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
60static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
61static enum scsi_disposition scsi_try_to_abort_cmd(const struct scsi_host_template *,
62 struct scsi_cmnd *);
63
64void 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(tsk: 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 */
82void 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(lock: shost->host_lock, flags);
95}
96EXPORT_SYMBOL_GPL(scsi_schedule_eh);
97
98static 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
117static 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
125static 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_timeout(), 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 */
146void
147scmd_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(cmd: scmd, status: 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(entry: &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(head: &shost->eh_abort_list) &&
192 list_empty(head: &shost->eh_cmd_q))
193 if (shost->eh_deadline != -1)
194 shost->last_reset = 0;
195
196 spin_unlock_irqrestore(lock: shost->host_lock, flags);
197
198 if (!scsi_noretry_cmd(scmd) &&
199 scsi_cmd_retry_allowed(cmd: scmd) &&
200 scsi_eh_should_retry_cmd(cmd: scmd)) {
201 SCSI_LOG_ERROR_RECOVERY(3,
202 scmd_printk(KERN_WARNING, scmd,
203 "retry aborted command\n"));
204 scsi_queue_insert(cmd: 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(cmd: scmd);
210 }
211 return;
212
213out:
214 spin_lock_irqsave(shost->host_lock, flags);
215 list_del_init(entry: &scmd->eh_entry);
216 spin_unlock_irqrestore(lock: 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 */
227static int
228scsi_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 (!shost->hostt->eh_abort_handler) {
235 /* No abort handler, fail command directly */
236 return FAILED;
237 }
238
239 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
240 /*
241 * Retry after abort failed, escalate to next level.
242 */
243 SCSI_LOG_ERROR_RECOVERY(3,
244 scmd_printk(KERN_INFO, scmd,
245 "previous abort failed\n"));
246 BUG_ON(delayed_work_pending(&scmd->abort_work));
247 return FAILED;
248 }
249
250 spin_lock_irqsave(shost->host_lock, flags);
251 if (shost->eh_deadline != -1 && !shost->last_reset)
252 shost->last_reset = jiffies;
253 BUG_ON(!list_empty(&scmd->eh_entry));
254 list_add_tail(new: &scmd->eh_entry, head: &shost->eh_abort_list);
255 spin_unlock_irqrestore(lock: shost->host_lock, flags);
256
257 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
258 SCSI_LOG_ERROR_RECOVERY(3,
259 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
260 queue_delayed_work(wq: shost->tmf_work_q, dwork: &scmd->abort_work, HZ / 100);
261 return SUCCESS;
262}
263
264/**
265 * scsi_eh_reset - call into ->eh_action to reset internal counters
266 * @scmd: scmd to run eh on.
267 *
268 * The scsi driver might be carrying internal state about the
269 * devices, so we need to call into the driver to reset the
270 * internal state once the error handler is started.
271 */
272static void scsi_eh_reset(struct scsi_cmnd *scmd)
273{
274 if (!blk_rq_is_passthrough(rq: scsi_cmd_to_rq(scmd))) {
275 struct scsi_driver *sdrv = scsi_cmd_to_driver(cmd: scmd);
276 if (sdrv->eh_reset)
277 sdrv->eh_reset(scmd);
278 }
279}
280
281static void scsi_eh_inc_host_failed(struct rcu_head *head)
282{
283 struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
284 struct Scsi_Host *shost = scmd->device->host;
285 unsigned long flags;
286
287 spin_lock_irqsave(shost->host_lock, flags);
288 shost->host_failed++;
289 scsi_eh_wakeup(shost);
290 spin_unlock_irqrestore(lock: shost->host_lock, flags);
291}
292
293/**
294 * scsi_eh_scmd_add - add scsi cmd to error handling.
295 * @scmd: scmd to run eh on.
296 */
297void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
298{
299 struct Scsi_Host *shost = scmd->device->host;
300 unsigned long flags;
301 int ret;
302
303 WARN_ON_ONCE(!shost->ehandler);
304
305 spin_lock_irqsave(shost->host_lock, flags);
306 if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
307 ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
308 WARN_ON_ONCE(ret);
309 }
310 if (shost->eh_deadline != -1 && !shost->last_reset)
311 shost->last_reset = jiffies;
312
313 scsi_eh_reset(scmd);
314 list_add_tail(new: &scmd->eh_entry, head: &shost->eh_cmd_q);
315 spin_unlock_irqrestore(lock: shost->host_lock, flags);
316 /*
317 * Ensure that all tasks observe the host state change before the
318 * host_failed change.
319 */
320 call_rcu_hurry(head: &scmd->rcu, func: scsi_eh_inc_host_failed);
321}
322
323/**
324 * scsi_timeout - Timeout function for normal scsi commands.
325 * @req: request that is timing out.
326 *
327 * Notes:
328 * We do not need to lock this. There is the potential for a race
329 * only in that the normal completion handling might run, but if the
330 * normal completion function determines that the timer has already
331 * fired, then it mustn't do anything.
332 */
333enum blk_eh_timer_return scsi_timeout(struct request *req)
334{
335 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq: req);
336 struct Scsi_Host *host = scmd->device->host;
337
338 trace_scsi_dispatch_cmd_timeout(cmd: scmd);
339 scsi_log_completion(cmd: scmd, disposition: TIMEOUT_ERROR);
340
341 atomic_inc(v: &scmd->device->iotmo_cnt);
342 if (host->eh_deadline != -1 && !host->last_reset)
343 host->last_reset = jiffies;
344
345 if (host->hostt->eh_timed_out) {
346 switch (host->hostt->eh_timed_out(scmd)) {
347 case SCSI_EH_DONE:
348 return BLK_EH_DONE;
349 case SCSI_EH_RESET_TIMER:
350 return BLK_EH_RESET_TIMER;
351 case SCSI_EH_NOT_HANDLED:
352 break;
353 }
354 }
355
356 /*
357 * If scsi_done() has already set SCMD_STATE_COMPLETE, do not modify
358 * *scmd.
359 */
360 if (test_and_set_bit(SCMD_STATE_COMPLETE, addr: &scmd->state))
361 return BLK_EH_DONE;
362 atomic_inc(v: &scmd->device->iodone_cnt);
363 if (scsi_abort_command(scmd) != SUCCESS) {
364 set_host_byte(cmd: scmd, status: DID_TIME_OUT);
365 scsi_eh_scmd_add(scmd);
366 }
367
368 return BLK_EH_DONE;
369}
370
371/**
372 * scsi_block_when_processing_errors - Prevent cmds from being queued.
373 * @sdev: Device on which we are performing recovery.
374 *
375 * Description:
376 * We block until the host is out of error recovery, and then check to
377 * see whether the host or the device is offline.
378 *
379 * Return value:
380 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
381 */
382int scsi_block_when_processing_errors(struct scsi_device *sdev)
383{
384 int online;
385
386 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
387
388 online = scsi_device_online(sdev);
389
390 return online;
391}
392EXPORT_SYMBOL(scsi_block_when_processing_errors);
393
394#ifdef CONFIG_SCSI_LOGGING
395/**
396 * scsi_eh_prt_fail_stats - Log info on failures.
397 * @shost: scsi host being recovered.
398 * @work_q: Queue of scsi cmds to process.
399 */
400static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
401 struct list_head *work_q)
402{
403 struct scsi_cmnd *scmd;
404 struct scsi_device *sdev;
405 int total_failures = 0;
406 int cmd_failed = 0;
407 int cmd_cancel = 0;
408 int devices_failed = 0;
409
410 shost_for_each_device(sdev, shost) {
411 list_for_each_entry(scmd, work_q, eh_entry) {
412 if (scmd->device == sdev) {
413 ++total_failures;
414 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
415 ++cmd_cancel;
416 else
417 ++cmd_failed;
418 }
419 }
420
421 if (cmd_cancel || cmd_failed) {
422 SCSI_LOG_ERROR_RECOVERY(3,
423 shost_printk(KERN_INFO, shost,
424 "%s: cmds failed: %d, cancel: %d\n",
425 __func__, cmd_failed,
426 cmd_cancel));
427 cmd_cancel = 0;
428 cmd_failed = 0;
429 ++devices_failed;
430 }
431 }
432
433 SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
434 "Total of %d commands on %d"
435 " devices require eh work\n",
436 total_failures, devices_failed));
437}
438#endif
439
440 /**
441 * scsi_report_lun_change - Set flag on all *other* devices on the same target
442 * to indicate that a UNIT ATTENTION is expected.
443 * @sdev: Device reporting the UNIT ATTENTION
444 */
445static void scsi_report_lun_change(struct scsi_device *sdev)
446{
447 sdev->sdev_target->expecting_lun_change = 1;
448}
449
450/**
451 * scsi_report_sense - Examine scsi sense information and log messages for
452 * certain conditions, also issue uevents for some of them.
453 * @sdev: Device reporting the sense code
454 * @sshdr: sshdr to be examined
455 */
456static void scsi_report_sense(struct scsi_device *sdev,
457 struct scsi_sense_hdr *sshdr)
458{
459 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
460
461 if (sshdr->sense_key == UNIT_ATTENTION) {
462 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
463 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
464 sdev_printk(KERN_WARNING, sdev,
465 "Inquiry data has changed");
466 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
467 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
468 scsi_report_lun_change(sdev);
469 sdev_printk(KERN_WARNING, sdev,
470 "LUN assignments on this target have "
471 "changed. The Linux SCSI layer does not "
472 "automatically remap LUN assignments.\n");
473 } else if (sshdr->asc == 0x3f)
474 sdev_printk(KERN_WARNING, sdev,
475 "Operating parameters on this target have "
476 "changed. The Linux SCSI layer does not "
477 "automatically adjust these parameters.\n");
478
479 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
480 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
481 sdev_printk(KERN_WARNING, sdev,
482 "Warning! Received an indication that the "
483 "LUN reached a thin provisioning soft "
484 "threshold.\n");
485 }
486
487 if (sshdr->asc == 0x29) {
488 evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
489 /*
490 * Do not print message if it is an expected side-effect
491 * of runtime PM.
492 */
493 if (!sdev->silence_suspend)
494 sdev_printk(KERN_WARNING, sdev,
495 "Power-on or device reset occurred\n");
496 }
497
498 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
499 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
500 sdev_printk(KERN_WARNING, sdev,
501 "Mode parameters changed");
502 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
503 evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
504 sdev_printk(KERN_WARNING, sdev,
505 "Asymmetric access state changed");
506 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
507 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
508 sdev_printk(KERN_WARNING, sdev,
509 "Capacity data has changed");
510 } else if (sshdr->asc == 0x2a)
511 sdev_printk(KERN_WARNING, sdev,
512 "Parameters changed");
513 }
514
515 if (evt_type != SDEV_EVT_MAXBITS) {
516 set_bit(nr: evt_type, addr: sdev->pending_events);
517 schedule_work(work: &sdev->event_work);
518 }
519}
520
521static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status)
522{
523 cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
524}
525
526/**
527 * scsi_check_sense - Examine scsi cmd sense
528 * @scmd: Cmd to have sense checked.
529 *
530 * Return value:
531 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
532 *
533 * Notes:
534 * When a deferred error is detected the current command has
535 * not been executed and needs retrying.
536 */
537enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
538{
539 struct request *req = scsi_cmd_to_rq(scmd);
540 struct scsi_device *sdev = scmd->device;
541 struct scsi_sense_hdr sshdr;
542
543 if (! scsi_command_normalize_sense(cmd: scmd, sshdr: &sshdr))
544 return FAILED; /* no valid sense data */
545
546 scsi_report_sense(sdev, sshdr: &sshdr);
547
548 if (scsi_sense_is_deferred(sshdr: &sshdr))
549 return NEEDS_RETRY;
550
551 if (sdev->handler && sdev->handler->check_sense) {
552 enum scsi_disposition rc;
553
554 rc = sdev->handler->check_sense(sdev, &sshdr);
555 if (rc != SCSI_RETURN_NOT_HANDLED)
556 return rc;
557 /* handler does not care. Drop down to default handling */
558 }
559
560 if (scmd->cmnd[0] == TEST_UNIT_READY &&
561 scmd->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER)
562 /*
563 * nasty: for mid-layer issued TURs, we need to return the
564 * actual sense data without any recovery attempt. For eh
565 * issued ones, we need to try to recover and interpret
566 */
567 return SUCCESS;
568
569 /*
570 * Previous logic looked for FILEMARK, EOM or ILI which are
571 * mainly associated with tapes and returned SUCCESS.
572 */
573 if (sshdr.response_code == 0x70) {
574 /* fixed format */
575 if (scmd->sense_buffer[2] & 0xe0)
576 return SUCCESS;
577 } else {
578 /*
579 * descriptor format: look for "stream commands sense data
580 * descriptor" (see SSC-3). Assume single sense data
581 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
582 */
583 if ((sshdr.additional_length > 3) &&
584 (scmd->sense_buffer[8] == 0x4) &&
585 (scmd->sense_buffer[11] & 0xe0))
586 return SUCCESS;
587 }
588
589 switch (sshdr.sense_key) {
590 case NO_SENSE:
591 return SUCCESS;
592 case RECOVERED_ERROR:
593 return /* soft_error */ SUCCESS;
594
595 case ABORTED_COMMAND:
596 if (sshdr.asc == 0x10) /* DIF */
597 return SUCCESS;
598
599 /*
600 * Check aborts due to command duration limit policy:
601 * ABORTED COMMAND additional sense code with the
602 * COMMAND TIMEOUT BEFORE PROCESSING or
603 * COMMAND TIMEOUT DURING PROCESSING or
604 * COMMAND TIMEOUT DURING PROCESSING DUE TO ERROR RECOVERY
605 * additional sense code qualifiers.
606 */
607 if (sshdr.asc == 0x2e &&
608 sshdr.ascq >= 0x01 && sshdr.ascq <= 0x03) {
609 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_DL_TIMEOUT);
610 req->cmd_flags |= REQ_FAILFAST_DEV;
611 req->rq_flags |= RQF_QUIET;
612 return SUCCESS;
613 }
614
615 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
616 return ADD_TO_MLQUEUE;
617 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
618 sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
619 return ADD_TO_MLQUEUE;
620
621 return NEEDS_RETRY;
622 case NOT_READY:
623 case UNIT_ATTENTION:
624 /*
625 * if we are expecting a cc/ua because of a bus reset that we
626 * performed, treat this just as a retry. otherwise this is
627 * information that we should pass up to the upper-level driver
628 * so that we can deal with it there.
629 */
630 if (scmd->device->expecting_cc_ua) {
631 /*
632 * Because some device does not queue unit
633 * attentions correctly, we carefully check
634 * additional sense code and qualifier so as
635 * not to squash media change unit attention.
636 */
637 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
638 scmd->device->expecting_cc_ua = 0;
639 return NEEDS_RETRY;
640 }
641 }
642 /*
643 * we might also expect a cc/ua if another LUN on the target
644 * reported a UA with an ASC/ASCQ of 3F 0E -
645 * REPORTED LUNS DATA HAS CHANGED.
646 */
647 if (scmd->device->sdev_target->expecting_lun_change &&
648 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
649 return NEEDS_RETRY;
650 /*
651 * if the device is in the process of becoming ready, we
652 * should retry.
653 */
654 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
655 return NEEDS_RETRY;
656 /*
657 * if the device is not started, we need to wake
658 * the error handler to start the motor
659 */
660 if (scmd->device->allow_restart &&
661 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
662 return FAILED;
663 /*
664 * Pass the UA upwards for a determination in the completion
665 * functions.
666 */
667 return SUCCESS;
668
669 /* these are not supported */
670 case DATA_PROTECT:
671 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
672 /* Thin provisioning hard threshold reached */
673 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_NOSPC);
674 return SUCCESS;
675 }
676 fallthrough;
677 case COPY_ABORTED:
678 case VOLUME_OVERFLOW:
679 case MISCOMPARE:
680 case BLANK_CHECK:
681 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_TGT_FAILURE);
682 return SUCCESS;
683
684 case MEDIUM_ERROR:
685 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
686 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
687 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
688 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_MED_ERROR);
689 return SUCCESS;
690 }
691 return NEEDS_RETRY;
692
693 case HARDWARE_ERROR:
694 if (scmd->device->retry_hwerror)
695 return ADD_TO_MLQUEUE;
696 else
697 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_TGT_FAILURE);
698 fallthrough;
699
700 case ILLEGAL_REQUEST:
701 if (sshdr.asc == 0x20 || /* Invalid command operation code */
702 sshdr.asc == 0x21 || /* Logical block address out of range */
703 sshdr.asc == 0x22 || /* Invalid function */
704 sshdr.asc == 0x24 || /* Invalid field in cdb */
705 sshdr.asc == 0x26 || /* Parameter value invalid */
706 sshdr.asc == 0x27) { /* Write protected */
707 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_TGT_FAILURE);
708 }
709 return SUCCESS;
710
711 case COMPLETED:
712 if (sshdr.asc == 0x55 && sshdr.ascq == 0x0a) {
713 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_DL_TIMEOUT);
714 req->cmd_flags |= REQ_FAILFAST_DEV;
715 req->rq_flags |= RQF_QUIET;
716 }
717 return SUCCESS;
718
719 default:
720 return SUCCESS;
721 }
722}
723EXPORT_SYMBOL_GPL(scsi_check_sense);
724
725static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
726{
727 const struct scsi_host_template *sht = sdev->host->hostt;
728 struct scsi_device *tmp_sdev;
729
730 if (!sht->track_queue_depth ||
731 sdev->queue_depth >= sdev->max_queue_depth)
732 return;
733
734 if (time_before(jiffies,
735 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
736 return;
737
738 if (time_before(jiffies,
739 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
740 return;
741
742 /*
743 * Walk all devices of a target and do
744 * ramp up on them.
745 */
746 shost_for_each_device(tmp_sdev, sdev->host) {
747 if (tmp_sdev->channel != sdev->channel ||
748 tmp_sdev->id != sdev->id ||
749 tmp_sdev->queue_depth == sdev->max_queue_depth)
750 continue;
751
752 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
753 sdev->last_queue_ramp_up = jiffies;
754 }
755}
756
757static void scsi_handle_queue_full(struct scsi_device *sdev)
758{
759 const struct scsi_host_template *sht = sdev->host->hostt;
760 struct scsi_device *tmp_sdev;
761
762 if (!sht->track_queue_depth)
763 return;
764
765 shost_for_each_device(tmp_sdev, sdev->host) {
766 if (tmp_sdev->channel != sdev->channel ||
767 tmp_sdev->id != sdev->id)
768 continue;
769 /*
770 * We do not know the number of commands that were at
771 * the device when we got the queue full so we start
772 * from the highest possible value and work our way down.
773 */
774 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
775 }
776}
777
778/**
779 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
780 * @scmd: SCSI cmd to examine.
781 *
782 * Notes:
783 * This is *only* called when we are examining the status of commands
784 * queued during error recovery. the main difference here is that we
785 * don't allow for the possibility of retries here, and we are a lot
786 * more restrictive about what we consider acceptable.
787 */
788static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
789{
790 /*
791 * first check the host byte, to see if there is anything in there
792 * that would indicate what we need to do.
793 */
794 if (host_byte(scmd->result) == DID_RESET) {
795 /*
796 * rats. we are already in the error handler, so we now
797 * get to try and figure out what to do next. if the sense
798 * is valid, we have a pretty good idea of what to do.
799 * if not, we mark it as FAILED.
800 */
801 return scsi_check_sense(scmd);
802 }
803 if (host_byte(scmd->result) != DID_OK)
804 return FAILED;
805
806 /*
807 * now, check the status byte to see if this indicates
808 * anything special.
809 */
810 switch (get_status_byte(cmd: scmd)) {
811 case SAM_STAT_GOOD:
812 scsi_handle_queue_ramp_up(sdev: scmd->device);
813 if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
814 /*
815 * If we have sense data, call scsi_check_sense() in
816 * order to set the correct SCSI ML byte (if any).
817 * No point in checking the return value, since the
818 * command has already completed successfully.
819 */
820 scsi_check_sense(scmd);
821 fallthrough;
822 case SAM_STAT_COMMAND_TERMINATED:
823 return SUCCESS;
824 case SAM_STAT_CHECK_CONDITION:
825 return scsi_check_sense(scmd);
826 case SAM_STAT_CONDITION_MET:
827 case SAM_STAT_INTERMEDIATE:
828 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
829 /*
830 * who knows? FIXME(eric)
831 */
832 return SUCCESS;
833 case SAM_STAT_RESERVATION_CONFLICT:
834 if (scmd->cmnd[0] == TEST_UNIT_READY)
835 /* it is a success, we probed the device and
836 * found it */
837 return SUCCESS;
838 /* otherwise, we failed to send the command */
839 return FAILED;
840 case SAM_STAT_TASK_SET_FULL:
841 scsi_handle_queue_full(sdev: scmd->device);
842 fallthrough;
843 case SAM_STAT_BUSY:
844 return NEEDS_RETRY;
845 default:
846 return FAILED;
847 }
848 return FAILED;
849}
850
851/**
852 * scsi_eh_done - Completion function for error handling.
853 * @scmd: Cmd that is done.
854 */
855void scsi_eh_done(struct scsi_cmnd *scmd)
856{
857 struct completion *eh_action;
858
859 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
860 "%s result: %x\n", __func__, scmd->result));
861
862 eh_action = scmd->device->host->eh_action;
863 if (eh_action)
864 complete(eh_action);
865}
866
867/**
868 * scsi_try_host_reset - ask host adapter to reset itself
869 * @scmd: SCSI cmd to send host reset.
870 */
871static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
872{
873 unsigned long flags;
874 enum scsi_disposition rtn;
875 struct Scsi_Host *host = scmd->device->host;
876 const struct scsi_host_template *hostt = host->hostt;
877
878 SCSI_LOG_ERROR_RECOVERY(3,
879 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
880
881 if (!hostt->eh_host_reset_handler)
882 return FAILED;
883
884 rtn = hostt->eh_host_reset_handler(scmd);
885
886 if (rtn == SUCCESS) {
887 if (!hostt->skip_settle_delay)
888 ssleep(HOST_RESET_SETTLE_TIME);
889 spin_lock_irqsave(host->host_lock, flags);
890 scsi_report_bus_reset(host, scmd_channel(scmd));
891 spin_unlock_irqrestore(lock: host->host_lock, flags);
892 }
893
894 return rtn;
895}
896
897/**
898 * scsi_try_bus_reset - ask host to perform a bus reset
899 * @scmd: SCSI cmd to send bus reset.
900 */
901static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
902{
903 unsigned long flags;
904 enum scsi_disposition rtn;
905 struct Scsi_Host *host = scmd->device->host;
906 const struct scsi_host_template *hostt = host->hostt;
907
908 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
909 "%s: Snd Bus RST\n", __func__));
910
911 if (!hostt->eh_bus_reset_handler)
912 return FAILED;
913
914 rtn = hostt->eh_bus_reset_handler(scmd);
915
916 if (rtn == SUCCESS) {
917 if (!hostt->skip_settle_delay)
918 ssleep(BUS_RESET_SETTLE_TIME);
919 spin_lock_irqsave(host->host_lock, flags);
920 scsi_report_bus_reset(host, scmd_channel(scmd));
921 spin_unlock_irqrestore(lock: host->host_lock, flags);
922 }
923
924 return rtn;
925}
926
927static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
928{
929 sdev->was_reset = 1;
930 sdev->expecting_cc_ua = 1;
931}
932
933/**
934 * scsi_try_target_reset - Ask host to perform a target reset
935 * @scmd: SCSI cmd used to send a target reset
936 *
937 * Notes:
938 * There is no timeout for this operation. if this operation is
939 * unreliable for a given host, then the host itself needs to put a
940 * timer on it, and set the host back to a consistent state prior to
941 * returning.
942 */
943static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
944{
945 unsigned long flags;
946 enum scsi_disposition rtn;
947 struct Scsi_Host *host = scmd->device->host;
948 const struct scsi_host_template *hostt = host->hostt;
949
950 if (!hostt->eh_target_reset_handler)
951 return FAILED;
952
953 rtn = hostt->eh_target_reset_handler(scmd);
954 if (rtn == SUCCESS) {
955 spin_lock_irqsave(host->host_lock, flags);
956 __starget_for_each_device(scsi_target(sdev: scmd->device), NULL,
957 fn: __scsi_report_device_reset);
958 spin_unlock_irqrestore(lock: host->host_lock, flags);
959 }
960
961 return rtn;
962}
963
964/**
965 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
966 * @scmd: SCSI cmd used to send BDR
967 *
968 * Notes:
969 * There is no timeout for this operation. if this operation is
970 * unreliable for a given host, then the host itself needs to put a
971 * timer on it, and set the host back to a consistent state prior to
972 * returning.
973 */
974static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
975{
976 enum scsi_disposition rtn;
977 const struct scsi_host_template *hostt = scmd->device->host->hostt;
978
979 if (!hostt->eh_device_reset_handler)
980 return FAILED;
981
982 rtn = hostt->eh_device_reset_handler(scmd);
983 if (rtn == SUCCESS)
984 __scsi_report_device_reset(sdev: scmd->device, NULL);
985 return rtn;
986}
987
988/**
989 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
990 * @hostt: SCSI driver host template
991 * @scmd: SCSI cmd used to send a target reset
992 *
993 * Return value:
994 * SUCCESS, FAILED, or FAST_IO_FAIL
995 *
996 * Notes:
997 * SUCCESS does not necessarily indicate that the command
998 * has been aborted; it only indicates that the LLDDs
999 * has cleared all references to that command.
1000 * LLDDs should return FAILED only if an abort was required
1001 * but could not be executed. LLDDs should return FAST_IO_FAIL
1002 * if the device is temporarily unavailable (eg due to a
1003 * link down on FibreChannel)
1004 */
1005static enum scsi_disposition
1006scsi_try_to_abort_cmd(const struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
1007{
1008 if (!hostt->eh_abort_handler)
1009 return FAILED;
1010
1011 return hostt->eh_abort_handler(scmd);
1012}
1013
1014static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
1015{
1016 if (scsi_try_to_abort_cmd(hostt: scmd->device->host->hostt, scmd) != SUCCESS)
1017 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
1018 if (scsi_try_target_reset(scmd) != SUCCESS)
1019 if (scsi_try_bus_reset(scmd) != SUCCESS)
1020 scsi_try_host_reset(scmd);
1021}
1022
1023/**
1024 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
1025 * @scmd: SCSI command structure to hijack
1026 * @ses: structure to save restore information
1027 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
1028 * @cmnd_size: size in bytes of @cmnd (must be <= MAX_COMMAND_SIZE)
1029 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
1030 *
1031 * This function is used to save a scsi command information before re-execution
1032 * as part of the error recovery process. If @sense_bytes is 0 the command
1033 * sent must be one that does not transfer any data. If @sense_bytes != 0
1034 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
1035 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
1036 */
1037void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
1038 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
1039{
1040 struct scsi_device *sdev = scmd->device;
1041
1042 /*
1043 * We need saved copies of a number of fields - this is because
1044 * error handling may need to overwrite these with different values
1045 * to run different commands, and once error handling is complete,
1046 * we will need to restore these values prior to running the actual
1047 * command.
1048 */
1049 ses->cmd_len = scmd->cmd_len;
1050 ses->data_direction = scmd->sc_data_direction;
1051 ses->sdb = scmd->sdb;
1052 ses->result = scmd->result;
1053 ses->resid_len = scmd->resid_len;
1054 ses->underflow = scmd->underflow;
1055 ses->prot_op = scmd->prot_op;
1056 ses->eh_eflags = scmd->eh_eflags;
1057
1058 scmd->prot_op = SCSI_PROT_NORMAL;
1059 scmd->eh_eflags = 0;
1060 memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd));
1061 memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
1062 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1063 scmd->result = 0;
1064 scmd->resid_len = 0;
1065
1066 if (sense_bytes) {
1067 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
1068 sense_bytes);
1069 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1070 scmd->sdb.length);
1071 scmd->sdb.table.sgl = &ses->sense_sgl;
1072 scmd->sc_data_direction = DMA_FROM_DEVICE;
1073 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1074 scmd->cmnd[0] = REQUEST_SENSE;
1075 scmd->cmnd[4] = scmd->sdb.length;
1076 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1077 } else {
1078 scmd->sc_data_direction = DMA_NONE;
1079 if (cmnd) {
1080 BUG_ON(cmnd_size > sizeof(scmd->cmnd));
1081 memcpy(scmd->cmnd, cmnd, cmnd_size);
1082 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1083 }
1084 }
1085
1086 scmd->underflow = 0;
1087
1088 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1089 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1090 (sdev->lun << 5 & 0xe0);
1091
1092 /*
1093 * Zero the sense buffer. The scsi spec mandates that any
1094 * untransferred sense data should be interpreted as being zero.
1095 */
1096 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1097}
1098EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1099
1100/**
1101 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
1102 * @scmd: SCSI command structure to restore
1103 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
1104 *
1105 * Undo any damage done by above scsi_eh_prep_cmnd().
1106 */
1107void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1108{
1109 /*
1110 * Restore original data
1111 */
1112 scmd->cmd_len = ses->cmd_len;
1113 memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd));
1114 scmd->sc_data_direction = ses->data_direction;
1115 scmd->sdb = ses->sdb;
1116 scmd->result = ses->result;
1117 scmd->resid_len = ses->resid_len;
1118 scmd->underflow = ses->underflow;
1119 scmd->prot_op = ses->prot_op;
1120 scmd->eh_eflags = ses->eh_eflags;
1121}
1122EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1123
1124/**
1125 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1126 * @scmd: SCSI command structure to hijack
1127 * @cmnd: CDB to send
1128 * @cmnd_size: size in bytes of @cmnd
1129 * @timeout: timeout for this request
1130 * @sense_bytes: size of sense data to copy or 0
1131 *
1132 * This function is used to send a scsi command down to a target device
1133 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1134 *
1135 * Return value:
1136 * SUCCESS or FAILED or NEEDS_RETRY
1137 */
1138static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1139 unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1140{
1141 struct scsi_device *sdev = scmd->device;
1142 struct Scsi_Host *shost = sdev->host;
1143 DECLARE_COMPLETION_ONSTACK(done);
1144 unsigned long timeleft = timeout, delay;
1145 struct scsi_eh_save ses;
1146 const unsigned long stall_for = msecs_to_jiffies(m: 100);
1147 int rtn;
1148
1149retry:
1150 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1151 shost->eh_action = &done;
1152
1153 scsi_log_send(cmd: scmd);
1154 scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
1155
1156 /*
1157 * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1158 * change the SCSI device state after we have examined it and before
1159 * .queuecommand() is called.
1160 */
1161 mutex_lock(&sdev->state_mutex);
1162 while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1163 mutex_unlock(lock: &sdev->state_mutex);
1164 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1165 "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1166 SDEV_BLOCK));
1167 delay = min(timeleft, stall_for);
1168 timeleft -= delay;
1169 msleep(msecs: jiffies_to_msecs(j: delay));
1170 mutex_lock(&sdev->state_mutex);
1171 }
1172 if (sdev->sdev_state != SDEV_BLOCK)
1173 rtn = shost->hostt->queuecommand(shost, scmd);
1174 else
1175 rtn = FAILED;
1176 mutex_unlock(lock: &sdev->state_mutex);
1177
1178 if (rtn) {
1179 if (timeleft > stall_for) {
1180 scsi_eh_restore_cmnd(scmd, &ses);
1181
1182 timeleft -= stall_for;
1183 msleep(msecs: jiffies_to_msecs(j: stall_for));
1184 goto retry;
1185 }
1186 /* signal not to enter either branch of the if () below */
1187 timeleft = 0;
1188 rtn = FAILED;
1189 } else {
1190 timeleft = wait_for_completion_timeout(x: &done, timeout);
1191 rtn = SUCCESS;
1192 }
1193
1194 shost->eh_action = NULL;
1195
1196 scsi_log_completion(cmd: scmd, disposition: rtn);
1197
1198 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1199 "%s timeleft: %ld\n",
1200 __func__, timeleft));
1201
1202 /*
1203 * If there is time left scsi_eh_done got called, and we will examine
1204 * the actual status codes to see whether the command actually did
1205 * complete normally, else if we have a zero return and no time left,
1206 * the command must still be pending, so abort it and return FAILED.
1207 * If we never actually managed to issue the command, because
1208 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1209 * value above (so don't execute either branch of the if)
1210 */
1211 if (timeleft) {
1212 rtn = scsi_eh_completed_normally(scmd);
1213 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1214 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1215
1216 switch (rtn) {
1217 case SUCCESS:
1218 case NEEDS_RETRY:
1219 case FAILED:
1220 break;
1221 case ADD_TO_MLQUEUE:
1222 rtn = NEEDS_RETRY;
1223 break;
1224 default:
1225 rtn = FAILED;
1226 break;
1227 }
1228 } else if (rtn != FAILED) {
1229 scsi_abort_eh_cmnd(scmd);
1230 rtn = FAILED;
1231 }
1232
1233 scsi_eh_restore_cmnd(scmd, &ses);
1234
1235 return rtn;
1236}
1237
1238/**
1239 * scsi_request_sense - Request sense data from a particular target.
1240 * @scmd: SCSI cmd for request sense.
1241 *
1242 * Notes:
1243 * Some hosts automatically obtain this information, others require
1244 * that we obtain it on our own. This function will *not* return until
1245 * the command either times out, or it completes.
1246 */
1247static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1248{
1249 return scsi_send_eh_cmnd(scmd, NULL, cmnd_size: 0, timeout: scmd->device->eh_timeout, sense_bytes: ~0);
1250}
1251
1252static enum scsi_disposition
1253scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1254{
1255 if (!blk_rq_is_passthrough(rq: scsi_cmd_to_rq(scmd))) {
1256 struct scsi_driver *sdrv = scsi_cmd_to_driver(cmd: scmd);
1257 if (sdrv->eh_action)
1258 rtn = sdrv->eh_action(scmd, rtn);
1259 }
1260 return rtn;
1261}
1262
1263/**
1264 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1265 * @scmd: Original SCSI cmd that eh has finished.
1266 * @done_q: Queue for processed commands.
1267 *
1268 * Notes:
1269 * We don't want to use the normal command completion while we are are
1270 * still handling errors - it may cause other commands to be queued,
1271 * and that would disturb what we are doing. Thus we really want to
1272 * keep a list of pending commands for final completion, and once we
1273 * are ready to leave error handling we handle completion for real.
1274 */
1275void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1276{
1277 list_move_tail(list: &scmd->eh_entry, head: done_q);
1278}
1279EXPORT_SYMBOL(scsi_eh_finish_cmd);
1280
1281/**
1282 * scsi_eh_get_sense - Get device sense data.
1283 * @work_q: Queue of commands to process.
1284 * @done_q: Queue of processed commands.
1285 *
1286 * Description:
1287 * See if we need to request sense information. if so, then get it
1288 * now, so we have a better idea of what to do.
1289 *
1290 * Notes:
1291 * This has the unfortunate side effect that if a shost adapter does
1292 * not automatically request sense information, we end up shutting
1293 * it down before we request it.
1294 *
1295 * All drivers should request sense information internally these days,
1296 * so for now all I have to say is tough noogies if you end up in here.
1297 *
1298 * XXX: Long term this code should go away, but that needs an audit of
1299 * all LLDDs first.
1300 */
1301int scsi_eh_get_sense(struct list_head *work_q,
1302 struct list_head *done_q)
1303{
1304 struct scsi_cmnd *scmd, *next;
1305 struct Scsi_Host *shost;
1306 enum scsi_disposition rtn;
1307
1308 /*
1309 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1310 * should not get sense.
1311 */
1312 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1313 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1314 SCSI_SENSE_VALID(scmd))
1315 continue;
1316
1317 shost = scmd->device->host;
1318 if (scsi_host_eh_past_deadline(shost)) {
1319 SCSI_LOG_ERROR_RECOVERY(3,
1320 scmd_printk(KERN_INFO, scmd,
1321 "%s: skip request sense, past eh deadline\n",
1322 current->comm));
1323 break;
1324 }
1325 if (!scsi_status_is_check_condition(status: scmd->result))
1326 /*
1327 * don't request sense if there's no check condition
1328 * status because the error we're processing isn't one
1329 * that has a sense code (and some devices get
1330 * confused by sense requests out of the blue)
1331 */
1332 continue;
1333
1334 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1335 "%s: requesting sense\n",
1336 current->comm));
1337 rtn = scsi_request_sense(scmd);
1338 if (rtn != SUCCESS)
1339 continue;
1340
1341 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1342 "sense requested, result %x\n", scmd->result));
1343 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1344
1345 rtn = scsi_decide_disposition(cmd: scmd);
1346
1347 /*
1348 * if the result was normal, then just pass it along to the
1349 * upper level.
1350 */
1351 if (rtn == SUCCESS)
1352 /*
1353 * We don't want this command reissued, just finished
1354 * with the sense data, so set retries to the max
1355 * allowed to ensure it won't get reissued. If the user
1356 * has requested infinite retries, we also want to
1357 * finish this command, so force completion by setting
1358 * retries and allowed to the same value.
1359 */
1360 if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1361 scmd->retries = scmd->allowed = 1;
1362 else
1363 scmd->retries = scmd->allowed;
1364 else if (rtn != NEEDS_RETRY)
1365 continue;
1366
1367 scsi_eh_finish_cmd(scmd, done_q);
1368 }
1369
1370 return list_empty(head: work_q);
1371}
1372EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1373
1374/**
1375 * scsi_eh_tur - Send TUR to device.
1376 * @scmd: &scsi_cmnd to send TUR
1377 *
1378 * Return value:
1379 * 0 - Device is ready. 1 - Device NOT ready.
1380 */
1381static int scsi_eh_tur(struct scsi_cmnd *scmd)
1382{
1383 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1384 int retry_cnt = 1;
1385 enum scsi_disposition rtn;
1386
1387retry_tur:
1388 rtn = scsi_send_eh_cmnd(scmd, cmnd: tur_command, cmnd_size: 6,
1389 timeout: scmd->device->eh_timeout, sense_bytes: 0);
1390
1391 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1392 "%s return: %x\n", __func__, rtn));
1393
1394 switch (rtn) {
1395 case NEEDS_RETRY:
1396 if (retry_cnt--)
1397 goto retry_tur;
1398 fallthrough;
1399 case SUCCESS:
1400 return 0;
1401 default:
1402 return 1;
1403 }
1404}
1405
1406/**
1407 * scsi_eh_test_devices - check if devices are responding from error recovery.
1408 * @cmd_list: scsi commands in error recovery.
1409 * @work_q: queue for commands which still need more error recovery
1410 * @done_q: queue for commands which are finished
1411 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1412 *
1413 * Decription:
1414 * Tests if devices are in a working state. Commands to devices now in
1415 * a working state are sent to the done_q while commands to devices which
1416 * are still failing to respond are returned to the work_q for more
1417 * processing.
1418 **/
1419static int scsi_eh_test_devices(struct list_head *cmd_list,
1420 struct list_head *work_q,
1421 struct list_head *done_q, int try_stu)
1422{
1423 struct scsi_cmnd *scmd, *next;
1424 struct scsi_device *sdev;
1425 int finish_cmds;
1426
1427 while (!list_empty(head: cmd_list)) {
1428 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1429 sdev = scmd->device;
1430
1431 if (!try_stu) {
1432 if (scsi_host_eh_past_deadline(shost: sdev->host)) {
1433 /* Push items back onto work_q */
1434 list_splice_init(list: cmd_list, head: work_q);
1435 SCSI_LOG_ERROR_RECOVERY(3,
1436 sdev_printk(KERN_INFO, sdev,
1437 "%s: skip test device, past eh deadline",
1438 current->comm));
1439 break;
1440 }
1441 }
1442
1443 finish_cmds = !scsi_device_online(sdev: scmd->device) ||
1444 (try_stu && !scsi_eh_try_stu(scmd) &&
1445 !scsi_eh_tur(scmd)) ||
1446 !scsi_eh_tur(scmd);
1447
1448 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1449 if (scmd->device == sdev) {
1450 if (finish_cmds &&
1451 (try_stu ||
1452 scsi_eh_action(scmd, rtn: SUCCESS) == SUCCESS))
1453 scsi_eh_finish_cmd(scmd, done_q);
1454 else
1455 list_move_tail(list: &scmd->eh_entry, head: work_q);
1456 }
1457 }
1458 return list_empty(head: work_q);
1459}
1460
1461/**
1462 * scsi_eh_try_stu - Send START_UNIT to device.
1463 * @scmd: &scsi_cmnd to send START_UNIT
1464 *
1465 * Return value:
1466 * 0 - Device is ready. 1 - Device NOT ready.
1467 */
1468static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1469{
1470 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1471
1472 if (scmd->device->allow_restart) {
1473 int i;
1474 enum scsi_disposition rtn = NEEDS_RETRY;
1475
1476 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1477 rtn = scsi_send_eh_cmnd(scmd, cmnd: stu_command, cmnd_size: 6,
1478 timeout: scmd->device->eh_timeout, sense_bytes: 0);
1479
1480 if (rtn == SUCCESS)
1481 return 0;
1482 }
1483
1484 return 1;
1485}
1486
1487 /**
1488 * scsi_eh_stu - send START_UNIT if needed
1489 * @shost: &scsi host being recovered.
1490 * @work_q: &list_head for pending commands.
1491 * @done_q: &list_head for processed commands.
1492 *
1493 * Notes:
1494 * If commands are failing due to not ready, initializing command required,
1495 * try revalidating the device, which will end up sending a start unit.
1496 */
1497static int scsi_eh_stu(struct Scsi_Host *shost,
1498 struct list_head *work_q,
1499 struct list_head *done_q)
1500{
1501 struct scsi_cmnd *scmd, *stu_scmd, *next;
1502 struct scsi_device *sdev;
1503
1504 shost_for_each_device(sdev, shost) {
1505 if (scsi_host_eh_past_deadline(shost)) {
1506 SCSI_LOG_ERROR_RECOVERY(3,
1507 sdev_printk(KERN_INFO, sdev,
1508 "%s: skip START_UNIT, past eh deadline\n",
1509 current->comm));
1510 scsi_device_put(sdev);
1511 break;
1512 }
1513 stu_scmd = NULL;
1514 list_for_each_entry(scmd, work_q, eh_entry)
1515 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1516 scsi_check_sense(scmd) == FAILED ) {
1517 stu_scmd = scmd;
1518 break;
1519 }
1520
1521 if (!stu_scmd)
1522 continue;
1523
1524 SCSI_LOG_ERROR_RECOVERY(3,
1525 sdev_printk(KERN_INFO, sdev,
1526 "%s: Sending START_UNIT\n",
1527 current->comm));
1528
1529 if (!scsi_eh_try_stu(scmd: stu_scmd)) {
1530 if (!scsi_device_online(sdev) ||
1531 !scsi_eh_tur(scmd: stu_scmd)) {
1532 list_for_each_entry_safe(scmd, next,
1533 work_q, eh_entry) {
1534 if (scmd->device == sdev &&
1535 scsi_eh_action(scmd, rtn: SUCCESS) == SUCCESS)
1536 scsi_eh_finish_cmd(scmd, done_q);
1537 }
1538 }
1539 } else {
1540 SCSI_LOG_ERROR_RECOVERY(3,
1541 sdev_printk(KERN_INFO, sdev,
1542 "%s: START_UNIT failed\n",
1543 current->comm));
1544 }
1545 }
1546
1547 return list_empty(head: work_q);
1548}
1549
1550
1551/**
1552 * scsi_eh_bus_device_reset - send bdr if needed
1553 * @shost: scsi host being recovered.
1554 * @work_q: &list_head for pending commands.
1555 * @done_q: &list_head for processed commands.
1556 *
1557 * Notes:
1558 * Try a bus device reset. Still, look to see whether we have multiple
1559 * devices that are jammed or not - if we have multiple devices, it
1560 * makes no sense to try bus_device_reset - we really would need to try
1561 * a bus_reset instead.
1562 */
1563static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1564 struct list_head *work_q,
1565 struct list_head *done_q)
1566{
1567 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1568 struct scsi_device *sdev;
1569 enum scsi_disposition rtn;
1570
1571 shost_for_each_device(sdev, shost) {
1572 if (scsi_host_eh_past_deadline(shost)) {
1573 SCSI_LOG_ERROR_RECOVERY(3,
1574 sdev_printk(KERN_INFO, sdev,
1575 "%s: skip BDR, past eh deadline\n",
1576 current->comm));
1577 scsi_device_put(sdev);
1578 break;
1579 }
1580 bdr_scmd = NULL;
1581 list_for_each_entry(scmd, work_q, eh_entry)
1582 if (scmd->device == sdev) {
1583 bdr_scmd = scmd;
1584 break;
1585 }
1586
1587 if (!bdr_scmd)
1588 continue;
1589
1590 SCSI_LOG_ERROR_RECOVERY(3,
1591 sdev_printk(KERN_INFO, sdev,
1592 "%s: Sending BDR\n", current->comm));
1593 rtn = scsi_try_bus_device_reset(scmd: bdr_scmd);
1594 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1595 if (!scsi_device_online(sdev) ||
1596 rtn == FAST_IO_FAIL ||
1597 !scsi_eh_tur(scmd: bdr_scmd)) {
1598 list_for_each_entry_safe(scmd, next,
1599 work_q, eh_entry) {
1600 if (scmd->device == sdev &&
1601 scsi_eh_action(scmd, rtn) != FAILED)
1602 scsi_eh_finish_cmd(scmd,
1603 done_q);
1604 }
1605 }
1606 } else {
1607 SCSI_LOG_ERROR_RECOVERY(3,
1608 sdev_printk(KERN_INFO, sdev,
1609 "%s: BDR failed\n", current->comm));
1610 }
1611 }
1612
1613 return list_empty(head: work_q);
1614}
1615
1616/**
1617 * scsi_eh_target_reset - send target reset if needed
1618 * @shost: scsi host being recovered.
1619 * @work_q: &list_head for pending commands.
1620 * @done_q: &list_head for processed commands.
1621 *
1622 * Notes:
1623 * Try a target reset.
1624 */
1625static int scsi_eh_target_reset(struct Scsi_Host *shost,
1626 struct list_head *work_q,
1627 struct list_head *done_q)
1628{
1629 LIST_HEAD(tmp_list);
1630 LIST_HEAD(check_list);
1631
1632 list_splice_init(list: work_q, head: &tmp_list);
1633
1634 while (!list_empty(head: &tmp_list)) {
1635 struct scsi_cmnd *next, *scmd;
1636 enum scsi_disposition rtn;
1637 unsigned int id;
1638
1639 if (scsi_host_eh_past_deadline(shost)) {
1640 /* push back on work queue for further processing */
1641 list_splice_init(list: &check_list, head: work_q);
1642 list_splice_init(list: &tmp_list, head: work_q);
1643 SCSI_LOG_ERROR_RECOVERY(3,
1644 shost_printk(KERN_INFO, shost,
1645 "%s: Skip target reset, past eh deadline\n",
1646 current->comm));
1647 return list_empty(head: work_q);
1648 }
1649
1650 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1651 id = scmd_id(scmd);
1652
1653 SCSI_LOG_ERROR_RECOVERY(3,
1654 shost_printk(KERN_INFO, shost,
1655 "%s: Sending target reset to target %d\n",
1656 current->comm, id));
1657 rtn = scsi_try_target_reset(scmd);
1658 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1659 SCSI_LOG_ERROR_RECOVERY(3,
1660 shost_printk(KERN_INFO, shost,
1661 "%s: Target reset failed"
1662 " target: %d\n",
1663 current->comm, id));
1664 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1665 if (scmd_id(scmd) != id)
1666 continue;
1667
1668 if (rtn == SUCCESS)
1669 list_move_tail(list: &scmd->eh_entry, head: &check_list);
1670 else if (rtn == FAST_IO_FAIL)
1671 scsi_eh_finish_cmd(scmd, done_q);
1672 else
1673 /* push back on work queue for further processing */
1674 list_move(list: &scmd->eh_entry, head: work_q);
1675 }
1676 }
1677
1678 return scsi_eh_test_devices(cmd_list: &check_list, work_q, done_q, try_stu: 0);
1679}
1680
1681/**
1682 * scsi_eh_bus_reset - send a bus reset
1683 * @shost: &scsi host being recovered.
1684 * @work_q: &list_head for pending commands.
1685 * @done_q: &list_head for processed commands.
1686 */
1687static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1688 struct list_head *work_q,
1689 struct list_head *done_q)
1690{
1691 struct scsi_cmnd *scmd, *chan_scmd, *next;
1692 LIST_HEAD(check_list);
1693 unsigned int channel;
1694 enum scsi_disposition rtn;
1695
1696 /*
1697 * we really want to loop over the various channels, and do this on
1698 * a channel by channel basis. we should also check to see if any
1699 * of the failed commands are on soft_reset devices, and if so, skip
1700 * the reset.
1701 */
1702
1703 for (channel = 0; channel <= shost->max_channel; channel++) {
1704 if (scsi_host_eh_past_deadline(shost)) {
1705 list_splice_init(list: &check_list, head: work_q);
1706 SCSI_LOG_ERROR_RECOVERY(3,
1707 shost_printk(KERN_INFO, shost,
1708 "%s: skip BRST, past eh deadline\n",
1709 current->comm));
1710 return list_empty(head: work_q);
1711 }
1712
1713 chan_scmd = NULL;
1714 list_for_each_entry(scmd, work_q, eh_entry) {
1715 if (channel == scmd_channel(scmd)) {
1716 chan_scmd = scmd;
1717 break;
1718 /*
1719 * FIXME add back in some support for
1720 * soft_reset devices.
1721 */
1722 }
1723 }
1724
1725 if (!chan_scmd)
1726 continue;
1727 SCSI_LOG_ERROR_RECOVERY(3,
1728 shost_printk(KERN_INFO, shost,
1729 "%s: Sending BRST chan: %d\n",
1730 current->comm, channel));
1731 rtn = scsi_try_bus_reset(scmd: chan_scmd);
1732 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1733 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1734 if (channel == scmd_channel(scmd)) {
1735 if (rtn == FAST_IO_FAIL)
1736 scsi_eh_finish_cmd(scmd,
1737 done_q);
1738 else
1739 list_move_tail(list: &scmd->eh_entry,
1740 head: &check_list);
1741 }
1742 }
1743 } else {
1744 SCSI_LOG_ERROR_RECOVERY(3,
1745 shost_printk(KERN_INFO, shost,
1746 "%s: BRST failed chan: %d\n",
1747 current->comm, channel));
1748 }
1749 }
1750 return scsi_eh_test_devices(cmd_list: &check_list, work_q, done_q, try_stu: 0);
1751}
1752
1753/**
1754 * scsi_eh_host_reset - send a host reset
1755 * @shost: host to be reset.
1756 * @work_q: &list_head for pending commands.
1757 * @done_q: &list_head for processed commands.
1758 */
1759static int scsi_eh_host_reset(struct Scsi_Host *shost,
1760 struct list_head *work_q,
1761 struct list_head *done_q)
1762{
1763 struct scsi_cmnd *scmd, *next;
1764 LIST_HEAD(check_list);
1765 enum scsi_disposition rtn;
1766
1767 if (!list_empty(head: work_q)) {
1768 scmd = list_entry(work_q->next,
1769 struct scsi_cmnd, eh_entry);
1770
1771 SCSI_LOG_ERROR_RECOVERY(3,
1772 shost_printk(KERN_INFO, shost,
1773 "%s: Sending HRST\n",
1774 current->comm));
1775
1776 rtn = scsi_try_host_reset(scmd);
1777 if (rtn == SUCCESS) {
1778 list_splice_init(list: work_q, head: &check_list);
1779 } else if (rtn == FAST_IO_FAIL) {
1780 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1781 scsi_eh_finish_cmd(scmd, done_q);
1782 }
1783 } else {
1784 SCSI_LOG_ERROR_RECOVERY(3,
1785 shost_printk(KERN_INFO, shost,
1786 "%s: HRST failed\n",
1787 current->comm));
1788 }
1789 }
1790 return scsi_eh_test_devices(cmd_list: &check_list, work_q, done_q, try_stu: 1);
1791}
1792
1793/**
1794 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1795 * @work_q: &list_head for pending commands.
1796 * @done_q: &list_head for processed commands.
1797 */
1798static void scsi_eh_offline_sdevs(struct list_head *work_q,
1799 struct list_head *done_q)
1800{
1801 struct scsi_cmnd *scmd, *next;
1802 struct scsi_device *sdev;
1803
1804 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1805 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1806 "not ready after error recovery\n");
1807 sdev = scmd->device;
1808
1809 mutex_lock(&sdev->state_mutex);
1810 scsi_device_set_state(sdev, state: SDEV_OFFLINE);
1811 mutex_unlock(lock: &sdev->state_mutex);
1812
1813 scsi_eh_finish_cmd(scmd, done_q);
1814 }
1815 return;
1816}
1817
1818/**
1819 * scsi_noretry_cmd - determine if command should be failed fast
1820 * @scmd: SCSI cmd to examine.
1821 */
1822bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
1823{
1824 struct request *req = scsi_cmd_to_rq(scmd);
1825
1826 switch (host_byte(scmd->result)) {
1827 case DID_OK:
1828 break;
1829 case DID_TIME_OUT:
1830 goto check_type;
1831 case DID_BUS_BUSY:
1832 return !!(req->cmd_flags & REQ_FAILFAST_TRANSPORT);
1833 case DID_PARITY:
1834 return !!(req->cmd_flags & REQ_FAILFAST_DEV);
1835 case DID_ERROR:
1836 if (get_status_byte(cmd: scmd) == SAM_STAT_RESERVATION_CONFLICT)
1837 return false;
1838 fallthrough;
1839 case DID_SOFT_ERROR:
1840 return !!(req->cmd_flags & REQ_FAILFAST_DRIVER);
1841 }
1842
1843 /* Never retry commands aborted due to a duration limit timeout */
1844 if (scsi_ml_byte(result: scmd->result) == SCSIML_STAT_DL_TIMEOUT)
1845 return true;
1846
1847 if (!scsi_status_is_check_condition(status: scmd->result))
1848 return false;
1849
1850check_type:
1851 /*
1852 * assume caller has checked sense and determined
1853 * the check condition was retryable.
1854 */
1855 if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(rq: req))
1856 return true;
1857
1858 return false;
1859}
1860
1861/**
1862 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1863 * @scmd: SCSI cmd to examine.
1864 *
1865 * Notes:
1866 * This is *only* called when we are examining the status after sending
1867 * out the actual data command. any commands that are queued for error
1868 * recovery (e.g. test_unit_ready) do *not* come through here.
1869 *
1870 * When this routine returns failed, it means the error handler thread
1871 * is woken. In cases where the error code indicates an error that
1872 * doesn't require the error handler read (i.e. we don't need to
1873 * abort/reset), this function should return SUCCESS.
1874 */
1875enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1876{
1877 enum scsi_disposition rtn;
1878
1879 /*
1880 * if the device is offline, then we clearly just pass the result back
1881 * up to the top level.
1882 */
1883 if (!scsi_device_online(sdev: scmd->device)) {
1884 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1885 "%s: device offline - report as SUCCESS\n", __func__));
1886 return SUCCESS;
1887 }
1888
1889 /*
1890 * first check the host byte, to see if there is anything in there
1891 * that would indicate what we need to do.
1892 */
1893 switch (host_byte(scmd->result)) {
1894 case DID_PASSTHROUGH:
1895 /*
1896 * no matter what, pass this through to the upper layer.
1897 * nuke this special code so that it looks like we are saying
1898 * did_ok.
1899 */
1900 scmd->result &= 0xff00ffff;
1901 return SUCCESS;
1902 case DID_OK:
1903 /*
1904 * looks good. drop through, and check the next byte.
1905 */
1906 break;
1907 case DID_ABORT:
1908 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1909 set_host_byte(cmd: scmd, status: DID_TIME_OUT);
1910 return SUCCESS;
1911 }
1912 fallthrough;
1913 case DID_NO_CONNECT:
1914 case DID_BAD_TARGET:
1915 /*
1916 * note - this means that we just report the status back
1917 * to the top level driver, not that we actually think
1918 * that it indicates SUCCESS.
1919 */
1920 return SUCCESS;
1921 case DID_SOFT_ERROR:
1922 /*
1923 * when the low level driver returns did_soft_error,
1924 * it is responsible for keeping an internal retry counter
1925 * in order to avoid endless loops (db)
1926 */
1927 goto maybe_retry;
1928 case DID_IMM_RETRY:
1929 return NEEDS_RETRY;
1930
1931 case DID_REQUEUE:
1932 return ADD_TO_MLQUEUE;
1933 case DID_TRANSPORT_DISRUPTED:
1934 /*
1935 * LLD/transport was disrupted during processing of the IO.
1936 * The transport class is now blocked/blocking,
1937 * and the transport will decide what to do with the IO
1938 * based on its timers and recovery capablilities if
1939 * there are enough retries.
1940 */
1941 goto maybe_retry;
1942 case DID_TRANSPORT_FAILFAST:
1943 /*
1944 * The transport decided to failfast the IO (most likely
1945 * the fast io fail tmo fired), so send IO directly upwards.
1946 */
1947 return SUCCESS;
1948 case DID_TRANSPORT_MARGINAL:
1949 /*
1950 * caller has decided not to do retries on
1951 * abort success, so send IO directly upwards
1952 */
1953 return SUCCESS;
1954 case DID_ERROR:
1955 if (get_status_byte(cmd: scmd) == SAM_STAT_RESERVATION_CONFLICT)
1956 /*
1957 * execute reservation conflict processing code
1958 * lower down
1959 */
1960 break;
1961 fallthrough;
1962 case DID_BUS_BUSY:
1963 case DID_PARITY:
1964 goto maybe_retry;
1965 case DID_TIME_OUT:
1966 /*
1967 * when we scan the bus, we get timeout messages for
1968 * these commands if there is no device available.
1969 * other hosts report did_no_connect for the same thing.
1970 */
1971 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1972 scmd->cmnd[0] == INQUIRY)) {
1973 return SUCCESS;
1974 } else {
1975 return FAILED;
1976 }
1977 case DID_RESET:
1978 return SUCCESS;
1979 default:
1980 return FAILED;
1981 }
1982
1983 /*
1984 * check the status byte to see if this indicates anything special.
1985 */
1986 switch (get_status_byte(cmd: scmd)) {
1987 case SAM_STAT_TASK_SET_FULL:
1988 scsi_handle_queue_full(sdev: scmd->device);
1989 /*
1990 * the case of trying to send too many commands to a
1991 * tagged queueing device.
1992 */
1993 fallthrough;
1994 case SAM_STAT_BUSY:
1995 /*
1996 * device can't talk to us at the moment. Should only
1997 * occur (SAM-3) when the task queue is empty, so will cause
1998 * the empty queue handling to trigger a stall in the
1999 * device.
2000 */
2001 return ADD_TO_MLQUEUE;
2002 case SAM_STAT_GOOD:
2003 if (scmd->cmnd[0] == REPORT_LUNS)
2004 scmd->device->sdev_target->expecting_lun_change = 0;
2005 scsi_handle_queue_ramp_up(sdev: scmd->device);
2006 if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
2007 /*
2008 * If we have sense data, call scsi_check_sense() in
2009 * order to set the correct SCSI ML byte (if any).
2010 * No point in checking the return value, since the
2011 * command has already completed successfully.
2012 */
2013 scsi_check_sense(scmd);
2014 fallthrough;
2015 case SAM_STAT_COMMAND_TERMINATED:
2016 return SUCCESS;
2017 case SAM_STAT_TASK_ABORTED:
2018 goto maybe_retry;
2019 case SAM_STAT_CHECK_CONDITION:
2020 rtn = scsi_check_sense(scmd);
2021 if (rtn == NEEDS_RETRY)
2022 goto maybe_retry;
2023 /* if rtn == FAILED, we have no sense information;
2024 * returning FAILED will wake the error handler thread
2025 * to collect the sense and redo the decide
2026 * disposition */
2027 return rtn;
2028 case SAM_STAT_CONDITION_MET:
2029 case SAM_STAT_INTERMEDIATE:
2030 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
2031 case SAM_STAT_ACA_ACTIVE:
2032 /*
2033 * who knows? FIXME(eric)
2034 */
2035 return SUCCESS;
2036
2037 case SAM_STAT_RESERVATION_CONFLICT:
2038 sdev_printk(KERN_INFO, scmd->device,
2039 "reservation conflict\n");
2040 set_scsi_ml_byte(cmd: scmd, status: SCSIML_STAT_RESV_CONFLICT);
2041 return SUCCESS; /* causes immediate i/o error */
2042 }
2043 return FAILED;
2044
2045maybe_retry:
2046
2047 /* we requeue for retry because the error was retryable, and
2048 * the request was not marked fast fail. Note that above,
2049 * even if the request is marked fast fail, we still requeue
2050 * for queue congestion conditions (QUEUE_FULL or BUSY) */
2051 if (scsi_cmd_retry_allowed(cmd: scmd) && !scsi_noretry_cmd(scmd)) {
2052 return NEEDS_RETRY;
2053 } else {
2054 /*
2055 * no more retries - report this one back to upper level.
2056 */
2057 return SUCCESS;
2058 }
2059}
2060
2061static enum rq_end_io_ret eh_lock_door_done(struct request *req,
2062 blk_status_t status)
2063{
2064 blk_mq_free_request(rq: req);
2065 return RQ_END_IO_NONE;
2066}
2067
2068/**
2069 * scsi_eh_lock_door - Prevent medium removal for the specified device
2070 * @sdev: SCSI device to prevent medium removal
2071 *
2072 * Locking:
2073 * We must be called from process context.
2074 *
2075 * Notes:
2076 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
2077 * head of the devices request queue, and continue.
2078 */
2079static void scsi_eh_lock_door(struct scsi_device *sdev)
2080{
2081 struct scsi_cmnd *scmd;
2082 struct request *req;
2083
2084 req = scsi_alloc_request(q: sdev->request_queue, opf: REQ_OP_DRV_IN, flags: 0);
2085 if (IS_ERR(ptr: req))
2086 return;
2087 scmd = blk_mq_rq_to_pdu(rq: req);
2088
2089 scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL;
2090 scmd->cmnd[1] = 0;
2091 scmd->cmnd[2] = 0;
2092 scmd->cmnd[3] = 0;
2093 scmd->cmnd[4] = SCSI_REMOVAL_PREVENT;
2094 scmd->cmnd[5] = 0;
2095 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
2096 scmd->allowed = 5;
2097
2098 req->rq_flags |= RQF_QUIET;
2099 req->timeout = 10 * HZ;
2100 req->end_io = eh_lock_door_done;
2101
2102 blk_execute_rq_nowait(rq: req, at_head: true);
2103}
2104
2105/**
2106 * scsi_restart_operations - restart io operations to the specified host.
2107 * @shost: Host we are restarting.
2108 *
2109 * Notes:
2110 * When we entered the error handler, we blocked all further i/o to
2111 * this device. we need to 'reverse' this process.
2112 */
2113static void scsi_restart_operations(struct Scsi_Host *shost)
2114{
2115 struct scsi_device *sdev;
2116 unsigned long flags;
2117
2118 /*
2119 * If the door was locked, we need to insert a door lock request
2120 * onto the head of the SCSI request queue for the device. There
2121 * is no point trying to lock the door of an off-line device.
2122 */
2123 shost_for_each_device(sdev, shost) {
2124 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2125 scsi_eh_lock_door(sdev);
2126 sdev->was_reset = 0;
2127 }
2128 }
2129
2130 /*
2131 * next free up anything directly waiting upon the host. this
2132 * will be requests for character device operations, and also for
2133 * ioctls to queued block devices.
2134 */
2135 SCSI_LOG_ERROR_RECOVERY(3,
2136 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2137
2138 spin_lock_irqsave(shost->host_lock, flags);
2139 if (scsi_host_set_state(shost, SHOST_RUNNING))
2140 if (scsi_host_set_state(shost, SHOST_CANCEL))
2141 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2142 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2143
2144 wake_up(&shost->host_wait);
2145
2146 /*
2147 * finally we need to re-initiate requests that may be pending. we will
2148 * have had everything blocked while error handling is taking place, and
2149 * now that error recovery is done, we will need to ensure that these
2150 * requests are started.
2151 */
2152 scsi_run_host_queues(shost);
2153
2154 /*
2155 * if eh is active and host_eh_scheduled is pending we need to re-run
2156 * recovery. we do this check after scsi_run_host_queues() to allow
2157 * everything pent up since the last eh run a chance to make forward
2158 * progress before we sync again. Either we'll immediately re-run
2159 * recovery or scsi_device_unbusy() will wake us again when these
2160 * pending commands complete.
2161 */
2162 spin_lock_irqsave(shost->host_lock, flags);
2163 if (shost->host_eh_scheduled)
2164 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2165 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2166 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2167}
2168
2169/**
2170 * scsi_eh_ready_devs - check device ready state and recover if not.
2171 * @shost: host to be recovered.
2172 * @work_q: &list_head for pending commands.
2173 * @done_q: &list_head for processed commands.
2174 */
2175void scsi_eh_ready_devs(struct Scsi_Host *shost,
2176 struct list_head *work_q,
2177 struct list_head *done_q)
2178{
2179 if (!scsi_eh_stu(shost, work_q, done_q))
2180 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2181 if (!scsi_eh_target_reset(shost, work_q, done_q))
2182 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2183 if (!scsi_eh_host_reset(shost, work_q, done_q))
2184 scsi_eh_offline_sdevs(work_q,
2185 done_q);
2186}
2187EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2188
2189/**
2190 * scsi_eh_flush_done_q - finish processed commands or retry them.
2191 * @done_q: list_head of processed commands.
2192 */
2193void scsi_eh_flush_done_q(struct list_head *done_q)
2194{
2195 struct scsi_cmnd *scmd, *next;
2196
2197 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2198 list_del_init(entry: &scmd->eh_entry);
2199 if (scsi_device_online(sdev: scmd->device) &&
2200 !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(cmd: scmd) &&
2201 scsi_eh_should_retry_cmd(cmd: scmd)) {
2202 SCSI_LOG_ERROR_RECOVERY(3,
2203 scmd_printk(KERN_INFO, scmd,
2204 "%s: flush retry cmd\n",
2205 current->comm));
2206 scsi_queue_insert(cmd: scmd, SCSI_MLQUEUE_EH_RETRY);
2207 } else {
2208 /*
2209 * If just we got sense for the device (called
2210 * scsi_eh_get_sense), scmd->result is already
2211 * set, do not set DID_TIME_OUT.
2212 */
2213 if (!scmd->result &&
2214 !(scmd->flags & SCMD_FORCE_EH_SUCCESS))
2215 scmd->result |= (DID_TIME_OUT << 16);
2216 SCSI_LOG_ERROR_RECOVERY(3,
2217 scmd_printk(KERN_INFO, scmd,
2218 "%s: flush finish cmd\n",
2219 current->comm));
2220 scsi_finish_command(cmd: scmd);
2221 }
2222 }
2223}
2224EXPORT_SYMBOL(scsi_eh_flush_done_q);
2225
2226/**
2227 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2228 * @shost: Host to unjam.
2229 *
2230 * Notes:
2231 * When we come in here, we *know* that all commands on the bus have
2232 * either completed, failed or timed out. we also know that no further
2233 * commands are being sent to the host, so things are relatively quiet
2234 * and we have freedom to fiddle with things as we wish.
2235 *
2236 * This is only the *default* implementation. it is possible for
2237 * individual drivers to supply their own version of this function, and
2238 * if the maintainer wishes to do this, it is strongly suggested that
2239 * this function be taken as a template and modified. this function
2240 * was designed to correctly handle problems for about 95% of the
2241 * different cases out there, and it should always provide at least a
2242 * reasonable amount of error recovery.
2243 *
2244 * Any command marked 'failed' or 'timeout' must eventually have
2245 * scsi_finish_cmd() called for it. we do all of the retry stuff
2246 * here, so when we restart the host after we return it should have an
2247 * empty queue.
2248 */
2249static void scsi_unjam_host(struct Scsi_Host *shost)
2250{
2251 unsigned long flags;
2252 LIST_HEAD(eh_work_q);
2253 LIST_HEAD(eh_done_q);
2254
2255 spin_lock_irqsave(shost->host_lock, flags);
2256 list_splice_init(list: &shost->eh_cmd_q, head: &eh_work_q);
2257 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2258
2259 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2260
2261 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2262 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2263
2264 spin_lock_irqsave(shost->host_lock, flags);
2265 if (shost->eh_deadline != -1)
2266 shost->last_reset = 0;
2267 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2268 scsi_eh_flush_done_q(&eh_done_q);
2269}
2270
2271/**
2272 * scsi_error_handler - SCSI error handler thread
2273 * @data: Host for which we are running.
2274 *
2275 * Notes:
2276 * This is the main error handling loop. This is run as a kernel thread
2277 * for every SCSI host and handles all error handling activity.
2278 */
2279int scsi_error_handler(void *data)
2280{
2281 struct Scsi_Host *shost = data;
2282
2283 /*
2284 * We use TASK_INTERRUPTIBLE so that the thread is not
2285 * counted against the load average as a running process.
2286 * We never actually get interrupted because kthread_run
2287 * disables signal delivery for the created thread.
2288 */
2289 while (true) {
2290 /*
2291 * The sequence in kthread_stop() sets the stop flag first
2292 * then wakes the process. To avoid missed wakeups, the task
2293 * should always be in a non running state before the stop
2294 * flag is checked
2295 */
2296 set_current_state(TASK_INTERRUPTIBLE);
2297 if (kthread_should_stop())
2298 break;
2299
2300 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2301 shost->host_failed != scsi_host_busy(shost)) {
2302 SCSI_LOG_ERROR_RECOVERY(1,
2303 shost_printk(KERN_INFO, shost,
2304 "scsi_eh_%d: sleeping\n",
2305 shost->host_no));
2306 schedule();
2307 continue;
2308 }
2309
2310 __set_current_state(TASK_RUNNING);
2311 SCSI_LOG_ERROR_RECOVERY(1,
2312 shost_printk(KERN_INFO, shost,
2313 "scsi_eh_%d: waking up %d/%d/%d\n",
2314 shost->host_no, shost->host_eh_scheduled,
2315 shost->host_failed,
2316 scsi_host_busy(shost)));
2317
2318 /*
2319 * We have a host that is failing for some reason. Figure out
2320 * what we need to do to get it up and online again (if we can).
2321 * If we fail, we end up taking the thing offline.
2322 */
2323 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2324 SCSI_LOG_ERROR_RECOVERY(1,
2325 shost_printk(KERN_ERR, shost,
2326 "scsi_eh_%d: unable to autoresume\n",
2327 shost->host_no));
2328 continue;
2329 }
2330
2331 if (shost->transportt->eh_strategy_handler)
2332 shost->transportt->eh_strategy_handler(shost);
2333 else
2334 scsi_unjam_host(shost);
2335
2336 /* All scmds have been handled */
2337 shost->host_failed = 0;
2338
2339 /*
2340 * Note - if the above fails completely, the action is to take
2341 * individual devices offline and flush the queue of any
2342 * outstanding requests that may have been pending. When we
2343 * restart, we restart any I/O to any other devices on the bus
2344 * which are still online.
2345 */
2346 scsi_restart_operations(shost);
2347 if (!shost->eh_noresume)
2348 scsi_autopm_put_host(shost);
2349 }
2350 __set_current_state(TASK_RUNNING);
2351
2352 SCSI_LOG_ERROR_RECOVERY(1,
2353 shost_printk(KERN_INFO, shost,
2354 "Error handler scsi_eh_%d exiting\n",
2355 shost->host_no));
2356 shost->ehandler = NULL;
2357 return 0;
2358}
2359
2360/*
2361 * Function: scsi_report_bus_reset()
2362 *
2363 * Purpose: Utility function used by low-level drivers to report that
2364 * they have observed a bus reset on the bus being handled.
2365 *
2366 * Arguments: shost - Host in question
2367 * channel - channel on which reset was observed.
2368 *
2369 * Returns: Nothing
2370 *
2371 * Lock status: Host lock must be held.
2372 *
2373 * Notes: This only needs to be called if the reset is one which
2374 * originates from an unknown location. Resets originated
2375 * by the mid-level itself don't need to call this, but there
2376 * should be no harm.
2377 *
2378 * The main purpose of this is to make sure that a CHECK_CONDITION
2379 * is properly treated.
2380 */
2381void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2382{
2383 struct scsi_device *sdev;
2384
2385 __shost_for_each_device(sdev, shost) {
2386 if (channel == sdev_channel(sdev))
2387 __scsi_report_device_reset(sdev, NULL);
2388 }
2389}
2390EXPORT_SYMBOL(scsi_report_bus_reset);
2391
2392/*
2393 * Function: scsi_report_device_reset()
2394 *
2395 * Purpose: Utility function used by low-level drivers to report that
2396 * they have observed a device reset on the device being handled.
2397 *
2398 * Arguments: shost - Host in question
2399 * channel - channel on which reset was observed
2400 * target - target on which reset was observed
2401 *
2402 * Returns: Nothing
2403 *
2404 * Lock status: Host lock must be held
2405 *
2406 * Notes: This only needs to be called if the reset is one which
2407 * originates from an unknown location. Resets originated
2408 * by the mid-level itself don't need to call this, but there
2409 * should be no harm.
2410 *
2411 * The main purpose of this is to make sure that a CHECK_CONDITION
2412 * is properly treated.
2413 */
2414void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2415{
2416 struct scsi_device *sdev;
2417
2418 __shost_for_each_device(sdev, shost) {
2419 if (channel == sdev_channel(sdev) &&
2420 target == sdev_id(sdev))
2421 __scsi_report_device_reset(sdev, NULL);
2422 }
2423}
2424EXPORT_SYMBOL(scsi_report_device_reset);
2425
2426/**
2427 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2428 * @dev: scsi_device to operate on
2429 * @arg: reset type (see sg.h)
2430 */
2431int
2432scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2433{
2434 struct scsi_cmnd *scmd;
2435 struct Scsi_Host *shost = dev->host;
2436 struct request *rq;
2437 unsigned long flags;
2438 int error = 0, val;
2439 enum scsi_disposition rtn;
2440
2441 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2442 return -EACCES;
2443
2444 error = get_user(val, arg);
2445 if (error)
2446 return error;
2447
2448 if (scsi_autopm_get_host(shost) < 0)
2449 return -EIO;
2450
2451 error = -EIO;
2452 rq = kzalloc(size: sizeof(struct request) + sizeof(struct scsi_cmnd) +
2453 shost->hostt->cmd_size, GFP_KERNEL);
2454 if (!rq)
2455 goto out_put_autopm_host;
2456 blk_rq_init(NULL, rq);
2457
2458 scmd = (struct scsi_cmnd *)(rq + 1);
2459 scsi_init_command(dev, cmd: scmd);
2460
2461 scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
2462 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2463
2464 scmd->cmd_len = 0;
2465
2466 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2467
2468 spin_lock_irqsave(shost->host_lock, flags);
2469 shost->tmf_in_progress = 1;
2470 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2471
2472 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2473 case SG_SCSI_RESET_NOTHING:
2474 rtn = SUCCESS;
2475 break;
2476 case SG_SCSI_RESET_DEVICE:
2477 rtn = scsi_try_bus_device_reset(scmd);
2478 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2479 break;
2480 fallthrough;
2481 case SG_SCSI_RESET_TARGET:
2482 rtn = scsi_try_target_reset(scmd);
2483 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2484 break;
2485 fallthrough;
2486 case SG_SCSI_RESET_BUS:
2487 rtn = scsi_try_bus_reset(scmd);
2488 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2489 break;
2490 fallthrough;
2491 case SG_SCSI_RESET_HOST:
2492 rtn = scsi_try_host_reset(scmd);
2493 if (rtn == SUCCESS)
2494 break;
2495 fallthrough;
2496 default:
2497 rtn = FAILED;
2498 break;
2499 }
2500
2501 error = (rtn == SUCCESS) ? 0 : -EIO;
2502
2503 spin_lock_irqsave(shost->host_lock, flags);
2504 shost->tmf_in_progress = 0;
2505 spin_unlock_irqrestore(lock: shost->host_lock, flags);
2506
2507 /*
2508 * be sure to wake up anyone who was sleeping or had their queue
2509 * suspended while we performed the TMF.
2510 */
2511 SCSI_LOG_ERROR_RECOVERY(3,
2512 shost_printk(KERN_INFO, shost,
2513 "waking up host to restart after TMF\n"));
2514
2515 wake_up(&shost->host_wait);
2516 scsi_run_host_queues(shost);
2517
2518 kfree(objp: rq);
2519
2520out_put_autopm_host:
2521 scsi_autopm_put_host(shost);
2522 return error;
2523}
2524
2525bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2526 struct scsi_sense_hdr *sshdr)
2527{
2528 return scsi_normalize_sense(sense_buffer: cmd->sense_buffer,
2529 SCSI_SENSE_BUFFERSIZE, sshdr);
2530}
2531EXPORT_SYMBOL(scsi_command_normalize_sense);
2532
2533/**
2534 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2535 * @sense_buffer: byte array of sense data
2536 * @sb_len: number of valid bytes in sense_buffer
2537 * @info_out: pointer to 64 integer where 8 or 4 byte information
2538 * field will be placed if found.
2539 *
2540 * Return value:
2541 * true if information field found, false if not found.
2542 */
2543bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2544 u64 *info_out)
2545{
2546 const u8 * ucp;
2547
2548 if (sb_len < 7)
2549 return false;
2550 switch (sense_buffer[0] & 0x7f) {
2551 case 0x70:
2552 case 0x71:
2553 if (sense_buffer[0] & 0x80) {
2554 *info_out = get_unaligned_be32(p: &sense_buffer[3]);
2555 return true;
2556 }
2557 return false;
2558 case 0x72:
2559 case 0x73:
2560 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2561 desc_type: 0 /* info desc */);
2562 if (ucp && (0xa == ucp[1])) {
2563 *info_out = get_unaligned_be64(p: &ucp[4]);
2564 return true;
2565 }
2566 return false;
2567 default:
2568 return false;
2569 }
2570}
2571EXPORT_SYMBOL(scsi_get_sense_info_fld);
2572

source code of linux/drivers/scsi/scsi_error.c