243                         break;
2244
2245                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2246                     shost->host_failed != scsi_host_busy(shost)) {
2247                         SCSI_LOG_ERROR_RECOVERY(1,
2248                                 shost_printk(KERN_INFO, shost,
2249                                              "scsi_eh_%d: sleeping\n",
2250                                              shost->host_no));
2251                         schedule();
2252                         continue;
2253                 }
2254
2255                 __set_current_state(TASK_RUNNING);
2256                 SCSI_LOG_ERROR_RECOVERY(1,
2257                         shost_printk(KERN_INFO, shost,
2258                                      "scsi_eh_%d: waking up %d/%d/%d\n",
2259                                      shost->host_no, shost->host_eh_scheduled,
2260                                      shost->host_failed,
2261                                      scsi_host_busy(shost)));
2262
2263                 /*
2264                  * We have a host that is failing for some reason.  Figure out
2265                  * what we need to do to get it up and online again (if we can).
2266                  * If we fail, we end up taking the thing offline.
2267                  */
2268                 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2269                         SCSI_LOG_ERROR_RECOVERY(1,
2270                                 shost_printk(KERN_ERR, shost,
2271                                              "scsi_eh_%d: unable to autoresume\n",
2272                                              shost->host_no));
2273                         continue;
2274                 }
2275
2276                 if (shost->transportt->eh_strategy_handler)
2277                         shost->transportt->eh_strategy_handler(shost);
2278                 else
2279                         scsi_unjam_host(shost);
2280
2281                 /* All scmds have been handled */
2282                 shost->host_failed = 0;
2283
2284                 /*
2285                  * Note - if the above fails completely, the action is to take
2286                  * individual devices offline and flush the queue of any
2287                  * outstanding requests that may have been pending.  When we
2288                  * restart, we restart any I/O to any other devices on the bus
2289                  * which are still online.
2290                  */
2291                 scsi_restart_operations(shost);
2292                 if (!shost->eh_noresume)
2293                         scsi_autopm_put_host(shost);
2294         }
2295         __set_current_state(TASK_RUNNING);
2296
2297         SCSI_LOG_ERROR_RECOVERY(1,
2298                 shost_printk(KERN_INFO, shost,
2299                              "Error handler scsi_eh_%d exiting\n",
2300                              shost->host_no));
2301         shost->ehandler = NULL;
2302         return 0;
2303 }
2304
2305 /*
2306  * Function:    scsi_report_bus_reset()
2307  *
2308  * Purpose:     Utility function used by low-level drivers to report that
2309  *              they have observed a bus reset on the bus being handled.
2310  *
2311  * Arguments:   shost       - Host in question
2312  *              channel     - channel on which reset was observed.
2313  *
2314  * Returns:     Nothing
2315  *
2316  * Lock status: Host lock must be held.
2317  *
2318  * Notes:       This only needs to be called if the reset is one which
2319  *              originates from an unknown location.  Resets originated
2320  *              by the mid-level itself don't need to call this, but there
2321  *              should be no harm.
2322  *
2323  *              The main purpose of this is to make sure that a CHECK_CONDITION
2324  *              is properly treated.
2325  */
2326 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2327 {
2328         struct scsi_device *sdev;
2329
2330         __shost_for_each_device(sdev, shost) {
2331                 if (channel == sdev_channel(sdev))
2332                         __scsi_report_device_reset(sdev, NULL);
2333         }
2334 }
2335 EXPORT_SYMBOL(scsi_report_bus_reset);
2336
2337 /*
2338  * Function:    scsi_report_device_reset()
2339  *
2340  * Purpose:     Utility function used by low-level drivers to report that
2341  *              they have observed a device reset on the device being handled.
2342  *
2343  * Arguments:   shost       - Host in question
2344  *              channel     - channel on which reset was observed
2345  *              target      - target on which reset was observed
2346  *
2347  * Returns:     Nothing
2348  *
2349  * Lock status: Host lock must be held
2350  *
2351  * Notes:       This only needs to be called if the reset is one which
2352  *              originates from an unknown location.  Resets originated
2353  *              by the mid-level itself don't need to call this, but there
2354  *              should be no harm.
2355  *
2356  *              The main purpose of this is to make sure that a CHECK_CONDITION
2357  *              is properly treated.
2358  */
2359 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2360 {
2361         struct scsi_device *sdev;
2362
2363         __shost_for_each_device(sdev, shost) {
2364                 if (channel == sdev_channel(sdev) &&
2365                     target == sdev_id(sdev))
2366                         __scsi_report_device_reset(sdev, NULL);
2367         }
2368 }
2369 EXPORT_SYMBOL(scsi_report_device_reset);
2370
2371 /**
2372  * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2373  * @dev:        scsi_device to operate on
2374  * @arg:        reset type (see sg.h)
2375  */
2376 int
2377 scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2378 {
2379         struct scsi_cmnd *scmd;
2380         struct Scsi_Host *shost = dev->host;
2381         struct request *rq;
2382         unsigned long flags;
2383         int error = 0, val;
2384         enum scsi_disposition rtn;
2385
2386         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2387                 return -EACCES;
2388
2389         error = get_user(val, arg);
2390         if (error)
2391                 return error;
2392
2393         if (scsi_autopm_get_host(shost) < 0)
2394                 return -EIO;
2395
2396         error = -EIO;
2397         rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2398                         shost->hostt->cmd_size, GFP_KERNEL);
2399         if (!rq)
2400                 goto out_put_autopm_host;
2401         blk_rq_init(NULL, rq);
2402
2403         scmd = (struct scsi_cmnd *)(rq + 1);
2404         scsi_init_command(dev, scmd);
2405
2406         scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
2407         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2408
2409         scmd->cmd_len                   = 0;
2410
2411         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
2412
2413         spin_lock_irqsave(shost->host_lock, flags);
2414         shost->tmf_in_progress = 1;
2415         spin_unlock_irqrestore(shost->host_lock, flags);
2416
2417         switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2418         case SG_SCSI_RESET_NOTHING:
2419                 rtn = SUCCESS;
2420                 break;
2421         case SG_SCSI_RESET_DEVICE:
2422                 rtn = scsi_try_bus_device_reset(scmd);
2423                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2424                         break;
2425                 fallthrough;
2426         case SG_SCSI_RESET_TARGET:
2427                 rtn = scsi_try_target_reset(scmd);
2428                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2429                         break;
2430                 fallthrough;
2431         case SG_SCSI_RESET_BUS:
2432                 rtn = scsi_try_bus_reset(scmd);
2433                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2434                         break;
2435                 fallthrough;
2436         case SG_SCSI_RESET_HOST:
2437                 rtn = scsi_try_host_reset(scmd);
2438                 if (rtn == SUCCESS)
2439                         break;
2440                 fallthrough;
2441         default:
2442                 rtn = FAILED;
2443                 break;
2444         }
2445
2446         error = (rtn == SUCCESS) ? 0 : -EIO;
2447
2448         spin_lock_irqsave(shost->host_lock, flags);
2449         shost->tmf_in_progress = 0;
2450         spin_unlock_irqrestore(shost->host_lock, flags);
2451
2452         /*
2453          * be sure to wake up anyone who was sleeping or had their queue
2454          * suspended while we performed the TMF.
2455          */
2456         SCSI_LOG_ERROR_RECOVERY(3,
2457                 shost_printk(KERN_INFO, shost,
2458                              "waking up host to restart after TMF\n"));
2459
2460         wake_up(&shost->host_wait);
2461         scsi_run_host_queues(shost);
2462
2463         kfree(rq);
2464
2465 out_put_autopm_host:
2466         scsi_autopm_put_host(shost);
2467         return error;
2468 }
2469
2470 bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2471                                   struct scsi_sense_hdr *sshdr)
2472 {
2473         return scsi_normalize_sense(cmd->sense_buffer,
2474                         SCSI_SENSE_BUFFERSIZE, sshdr);
2475 }
2476 EXPORT_SYMBOL(scsi_command_normalize_sense);
2477
2478 /**
2479  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2480  * @sense_buffer:       byte array of sense data
2481  * @sb_len:             number of valid bytes in sense_buffer
2482  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2483  *                      field will be placed if found.
2484  *
2485  * Return value:
2486  *      true if information field found, false if not found.
2487  */
2488 bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2489                              u64 *info_out)
2490 {
2491         const u8 * ucp;
2492
2493         if (sb_len < 7)
2494                 return false;
2495         switch (sense_buffer[0] & 0x7f) {
2496         case 0x70:
2497         case 0x71:
2498                 if (sense_buffer[0] & 0x80) {
2499                         *info_out = get_unaligned_be32(&sense_buffer[3]);
2500                         return true;
2501                 }
2502                 return false;
2503         case 0x72:
2504         case 0x73:
2505                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2506                                            0 /* info desc */);
2507                 if (ucp && (0xa == ucp[1])) {
2508                         *info_out = get_unaligned_be64(&ucp[4]);
2509                         return true;
2510                 }
2511                 return false;
2512         default:
2513                 return false;
2514         }
2515 }
2516 EXPORT_SYMBOL(scsi_get_sense_info_fld);