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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
53static void scsi_eh_done(struct scsi_cmnd *scmd);
54
55/*
56 * These should *probably* be handled by the host itself.
57 * Since it is allowed to sleep, it probably should.
58 */
59#define BUS_RESET_SETTLE_TIME (10)
60#define HOST_RESET_SETTLE_TIME (10)
61
62static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
63static enum scsi_disposition scsi_try_to_abort_cmd(struct scsi_host_template *,
64 struct scsi_cmnd *);
65
66void scsi_eh_wakeup(struct Scsi_Host *shost)
67{
68 lockdep_assert_held(shost->host_lock);
69
70 if (scsi_host_busy(shost) == shost->host_failed) {
71 trace_scsi_eh_wakeup(shost);
72 wake_up_process(shost->ehandler);
73 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
74 "Waking error handler thread\n"));
75 }
76}
77
78/**
79 * scsi_schedule_eh - schedule EH for SCSI host
80 * @shost: SCSI host to invoke error handling on.
81 *
82 * Schedule SCSI EH without scmd.
83 */
84void scsi_schedule_eh(struct Scsi_Host *shost)
85{
86 unsigned long flags;
87
88 spin_lock_irqsave(shost->host_lock, flags);
89
90 if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
91 scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
92 shost->host_eh_scheduled++;
93 scsi_eh_wakeup(shost);
94 }
95
96 spin_unlock_irqrestore(shost->host_lock, flags);
97}
98EXPORT_SYMBOL_GPL(scsi_schedule_eh);
99
100static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
101{
102 if (!shost->last_reset || shost->eh_deadline == -1)
103 return 0;
104
105 /*
106 * 32bit accesses are guaranteed to be atomic
107 * (on all supported architectures), so instead
108 * of using a spinlock we can as well double check
109 * if eh_deadline has been set to 'off' during the
110 * time_before call.
111 */
112 if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
113 shost->eh_deadline > -1)
114 return 0;
115
116 return 1;
117}
118
119static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
120{
121 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
122 return true;
123
124 return ++cmd->retries <= cmd->allowed;
125}
126
127static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
128{
129 struct scsi_device *sdev = cmd->device;
130 struct Scsi_Host *host = sdev->host;
131
132 if (host->hostt->eh_should_retry_cmd)
133 return host->hostt->eh_should_retry_cmd(cmd);
134
135 return true;
136}
137
138/**
139 * scmd_eh_abort_handler - Handle command aborts
140 * @work: command to be aborted.
141 *
142 * Note: this function must be called only for a command that has timed out.
143 * Because the block layer marks a request as complete before it calls
144 * scsi_times_out(), a .scsi_done() call from the LLD for a command that has
145 * timed out do not have any effect. Hence it is safe to call
146 * scsi_finish_command() from this function.
147 */
148void
149scmd_eh_abort_handler(struct work_struct *work)
150{
151 struct scsi_cmnd *scmd =
152 container_of(work, struct scsi_cmnd, abort_work.work);
153 struct scsi_device *sdev = scmd->device;
154 enum scsi_disposition rtn;
155
156 if (scsi_host_eh_past_deadline(sdev->host)) {
157 SCSI_LOG_ERROR_RECOVERY(3,
158 scmd_printk(KERN_INFO, scmd,
159 "eh timeout, not aborting\n"));
160 } else {
161 SCSI_LOG_ERROR_RECOVERY(3,
162 scmd_printk(KERN_INFO, scmd,
163 "aborting command\n"));
164 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
165 if (rtn == SUCCESS) {
166 set_host_byte(scmd, DID_TIME_OUT);
167 if (scsi_host_eh_past_deadline(sdev->host)) {
168 SCSI_LOG_ERROR_RECOVERY(3,
169 scmd_printk(KERN_INFO, scmd,
170 "eh timeout, not retrying "
171 "aborted command\n"));
172 } else if (!scsi_noretry_cmd(scmd) &&
173 scsi_cmd_retry_allowed(scmd) &&
174 scsi_eh_should_retry_cmd(scmd)) {
175 SCSI_LOG_ERROR_RECOVERY(3,
176 scmd_printk(KERN_WARNING, scmd,
177 "retry aborted command\n"));
178 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
179 return;
180 } else {
181 SCSI_LOG_ERROR_RECOVERY(3,
182 scmd_printk(KERN_WARNING, scmd,
183 "finish aborted command\n"));
184 scsi_finish_command(scmd);
185 return;
186 }
187 } else {
188 SCSI_LOG_ERROR_RECOVERY(3,
189 scmd_printk(KERN_INFO, scmd,
190 "cmd abort %s\n",
191 (rtn == FAST_IO_FAIL) ?
192 "not send" : "failed"));
193 }
194 }
195
196 scsi_eh_scmd_add(scmd);
197}
198
199/**
200 * scsi_abort_command - schedule a command abort
201 * @scmd: scmd to abort.
202 *
203 * We only need to abort commands after a command timeout
204 */
205static int
206scsi_abort_command(struct scsi_cmnd *scmd)
207{
208 struct scsi_device *sdev = scmd->device;
209 struct Scsi_Host *shost = sdev->host;
210 unsigned long flags;
211
212 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
213 /*
214 * Retry after abort failed, escalate to next level.
215 */
216 SCSI_LOG_ERROR_RECOVERY(3,
217 scmd_printk(KERN_INFO, scmd,
218 "previous abort failed\n"));
219 BUG_ON(delayed_work_pending(&scmd->abort_work));
220 return FAILED;
221 }
222
223 spin_lock_irqsave(shost->host_lock, flags);
224 if (shost->eh_deadline != -1 && !shost->last_reset)
225 shost->last_reset = jiffies;
226 spin_unlock_irqrestore(shost->host_lock, flags);
227
228 scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
229 SCSI_LOG_ERROR_RECOVERY(3,
230 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
231 queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
232 return SUCCESS;
233}
234
235/**
236 * scsi_eh_reset - call into ->eh_action to reset internal counters
237 * @scmd: scmd to run eh on.
238 *
239 * The scsi driver might be carrying internal state about the
240 * devices, so we need to call into the driver to reset the
241 * internal state once the error handler is started.
242 */
243static void scsi_eh_reset(struct scsi_cmnd *scmd)
244{
245 if (!blk_rq_is_passthrough(scmd->request)) {
246 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
247 if (sdrv->eh_reset)
248 sdrv->eh_reset(scmd);
249 }
250}
251
252static void scsi_eh_inc_host_failed(struct rcu_head *head)
253{
254 struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
255 struct Scsi_Host *shost = scmd->device->host;
256 unsigned long flags;
257
258 spin_lock_irqsave(shost->host_lock, flags);
259 shost->host_failed++;
260 scsi_eh_wakeup(shost);
261 spin_unlock_irqrestore(shost->host_lock, flags);
262}
263
264/**
265 * scsi_eh_scmd_add - add scsi cmd to error handling.
266 * @scmd: scmd to run eh on.
267 */
268void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
269{
270 struct Scsi_Host *shost = scmd->device->host;
271 unsigned long flags;
272 int ret;
273
274 WARN_ON_ONCE(!shost->ehandler);
275
276 spin_lock_irqsave(shost->host_lock, flags);
277 if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
278 ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
279 WARN_ON_ONCE(ret);
280 }
281 if (shost->eh_deadline != -1 && !shost->last_reset)
282 shost->last_reset = jiffies;
283
284 scsi_eh_reset(scmd);
285 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
286 spin_unlock_irqrestore(shost->host_lock, flags);
287 /*
288 * Ensure that all tasks observe the host state change before the
289 * host_failed change.
290 */
291 call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
292}
293
294/**
295 * scsi_times_out - Timeout function for normal scsi commands.
296 * @req: request that is timing out.
297 *
298 * Notes:
299 * We do not need to lock this. There is the potential for a race
300 * only in that the normal completion handling might run, but if the
301 * normal completion function determines that the timer has already
302 * fired, then it mustn't do anything.
303 */
304enum blk_eh_timer_return scsi_times_out(struct request *req)
305{
306 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
307 enum blk_eh_timer_return rtn = BLK_EH_DONE;
308 struct Scsi_Host *host = scmd->device->host;
309
310 trace_scsi_dispatch_cmd_timeout(scmd);
311 scsi_log_completion(scmd, TIMEOUT_ERROR);
312
313 if (host->eh_deadline != -1 && !host->last_reset)
314 host->last_reset = jiffies;
315
316 if (host->hostt->eh_timed_out)
317 rtn = host->hostt->eh_timed_out(scmd);
318
319 if (rtn == BLK_EH_DONE) {
320 /*
321 * Set the command to complete first in order to prevent a real
322 * completion from releasing the command while error handling
323 * is using it. If the command was already completed, then the
324 * lower level driver beat the timeout handler, and it is safe
325 * to return without escalating error recovery.
326 *
327 * If timeout handling lost the race to a real completion, the
328 * block layer may ignore that due to a fake timeout injection,
329 * so return RESET_TIMER to allow error handling another shot
330 * at this command.
331 */
332 if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
333 return BLK_EH_RESET_TIMER;
334 if (scsi_abort_command(scmd) != SUCCESS) {
335 set_host_byte(scmd, DID_TIME_OUT);
336 scsi_eh_scmd_add(scmd);
337 }
338 }
339
340 return rtn;
341}
342
343/**
344 * scsi_block_when_processing_errors - Prevent cmds from being queued.
345 * @sdev: Device on which we are performing recovery.
346 *
347 * Description:
348 * We block until the host is out of error recovery, and then check to
349 * see whether the host or the device is offline.
350 *
351 * Return value:
352 * 0 when dev was taken offline by error recovery. 1 OK to proceed.
353 */
354int scsi_block_when_processing_errors(struct scsi_device *sdev)
355{
356 int online;
357
358 wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
359
360 online = scsi_device_online(sdev);
361
362 return online;
363}
364EXPORT_SYMBOL(scsi_block_when_processing_errors);
365
366#ifdef CONFIG_SCSI_LOGGING
367/**
368 * scsi_eh_prt_fail_stats - Log info on failures.
369 * @shost: scsi host being recovered.
370 * @work_q: Queue of scsi cmds to process.
371 */
372static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
373 struct list_head *work_q)
374{
375 struct scsi_cmnd *scmd;
376 struct scsi_device *sdev;
377 int total_failures = 0;
378 int cmd_failed = 0;
379 int cmd_cancel = 0;
380 int devices_failed = 0;
381
382 shost_for_each_device(sdev, shost) {
383 list_for_each_entry(scmd, work_q, eh_entry) {
384 if (scmd->device == sdev) {
385 ++total_failures;
386 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
387 ++cmd_cancel;
388 else
389 ++cmd_failed;
390 }
391 }
392
393 if (cmd_cancel || cmd_failed) {
394 SCSI_LOG_ERROR_RECOVERY(3,
395 shost_printk(KERN_INFO, shost,
396 "%s: cmds failed: %d, cancel: %d\n",
397 __func__, cmd_failed,
398 cmd_cancel));
399 cmd_cancel = 0;
400 cmd_failed = 0;
401 ++devices_failed;
402 }
403 }
404
405 SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
406 "Total of %d commands on %d"
407 " devices require eh work\n",
408 total_failures, devices_failed));
409}
410#endif
411
412 /**
413 * scsi_report_lun_change - Set flag on all *other* devices on the same target
414 * to indicate that a UNIT ATTENTION is expected.
415 * @sdev: Device reporting the UNIT ATTENTION
416 */
417static void scsi_report_lun_change(struct scsi_device *sdev)
418{
419 sdev->sdev_target->expecting_lun_change = 1;
420}
421
422/**
423 * scsi_report_sense - Examine scsi sense information and log messages for
424 * certain conditions, also issue uevents for some of them.
425 * @sdev: Device reporting the sense code
426 * @sshdr: sshdr to be examined
427 */
428static void scsi_report_sense(struct scsi_device *sdev,
429 struct scsi_sense_hdr *sshdr)
430{
431 enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */
432
433 if (sshdr->sense_key == UNIT_ATTENTION) {
434 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
435 evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
436 sdev_printk(KERN_WARNING, sdev,
437 "Inquiry data has changed");
438 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
439 evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
440 scsi_report_lun_change(sdev);
441 sdev_printk(KERN_WARNING, sdev,
442 "Warning! Received an indication that the "
443 "LUN assignments on this target have "
444 "changed. The Linux SCSI layer does not "
445 "automatically remap LUN assignments.\n");
446 } else if (sshdr->asc == 0x3f)
447 sdev_printk(KERN_WARNING, sdev,
448 "Warning! Received an indication that the "
449 "operating parameters on this target have "
450 "changed. The Linux SCSI layer does not "
451 "automatically adjust these parameters.\n");
452
453 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
454 evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
455 sdev_printk(KERN_WARNING, sdev,
456 "Warning! Received an indication that the "
457 "LUN reached a thin provisioning soft "
458 "threshold.\n");
459 }
460
461 if (sshdr->asc == 0x29) {
462 evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
463 sdev_printk(KERN_WARNING, sdev,
464 "Power-on or device reset occurred\n");
465 }
466
467 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
468 evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
469 sdev_printk(KERN_WARNING, sdev,
470 "Mode parameters changed");
471 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
472 evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
473 sdev_printk(KERN_WARNING, sdev,
474 "Asymmetric access state changed");
475 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
476 evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
477 sdev_printk(KERN_WARNING, sdev,
478 "Capacity data has changed");
479 } else if (sshdr->asc == 0x2a)
480 sdev_printk(KERN_WARNING, sdev,
481 "Parameters changed");
482 }
483
484 if (evt_type != SDEV_EVT_MAXBITS) {
485 set_bit(evt_type, sdev->pending_events);
486 schedule_work(&sdev->event_work);
487 }
488}
489
490/**
491 * scsi_check_sense - Examine scsi cmd sense
492 * @scmd: Cmd to have sense checked.
493 *
494 * Return value:
495 * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
496 *
497 * Notes:
498 * When a deferred error is detected the current command has
499 * not been executed and needs retrying.
500 */
501enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
502{
503 struct scsi_device *sdev = scmd->device;
504 struct scsi_sense_hdr sshdr;
505
506 if (! scsi_command_normalize_sense(scmd, &sshdr))
507 return FAILED; /* no valid sense data */
508
509 scsi_report_sense(sdev, &sshdr);
510
511 if (scsi_sense_is_deferred(&sshdr))
512 return NEEDS_RETRY;
513
514 if (sdev->handler && sdev->handler->check_sense) {
515 enum scsi_disposition rc;
516
517 rc = sdev->handler->check_sense(sdev, &sshdr);
518 if (rc != SCSI_RETURN_NOT_HANDLED)
519 return rc;
520 /* handler does not care. Drop down to default handling */
521 }
522
523 if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
524 /*
525 * nasty: for mid-layer issued TURs, we need to return the
526 * actual sense data without any recovery attempt. For eh
527 * issued ones, we need to try to recover and interpret
528 */
529 return SUCCESS;
530
531 /*
532 * Previous logic looked for FILEMARK, EOM or ILI which are
533 * mainly associated with tapes and returned SUCCESS.
534 */
535 if (sshdr.response_code == 0x70) {
536 /* fixed format */
537 if (scmd->sense_buffer[2] & 0xe0)
538 return SUCCESS;
539 } else {
540 /*
541 * descriptor format: look for "stream commands sense data
542 * descriptor" (see SSC-3). Assume single sense data
543 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
544 */
545 if ((sshdr.additional_length > 3) &&
546 (scmd->sense_buffer[8] == 0x4) &&
547 (scmd->sense_buffer[11] & 0xe0))
548 return SUCCESS;
549 }
550
551 switch (sshdr.sense_key) {
552 case NO_SENSE:
553 return SUCCESS;
554 case RECOVERED_ERROR:
555 return /* soft_error */ SUCCESS;
556
557 case ABORTED_COMMAND:
558 if (sshdr.asc == 0x10) /* DIF */
559 return SUCCESS;
560
561 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
562 return ADD_TO_MLQUEUE;
563 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
564 sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
565 return ADD_TO_MLQUEUE;
566
567 return NEEDS_RETRY;
568 case NOT_READY:
569 case UNIT_ATTENTION:
570 /*
571 * if we are expecting a cc/ua because of a bus reset that we
572 * performed, treat this just as a retry. otherwise this is
573 * information that we should pass up to the upper-level driver
574 * so that we can deal with it there.
575 */
576 if (scmd->device->expecting_cc_ua) {
577 /*
578 * Because some device does not queue unit
579 * attentions correctly, we carefully check
580 * additional sense code and qualifier so as
581 * not to squash media change unit attention.
582 */
583 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
584 scmd->device->expecting_cc_ua = 0;
585 return NEEDS_RETRY;
586 }
587 }
588 /*
589 * we might also expect a cc/ua if another LUN on the target
590 * reported a UA with an ASC/ASCQ of 3F 0E -
591 * REPORTED LUNS DATA HAS CHANGED.
592 */
593 if (scmd->device->sdev_target->expecting_lun_change &&
594 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
595 return NEEDS_RETRY;
596 /*
597 * if the device is in the process of becoming ready, we
598 * should retry.
599 */
600 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
601 return NEEDS_RETRY;
602 /*
603 * if the device is not started, we need to wake
604 * the error handler to start the motor
605 */
606 if (scmd->device->allow_restart &&
607 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
608 return FAILED;
609 /*
610 * Pass the UA upwards for a determination in the completion
611 * functions.
612 */
613 return SUCCESS;
614
615 /* these are not supported */
616 case DATA_PROTECT:
617 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
618 /* Thin provisioning hard threshold reached */
619 set_host_byte(scmd, DID_ALLOC_FAILURE);
620 return SUCCESS;
621 }
622 fallthrough;
623 case COPY_ABORTED:
624 case VOLUME_OVERFLOW:
625 case MISCOMPARE:
626 case BLANK_CHECK:
627 set_host_byte(scmd, DID_TARGET_FAILURE);
628 return SUCCESS;
629
630 case MEDIUM_ERROR:
631 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
632 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
633 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
634 set_host_byte(scmd, DID_MEDIUM_ERROR);
635 return SUCCESS;
636 }
637 return NEEDS_RETRY;
638
639 case HARDWARE_ERROR:
640 if (scmd->device->retry_hwerror)
641 return ADD_TO_MLQUEUE;
642 else
643 set_host_byte(scmd, DID_TARGET_FAILURE);
644 fallthrough;
645
646 case ILLEGAL_REQUEST:
647 if (sshdr.asc == 0x20 || /* Invalid command operation code */
648 sshdr.asc == 0x21 || /* Logical block address out of range */
649 sshdr.asc == 0x22 || /* Invalid function */
650 sshdr.asc == 0x24 || /* Invalid field in cdb */
651 sshdr.asc == 0x26 || /* Parameter value invalid */
652 sshdr.asc == 0x27) { /* Write protected */
653 set_host_byte(scmd, DID_TARGET_FAILURE);
654 }
655 return SUCCESS;
656
657 default:
658 return SUCCESS;
659 }
660}
661EXPORT_SYMBOL_GPL(scsi_check_sense);
662
663static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
664{
665 struct scsi_host_template *sht = sdev->host->hostt;
666 struct scsi_device *tmp_sdev;
667
668 if (!sht->track_queue_depth ||
669 sdev->queue_depth >= sdev->max_queue_depth)
670 return;
671
672 if (time_before(jiffies,
673 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
674 return;
675
676 if (time_before(jiffies,
677 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
678 return;
679
680 /*
681 * Walk all devices of a target and do
682 * ramp up on them.
683 */
684 shost_for_each_device(tmp_sdev, sdev->host) {
685 if (tmp_sdev->channel != sdev->channel ||
686 tmp_sdev->id != sdev->id ||
687 tmp_sdev->queue_depth == sdev->max_queue_depth)
688 continue;
689
690 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
691 sdev->last_queue_ramp_up = jiffies;
692 }
693}
694
695static void scsi_handle_queue_full(struct scsi_device *sdev)
696{
697 struct scsi_host_template *sht = sdev->host->hostt;
698 struct scsi_device *tmp_sdev;
699
700 if (!sht->track_queue_depth)
701 return;
702
703 shost_for_each_device(tmp_sdev, sdev->host) {
704 if (tmp_sdev->channel != sdev->channel ||
705 tmp_sdev->id != sdev->id)
706 continue;
707 /*
708 * We do not know the number of commands that were at
709 * the device when we got the queue full so we start
710 * from the highest possible value and work our way down.
711 */
712 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
713 }
714}
715
716/**
717 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
718 * @scmd: SCSI cmd to examine.
719 *
720 * Notes:
721 * This is *only* called when we are examining the status of commands
722 * queued during error recovery. the main difference here is that we
723 * don't allow for the possibility of retries here, and we are a lot
724 * more restrictive about what we consider acceptable.
725 */
726static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
727{
728 /*
729 * first check the host byte, to see if there is anything in there
730 * that would indicate what we need to do.
731 */
732 if (host_byte(scmd->result) == DID_RESET) {
733 /*
734 * rats. we are already in the error handler, so we now
735 * get to try and figure out what to do next. if the sense
736 * is valid, we have a pretty good idea of what to do.
737 * if not, we mark it as FAILED.
738 */
739 return scsi_check_sense(scmd);
740 }
741 if (host_byte(scmd->result) != DID_OK)
742 return FAILED;
743
744 /*
745 * now, check the status byte to see if this indicates
746 * anything special.
747 */
748 switch (get_status_byte(scmd)) {
749 case SAM_STAT_GOOD:
750 scsi_handle_queue_ramp_up(scmd->device);
751 fallthrough;
752 case SAM_STAT_COMMAND_TERMINATED:
753 return SUCCESS;
754 case SAM_STAT_CHECK_CONDITION:
755 return scsi_check_sense(scmd);
756 case SAM_STAT_CONDITION_MET:
757 case SAM_STAT_INTERMEDIATE:
758 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
759 /*
760 * who knows? FIXME(eric)
761 */
762 return SUCCESS;
763 case SAM_STAT_RESERVATION_CONFLICT:
764 if (scmd->cmnd[0] == TEST_UNIT_READY)
765 /* it is a success, we probed the device and
766 * found it */
767 return SUCCESS;
768 /* otherwise, we failed to send the command */
769 return FAILED;
770 case SAM_STAT_TASK_SET_FULL:
771 scsi_handle_queue_full(scmd->device);
772 fallthrough;
773 case SAM_STAT_BUSY:
774 return NEEDS_RETRY;
775 default:
776 return FAILED;
777 }
778 return FAILED;
779}
780
781/**
782 * scsi_eh_done - Completion function for error handling.
783 * @scmd: Cmd that is done.
784 */
785static void scsi_eh_done(struct scsi_cmnd *scmd)
786{
787 struct completion *eh_action;
788
789 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
790 "%s result: %x\n", __func__, scmd->result));
791
792 eh_action = scmd->device->host->eh_action;
793 if (eh_action)
794 complete(eh_action);
795}
796
797/**
798 * scsi_try_host_reset - ask host adapter to reset itself
799 * @scmd: SCSI cmd to send host reset.
800 */
801static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
802{
803 unsigned long flags;
804 enum scsi_disposition rtn;
805 struct Scsi_Host *host = scmd->device->host;
806 struct scsi_host_template *hostt = host->hostt;
807
808 SCSI_LOG_ERROR_RECOVERY(3,
809 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
810
811 if (!hostt->eh_host_reset_handler)
812 return FAILED;
813
814 rtn = hostt->eh_host_reset_handler(scmd);
815
816 if (rtn == SUCCESS) {
817 if (!hostt->skip_settle_delay)
818 ssleep(HOST_RESET_SETTLE_TIME);
819 spin_lock_irqsave(host->host_lock, flags);
820 scsi_report_bus_reset(host, scmd_channel(scmd));
821 spin_unlock_irqrestore(host->host_lock, flags);
822 }
823
824 return rtn;
825}
826
827/**
828 * scsi_try_bus_reset - ask host to perform a bus reset
829 * @scmd: SCSI cmd to send bus reset.
830 */
831static enum scsi_disposition scsi_try_bus_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, scmd_printk(KERN_INFO, scmd,
839 "%s: Snd Bus RST\n", __func__));
840
841 if (!hostt->eh_bus_reset_handler)
842 return FAILED;
843
844 rtn = hostt->eh_bus_reset_handler(scmd);
845
846 if (rtn == SUCCESS) {
847 if (!hostt->skip_settle_delay)
848 ssleep(BUS_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
857static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
858{
859 sdev->was_reset = 1;
860 sdev->expecting_cc_ua = 1;
861}
862
863/**
864 * scsi_try_target_reset - Ask host to perform a target reset
865 * @scmd: SCSI cmd used to send a target reset
866 *
867 * Notes:
868 * There is no timeout for this operation. if this operation is
869 * unreliable for a given host, then the host itself needs to put a
870 * timer on it, and set the host back to a consistent state prior to
871 * returning.
872 */
873static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
874{
875 unsigned long flags;
876 enum scsi_disposition rtn;
877 struct Scsi_Host *host = scmd->device->host;
878 struct scsi_host_template *hostt = host->hostt;
879
880 if (!hostt->eh_target_reset_handler)
881 return FAILED;
882
883 rtn = hostt->eh_target_reset_handler(scmd);
884 if (rtn == SUCCESS) {
885 spin_lock_irqsave(host->host_lock, flags);
886 __starget_for_each_device(scsi_target(scmd->device), NULL,
887 __scsi_report_device_reset);
888 spin_unlock_irqrestore(host->host_lock, flags);
889 }
890
891 return rtn;
892}
893
894/**
895 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
896 * @scmd: SCSI cmd used to send BDR
897 *
898 * Notes:
899 * There is no timeout for this operation. if this operation is
900 * unreliable for a given host, then the host itself needs to put a
901 * timer on it, and set the host back to a consistent state prior to
902 * returning.
903 */
904static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
905{
906 enum scsi_disposition rtn;
907 struct scsi_host_template *hostt = scmd->device->host->hostt;
908
909 if (!hostt->eh_device_reset_handler)
910 return FAILED;
911
912 rtn = hostt->eh_device_reset_handler(scmd);
913 if (rtn == SUCCESS)
914 __scsi_report_device_reset(scmd->device, NULL);
915 return rtn;
916}
917
918/**
919 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
920 * @hostt: SCSI driver host template
921 * @scmd: SCSI cmd used to send a target reset
922 *
923 * Return value:
924 * SUCCESS, FAILED, or FAST_IO_FAIL
925 *
926 * Notes:
927 * SUCCESS does not necessarily indicate that the command
928 * has been aborted; it only indicates that the LLDDs
929 * has cleared all references to that command.
930 * LLDDs should return FAILED only if an abort was required
931 * but could not be executed. LLDDs should return FAST_IO_FAIL
932 * if the device is temporarily unavailable (eg due to a
933 * link down on FibreChannel)
934 */
935static enum scsi_disposition
936scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
937{
938 if (!hostt->eh_abort_handler)
939 return FAILED;
940
941 return hostt->eh_abort_handler(scmd);
942}
943
944static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
945{
946 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
947 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
948 if (scsi_try_target_reset(scmd) != SUCCESS)
949 if (scsi_try_bus_reset(scmd) != SUCCESS)
950 scsi_try_host_reset(scmd);
951}
952
953/**
954 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
955 * @scmd: SCSI command structure to hijack
956 * @ses: structure to save restore information
957 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
958 * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
959 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
960 *
961 * This function is used to save a scsi command information before re-execution
962 * as part of the error recovery process. If @sense_bytes is 0 the command
963 * sent must be one that does not transfer any data. If @sense_bytes != 0
964 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
965 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
966 */
967void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
968 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
969{
970 struct scsi_device *sdev = scmd->device;
971
972 /*
973 * We need saved copies of a number of fields - this is because
974 * error handling may need to overwrite these with different values
975 * to run different commands, and once error handling is complete,
976 * we will need to restore these values prior to running the actual
977 * command.
978 */
979 ses->cmd_len = scmd->cmd_len;
980 ses->cmnd = scmd->cmnd;
981 ses->data_direction = scmd->sc_data_direction;
982 ses->sdb = scmd->sdb;
983 ses->result = scmd->result;
984 ses->resid_len = scmd->req.resid_len;
985 ses->underflow = scmd->underflow;
986 ses->prot_op = scmd->prot_op;
987 ses->eh_eflags = scmd->eh_eflags;
988
989 scmd->prot_op = SCSI_PROT_NORMAL;
990 scmd->eh_eflags = 0;
991 scmd->cmnd = ses->eh_cmnd;
992 memset(scmd->cmnd, 0, BLK_MAX_CDB);
993 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
994 scmd->result = 0;
995 scmd->req.resid_len = 0;
996
997 if (sense_bytes) {
998 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
999 sense_bytes);
1000 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1001 scmd->sdb.length);
1002 scmd->sdb.table.sgl = &ses->sense_sgl;
1003 scmd->sc_data_direction = DMA_FROM_DEVICE;
1004 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1005 scmd->cmnd[0] = REQUEST_SENSE;
1006 scmd->cmnd[4] = scmd->sdb.length;
1007 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1008 } else {
1009 scmd->sc_data_direction = DMA_NONE;
1010 if (cmnd) {
1011 BUG_ON(cmnd_size > BLK_MAX_CDB);
1012 memcpy(scmd->cmnd, cmnd, cmnd_size);
1013 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1014 }
1015 }
1016
1017 scmd->underflow = 0;
1018
1019 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1020 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1021 (sdev->lun << 5 & 0xe0);
1022
1023 /*
1024 * Zero the sense buffer. The scsi spec mandates that any
1025 * untransferred sense data should be interpreted as being zero.
1026 */
1027 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1028}
1029EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1030
1031/**
1032 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
1033 * @scmd: SCSI command structure to restore
1034 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
1035 *
1036 * Undo any damage done by above scsi_eh_prep_cmnd().
1037 */
1038void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1039{
1040 /*
1041 * Restore original data
1042 */
1043 scmd->cmd_len = ses->cmd_len;
1044 scmd->cmnd = ses->cmnd;
1045 scmd->sc_data_direction = ses->data_direction;
1046 scmd->sdb = ses->sdb;
1047 scmd->result = ses->result;
1048 scmd->req.resid_len = ses->resid_len;
1049 scmd->underflow = ses->underflow;
1050 scmd->prot_op = ses->prot_op;
1051 scmd->eh_eflags = ses->eh_eflags;
1052}
1053EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1054
1055/**
1056 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1057 * @scmd: SCSI command structure to hijack
1058 * @cmnd: CDB to send
1059 * @cmnd_size: size in bytes of @cmnd
1060 * @timeout: timeout for this request
1061 * @sense_bytes: size of sense data to copy or 0
1062 *
1063 * This function is used to send a scsi command down to a target device
1064 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1065 *
1066 * Return value:
1067 * SUCCESS or FAILED or NEEDS_RETRY
1068 */
1069static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1070 unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1071{
1072 struct scsi_device *sdev = scmd->device;
1073 struct Scsi_Host *shost = sdev->host;
1074 DECLARE_COMPLETION_ONSTACK(done);
1075 unsigned long timeleft = timeout, delay;
1076 struct scsi_eh_save ses;
1077 const unsigned long stall_for = msecs_to_jiffies(100);
1078 int rtn;
1079
1080retry:
1081 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1082 shost->eh_action = &done;
1083
1084 scsi_log_send(scmd);
1085 scmd->scsi_done = scsi_eh_done;
1086
1087 /*
1088 * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1089 * change the SCSI device state after we have examined it and before
1090 * .queuecommand() is called.
1091 */
1092 mutex_lock(&sdev->state_mutex);
1093 while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1094 mutex_unlock(&sdev->state_mutex);
1095 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1096 "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1097 SDEV_BLOCK));
1098 delay = min(timeleft, stall_for);
1099 timeleft -= delay;
1100 msleep(jiffies_to_msecs(delay));
1101 mutex_lock(&sdev->state_mutex);
1102 }
1103 if (sdev->sdev_state != SDEV_BLOCK)
1104 rtn = shost->hostt->queuecommand(shost, scmd);
1105 else
1106 rtn = FAILED;
1107 mutex_unlock(&sdev->state_mutex);
1108
1109 if (rtn) {
1110 if (timeleft > stall_for) {
1111 scsi_eh_restore_cmnd(scmd, &ses);
1112 timeleft -= stall_for;
1113 msleep(jiffies_to_msecs(stall_for));
1114 goto retry;
1115 }
1116 /* signal not to enter either branch of the if () below */
1117 timeleft = 0;
1118 rtn = FAILED;
1119 } else {
1120 timeleft = wait_for_completion_timeout(&done, timeout);
1121 rtn = SUCCESS;
1122 }
1123
1124 shost->eh_action = NULL;
1125
1126 scsi_log_completion(scmd, rtn);
1127
1128 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1129 "%s timeleft: %ld\n",
1130 __func__, timeleft));
1131
1132 /*
1133 * If there is time left scsi_eh_done got called, and we will examine
1134 * the actual status codes to see whether the command actually did
1135 * complete normally, else if we have a zero return and no time left,
1136 * the command must still be pending, so abort it and return FAILED.
1137 * If we never actually managed to issue the command, because
1138 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1139 * value above (so don't execute either branch of the if)
1140 */
1141 if (timeleft) {
1142 rtn = scsi_eh_completed_normally(scmd);
1143 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1144 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1145
1146 switch (rtn) {
1147 case SUCCESS:
1148 case NEEDS_RETRY:
1149 case FAILED:
1150 break;
1151 case ADD_TO_MLQUEUE:
1152 rtn = NEEDS_RETRY;
1153 break;
1154 default:
1155 rtn = FAILED;
1156 break;
1157 }
1158 } else if (rtn != FAILED) {
1159 scsi_abort_eh_cmnd(scmd);
1160 rtn = FAILED;
1161 }
1162
1163 scsi_eh_restore_cmnd(scmd, &ses);
1164
1165 return rtn;
1166}
1167
1168/**
1169 * scsi_request_sense - Request sense data from a particular target.
1170 * @scmd: SCSI cmd for request sense.
1171 *
1172 * Notes:
1173 * Some hosts automatically obtain this information, others require
1174 * that we obtain it on our own. This function will *not* return until
1175 * the command either times out, or it completes.
1176 */
1177static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1178{
1179 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1180}
1181
1182static enum scsi_disposition
1183scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1184{
1185 if (!blk_rq_is_passthrough(scmd->request)) {
1186 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1187 if (sdrv->eh_action)
1188 rtn = sdrv->eh_action(scmd, rtn);
1189 }
1190 return rtn;
1191}
1192
1193/**
1194 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1195 * @scmd: Original SCSI cmd that eh has finished.
1196 * @done_q: Queue for processed commands.
1197 *
1198 * Notes:
1199 * We don't want to use the normal command completion while we are are
1200 * still handling errors - it may cause other commands to be queued,
1201 * and that would disturb what we are doing. Thus we really want to
1202 * keep a list of pending commands for final completion, and once we
1203 * are ready to leave error handling we handle completion for real.
1204 */
1205void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1206{
1207 list_move_tail(&scmd->eh_entry, done_q);
1208}
1209EXPORT_SYMBOL(scsi_eh_finish_cmd);
1210
1211/**
1212 * scsi_eh_get_sense - Get device sense data.
1213 * @work_q: Queue of commands to process.
1214 * @done_q: Queue of processed commands.
1215 *
1216 * Description:
1217 * See if we need to request sense information. if so, then get it
1218 * now, so we have a better idea of what to do.
1219 *
1220 * Notes:
1221 * This has the unfortunate side effect that if a shost adapter does
1222 * not automatically request sense information, we end up shutting
1223 * it down before we request it.
1224 *
1225 * All drivers should request sense information internally these days,
1226 * so for now all I have to say is tough noogies if you end up in here.
1227 *
1228 * XXX: Long term this code should go away, but that needs an audit of
1229 * all LLDDs first.
1230 */
1231int scsi_eh_get_sense(struct list_head *work_q,
1232 struct list_head *done_q)
1233{
1234 struct scsi_cmnd *scmd, *next;
1235 struct Scsi_Host *shost;
1236 enum scsi_disposition rtn;
1237
1238 /*
1239 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1240 * should not get sense.
1241 */
1242 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1243 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1244 SCSI_SENSE_VALID(scmd))
1245 continue;
1246
1247 shost = scmd->device->host;
1248 if (scsi_host_eh_past_deadline(shost)) {
1249 SCSI_LOG_ERROR_RECOVERY(3,
1250 scmd_printk(KERN_INFO, scmd,
1251 "%s: skip request sense, past eh deadline\n",
1252 current->comm));
1253 break;
1254 }
1255 if (!scsi_status_is_check_condition(scmd->result))
1256 /*
1257 * don't request sense if there's no check condition
1258 * status because the error we're processing isn't one
1259 * that has a sense code (and some devices get
1260 * confused by sense requests out of the blue)
1261 */
1262 continue;
1263
1264 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1265 "%s: requesting sense\n",
1266 current->comm));
1267 rtn = scsi_request_sense(scmd);
1268 if (rtn != SUCCESS)
1269 continue;
1270
1271 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1272 "sense requested, result %x\n", scmd->result));
1273 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1274
1275 rtn = scsi_decide_disposition(scmd);
1276
1277 /*
1278 * if the result was normal, then just pass it along to the
1279 * upper level.
1280 */
1281 if (rtn == SUCCESS)
1282 /*
1283 * We don't want this command reissued, just finished
1284 * with the sense data, so set retries to the max
1285 * allowed to ensure it won't get reissued. If the user
1286 * has requested infinite retries, we also want to
1287 * finish this command, so force completion by setting
1288 * retries and allowed to the same value.
1289 */
1290 if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1291 scmd->retries = scmd->allowed = 1;
1292 else
1293 scmd->retries = scmd->allowed;
1294 else if (rtn != NEEDS_RETRY)
1295 continue;
1296
1297 scsi_eh_finish_cmd(scmd, done_q);
1298 }
1299
1300 return list_empty(work_q);
1301}
1302EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1303
1304/**
1305 * scsi_eh_tur - Send TUR to device.
1306 * @scmd: &scsi_cmnd to send TUR
1307 *
1308 * Return value:
1309 * 0 - Device is ready. 1 - Device NOT ready.
1310 */
1311static int scsi_eh_tur(struct scsi_cmnd *scmd)
1312{
1313 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1314 int retry_cnt = 1;
1315 enum scsi_disposition rtn;
1316
1317retry_tur:
1318 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1319 scmd->device->eh_timeout, 0);
1320
1321 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1322 "%s return: %x\n", __func__, rtn));
1323
1324 switch (rtn) {
1325 case NEEDS_RETRY:
1326 if (retry_cnt--)
1327 goto retry_tur;
1328 fallthrough;
1329 case SUCCESS:
1330 return 0;
1331 default:
1332 return 1;
1333 }
1334}
1335
1336/**
1337 * scsi_eh_test_devices - check if devices are responding from error recovery.
1338 * @cmd_list: scsi commands in error recovery.
1339 * @work_q: queue for commands which still need more error recovery
1340 * @done_q: queue for commands which are finished
1341 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1342 *
1343 * Decription:
1344 * Tests if devices are in a working state. Commands to devices now in
1345 * a working state are sent to the done_q while commands to devices which
1346 * are still failing to respond are returned to the work_q for more
1347 * processing.
1348 **/
1349static int scsi_eh_test_devices(struct list_head *cmd_list,
1350 struct list_head *work_q,
1351 struct list_head *done_q, int try_stu)
1352{
1353 struct scsi_cmnd *scmd, *next;
1354 struct scsi_device *sdev;
1355 int finish_cmds;
1356
1357 while (!list_empty(cmd_list)) {
1358 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1359 sdev = scmd->device;
1360
1361 if (!try_stu) {
1362 if (scsi_host_eh_past_deadline(sdev->host)) {
1363 /* Push items back onto work_q */
1364 list_splice_init(cmd_list, work_q);
1365 SCSI_LOG_ERROR_RECOVERY(3,
1366 sdev_printk(KERN_INFO, sdev,
1367 "%s: skip test device, past eh deadline",
1368 current->comm));
1369 break;
1370 }
1371 }
1372
1373 finish_cmds = !scsi_device_online(scmd->device) ||
1374 (try_stu && !scsi_eh_try_stu(scmd) &&
1375 !scsi_eh_tur(scmd)) ||
1376 !scsi_eh_tur(scmd);
1377
1378 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1379 if (scmd->device == sdev) {
1380 if (finish_cmds &&
1381 (try_stu ||
1382 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1383 scsi_eh_finish_cmd(scmd, done_q);
1384 else
1385 list_move_tail(&scmd->eh_entry, work_q);
1386 }
1387 }
1388 return list_empty(work_q);
1389}
1390
1391/**
1392 * scsi_eh_try_stu - Send START_UNIT to device.
1393 * @scmd: &scsi_cmnd to send START_UNIT
1394 *
1395 * Return value:
1396 * 0 - Device is ready. 1 - Device NOT ready.
1397 */
1398static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1399{
1400 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1401
1402 if (scmd->device->allow_restart) {
1403 int i;
1404 enum scsi_disposition rtn = NEEDS_RETRY;
1405
1406 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1407 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1408
1409 if (rtn == SUCCESS)
1410 return 0;
1411 }
1412
1413 return 1;
1414}
1415
1416 /**
1417 * scsi_eh_stu - send START_UNIT if needed
1418 * @shost: &scsi host being recovered.
1419 * @work_q: &list_head for pending commands.
1420 * @done_q: &list_head for processed commands.
1421 *
1422 * Notes:
1423 * If commands are failing due to not ready, initializing command required,
1424 * try revalidating the device, which will end up sending a start unit.
1425 */
1426static int scsi_eh_stu(struct Scsi_Host *shost,
1427 struct list_head *work_q,
1428 struct list_head *done_q)
1429{
1430 struct scsi_cmnd *scmd, *stu_scmd, *next;
1431 struct scsi_device *sdev;
1432
1433 shost_for_each_device(sdev, shost) {
1434 if (scsi_host_eh_past_deadline(shost)) {
1435 SCSI_LOG_ERROR_RECOVERY(3,
1436 sdev_printk(KERN_INFO, sdev,
1437 "%s: skip START_UNIT, past eh deadline\n",
1438 current->comm));
1439 scsi_device_put(sdev);
1440 break;
1441 }
1442 stu_scmd = NULL;
1443 list_for_each_entry(scmd, work_q, eh_entry)
1444 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1445 scsi_check_sense(scmd) == FAILED ) {
1446 stu_scmd = scmd;
1447 break;
1448 }
1449
1450 if (!stu_scmd)
1451 continue;
1452
1453 SCSI_LOG_ERROR_RECOVERY(3,
1454 sdev_printk(KERN_INFO, sdev,
1455 "%s: Sending START_UNIT\n",
1456 current->comm));
1457
1458 if (!scsi_eh_try_stu(stu_scmd)) {
1459 if (!scsi_device_online(sdev) ||
1460 !scsi_eh_tur(stu_scmd)) {
1461 list_for_each_entry_safe(scmd, next,
1462 work_q, eh_entry) {
1463 if (scmd->device == sdev &&
1464 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1465 scsi_eh_finish_cmd(scmd, done_q);
1466 }
1467 }
1468 } else {
1469 SCSI_LOG_ERROR_RECOVERY(3,
1470 sdev_printk(KERN_INFO, sdev,
1471 "%s: START_UNIT failed\n",
1472 current->comm));
1473 }
1474 }
1475
1476 return list_empty(work_q);
1477}
1478
1479
1480/**
1481 * scsi_eh_bus_device_reset - send bdr if needed
1482 * @shost: scsi host being recovered.
1483 * @work_q: &list_head for pending commands.
1484 * @done_q: &list_head for processed commands.
1485 *
1486 * Notes:
1487 * Try a bus device reset. Still, look to see whether we have multiple
1488 * devices that are jammed or not - if we have multiple devices, it
1489 * makes no sense to try bus_device_reset - we really would need to try
1490 * a bus_reset instead.
1491 */
1492static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1493 struct list_head *work_q,
1494 struct list_head *done_q)
1495{
1496 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1497 struct scsi_device *sdev;
1498 enum scsi_disposition rtn;
1499
1500 shost_for_each_device(sdev, shost) {
1501 if (scsi_host_eh_past_deadline(shost)) {
1502 SCSI_LOG_ERROR_RECOVERY(3,
1503 sdev_printk(KERN_INFO, sdev,
1504 "%s: skip BDR, past eh deadline\n",
1505 current->comm));
1506 scsi_device_put(sdev);
1507 break;
1508 }
1509 bdr_scmd = NULL;
1510 list_for_each_entry(scmd, work_q, eh_entry)
1511 if (scmd->device == sdev) {
1512 bdr_scmd = scmd;
1513 break;
1514 }
1515
1516 if (!bdr_scmd)
1517 continue;
1518
1519 SCSI_LOG_ERROR_RECOVERY(3,
1520 sdev_printk(KERN_INFO, sdev,
1521 "%s: Sending BDR\n", current->comm));
1522 rtn = scsi_try_bus_device_reset(bdr_scmd);
1523 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1524 if (!scsi_device_online(sdev) ||
1525 rtn == FAST_IO_FAIL ||
1526 !scsi_eh_tur(bdr_scmd)) {
1527 list_for_each_entry_safe(scmd, next,
1528 work_q, eh_entry) {
1529 if (scmd->device == sdev &&
1530 scsi_eh_action(scmd, rtn) != FAILED)
1531 scsi_eh_finish_cmd(scmd,
1532 done_q);
1533 }
1534 }
1535 } else {
1536 SCSI_LOG_ERROR_RECOVERY(3,
1537 sdev_printk(KERN_INFO, sdev,
1538 "%s: BDR failed\n", current->comm));
1539 }
1540 }
1541
1542 return list_empty(work_q);
1543}
1544
1545/**
1546 * scsi_eh_target_reset - send target reset if needed
1547 * @shost: scsi host being recovered.
1548 * @work_q: &list_head for pending commands.
1549 * @done_q: &list_head for processed commands.
1550 *
1551 * Notes:
1552 * Try a target reset.
1553 */
1554static int scsi_eh_target_reset(struct Scsi_Host *shost,
1555 struct list_head *work_q,
1556 struct list_head *done_q)
1557{
1558 LIST_HEAD(tmp_list);
1559 LIST_HEAD(check_list);
1560
1561 list_splice_init(work_q, &tmp_list);
1562
1563 while (!list_empty(&tmp_list)) {
1564 struct scsi_cmnd *next, *scmd;
1565 enum scsi_disposition rtn;
1566 unsigned int id;
1567
1568 if (scsi_host_eh_past_deadline(shost)) {
1569 /* push back on work queue for further processing */
1570 list_splice_init(&check_list, work_q);
1571 list_splice_init(&tmp_list, work_q);
1572 SCSI_LOG_ERROR_RECOVERY(3,
1573 shost_printk(KERN_INFO, shost,
1574 "%s: Skip target reset, past eh deadline\n",
1575 current->comm));
1576 return list_empty(work_q);
1577 }
1578
1579 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1580 id = scmd_id(scmd);
1581
1582 SCSI_LOG_ERROR_RECOVERY(3,
1583 shost_printk(KERN_INFO, shost,
1584 "%s: Sending target reset to target %d\n",
1585 current->comm, id));
1586 rtn = scsi_try_target_reset(scmd);
1587 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1588 SCSI_LOG_ERROR_RECOVERY(3,
1589 shost_printk(KERN_INFO, shost,
1590 "%s: Target reset failed"
1591 " target: %d\n",
1592 current->comm, id));
1593 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1594 if (scmd_id(scmd) != id)
1595 continue;
1596
1597 if (rtn == SUCCESS)
1598 list_move_tail(&scmd->eh_entry, &check_list);
1599 else if (rtn == FAST_IO_FAIL)
1600 scsi_eh_finish_cmd(scmd, done_q);
1601 else
1602 /* push back on work queue for further processing */
1603 list_move(&scmd->eh_entry, work_q);
1604 }
1605 }
1606
1607 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1608}
1609
1610/**
1611 * scsi_eh_bus_reset - send a bus reset
1612 * @shost: &scsi host being recovered.
1613 * @work_q: &list_head for pending commands.
1614 * @done_q: &list_head for processed commands.
1615 */
1616static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1617 struct list_head *work_q,
1618 struct list_head *done_q)
1619{
1620 struct scsi_cmnd *scmd, *chan_scmd, *next;
1621 LIST_HEAD(check_list);
1622 unsigned int channel;
1623 enum scsi_disposition rtn;
1624
1625 /*
1626 * we really want to loop over the various channels, and do this on
1627 * a channel by channel basis. we should also check to see if any
1628 * of the failed commands are on soft_reset devices, and if so, skip
1629 * the reset.
1630 */
1631
1632 for (channel = 0; channel <= shost->max_channel; channel++) {
1633 if (scsi_host_eh_past_deadline(shost)) {
1634 list_splice_init(&check_list, work_q);
1635 SCSI_LOG_ERROR_RECOVERY(3,
1636 shost_printk(KERN_INFO, shost,
1637 "%s: skip BRST, past eh deadline\n",
1638 current->comm));
1639 return list_empty(work_q);
1640 }
1641
1642 chan_scmd = NULL;
1643 list_for_each_entry(scmd, work_q, eh_entry) {
1644 if (channel == scmd_channel(scmd)) {
1645 chan_scmd = scmd;
1646 break;
1647 /*
1648 * FIXME add back in some support for
1649 * soft_reset devices.
1650 */
1651 }
1652 }
1653
1654 if (!chan_scmd)
1655 continue;
1656 SCSI_LOG_ERROR_RECOVERY(3,
1657 shost_printk(KERN_INFO, shost,
1658 "%s: Sending BRST chan: %d\n",
1659 current->comm, channel));
1660 rtn = scsi_try_bus_reset(chan_scmd);
1661 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1662 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1663 if (channel == scmd_channel(scmd)) {
1664 if (rtn == FAST_IO_FAIL)
1665 scsi_eh_finish_cmd(scmd,
1666 done_q);
1667 else
1668 list_move_tail(&scmd->eh_entry,
1669 &check_list);
1670 }
1671 }
1672 } else {
1673 SCSI_LOG_ERROR_RECOVERY(3,
1674 shost_printk(KERN_INFO, shost,
1675 "%s: BRST failed chan: %d\n",
1676 current->comm, channel));
1677 }
1678 }
1679 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1680}
1681
1682/**
1683 * scsi_eh_host_reset - send a host reset
1684 * @shost: host to be reset.
1685 * @work_q: &list_head for pending commands.
1686 * @done_q: &list_head for processed commands.
1687 */
1688static int scsi_eh_host_reset(struct Scsi_Host *shost,
1689 struct list_head *work_q,
1690 struct list_head *done_q)
1691{
1692 struct scsi_cmnd *scmd, *next;
1693 LIST_HEAD(check_list);
1694 enum scsi_disposition rtn;
1695
1696 if (!list_empty(work_q)) {
1697 scmd = list_entry(work_q->next,
1698 struct scsi_cmnd, eh_entry);
1699
1700 SCSI_LOG_ERROR_RECOVERY(3,
1701 shost_printk(KERN_INFO, shost,
1702 "%s: Sending HRST\n",
1703 current->comm));
1704
1705 rtn = scsi_try_host_reset(scmd);
1706 if (rtn == SUCCESS) {
1707 list_splice_init(work_q, &check_list);
1708 } else if (rtn == FAST_IO_FAIL) {
1709 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1710 scsi_eh_finish_cmd(scmd, done_q);
1711 }
1712 } else {
1713 SCSI_LOG_ERROR_RECOVERY(3,
1714 shost_printk(KERN_INFO, shost,
1715 "%s: HRST failed\n",
1716 current->comm));
1717 }
1718 }
1719 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1720}
1721
1722/**
1723 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1724 * @work_q: &list_head for pending commands.
1725 * @done_q: &list_head for processed commands.
1726 */
1727static void scsi_eh_offline_sdevs(struct list_head *work_q,
1728 struct list_head *done_q)
1729{
1730 struct scsi_cmnd *scmd, *next;
1731 struct scsi_device *sdev;
1732
1733 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1734 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1735 "not ready after error recovery\n");
1736 sdev = scmd->device;
1737
1738 mutex_lock(&sdev->state_mutex);
1739 scsi_device_set_state(sdev, SDEV_OFFLINE);
1740 mutex_unlock(&sdev->state_mutex);
1741
1742 scsi_eh_finish_cmd(scmd, done_q);
1743 }
1744 return;
1745}
1746
1747/**
1748 * scsi_noretry_cmd - determine if command should be failed fast
1749 * @scmd: SCSI cmd to examine.
1750 */
1751int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1752{
1753 switch (host_byte(scmd->result)) {
1754 case DID_OK:
1755 break;
1756 case DID_TIME_OUT:
1757 goto check_type;
1758 case DID_BUS_BUSY:
1759 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1760 case DID_PARITY:
1761 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1762 case DID_ERROR:
1763 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1764 return 0;
1765 fallthrough;
1766 case DID_SOFT_ERROR:
1767 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1768 }
1769
1770 if (!scsi_status_is_check_condition(scmd->result))
1771 return 0;
1772
1773check_type:
1774 /*
1775 * assume caller has checked sense and determined
1776 * the check condition was retryable.
1777 */
1778 if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1779 blk_rq_is_passthrough(scmd->request))
1780 return 1;
1781
1782 return 0;
1783}
1784
1785/**
1786 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1787 * @scmd: SCSI cmd to examine.
1788 *
1789 * Notes:
1790 * This is *only* called when we are examining the status after sending
1791 * out the actual data command. any commands that are queued for error
1792 * recovery (e.g. test_unit_ready) do *not* come through here.
1793 *
1794 * When this routine returns failed, it means the error handler thread
1795 * is woken. In cases where the error code indicates an error that
1796 * doesn't require the error handler read (i.e. we don't need to
1797 * abort/reset), this function should return SUCCESS.
1798 */
1799enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1800{
1801 enum scsi_disposition rtn;
1802
1803 /*
1804 * if the device is offline, then we clearly just pass the result back
1805 * up to the top level.
1806 */
1807 if (!scsi_device_online(scmd->device)) {
1808 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1809 "%s: device offline - report as SUCCESS\n", __func__));
1810 return SUCCESS;
1811 }
1812
1813 /*
1814 * first check the host byte, to see if there is anything in there
1815 * that would indicate what we need to do.
1816 */
1817 switch (host_byte(scmd->result)) {
1818 case DID_PASSTHROUGH:
1819 /*
1820 * no matter what, pass this through to the upper layer.
1821 * nuke this special code so that it looks like we are saying
1822 * did_ok.
1823 */
1824 scmd->result &= 0xff00ffff;
1825 return SUCCESS;
1826 case DID_OK:
1827 /*
1828 * looks good. drop through, and check the next byte.
1829 */
1830 break;
1831 case DID_ABORT:
1832 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1833 set_host_byte(scmd, DID_TIME_OUT);
1834 return SUCCESS;
1835 }
1836 fallthrough;
1837 case DID_NO_CONNECT:
1838 case DID_BAD_TARGET:
1839 /*
1840 * note - this means that we just report the status back
1841 * to the top level driver, not that we actually think
1842 * that it indicates SUCCESS.
1843 */
1844 return SUCCESS;
1845 case DID_SOFT_ERROR:
1846 /*
1847 * when the low level driver returns did_soft_error,
1848 * it is responsible for keeping an internal retry counter
1849 * in order to avoid endless loops (db)
1850 */
1851 goto maybe_retry;
1852 case DID_IMM_RETRY:
1853 return NEEDS_RETRY;
1854
1855 case DID_REQUEUE:
1856 return ADD_TO_MLQUEUE;
1857 case DID_TRANSPORT_DISRUPTED:
1858 /*
1859 * LLD/transport was disrupted during processing of the IO.
1860 * The transport class is now blocked/blocking,
1861 * and the transport will decide what to do with the IO
1862 * based on its timers and recovery capablilities if
1863 * there are enough retries.
1864 */
1865 goto maybe_retry;
1866 case DID_TRANSPORT_FAILFAST:
1867 /*
1868 * The transport decided to failfast the IO (most likely
1869 * the fast io fail tmo fired), so send IO directly upwards.
1870 */
1871 return SUCCESS;
1872 case DID_TRANSPORT_MARGINAL:
1873 /*
1874 * caller has decided not to do retries on
1875 * abort success, so send IO directly upwards
1876 */
1877 return SUCCESS;
1878 case DID_ERROR:
1879 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1880 /*
1881 * execute reservation conflict processing code
1882 * lower down
1883 */
1884 break;
1885 fallthrough;
1886 case DID_BUS_BUSY:
1887 case DID_PARITY:
1888 goto maybe_retry;
1889 case DID_TIME_OUT:
1890 /*
1891 * when we scan the bus, we get timeout messages for
1892 * these commands if there is no device available.
1893 * other hosts report did_no_connect for the same thing.
1894 */
1895 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1896 scmd->cmnd[0] == INQUIRY)) {
1897 return SUCCESS;
1898 } else {
1899 return FAILED;
1900 }
1901 case DID_RESET:
1902 return SUCCESS;
1903 default:
1904 return FAILED;
1905 }
1906
1907 /*
1908 * check the status byte to see if this indicates anything special.
1909 */
1910 switch (get_status_byte(scmd)) {
1911 case SAM_STAT_TASK_SET_FULL:
1912 scsi_handle_queue_full(scmd->device);
1913 /*
1914 * the case of trying to send too many commands to a
1915 * tagged queueing device.
1916 */
1917 fallthrough;
1918 case SAM_STAT_BUSY:
1919 /*
1920 * device can't talk to us at the moment. Should only
1921 * occur (SAM-3) when the task queue is empty, so will cause
1922 * the empty queue handling to trigger a stall in the
1923 * device.
1924 */
1925 return ADD_TO_MLQUEUE;
1926 case SAM_STAT_GOOD:
1927 if (scmd->cmnd[0] == REPORT_LUNS)
1928 scmd->device->sdev_target->expecting_lun_change = 0;
1929 scsi_handle_queue_ramp_up(scmd->device);
1930 fallthrough;
1931 case SAM_STAT_COMMAND_TERMINATED:
1932 return SUCCESS;
1933 case SAM_STAT_TASK_ABORTED:
1934 goto maybe_retry;
1935 case SAM_STAT_CHECK_CONDITION:
1936 rtn = scsi_check_sense(scmd);
1937 if (rtn == NEEDS_RETRY)
1938 goto maybe_retry;
1939 /* if rtn == FAILED, we have no sense information;
1940 * returning FAILED will wake the error handler thread
1941 * to collect the sense and redo the decide
1942 * disposition */
1943 return rtn;
1944 case SAM_STAT_CONDITION_MET:
1945 case SAM_STAT_INTERMEDIATE:
1946 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
1947 case SAM_STAT_ACA_ACTIVE:
1948 /*
1949 * who knows? FIXME(eric)
1950 */
1951 return SUCCESS;
1952
1953 case SAM_STAT_RESERVATION_CONFLICT:
1954 sdev_printk(KERN_INFO, scmd->device,
1955 "reservation conflict\n");
1956 set_host_byte(scmd, DID_NEXUS_FAILURE);
1957 return SUCCESS; /* causes immediate i/o error */
1958 default:
1959 return FAILED;
1960 }
1961 return FAILED;
1962
1963maybe_retry:
1964
1965 /* we requeue for retry because the error was retryable, and
1966 * the request was not marked fast fail. Note that above,
1967 * even if the request is marked fast fail, we still requeue
1968 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1969 if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
1970 return NEEDS_RETRY;
1971 } else {
1972 /*
1973 * no more retries - report this one back to upper level.
1974 */
1975 return SUCCESS;
1976 }
1977}
1978
1979static void eh_lock_door_done(struct request *req, blk_status_t status)
1980{
1981 blk_put_request(req);
1982}
1983
1984/**
1985 * scsi_eh_lock_door - Prevent medium removal for the specified device
1986 * @sdev: SCSI device to prevent medium removal
1987 *
1988 * Locking:
1989 * We must be called from process context.
1990 *
1991 * Notes:
1992 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1993 * head of the devices request queue, and continue.
1994 */
1995static void scsi_eh_lock_door(struct scsi_device *sdev)
1996{
1997 struct request *req;
1998 struct scsi_request *rq;
1999
2000 req = blk_get_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
2001 if (IS_ERR(req))
2002 return;
2003 rq = scsi_req(req);
2004
2005 rq->cmd[0] = ALLOW_MEDIUM_REMOVAL;
2006 rq->cmd[1] = 0;
2007 rq->cmd[2] = 0;
2008 rq->cmd[3] = 0;
2009 rq->cmd[4] = SCSI_REMOVAL_PREVENT;
2010 rq->cmd[5] = 0;
2011 rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
2012
2013 req->rq_flags |= RQF_QUIET;
2014 req->timeout = 10 * HZ;
2015 rq->retries = 5;
2016
2017 blk_execute_rq_nowait(NULL, req, 1, eh_lock_door_done);
2018}
2019
2020/**
2021 * scsi_restart_operations - restart io operations to the specified host.
2022 * @shost: Host we are restarting.
2023 *
2024 * Notes:
2025 * When we entered the error handler, we blocked all further i/o to
2026 * this device. we need to 'reverse' this process.
2027 */
2028static void scsi_restart_operations(struct Scsi_Host *shost)
2029{
2030 struct scsi_device *sdev;
2031 unsigned long flags;
2032
2033 /*
2034 * If the door was locked, we need to insert a door lock request
2035 * onto the head of the SCSI request queue for the device. There
2036 * is no point trying to lock the door of an off-line device.
2037 */
2038 shost_for_each_device(sdev, shost) {
2039 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2040 scsi_eh_lock_door(sdev);
2041 sdev->was_reset = 0;
2042 }
2043 }
2044
2045 /*
2046 * next free up anything directly waiting upon the host. this
2047 * will be requests for character device operations, and also for
2048 * ioctls to queued block devices.
2049 */
2050 SCSI_LOG_ERROR_RECOVERY(3,
2051 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2052
2053 spin_lock_irqsave(shost->host_lock, flags);
2054 if (scsi_host_set_state(shost, SHOST_RUNNING))
2055 if (scsi_host_set_state(shost, SHOST_CANCEL))
2056 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2057 spin_unlock_irqrestore(shost->host_lock, flags);
2058
2059 wake_up(&shost->host_wait);
2060
2061 /*
2062 * finally we need to re-initiate requests that may be pending. we will
2063 * have had everything blocked while error handling is taking place, and
2064 * now that error recovery is done, we will need to ensure that these
2065 * requests are started.
2066 */
2067 scsi_run_host_queues(shost);
2068
2069 /*
2070 * if eh is active and host_eh_scheduled is pending we need to re-run
2071 * recovery. we do this check after scsi_run_host_queues() to allow
2072 * everything pent up since the last eh run a chance to make forward
2073 * progress before we sync again. Either we'll immediately re-run
2074 * recovery or scsi_device_unbusy() will wake us again when these
2075 * pending commands complete.
2076 */
2077 spin_lock_irqsave(shost->host_lock, flags);
2078 if (shost->host_eh_scheduled)
2079 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2080 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2081 spin_unlock_irqrestore(shost->host_lock, flags);
2082}
2083
2084/**
2085 * scsi_eh_ready_devs - check device ready state and recover if not.
2086 * @shost: host to be recovered.
2087 * @work_q: &list_head for pending commands.
2088 * @done_q: &list_head for processed commands.
2089 */
2090void scsi_eh_ready_devs(struct Scsi_Host *shost,
2091 struct list_head *work_q,
2092 struct list_head *done_q)
2093{
2094 if (!scsi_eh_stu(shost, work_q, done_q))
2095 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2096 if (!scsi_eh_target_reset(shost, work_q, done_q))
2097 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2098 if (!scsi_eh_host_reset(shost, work_q, done_q))
2099 scsi_eh_offline_sdevs(work_q,
2100 done_q);
2101}
2102EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2103
2104/**
2105 * scsi_eh_flush_done_q - finish processed commands or retry them.
2106 * @done_q: list_head of processed commands.
2107 */
2108void scsi_eh_flush_done_q(struct list_head *done_q)
2109{
2110 struct scsi_cmnd *scmd, *next;
2111
2112 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2113 list_del_init(&scmd->eh_entry);
2114 if (scsi_device_online(scmd->device) &&
2115 !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2116 scsi_eh_should_retry_cmd(scmd)) {
2117 SCSI_LOG_ERROR_RECOVERY(3,
2118 scmd_printk(KERN_INFO, scmd,
2119 "%s: flush retry cmd\n",
2120 current->comm));
2121 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2122 } else {
2123 /*
2124 * If just we got sense for the device (called
2125 * scsi_eh_get_sense), scmd->result is already
2126 * set, do not set DID_TIME_OUT.
2127 */
2128 if (!scmd->result)
2129 scmd->result |= (DID_TIME_OUT << 16);
2130 SCSI_LOG_ERROR_RECOVERY(3,
2131 scmd_printk(KERN_INFO, scmd,
2132 "%s: flush finish cmd\n",
2133 current->comm));
2134 scsi_finish_command(scmd);
2135 }
2136 }
2137}
2138EXPORT_SYMBOL(scsi_eh_flush_done_q);
2139
2140/**
2141 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2142 * @shost: Host to unjam.
2143 *
2144 * Notes:
2145 * When we come in here, we *know* that all commands on the bus have
2146 * either completed, failed or timed out. we also know that no further
2147 * commands are being sent to the host, so things are relatively quiet
2148 * and we have freedom to fiddle with things as we wish.
2149 *
2150 * This is only the *default* implementation. it is possible for
2151 * individual drivers to supply their own version of this function, and
2152 * if the maintainer wishes to do this, it is strongly suggested that
2153 * this function be taken as a template and modified. this function
2154 * was designed to correctly handle problems for about 95% of the
2155 * different cases out there, and it should always provide at least a
2156 * reasonable amount of error recovery.
2157 *
2158 * Any command marked 'failed' or 'timeout' must eventually have
2159 * scsi_finish_cmd() called for it. we do all of the retry stuff
2160 * here, so when we restart the host after we return it should have an
2161 * empty queue.
2162 */
2163static void scsi_unjam_host(struct Scsi_Host *shost)
2164{
2165 unsigned long flags;
2166 LIST_HEAD(eh_work_q);
2167 LIST_HEAD(eh_done_q);
2168
2169 spin_lock_irqsave(shost->host_lock, flags);
2170 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2171 spin_unlock_irqrestore(shost->host_lock, flags);
2172
2173 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2174
2175 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2176 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2177
2178 spin_lock_irqsave(shost->host_lock, flags);
2179 if (shost->eh_deadline != -1)
2180 shost->last_reset = 0;
2181 spin_unlock_irqrestore(shost->host_lock, flags);
2182 scsi_eh_flush_done_q(&eh_done_q);
2183}
2184
2185/**
2186 * scsi_error_handler - SCSI error handler thread
2187 * @data: Host for which we are running.
2188 *
2189 * Notes:
2190 * This is the main error handling loop. This is run as a kernel thread
2191 * for every SCSI host and handles all error handling activity.
2192 */
2193int scsi_error_handler(void *data)
2194{
2195 struct Scsi_Host *shost = data;
2196
2197 /*
2198 * We use TASK_INTERRUPTIBLE so that the thread is not
2199 * counted against the load average as a running process.
2200 * We never actually get interrupted because kthread_run
2201 * disables signal delivery for the created thread.
2202 */
2203 while (true) {
2204 /*
2205 * The sequence in kthread_stop() sets the stop flag first
2206 * then wakes the process. To avoid missed wakeups, the task
2207 * should always be in a non running state before the stop
2208 * flag is checked
2209 */
2210 set_current_state(TASK_INTERRUPTIBLE);
2211 if (kthread_should_stop())
2212 break;
2213
2214 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2215 shost->host_failed != scsi_host_busy(shost)) {
2216 SCSI_LOG_ERROR_RECOVERY(1,
2217 shost_printk(KERN_INFO, shost,
2218 "scsi_eh_%d: sleeping\n",
2219 shost->host_no));
2220 schedule();
2221 continue;
2222 }
2223
2224 __set_current_state(TASK_RUNNING);
2225 SCSI_LOG_ERROR_RECOVERY(1,
2226 shost_printk(KERN_INFO, shost,
2227 "scsi_eh_%d: waking up %d/%d/%d\n",
2228 shost->host_no, shost->host_eh_scheduled,
2229 shost->host_failed,
2230 scsi_host_busy(shost)));
2231
2232 /*
2233 * We have a host that is failing for some reason. Figure out
2234 * what we need to do to get it up and online again (if we can).
2235 * If we fail, we end up taking the thing offline.
2236 */
2237 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2238 SCSI_LOG_ERROR_RECOVERY(1,
2239 shost_printk(KERN_ERR, shost,
2240 "scsi_eh_%d: unable to autoresume\n",
2241 shost->host_no));
2242 continue;
2243 }
2244
2245 if (shost->transportt->eh_strategy_handler)
2246 shost->transportt->eh_strategy_handler(shost);
2247 else
2248 scsi_unjam_host(shost);
2249
2250 /* All scmds have been handled */
2251 shost->host_failed = 0;
2252
2253 /*
2254 * Note - if the above fails completely, the action is to take
2255 * individual devices offline and flush the queue of any
2256 * outstanding requests that may have been pending. When we
2257 * restart, we restart any I/O to any other devices on the bus
2258 * which are still online.
2259 */
2260 scsi_restart_operations(shost);
2261 if (!shost->eh_noresume)
2262 scsi_autopm_put_host(shost);
2263 }
2264 __set_current_state(TASK_RUNNING);
2265
2266 SCSI_LOG_ERROR_RECOVERY(1,
2267 shost_printk(KERN_INFO, shost,
2268 "Error handler scsi_eh_%d exiting\n",
2269 shost->host_no));
2270 shost->ehandler = NULL;
2271 return 0;
2272}
2273
2274/*
2275 * Function: scsi_report_bus_reset()
2276 *
2277 * Purpose: Utility function used by low-level drivers to report that
2278 * they have observed a bus reset on the bus being handled.
2279 *
2280 * Arguments: shost - Host in question
2281 * channel - channel on which reset was observed.
2282 *
2283 * Returns: Nothing
2284 *
2285 * Lock status: Host lock must be held.
2286 *
2287 * Notes: This only needs to be called if the reset is one which
2288 * originates from an unknown location. Resets originated
2289 * by the mid-level itself don't need to call this, but there
2290 * should be no harm.
2291 *
2292 * The main purpose of this is to make sure that a CHECK_CONDITION
2293 * is properly treated.
2294 */
2295void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2296{
2297 struct scsi_device *sdev;
2298
2299 __shost_for_each_device(sdev, shost) {
2300 if (channel == sdev_channel(sdev))
2301 __scsi_report_device_reset(sdev, NULL);
2302 }
2303}
2304EXPORT_SYMBOL(scsi_report_bus_reset);
2305
2306/*
2307 * Function: scsi_report_device_reset()
2308 *
2309 * Purpose: Utility function used by low-level drivers to report that
2310 * they have observed a device reset on the device being handled.
2311 *
2312 * Arguments: shost - Host in question
2313 * channel - channel on which reset was observed
2314 * target - target on which reset was observed
2315 *
2316 * Returns: Nothing
2317 *
2318 * Lock status: Host lock must be held
2319 *
2320 * Notes: This only needs to be called if the reset is one which
2321 * originates from an unknown location. Resets originated
2322 * by the mid-level itself don't need to call this, but there
2323 * should be no harm.
2324 *
2325 * The main purpose of this is to make sure that a CHECK_CONDITION
2326 * is properly treated.
2327 */
2328void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2329{
2330 struct scsi_device *sdev;
2331
2332 __shost_for_each_device(sdev, shost) {
2333 if (channel == sdev_channel(sdev) &&
2334 target == sdev_id(sdev))
2335 __scsi_report_device_reset(sdev, NULL);
2336 }
2337}
2338EXPORT_SYMBOL(scsi_report_device_reset);
2339
2340static void
2341scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2342{
2343}
2344
2345/**
2346 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2347 * @dev: scsi_device to operate on
2348 * @arg: reset type (see sg.h)
2349 */
2350int
2351scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2352{
2353 struct scsi_cmnd *scmd;
2354 struct Scsi_Host *shost = dev->host;
2355 struct request *rq;
2356 unsigned long flags;
2357 int error = 0, val;
2358 enum scsi_disposition rtn;
2359
2360 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2361 return -EACCES;
2362
2363 error = get_user(val, arg);
2364 if (error)
2365 return error;
2366
2367 if (scsi_autopm_get_host(shost) < 0)
2368 return -EIO;
2369
2370 error = -EIO;
2371 rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2372 shost->hostt->cmd_size, GFP_KERNEL);
2373 if (!rq)
2374 goto out_put_autopm_host;
2375 blk_rq_init(NULL, rq);
2376
2377 scmd = (struct scsi_cmnd *)(rq + 1);
2378 scsi_init_command(dev, scmd);
2379 scmd->request = rq;
2380 scmd->cmnd = scsi_req(rq)->cmd;
2381
2382 scmd->scsi_done = scsi_reset_provider_done_command;
2383 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2384
2385 scmd->cmd_len = 0;
2386
2387 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2388
2389 spin_lock_irqsave(shost->host_lock, flags);
2390 shost->tmf_in_progress = 1;
2391 spin_unlock_irqrestore(shost->host_lock, flags);
2392
2393 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2394 case SG_SCSI_RESET_NOTHING:
2395 rtn = SUCCESS;
2396 break;
2397 case SG_SCSI_RESET_DEVICE:
2398 rtn = scsi_try_bus_device_reset(scmd);
2399 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2400 break;
2401 fallthrough;
2402 case SG_SCSI_RESET_TARGET:
2403 rtn = scsi_try_target_reset(scmd);
2404 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2405 break;
2406 fallthrough;
2407 case SG_SCSI_RESET_BUS:
2408 rtn = scsi_try_bus_reset(scmd);
2409 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2410 break;
2411 fallthrough;
2412 case SG_SCSI_RESET_HOST:
2413 rtn = scsi_try_host_reset(scmd);
2414 if (rtn == SUCCESS)
2415 break;
2416 fallthrough;
2417 default:
2418 rtn = FAILED;
2419 break;
2420 }
2421
2422 error = (rtn == SUCCESS) ? 0 : -EIO;
2423
2424 spin_lock_irqsave(shost->host_lock, flags);
2425 shost->tmf_in_progress = 0;
2426 spin_unlock_irqrestore(shost->host_lock, flags);
2427
2428 /*
2429 * be sure to wake up anyone who was sleeping or had their queue
2430 * suspended while we performed the TMF.
2431 */
2432 SCSI_LOG_ERROR_RECOVERY(3,
2433 shost_printk(KERN_INFO, shost,
2434 "waking up host to restart after TMF\n"));
2435
2436 wake_up(&shost->host_wait);
2437 scsi_run_host_queues(shost);
2438
2439 kfree(rq);
2440
2441out_put_autopm_host:
2442 scsi_autopm_put_host(shost);
2443 return error;
2444}
2445
2446bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2447 struct scsi_sense_hdr *sshdr)
2448{
2449 return scsi_normalize_sense(cmd->sense_buffer,
2450 SCSI_SENSE_BUFFERSIZE, sshdr);
2451}
2452EXPORT_SYMBOL(scsi_command_normalize_sense);
2453
2454/**
2455 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2456 * @sense_buffer: byte array of sense data
2457 * @sb_len: number of valid bytes in sense_buffer
2458 * @info_out: pointer to 64 integer where 8 or 4 byte information
2459 * field will be placed if found.
2460 *
2461 * Return value:
2462 * true if information field found, false if not found.
2463 */
2464bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2465 u64 *info_out)
2466{
2467 const u8 * ucp;
2468
2469 if (sb_len < 7)
2470 return false;
2471 switch (sense_buffer[0] & 0x7f) {
2472 case 0x70:
2473 case 0x71:
2474 if (sense_buffer[0] & 0x80) {
2475 *info_out = get_unaligned_be32(&sense_buffer[3]);
2476 return true;
2477 }
2478 return false;
2479 case 0x72:
2480 case 0x73:
2481 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2482 0 /* info desc */);
2483 if (ucp && (0xa == ucp[1])) {
2484 *info_out = get_unaligned_be64(&ucp[4]);
2485 return true;
2486 }
2487 return false;
2488 default:
2489 return false;
2490 }
2491}
2492EXPORT_SYMBOL(scsi_get_sense_info_fld);
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(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(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(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(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
213out:
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 */
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(&scmd->eh_entry, &shost->eh_abort_list);
255 spin_unlock_irqrestore(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(shost->tmf_work_q, &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(scsi_cmd_to_rq(scmd))) {
275 struct scsi_driver *sdrv = scsi_cmd_to_driver(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(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(&scmd->eh_entry, &shost->eh_cmd_q);
315 spin_unlock_irqrestore(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(&scmd->rcu, 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(req);
336 struct Scsi_Host *host = scmd->device->host;
337
338 trace_scsi_dispatch_cmd_timeout(scmd);
339 scsi_log_completion(scmd, TIMEOUT_ERROR);
340
341 atomic_inc(&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, &scmd->state))
361 return BLK_EH_DONE;
362 atomic_inc(&scmd->device->iodone_cnt);
363 if (scsi_abort_command(scmd) != SUCCESS) {
364 set_host_byte(scmd, 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(evt_type, sdev->pending_events);
517 schedule_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 scsi_device *sdev = scmd->device;
540 struct scsi_sense_hdr sshdr;
541
542 if (! scsi_command_normalize_sense(scmd, &sshdr))
543 return FAILED; /* no valid sense data */
544
545 scsi_report_sense(sdev, &sshdr);
546
547 if (scsi_sense_is_deferred(&sshdr))
548 return NEEDS_RETRY;
549
550 if (sdev->handler && sdev->handler->check_sense) {
551 enum scsi_disposition rc;
552
553 rc = sdev->handler->check_sense(sdev, &sshdr);
554 if (rc != SCSI_RETURN_NOT_HANDLED)
555 return rc;
556 /* handler does not care. Drop down to default handling */
557 }
558
559 if (scmd->cmnd[0] == TEST_UNIT_READY &&
560 scmd->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER)
561 /*
562 * nasty: for mid-layer issued TURs, we need to return the
563 * actual sense data without any recovery attempt. For eh
564 * issued ones, we need to try to recover and interpret
565 */
566 return SUCCESS;
567
568 /*
569 * Previous logic looked for FILEMARK, EOM or ILI which are
570 * mainly associated with tapes and returned SUCCESS.
571 */
572 if (sshdr.response_code == 0x70) {
573 /* fixed format */
574 if (scmd->sense_buffer[2] & 0xe0)
575 return SUCCESS;
576 } else {
577 /*
578 * descriptor format: look for "stream commands sense data
579 * descriptor" (see SSC-3). Assume single sense data
580 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
581 */
582 if ((sshdr.additional_length > 3) &&
583 (scmd->sense_buffer[8] == 0x4) &&
584 (scmd->sense_buffer[11] & 0xe0))
585 return SUCCESS;
586 }
587
588 switch (sshdr.sense_key) {
589 case NO_SENSE:
590 return SUCCESS;
591 case RECOVERED_ERROR:
592 return /* soft_error */ SUCCESS;
593
594 case ABORTED_COMMAND:
595 if (sshdr.asc == 0x10) /* DIF */
596 return SUCCESS;
597
598 if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
599 return ADD_TO_MLQUEUE;
600 if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
601 sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
602 return ADD_TO_MLQUEUE;
603
604 return NEEDS_RETRY;
605 case NOT_READY:
606 case UNIT_ATTENTION:
607 /*
608 * if we are expecting a cc/ua because of a bus reset that we
609 * performed, treat this just as a retry. otherwise this is
610 * information that we should pass up to the upper-level driver
611 * so that we can deal with it there.
612 */
613 if (scmd->device->expecting_cc_ua) {
614 /*
615 * Because some device does not queue unit
616 * attentions correctly, we carefully check
617 * additional sense code and qualifier so as
618 * not to squash media change unit attention.
619 */
620 if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
621 scmd->device->expecting_cc_ua = 0;
622 return NEEDS_RETRY;
623 }
624 }
625 /*
626 * we might also expect a cc/ua if another LUN on the target
627 * reported a UA with an ASC/ASCQ of 3F 0E -
628 * REPORTED LUNS DATA HAS CHANGED.
629 */
630 if (scmd->device->sdev_target->expecting_lun_change &&
631 sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
632 return NEEDS_RETRY;
633 /*
634 * if the device is in the process of becoming ready, we
635 * should retry.
636 */
637 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
638 return NEEDS_RETRY;
639 /*
640 * if the device is not started, we need to wake
641 * the error handler to start the motor
642 */
643 if (scmd->device->allow_restart &&
644 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
645 return FAILED;
646 /*
647 * Pass the UA upwards for a determination in the completion
648 * functions.
649 */
650 return SUCCESS;
651
652 /* these are not supported */
653 case DATA_PROTECT:
654 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
655 /* Thin provisioning hard threshold reached */
656 set_scsi_ml_byte(scmd, SCSIML_STAT_NOSPC);
657 return SUCCESS;
658 }
659 fallthrough;
660 case COPY_ABORTED:
661 case VOLUME_OVERFLOW:
662 case MISCOMPARE:
663 case BLANK_CHECK:
664 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
665 return SUCCESS;
666
667 case MEDIUM_ERROR:
668 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
669 sshdr.asc == 0x13 || /* AMNF DATA FIELD */
670 sshdr.asc == 0x14) { /* RECORD NOT FOUND */
671 set_scsi_ml_byte(scmd, SCSIML_STAT_MED_ERROR);
672 return SUCCESS;
673 }
674 return NEEDS_RETRY;
675
676 case HARDWARE_ERROR:
677 if (scmd->device->retry_hwerror)
678 return ADD_TO_MLQUEUE;
679 else
680 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
681 fallthrough;
682
683 case ILLEGAL_REQUEST:
684 if (sshdr.asc == 0x20 || /* Invalid command operation code */
685 sshdr.asc == 0x21 || /* Logical block address out of range */
686 sshdr.asc == 0x22 || /* Invalid function */
687 sshdr.asc == 0x24 || /* Invalid field in cdb */
688 sshdr.asc == 0x26 || /* Parameter value invalid */
689 sshdr.asc == 0x27) { /* Write protected */
690 set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
691 }
692 return SUCCESS;
693
694 default:
695 return SUCCESS;
696 }
697}
698EXPORT_SYMBOL_GPL(scsi_check_sense);
699
700static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
701{
702 struct scsi_host_template *sht = sdev->host->hostt;
703 struct scsi_device *tmp_sdev;
704
705 if (!sht->track_queue_depth ||
706 sdev->queue_depth >= sdev->max_queue_depth)
707 return;
708
709 if (time_before(jiffies,
710 sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
711 return;
712
713 if (time_before(jiffies,
714 sdev->last_queue_full_time + sdev->queue_ramp_up_period))
715 return;
716
717 /*
718 * Walk all devices of a target and do
719 * ramp up on them.
720 */
721 shost_for_each_device(tmp_sdev, sdev->host) {
722 if (tmp_sdev->channel != sdev->channel ||
723 tmp_sdev->id != sdev->id ||
724 tmp_sdev->queue_depth == sdev->max_queue_depth)
725 continue;
726
727 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
728 sdev->last_queue_ramp_up = jiffies;
729 }
730}
731
732static void scsi_handle_queue_full(struct scsi_device *sdev)
733{
734 struct scsi_host_template *sht = sdev->host->hostt;
735 struct scsi_device *tmp_sdev;
736
737 if (!sht->track_queue_depth)
738 return;
739
740 shost_for_each_device(tmp_sdev, sdev->host) {
741 if (tmp_sdev->channel != sdev->channel ||
742 tmp_sdev->id != sdev->id)
743 continue;
744 /*
745 * We do not know the number of commands that were at
746 * the device when we got the queue full so we start
747 * from the highest possible value and work our way down.
748 */
749 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
750 }
751}
752
753/**
754 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
755 * @scmd: SCSI cmd to examine.
756 *
757 * Notes:
758 * This is *only* called when we are examining the status of commands
759 * queued during error recovery. the main difference here is that we
760 * don't allow for the possibility of retries here, and we are a lot
761 * more restrictive about what we consider acceptable.
762 */
763static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
764{
765 /*
766 * first check the host byte, to see if there is anything in there
767 * that would indicate what we need to do.
768 */
769 if (host_byte(scmd->result) == DID_RESET) {
770 /*
771 * rats. we are already in the error handler, so we now
772 * get to try and figure out what to do next. if the sense
773 * is valid, we have a pretty good idea of what to do.
774 * if not, we mark it as FAILED.
775 */
776 return scsi_check_sense(scmd);
777 }
778 if (host_byte(scmd->result) != DID_OK)
779 return FAILED;
780
781 /*
782 * now, check the status byte to see if this indicates
783 * anything special.
784 */
785 switch (get_status_byte(scmd)) {
786 case SAM_STAT_GOOD:
787 scsi_handle_queue_ramp_up(scmd->device);
788 fallthrough;
789 case SAM_STAT_COMMAND_TERMINATED:
790 return SUCCESS;
791 case SAM_STAT_CHECK_CONDITION:
792 return scsi_check_sense(scmd);
793 case SAM_STAT_CONDITION_MET:
794 case SAM_STAT_INTERMEDIATE:
795 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
796 /*
797 * who knows? FIXME(eric)
798 */
799 return SUCCESS;
800 case SAM_STAT_RESERVATION_CONFLICT:
801 if (scmd->cmnd[0] == TEST_UNIT_READY)
802 /* it is a success, we probed the device and
803 * found it */
804 return SUCCESS;
805 /* otherwise, we failed to send the command */
806 return FAILED;
807 case SAM_STAT_TASK_SET_FULL:
808 scsi_handle_queue_full(scmd->device);
809 fallthrough;
810 case SAM_STAT_BUSY:
811 return NEEDS_RETRY;
812 default:
813 return FAILED;
814 }
815 return FAILED;
816}
817
818/**
819 * scsi_eh_done - Completion function for error handling.
820 * @scmd: Cmd that is done.
821 */
822void scsi_eh_done(struct scsi_cmnd *scmd)
823{
824 struct completion *eh_action;
825
826 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
827 "%s result: %x\n", __func__, scmd->result));
828
829 eh_action = scmd->device->host->eh_action;
830 if (eh_action)
831 complete(eh_action);
832}
833
834/**
835 * scsi_try_host_reset - ask host adapter to reset itself
836 * @scmd: SCSI cmd to send host reset.
837 */
838static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
839{
840 unsigned long flags;
841 enum scsi_disposition rtn;
842 struct Scsi_Host *host = scmd->device->host;
843 struct scsi_host_template *hostt = host->hostt;
844
845 SCSI_LOG_ERROR_RECOVERY(3,
846 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
847
848 if (!hostt->eh_host_reset_handler)
849 return FAILED;
850
851 rtn = hostt->eh_host_reset_handler(scmd);
852
853 if (rtn == SUCCESS) {
854 if (!hostt->skip_settle_delay)
855 ssleep(HOST_RESET_SETTLE_TIME);
856 spin_lock_irqsave(host->host_lock, flags);
857 scsi_report_bus_reset(host, scmd_channel(scmd));
858 spin_unlock_irqrestore(host->host_lock, flags);
859 }
860
861 return rtn;
862}
863
864/**
865 * scsi_try_bus_reset - ask host to perform a bus reset
866 * @scmd: SCSI cmd to send bus reset.
867 */
868static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
869{
870 unsigned long flags;
871 enum scsi_disposition rtn;
872 struct Scsi_Host *host = scmd->device->host;
873 struct scsi_host_template *hostt = host->hostt;
874
875 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
876 "%s: Snd Bus RST\n", __func__));
877
878 if (!hostt->eh_bus_reset_handler)
879 return FAILED;
880
881 rtn = hostt->eh_bus_reset_handler(scmd);
882
883 if (rtn == SUCCESS) {
884 if (!hostt->skip_settle_delay)
885 ssleep(BUS_RESET_SETTLE_TIME);
886 spin_lock_irqsave(host->host_lock, flags);
887 scsi_report_bus_reset(host, scmd_channel(scmd));
888 spin_unlock_irqrestore(host->host_lock, flags);
889 }
890
891 return rtn;
892}
893
894static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
895{
896 sdev->was_reset = 1;
897 sdev->expecting_cc_ua = 1;
898}
899
900/**
901 * scsi_try_target_reset - Ask host to perform a target reset
902 * @scmd: SCSI cmd used to send a target reset
903 *
904 * Notes:
905 * There is no timeout for this operation. if this operation is
906 * unreliable for a given host, then the host itself needs to put a
907 * timer on it, and set the host back to a consistent state prior to
908 * returning.
909 */
910static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
911{
912 unsigned long flags;
913 enum scsi_disposition rtn;
914 struct Scsi_Host *host = scmd->device->host;
915 struct scsi_host_template *hostt = host->hostt;
916
917 if (!hostt->eh_target_reset_handler)
918 return FAILED;
919
920 rtn = hostt->eh_target_reset_handler(scmd);
921 if (rtn == SUCCESS) {
922 spin_lock_irqsave(host->host_lock, flags);
923 __starget_for_each_device(scsi_target(scmd->device), NULL,
924 __scsi_report_device_reset);
925 spin_unlock_irqrestore(host->host_lock, flags);
926 }
927
928 return rtn;
929}
930
931/**
932 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
933 * @scmd: SCSI cmd used to send BDR
934 *
935 * Notes:
936 * There is no timeout for this operation. if this operation is
937 * unreliable for a given host, then the host itself needs to put a
938 * timer on it, and set the host back to a consistent state prior to
939 * returning.
940 */
941static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
942{
943 enum scsi_disposition rtn;
944 struct scsi_host_template *hostt = scmd->device->host->hostt;
945
946 if (!hostt->eh_device_reset_handler)
947 return FAILED;
948
949 rtn = hostt->eh_device_reset_handler(scmd);
950 if (rtn == SUCCESS)
951 __scsi_report_device_reset(scmd->device, NULL);
952 return rtn;
953}
954
955/**
956 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
957 * @hostt: SCSI driver host template
958 * @scmd: SCSI cmd used to send a target reset
959 *
960 * Return value:
961 * SUCCESS, FAILED, or FAST_IO_FAIL
962 *
963 * Notes:
964 * SUCCESS does not necessarily indicate that the command
965 * has been aborted; it only indicates that the LLDDs
966 * has cleared all references to that command.
967 * LLDDs should return FAILED only if an abort was required
968 * but could not be executed. LLDDs should return FAST_IO_FAIL
969 * if the device is temporarily unavailable (eg due to a
970 * link down on FibreChannel)
971 */
972static enum scsi_disposition
973scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
974{
975 if (!hostt->eh_abort_handler)
976 return FAILED;
977
978 return hostt->eh_abort_handler(scmd);
979}
980
981static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
982{
983 if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
984 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
985 if (scsi_try_target_reset(scmd) != SUCCESS)
986 if (scsi_try_bus_reset(scmd) != SUCCESS)
987 scsi_try_host_reset(scmd);
988}
989
990/**
991 * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
992 * @scmd: SCSI command structure to hijack
993 * @ses: structure to save restore information
994 * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
995 * @cmnd_size: size in bytes of @cmnd (must be <= MAX_COMMAND_SIZE)
996 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
997 *
998 * This function is used to save a scsi command information before re-execution
999 * as part of the error recovery process. If @sense_bytes is 0 the command
1000 * sent must be one that does not transfer any data. If @sense_bytes != 0
1001 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
1002 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
1003 */
1004void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
1005 unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
1006{
1007 struct scsi_device *sdev = scmd->device;
1008
1009 /*
1010 * We need saved copies of a number of fields - this is because
1011 * error handling may need to overwrite these with different values
1012 * to run different commands, and once error handling is complete,
1013 * we will need to restore these values prior to running the actual
1014 * command.
1015 */
1016 ses->cmd_len = scmd->cmd_len;
1017 ses->data_direction = scmd->sc_data_direction;
1018 ses->sdb = scmd->sdb;
1019 ses->result = scmd->result;
1020 ses->resid_len = scmd->resid_len;
1021 ses->underflow = scmd->underflow;
1022 ses->prot_op = scmd->prot_op;
1023 ses->eh_eflags = scmd->eh_eflags;
1024
1025 scmd->prot_op = SCSI_PROT_NORMAL;
1026 scmd->eh_eflags = 0;
1027 memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd));
1028 memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
1029 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1030 scmd->result = 0;
1031 scmd->resid_len = 0;
1032
1033 if (sense_bytes) {
1034 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
1035 sense_bytes);
1036 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1037 scmd->sdb.length);
1038 scmd->sdb.table.sgl = &ses->sense_sgl;
1039 scmd->sc_data_direction = DMA_FROM_DEVICE;
1040 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1041 scmd->cmnd[0] = REQUEST_SENSE;
1042 scmd->cmnd[4] = scmd->sdb.length;
1043 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1044 } else {
1045 scmd->sc_data_direction = DMA_NONE;
1046 if (cmnd) {
1047 BUG_ON(cmnd_size > sizeof(scmd->cmnd));
1048 memcpy(scmd->cmnd, cmnd, cmnd_size);
1049 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1050 }
1051 }
1052
1053 scmd->underflow = 0;
1054
1055 if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1056 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1057 (sdev->lun << 5 & 0xe0);
1058
1059 /*
1060 * Zero the sense buffer. The scsi spec mandates that any
1061 * untransferred sense data should be interpreted as being zero.
1062 */
1063 memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1064}
1065EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1066
1067/**
1068 * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
1069 * @scmd: SCSI command structure to restore
1070 * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
1071 *
1072 * Undo any damage done by above scsi_eh_prep_cmnd().
1073 */
1074void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1075{
1076 /*
1077 * Restore original data
1078 */
1079 scmd->cmd_len = ses->cmd_len;
1080 memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd));
1081 scmd->sc_data_direction = ses->data_direction;
1082 scmd->sdb = ses->sdb;
1083 scmd->result = ses->result;
1084 scmd->resid_len = ses->resid_len;
1085 scmd->underflow = ses->underflow;
1086 scmd->prot_op = ses->prot_op;
1087 scmd->eh_eflags = ses->eh_eflags;
1088}
1089EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1090
1091/**
1092 * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
1093 * @scmd: SCSI command structure to hijack
1094 * @cmnd: CDB to send
1095 * @cmnd_size: size in bytes of @cmnd
1096 * @timeout: timeout for this request
1097 * @sense_bytes: size of sense data to copy or 0
1098 *
1099 * This function is used to send a scsi command down to a target device
1100 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1101 *
1102 * Return value:
1103 * SUCCESS or FAILED or NEEDS_RETRY
1104 */
1105static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1106 unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1107{
1108 struct scsi_device *sdev = scmd->device;
1109 struct Scsi_Host *shost = sdev->host;
1110 DECLARE_COMPLETION_ONSTACK(done);
1111 unsigned long timeleft = timeout, delay;
1112 struct scsi_eh_save ses;
1113 const unsigned long stall_for = msecs_to_jiffies(100);
1114 int rtn;
1115
1116retry:
1117 scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1118 shost->eh_action = &done;
1119
1120 scsi_log_send(scmd);
1121 scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
1122
1123 /*
1124 * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1125 * change the SCSI device state after we have examined it and before
1126 * .queuecommand() is called.
1127 */
1128 mutex_lock(&sdev->state_mutex);
1129 while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1130 mutex_unlock(&sdev->state_mutex);
1131 SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1132 "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1133 SDEV_BLOCK));
1134 delay = min(timeleft, stall_for);
1135 timeleft -= delay;
1136 msleep(jiffies_to_msecs(delay));
1137 mutex_lock(&sdev->state_mutex);
1138 }
1139 if (sdev->sdev_state != SDEV_BLOCK)
1140 rtn = shost->hostt->queuecommand(shost, scmd);
1141 else
1142 rtn = FAILED;
1143 mutex_unlock(&sdev->state_mutex);
1144
1145 if (rtn) {
1146 if (timeleft > stall_for) {
1147 scsi_eh_restore_cmnd(scmd, &ses);
1148
1149 timeleft -= stall_for;
1150 msleep(jiffies_to_msecs(stall_for));
1151 goto retry;
1152 }
1153 /* signal not to enter either branch of the if () below */
1154 timeleft = 0;
1155 rtn = FAILED;
1156 } else {
1157 timeleft = wait_for_completion_timeout(&done, timeout);
1158 rtn = SUCCESS;
1159 }
1160
1161 shost->eh_action = NULL;
1162
1163 scsi_log_completion(scmd, rtn);
1164
1165 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1166 "%s timeleft: %ld\n",
1167 __func__, timeleft));
1168
1169 /*
1170 * If there is time left scsi_eh_done got called, and we will examine
1171 * the actual status codes to see whether the command actually did
1172 * complete normally, else if we have a zero return and no time left,
1173 * the command must still be pending, so abort it and return FAILED.
1174 * If we never actually managed to issue the command, because
1175 * ->queuecommand() kept returning non zero, use the rtn = FAILED
1176 * value above (so don't execute either branch of the if)
1177 */
1178 if (timeleft) {
1179 rtn = scsi_eh_completed_normally(scmd);
1180 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1181 "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1182
1183 switch (rtn) {
1184 case SUCCESS:
1185 case NEEDS_RETRY:
1186 case FAILED:
1187 break;
1188 case ADD_TO_MLQUEUE:
1189 rtn = NEEDS_RETRY;
1190 break;
1191 default:
1192 rtn = FAILED;
1193 break;
1194 }
1195 } else if (rtn != FAILED) {
1196 scsi_abort_eh_cmnd(scmd);
1197 rtn = FAILED;
1198 }
1199
1200 scsi_eh_restore_cmnd(scmd, &ses);
1201
1202 return rtn;
1203}
1204
1205/**
1206 * scsi_request_sense - Request sense data from a particular target.
1207 * @scmd: SCSI cmd for request sense.
1208 *
1209 * Notes:
1210 * Some hosts automatically obtain this information, others require
1211 * that we obtain it on our own. This function will *not* return until
1212 * the command either times out, or it completes.
1213 */
1214static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1215{
1216 return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1217}
1218
1219static enum scsi_disposition
1220scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1221{
1222 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
1223 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1224 if (sdrv->eh_action)
1225 rtn = sdrv->eh_action(scmd, rtn);
1226 }
1227 return rtn;
1228}
1229
1230/**
1231 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1232 * @scmd: Original SCSI cmd that eh has finished.
1233 * @done_q: Queue for processed commands.
1234 *
1235 * Notes:
1236 * We don't want to use the normal command completion while we are are
1237 * still handling errors - it may cause other commands to be queued,
1238 * and that would disturb what we are doing. Thus we really want to
1239 * keep a list of pending commands for final completion, and once we
1240 * are ready to leave error handling we handle completion for real.
1241 */
1242void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1243{
1244 list_move_tail(&scmd->eh_entry, done_q);
1245}
1246EXPORT_SYMBOL(scsi_eh_finish_cmd);
1247
1248/**
1249 * scsi_eh_get_sense - Get device sense data.
1250 * @work_q: Queue of commands to process.
1251 * @done_q: Queue of processed commands.
1252 *
1253 * Description:
1254 * See if we need to request sense information. if so, then get it
1255 * now, so we have a better idea of what to do.
1256 *
1257 * Notes:
1258 * This has the unfortunate side effect that if a shost adapter does
1259 * not automatically request sense information, we end up shutting
1260 * it down before we request it.
1261 *
1262 * All drivers should request sense information internally these days,
1263 * so for now all I have to say is tough noogies if you end up in here.
1264 *
1265 * XXX: Long term this code should go away, but that needs an audit of
1266 * all LLDDs first.
1267 */
1268int scsi_eh_get_sense(struct list_head *work_q,
1269 struct list_head *done_q)
1270{
1271 struct scsi_cmnd *scmd, *next;
1272 struct Scsi_Host *shost;
1273 enum scsi_disposition rtn;
1274
1275 /*
1276 * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1277 * should not get sense.
1278 */
1279 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1280 if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1281 SCSI_SENSE_VALID(scmd))
1282 continue;
1283
1284 shost = scmd->device->host;
1285 if (scsi_host_eh_past_deadline(shost)) {
1286 SCSI_LOG_ERROR_RECOVERY(3,
1287 scmd_printk(KERN_INFO, scmd,
1288 "%s: skip request sense, past eh deadline\n",
1289 current->comm));
1290 break;
1291 }
1292 if (!scsi_status_is_check_condition(scmd->result))
1293 /*
1294 * don't request sense if there's no check condition
1295 * status because the error we're processing isn't one
1296 * that has a sense code (and some devices get
1297 * confused by sense requests out of the blue)
1298 */
1299 continue;
1300
1301 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1302 "%s: requesting sense\n",
1303 current->comm));
1304 rtn = scsi_request_sense(scmd);
1305 if (rtn != SUCCESS)
1306 continue;
1307
1308 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1309 "sense requested, result %x\n", scmd->result));
1310 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1311
1312 rtn = scsi_decide_disposition(scmd);
1313
1314 /*
1315 * if the result was normal, then just pass it along to the
1316 * upper level.
1317 */
1318 if (rtn == SUCCESS)
1319 /*
1320 * We don't want this command reissued, just finished
1321 * with the sense data, so set retries to the max
1322 * allowed to ensure it won't get reissued. If the user
1323 * has requested infinite retries, we also want to
1324 * finish this command, so force completion by setting
1325 * retries and allowed to the same value.
1326 */
1327 if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1328 scmd->retries = scmd->allowed = 1;
1329 else
1330 scmd->retries = scmd->allowed;
1331 else if (rtn != NEEDS_RETRY)
1332 continue;
1333
1334 scsi_eh_finish_cmd(scmd, done_q);
1335 }
1336
1337 return list_empty(work_q);
1338}
1339EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1340
1341/**
1342 * scsi_eh_tur - Send TUR to device.
1343 * @scmd: &scsi_cmnd to send TUR
1344 *
1345 * Return value:
1346 * 0 - Device is ready. 1 - Device NOT ready.
1347 */
1348static int scsi_eh_tur(struct scsi_cmnd *scmd)
1349{
1350 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1351 int retry_cnt = 1;
1352 enum scsi_disposition rtn;
1353
1354retry_tur:
1355 rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1356 scmd->device->eh_timeout, 0);
1357
1358 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1359 "%s return: %x\n", __func__, rtn));
1360
1361 switch (rtn) {
1362 case NEEDS_RETRY:
1363 if (retry_cnt--)
1364 goto retry_tur;
1365 fallthrough;
1366 case SUCCESS:
1367 return 0;
1368 default:
1369 return 1;
1370 }
1371}
1372
1373/**
1374 * scsi_eh_test_devices - check if devices are responding from error recovery.
1375 * @cmd_list: scsi commands in error recovery.
1376 * @work_q: queue for commands which still need more error recovery
1377 * @done_q: queue for commands which are finished
1378 * @try_stu: boolean on if a STU command should be tried in addition to TUR.
1379 *
1380 * Decription:
1381 * Tests if devices are in a working state. Commands to devices now in
1382 * a working state are sent to the done_q while commands to devices which
1383 * are still failing to respond are returned to the work_q for more
1384 * processing.
1385 **/
1386static int scsi_eh_test_devices(struct list_head *cmd_list,
1387 struct list_head *work_q,
1388 struct list_head *done_q, int try_stu)
1389{
1390 struct scsi_cmnd *scmd, *next;
1391 struct scsi_device *sdev;
1392 int finish_cmds;
1393
1394 while (!list_empty(cmd_list)) {
1395 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1396 sdev = scmd->device;
1397
1398 if (!try_stu) {
1399 if (scsi_host_eh_past_deadline(sdev->host)) {
1400 /* Push items back onto work_q */
1401 list_splice_init(cmd_list, work_q);
1402 SCSI_LOG_ERROR_RECOVERY(3,
1403 sdev_printk(KERN_INFO, sdev,
1404 "%s: skip test device, past eh deadline",
1405 current->comm));
1406 break;
1407 }
1408 }
1409
1410 finish_cmds = !scsi_device_online(scmd->device) ||
1411 (try_stu && !scsi_eh_try_stu(scmd) &&
1412 !scsi_eh_tur(scmd)) ||
1413 !scsi_eh_tur(scmd);
1414
1415 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1416 if (scmd->device == sdev) {
1417 if (finish_cmds &&
1418 (try_stu ||
1419 scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1420 scsi_eh_finish_cmd(scmd, done_q);
1421 else
1422 list_move_tail(&scmd->eh_entry, work_q);
1423 }
1424 }
1425 return list_empty(work_q);
1426}
1427
1428/**
1429 * scsi_eh_try_stu - Send START_UNIT to device.
1430 * @scmd: &scsi_cmnd to send START_UNIT
1431 *
1432 * Return value:
1433 * 0 - Device is ready. 1 - Device NOT ready.
1434 */
1435static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1436{
1437 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1438
1439 if (scmd->device->allow_restart) {
1440 int i;
1441 enum scsi_disposition rtn = NEEDS_RETRY;
1442
1443 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1444 rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
1445 scmd->device->eh_timeout, 0);
1446
1447 if (rtn == SUCCESS)
1448 return 0;
1449 }
1450
1451 return 1;
1452}
1453
1454 /**
1455 * scsi_eh_stu - send START_UNIT if needed
1456 * @shost: &scsi host being recovered.
1457 * @work_q: &list_head for pending commands.
1458 * @done_q: &list_head for processed commands.
1459 *
1460 * Notes:
1461 * If commands are failing due to not ready, initializing command required,
1462 * try revalidating the device, which will end up sending a start unit.
1463 */
1464static int scsi_eh_stu(struct Scsi_Host *shost,
1465 struct list_head *work_q,
1466 struct list_head *done_q)
1467{
1468 struct scsi_cmnd *scmd, *stu_scmd, *next;
1469 struct scsi_device *sdev;
1470
1471 shost_for_each_device(sdev, shost) {
1472 if (scsi_host_eh_past_deadline(shost)) {
1473 SCSI_LOG_ERROR_RECOVERY(3,
1474 sdev_printk(KERN_INFO, sdev,
1475 "%s: skip START_UNIT, past eh deadline\n",
1476 current->comm));
1477 scsi_device_put(sdev);
1478 break;
1479 }
1480 stu_scmd = NULL;
1481 list_for_each_entry(scmd, work_q, eh_entry)
1482 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1483 scsi_check_sense(scmd) == FAILED ) {
1484 stu_scmd = scmd;
1485 break;
1486 }
1487
1488 if (!stu_scmd)
1489 continue;
1490
1491 SCSI_LOG_ERROR_RECOVERY(3,
1492 sdev_printk(KERN_INFO, sdev,
1493 "%s: Sending START_UNIT\n",
1494 current->comm));
1495
1496 if (!scsi_eh_try_stu(stu_scmd)) {
1497 if (!scsi_device_online(sdev) ||
1498 !scsi_eh_tur(stu_scmd)) {
1499 list_for_each_entry_safe(scmd, next,
1500 work_q, eh_entry) {
1501 if (scmd->device == sdev &&
1502 scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1503 scsi_eh_finish_cmd(scmd, done_q);
1504 }
1505 }
1506 } else {
1507 SCSI_LOG_ERROR_RECOVERY(3,
1508 sdev_printk(KERN_INFO, sdev,
1509 "%s: START_UNIT failed\n",
1510 current->comm));
1511 }
1512 }
1513
1514 return list_empty(work_q);
1515}
1516
1517
1518/**
1519 * scsi_eh_bus_device_reset - send bdr if needed
1520 * @shost: scsi host being recovered.
1521 * @work_q: &list_head for pending commands.
1522 * @done_q: &list_head for processed commands.
1523 *
1524 * Notes:
1525 * Try a bus device reset. Still, look to see whether we have multiple
1526 * devices that are jammed or not - if we have multiple devices, it
1527 * makes no sense to try bus_device_reset - we really would need to try
1528 * a bus_reset instead.
1529 */
1530static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1531 struct list_head *work_q,
1532 struct list_head *done_q)
1533{
1534 struct scsi_cmnd *scmd, *bdr_scmd, *next;
1535 struct scsi_device *sdev;
1536 enum scsi_disposition rtn;
1537
1538 shost_for_each_device(sdev, shost) {
1539 if (scsi_host_eh_past_deadline(shost)) {
1540 SCSI_LOG_ERROR_RECOVERY(3,
1541 sdev_printk(KERN_INFO, sdev,
1542 "%s: skip BDR, past eh deadline\n",
1543 current->comm));
1544 scsi_device_put(sdev);
1545 break;
1546 }
1547 bdr_scmd = NULL;
1548 list_for_each_entry(scmd, work_q, eh_entry)
1549 if (scmd->device == sdev) {
1550 bdr_scmd = scmd;
1551 break;
1552 }
1553
1554 if (!bdr_scmd)
1555 continue;
1556
1557 SCSI_LOG_ERROR_RECOVERY(3,
1558 sdev_printk(KERN_INFO, sdev,
1559 "%s: Sending BDR\n", current->comm));
1560 rtn = scsi_try_bus_device_reset(bdr_scmd);
1561 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1562 if (!scsi_device_online(sdev) ||
1563 rtn == FAST_IO_FAIL ||
1564 !scsi_eh_tur(bdr_scmd)) {
1565 list_for_each_entry_safe(scmd, next,
1566 work_q, eh_entry) {
1567 if (scmd->device == sdev &&
1568 scsi_eh_action(scmd, rtn) != FAILED)
1569 scsi_eh_finish_cmd(scmd,
1570 done_q);
1571 }
1572 }
1573 } else {
1574 SCSI_LOG_ERROR_RECOVERY(3,
1575 sdev_printk(KERN_INFO, sdev,
1576 "%s: BDR failed\n", current->comm));
1577 }
1578 }
1579
1580 return list_empty(work_q);
1581}
1582
1583/**
1584 * scsi_eh_target_reset - send target reset if needed
1585 * @shost: scsi host being recovered.
1586 * @work_q: &list_head for pending commands.
1587 * @done_q: &list_head for processed commands.
1588 *
1589 * Notes:
1590 * Try a target reset.
1591 */
1592static int scsi_eh_target_reset(struct Scsi_Host *shost,
1593 struct list_head *work_q,
1594 struct list_head *done_q)
1595{
1596 LIST_HEAD(tmp_list);
1597 LIST_HEAD(check_list);
1598
1599 list_splice_init(work_q, &tmp_list);
1600
1601 while (!list_empty(&tmp_list)) {
1602 struct scsi_cmnd *next, *scmd;
1603 enum scsi_disposition rtn;
1604 unsigned int id;
1605
1606 if (scsi_host_eh_past_deadline(shost)) {
1607 /* push back on work queue for further processing */
1608 list_splice_init(&check_list, work_q);
1609 list_splice_init(&tmp_list, work_q);
1610 SCSI_LOG_ERROR_RECOVERY(3,
1611 shost_printk(KERN_INFO, shost,
1612 "%s: Skip target reset, past eh deadline\n",
1613 current->comm));
1614 return list_empty(work_q);
1615 }
1616
1617 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1618 id = scmd_id(scmd);
1619
1620 SCSI_LOG_ERROR_RECOVERY(3,
1621 shost_printk(KERN_INFO, shost,
1622 "%s: Sending target reset to target %d\n",
1623 current->comm, id));
1624 rtn = scsi_try_target_reset(scmd);
1625 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1626 SCSI_LOG_ERROR_RECOVERY(3,
1627 shost_printk(KERN_INFO, shost,
1628 "%s: Target reset failed"
1629 " target: %d\n",
1630 current->comm, id));
1631 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1632 if (scmd_id(scmd) != id)
1633 continue;
1634
1635 if (rtn == SUCCESS)
1636 list_move_tail(&scmd->eh_entry, &check_list);
1637 else if (rtn == FAST_IO_FAIL)
1638 scsi_eh_finish_cmd(scmd, done_q);
1639 else
1640 /* push back on work queue for further processing */
1641 list_move(&scmd->eh_entry, work_q);
1642 }
1643 }
1644
1645 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1646}
1647
1648/**
1649 * scsi_eh_bus_reset - send a bus reset
1650 * @shost: &scsi host being recovered.
1651 * @work_q: &list_head for pending commands.
1652 * @done_q: &list_head for processed commands.
1653 */
1654static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1655 struct list_head *work_q,
1656 struct list_head *done_q)
1657{
1658 struct scsi_cmnd *scmd, *chan_scmd, *next;
1659 LIST_HEAD(check_list);
1660 unsigned int channel;
1661 enum scsi_disposition rtn;
1662
1663 /*
1664 * we really want to loop over the various channels, and do this on
1665 * a channel by channel basis. we should also check to see if any
1666 * of the failed commands are on soft_reset devices, and if so, skip
1667 * the reset.
1668 */
1669
1670 for (channel = 0; channel <= shost->max_channel; channel++) {
1671 if (scsi_host_eh_past_deadline(shost)) {
1672 list_splice_init(&check_list, work_q);
1673 SCSI_LOG_ERROR_RECOVERY(3,
1674 shost_printk(KERN_INFO, shost,
1675 "%s: skip BRST, past eh deadline\n",
1676 current->comm));
1677 return list_empty(work_q);
1678 }
1679
1680 chan_scmd = NULL;
1681 list_for_each_entry(scmd, work_q, eh_entry) {
1682 if (channel == scmd_channel(scmd)) {
1683 chan_scmd = scmd;
1684 break;
1685 /*
1686 * FIXME add back in some support for
1687 * soft_reset devices.
1688 */
1689 }
1690 }
1691
1692 if (!chan_scmd)
1693 continue;
1694 SCSI_LOG_ERROR_RECOVERY(3,
1695 shost_printk(KERN_INFO, shost,
1696 "%s: Sending BRST chan: %d\n",
1697 current->comm, channel));
1698 rtn = scsi_try_bus_reset(chan_scmd);
1699 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1700 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1701 if (channel == scmd_channel(scmd)) {
1702 if (rtn == FAST_IO_FAIL)
1703 scsi_eh_finish_cmd(scmd,
1704 done_q);
1705 else
1706 list_move_tail(&scmd->eh_entry,
1707 &check_list);
1708 }
1709 }
1710 } else {
1711 SCSI_LOG_ERROR_RECOVERY(3,
1712 shost_printk(KERN_INFO, shost,
1713 "%s: BRST failed chan: %d\n",
1714 current->comm, channel));
1715 }
1716 }
1717 return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1718}
1719
1720/**
1721 * scsi_eh_host_reset - send a host reset
1722 * @shost: host to be reset.
1723 * @work_q: &list_head for pending commands.
1724 * @done_q: &list_head for processed commands.
1725 */
1726static int scsi_eh_host_reset(struct Scsi_Host *shost,
1727 struct list_head *work_q,
1728 struct list_head *done_q)
1729{
1730 struct scsi_cmnd *scmd, *next;
1731 LIST_HEAD(check_list);
1732 enum scsi_disposition rtn;
1733
1734 if (!list_empty(work_q)) {
1735 scmd = list_entry(work_q->next,
1736 struct scsi_cmnd, eh_entry);
1737
1738 SCSI_LOG_ERROR_RECOVERY(3,
1739 shost_printk(KERN_INFO, shost,
1740 "%s: Sending HRST\n",
1741 current->comm));
1742
1743 rtn = scsi_try_host_reset(scmd);
1744 if (rtn == SUCCESS) {
1745 list_splice_init(work_q, &check_list);
1746 } else if (rtn == FAST_IO_FAIL) {
1747 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1748 scsi_eh_finish_cmd(scmd, done_q);
1749 }
1750 } else {
1751 SCSI_LOG_ERROR_RECOVERY(3,
1752 shost_printk(KERN_INFO, shost,
1753 "%s: HRST failed\n",
1754 current->comm));
1755 }
1756 }
1757 return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1758}
1759
1760/**
1761 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1762 * @work_q: &list_head for pending commands.
1763 * @done_q: &list_head for processed commands.
1764 */
1765static void scsi_eh_offline_sdevs(struct list_head *work_q,
1766 struct list_head *done_q)
1767{
1768 struct scsi_cmnd *scmd, *next;
1769 struct scsi_device *sdev;
1770
1771 list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1772 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1773 "not ready after error recovery\n");
1774 sdev = scmd->device;
1775
1776 mutex_lock(&sdev->state_mutex);
1777 scsi_device_set_state(sdev, SDEV_OFFLINE);
1778 mutex_unlock(&sdev->state_mutex);
1779
1780 scsi_eh_finish_cmd(scmd, done_q);
1781 }
1782 return;
1783}
1784
1785/**
1786 * scsi_noretry_cmd - determine if command should be failed fast
1787 * @scmd: SCSI cmd to examine.
1788 */
1789bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
1790{
1791 struct request *req = scsi_cmd_to_rq(scmd);
1792
1793 switch (host_byte(scmd->result)) {
1794 case DID_OK:
1795 break;
1796 case DID_TIME_OUT:
1797 goto check_type;
1798 case DID_BUS_BUSY:
1799 return !!(req->cmd_flags & REQ_FAILFAST_TRANSPORT);
1800 case DID_PARITY:
1801 return !!(req->cmd_flags & REQ_FAILFAST_DEV);
1802 case DID_ERROR:
1803 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1804 return false;
1805 fallthrough;
1806 case DID_SOFT_ERROR:
1807 return !!(req->cmd_flags & REQ_FAILFAST_DRIVER);
1808 }
1809
1810 if (!scsi_status_is_check_condition(scmd->result))
1811 return false;
1812
1813check_type:
1814 /*
1815 * assume caller has checked sense and determined
1816 * the check condition was retryable.
1817 */
1818 if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(req))
1819 return true;
1820
1821 return false;
1822}
1823
1824/**
1825 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1826 * @scmd: SCSI cmd to examine.
1827 *
1828 * Notes:
1829 * This is *only* called when we are examining the status after sending
1830 * out the actual data command. any commands that are queued for error
1831 * recovery (e.g. test_unit_ready) do *not* come through here.
1832 *
1833 * When this routine returns failed, it means the error handler thread
1834 * is woken. In cases where the error code indicates an error that
1835 * doesn't require the error handler read (i.e. we don't need to
1836 * abort/reset), this function should return SUCCESS.
1837 */
1838enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1839{
1840 enum scsi_disposition rtn;
1841
1842 /*
1843 * if the device is offline, then we clearly just pass the result back
1844 * up to the top level.
1845 */
1846 if (!scsi_device_online(scmd->device)) {
1847 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1848 "%s: device offline - report as SUCCESS\n", __func__));
1849 return SUCCESS;
1850 }
1851
1852 /*
1853 * first check the host byte, to see if there is anything in there
1854 * that would indicate what we need to do.
1855 */
1856 switch (host_byte(scmd->result)) {
1857 case DID_PASSTHROUGH:
1858 /*
1859 * no matter what, pass this through to the upper layer.
1860 * nuke this special code so that it looks like we are saying
1861 * did_ok.
1862 */
1863 scmd->result &= 0xff00ffff;
1864 return SUCCESS;
1865 case DID_OK:
1866 /*
1867 * looks good. drop through, and check the next byte.
1868 */
1869 break;
1870 case DID_ABORT:
1871 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1872 set_host_byte(scmd, DID_TIME_OUT);
1873 return SUCCESS;
1874 }
1875 fallthrough;
1876 case DID_NO_CONNECT:
1877 case DID_BAD_TARGET:
1878 /*
1879 * note - this means that we just report the status back
1880 * to the top level driver, not that we actually think
1881 * that it indicates SUCCESS.
1882 */
1883 return SUCCESS;
1884 case DID_SOFT_ERROR:
1885 /*
1886 * when the low level driver returns did_soft_error,
1887 * it is responsible for keeping an internal retry counter
1888 * in order to avoid endless loops (db)
1889 */
1890 goto maybe_retry;
1891 case DID_IMM_RETRY:
1892 return NEEDS_RETRY;
1893
1894 case DID_REQUEUE:
1895 return ADD_TO_MLQUEUE;
1896 case DID_TRANSPORT_DISRUPTED:
1897 /*
1898 * LLD/transport was disrupted during processing of the IO.
1899 * The transport class is now blocked/blocking,
1900 * and the transport will decide what to do with the IO
1901 * based on its timers and recovery capablilities if
1902 * there are enough retries.
1903 */
1904 goto maybe_retry;
1905 case DID_TRANSPORT_FAILFAST:
1906 /*
1907 * The transport decided to failfast the IO (most likely
1908 * the fast io fail tmo fired), so send IO directly upwards.
1909 */
1910 return SUCCESS;
1911 case DID_TRANSPORT_MARGINAL:
1912 /*
1913 * caller has decided not to do retries on
1914 * abort success, so send IO directly upwards
1915 */
1916 return SUCCESS;
1917 case DID_ERROR:
1918 if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
1919 /*
1920 * execute reservation conflict processing code
1921 * lower down
1922 */
1923 break;
1924 fallthrough;
1925 case DID_BUS_BUSY:
1926 case DID_PARITY:
1927 goto maybe_retry;
1928 case DID_TIME_OUT:
1929 /*
1930 * when we scan the bus, we get timeout messages for
1931 * these commands if there is no device available.
1932 * other hosts report did_no_connect for the same thing.
1933 */
1934 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1935 scmd->cmnd[0] == INQUIRY)) {
1936 return SUCCESS;
1937 } else {
1938 return FAILED;
1939 }
1940 case DID_RESET:
1941 return SUCCESS;
1942 default:
1943 return FAILED;
1944 }
1945
1946 /*
1947 * check the status byte to see if this indicates anything special.
1948 */
1949 switch (get_status_byte(scmd)) {
1950 case SAM_STAT_TASK_SET_FULL:
1951 scsi_handle_queue_full(scmd->device);
1952 /*
1953 * the case of trying to send too many commands to a
1954 * tagged queueing device.
1955 */
1956 fallthrough;
1957 case SAM_STAT_BUSY:
1958 /*
1959 * device can't talk to us at the moment. Should only
1960 * occur (SAM-3) when the task queue is empty, so will cause
1961 * the empty queue handling to trigger a stall in the
1962 * device.
1963 */
1964 return ADD_TO_MLQUEUE;
1965 case SAM_STAT_GOOD:
1966 if (scmd->cmnd[0] == REPORT_LUNS)
1967 scmd->device->sdev_target->expecting_lun_change = 0;
1968 scsi_handle_queue_ramp_up(scmd->device);
1969 fallthrough;
1970 case SAM_STAT_COMMAND_TERMINATED:
1971 return SUCCESS;
1972 case SAM_STAT_TASK_ABORTED:
1973 goto maybe_retry;
1974 case SAM_STAT_CHECK_CONDITION:
1975 rtn = scsi_check_sense(scmd);
1976 if (rtn == NEEDS_RETRY)
1977 goto maybe_retry;
1978 /* if rtn == FAILED, we have no sense information;
1979 * returning FAILED will wake the error handler thread
1980 * to collect the sense and redo the decide
1981 * disposition */
1982 return rtn;
1983 case SAM_STAT_CONDITION_MET:
1984 case SAM_STAT_INTERMEDIATE:
1985 case SAM_STAT_INTERMEDIATE_CONDITION_MET:
1986 case SAM_STAT_ACA_ACTIVE:
1987 /*
1988 * who knows? FIXME(eric)
1989 */
1990 return SUCCESS;
1991
1992 case SAM_STAT_RESERVATION_CONFLICT:
1993 sdev_printk(KERN_INFO, scmd->device,
1994 "reservation conflict\n");
1995 set_scsi_ml_byte(scmd, SCSIML_STAT_RESV_CONFLICT);
1996 return SUCCESS; /* causes immediate i/o error */
1997 }
1998 return FAILED;
1999
2000maybe_retry:
2001
2002 /* we requeue for retry because the error was retryable, and
2003 * the request was not marked fast fail. Note that above,
2004 * even if the request is marked fast fail, we still requeue
2005 * for queue congestion conditions (QUEUE_FULL or BUSY) */
2006 if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
2007 return NEEDS_RETRY;
2008 } else {
2009 /*
2010 * no more retries - report this one back to upper level.
2011 */
2012 return SUCCESS;
2013 }
2014}
2015
2016static enum rq_end_io_ret eh_lock_door_done(struct request *req,
2017 blk_status_t status)
2018{
2019 blk_mq_free_request(req);
2020 return RQ_END_IO_NONE;
2021}
2022
2023/**
2024 * scsi_eh_lock_door - Prevent medium removal for the specified device
2025 * @sdev: SCSI device to prevent medium removal
2026 *
2027 * Locking:
2028 * We must be called from process context.
2029 *
2030 * Notes:
2031 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
2032 * head of the devices request queue, and continue.
2033 */
2034static void scsi_eh_lock_door(struct scsi_device *sdev)
2035{
2036 struct scsi_cmnd *scmd;
2037 struct request *req;
2038
2039 req = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
2040 if (IS_ERR(req))
2041 return;
2042 scmd = blk_mq_rq_to_pdu(req);
2043
2044 scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL;
2045 scmd->cmnd[1] = 0;
2046 scmd->cmnd[2] = 0;
2047 scmd->cmnd[3] = 0;
2048 scmd->cmnd[4] = SCSI_REMOVAL_PREVENT;
2049 scmd->cmnd[5] = 0;
2050 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
2051 scmd->allowed = 5;
2052
2053 req->rq_flags |= RQF_QUIET;
2054 req->timeout = 10 * HZ;
2055 req->end_io = eh_lock_door_done;
2056
2057 blk_execute_rq_nowait(req, true);
2058}
2059
2060/**
2061 * scsi_restart_operations - restart io operations to the specified host.
2062 * @shost: Host we are restarting.
2063 *
2064 * Notes:
2065 * When we entered the error handler, we blocked all further i/o to
2066 * this device. we need to 'reverse' this process.
2067 */
2068static void scsi_restart_operations(struct Scsi_Host *shost)
2069{
2070 struct scsi_device *sdev;
2071 unsigned long flags;
2072
2073 /*
2074 * If the door was locked, we need to insert a door lock request
2075 * onto the head of the SCSI request queue for the device. There
2076 * is no point trying to lock the door of an off-line device.
2077 */
2078 shost_for_each_device(sdev, shost) {
2079 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2080 scsi_eh_lock_door(sdev);
2081 sdev->was_reset = 0;
2082 }
2083 }
2084
2085 /*
2086 * next free up anything directly waiting upon the host. this
2087 * will be requests for character device operations, and also for
2088 * ioctls to queued block devices.
2089 */
2090 SCSI_LOG_ERROR_RECOVERY(3,
2091 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2092
2093 spin_lock_irqsave(shost->host_lock, flags);
2094 if (scsi_host_set_state(shost, SHOST_RUNNING))
2095 if (scsi_host_set_state(shost, SHOST_CANCEL))
2096 BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2097 spin_unlock_irqrestore(shost->host_lock, flags);
2098
2099 wake_up(&shost->host_wait);
2100
2101 /*
2102 * finally we need to re-initiate requests that may be pending. we will
2103 * have had everything blocked while error handling is taking place, and
2104 * now that error recovery is done, we will need to ensure that these
2105 * requests are started.
2106 */
2107 scsi_run_host_queues(shost);
2108
2109 /*
2110 * if eh is active and host_eh_scheduled is pending we need to re-run
2111 * recovery. we do this check after scsi_run_host_queues() to allow
2112 * everything pent up since the last eh run a chance to make forward
2113 * progress before we sync again. Either we'll immediately re-run
2114 * recovery or scsi_device_unbusy() will wake us again when these
2115 * pending commands complete.
2116 */
2117 spin_lock_irqsave(shost->host_lock, flags);
2118 if (shost->host_eh_scheduled)
2119 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2120 WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2121 spin_unlock_irqrestore(shost->host_lock, flags);
2122}
2123
2124/**
2125 * scsi_eh_ready_devs - check device ready state and recover if not.
2126 * @shost: host to be recovered.
2127 * @work_q: &list_head for pending commands.
2128 * @done_q: &list_head for processed commands.
2129 */
2130void scsi_eh_ready_devs(struct Scsi_Host *shost,
2131 struct list_head *work_q,
2132 struct list_head *done_q)
2133{
2134 if (!scsi_eh_stu(shost, work_q, done_q))
2135 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2136 if (!scsi_eh_target_reset(shost, work_q, done_q))
2137 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2138 if (!scsi_eh_host_reset(shost, work_q, done_q))
2139 scsi_eh_offline_sdevs(work_q,
2140 done_q);
2141}
2142EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2143
2144/**
2145 * scsi_eh_flush_done_q - finish processed commands or retry them.
2146 * @done_q: list_head of processed commands.
2147 */
2148void scsi_eh_flush_done_q(struct list_head *done_q)
2149{
2150 struct scsi_cmnd *scmd, *next;
2151
2152 list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2153 list_del_init(&scmd->eh_entry);
2154 if (scsi_device_online(scmd->device) &&
2155 !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2156 scsi_eh_should_retry_cmd(scmd)) {
2157 SCSI_LOG_ERROR_RECOVERY(3,
2158 scmd_printk(KERN_INFO, scmd,
2159 "%s: flush retry cmd\n",
2160 current->comm));
2161 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2162 } else {
2163 /*
2164 * If just we got sense for the device (called
2165 * scsi_eh_get_sense), scmd->result is already
2166 * set, do not set DID_TIME_OUT.
2167 */
2168 if (!scmd->result)
2169 scmd->result |= (DID_TIME_OUT << 16);
2170 SCSI_LOG_ERROR_RECOVERY(3,
2171 scmd_printk(KERN_INFO, scmd,
2172 "%s: flush finish cmd\n",
2173 current->comm));
2174 scsi_finish_command(scmd);
2175 }
2176 }
2177}
2178EXPORT_SYMBOL(scsi_eh_flush_done_q);
2179
2180/**
2181 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2182 * @shost: Host to unjam.
2183 *
2184 * Notes:
2185 * When we come in here, we *know* that all commands on the bus have
2186 * either completed, failed or timed out. we also know that no further
2187 * commands are being sent to the host, so things are relatively quiet
2188 * and we have freedom to fiddle with things as we wish.
2189 *
2190 * This is only the *default* implementation. it is possible for
2191 * individual drivers to supply their own version of this function, and
2192 * if the maintainer wishes to do this, it is strongly suggested that
2193 * this function be taken as a template and modified. this function
2194 * was designed to correctly handle problems for about 95% of the
2195 * different cases out there, and it should always provide at least a
2196 * reasonable amount of error recovery.
2197 *
2198 * Any command marked 'failed' or 'timeout' must eventually have
2199 * scsi_finish_cmd() called for it. we do all of the retry stuff
2200 * here, so when we restart the host after we return it should have an
2201 * empty queue.
2202 */
2203static void scsi_unjam_host(struct Scsi_Host *shost)
2204{
2205 unsigned long flags;
2206 LIST_HEAD(eh_work_q);
2207 LIST_HEAD(eh_done_q);
2208
2209 spin_lock_irqsave(shost->host_lock, flags);
2210 list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2211 spin_unlock_irqrestore(shost->host_lock, flags);
2212
2213 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2214
2215 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2216 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2217
2218 spin_lock_irqsave(shost->host_lock, flags);
2219 if (shost->eh_deadline != -1)
2220 shost->last_reset = 0;
2221 spin_unlock_irqrestore(shost->host_lock, flags);
2222 scsi_eh_flush_done_q(&eh_done_q);
2223}
2224
2225/**
2226 * scsi_error_handler - SCSI error handler thread
2227 * @data: Host for which we are running.
2228 *
2229 * Notes:
2230 * This is the main error handling loop. This is run as a kernel thread
2231 * for every SCSI host and handles all error handling activity.
2232 */
2233int scsi_error_handler(void *data)
2234{
2235 struct Scsi_Host *shost = data;
2236
2237 /*
2238 * We use TASK_INTERRUPTIBLE so that the thread is not
2239 * counted against the load average as a running process.
2240 * We never actually get interrupted because kthread_run
2241 * disables signal delivery for the created thread.
2242 */
2243 while (true) {
2244 /*
2245 * The sequence in kthread_stop() sets the stop flag first
2246 * then wakes the process. To avoid missed wakeups, the task
2247 * should always be in a non running state before the stop
2248 * flag is checked
2249 */
2250 set_current_state(TASK_INTERRUPTIBLE);
2251 if (kthread_should_stop())
2252 break;
2253
2254 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2255 shost->host_failed != scsi_host_busy(shost)) {
2256 SCSI_LOG_ERROR_RECOVERY(1,
2257 shost_printk(KERN_INFO, shost,
2258 "scsi_eh_%d: sleeping\n",
2259 shost->host_no));
2260 schedule();
2261 continue;
2262 }
2263
2264 __set_current_state(TASK_RUNNING);
2265 SCSI_LOG_ERROR_RECOVERY(1,
2266 shost_printk(KERN_INFO, shost,
2267 "scsi_eh_%d: waking up %d/%d/%d\n",
2268 shost->host_no, shost->host_eh_scheduled,
2269 shost->host_failed,
2270 scsi_host_busy(shost)));
2271
2272 /*
2273 * We have a host that is failing for some reason. Figure out
2274 * what we need to do to get it up and online again (if we can).
2275 * If we fail, we end up taking the thing offline.
2276 */
2277 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2278 SCSI_LOG_ERROR_RECOVERY(1,
2279 shost_printk(KERN_ERR, shost,
2280 "scsi_eh_%d: unable to autoresume\n",
2281 shost->host_no));
2282 continue;
2283 }
2284
2285 if (shost->transportt->eh_strategy_handler)
2286 shost->transportt->eh_strategy_handler(shost);
2287 else
2288 scsi_unjam_host(shost);
2289
2290 /* All scmds have been handled */
2291 shost->host_failed = 0;
2292
2293 /*
2294 * Note - if the above fails completely, the action is to take
2295 * individual devices offline and flush the queue of any
2296 * outstanding requests that may have been pending. When we
2297 * restart, we restart any I/O to any other devices on the bus
2298 * which are still online.
2299 */
2300 scsi_restart_operations(shost);
2301 if (!shost->eh_noresume)
2302 scsi_autopm_put_host(shost);
2303 }
2304 __set_current_state(TASK_RUNNING);
2305
2306 SCSI_LOG_ERROR_RECOVERY(1,
2307 shost_printk(KERN_INFO, shost,
2308 "Error handler scsi_eh_%d exiting\n",
2309 shost->host_no));
2310 shost->ehandler = NULL;
2311 return 0;
2312}
2313
2314/*
2315 * Function: scsi_report_bus_reset()
2316 *
2317 * Purpose: Utility function used by low-level drivers to report that
2318 * they have observed a bus reset on the bus being handled.
2319 *
2320 * Arguments: shost - Host in question
2321 * channel - channel on which reset was observed.
2322 *
2323 * Returns: Nothing
2324 *
2325 * Lock status: Host lock must be held.
2326 *
2327 * Notes: This only needs to be called if the reset is one which
2328 * originates from an unknown location. Resets originated
2329 * by the mid-level itself don't need to call this, but there
2330 * should be no harm.
2331 *
2332 * The main purpose of this is to make sure that a CHECK_CONDITION
2333 * is properly treated.
2334 */
2335void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2336{
2337 struct scsi_device *sdev;
2338
2339 __shost_for_each_device(sdev, shost) {
2340 if (channel == sdev_channel(sdev))
2341 __scsi_report_device_reset(sdev, NULL);
2342 }
2343}
2344EXPORT_SYMBOL(scsi_report_bus_reset);
2345
2346/*
2347 * Function: scsi_report_device_reset()
2348 *
2349 * Purpose: Utility function used by low-level drivers to report that
2350 * they have observed a device reset on the device being handled.
2351 *
2352 * Arguments: shost - Host in question
2353 * channel - channel on which reset was observed
2354 * target - target on which reset was observed
2355 *
2356 * Returns: Nothing
2357 *
2358 * Lock status: Host lock must be held
2359 *
2360 * Notes: This only needs to be called if the reset is one which
2361 * originates from an unknown location. Resets originated
2362 * by the mid-level itself don't need to call this, but there
2363 * should be no harm.
2364 *
2365 * The main purpose of this is to make sure that a CHECK_CONDITION
2366 * is properly treated.
2367 */
2368void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2369{
2370 struct scsi_device *sdev;
2371
2372 __shost_for_each_device(sdev, shost) {
2373 if (channel == sdev_channel(sdev) &&
2374 target == sdev_id(sdev))
2375 __scsi_report_device_reset(sdev, NULL);
2376 }
2377}
2378EXPORT_SYMBOL(scsi_report_device_reset);
2379
2380/**
2381 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2382 * @dev: scsi_device to operate on
2383 * @arg: reset type (see sg.h)
2384 */
2385int
2386scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2387{
2388 struct scsi_cmnd *scmd;
2389 struct Scsi_Host *shost = dev->host;
2390 struct request *rq;
2391 unsigned long flags;
2392 int error = 0, val;
2393 enum scsi_disposition rtn;
2394
2395 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2396 return -EACCES;
2397
2398 error = get_user(val, arg);
2399 if (error)
2400 return error;
2401
2402 if (scsi_autopm_get_host(shost) < 0)
2403 return -EIO;
2404
2405 error = -EIO;
2406 rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2407 shost->hostt->cmd_size, GFP_KERNEL);
2408 if (!rq)
2409 goto out_put_autopm_host;
2410 blk_rq_init(NULL, rq);
2411
2412 scmd = (struct scsi_cmnd *)(rq + 1);
2413 scsi_init_command(dev, scmd);
2414
2415 scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
2416 memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2417
2418 scmd->cmd_len = 0;
2419
2420 scmd->sc_data_direction = DMA_BIDIRECTIONAL;
2421
2422 spin_lock_irqsave(shost->host_lock, flags);
2423 shost->tmf_in_progress = 1;
2424 spin_unlock_irqrestore(shost->host_lock, flags);
2425
2426 switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2427 case SG_SCSI_RESET_NOTHING:
2428 rtn = SUCCESS;
2429 break;
2430 case SG_SCSI_RESET_DEVICE:
2431 rtn = scsi_try_bus_device_reset(scmd);
2432 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2433 break;
2434 fallthrough;
2435 case SG_SCSI_RESET_TARGET:
2436 rtn = scsi_try_target_reset(scmd);
2437 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2438 break;
2439 fallthrough;
2440 case SG_SCSI_RESET_BUS:
2441 rtn = scsi_try_bus_reset(scmd);
2442 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2443 break;
2444 fallthrough;
2445 case SG_SCSI_RESET_HOST:
2446 rtn = scsi_try_host_reset(scmd);
2447 if (rtn == SUCCESS)
2448 break;
2449 fallthrough;
2450 default:
2451 rtn = FAILED;
2452 break;
2453 }
2454
2455 error = (rtn == SUCCESS) ? 0 : -EIO;
2456
2457 spin_lock_irqsave(shost->host_lock, flags);
2458 shost->tmf_in_progress = 0;
2459 spin_unlock_irqrestore(shost->host_lock, flags);
2460
2461 /*
2462 * be sure to wake up anyone who was sleeping or had their queue
2463 * suspended while we performed the TMF.
2464 */
2465 SCSI_LOG_ERROR_RECOVERY(3,
2466 shost_printk(KERN_INFO, shost,
2467 "waking up host to restart after TMF\n"));
2468
2469 wake_up(&shost->host_wait);
2470 scsi_run_host_queues(shost);
2471
2472 kfree(rq);
2473
2474out_put_autopm_host:
2475 scsi_autopm_put_host(shost);
2476 return error;
2477}
2478
2479bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2480 struct scsi_sense_hdr *sshdr)
2481{
2482 return scsi_normalize_sense(cmd->sense_buffer,
2483 SCSI_SENSE_BUFFERSIZE, sshdr);
2484}
2485EXPORT_SYMBOL(scsi_command_normalize_sense);
2486
2487/**
2488 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2489 * @sense_buffer: byte array of sense data
2490 * @sb_len: number of valid bytes in sense_buffer
2491 * @info_out: pointer to 64 integer where 8 or 4 byte information
2492 * field will be placed if found.
2493 *
2494 * Return value:
2495 * true if information field found, false if not found.
2496 */
2497bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2498 u64 *info_out)
2499{
2500 const u8 * ucp;
2501
2502 if (sb_len < 7)
2503 return false;
2504 switch (sense_buffer[0] & 0x7f) {
2505 case 0x70:
2506 case 0x71:
2507 if (sense_buffer[0] & 0x80) {
2508 *info_out = get_unaligned_be32(&sense_buffer[3]);
2509 return true;
2510 }
2511 return false;
2512 case 0x72:
2513 case 0x73:
2514 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2515 0 /* info desc */);
2516 if (ucp && (0xa == ucp[1])) {
2517 *info_out = get_unaligned_be64(&ucp[4]);
2518 return true;
2519 }
2520 return false;
2521 default:
2522 return false;
2523 }
2524}
2525EXPORT_SYMBOL(scsi_get_sense_info_fld);