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