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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12#include <linux/bio.h>
13#include <linux/bitops.h>
14#include <linux/blkdev.h>
15#include <linux/completion.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
21#include <linux/hardirq.h>
22#include <linux/scatterlist.h>
23#include <linux/blk-mq.h>
24#include <linux/ratelimit.h>
25#include <asm/unaligned.h>
26
27#include <scsi/scsi.h>
28#include <scsi/scsi_cmnd.h>
29#include <scsi/scsi_dbg.h>
30#include <scsi/scsi_device.h>
31#include <scsi/scsi_driver.h>
32#include <scsi/scsi_eh.h>
33#include <scsi/scsi_host.h>
34#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
35#include <scsi/scsi_dh.h>
36
37#include <trace/events/scsi.h>
38
39#include "scsi_debugfs.h"
40#include "scsi_priv.h"
41#include "scsi_logging.h"
42
43/*
44 * Size of integrity metadata is usually small, 1 inline sg should
45 * cover normal cases.
46 */
47#ifdef CONFIG_ARCH_NO_SG_CHAIN
48#define SCSI_INLINE_PROT_SG_CNT 0
49#define SCSI_INLINE_SG_CNT 0
50#else
51#define SCSI_INLINE_PROT_SG_CNT 1
52#define SCSI_INLINE_SG_CNT 2
53#endif
54
55static struct kmem_cache *scsi_sense_cache;
56static DEFINE_MUTEX(scsi_sense_cache_mutex);
57
58static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
59
60int scsi_init_sense_cache(struct Scsi_Host *shost)
61{
62 int ret = 0;
63
64 mutex_lock(&scsi_sense_cache_mutex);
65 if (!scsi_sense_cache) {
66 scsi_sense_cache =
67 kmem_cache_create_usercopy("scsi_sense_cache",
68 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
69 0, SCSI_SENSE_BUFFERSIZE, NULL);
70 if (!scsi_sense_cache)
71 ret = -ENOMEM;
72 }
73 mutex_unlock(&scsi_sense_cache_mutex);
74 return ret;
75}
76
77/*
78 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
79 * not change behaviour from the previous unplug mechanism, experimentation
80 * may prove this needs changing.
81 */
82#define SCSI_QUEUE_DELAY 3
83
84static void
85scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
86{
87 struct Scsi_Host *host = cmd->device->host;
88 struct scsi_device *device = cmd->device;
89 struct scsi_target *starget = scsi_target(device);
90
91 /*
92 * Set the appropriate busy bit for the device/host.
93 *
94 * If the host/device isn't busy, assume that something actually
95 * completed, and that we should be able to queue a command now.
96 *
97 * Note that the prior mid-layer assumption that any host could
98 * always queue at least one command is now broken. The mid-layer
99 * will implement a user specifiable stall (see
100 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
101 * if a command is requeued with no other commands outstanding
102 * either for the device or for the host.
103 */
104 switch (reason) {
105 case SCSI_MLQUEUE_HOST_BUSY:
106 atomic_set(&host->host_blocked, host->max_host_blocked);
107 break;
108 case SCSI_MLQUEUE_DEVICE_BUSY:
109 case SCSI_MLQUEUE_EH_RETRY:
110 atomic_set(&device->device_blocked,
111 device->max_device_blocked);
112 break;
113 case SCSI_MLQUEUE_TARGET_BUSY:
114 atomic_set(&starget->target_blocked,
115 starget->max_target_blocked);
116 break;
117 }
118}
119
120static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
121{
122 if (cmd->request->rq_flags & RQF_DONTPREP) {
123 cmd->request->rq_flags &= ~RQF_DONTPREP;
124 scsi_mq_uninit_cmd(cmd);
125 } else {
126 WARN_ON_ONCE(true);
127 }
128 blk_mq_requeue_request(cmd->request, true);
129}
130
131/**
132 * __scsi_queue_insert - private queue insertion
133 * @cmd: The SCSI command being requeued
134 * @reason: The reason for the requeue
135 * @unbusy: Whether the queue should be unbusied
136 *
137 * This is a private queue insertion. The public interface
138 * scsi_queue_insert() always assumes the queue should be unbusied
139 * because it's always called before the completion. This function is
140 * for a requeue after completion, which should only occur in this
141 * file.
142 */
143static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
144{
145 struct scsi_device *device = cmd->device;
146
147 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
148 "Inserting command %p into mlqueue\n", cmd));
149
150 scsi_set_blocked(cmd, reason);
151
152 /*
153 * Decrement the counters, since these commands are no longer
154 * active on the host/device.
155 */
156 if (unbusy)
157 scsi_device_unbusy(device, cmd);
158
159 /*
160 * Requeue this command. It will go before all other commands
161 * that are already in the queue. Schedule requeue work under
162 * lock such that the kblockd_schedule_work() call happens
163 * before blk_cleanup_queue() finishes.
164 */
165 cmd->result = 0;
166
167 blk_mq_requeue_request(cmd->request, true);
168}
169
170/**
171 * scsi_queue_insert - Reinsert a command in the queue.
172 * @cmd: command that we are adding to queue.
173 * @reason: why we are inserting command to queue.
174 *
175 * We do this for one of two cases. Either the host is busy and it cannot accept
176 * any more commands for the time being, or the device returned QUEUE_FULL and
177 * can accept no more commands.
178 *
179 * Context: This could be called either from an interrupt context or a normal
180 * process context.
181 */
182void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
183{
184 __scsi_queue_insert(cmd, reason, true);
185}
186
187
188/**
189 * __scsi_execute - insert request and wait for the result
190 * @sdev: scsi device
191 * @cmd: scsi command
192 * @data_direction: data direction
193 * @buffer: data buffer
194 * @bufflen: len of buffer
195 * @sense: optional sense buffer
196 * @sshdr: optional decoded sense header
197 * @timeout: request timeout in HZ
198 * @retries: number of times to retry request
199 * @flags: flags for ->cmd_flags
200 * @rq_flags: flags for ->rq_flags
201 * @resid: optional residual length
202 *
203 * Returns the scsi_cmnd result field if a command was executed, or a negative
204 * Linux error code if we didn't get that far.
205 */
206int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
207 int data_direction, void *buffer, unsigned bufflen,
208 unsigned char *sense, struct scsi_sense_hdr *sshdr,
209 int timeout, int retries, u64 flags, req_flags_t rq_flags,
210 int *resid)
211{
212 struct request *req;
213 struct scsi_request *rq;
214 int ret;
215
216 req = blk_get_request(sdev->request_queue,
217 data_direction == DMA_TO_DEVICE ?
218 REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
219 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
220 if (IS_ERR(req))
221 return PTR_ERR(req);
222
223 rq = scsi_req(req);
224
225 if (bufflen) {
226 ret = blk_rq_map_kern(sdev->request_queue, req,
227 buffer, bufflen, GFP_NOIO);
228 if (ret)
229 goto out;
230 }
231 rq->cmd_len = COMMAND_SIZE(cmd[0]);
232 memcpy(rq->cmd, cmd, rq->cmd_len);
233 rq->retries = retries;
234 req->timeout = timeout;
235 req->cmd_flags |= flags;
236 req->rq_flags |= rq_flags | RQF_QUIET;
237
238 /*
239 * head injection *required* here otherwise quiesce won't work
240 */
241 blk_execute_rq(NULL, req, 1);
242
243 /*
244 * Some devices (USB mass-storage in particular) may transfer
245 * garbage data together with a residue indicating that the data
246 * is invalid. Prevent the garbage from being misinterpreted
247 * and prevent security leaks by zeroing out the excess data.
248 */
249 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
250 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
251
252 if (resid)
253 *resid = rq->resid_len;
254 if (sense && rq->sense_len)
255 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
256 if (sshdr)
257 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
258 ret = rq->result;
259 out:
260 blk_put_request(req);
261
262 return ret;
263}
264EXPORT_SYMBOL(__scsi_execute);
265
266/*
267 * Wake up the error handler if necessary. Avoid as follows that the error
268 * handler is not woken up if host in-flight requests number ==
269 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
270 * with an RCU read lock in this function to ensure that this function in
271 * its entirety either finishes before scsi_eh_scmd_add() increases the
272 * host_failed counter or that it notices the shost state change made by
273 * scsi_eh_scmd_add().
274 */
275static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
276{
277 unsigned long flags;
278
279 rcu_read_lock();
280 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
281 if (unlikely(scsi_host_in_recovery(shost))) {
282 spin_lock_irqsave(shost->host_lock, flags);
283 if (shost->host_failed || shost->host_eh_scheduled)
284 scsi_eh_wakeup(shost);
285 spin_unlock_irqrestore(shost->host_lock, flags);
286 }
287 rcu_read_unlock();
288}
289
290void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
291{
292 struct Scsi_Host *shost = sdev->host;
293 struct scsi_target *starget = scsi_target(sdev);
294
295 scsi_dec_host_busy(shost, cmd);
296
297 if (starget->can_queue > 0)
298 atomic_dec(&starget->target_busy);
299
300 sbitmap_put(&sdev->budget_map, cmd->budget_token);
301 cmd->budget_token = -1;
302}
303
304static void scsi_kick_queue(struct request_queue *q)
305{
306 blk_mq_run_hw_queues(q, false);
307}
308
309/*
310 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
311 * and call blk_run_queue for all the scsi_devices on the target -
312 * including current_sdev first.
313 *
314 * Called with *no* scsi locks held.
315 */
316static void scsi_single_lun_run(struct scsi_device *current_sdev)
317{
318 struct Scsi_Host *shost = current_sdev->host;
319 struct scsi_device *sdev, *tmp;
320 struct scsi_target *starget = scsi_target(current_sdev);
321 unsigned long flags;
322
323 spin_lock_irqsave(shost->host_lock, flags);
324 starget->starget_sdev_user = NULL;
325 spin_unlock_irqrestore(shost->host_lock, flags);
326
327 /*
328 * Call blk_run_queue for all LUNs on the target, starting with
329 * current_sdev. We race with others (to set starget_sdev_user),
330 * but in most cases, we will be first. Ideally, each LU on the
331 * target would get some limited time or requests on the target.
332 */
333 scsi_kick_queue(current_sdev->request_queue);
334
335 spin_lock_irqsave(shost->host_lock, flags);
336 if (starget->starget_sdev_user)
337 goto out;
338 list_for_each_entry_safe(sdev, tmp, &starget->devices,
339 same_target_siblings) {
340 if (sdev == current_sdev)
341 continue;
342 if (scsi_device_get(sdev))
343 continue;
344
345 spin_unlock_irqrestore(shost->host_lock, flags);
346 scsi_kick_queue(sdev->request_queue);
347 spin_lock_irqsave(shost->host_lock, flags);
348
349 scsi_device_put(sdev);
350 }
351 out:
352 spin_unlock_irqrestore(shost->host_lock, flags);
353}
354
355static inline bool scsi_device_is_busy(struct scsi_device *sdev)
356{
357 if (scsi_device_busy(sdev) >= sdev->queue_depth)
358 return true;
359 if (atomic_read(&sdev->device_blocked) > 0)
360 return true;
361 return false;
362}
363
364static inline bool scsi_target_is_busy(struct scsi_target *starget)
365{
366 if (starget->can_queue > 0) {
367 if (atomic_read(&starget->target_busy) >= starget->can_queue)
368 return true;
369 if (atomic_read(&starget->target_blocked) > 0)
370 return true;
371 }
372 return false;
373}
374
375static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
376{
377 if (atomic_read(&shost->host_blocked) > 0)
378 return true;
379 if (shost->host_self_blocked)
380 return true;
381 return false;
382}
383
384static void scsi_starved_list_run(struct Scsi_Host *shost)
385{
386 LIST_HEAD(starved_list);
387 struct scsi_device *sdev;
388 unsigned long flags;
389
390 spin_lock_irqsave(shost->host_lock, flags);
391 list_splice_init(&shost->starved_list, &starved_list);
392
393 while (!list_empty(&starved_list)) {
394 struct request_queue *slq;
395
396 /*
397 * As long as shost is accepting commands and we have
398 * starved queues, call blk_run_queue. scsi_request_fn
399 * drops the queue_lock and can add us back to the
400 * starved_list.
401 *
402 * host_lock protects the starved_list and starved_entry.
403 * scsi_request_fn must get the host_lock before checking
404 * or modifying starved_list or starved_entry.
405 */
406 if (scsi_host_is_busy(shost))
407 break;
408
409 sdev = list_entry(starved_list.next,
410 struct scsi_device, starved_entry);
411 list_del_init(&sdev->starved_entry);
412 if (scsi_target_is_busy(scsi_target(sdev))) {
413 list_move_tail(&sdev->starved_entry,
414 &shost->starved_list);
415 continue;
416 }
417
418 /*
419 * Once we drop the host lock, a racing scsi_remove_device()
420 * call may remove the sdev from the starved list and destroy
421 * it and the queue. Mitigate by taking a reference to the
422 * queue and never touching the sdev again after we drop the
423 * host lock. Note: if __scsi_remove_device() invokes
424 * blk_cleanup_queue() before the queue is run from this
425 * function then blk_run_queue() will return immediately since
426 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
427 */
428 slq = sdev->request_queue;
429 if (!blk_get_queue(slq))
430 continue;
431 spin_unlock_irqrestore(shost->host_lock, flags);
432
433 scsi_kick_queue(slq);
434 blk_put_queue(slq);
435
436 spin_lock_irqsave(shost->host_lock, flags);
437 }
438 /* put any unprocessed entries back */
439 list_splice(&starved_list, &shost->starved_list);
440 spin_unlock_irqrestore(shost->host_lock, flags);
441}
442
443/**
444 * scsi_run_queue - Select a proper request queue to serve next.
445 * @q: last request's queue
446 *
447 * The previous command was completely finished, start a new one if possible.
448 */
449static void scsi_run_queue(struct request_queue *q)
450{
451 struct scsi_device *sdev = q->queuedata;
452
453 if (scsi_target(sdev)->single_lun)
454 scsi_single_lun_run(sdev);
455 if (!list_empty(&sdev->host->starved_list))
456 scsi_starved_list_run(sdev->host);
457
458 blk_mq_run_hw_queues(q, false);
459}
460
461void scsi_requeue_run_queue(struct work_struct *work)
462{
463 struct scsi_device *sdev;
464 struct request_queue *q;
465
466 sdev = container_of(work, struct scsi_device, requeue_work);
467 q = sdev->request_queue;
468 scsi_run_queue(q);
469}
470
471void scsi_run_host_queues(struct Scsi_Host *shost)
472{
473 struct scsi_device *sdev;
474
475 shost_for_each_device(sdev, shost)
476 scsi_run_queue(sdev->request_queue);
477}
478
479static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
480{
481 if (!blk_rq_is_passthrough(cmd->request)) {
482 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
483
484 if (drv->uninit_command)
485 drv->uninit_command(cmd);
486 }
487}
488
489void scsi_free_sgtables(struct scsi_cmnd *cmd)
490{
491 if (cmd->sdb.table.nents)
492 sg_free_table_chained(&cmd->sdb.table,
493 SCSI_INLINE_SG_CNT);
494 if (scsi_prot_sg_count(cmd))
495 sg_free_table_chained(&cmd->prot_sdb->table,
496 SCSI_INLINE_PROT_SG_CNT);
497}
498EXPORT_SYMBOL_GPL(scsi_free_sgtables);
499
500static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
501{
502 scsi_free_sgtables(cmd);
503 scsi_uninit_cmd(cmd);
504}
505
506static void scsi_run_queue_async(struct scsi_device *sdev)
507{
508 if (scsi_target(sdev)->single_lun ||
509 !list_empty(&sdev->host->starved_list)) {
510 kblockd_schedule_work(&sdev->requeue_work);
511 } else {
512 /*
513 * smp_mb() present in sbitmap_queue_clear() or implied in
514 * .end_io is for ordering writing .device_busy in
515 * scsi_device_unbusy() and reading sdev->restarts.
516 */
517 int old = atomic_read(&sdev->restarts);
518
519 /*
520 * ->restarts has to be kept as non-zero if new budget
521 * contention occurs.
522 *
523 * No need to run queue when either another re-run
524 * queue wins in updating ->restarts or a new budget
525 * contention occurs.
526 */
527 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
528 blk_mq_run_hw_queues(sdev->request_queue, true);
529 }
530}
531
532/* Returns false when no more bytes to process, true if there are more */
533static bool scsi_end_request(struct request *req, blk_status_t error,
534 unsigned int bytes)
535{
536 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
537 struct scsi_device *sdev = cmd->device;
538 struct request_queue *q = sdev->request_queue;
539
540 if (blk_update_request(req, error, bytes))
541 return true;
542
543 if (blk_queue_add_random(q))
544 add_disk_randomness(req->rq_disk);
545
546 if (!blk_rq_is_passthrough(req)) {
547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
548 cmd->flags &= ~SCMD_INITIALIZED;
549 }
550
551 /*
552 * Calling rcu_barrier() is not necessary here because the
553 * SCSI error handler guarantees that the function called by
554 * call_rcu() has been called before scsi_end_request() is
555 * called.
556 */
557 destroy_rcu_head(&cmd->rcu);
558
559 /*
560 * In the MQ case the command gets freed by __blk_mq_end_request,
561 * so we have to do all cleanup that depends on it earlier.
562 *
563 * We also can't kick the queues from irq context, so we
564 * will have to defer it to a workqueue.
565 */
566 scsi_mq_uninit_cmd(cmd);
567
568 /*
569 * queue is still alive, so grab the ref for preventing it
570 * from being cleaned up during running queue.
571 */
572 percpu_ref_get(&q->q_usage_counter);
573
574 __blk_mq_end_request(req, error);
575
576 scsi_run_queue_async(sdev);
577
578 percpu_ref_put(&q->q_usage_counter);
579 return false;
580}
581
582/**
583 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
584 * @cmd: SCSI command
585 * @result: scsi error code
586 *
587 * Translate a SCSI result code into a blk_status_t value. May reset the host
588 * byte of @cmd->result.
589 */
590static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
591{
592 switch (host_byte(result)) {
593 case DID_OK:
594 if (scsi_status_is_good(result))
595 return BLK_STS_OK;
596 return BLK_STS_IOERR;
597 case DID_TRANSPORT_FAILFAST:
598 case DID_TRANSPORT_MARGINAL:
599 return BLK_STS_TRANSPORT;
600 case DID_TARGET_FAILURE:
601 set_host_byte(cmd, DID_OK);
602 return BLK_STS_TARGET;
603 case DID_NEXUS_FAILURE:
604 set_host_byte(cmd, DID_OK);
605 return BLK_STS_NEXUS;
606 case DID_ALLOC_FAILURE:
607 set_host_byte(cmd, DID_OK);
608 return BLK_STS_NOSPC;
609 case DID_MEDIUM_ERROR:
610 set_host_byte(cmd, DID_OK);
611 return BLK_STS_MEDIUM;
612 default:
613 return BLK_STS_IOERR;
614 }
615}
616
617/* Helper for scsi_io_completion() when "reprep" action required. */
618static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
619 struct request_queue *q)
620{
621 /* A new command will be prepared and issued. */
622 scsi_mq_requeue_cmd(cmd);
623}
624
625static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
626{
627 struct request *req = cmd->request;
628 unsigned long wait_for;
629
630 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
631 return false;
632
633 wait_for = (cmd->allowed + 1) * req->timeout;
634 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
635 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
636 wait_for/HZ);
637 return true;
638 }
639 return false;
640}
641
642/* Helper for scsi_io_completion() when special action required. */
643static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
644{
645 struct request_queue *q = cmd->device->request_queue;
646 struct request *req = cmd->request;
647 int level = 0;
648 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
649 ACTION_DELAYED_RETRY} action;
650 struct scsi_sense_hdr sshdr;
651 bool sense_valid;
652 bool sense_current = true; /* false implies "deferred sense" */
653 blk_status_t blk_stat;
654
655 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
656 if (sense_valid)
657 sense_current = !scsi_sense_is_deferred(&sshdr);
658
659 blk_stat = scsi_result_to_blk_status(cmd, result);
660
661 if (host_byte(result) == DID_RESET) {
662 /* Third party bus reset or reset for error recovery
663 * reasons. Just retry the command and see what
664 * happens.
665 */
666 action = ACTION_RETRY;
667 } else if (sense_valid && sense_current) {
668 switch (sshdr.sense_key) {
669 case UNIT_ATTENTION:
670 if (cmd->device->removable) {
671 /* Detected disc change. Set a bit
672 * and quietly refuse further access.
673 */
674 cmd->device->changed = 1;
675 action = ACTION_FAIL;
676 } else {
677 /* Must have been a power glitch, or a
678 * bus reset. Could not have been a
679 * media change, so we just retry the
680 * command and see what happens.
681 */
682 action = ACTION_RETRY;
683 }
684 break;
685 case ILLEGAL_REQUEST:
686 /* If we had an ILLEGAL REQUEST returned, then
687 * we may have performed an unsupported
688 * command. The only thing this should be
689 * would be a ten byte read where only a six
690 * byte read was supported. Also, on a system
691 * where READ CAPACITY failed, we may have
692 * read past the end of the disk.
693 */
694 if ((cmd->device->use_10_for_rw &&
695 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
696 (cmd->cmnd[0] == READ_10 ||
697 cmd->cmnd[0] == WRITE_10)) {
698 /* This will issue a new 6-byte command. */
699 cmd->device->use_10_for_rw = 0;
700 action = ACTION_REPREP;
701 } else if (sshdr.asc == 0x10) /* DIX */ {
702 action = ACTION_FAIL;
703 blk_stat = BLK_STS_PROTECTION;
704 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
705 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
706 action = ACTION_FAIL;
707 blk_stat = BLK_STS_TARGET;
708 } else
709 action = ACTION_FAIL;
710 break;
711 case ABORTED_COMMAND:
712 action = ACTION_FAIL;
713 if (sshdr.asc == 0x10) /* DIF */
714 blk_stat = BLK_STS_PROTECTION;
715 break;
716 case NOT_READY:
717 /* If the device is in the process of becoming
718 * ready, or has a temporary blockage, retry.
719 */
720 if (sshdr.asc == 0x04) {
721 switch (sshdr.ascq) {
722 case 0x01: /* becoming ready */
723 case 0x04: /* format in progress */
724 case 0x05: /* rebuild in progress */
725 case 0x06: /* recalculation in progress */
726 case 0x07: /* operation in progress */
727 case 0x08: /* Long write in progress */
728 case 0x09: /* self test in progress */
729 case 0x11: /* notify (enable spinup) required */
730 case 0x14: /* space allocation in progress */
731 case 0x1a: /* start stop unit in progress */
732 case 0x1b: /* sanitize in progress */
733 case 0x1d: /* configuration in progress */
734 case 0x24: /* depopulation in progress */
735 action = ACTION_DELAYED_RETRY;
736 break;
737 case 0x0a: /* ALUA state transition */
738 blk_stat = BLK_STS_AGAIN;
739 fallthrough;
740 default:
741 action = ACTION_FAIL;
742 break;
743 }
744 } else
745 action = ACTION_FAIL;
746 break;
747 case VOLUME_OVERFLOW:
748 /* See SSC3rXX or current. */
749 action = ACTION_FAIL;
750 break;
751 case DATA_PROTECT:
752 action = ACTION_FAIL;
753 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
754 (sshdr.asc == 0x55 &&
755 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
756 /* Insufficient zone resources */
757 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
758 }
759 break;
760 default:
761 action = ACTION_FAIL;
762 break;
763 }
764 } else
765 action = ACTION_FAIL;
766
767 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
768 action = ACTION_FAIL;
769
770 switch (action) {
771 case ACTION_FAIL:
772 /* Give up and fail the remainder of the request */
773 if (!(req->rq_flags & RQF_QUIET)) {
774 static DEFINE_RATELIMIT_STATE(_rs,
775 DEFAULT_RATELIMIT_INTERVAL,
776 DEFAULT_RATELIMIT_BURST);
777
778 if (unlikely(scsi_logging_level))
779 level =
780 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
781 SCSI_LOG_MLCOMPLETE_BITS);
782
783 /*
784 * if logging is enabled the failure will be printed
785 * in scsi_log_completion(), so avoid duplicate messages
786 */
787 if (!level && __ratelimit(&_rs)) {
788 scsi_print_result(cmd, NULL, FAILED);
789 if (sense_valid)
790 scsi_print_sense(cmd);
791 scsi_print_command(cmd);
792 }
793 }
794 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
795 return;
796 fallthrough;
797 case ACTION_REPREP:
798 scsi_io_completion_reprep(cmd, q);
799 break;
800 case ACTION_RETRY:
801 /* Retry the same command immediately */
802 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
803 break;
804 case ACTION_DELAYED_RETRY:
805 /* Retry the same command after a delay */
806 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
807 break;
808 }
809}
810
811/*
812 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
813 * new result that may suppress further error checking. Also modifies
814 * *blk_statp in some cases.
815 */
816static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
817 blk_status_t *blk_statp)
818{
819 bool sense_valid;
820 bool sense_current = true; /* false implies "deferred sense" */
821 struct request *req = cmd->request;
822 struct scsi_sense_hdr sshdr;
823
824 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
825 if (sense_valid)
826 sense_current = !scsi_sense_is_deferred(&sshdr);
827
828 if (blk_rq_is_passthrough(req)) {
829 if (sense_valid) {
830 /*
831 * SG_IO wants current and deferred errors
832 */
833 scsi_req(req)->sense_len =
834 min(8 + cmd->sense_buffer[7],
835 SCSI_SENSE_BUFFERSIZE);
836 }
837 if (sense_current)
838 *blk_statp = scsi_result_to_blk_status(cmd, result);
839 } else if (blk_rq_bytes(req) == 0 && sense_current) {
840 /*
841 * Flush commands do not transfers any data, and thus cannot use
842 * good_bytes != blk_rq_bytes(req) as the signal for an error.
843 * This sets *blk_statp explicitly for the problem case.
844 */
845 *blk_statp = scsi_result_to_blk_status(cmd, result);
846 }
847 /*
848 * Recovered errors need reporting, but they're always treated as
849 * success, so fiddle the result code here. For passthrough requests
850 * we already took a copy of the original into sreq->result which
851 * is what gets returned to the user
852 */
853 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
854 bool do_print = true;
855 /*
856 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
857 * skip print since caller wants ATA registers. Only occurs
858 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
859 */
860 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
861 do_print = false;
862 else if (req->rq_flags & RQF_QUIET)
863 do_print = false;
864 if (do_print)
865 scsi_print_sense(cmd);
866 result = 0;
867 /* for passthrough, *blk_statp may be set */
868 *blk_statp = BLK_STS_OK;
869 }
870 /*
871 * Another corner case: the SCSI status byte is non-zero but 'good'.
872 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
873 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
874 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
875 * intermediate statuses (both obsolete in SAM-4) as good.
876 */
877 if ((result & 0xff) && scsi_status_is_good(result)) {
878 result = 0;
879 *blk_statp = BLK_STS_OK;
880 }
881 return result;
882}
883
884/**
885 * scsi_io_completion - Completion processing for SCSI commands.
886 * @cmd: command that is finished.
887 * @good_bytes: number of processed bytes.
888 *
889 * We will finish off the specified number of sectors. If we are done, the
890 * command block will be released and the queue function will be goosed. If we
891 * are not done then we have to figure out what to do next:
892 *
893 * a) We can call scsi_io_completion_reprep(). The request will be
894 * unprepared and put back on the queue. Then a new command will
895 * be created for it. This should be used if we made forward
896 * progress, or if we want to switch from READ(10) to READ(6) for
897 * example.
898 *
899 * b) We can call scsi_io_completion_action(). The request will be
900 * put back on the queue and retried using the same command as
901 * before, possibly after a delay.
902 *
903 * c) We can call scsi_end_request() with blk_stat other than
904 * BLK_STS_OK, to fail the remainder of the request.
905 */
906void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
907{
908 int result = cmd->result;
909 struct request_queue *q = cmd->device->request_queue;
910 struct request *req = cmd->request;
911 blk_status_t blk_stat = BLK_STS_OK;
912
913 if (unlikely(result)) /* a nz result may or may not be an error */
914 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
915
916 if (unlikely(blk_rq_is_passthrough(req))) {
917 /*
918 * scsi_result_to_blk_status may have reset the host_byte
919 */
920 scsi_req(req)->result = cmd->result;
921 }
922
923 /*
924 * Next deal with any sectors which we were able to correctly
925 * handle.
926 */
927 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
928 "%u sectors total, %d bytes done.\n",
929 blk_rq_sectors(req), good_bytes));
930
931 /*
932 * Failed, zero length commands always need to drop down
933 * to retry code. Fast path should return in this block.
934 */
935 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
936 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
937 return; /* no bytes remaining */
938 }
939
940 /* Kill remainder if no retries. */
941 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
942 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
943 WARN_ONCE(true,
944 "Bytes remaining after failed, no-retry command");
945 return;
946 }
947
948 /*
949 * If there had been no error, but we have leftover bytes in the
950 * requeues just queue the command up again.
951 */
952 if (likely(result == 0))
953 scsi_io_completion_reprep(cmd, q);
954 else
955 scsi_io_completion_action(cmd, result);
956}
957
958static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
959 struct request *rq)
960{
961 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
962 !op_is_write(req_op(rq)) &&
963 sdev->host->hostt->dma_need_drain(rq);
964}
965
966/**
967 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
968 * @cmd: SCSI command data structure to initialize.
969 *
970 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
971 * for @cmd.
972 *
973 * Returns:
974 * * BLK_STS_OK - on success
975 * * BLK_STS_RESOURCE - if the failure is retryable
976 * * BLK_STS_IOERR - if the failure is fatal
977 */
978blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
979{
980 struct scsi_device *sdev = cmd->device;
981 struct request *rq = cmd->request;
982 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
983 struct scatterlist *last_sg = NULL;
984 blk_status_t ret;
985 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
986 int count;
987
988 if (WARN_ON_ONCE(!nr_segs))
989 return BLK_STS_IOERR;
990
991 /*
992 * Make sure there is space for the drain. The driver must adjust
993 * max_hw_segments to be prepared for this.
994 */
995 if (need_drain)
996 nr_segs++;
997
998 /*
999 * If sg table allocation fails, requeue request later.
1000 */
1001 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1002 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1003 return BLK_STS_RESOURCE;
1004
1005 /*
1006 * Next, walk the list, and fill in the addresses and sizes of
1007 * each segment.
1008 */
1009 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1010
1011 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1012 unsigned int pad_len =
1013 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1014
1015 last_sg->length += pad_len;
1016 cmd->extra_len += pad_len;
1017 }
1018
1019 if (need_drain) {
1020 sg_unmark_end(last_sg);
1021 last_sg = sg_next(last_sg);
1022 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1023 sg_mark_end(last_sg);
1024
1025 cmd->extra_len += sdev->dma_drain_len;
1026 count++;
1027 }
1028
1029 BUG_ON(count > cmd->sdb.table.nents);
1030 cmd->sdb.table.nents = count;
1031 cmd->sdb.length = blk_rq_payload_bytes(rq);
1032
1033 if (blk_integrity_rq(rq)) {
1034 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1035 int ivecs;
1036
1037 if (WARN_ON_ONCE(!prot_sdb)) {
1038 /*
1039 * This can happen if someone (e.g. multipath)
1040 * queues a command to a device on an adapter
1041 * that does not support DIX.
1042 */
1043 ret = BLK_STS_IOERR;
1044 goto out_free_sgtables;
1045 }
1046
1047 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1048
1049 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1050 prot_sdb->table.sgl,
1051 SCSI_INLINE_PROT_SG_CNT)) {
1052 ret = BLK_STS_RESOURCE;
1053 goto out_free_sgtables;
1054 }
1055
1056 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1057 prot_sdb->table.sgl);
1058 BUG_ON(count > ivecs);
1059 BUG_ON(count > queue_max_integrity_segments(rq->q));
1060
1061 cmd->prot_sdb = prot_sdb;
1062 cmd->prot_sdb->table.nents = count;
1063 }
1064
1065 return BLK_STS_OK;
1066out_free_sgtables:
1067 scsi_free_sgtables(cmd);
1068 return ret;
1069}
1070EXPORT_SYMBOL(scsi_alloc_sgtables);
1071
1072/**
1073 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1074 * @rq: Request associated with the SCSI command to be initialized.
1075 *
1076 * This function initializes the members of struct scsi_cmnd that must be
1077 * initialized before request processing starts and that won't be
1078 * reinitialized if a SCSI command is requeued.
1079 *
1080 * Called from inside blk_get_request() for pass-through requests and from
1081 * inside scsi_init_command() for filesystem requests.
1082 */
1083static void scsi_initialize_rq(struct request *rq)
1084{
1085 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1086
1087 scsi_req_init(&cmd->req);
1088 init_rcu_head(&cmd->rcu);
1089 cmd->jiffies_at_alloc = jiffies;
1090 cmd->retries = 0;
1091}
1092
1093/*
1094 * Only called when the request isn't completed by SCSI, and not freed by
1095 * SCSI
1096 */
1097static void scsi_cleanup_rq(struct request *rq)
1098{
1099 if (rq->rq_flags & RQF_DONTPREP) {
1100 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1101 rq->rq_flags &= ~RQF_DONTPREP;
1102 }
1103}
1104
1105/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1106void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1107{
1108 void *buf = cmd->sense_buffer;
1109 void *prot = cmd->prot_sdb;
1110 struct request *rq = blk_mq_rq_from_pdu(cmd);
1111 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1112 unsigned long jiffies_at_alloc;
1113 int retries, to_clear;
1114 bool in_flight;
1115 int budget_token = cmd->budget_token;
1116
1117 if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) {
1118 flags |= SCMD_INITIALIZED;
1119 scsi_initialize_rq(rq);
1120 }
1121
1122 jiffies_at_alloc = cmd->jiffies_at_alloc;
1123 retries = cmd->retries;
1124 in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1125 /*
1126 * Zero out the cmd, except for the embedded scsi_request. Only clear
1127 * the driver-private command data if the LLD does not supply a
1128 * function to initialize that data.
1129 */
1130 to_clear = sizeof(*cmd) - sizeof(cmd->req);
1131 if (!dev->host->hostt->init_cmd_priv)
1132 to_clear += dev->host->hostt->cmd_size;
1133 memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
1134
1135 cmd->device = dev;
1136 cmd->sense_buffer = buf;
1137 cmd->prot_sdb = prot;
1138 cmd->flags = flags;
1139 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1140 cmd->jiffies_at_alloc = jiffies_at_alloc;
1141 cmd->retries = retries;
1142 if (in_flight)
1143 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1144 cmd->budget_token = budget_token;
1145
1146}
1147
1148static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1149 struct request *req)
1150{
1151 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1152
1153 /*
1154 * Passthrough requests may transfer data, in which case they must
1155 * a bio attached to them. Or they might contain a SCSI command
1156 * that does not transfer data, in which case they may optionally
1157 * submit a request without an attached bio.
1158 */
1159 if (req->bio) {
1160 blk_status_t ret = scsi_alloc_sgtables(cmd);
1161 if (unlikely(ret != BLK_STS_OK))
1162 return ret;
1163 } else {
1164 BUG_ON(blk_rq_bytes(req));
1165
1166 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1167 }
1168
1169 cmd->cmd_len = scsi_req(req)->cmd_len;
1170 if (cmd->cmd_len == 0)
1171 cmd->cmd_len = scsi_command_size(cmd->cmnd);
1172 cmd->cmnd = scsi_req(req)->cmd;
1173 cmd->transfersize = blk_rq_bytes(req);
1174 cmd->allowed = scsi_req(req)->retries;
1175 return BLK_STS_OK;
1176}
1177
1178static blk_status_t
1179scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1180{
1181 switch (sdev->sdev_state) {
1182 case SDEV_CREATED:
1183 return BLK_STS_OK;
1184 case SDEV_OFFLINE:
1185 case SDEV_TRANSPORT_OFFLINE:
1186 /*
1187 * If the device is offline we refuse to process any
1188 * commands. The device must be brought online
1189 * before trying any recovery commands.
1190 */
1191 if (!sdev->offline_already) {
1192 sdev->offline_already = true;
1193 sdev_printk(KERN_ERR, sdev,
1194 "rejecting I/O to offline device\n");
1195 }
1196 return BLK_STS_IOERR;
1197 case SDEV_DEL:
1198 /*
1199 * If the device is fully deleted, we refuse to
1200 * process any commands as well.
1201 */
1202 sdev_printk(KERN_ERR, sdev,
1203 "rejecting I/O to dead device\n");
1204 return BLK_STS_IOERR;
1205 case SDEV_BLOCK:
1206 case SDEV_CREATED_BLOCK:
1207 return BLK_STS_RESOURCE;
1208 case SDEV_QUIESCE:
1209 /*
1210 * If the device is blocked we only accept power management
1211 * commands.
1212 */
1213 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1214 return BLK_STS_RESOURCE;
1215 return BLK_STS_OK;
1216 default:
1217 /*
1218 * For any other not fully online state we only allow
1219 * power management commands.
1220 */
1221 if (req && !(req->rq_flags & RQF_PM))
1222 return BLK_STS_IOERR;
1223 return BLK_STS_OK;
1224 }
1225}
1226
1227/*
1228 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1229 * and return the token else return -1.
1230 */
1231static inline int scsi_dev_queue_ready(struct request_queue *q,
1232 struct scsi_device *sdev)
1233{
1234 int token;
1235
1236 token = sbitmap_get(&sdev->budget_map);
1237 if (atomic_read(&sdev->device_blocked)) {
1238 if (token < 0)
1239 goto out;
1240
1241 if (scsi_device_busy(sdev) > 1)
1242 goto out_dec;
1243
1244 /*
1245 * unblock after device_blocked iterates to zero
1246 */
1247 if (atomic_dec_return(&sdev->device_blocked) > 0)
1248 goto out_dec;
1249 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1250 "unblocking device at zero depth\n"));
1251 }
1252
1253 return token;
1254out_dec:
1255 if (token >= 0)
1256 sbitmap_put(&sdev->budget_map, token);
1257out:
1258 return -1;
1259}
1260
1261/*
1262 * scsi_target_queue_ready: checks if there we can send commands to target
1263 * @sdev: scsi device on starget to check.
1264 */
1265static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1266 struct scsi_device *sdev)
1267{
1268 struct scsi_target *starget = scsi_target(sdev);
1269 unsigned int busy;
1270
1271 if (starget->single_lun) {
1272 spin_lock_irq(shost->host_lock);
1273 if (starget->starget_sdev_user &&
1274 starget->starget_sdev_user != sdev) {
1275 spin_unlock_irq(shost->host_lock);
1276 return 0;
1277 }
1278 starget->starget_sdev_user = sdev;
1279 spin_unlock_irq(shost->host_lock);
1280 }
1281
1282 if (starget->can_queue <= 0)
1283 return 1;
1284
1285 busy = atomic_inc_return(&starget->target_busy) - 1;
1286 if (atomic_read(&starget->target_blocked) > 0) {
1287 if (busy)
1288 goto starved;
1289
1290 /*
1291 * unblock after target_blocked iterates to zero
1292 */
1293 if (atomic_dec_return(&starget->target_blocked) > 0)
1294 goto out_dec;
1295
1296 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1297 "unblocking target at zero depth\n"));
1298 }
1299
1300 if (busy >= starget->can_queue)
1301 goto starved;
1302
1303 return 1;
1304
1305starved:
1306 spin_lock_irq(shost->host_lock);
1307 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1308 spin_unlock_irq(shost->host_lock);
1309out_dec:
1310 if (starget->can_queue > 0)
1311 atomic_dec(&starget->target_busy);
1312 return 0;
1313}
1314
1315/*
1316 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1317 * return 0. We must end up running the queue again whenever 0 is
1318 * returned, else IO can hang.
1319 */
1320static inline int scsi_host_queue_ready(struct request_queue *q,
1321 struct Scsi_Host *shost,
1322 struct scsi_device *sdev,
1323 struct scsi_cmnd *cmd)
1324{
1325 if (scsi_host_in_recovery(shost))
1326 return 0;
1327
1328 if (atomic_read(&shost->host_blocked) > 0) {
1329 if (scsi_host_busy(shost) > 0)
1330 goto starved;
1331
1332 /*
1333 * unblock after host_blocked iterates to zero
1334 */
1335 if (atomic_dec_return(&shost->host_blocked) > 0)
1336 goto out_dec;
1337
1338 SCSI_LOG_MLQUEUE(3,
1339 shost_printk(KERN_INFO, shost,
1340 "unblocking host at zero depth\n"));
1341 }
1342
1343 if (shost->host_self_blocked)
1344 goto starved;
1345
1346 /* We're OK to process the command, so we can't be starved */
1347 if (!list_empty(&sdev->starved_entry)) {
1348 spin_lock_irq(shost->host_lock);
1349 if (!list_empty(&sdev->starved_entry))
1350 list_del_init(&sdev->starved_entry);
1351 spin_unlock_irq(shost->host_lock);
1352 }
1353
1354 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1355
1356 return 1;
1357
1358starved:
1359 spin_lock_irq(shost->host_lock);
1360 if (list_empty(&sdev->starved_entry))
1361 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1362 spin_unlock_irq(shost->host_lock);
1363out_dec:
1364 scsi_dec_host_busy(shost, cmd);
1365 return 0;
1366}
1367
1368/*
1369 * Busy state exporting function for request stacking drivers.
1370 *
1371 * For efficiency, no lock is taken to check the busy state of
1372 * shost/starget/sdev, since the returned value is not guaranteed and
1373 * may be changed after request stacking drivers call the function,
1374 * regardless of taking lock or not.
1375 *
1376 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1377 * needs to return 'not busy'. Otherwise, request stacking drivers
1378 * may hold requests forever.
1379 */
1380static bool scsi_mq_lld_busy(struct request_queue *q)
1381{
1382 struct scsi_device *sdev = q->queuedata;
1383 struct Scsi_Host *shost;
1384
1385 if (blk_queue_dying(q))
1386 return false;
1387
1388 shost = sdev->host;
1389
1390 /*
1391 * Ignore host/starget busy state.
1392 * Since block layer does not have a concept of fairness across
1393 * multiple queues, congestion of host/starget needs to be handled
1394 * in SCSI layer.
1395 */
1396 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1397 return true;
1398
1399 return false;
1400}
1401
1402/*
1403 * Block layer request completion callback. May be called from interrupt
1404 * context.
1405 */
1406static void scsi_complete(struct request *rq)
1407{
1408 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1409 enum scsi_disposition disposition;
1410
1411 INIT_LIST_HEAD(&cmd->eh_entry);
1412
1413 atomic_inc(&cmd->device->iodone_cnt);
1414 if (cmd->result)
1415 atomic_inc(&cmd->device->ioerr_cnt);
1416
1417 disposition = scsi_decide_disposition(cmd);
1418 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1419 disposition = SUCCESS;
1420
1421 scsi_log_completion(cmd, disposition);
1422
1423 switch (disposition) {
1424 case SUCCESS:
1425 scsi_finish_command(cmd);
1426 break;
1427 case NEEDS_RETRY:
1428 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1429 break;
1430 case ADD_TO_MLQUEUE:
1431 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1432 break;
1433 default:
1434 scsi_eh_scmd_add(cmd);
1435 break;
1436 }
1437}
1438
1439/**
1440 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1441 * @cmd: command block we are dispatching.
1442 *
1443 * Return: nonzero return request was rejected and device's queue needs to be
1444 * plugged.
1445 */
1446static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1447{
1448 struct Scsi_Host *host = cmd->device->host;
1449 int rtn = 0;
1450
1451 atomic_inc(&cmd->device->iorequest_cnt);
1452
1453 /* check if the device is still usable */
1454 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1455 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1456 * returns an immediate error upwards, and signals
1457 * that the device is no longer present */
1458 cmd->result = DID_NO_CONNECT << 16;
1459 goto done;
1460 }
1461
1462 /* Check to see if the scsi lld made this device blocked. */
1463 if (unlikely(scsi_device_blocked(cmd->device))) {
1464 /*
1465 * in blocked state, the command is just put back on
1466 * the device queue. The suspend state has already
1467 * blocked the queue so future requests should not
1468 * occur until the device transitions out of the
1469 * suspend state.
1470 */
1471 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1472 "queuecommand : device blocked\n"));
1473 return SCSI_MLQUEUE_DEVICE_BUSY;
1474 }
1475
1476 /* Store the LUN value in cmnd, if needed. */
1477 if (cmd->device->lun_in_cdb)
1478 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1479 (cmd->device->lun << 5 & 0xe0);
1480
1481 scsi_log_send(cmd);
1482
1483 /*
1484 * Before we queue this command, check if the command
1485 * length exceeds what the host adapter can handle.
1486 */
1487 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1488 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1489 "queuecommand : command too long. "
1490 "cdb_size=%d host->max_cmd_len=%d\n",
1491 cmd->cmd_len, cmd->device->host->max_cmd_len));
1492 cmd->result = (DID_ABORT << 16);
1493 goto done;
1494 }
1495
1496 if (unlikely(host->shost_state == SHOST_DEL)) {
1497 cmd->result = (DID_NO_CONNECT << 16);
1498 goto done;
1499
1500 }
1501
1502 trace_scsi_dispatch_cmd_start(cmd);
1503 rtn = host->hostt->queuecommand(host, cmd);
1504 if (rtn) {
1505 trace_scsi_dispatch_cmd_error(cmd, rtn);
1506 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1507 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1508 rtn = SCSI_MLQUEUE_HOST_BUSY;
1509
1510 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1511 "queuecommand : request rejected\n"));
1512 }
1513
1514 return rtn;
1515 done:
1516 cmd->scsi_done(cmd);
1517 return 0;
1518}
1519
1520/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1521static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1522{
1523 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1524 sizeof(struct scatterlist);
1525}
1526
1527static blk_status_t scsi_prepare_cmd(struct request *req)
1528{
1529 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1530 struct scsi_device *sdev = req->q->queuedata;
1531 struct Scsi_Host *shost = sdev->host;
1532 struct scatterlist *sg;
1533
1534 scsi_init_command(sdev, cmd);
1535
1536 cmd->request = req;
1537 cmd->tag = req->tag;
1538 cmd->prot_op = SCSI_PROT_NORMAL;
1539 if (blk_rq_bytes(req))
1540 cmd->sc_data_direction = rq_dma_dir(req);
1541 else
1542 cmd->sc_data_direction = DMA_NONE;
1543
1544 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1545 cmd->sdb.table.sgl = sg;
1546
1547 if (scsi_host_get_prot(shost)) {
1548 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1549
1550 cmd->prot_sdb->table.sgl =
1551 (struct scatterlist *)(cmd->prot_sdb + 1);
1552 }
1553
1554 /*
1555 * Special handling for passthrough commands, which don't go to the ULP
1556 * at all:
1557 */
1558 if (blk_rq_is_passthrough(req))
1559 return scsi_setup_scsi_cmnd(sdev, req);
1560
1561 if (sdev->handler && sdev->handler->prep_fn) {
1562 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1563
1564 if (ret != BLK_STS_OK)
1565 return ret;
1566 }
1567
1568 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1569 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1570 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1571}
1572
1573static void scsi_mq_done(struct scsi_cmnd *cmd)
1574{
1575 if (unlikely(blk_should_fake_timeout(cmd->request->q)))
1576 return;
1577 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1578 return;
1579 trace_scsi_dispatch_cmd_done(cmd);
1580 blk_mq_complete_request(cmd->request);
1581}
1582
1583static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1584{
1585 struct scsi_device *sdev = q->queuedata;
1586
1587 sbitmap_put(&sdev->budget_map, budget_token);
1588}
1589
1590static int scsi_mq_get_budget(struct request_queue *q)
1591{
1592 struct scsi_device *sdev = q->queuedata;
1593 int token = scsi_dev_queue_ready(q, sdev);
1594
1595 if (token >= 0)
1596 return token;
1597
1598 atomic_inc(&sdev->restarts);
1599
1600 /*
1601 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1602 * .restarts must be incremented before .device_busy is read because the
1603 * code in scsi_run_queue_async() depends on the order of these operations.
1604 */
1605 smp_mb__after_atomic();
1606
1607 /*
1608 * If all in-flight requests originated from this LUN are completed
1609 * before reading .device_busy, sdev->device_busy will be observed as
1610 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1611 * soon. Otherwise, completion of one of these requests will observe
1612 * the .restarts flag, and the request queue will be run for handling
1613 * this request, see scsi_end_request().
1614 */
1615 if (unlikely(scsi_device_busy(sdev) == 0 &&
1616 !scsi_device_blocked(sdev)))
1617 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1618 return -1;
1619}
1620
1621static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1622{
1623 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1624
1625 cmd->budget_token = token;
1626}
1627
1628static int scsi_mq_get_rq_budget_token(struct request *req)
1629{
1630 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1631
1632 return cmd->budget_token;
1633}
1634
1635static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1636 const struct blk_mq_queue_data *bd)
1637{
1638 struct request *req = bd->rq;
1639 struct request_queue *q = req->q;
1640 struct scsi_device *sdev = q->queuedata;
1641 struct Scsi_Host *shost = sdev->host;
1642 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1643 blk_status_t ret;
1644 int reason;
1645
1646 WARN_ON_ONCE(cmd->budget_token < 0);
1647
1648 /*
1649 * If the device is not in running state we will reject some or all
1650 * commands.
1651 */
1652 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1653 ret = scsi_device_state_check(sdev, req);
1654 if (ret != BLK_STS_OK)
1655 goto out_put_budget;
1656 }
1657
1658 ret = BLK_STS_RESOURCE;
1659 if (!scsi_target_queue_ready(shost, sdev))
1660 goto out_put_budget;
1661 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1662 goto out_dec_target_busy;
1663
1664 if (!(req->rq_flags & RQF_DONTPREP)) {
1665 ret = scsi_prepare_cmd(req);
1666 if (ret != BLK_STS_OK)
1667 goto out_dec_host_busy;
1668 req->rq_flags |= RQF_DONTPREP;
1669 } else {
1670 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1671 }
1672
1673 cmd->flags &= SCMD_PRESERVED_FLAGS;
1674 if (sdev->simple_tags)
1675 cmd->flags |= SCMD_TAGGED;
1676 if (bd->last)
1677 cmd->flags |= SCMD_LAST;
1678
1679 scsi_set_resid(cmd, 0);
1680 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1681 cmd->scsi_done = scsi_mq_done;
1682
1683 blk_mq_start_request(req);
1684 reason = scsi_dispatch_cmd(cmd);
1685 if (reason) {
1686 scsi_set_blocked(cmd, reason);
1687 ret = BLK_STS_RESOURCE;
1688 goto out_dec_host_busy;
1689 }
1690
1691 return BLK_STS_OK;
1692
1693out_dec_host_busy:
1694 scsi_dec_host_busy(shost, cmd);
1695out_dec_target_busy:
1696 if (scsi_target(sdev)->can_queue > 0)
1697 atomic_dec(&scsi_target(sdev)->target_busy);
1698out_put_budget:
1699 scsi_mq_put_budget(q, cmd->budget_token);
1700 cmd->budget_token = -1;
1701 switch (ret) {
1702 case BLK_STS_OK:
1703 break;
1704 case BLK_STS_RESOURCE:
1705 case BLK_STS_ZONE_RESOURCE:
1706 if (scsi_device_blocked(sdev))
1707 ret = BLK_STS_DEV_RESOURCE;
1708 break;
1709 case BLK_STS_AGAIN:
1710 scsi_req(req)->result = DID_BUS_BUSY << 16;
1711 if (req->rq_flags & RQF_DONTPREP)
1712 scsi_mq_uninit_cmd(cmd);
1713 break;
1714 default:
1715 if (unlikely(!scsi_device_online(sdev)))
1716 scsi_req(req)->result = DID_NO_CONNECT << 16;
1717 else
1718 scsi_req(req)->result = DID_ERROR << 16;
1719 /*
1720 * Make sure to release all allocated resources when
1721 * we hit an error, as we will never see this command
1722 * again.
1723 */
1724 if (req->rq_flags & RQF_DONTPREP)
1725 scsi_mq_uninit_cmd(cmd);
1726 scsi_run_queue_async(sdev);
1727 break;
1728 }
1729 return ret;
1730}
1731
1732static enum blk_eh_timer_return scsi_timeout(struct request *req,
1733 bool reserved)
1734{
1735 if (reserved)
1736 return BLK_EH_RESET_TIMER;
1737 return scsi_times_out(req);
1738}
1739
1740static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1741 unsigned int hctx_idx, unsigned int numa_node)
1742{
1743 struct Scsi_Host *shost = set->driver_data;
1744 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1745 struct scatterlist *sg;
1746 int ret = 0;
1747
1748 cmd->sense_buffer =
1749 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1750 if (!cmd->sense_buffer)
1751 return -ENOMEM;
1752 cmd->req.sense = cmd->sense_buffer;
1753
1754 if (scsi_host_get_prot(shost)) {
1755 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1756 shost->hostt->cmd_size;
1757 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1758 }
1759
1760 if (shost->hostt->init_cmd_priv) {
1761 ret = shost->hostt->init_cmd_priv(shost, cmd);
1762 if (ret < 0)
1763 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1764 }
1765
1766 return ret;
1767}
1768
1769static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1770 unsigned int hctx_idx)
1771{
1772 struct Scsi_Host *shost = set->driver_data;
1773 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1774
1775 if (shost->hostt->exit_cmd_priv)
1776 shost->hostt->exit_cmd_priv(shost, cmd);
1777 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1778}
1779
1780
1781static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
1782{
1783 struct Scsi_Host *shost = hctx->driver_data;
1784
1785 if (shost->hostt->mq_poll)
1786 return shost->hostt->mq_poll(shost, hctx->queue_num);
1787
1788 return 0;
1789}
1790
1791static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1792 unsigned int hctx_idx)
1793{
1794 struct Scsi_Host *shost = data;
1795
1796 hctx->driver_data = shost;
1797 return 0;
1798}
1799
1800static int scsi_map_queues(struct blk_mq_tag_set *set)
1801{
1802 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1803
1804 if (shost->hostt->map_queues)
1805 return shost->hostt->map_queues(shost);
1806 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1807}
1808
1809void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1810{
1811 struct device *dev = shost->dma_dev;
1812
1813 /*
1814 * this limit is imposed by hardware restrictions
1815 */
1816 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1817 SG_MAX_SEGMENTS));
1818
1819 if (scsi_host_prot_dma(shost)) {
1820 shost->sg_prot_tablesize =
1821 min_not_zero(shost->sg_prot_tablesize,
1822 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1823 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1824 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1825 }
1826
1827 if (dev->dma_mask) {
1828 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1829 dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1830 }
1831 blk_queue_max_hw_sectors(q, shost->max_sectors);
1832 blk_queue_segment_boundary(q, shost->dma_boundary);
1833 dma_set_seg_boundary(dev, shost->dma_boundary);
1834
1835 blk_queue_max_segment_size(q, shost->max_segment_size);
1836 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1837 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1838
1839 /*
1840 * Set a reasonable default alignment: The larger of 32-byte (dword),
1841 * which is a common minimum for HBAs, and the minimum DMA alignment,
1842 * which is set by the platform.
1843 *
1844 * Devices that require a bigger alignment can increase it later.
1845 */
1846 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1847}
1848EXPORT_SYMBOL_GPL(__scsi_init_queue);
1849
1850static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1851 .get_budget = scsi_mq_get_budget,
1852 .put_budget = scsi_mq_put_budget,
1853 .queue_rq = scsi_queue_rq,
1854 .complete = scsi_complete,
1855 .timeout = scsi_timeout,
1856#ifdef CONFIG_BLK_DEBUG_FS
1857 .show_rq = scsi_show_rq,
1858#endif
1859 .init_request = scsi_mq_init_request,
1860 .exit_request = scsi_mq_exit_request,
1861 .initialize_rq_fn = scsi_initialize_rq,
1862 .cleanup_rq = scsi_cleanup_rq,
1863 .busy = scsi_mq_lld_busy,
1864 .map_queues = scsi_map_queues,
1865 .init_hctx = scsi_init_hctx,
1866 .poll = scsi_mq_poll,
1867 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1868 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1869};
1870
1871
1872static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1873{
1874 struct Scsi_Host *shost = hctx->driver_data;
1875
1876 shost->hostt->commit_rqs(shost, hctx->queue_num);
1877}
1878
1879static const struct blk_mq_ops scsi_mq_ops = {
1880 .get_budget = scsi_mq_get_budget,
1881 .put_budget = scsi_mq_put_budget,
1882 .queue_rq = scsi_queue_rq,
1883 .commit_rqs = scsi_commit_rqs,
1884 .complete = scsi_complete,
1885 .timeout = scsi_timeout,
1886#ifdef CONFIG_BLK_DEBUG_FS
1887 .show_rq = scsi_show_rq,
1888#endif
1889 .init_request = scsi_mq_init_request,
1890 .exit_request = scsi_mq_exit_request,
1891 .initialize_rq_fn = scsi_initialize_rq,
1892 .cleanup_rq = scsi_cleanup_rq,
1893 .busy = scsi_mq_lld_busy,
1894 .map_queues = scsi_map_queues,
1895 .init_hctx = scsi_init_hctx,
1896 .poll = scsi_mq_poll,
1897 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1898 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1899};
1900
1901int scsi_mq_setup_tags(struct Scsi_Host *shost)
1902{
1903 unsigned int cmd_size, sgl_size;
1904 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1905
1906 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1907 scsi_mq_inline_sgl_size(shost));
1908 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1909 if (scsi_host_get_prot(shost))
1910 cmd_size += sizeof(struct scsi_data_buffer) +
1911 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1912
1913 memset(tag_set, 0, sizeof(*tag_set));
1914 if (shost->hostt->commit_rqs)
1915 tag_set->ops = &scsi_mq_ops;
1916 else
1917 tag_set->ops = &scsi_mq_ops_no_commit;
1918 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1919 tag_set->nr_maps = shost->nr_maps ? : 1;
1920 tag_set->queue_depth = shost->can_queue;
1921 tag_set->cmd_size = cmd_size;
1922 tag_set->numa_node = NUMA_NO_NODE;
1923 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1924 tag_set->flags |=
1925 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1926 tag_set->driver_data = shost;
1927 if (shost->host_tagset)
1928 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1929
1930 return blk_mq_alloc_tag_set(tag_set);
1931}
1932
1933void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1934{
1935 blk_mq_free_tag_set(&shost->tag_set);
1936}
1937
1938/**
1939 * scsi_device_from_queue - return sdev associated with a request_queue
1940 * @q: The request queue to return the sdev from
1941 *
1942 * Return the sdev associated with a request queue or NULL if the
1943 * request_queue does not reference a SCSI device.
1944 */
1945struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1946{
1947 struct scsi_device *sdev = NULL;
1948
1949 if (q->mq_ops == &scsi_mq_ops_no_commit ||
1950 q->mq_ops == &scsi_mq_ops)
1951 sdev = q->queuedata;
1952 if (!sdev || !get_device(&sdev->sdev_gendev))
1953 sdev = NULL;
1954
1955 return sdev;
1956}
1957
1958/**
1959 * scsi_block_requests - Utility function used by low-level drivers to prevent
1960 * further commands from being queued to the device.
1961 * @shost: host in question
1962 *
1963 * There is no timer nor any other means by which the requests get unblocked
1964 * other than the low-level driver calling scsi_unblock_requests().
1965 */
1966void scsi_block_requests(struct Scsi_Host *shost)
1967{
1968 shost->host_self_blocked = 1;
1969}
1970EXPORT_SYMBOL(scsi_block_requests);
1971
1972/**
1973 * scsi_unblock_requests - Utility function used by low-level drivers to allow
1974 * further commands to be queued to the device.
1975 * @shost: host in question
1976 *
1977 * There is no timer nor any other means by which the requests get unblocked
1978 * other than the low-level driver calling scsi_unblock_requests(). This is done
1979 * as an API function so that changes to the internals of the scsi mid-layer
1980 * won't require wholesale changes to drivers that use this feature.
1981 */
1982void scsi_unblock_requests(struct Scsi_Host *shost)
1983{
1984 shost->host_self_blocked = 0;
1985 scsi_run_host_queues(shost);
1986}
1987EXPORT_SYMBOL(scsi_unblock_requests);
1988
1989void scsi_exit_queue(void)
1990{
1991 kmem_cache_destroy(scsi_sense_cache);
1992}
1993
1994/**
1995 * scsi_mode_select - issue a mode select
1996 * @sdev: SCSI device to be queried
1997 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1998 * @sp: Save page bit (0 == don't save, 1 == save)
1999 * @modepage: mode page being requested
2000 * @buffer: request buffer (may not be smaller than eight bytes)
2001 * @len: length of request buffer.
2002 * @timeout: command timeout
2003 * @retries: number of retries before failing
2004 * @data: returns a structure abstracting the mode header data
2005 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2006 * must be SCSI_SENSE_BUFFERSIZE big.
2007 *
2008 * Returns zero if successful; negative error number or scsi
2009 * status on error
2010 *
2011 */
2012int
2013scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2014 unsigned char *buffer, int len, int timeout, int retries,
2015 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2016{
2017 unsigned char cmd[10];
2018 unsigned char *real_buffer;
2019 int ret;
2020
2021 memset(cmd, 0, sizeof(cmd));
2022 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2023
2024 if (sdev->use_10_for_ms) {
2025 if (len > 65535)
2026 return -EINVAL;
2027 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2028 if (!real_buffer)
2029 return -ENOMEM;
2030 memcpy(real_buffer + 8, buffer, len);
2031 len += 8;
2032 real_buffer[0] = 0;
2033 real_buffer[1] = 0;
2034 real_buffer[2] = data->medium_type;
2035 real_buffer[3] = data->device_specific;
2036 real_buffer[4] = data->longlba ? 0x01 : 0;
2037 real_buffer[5] = 0;
2038 real_buffer[6] = data->block_descriptor_length >> 8;
2039 real_buffer[7] = data->block_descriptor_length;
2040
2041 cmd[0] = MODE_SELECT_10;
2042 cmd[7] = len >> 8;
2043 cmd[8] = len;
2044 } else {
2045 if (len > 255 || data->block_descriptor_length > 255 ||
2046 data->longlba)
2047 return -EINVAL;
2048
2049 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2050 if (!real_buffer)
2051 return -ENOMEM;
2052 memcpy(real_buffer + 4, buffer, len);
2053 len += 4;
2054 real_buffer[0] = 0;
2055 real_buffer[1] = data->medium_type;
2056 real_buffer[2] = data->device_specific;
2057 real_buffer[3] = data->block_descriptor_length;
2058
2059 cmd[0] = MODE_SELECT;
2060 cmd[4] = len;
2061 }
2062
2063 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2064 sshdr, timeout, retries, NULL);
2065 kfree(real_buffer);
2066 return ret;
2067}
2068EXPORT_SYMBOL_GPL(scsi_mode_select);
2069
2070/**
2071 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2072 * @sdev: SCSI device to be queried
2073 * @dbd: set if mode sense will allow block descriptors to be returned
2074 * @modepage: mode page being requested
2075 * @buffer: request buffer (may not be smaller than eight bytes)
2076 * @len: length of request buffer.
2077 * @timeout: command timeout
2078 * @retries: number of retries before failing
2079 * @data: returns a structure abstracting the mode header data
2080 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2081 * must be SCSI_SENSE_BUFFERSIZE big.
2082 *
2083 * Returns zero if successful, or a negative error number on failure
2084 */
2085int
2086scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2087 unsigned char *buffer, int len, int timeout, int retries,
2088 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2089{
2090 unsigned char cmd[12];
2091 int use_10_for_ms;
2092 int header_length;
2093 int result, retry_count = retries;
2094 struct scsi_sense_hdr my_sshdr;
2095
2096 memset(data, 0, sizeof(*data));
2097 memset(&cmd[0], 0, 12);
2098
2099 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2100 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2101 cmd[2] = modepage;
2102
2103 /* caller might not be interested in sense, but we need it */
2104 if (!sshdr)
2105 sshdr = &my_sshdr;
2106
2107 retry:
2108 use_10_for_ms = sdev->use_10_for_ms;
2109
2110 if (use_10_for_ms) {
2111 if (len < 8)
2112 len = 8;
2113
2114 cmd[0] = MODE_SENSE_10;
2115 cmd[8] = len;
2116 header_length = 8;
2117 } else {
2118 if (len < 4)
2119 len = 4;
2120
2121 cmd[0] = MODE_SENSE;
2122 cmd[4] = len;
2123 header_length = 4;
2124 }
2125
2126 memset(buffer, 0, len);
2127
2128 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2129 sshdr, timeout, retries, NULL);
2130 if (result < 0)
2131 return result;
2132
2133 /* This code looks awful: what it's doing is making sure an
2134 * ILLEGAL REQUEST sense return identifies the actual command
2135 * byte as the problem. MODE_SENSE commands can return
2136 * ILLEGAL REQUEST if the code page isn't supported */
2137
2138 if (!scsi_status_is_good(result)) {
2139 if (scsi_sense_valid(sshdr)) {
2140 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2141 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2142 /*
2143 * Invalid command operation code
2144 */
2145 if (use_10_for_ms) {
2146 sdev->use_10_for_ms = 0;
2147 goto retry;
2148 }
2149 }
2150 if (scsi_status_is_check_condition(result) &&
2151 sshdr->sense_key == UNIT_ATTENTION &&
2152 retry_count) {
2153 retry_count--;
2154 goto retry;
2155 }
2156 }
2157 return -EIO;
2158 }
2159 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2160 (modepage == 6 || modepage == 8))) {
2161 /* Initio breakage? */
2162 header_length = 0;
2163 data->length = 13;
2164 data->medium_type = 0;
2165 data->device_specific = 0;
2166 data->longlba = 0;
2167 data->block_descriptor_length = 0;
2168 } else if (use_10_for_ms) {
2169 data->length = buffer[0]*256 + buffer[1] + 2;
2170 data->medium_type = buffer[2];
2171 data->device_specific = buffer[3];
2172 data->longlba = buffer[4] & 0x01;
2173 data->block_descriptor_length = buffer[6]*256
2174 + buffer[7];
2175 } else {
2176 data->length = buffer[0] + 1;
2177 data->medium_type = buffer[1];
2178 data->device_specific = buffer[2];
2179 data->block_descriptor_length = buffer[3];
2180 }
2181 data->header_length = header_length;
2182
2183 return 0;
2184}
2185EXPORT_SYMBOL(scsi_mode_sense);
2186
2187/**
2188 * scsi_test_unit_ready - test if unit is ready
2189 * @sdev: scsi device to change the state of.
2190 * @timeout: command timeout
2191 * @retries: number of retries before failing
2192 * @sshdr: outpout pointer for decoded sense information.
2193 *
2194 * Returns zero if unsuccessful or an error if TUR failed. For
2195 * removable media, UNIT_ATTENTION sets ->changed flag.
2196 **/
2197int
2198scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2199 struct scsi_sense_hdr *sshdr)
2200{
2201 char cmd[] = {
2202 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2203 };
2204 int result;
2205
2206 /* try to eat the UNIT_ATTENTION if there are enough retries */
2207 do {
2208 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2209 timeout, 1, NULL);
2210 if (sdev->removable && scsi_sense_valid(sshdr) &&
2211 sshdr->sense_key == UNIT_ATTENTION)
2212 sdev->changed = 1;
2213 } while (scsi_sense_valid(sshdr) &&
2214 sshdr->sense_key == UNIT_ATTENTION && --retries);
2215
2216 return result;
2217}
2218EXPORT_SYMBOL(scsi_test_unit_ready);
2219
2220/**
2221 * scsi_device_set_state - Take the given device through the device state model.
2222 * @sdev: scsi device to change the state of.
2223 * @state: state to change to.
2224 *
2225 * Returns zero if successful or an error if the requested
2226 * transition is illegal.
2227 */
2228int
2229scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2230{
2231 enum scsi_device_state oldstate = sdev->sdev_state;
2232
2233 if (state == oldstate)
2234 return 0;
2235
2236 switch (state) {
2237 case SDEV_CREATED:
2238 switch (oldstate) {
2239 case SDEV_CREATED_BLOCK:
2240 break;
2241 default:
2242 goto illegal;
2243 }
2244 break;
2245
2246 case SDEV_RUNNING:
2247 switch (oldstate) {
2248 case SDEV_CREATED:
2249 case SDEV_OFFLINE:
2250 case SDEV_TRANSPORT_OFFLINE:
2251 case SDEV_QUIESCE:
2252 case SDEV_BLOCK:
2253 break;
2254 default:
2255 goto illegal;
2256 }
2257 break;
2258
2259 case SDEV_QUIESCE:
2260 switch (oldstate) {
2261 case SDEV_RUNNING:
2262 case SDEV_OFFLINE:
2263 case SDEV_TRANSPORT_OFFLINE:
2264 break;
2265 default:
2266 goto illegal;
2267 }
2268 break;
2269
2270 case SDEV_OFFLINE:
2271 case SDEV_TRANSPORT_OFFLINE:
2272 switch (oldstate) {
2273 case SDEV_CREATED:
2274 case SDEV_RUNNING:
2275 case SDEV_QUIESCE:
2276 case SDEV_BLOCK:
2277 break;
2278 default:
2279 goto illegal;
2280 }
2281 break;
2282
2283 case SDEV_BLOCK:
2284 switch (oldstate) {
2285 case SDEV_RUNNING:
2286 case SDEV_CREATED_BLOCK:
2287 case SDEV_QUIESCE:
2288 case SDEV_OFFLINE:
2289 break;
2290 default:
2291 goto illegal;
2292 }
2293 break;
2294
2295 case SDEV_CREATED_BLOCK:
2296 switch (oldstate) {
2297 case SDEV_CREATED:
2298 break;
2299 default:
2300 goto illegal;
2301 }
2302 break;
2303
2304 case SDEV_CANCEL:
2305 switch (oldstate) {
2306 case SDEV_CREATED:
2307 case SDEV_RUNNING:
2308 case SDEV_QUIESCE:
2309 case SDEV_OFFLINE:
2310 case SDEV_TRANSPORT_OFFLINE:
2311 break;
2312 default:
2313 goto illegal;
2314 }
2315 break;
2316
2317 case SDEV_DEL:
2318 switch (oldstate) {
2319 case SDEV_CREATED:
2320 case SDEV_RUNNING:
2321 case SDEV_OFFLINE:
2322 case SDEV_TRANSPORT_OFFLINE:
2323 case SDEV_CANCEL:
2324 case SDEV_BLOCK:
2325 case SDEV_CREATED_BLOCK:
2326 break;
2327 default:
2328 goto illegal;
2329 }
2330 break;
2331
2332 }
2333 sdev->offline_already = false;
2334 sdev->sdev_state = state;
2335 return 0;
2336
2337 illegal:
2338 SCSI_LOG_ERROR_RECOVERY(1,
2339 sdev_printk(KERN_ERR, sdev,
2340 "Illegal state transition %s->%s",
2341 scsi_device_state_name(oldstate),
2342 scsi_device_state_name(state))
2343 );
2344 return -EINVAL;
2345}
2346EXPORT_SYMBOL(scsi_device_set_state);
2347
2348/**
2349 * scsi_evt_emit - emit a single SCSI device uevent
2350 * @sdev: associated SCSI device
2351 * @evt: event to emit
2352 *
2353 * Send a single uevent (scsi_event) to the associated scsi_device.
2354 */
2355static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2356{
2357 int idx = 0;
2358 char *envp[3];
2359
2360 switch (evt->evt_type) {
2361 case SDEV_EVT_MEDIA_CHANGE:
2362 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2363 break;
2364 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2365 scsi_rescan_device(&sdev->sdev_gendev);
2366 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2367 break;
2368 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2369 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2370 break;
2371 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2372 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2373 break;
2374 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2375 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2376 break;
2377 case SDEV_EVT_LUN_CHANGE_REPORTED:
2378 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2379 break;
2380 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2381 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2382 break;
2383 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2384 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2385 break;
2386 default:
2387 /* do nothing */
2388 break;
2389 }
2390
2391 envp[idx++] = NULL;
2392
2393 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2394}
2395
2396/**
2397 * scsi_evt_thread - send a uevent for each scsi event
2398 * @work: work struct for scsi_device
2399 *
2400 * Dispatch queued events to their associated scsi_device kobjects
2401 * as uevents.
2402 */
2403void scsi_evt_thread(struct work_struct *work)
2404{
2405 struct scsi_device *sdev;
2406 enum scsi_device_event evt_type;
2407 LIST_HEAD(event_list);
2408
2409 sdev = container_of(work, struct scsi_device, event_work);
2410
2411 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2412 if (test_and_clear_bit(evt_type, sdev->pending_events))
2413 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2414
2415 while (1) {
2416 struct scsi_event *evt;
2417 struct list_head *this, *tmp;
2418 unsigned long flags;
2419
2420 spin_lock_irqsave(&sdev->list_lock, flags);
2421 list_splice_init(&sdev->event_list, &event_list);
2422 spin_unlock_irqrestore(&sdev->list_lock, flags);
2423
2424 if (list_empty(&event_list))
2425 break;
2426
2427 list_for_each_safe(this, tmp, &event_list) {
2428 evt = list_entry(this, struct scsi_event, node);
2429 list_del(&evt->node);
2430 scsi_evt_emit(sdev, evt);
2431 kfree(evt);
2432 }
2433 }
2434}
2435
2436/**
2437 * sdev_evt_send - send asserted event to uevent thread
2438 * @sdev: scsi_device event occurred on
2439 * @evt: event to send
2440 *
2441 * Assert scsi device event asynchronously.
2442 */
2443void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2444{
2445 unsigned long flags;
2446
2447#if 0
2448 /* FIXME: currently this check eliminates all media change events
2449 * for polled devices. Need to update to discriminate between AN
2450 * and polled events */
2451 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2452 kfree(evt);
2453 return;
2454 }
2455#endif
2456
2457 spin_lock_irqsave(&sdev->list_lock, flags);
2458 list_add_tail(&evt->node, &sdev->event_list);
2459 schedule_work(&sdev->event_work);
2460 spin_unlock_irqrestore(&sdev->list_lock, flags);
2461}
2462EXPORT_SYMBOL_GPL(sdev_evt_send);
2463
2464/**
2465 * sdev_evt_alloc - allocate a new scsi event
2466 * @evt_type: type of event to allocate
2467 * @gfpflags: GFP flags for allocation
2468 *
2469 * Allocates and returns a new scsi_event.
2470 */
2471struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2472 gfp_t gfpflags)
2473{
2474 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2475 if (!evt)
2476 return NULL;
2477
2478 evt->evt_type = evt_type;
2479 INIT_LIST_HEAD(&evt->node);
2480
2481 /* evt_type-specific initialization, if any */
2482 switch (evt_type) {
2483 case SDEV_EVT_MEDIA_CHANGE:
2484 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2485 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2486 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2487 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2488 case SDEV_EVT_LUN_CHANGE_REPORTED:
2489 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2490 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2491 default:
2492 /* do nothing */
2493 break;
2494 }
2495
2496 return evt;
2497}
2498EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2499
2500/**
2501 * sdev_evt_send_simple - send asserted event to uevent thread
2502 * @sdev: scsi_device event occurred on
2503 * @evt_type: type of event to send
2504 * @gfpflags: GFP flags for allocation
2505 *
2506 * Assert scsi device event asynchronously, given an event type.
2507 */
2508void sdev_evt_send_simple(struct scsi_device *sdev,
2509 enum scsi_device_event evt_type, gfp_t gfpflags)
2510{
2511 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2512 if (!evt) {
2513 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2514 evt_type);
2515 return;
2516 }
2517
2518 sdev_evt_send(sdev, evt);
2519}
2520EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2521
2522/**
2523 * scsi_device_quiesce - Block all commands except power management.
2524 * @sdev: scsi device to quiesce.
2525 *
2526 * This works by trying to transition to the SDEV_QUIESCE state
2527 * (which must be a legal transition). When the device is in this
2528 * state, only power management requests will be accepted, all others will
2529 * be deferred.
2530 *
2531 * Must be called with user context, may sleep.
2532 *
2533 * Returns zero if unsuccessful or an error if not.
2534 */
2535int
2536scsi_device_quiesce(struct scsi_device *sdev)
2537{
2538 struct request_queue *q = sdev->request_queue;
2539 int err;
2540
2541 /*
2542 * It is allowed to call scsi_device_quiesce() multiple times from
2543 * the same context but concurrent scsi_device_quiesce() calls are
2544 * not allowed.
2545 */
2546 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2547
2548 if (sdev->quiesced_by == current)
2549 return 0;
2550
2551 blk_set_pm_only(q);
2552
2553 blk_mq_freeze_queue(q);
2554 /*
2555 * Ensure that the effect of blk_set_pm_only() will be visible
2556 * for percpu_ref_tryget() callers that occur after the queue
2557 * unfreeze even if the queue was already frozen before this function
2558 * was called. See also https://lwn.net/Articles/573497/.
2559 */
2560 synchronize_rcu();
2561 blk_mq_unfreeze_queue(q);
2562
2563 mutex_lock(&sdev->state_mutex);
2564 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2565 if (err == 0)
2566 sdev->quiesced_by = current;
2567 else
2568 blk_clear_pm_only(q);
2569 mutex_unlock(&sdev->state_mutex);
2570
2571 return err;
2572}
2573EXPORT_SYMBOL(scsi_device_quiesce);
2574
2575/**
2576 * scsi_device_resume - Restart user issued commands to a quiesced device.
2577 * @sdev: scsi device to resume.
2578 *
2579 * Moves the device from quiesced back to running and restarts the
2580 * queues.
2581 *
2582 * Must be called with user context, may sleep.
2583 */
2584void scsi_device_resume(struct scsi_device *sdev)
2585{
2586 /* check if the device state was mutated prior to resume, and if
2587 * so assume the state is being managed elsewhere (for example
2588 * device deleted during suspend)
2589 */
2590 mutex_lock(&sdev->state_mutex);
2591 if (sdev->sdev_state == SDEV_QUIESCE)
2592 scsi_device_set_state(sdev, SDEV_RUNNING);
2593 if (sdev->quiesced_by) {
2594 sdev->quiesced_by = NULL;
2595 blk_clear_pm_only(sdev->request_queue);
2596 }
2597 mutex_unlock(&sdev->state_mutex);
2598}
2599EXPORT_SYMBOL(scsi_device_resume);
2600
2601static void
2602device_quiesce_fn(struct scsi_device *sdev, void *data)
2603{
2604 scsi_device_quiesce(sdev);
2605}
2606
2607void
2608scsi_target_quiesce(struct scsi_target *starget)
2609{
2610 starget_for_each_device(starget, NULL, device_quiesce_fn);
2611}
2612EXPORT_SYMBOL(scsi_target_quiesce);
2613
2614static void
2615device_resume_fn(struct scsi_device *sdev, void *data)
2616{
2617 scsi_device_resume(sdev);
2618}
2619
2620void
2621scsi_target_resume(struct scsi_target *starget)
2622{
2623 starget_for_each_device(starget, NULL, device_resume_fn);
2624}
2625EXPORT_SYMBOL(scsi_target_resume);
2626
2627/**
2628 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2629 * @sdev: device to block
2630 *
2631 * Pause SCSI command processing on the specified device. Does not sleep.
2632 *
2633 * Returns zero if successful or a negative error code upon failure.
2634 *
2635 * Notes:
2636 * This routine transitions the device to the SDEV_BLOCK state (which must be
2637 * a legal transition). When the device is in this state, command processing
2638 * is paused until the device leaves the SDEV_BLOCK state. See also
2639 * scsi_internal_device_unblock_nowait().
2640 */
2641int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2642{
2643 struct request_queue *q = sdev->request_queue;
2644 int err = 0;
2645
2646 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2647 if (err) {
2648 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2649
2650 if (err)
2651 return err;
2652 }
2653
2654 /*
2655 * The device has transitioned to SDEV_BLOCK. Stop the
2656 * block layer from calling the midlayer with this device's
2657 * request queue.
2658 */
2659 blk_mq_quiesce_queue_nowait(q);
2660 return 0;
2661}
2662EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2663
2664/**
2665 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2666 * @sdev: device to block
2667 *
2668 * Pause SCSI command processing on the specified device and wait until all
2669 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2670 *
2671 * Returns zero if successful or a negative error code upon failure.
2672 *
2673 * Note:
2674 * This routine transitions the device to the SDEV_BLOCK state (which must be
2675 * a legal transition). When the device is in this state, command processing
2676 * is paused until the device leaves the SDEV_BLOCK state. See also
2677 * scsi_internal_device_unblock().
2678 */
2679static int scsi_internal_device_block(struct scsi_device *sdev)
2680{
2681 struct request_queue *q = sdev->request_queue;
2682 int err;
2683
2684 mutex_lock(&sdev->state_mutex);
2685 err = scsi_internal_device_block_nowait(sdev);
2686 if (err == 0)
2687 blk_mq_quiesce_queue(q);
2688 mutex_unlock(&sdev->state_mutex);
2689
2690 return err;
2691}
2692
2693void scsi_start_queue(struct scsi_device *sdev)
2694{
2695 struct request_queue *q = sdev->request_queue;
2696
2697 blk_mq_unquiesce_queue(q);
2698}
2699
2700/**
2701 * scsi_internal_device_unblock_nowait - resume a device after a block request
2702 * @sdev: device to resume
2703 * @new_state: state to set the device to after unblocking
2704 *
2705 * Restart the device queue for a previously suspended SCSI device. Does not
2706 * sleep.
2707 *
2708 * Returns zero if successful or a negative error code upon failure.
2709 *
2710 * Notes:
2711 * This routine transitions the device to the SDEV_RUNNING state or to one of
2712 * the offline states (which must be a legal transition) allowing the midlayer
2713 * to goose the queue for this device.
2714 */
2715int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2716 enum scsi_device_state new_state)
2717{
2718 switch (new_state) {
2719 case SDEV_RUNNING:
2720 case SDEV_TRANSPORT_OFFLINE:
2721 break;
2722 default:
2723 return -EINVAL;
2724 }
2725
2726 /*
2727 * Try to transition the scsi device to SDEV_RUNNING or one of the
2728 * offlined states and goose the device queue if successful.
2729 */
2730 switch (sdev->sdev_state) {
2731 case SDEV_BLOCK:
2732 case SDEV_TRANSPORT_OFFLINE:
2733 sdev->sdev_state = new_state;
2734 break;
2735 case SDEV_CREATED_BLOCK:
2736 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2737 new_state == SDEV_OFFLINE)
2738 sdev->sdev_state = new_state;
2739 else
2740 sdev->sdev_state = SDEV_CREATED;
2741 break;
2742 case SDEV_CANCEL:
2743 case SDEV_OFFLINE:
2744 break;
2745 default:
2746 return -EINVAL;
2747 }
2748 scsi_start_queue(sdev);
2749
2750 return 0;
2751}
2752EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2753
2754/**
2755 * scsi_internal_device_unblock - resume a device after a block request
2756 * @sdev: device to resume
2757 * @new_state: state to set the device to after unblocking
2758 *
2759 * Restart the device queue for a previously suspended SCSI device. May sleep.
2760 *
2761 * Returns zero if successful or a negative error code upon failure.
2762 *
2763 * Notes:
2764 * This routine transitions the device to the SDEV_RUNNING state or to one of
2765 * the offline states (which must be a legal transition) allowing the midlayer
2766 * to goose the queue for this device.
2767 */
2768static int scsi_internal_device_unblock(struct scsi_device *sdev,
2769 enum scsi_device_state new_state)
2770{
2771 int ret;
2772
2773 mutex_lock(&sdev->state_mutex);
2774 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2775 mutex_unlock(&sdev->state_mutex);
2776
2777 return ret;
2778}
2779
2780static void
2781device_block(struct scsi_device *sdev, void *data)
2782{
2783 int ret;
2784
2785 ret = scsi_internal_device_block(sdev);
2786
2787 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2788 dev_name(&sdev->sdev_gendev), ret);
2789}
2790
2791static int
2792target_block(struct device *dev, void *data)
2793{
2794 if (scsi_is_target_device(dev))
2795 starget_for_each_device(to_scsi_target(dev), NULL,
2796 device_block);
2797 return 0;
2798}
2799
2800void
2801scsi_target_block(struct device *dev)
2802{
2803 if (scsi_is_target_device(dev))
2804 starget_for_each_device(to_scsi_target(dev), NULL,
2805 device_block);
2806 else
2807 device_for_each_child(dev, NULL, target_block);
2808}
2809EXPORT_SYMBOL_GPL(scsi_target_block);
2810
2811static void
2812device_unblock(struct scsi_device *sdev, void *data)
2813{
2814 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2815}
2816
2817static int
2818target_unblock(struct device *dev, void *data)
2819{
2820 if (scsi_is_target_device(dev))
2821 starget_for_each_device(to_scsi_target(dev), data,
2822 device_unblock);
2823 return 0;
2824}
2825
2826void
2827scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2828{
2829 if (scsi_is_target_device(dev))
2830 starget_for_each_device(to_scsi_target(dev), &new_state,
2831 device_unblock);
2832 else
2833 device_for_each_child(dev, &new_state, target_unblock);
2834}
2835EXPORT_SYMBOL_GPL(scsi_target_unblock);
2836
2837int
2838scsi_host_block(struct Scsi_Host *shost)
2839{
2840 struct scsi_device *sdev;
2841 int ret = 0;
2842
2843 /*
2844 * Call scsi_internal_device_block_nowait so we can avoid
2845 * calling synchronize_rcu() for each LUN.
2846 */
2847 shost_for_each_device(sdev, shost) {
2848 mutex_lock(&sdev->state_mutex);
2849 ret = scsi_internal_device_block_nowait(sdev);
2850 mutex_unlock(&sdev->state_mutex);
2851 if (ret) {
2852 scsi_device_put(sdev);
2853 break;
2854 }
2855 }
2856
2857 /*
2858 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2859 * calling synchronize_rcu() once is enough.
2860 */
2861 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2862
2863 if (!ret)
2864 synchronize_rcu();
2865
2866 return ret;
2867}
2868EXPORT_SYMBOL_GPL(scsi_host_block);
2869
2870int
2871scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2872{
2873 struct scsi_device *sdev;
2874 int ret = 0;
2875
2876 shost_for_each_device(sdev, shost) {
2877 ret = scsi_internal_device_unblock(sdev, new_state);
2878 if (ret) {
2879 scsi_device_put(sdev);
2880 break;
2881 }
2882 }
2883 return ret;
2884}
2885EXPORT_SYMBOL_GPL(scsi_host_unblock);
2886
2887/**
2888 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2889 * @sgl: scatter-gather list
2890 * @sg_count: number of segments in sg
2891 * @offset: offset in bytes into sg, on return offset into the mapped area
2892 * @len: bytes to map, on return number of bytes mapped
2893 *
2894 * Returns virtual address of the start of the mapped page
2895 */
2896void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2897 size_t *offset, size_t *len)
2898{
2899 int i;
2900 size_t sg_len = 0, len_complete = 0;
2901 struct scatterlist *sg;
2902 struct page *page;
2903
2904 WARN_ON(!irqs_disabled());
2905
2906 for_each_sg(sgl, sg, sg_count, i) {
2907 len_complete = sg_len; /* Complete sg-entries */
2908 sg_len += sg->length;
2909 if (sg_len > *offset)
2910 break;
2911 }
2912
2913 if (unlikely(i == sg_count)) {
2914 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2915 "elements %d\n",
2916 __func__, sg_len, *offset, sg_count);
2917 WARN_ON(1);
2918 return NULL;
2919 }
2920
2921 /* Offset starting from the beginning of first page in this sg-entry */
2922 *offset = *offset - len_complete + sg->offset;
2923
2924 /* Assumption: contiguous pages can be accessed as "page + i" */
2925 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2926 *offset &= ~PAGE_MASK;
2927
2928 /* Bytes in this sg-entry from *offset to the end of the page */
2929 sg_len = PAGE_SIZE - *offset;
2930 if (*len > sg_len)
2931 *len = sg_len;
2932
2933 return kmap_atomic(page);
2934}
2935EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2936
2937/**
2938 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2939 * @virt: virtual address to be unmapped
2940 */
2941void scsi_kunmap_atomic_sg(void *virt)
2942{
2943 kunmap_atomic(virt);
2944}
2945EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2946
2947void sdev_disable_disk_events(struct scsi_device *sdev)
2948{
2949 atomic_inc(&sdev->disk_events_disable_depth);
2950}
2951EXPORT_SYMBOL(sdev_disable_disk_events);
2952
2953void sdev_enable_disk_events(struct scsi_device *sdev)
2954{
2955 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2956 return;
2957 atomic_dec(&sdev->disk_events_disable_depth);
2958}
2959EXPORT_SYMBOL(sdev_enable_disk_events);
2960
2961static unsigned char designator_prio(const unsigned char *d)
2962{
2963 if (d[1] & 0x30)
2964 /* not associated with LUN */
2965 return 0;
2966
2967 if (d[3] == 0)
2968 /* invalid length */
2969 return 0;
2970
2971 /*
2972 * Order of preference for lun descriptor:
2973 * - SCSI name string
2974 * - NAA IEEE Registered Extended
2975 * - EUI-64 based 16-byte
2976 * - EUI-64 based 12-byte
2977 * - NAA IEEE Registered
2978 * - NAA IEEE Extended
2979 * - EUI-64 based 8-byte
2980 * - SCSI name string (truncated)
2981 * - T10 Vendor ID
2982 * as longer descriptors reduce the likelyhood
2983 * of identification clashes.
2984 */
2985
2986 switch (d[1] & 0xf) {
2987 case 8:
2988 /* SCSI name string, variable-length UTF-8 */
2989 return 9;
2990 case 3:
2991 switch (d[4] >> 4) {
2992 case 6:
2993 /* NAA registered extended */
2994 return 8;
2995 case 5:
2996 /* NAA registered */
2997 return 5;
2998 case 4:
2999 /* NAA extended */
3000 return 4;
3001 case 3:
3002 /* NAA locally assigned */
3003 return 1;
3004 default:
3005 break;
3006 }
3007 break;
3008 case 2:
3009 switch (d[3]) {
3010 case 16:
3011 /* EUI64-based, 16 byte */
3012 return 7;
3013 case 12:
3014 /* EUI64-based, 12 byte */
3015 return 6;
3016 case 8:
3017 /* EUI64-based, 8 byte */
3018 return 3;
3019 default:
3020 break;
3021 }
3022 break;
3023 case 1:
3024 /* T10 vendor ID */
3025 return 1;
3026 default:
3027 break;
3028 }
3029
3030 return 0;
3031}
3032
3033/**
3034 * scsi_vpd_lun_id - return a unique device identification
3035 * @sdev: SCSI device
3036 * @id: buffer for the identification
3037 * @id_len: length of the buffer
3038 *
3039 * Copies a unique device identification into @id based
3040 * on the information in the VPD page 0x83 of the device.
3041 * The string will be formatted as a SCSI name string.
3042 *
3043 * Returns the length of the identification or error on failure.
3044 * If the identifier is longer than the supplied buffer the actual
3045 * identifier length is returned and the buffer is not zero-padded.
3046 */
3047int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3048{
3049 u8 cur_id_prio = 0;
3050 u8 cur_id_size = 0;
3051 const unsigned char *d, *cur_id_str;
3052 const struct scsi_vpd *vpd_pg83;
3053 int id_size = -EINVAL;
3054
3055 rcu_read_lock();
3056 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3057 if (!vpd_pg83) {
3058 rcu_read_unlock();
3059 return -ENXIO;
3060 }
3061
3062 /* The id string must be at least 20 bytes + terminating NULL byte */
3063 if (id_len < 21) {
3064 rcu_read_unlock();
3065 return -EINVAL;
3066 }
3067
3068 memset(id, 0, id_len);
3069 for (d = vpd_pg83->data + 4;
3070 d < vpd_pg83->data + vpd_pg83->len;
3071 d += d[3] + 4) {
3072 u8 prio = designator_prio(d);
3073
3074 if (prio == 0 || cur_id_prio > prio)
3075 continue;
3076
3077 switch (d[1] & 0xf) {
3078 case 0x1:
3079 /* T10 Vendor ID */
3080 if (cur_id_size > d[3])
3081 break;
3082 cur_id_prio = prio;
3083 cur_id_size = d[3];
3084 if (cur_id_size + 4 > id_len)
3085 cur_id_size = id_len - 4;
3086 cur_id_str = d + 4;
3087 id_size = snprintf(id, id_len, "t10.%*pE",
3088 cur_id_size, cur_id_str);
3089 break;
3090 case 0x2:
3091 /* EUI-64 */
3092 cur_id_prio = prio;
3093 cur_id_size = d[3];
3094 cur_id_str = d + 4;
3095 switch (cur_id_size) {
3096 case 8:
3097 id_size = snprintf(id, id_len,
3098 "eui.%8phN",
3099 cur_id_str);
3100 break;
3101 case 12:
3102 id_size = snprintf(id, id_len,
3103 "eui.%12phN",
3104 cur_id_str);
3105 break;
3106 case 16:
3107 id_size = snprintf(id, id_len,
3108 "eui.%16phN",
3109 cur_id_str);
3110 break;
3111 default:
3112 break;
3113 }
3114 break;
3115 case 0x3:
3116 /* NAA */
3117 cur_id_prio = prio;
3118 cur_id_size = d[3];
3119 cur_id_str = d + 4;
3120 switch (cur_id_size) {
3121 case 8:
3122 id_size = snprintf(id, id_len,
3123 "naa.%8phN",
3124 cur_id_str);
3125 break;
3126 case 16:
3127 id_size = snprintf(id, id_len,
3128 "naa.%16phN",
3129 cur_id_str);
3130 break;
3131 default:
3132 break;
3133 }
3134 break;
3135 case 0x8:
3136 /* SCSI name string */
3137 if (cur_id_size > d[3])
3138 break;
3139 /* Prefer others for truncated descriptor */
3140 if (d[3] > id_len) {
3141 prio = 2;
3142 if (cur_id_prio > prio)
3143 break;
3144 }
3145 cur_id_prio = prio;
3146 cur_id_size = id_size = d[3];
3147 cur_id_str = d + 4;
3148 if (cur_id_size >= id_len)
3149 cur_id_size = id_len - 1;
3150 memcpy(id, cur_id_str, cur_id_size);
3151 break;
3152 default:
3153 break;
3154 }
3155 }
3156 rcu_read_unlock();
3157
3158 return id_size;
3159}
3160EXPORT_SYMBOL(scsi_vpd_lun_id);
3161
3162/*
3163 * scsi_vpd_tpg_id - return a target port group identifier
3164 * @sdev: SCSI device
3165 *
3166 * Returns the Target Port Group identifier from the information
3167 * froom VPD page 0x83 of the device.
3168 *
3169 * Returns the identifier or error on failure.
3170 */
3171int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3172{
3173 const unsigned char *d;
3174 const struct scsi_vpd *vpd_pg83;
3175 int group_id = -EAGAIN, rel_port = -1;
3176
3177 rcu_read_lock();
3178 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3179 if (!vpd_pg83) {
3180 rcu_read_unlock();
3181 return -ENXIO;
3182 }
3183
3184 d = vpd_pg83->data + 4;
3185 while (d < vpd_pg83->data + vpd_pg83->len) {
3186 switch (d[1] & 0xf) {
3187 case 0x4:
3188 /* Relative target port */
3189 rel_port = get_unaligned_be16(&d[6]);
3190 break;
3191 case 0x5:
3192 /* Target port group */
3193 group_id = get_unaligned_be16(&d[6]);
3194 break;
3195 default:
3196 break;
3197 }
3198 d += d[3] + 4;
3199 }
3200 rcu_read_unlock();
3201
3202 if (group_id >= 0 && rel_id && rel_port != -1)
3203 *rel_id = rel_port;
3204
3205 return group_id;
3206}
3207EXPORT_SYMBOL(scsi_vpd_tpg_id);
3208
3209/**
3210 * scsi_build_sense - build sense data for a command
3211 * @scmd: scsi command for which the sense should be formatted
3212 * @desc: Sense format (non-zero == descriptor format,
3213 * 0 == fixed format)
3214 * @key: Sense key
3215 * @asc: Additional sense code
3216 * @ascq: Additional sense code qualifier
3217 *
3218 **/
3219void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3220{
3221 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3222 scmd->result = SAM_STAT_CHECK_CONDITION;
3223}
3224EXPORT_SYMBOL_GPL(scsi_build_sense);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12#include <linux/bio.h>
13#include <linux/bitops.h>
14#include <linux/blkdev.h>
15#include <linux/completion.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
21#include <linux/hardirq.h>
22#include <linux/scatterlist.h>
23#include <linux/blk-mq.h>
24#include <linux/blk-integrity.h>
25#include <linux/ratelimit.h>
26#include <asm/unaligned.h>
27
28#include <scsi/scsi.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_dbg.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_driver.h>
33#include <scsi/scsi_eh.h>
34#include <scsi/scsi_host.h>
35#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
36#include <scsi/scsi_dh.h>
37
38#include <trace/events/scsi.h>
39
40#include "scsi_debugfs.h"
41#include "scsi_priv.h"
42#include "scsi_logging.h"
43
44/*
45 * Size of integrity metadata is usually small, 1 inline sg should
46 * cover normal cases.
47 */
48#ifdef CONFIG_ARCH_NO_SG_CHAIN
49#define SCSI_INLINE_PROT_SG_CNT 0
50#define SCSI_INLINE_SG_CNT 0
51#else
52#define SCSI_INLINE_PROT_SG_CNT 1
53#define SCSI_INLINE_SG_CNT 2
54#endif
55
56static struct kmem_cache *scsi_sense_cache;
57static DEFINE_MUTEX(scsi_sense_cache_mutex);
58
59static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60
61int scsi_init_sense_cache(struct Scsi_Host *shost)
62{
63 int ret = 0;
64
65 mutex_lock(&scsi_sense_cache_mutex);
66 if (!scsi_sense_cache) {
67 scsi_sense_cache =
68 kmem_cache_create_usercopy("scsi_sense_cache",
69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 0, SCSI_SENSE_BUFFERSIZE, NULL);
71 if (!scsi_sense_cache)
72 ret = -ENOMEM;
73 }
74 mutex_unlock(&scsi_sense_cache_mutex);
75 return ret;
76}
77
78static void
79scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80{
81 struct Scsi_Host *host = cmd->device->host;
82 struct scsi_device *device = cmd->device;
83 struct scsi_target *starget = scsi_target(device);
84
85 /*
86 * Set the appropriate busy bit for the device/host.
87 *
88 * If the host/device isn't busy, assume that something actually
89 * completed, and that we should be able to queue a command now.
90 *
91 * Note that the prior mid-layer assumption that any host could
92 * always queue at least one command is now broken. The mid-layer
93 * will implement a user specifiable stall (see
94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 * if a command is requeued with no other commands outstanding
96 * either for the device or for the host.
97 */
98 switch (reason) {
99 case SCSI_MLQUEUE_HOST_BUSY:
100 atomic_set(&host->host_blocked, host->max_host_blocked);
101 break;
102 case SCSI_MLQUEUE_DEVICE_BUSY:
103 case SCSI_MLQUEUE_EH_RETRY:
104 atomic_set(&device->device_blocked,
105 device->max_device_blocked);
106 break;
107 case SCSI_MLQUEUE_TARGET_BUSY:
108 atomic_set(&starget->target_blocked,
109 starget->max_target_blocked);
110 break;
111 }
112}
113
114static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115{
116 struct request *rq = scsi_cmd_to_rq(cmd);
117
118 if (rq->rq_flags & RQF_DONTPREP) {
119 rq->rq_flags &= ~RQF_DONTPREP;
120 scsi_mq_uninit_cmd(cmd);
121 } else {
122 WARN_ON_ONCE(true);
123 }
124
125 if (msecs) {
126 blk_mq_requeue_request(rq, false);
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128 } else
129 blk_mq_requeue_request(rq, true);
130}
131
132/**
133 * __scsi_queue_insert - private queue insertion
134 * @cmd: The SCSI command being requeued
135 * @reason: The reason for the requeue
136 * @unbusy: Whether the queue should be unbusied
137 *
138 * This is a private queue insertion. The public interface
139 * scsi_queue_insert() always assumes the queue should be unbusied
140 * because it's always called before the completion. This function is
141 * for a requeue after completion, which should only occur in this
142 * file.
143 */
144static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
145{
146 struct scsi_device *device = cmd->device;
147
148 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
149 "Inserting command %p into mlqueue\n", cmd));
150
151 scsi_set_blocked(cmd, reason);
152
153 /*
154 * Decrement the counters, since these commands are no longer
155 * active on the host/device.
156 */
157 if (unbusy)
158 scsi_device_unbusy(device, cmd);
159
160 /*
161 * Requeue this command. It will go before all other commands
162 * that are already in the queue. Schedule requeue work under
163 * lock such that the kblockd_schedule_work() call happens
164 * before blk_mq_destroy_queue() finishes.
165 */
166 cmd->result = 0;
167
168 blk_mq_requeue_request(scsi_cmd_to_rq(cmd), true);
169}
170
171/**
172 * scsi_queue_insert - Reinsert a command in the queue.
173 * @cmd: command that we are adding to queue.
174 * @reason: why we are inserting command to queue.
175 *
176 * We do this for one of two cases. Either the host is busy and it cannot accept
177 * any more commands for the time being, or the device returned QUEUE_FULL and
178 * can accept no more commands.
179 *
180 * Context: This could be called either from an interrupt context or a normal
181 * process context.
182 */
183void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
184{
185 __scsi_queue_insert(cmd, reason, true);
186}
187
188
189/**
190 * __scsi_execute - insert request and wait for the result
191 * @sdev: scsi device
192 * @cmd: scsi command
193 * @data_direction: data direction
194 * @buffer: data buffer
195 * @bufflen: len of buffer
196 * @sense: optional sense buffer
197 * @sshdr: optional decoded sense header
198 * @timeout: request timeout in HZ
199 * @retries: number of times to retry request
200 * @flags: flags for ->cmd_flags
201 * @rq_flags: flags for ->rq_flags
202 * @resid: optional residual length
203 *
204 * Returns the scsi_cmnd result field if a command was executed, or a negative
205 * Linux error code if we didn't get that far.
206 */
207int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
208 int data_direction, void *buffer, unsigned bufflen,
209 unsigned char *sense, struct scsi_sense_hdr *sshdr,
210 int timeout, int retries, blk_opf_t flags,
211 req_flags_t rq_flags, int *resid)
212{
213 struct request *req;
214 struct scsi_cmnd *scmd;
215 int ret;
216
217 req = scsi_alloc_request(sdev->request_queue,
218 data_direction == DMA_TO_DEVICE ?
219 REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
220 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
221 if (IS_ERR(req))
222 return PTR_ERR(req);
223
224 if (bufflen) {
225 ret = blk_rq_map_kern(sdev->request_queue, req,
226 buffer, bufflen, GFP_NOIO);
227 if (ret)
228 goto out;
229 }
230 scmd = blk_mq_rq_to_pdu(req);
231 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
232 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
233 scmd->allowed = retries;
234 req->timeout = timeout;
235 req->cmd_flags |= flags;
236 req->rq_flags |= rq_flags | RQF_QUIET;
237
238 /*
239 * head injection *required* here otherwise quiesce won't work
240 */
241 blk_execute_rq(req, true);
242
243 /*
244 * Some devices (USB mass-storage in particular) may transfer
245 * garbage data together with a residue indicating that the data
246 * is invalid. Prevent the garbage from being misinterpreted
247 * and prevent security leaks by zeroing out the excess data.
248 */
249 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
250 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
251
252 if (resid)
253 *resid = scmd->resid_len;
254 if (sense && scmd->sense_len)
255 memcpy(sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
256 if (sshdr)
257 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
258 sshdr);
259 ret = scmd->result;
260 out:
261 blk_mq_free_request(req);
262
263 return ret;
264}
265EXPORT_SYMBOL(__scsi_execute);
266
267/*
268 * Wake up the error handler if necessary. Avoid as follows that the error
269 * handler is not woken up if host in-flight requests number ==
270 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
271 * with an RCU read lock in this function to ensure that this function in
272 * its entirety either finishes before scsi_eh_scmd_add() increases the
273 * host_failed counter or that it notices the shost state change made by
274 * scsi_eh_scmd_add().
275 */
276static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
277{
278 unsigned long flags;
279
280 rcu_read_lock();
281 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
282 if (unlikely(scsi_host_in_recovery(shost))) {
283 spin_lock_irqsave(shost->host_lock, flags);
284 if (shost->host_failed || shost->host_eh_scheduled)
285 scsi_eh_wakeup(shost);
286 spin_unlock_irqrestore(shost->host_lock, flags);
287 }
288 rcu_read_unlock();
289}
290
291void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
292{
293 struct Scsi_Host *shost = sdev->host;
294 struct scsi_target *starget = scsi_target(sdev);
295
296 scsi_dec_host_busy(shost, cmd);
297
298 if (starget->can_queue > 0)
299 atomic_dec(&starget->target_busy);
300
301 sbitmap_put(&sdev->budget_map, cmd->budget_token);
302 cmd->budget_token = -1;
303}
304
305static void scsi_kick_queue(struct request_queue *q)
306{
307 blk_mq_run_hw_queues(q, false);
308}
309
310/*
311 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
312 * interrupts disabled.
313 */
314static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
315{
316 struct scsi_device *current_sdev = data;
317
318 if (sdev != current_sdev)
319 blk_mq_run_hw_queues(sdev->request_queue, true);
320}
321
322/*
323 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
324 * and call blk_run_queue for all the scsi_devices on the target -
325 * including current_sdev first.
326 *
327 * Called with *no* scsi locks held.
328 */
329static void scsi_single_lun_run(struct scsi_device *current_sdev)
330{
331 struct Scsi_Host *shost = current_sdev->host;
332 struct scsi_target *starget = scsi_target(current_sdev);
333 unsigned long flags;
334
335 spin_lock_irqsave(shost->host_lock, flags);
336 starget->starget_sdev_user = NULL;
337 spin_unlock_irqrestore(shost->host_lock, flags);
338
339 /*
340 * Call blk_run_queue for all LUNs on the target, starting with
341 * current_sdev. We race with others (to set starget_sdev_user),
342 * but in most cases, we will be first. Ideally, each LU on the
343 * target would get some limited time or requests on the target.
344 */
345 scsi_kick_queue(current_sdev->request_queue);
346
347 spin_lock_irqsave(shost->host_lock, flags);
348 if (!starget->starget_sdev_user)
349 __starget_for_each_device(starget, current_sdev,
350 scsi_kick_sdev_queue);
351 spin_unlock_irqrestore(shost->host_lock, flags);
352}
353
354static inline bool scsi_device_is_busy(struct scsi_device *sdev)
355{
356 if (scsi_device_busy(sdev) >= sdev->queue_depth)
357 return true;
358 if (atomic_read(&sdev->device_blocked) > 0)
359 return true;
360 return false;
361}
362
363static inline bool scsi_target_is_busy(struct scsi_target *starget)
364{
365 if (starget->can_queue > 0) {
366 if (atomic_read(&starget->target_busy) >= starget->can_queue)
367 return true;
368 if (atomic_read(&starget->target_blocked) > 0)
369 return true;
370 }
371 return false;
372}
373
374static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
375{
376 if (atomic_read(&shost->host_blocked) > 0)
377 return true;
378 if (shost->host_self_blocked)
379 return true;
380 return false;
381}
382
383static void scsi_starved_list_run(struct Scsi_Host *shost)
384{
385 LIST_HEAD(starved_list);
386 struct scsi_device *sdev;
387 unsigned long flags;
388
389 spin_lock_irqsave(shost->host_lock, flags);
390 list_splice_init(&shost->starved_list, &starved_list);
391
392 while (!list_empty(&starved_list)) {
393 struct request_queue *slq;
394
395 /*
396 * As long as shost is accepting commands and we have
397 * starved queues, call blk_run_queue. scsi_request_fn
398 * drops the queue_lock and can add us back to the
399 * starved_list.
400 *
401 * host_lock protects the starved_list and starved_entry.
402 * scsi_request_fn must get the host_lock before checking
403 * or modifying starved_list or starved_entry.
404 */
405 if (scsi_host_is_busy(shost))
406 break;
407
408 sdev = list_entry(starved_list.next,
409 struct scsi_device, starved_entry);
410 list_del_init(&sdev->starved_entry);
411 if (scsi_target_is_busy(scsi_target(sdev))) {
412 list_move_tail(&sdev->starved_entry,
413 &shost->starved_list);
414 continue;
415 }
416
417 /*
418 * Once we drop the host lock, a racing scsi_remove_device()
419 * call may remove the sdev from the starved list and destroy
420 * it and the queue. Mitigate by taking a reference to the
421 * queue and never touching the sdev again after we drop the
422 * host lock. Note: if __scsi_remove_device() invokes
423 * blk_mq_destroy_queue() before the queue is run from this
424 * function then blk_run_queue() will return immediately since
425 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
426 */
427 slq = sdev->request_queue;
428 if (!blk_get_queue(slq))
429 continue;
430 spin_unlock_irqrestore(shost->host_lock, flags);
431
432 scsi_kick_queue(slq);
433 blk_put_queue(slq);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 }
437 /* put any unprocessed entries back */
438 list_splice(&starved_list, &shost->starved_list);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440}
441
442/**
443 * scsi_run_queue - Select a proper request queue to serve next.
444 * @q: last request's queue
445 *
446 * The previous command was completely finished, start a new one if possible.
447 */
448static void scsi_run_queue(struct request_queue *q)
449{
450 struct scsi_device *sdev = q->queuedata;
451
452 if (scsi_target(sdev)->single_lun)
453 scsi_single_lun_run(sdev);
454 if (!list_empty(&sdev->host->starved_list))
455 scsi_starved_list_run(sdev->host);
456
457 blk_mq_run_hw_queues(q, false);
458}
459
460void scsi_requeue_run_queue(struct work_struct *work)
461{
462 struct scsi_device *sdev;
463 struct request_queue *q;
464
465 sdev = container_of(work, struct scsi_device, requeue_work);
466 q = sdev->request_queue;
467 scsi_run_queue(q);
468}
469
470void scsi_run_host_queues(struct Scsi_Host *shost)
471{
472 struct scsi_device *sdev;
473
474 shost_for_each_device(sdev, shost)
475 scsi_run_queue(sdev->request_queue);
476}
477
478static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
479{
480 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
481 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
482
483 if (drv->uninit_command)
484 drv->uninit_command(cmd);
485 }
486}
487
488void scsi_free_sgtables(struct scsi_cmnd *cmd)
489{
490 if (cmd->sdb.table.nents)
491 sg_free_table_chained(&cmd->sdb.table,
492 SCSI_INLINE_SG_CNT);
493 if (scsi_prot_sg_count(cmd))
494 sg_free_table_chained(&cmd->prot_sdb->table,
495 SCSI_INLINE_PROT_SG_CNT);
496}
497EXPORT_SYMBOL_GPL(scsi_free_sgtables);
498
499static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
500{
501 scsi_free_sgtables(cmd);
502 scsi_uninit_cmd(cmd);
503}
504
505static void scsi_run_queue_async(struct scsi_device *sdev)
506{
507 if (scsi_target(sdev)->single_lun ||
508 !list_empty(&sdev->host->starved_list)) {
509 kblockd_schedule_work(&sdev->requeue_work);
510 } else {
511 /*
512 * smp_mb() present in sbitmap_queue_clear() or implied in
513 * .end_io is for ordering writing .device_busy in
514 * scsi_device_unbusy() and reading sdev->restarts.
515 */
516 int old = atomic_read(&sdev->restarts);
517
518 /*
519 * ->restarts has to be kept as non-zero if new budget
520 * contention occurs.
521 *
522 * No need to run queue when either another re-run
523 * queue wins in updating ->restarts or a new budget
524 * contention occurs.
525 */
526 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
527 blk_mq_run_hw_queues(sdev->request_queue, true);
528 }
529}
530
531/* Returns false when no more bytes to process, true if there are more */
532static bool scsi_end_request(struct request *req, blk_status_t error,
533 unsigned int bytes)
534{
535 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
536 struct scsi_device *sdev = cmd->device;
537 struct request_queue *q = sdev->request_queue;
538
539 if (blk_update_request(req, error, bytes))
540 return true;
541
542 // XXX:
543 if (blk_queue_add_random(q))
544 add_disk_randomness(req->q->disk);
545
546 if (!blk_rq_is_passthrough(req)) {
547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
548 cmd->flags &= ~SCMD_INITIALIZED;
549 }
550
551 /*
552 * Calling rcu_barrier() is not necessary here because the
553 * SCSI error handler guarantees that the function called by
554 * call_rcu() has been called before scsi_end_request() is
555 * called.
556 */
557 destroy_rcu_head(&cmd->rcu);
558
559 /*
560 * In the MQ case the command gets freed by __blk_mq_end_request,
561 * so we have to do all cleanup that depends on it earlier.
562 *
563 * We also can't kick the queues from irq context, so we
564 * will have to defer it to a workqueue.
565 */
566 scsi_mq_uninit_cmd(cmd);
567
568 /*
569 * queue is still alive, so grab the ref for preventing it
570 * from being cleaned up during running queue.
571 */
572 percpu_ref_get(&q->q_usage_counter);
573
574 __blk_mq_end_request(req, error);
575
576 scsi_run_queue_async(sdev);
577
578 percpu_ref_put(&q->q_usage_counter);
579 return false;
580}
581
582static inline u8 get_scsi_ml_byte(int result)
583{
584 return (result >> 8) & 0xff;
585}
586
587/**
588 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
589 * @result: scsi error code
590 *
591 * Translate a SCSI result code into a blk_status_t value.
592 */
593static blk_status_t scsi_result_to_blk_status(int result)
594{
595 /*
596 * Check the scsi-ml byte first in case we converted a host or status
597 * byte.
598 */
599 switch (get_scsi_ml_byte(result)) {
600 case SCSIML_STAT_OK:
601 break;
602 case SCSIML_STAT_RESV_CONFLICT:
603 return BLK_STS_NEXUS;
604 case SCSIML_STAT_NOSPC:
605 return BLK_STS_NOSPC;
606 case SCSIML_STAT_MED_ERROR:
607 return BLK_STS_MEDIUM;
608 case SCSIML_STAT_TGT_FAILURE:
609 return BLK_STS_TARGET;
610 }
611
612 switch (host_byte(result)) {
613 case DID_OK:
614 if (scsi_status_is_good(result))
615 return BLK_STS_OK;
616 return BLK_STS_IOERR;
617 case DID_TRANSPORT_FAILFAST:
618 case DID_TRANSPORT_MARGINAL:
619 return BLK_STS_TRANSPORT;
620 default:
621 return BLK_STS_IOERR;
622 }
623}
624
625/**
626 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
627 * @rq: request to examine
628 *
629 * Description:
630 * A request could be merge of IOs which require different failure
631 * handling. This function determines the number of bytes which
632 * can be failed from the beginning of the request without
633 * crossing into area which need to be retried further.
634 *
635 * Return:
636 * The number of bytes to fail.
637 */
638static unsigned int scsi_rq_err_bytes(const struct request *rq)
639{
640 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
641 unsigned int bytes = 0;
642 struct bio *bio;
643
644 if (!(rq->rq_flags & RQF_MIXED_MERGE))
645 return blk_rq_bytes(rq);
646
647 /*
648 * Currently the only 'mixing' which can happen is between
649 * different fastfail types. We can safely fail portions
650 * which have all the failfast bits that the first one has -
651 * the ones which are at least as eager to fail as the first
652 * one.
653 */
654 for (bio = rq->bio; bio; bio = bio->bi_next) {
655 if ((bio->bi_opf & ff) != ff)
656 break;
657 bytes += bio->bi_iter.bi_size;
658 }
659
660 /* this could lead to infinite loop */
661 BUG_ON(blk_rq_bytes(rq) && !bytes);
662 return bytes;
663}
664
665static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
666{
667 struct request *req = scsi_cmd_to_rq(cmd);
668 unsigned long wait_for;
669
670 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
671 return false;
672
673 wait_for = (cmd->allowed + 1) * req->timeout;
674 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
675 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
676 wait_for/HZ);
677 return true;
678 }
679 return false;
680}
681
682/*
683 * When ALUA transition state is returned, reprep the cmd to
684 * use the ALUA handler's transition timeout. Delay the reprep
685 * 1 sec to avoid aggressive retries of the target in that
686 * state.
687 */
688#define ALUA_TRANSITION_REPREP_DELAY 1000
689
690/* Helper for scsi_io_completion() when special action required. */
691static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
692{
693 struct request *req = scsi_cmd_to_rq(cmd);
694 int level = 0;
695 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
696 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
697 struct scsi_sense_hdr sshdr;
698 bool sense_valid;
699 bool sense_current = true; /* false implies "deferred sense" */
700 blk_status_t blk_stat;
701
702 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
703 if (sense_valid)
704 sense_current = !scsi_sense_is_deferred(&sshdr);
705
706 blk_stat = scsi_result_to_blk_status(result);
707
708 if (host_byte(result) == DID_RESET) {
709 /* Third party bus reset or reset for error recovery
710 * reasons. Just retry the command and see what
711 * happens.
712 */
713 action = ACTION_RETRY;
714 } else if (sense_valid && sense_current) {
715 switch (sshdr.sense_key) {
716 case UNIT_ATTENTION:
717 if (cmd->device->removable) {
718 /* Detected disc change. Set a bit
719 * and quietly refuse further access.
720 */
721 cmd->device->changed = 1;
722 action = ACTION_FAIL;
723 } else {
724 /* Must have been a power glitch, or a
725 * bus reset. Could not have been a
726 * media change, so we just retry the
727 * command and see what happens.
728 */
729 action = ACTION_RETRY;
730 }
731 break;
732 case ILLEGAL_REQUEST:
733 /* If we had an ILLEGAL REQUEST returned, then
734 * we may have performed an unsupported
735 * command. The only thing this should be
736 * would be a ten byte read where only a six
737 * byte read was supported. Also, on a system
738 * where READ CAPACITY failed, we may have
739 * read past the end of the disk.
740 */
741 if ((cmd->device->use_10_for_rw &&
742 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
743 (cmd->cmnd[0] == READ_10 ||
744 cmd->cmnd[0] == WRITE_10)) {
745 /* This will issue a new 6-byte command. */
746 cmd->device->use_10_for_rw = 0;
747 action = ACTION_REPREP;
748 } else if (sshdr.asc == 0x10) /* DIX */ {
749 action = ACTION_FAIL;
750 blk_stat = BLK_STS_PROTECTION;
751 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
752 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
753 action = ACTION_FAIL;
754 blk_stat = BLK_STS_TARGET;
755 } else
756 action = ACTION_FAIL;
757 break;
758 case ABORTED_COMMAND:
759 action = ACTION_FAIL;
760 if (sshdr.asc == 0x10) /* DIF */
761 blk_stat = BLK_STS_PROTECTION;
762 break;
763 case NOT_READY:
764 /* If the device is in the process of becoming
765 * ready, or has a temporary blockage, retry.
766 */
767 if (sshdr.asc == 0x04) {
768 switch (sshdr.ascq) {
769 case 0x01: /* becoming ready */
770 case 0x04: /* format in progress */
771 case 0x05: /* rebuild in progress */
772 case 0x06: /* recalculation in progress */
773 case 0x07: /* operation in progress */
774 case 0x08: /* Long write in progress */
775 case 0x09: /* self test in progress */
776 case 0x11: /* notify (enable spinup) required */
777 case 0x14: /* space allocation in progress */
778 case 0x1a: /* start stop unit in progress */
779 case 0x1b: /* sanitize in progress */
780 case 0x1d: /* configuration in progress */
781 case 0x24: /* depopulation in progress */
782 action = ACTION_DELAYED_RETRY;
783 break;
784 case 0x0a: /* ALUA state transition */
785 action = ACTION_DELAYED_REPREP;
786 break;
787 default:
788 action = ACTION_FAIL;
789 break;
790 }
791 } else
792 action = ACTION_FAIL;
793 break;
794 case VOLUME_OVERFLOW:
795 /* See SSC3rXX or current. */
796 action = ACTION_FAIL;
797 break;
798 case DATA_PROTECT:
799 action = ACTION_FAIL;
800 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
801 (sshdr.asc == 0x55 &&
802 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
803 /* Insufficient zone resources */
804 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
805 }
806 break;
807 default:
808 action = ACTION_FAIL;
809 break;
810 }
811 } else
812 action = ACTION_FAIL;
813
814 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
815 action = ACTION_FAIL;
816
817 switch (action) {
818 case ACTION_FAIL:
819 /* Give up and fail the remainder of the request */
820 if (!(req->rq_flags & RQF_QUIET)) {
821 static DEFINE_RATELIMIT_STATE(_rs,
822 DEFAULT_RATELIMIT_INTERVAL,
823 DEFAULT_RATELIMIT_BURST);
824
825 if (unlikely(scsi_logging_level))
826 level =
827 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
828 SCSI_LOG_MLCOMPLETE_BITS);
829
830 /*
831 * if logging is enabled the failure will be printed
832 * in scsi_log_completion(), so avoid duplicate messages
833 */
834 if (!level && __ratelimit(&_rs)) {
835 scsi_print_result(cmd, NULL, FAILED);
836 if (sense_valid)
837 scsi_print_sense(cmd);
838 scsi_print_command(cmd);
839 }
840 }
841 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
842 return;
843 fallthrough;
844 case ACTION_REPREP:
845 scsi_mq_requeue_cmd(cmd, 0);
846 break;
847 case ACTION_DELAYED_REPREP:
848 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
849 break;
850 case ACTION_RETRY:
851 /* Retry the same command immediately */
852 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
853 break;
854 case ACTION_DELAYED_RETRY:
855 /* Retry the same command after a delay */
856 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
857 break;
858 }
859}
860
861/*
862 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
863 * new result that may suppress further error checking. Also modifies
864 * *blk_statp in some cases.
865 */
866static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
867 blk_status_t *blk_statp)
868{
869 bool sense_valid;
870 bool sense_current = true; /* false implies "deferred sense" */
871 struct request *req = scsi_cmd_to_rq(cmd);
872 struct scsi_sense_hdr sshdr;
873
874 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
875 if (sense_valid)
876 sense_current = !scsi_sense_is_deferred(&sshdr);
877
878 if (blk_rq_is_passthrough(req)) {
879 if (sense_valid) {
880 /*
881 * SG_IO wants current and deferred errors
882 */
883 cmd->sense_len = min(8 + cmd->sense_buffer[7],
884 SCSI_SENSE_BUFFERSIZE);
885 }
886 if (sense_current)
887 *blk_statp = scsi_result_to_blk_status(result);
888 } else if (blk_rq_bytes(req) == 0 && sense_current) {
889 /*
890 * Flush commands do not transfers any data, and thus cannot use
891 * good_bytes != blk_rq_bytes(req) as the signal for an error.
892 * This sets *blk_statp explicitly for the problem case.
893 */
894 *blk_statp = scsi_result_to_blk_status(result);
895 }
896 /*
897 * Recovered errors need reporting, but they're always treated as
898 * success, so fiddle the result code here. For passthrough requests
899 * we already took a copy of the original into sreq->result which
900 * is what gets returned to the user
901 */
902 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
903 bool do_print = true;
904 /*
905 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
906 * skip print since caller wants ATA registers. Only occurs
907 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
908 */
909 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
910 do_print = false;
911 else if (req->rq_flags & RQF_QUIET)
912 do_print = false;
913 if (do_print)
914 scsi_print_sense(cmd);
915 result = 0;
916 /* for passthrough, *blk_statp may be set */
917 *blk_statp = BLK_STS_OK;
918 }
919 /*
920 * Another corner case: the SCSI status byte is non-zero but 'good'.
921 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
922 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
923 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
924 * intermediate statuses (both obsolete in SAM-4) as good.
925 */
926 if ((result & 0xff) && scsi_status_is_good(result)) {
927 result = 0;
928 *blk_statp = BLK_STS_OK;
929 }
930 return result;
931}
932
933/**
934 * scsi_io_completion - Completion processing for SCSI commands.
935 * @cmd: command that is finished.
936 * @good_bytes: number of processed bytes.
937 *
938 * We will finish off the specified number of sectors. If we are done, the
939 * command block will be released and the queue function will be goosed. If we
940 * are not done then we have to figure out what to do next:
941 *
942 * a) We can call scsi_mq_requeue_cmd(). The request will be
943 * unprepared and put back on the queue. Then a new command will
944 * be created for it. This should be used if we made forward
945 * progress, or if we want to switch from READ(10) to READ(6) for
946 * example.
947 *
948 * b) We can call scsi_io_completion_action(). The request will be
949 * put back on the queue and retried using the same command as
950 * before, possibly after a delay.
951 *
952 * c) We can call scsi_end_request() with blk_stat other than
953 * BLK_STS_OK, to fail the remainder of the request.
954 */
955void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
956{
957 int result = cmd->result;
958 struct request *req = scsi_cmd_to_rq(cmd);
959 blk_status_t blk_stat = BLK_STS_OK;
960
961 if (unlikely(result)) /* a nz result may or may not be an error */
962 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
963
964 /*
965 * Next deal with any sectors which we were able to correctly
966 * handle.
967 */
968 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
969 "%u sectors total, %d bytes done.\n",
970 blk_rq_sectors(req), good_bytes));
971
972 /*
973 * Failed, zero length commands always need to drop down
974 * to retry code. Fast path should return in this block.
975 */
976 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
977 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
978 return; /* no bytes remaining */
979 }
980
981 /* Kill remainder if no retries. */
982 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
983 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
984 WARN_ONCE(true,
985 "Bytes remaining after failed, no-retry command");
986 return;
987 }
988
989 /*
990 * If there had been no error, but we have leftover bytes in the
991 * request just queue the command up again.
992 */
993 if (likely(result == 0))
994 scsi_mq_requeue_cmd(cmd, 0);
995 else
996 scsi_io_completion_action(cmd, result);
997}
998
999static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1000 struct request *rq)
1001{
1002 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1003 !op_is_write(req_op(rq)) &&
1004 sdev->host->hostt->dma_need_drain(rq);
1005}
1006
1007/**
1008 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1009 * @cmd: SCSI command data structure to initialize.
1010 *
1011 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1012 * for @cmd.
1013 *
1014 * Returns:
1015 * * BLK_STS_OK - on success
1016 * * BLK_STS_RESOURCE - if the failure is retryable
1017 * * BLK_STS_IOERR - if the failure is fatal
1018 */
1019blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1020{
1021 struct scsi_device *sdev = cmd->device;
1022 struct request *rq = scsi_cmd_to_rq(cmd);
1023 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1024 struct scatterlist *last_sg = NULL;
1025 blk_status_t ret;
1026 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1027 int count;
1028
1029 if (WARN_ON_ONCE(!nr_segs))
1030 return BLK_STS_IOERR;
1031
1032 /*
1033 * Make sure there is space for the drain. The driver must adjust
1034 * max_hw_segments to be prepared for this.
1035 */
1036 if (need_drain)
1037 nr_segs++;
1038
1039 /*
1040 * If sg table allocation fails, requeue request later.
1041 */
1042 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1043 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1044 return BLK_STS_RESOURCE;
1045
1046 /*
1047 * Next, walk the list, and fill in the addresses and sizes of
1048 * each segment.
1049 */
1050 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1051
1052 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1053 unsigned int pad_len =
1054 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1055
1056 last_sg->length += pad_len;
1057 cmd->extra_len += pad_len;
1058 }
1059
1060 if (need_drain) {
1061 sg_unmark_end(last_sg);
1062 last_sg = sg_next(last_sg);
1063 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1064 sg_mark_end(last_sg);
1065
1066 cmd->extra_len += sdev->dma_drain_len;
1067 count++;
1068 }
1069
1070 BUG_ON(count > cmd->sdb.table.nents);
1071 cmd->sdb.table.nents = count;
1072 cmd->sdb.length = blk_rq_payload_bytes(rq);
1073
1074 if (blk_integrity_rq(rq)) {
1075 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1076 int ivecs;
1077
1078 if (WARN_ON_ONCE(!prot_sdb)) {
1079 /*
1080 * This can happen if someone (e.g. multipath)
1081 * queues a command to a device on an adapter
1082 * that does not support DIX.
1083 */
1084 ret = BLK_STS_IOERR;
1085 goto out_free_sgtables;
1086 }
1087
1088 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1089
1090 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1091 prot_sdb->table.sgl,
1092 SCSI_INLINE_PROT_SG_CNT)) {
1093 ret = BLK_STS_RESOURCE;
1094 goto out_free_sgtables;
1095 }
1096
1097 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1098 prot_sdb->table.sgl);
1099 BUG_ON(count > ivecs);
1100 BUG_ON(count > queue_max_integrity_segments(rq->q));
1101
1102 cmd->prot_sdb = prot_sdb;
1103 cmd->prot_sdb->table.nents = count;
1104 }
1105
1106 return BLK_STS_OK;
1107out_free_sgtables:
1108 scsi_free_sgtables(cmd);
1109 return ret;
1110}
1111EXPORT_SYMBOL(scsi_alloc_sgtables);
1112
1113/**
1114 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1115 * @rq: Request associated with the SCSI command to be initialized.
1116 *
1117 * This function initializes the members of struct scsi_cmnd that must be
1118 * initialized before request processing starts and that won't be
1119 * reinitialized if a SCSI command is requeued.
1120 */
1121static void scsi_initialize_rq(struct request *rq)
1122{
1123 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1124
1125 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1126 cmd->cmd_len = MAX_COMMAND_SIZE;
1127 cmd->sense_len = 0;
1128 init_rcu_head(&cmd->rcu);
1129 cmd->jiffies_at_alloc = jiffies;
1130 cmd->retries = 0;
1131}
1132
1133struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1134 blk_mq_req_flags_t flags)
1135{
1136 struct request *rq;
1137
1138 rq = blk_mq_alloc_request(q, opf, flags);
1139 if (!IS_ERR(rq))
1140 scsi_initialize_rq(rq);
1141 return rq;
1142}
1143EXPORT_SYMBOL_GPL(scsi_alloc_request);
1144
1145/*
1146 * Only called when the request isn't completed by SCSI, and not freed by
1147 * SCSI
1148 */
1149static void scsi_cleanup_rq(struct request *rq)
1150{
1151 if (rq->rq_flags & RQF_DONTPREP) {
1152 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1153 rq->rq_flags &= ~RQF_DONTPREP;
1154 }
1155}
1156
1157/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1158void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1159{
1160 struct request *rq = scsi_cmd_to_rq(cmd);
1161
1162 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1163 cmd->flags |= SCMD_INITIALIZED;
1164 scsi_initialize_rq(rq);
1165 }
1166
1167 cmd->device = dev;
1168 INIT_LIST_HEAD(&cmd->eh_entry);
1169 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1170}
1171
1172static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1173 struct request *req)
1174{
1175 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1176
1177 /*
1178 * Passthrough requests may transfer data, in which case they must
1179 * a bio attached to them. Or they might contain a SCSI command
1180 * that does not transfer data, in which case they may optionally
1181 * submit a request without an attached bio.
1182 */
1183 if (req->bio) {
1184 blk_status_t ret = scsi_alloc_sgtables(cmd);
1185 if (unlikely(ret != BLK_STS_OK))
1186 return ret;
1187 } else {
1188 BUG_ON(blk_rq_bytes(req));
1189
1190 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1191 }
1192
1193 cmd->transfersize = blk_rq_bytes(req);
1194 return BLK_STS_OK;
1195}
1196
1197static blk_status_t
1198scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1199{
1200 switch (sdev->sdev_state) {
1201 case SDEV_CREATED:
1202 return BLK_STS_OK;
1203 case SDEV_OFFLINE:
1204 case SDEV_TRANSPORT_OFFLINE:
1205 /*
1206 * If the device is offline we refuse to process any
1207 * commands. The device must be brought online
1208 * before trying any recovery commands.
1209 */
1210 if (!sdev->offline_already) {
1211 sdev->offline_already = true;
1212 sdev_printk(KERN_ERR, sdev,
1213 "rejecting I/O to offline device\n");
1214 }
1215 return BLK_STS_IOERR;
1216 case SDEV_DEL:
1217 /*
1218 * If the device is fully deleted, we refuse to
1219 * process any commands as well.
1220 */
1221 sdev_printk(KERN_ERR, sdev,
1222 "rejecting I/O to dead device\n");
1223 return BLK_STS_IOERR;
1224 case SDEV_BLOCK:
1225 case SDEV_CREATED_BLOCK:
1226 return BLK_STS_RESOURCE;
1227 case SDEV_QUIESCE:
1228 /*
1229 * If the device is blocked we only accept power management
1230 * commands.
1231 */
1232 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1233 return BLK_STS_RESOURCE;
1234 return BLK_STS_OK;
1235 default:
1236 /*
1237 * For any other not fully online state we only allow
1238 * power management commands.
1239 */
1240 if (req && !(req->rq_flags & RQF_PM))
1241 return BLK_STS_OFFLINE;
1242 return BLK_STS_OK;
1243 }
1244}
1245
1246/*
1247 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1248 * and return the token else return -1.
1249 */
1250static inline int scsi_dev_queue_ready(struct request_queue *q,
1251 struct scsi_device *sdev)
1252{
1253 int token;
1254
1255 token = sbitmap_get(&sdev->budget_map);
1256 if (atomic_read(&sdev->device_blocked)) {
1257 if (token < 0)
1258 goto out;
1259
1260 if (scsi_device_busy(sdev) > 1)
1261 goto out_dec;
1262
1263 /*
1264 * unblock after device_blocked iterates to zero
1265 */
1266 if (atomic_dec_return(&sdev->device_blocked) > 0)
1267 goto out_dec;
1268 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1269 "unblocking device at zero depth\n"));
1270 }
1271
1272 return token;
1273out_dec:
1274 if (token >= 0)
1275 sbitmap_put(&sdev->budget_map, token);
1276out:
1277 return -1;
1278}
1279
1280/*
1281 * scsi_target_queue_ready: checks if there we can send commands to target
1282 * @sdev: scsi device on starget to check.
1283 */
1284static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1285 struct scsi_device *sdev)
1286{
1287 struct scsi_target *starget = scsi_target(sdev);
1288 unsigned int busy;
1289
1290 if (starget->single_lun) {
1291 spin_lock_irq(shost->host_lock);
1292 if (starget->starget_sdev_user &&
1293 starget->starget_sdev_user != sdev) {
1294 spin_unlock_irq(shost->host_lock);
1295 return 0;
1296 }
1297 starget->starget_sdev_user = sdev;
1298 spin_unlock_irq(shost->host_lock);
1299 }
1300
1301 if (starget->can_queue <= 0)
1302 return 1;
1303
1304 busy = atomic_inc_return(&starget->target_busy) - 1;
1305 if (atomic_read(&starget->target_blocked) > 0) {
1306 if (busy)
1307 goto starved;
1308
1309 /*
1310 * unblock after target_blocked iterates to zero
1311 */
1312 if (atomic_dec_return(&starget->target_blocked) > 0)
1313 goto out_dec;
1314
1315 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1316 "unblocking target at zero depth\n"));
1317 }
1318
1319 if (busy >= starget->can_queue)
1320 goto starved;
1321
1322 return 1;
1323
1324starved:
1325 spin_lock_irq(shost->host_lock);
1326 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1327 spin_unlock_irq(shost->host_lock);
1328out_dec:
1329 if (starget->can_queue > 0)
1330 atomic_dec(&starget->target_busy);
1331 return 0;
1332}
1333
1334/*
1335 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1336 * return 0. We must end up running the queue again whenever 0 is
1337 * returned, else IO can hang.
1338 */
1339static inline int scsi_host_queue_ready(struct request_queue *q,
1340 struct Scsi_Host *shost,
1341 struct scsi_device *sdev,
1342 struct scsi_cmnd *cmd)
1343{
1344 if (atomic_read(&shost->host_blocked) > 0) {
1345 if (scsi_host_busy(shost) > 0)
1346 goto starved;
1347
1348 /*
1349 * unblock after host_blocked iterates to zero
1350 */
1351 if (atomic_dec_return(&shost->host_blocked) > 0)
1352 goto out_dec;
1353
1354 SCSI_LOG_MLQUEUE(3,
1355 shost_printk(KERN_INFO, shost,
1356 "unblocking host at zero depth\n"));
1357 }
1358
1359 if (shost->host_self_blocked)
1360 goto starved;
1361
1362 /* We're OK to process the command, so we can't be starved */
1363 if (!list_empty(&sdev->starved_entry)) {
1364 spin_lock_irq(shost->host_lock);
1365 if (!list_empty(&sdev->starved_entry))
1366 list_del_init(&sdev->starved_entry);
1367 spin_unlock_irq(shost->host_lock);
1368 }
1369
1370 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1371
1372 return 1;
1373
1374starved:
1375 spin_lock_irq(shost->host_lock);
1376 if (list_empty(&sdev->starved_entry))
1377 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1378 spin_unlock_irq(shost->host_lock);
1379out_dec:
1380 scsi_dec_host_busy(shost, cmd);
1381 return 0;
1382}
1383
1384/*
1385 * Busy state exporting function for request stacking drivers.
1386 *
1387 * For efficiency, no lock is taken to check the busy state of
1388 * shost/starget/sdev, since the returned value is not guaranteed and
1389 * may be changed after request stacking drivers call the function,
1390 * regardless of taking lock or not.
1391 *
1392 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1393 * needs to return 'not busy'. Otherwise, request stacking drivers
1394 * may hold requests forever.
1395 */
1396static bool scsi_mq_lld_busy(struct request_queue *q)
1397{
1398 struct scsi_device *sdev = q->queuedata;
1399 struct Scsi_Host *shost;
1400
1401 if (blk_queue_dying(q))
1402 return false;
1403
1404 shost = sdev->host;
1405
1406 /*
1407 * Ignore host/starget busy state.
1408 * Since block layer does not have a concept of fairness across
1409 * multiple queues, congestion of host/starget needs to be handled
1410 * in SCSI layer.
1411 */
1412 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1413 return true;
1414
1415 return false;
1416}
1417
1418/*
1419 * Block layer request completion callback. May be called from interrupt
1420 * context.
1421 */
1422static void scsi_complete(struct request *rq)
1423{
1424 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1425 enum scsi_disposition disposition;
1426
1427 INIT_LIST_HEAD(&cmd->eh_entry);
1428
1429 atomic_inc(&cmd->device->iodone_cnt);
1430 if (cmd->result)
1431 atomic_inc(&cmd->device->ioerr_cnt);
1432
1433 disposition = scsi_decide_disposition(cmd);
1434 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1435 disposition = SUCCESS;
1436
1437 scsi_log_completion(cmd, disposition);
1438
1439 switch (disposition) {
1440 case SUCCESS:
1441 scsi_finish_command(cmd);
1442 break;
1443 case NEEDS_RETRY:
1444 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1445 break;
1446 case ADD_TO_MLQUEUE:
1447 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1448 break;
1449 default:
1450 scsi_eh_scmd_add(cmd);
1451 break;
1452 }
1453}
1454
1455/**
1456 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1457 * @cmd: command block we are dispatching.
1458 *
1459 * Return: nonzero return request was rejected and device's queue needs to be
1460 * plugged.
1461 */
1462static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1463{
1464 struct Scsi_Host *host = cmd->device->host;
1465 int rtn = 0;
1466
1467 /* check if the device is still usable */
1468 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1469 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1470 * returns an immediate error upwards, and signals
1471 * that the device is no longer present */
1472 cmd->result = DID_NO_CONNECT << 16;
1473 goto done;
1474 }
1475
1476 /* Check to see if the scsi lld made this device blocked. */
1477 if (unlikely(scsi_device_blocked(cmd->device))) {
1478 /*
1479 * in blocked state, the command is just put back on
1480 * the device queue. The suspend state has already
1481 * blocked the queue so future requests should not
1482 * occur until the device transitions out of the
1483 * suspend state.
1484 */
1485 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1486 "queuecommand : device blocked\n"));
1487 return SCSI_MLQUEUE_DEVICE_BUSY;
1488 }
1489
1490 /* Store the LUN value in cmnd, if needed. */
1491 if (cmd->device->lun_in_cdb)
1492 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1493 (cmd->device->lun << 5 & 0xe0);
1494
1495 scsi_log_send(cmd);
1496
1497 /*
1498 * Before we queue this command, check if the command
1499 * length exceeds what the host adapter can handle.
1500 */
1501 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1502 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1503 "queuecommand : command too long. "
1504 "cdb_size=%d host->max_cmd_len=%d\n",
1505 cmd->cmd_len, cmd->device->host->max_cmd_len));
1506 cmd->result = (DID_ABORT << 16);
1507 goto done;
1508 }
1509
1510 if (unlikely(host->shost_state == SHOST_DEL)) {
1511 cmd->result = (DID_NO_CONNECT << 16);
1512 goto done;
1513
1514 }
1515
1516 trace_scsi_dispatch_cmd_start(cmd);
1517 rtn = host->hostt->queuecommand(host, cmd);
1518 if (rtn) {
1519 trace_scsi_dispatch_cmd_error(cmd, rtn);
1520 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1521 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1522 rtn = SCSI_MLQUEUE_HOST_BUSY;
1523
1524 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1525 "queuecommand : request rejected\n"));
1526 }
1527
1528 return rtn;
1529 done:
1530 scsi_done(cmd);
1531 return 0;
1532}
1533
1534/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1535static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1536{
1537 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1538 sizeof(struct scatterlist);
1539}
1540
1541static blk_status_t scsi_prepare_cmd(struct request *req)
1542{
1543 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1544 struct scsi_device *sdev = req->q->queuedata;
1545 struct Scsi_Host *shost = sdev->host;
1546 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1547 struct scatterlist *sg;
1548
1549 scsi_init_command(sdev, cmd);
1550
1551 cmd->eh_eflags = 0;
1552 cmd->prot_type = 0;
1553 cmd->prot_flags = 0;
1554 cmd->submitter = 0;
1555 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1556 cmd->underflow = 0;
1557 cmd->transfersize = 0;
1558 cmd->host_scribble = NULL;
1559 cmd->result = 0;
1560 cmd->extra_len = 0;
1561 cmd->state = 0;
1562 if (in_flight)
1563 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1564
1565 /*
1566 * Only clear the driver-private command data if the LLD does not supply
1567 * a function to initialize that data.
1568 */
1569 if (!shost->hostt->init_cmd_priv)
1570 memset(cmd + 1, 0, shost->hostt->cmd_size);
1571
1572 cmd->prot_op = SCSI_PROT_NORMAL;
1573 if (blk_rq_bytes(req))
1574 cmd->sc_data_direction = rq_dma_dir(req);
1575 else
1576 cmd->sc_data_direction = DMA_NONE;
1577
1578 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1579 cmd->sdb.table.sgl = sg;
1580
1581 if (scsi_host_get_prot(shost)) {
1582 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1583
1584 cmd->prot_sdb->table.sgl =
1585 (struct scatterlist *)(cmd->prot_sdb + 1);
1586 }
1587
1588 /*
1589 * Special handling for passthrough commands, which don't go to the ULP
1590 * at all:
1591 */
1592 if (blk_rq_is_passthrough(req))
1593 return scsi_setup_scsi_cmnd(sdev, req);
1594
1595 if (sdev->handler && sdev->handler->prep_fn) {
1596 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1597
1598 if (ret != BLK_STS_OK)
1599 return ret;
1600 }
1601
1602 /* Usually overridden by the ULP */
1603 cmd->allowed = 0;
1604 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1605 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1606}
1607
1608static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1609{
1610 struct request *req = scsi_cmd_to_rq(cmd);
1611
1612 switch (cmd->submitter) {
1613 case SUBMITTED_BY_BLOCK_LAYER:
1614 break;
1615 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1616 return scsi_eh_done(cmd);
1617 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1618 return;
1619 }
1620
1621 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1622 return;
1623 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1624 return;
1625 trace_scsi_dispatch_cmd_done(cmd);
1626
1627 if (complete_directly)
1628 blk_mq_complete_request_direct(req, scsi_complete);
1629 else
1630 blk_mq_complete_request(req);
1631}
1632
1633void scsi_done(struct scsi_cmnd *cmd)
1634{
1635 scsi_done_internal(cmd, false);
1636}
1637EXPORT_SYMBOL(scsi_done);
1638
1639void scsi_done_direct(struct scsi_cmnd *cmd)
1640{
1641 scsi_done_internal(cmd, true);
1642}
1643EXPORT_SYMBOL(scsi_done_direct);
1644
1645static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1646{
1647 struct scsi_device *sdev = q->queuedata;
1648
1649 sbitmap_put(&sdev->budget_map, budget_token);
1650}
1651
1652/*
1653 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1654 * not change behaviour from the previous unplug mechanism, experimentation
1655 * may prove this needs changing.
1656 */
1657#define SCSI_QUEUE_DELAY 3
1658
1659static int scsi_mq_get_budget(struct request_queue *q)
1660{
1661 struct scsi_device *sdev = q->queuedata;
1662 int token = scsi_dev_queue_ready(q, sdev);
1663
1664 if (token >= 0)
1665 return token;
1666
1667 atomic_inc(&sdev->restarts);
1668
1669 /*
1670 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1671 * .restarts must be incremented before .device_busy is read because the
1672 * code in scsi_run_queue_async() depends on the order of these operations.
1673 */
1674 smp_mb__after_atomic();
1675
1676 /*
1677 * If all in-flight requests originated from this LUN are completed
1678 * before reading .device_busy, sdev->device_busy will be observed as
1679 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1680 * soon. Otherwise, completion of one of these requests will observe
1681 * the .restarts flag, and the request queue will be run for handling
1682 * this request, see scsi_end_request().
1683 */
1684 if (unlikely(scsi_device_busy(sdev) == 0 &&
1685 !scsi_device_blocked(sdev)))
1686 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1687 return -1;
1688}
1689
1690static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1691{
1692 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1693
1694 cmd->budget_token = token;
1695}
1696
1697static int scsi_mq_get_rq_budget_token(struct request *req)
1698{
1699 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1700
1701 return cmd->budget_token;
1702}
1703
1704static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1705 const struct blk_mq_queue_data *bd)
1706{
1707 struct request *req = bd->rq;
1708 struct request_queue *q = req->q;
1709 struct scsi_device *sdev = q->queuedata;
1710 struct Scsi_Host *shost = sdev->host;
1711 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1712 blk_status_t ret;
1713 int reason;
1714
1715 WARN_ON_ONCE(cmd->budget_token < 0);
1716
1717 /*
1718 * If the device is not in running state we will reject some or all
1719 * commands.
1720 */
1721 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1722 ret = scsi_device_state_check(sdev, req);
1723 if (ret != BLK_STS_OK)
1724 goto out_put_budget;
1725 }
1726
1727 ret = BLK_STS_RESOURCE;
1728 if (!scsi_target_queue_ready(shost, sdev))
1729 goto out_put_budget;
1730 if (unlikely(scsi_host_in_recovery(shost))) {
1731 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1732 ret = BLK_STS_OFFLINE;
1733 goto out_dec_target_busy;
1734 }
1735 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1736 goto out_dec_target_busy;
1737
1738 if (!(req->rq_flags & RQF_DONTPREP)) {
1739 ret = scsi_prepare_cmd(req);
1740 if (ret != BLK_STS_OK)
1741 goto out_dec_host_busy;
1742 req->rq_flags |= RQF_DONTPREP;
1743 } else {
1744 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1745 }
1746
1747 cmd->flags &= SCMD_PRESERVED_FLAGS;
1748 if (sdev->simple_tags)
1749 cmd->flags |= SCMD_TAGGED;
1750 if (bd->last)
1751 cmd->flags |= SCMD_LAST;
1752
1753 scsi_set_resid(cmd, 0);
1754 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1755 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1756
1757 blk_mq_start_request(req);
1758 reason = scsi_dispatch_cmd(cmd);
1759 if (reason) {
1760 scsi_set_blocked(cmd, reason);
1761 ret = BLK_STS_RESOURCE;
1762 goto out_dec_host_busy;
1763 }
1764
1765 atomic_inc(&cmd->device->iorequest_cnt);
1766 return BLK_STS_OK;
1767
1768out_dec_host_busy:
1769 scsi_dec_host_busy(shost, cmd);
1770out_dec_target_busy:
1771 if (scsi_target(sdev)->can_queue > 0)
1772 atomic_dec(&scsi_target(sdev)->target_busy);
1773out_put_budget:
1774 scsi_mq_put_budget(q, cmd->budget_token);
1775 cmd->budget_token = -1;
1776 switch (ret) {
1777 case BLK_STS_OK:
1778 break;
1779 case BLK_STS_RESOURCE:
1780 case BLK_STS_ZONE_RESOURCE:
1781 if (scsi_device_blocked(sdev))
1782 ret = BLK_STS_DEV_RESOURCE;
1783 break;
1784 case BLK_STS_AGAIN:
1785 cmd->result = DID_BUS_BUSY << 16;
1786 if (req->rq_flags & RQF_DONTPREP)
1787 scsi_mq_uninit_cmd(cmd);
1788 break;
1789 default:
1790 if (unlikely(!scsi_device_online(sdev)))
1791 cmd->result = DID_NO_CONNECT << 16;
1792 else
1793 cmd->result = DID_ERROR << 16;
1794 /*
1795 * Make sure to release all allocated resources when
1796 * we hit an error, as we will never see this command
1797 * again.
1798 */
1799 if (req->rq_flags & RQF_DONTPREP)
1800 scsi_mq_uninit_cmd(cmd);
1801 scsi_run_queue_async(sdev);
1802 break;
1803 }
1804 return ret;
1805}
1806
1807static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1808 unsigned int hctx_idx, unsigned int numa_node)
1809{
1810 struct Scsi_Host *shost = set->driver_data;
1811 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1812 struct scatterlist *sg;
1813 int ret = 0;
1814
1815 cmd->sense_buffer =
1816 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1817 if (!cmd->sense_buffer)
1818 return -ENOMEM;
1819
1820 if (scsi_host_get_prot(shost)) {
1821 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1822 shost->hostt->cmd_size;
1823 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1824 }
1825
1826 if (shost->hostt->init_cmd_priv) {
1827 ret = shost->hostt->init_cmd_priv(shost, cmd);
1828 if (ret < 0)
1829 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1830 }
1831
1832 return ret;
1833}
1834
1835static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1836 unsigned int hctx_idx)
1837{
1838 struct Scsi_Host *shost = set->driver_data;
1839 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1840
1841 if (shost->hostt->exit_cmd_priv)
1842 shost->hostt->exit_cmd_priv(shost, cmd);
1843 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1844}
1845
1846
1847static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1848{
1849 struct Scsi_Host *shost = hctx->driver_data;
1850
1851 if (shost->hostt->mq_poll)
1852 return shost->hostt->mq_poll(shost, hctx->queue_num);
1853
1854 return 0;
1855}
1856
1857static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1858 unsigned int hctx_idx)
1859{
1860 struct Scsi_Host *shost = data;
1861
1862 hctx->driver_data = shost;
1863 return 0;
1864}
1865
1866static void scsi_map_queues(struct blk_mq_tag_set *set)
1867{
1868 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1869
1870 if (shost->hostt->map_queues)
1871 return shost->hostt->map_queues(shost);
1872 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1873}
1874
1875void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1876{
1877 struct device *dev = shost->dma_dev;
1878
1879 /*
1880 * this limit is imposed by hardware restrictions
1881 */
1882 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1883 SG_MAX_SEGMENTS));
1884
1885 if (scsi_host_prot_dma(shost)) {
1886 shost->sg_prot_tablesize =
1887 min_not_zero(shost->sg_prot_tablesize,
1888 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1889 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1890 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1891 }
1892
1893 blk_queue_max_hw_sectors(q, shost->max_sectors);
1894 blk_queue_segment_boundary(q, shost->dma_boundary);
1895 dma_set_seg_boundary(dev, shost->dma_boundary);
1896
1897 blk_queue_max_segment_size(q, shost->max_segment_size);
1898 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1899 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1900
1901 /*
1902 * Set a reasonable default alignment: The larger of 32-byte (dword),
1903 * which is a common minimum for HBAs, and the minimum DMA alignment,
1904 * which is set by the platform.
1905 *
1906 * Devices that require a bigger alignment can increase it later.
1907 */
1908 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1909}
1910EXPORT_SYMBOL_GPL(__scsi_init_queue);
1911
1912static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1913 .get_budget = scsi_mq_get_budget,
1914 .put_budget = scsi_mq_put_budget,
1915 .queue_rq = scsi_queue_rq,
1916 .complete = scsi_complete,
1917 .timeout = scsi_timeout,
1918#ifdef CONFIG_BLK_DEBUG_FS
1919 .show_rq = scsi_show_rq,
1920#endif
1921 .init_request = scsi_mq_init_request,
1922 .exit_request = scsi_mq_exit_request,
1923 .cleanup_rq = scsi_cleanup_rq,
1924 .busy = scsi_mq_lld_busy,
1925 .map_queues = scsi_map_queues,
1926 .init_hctx = scsi_init_hctx,
1927 .poll = scsi_mq_poll,
1928 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1929 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1930};
1931
1932
1933static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1934{
1935 struct Scsi_Host *shost = hctx->driver_data;
1936
1937 shost->hostt->commit_rqs(shost, hctx->queue_num);
1938}
1939
1940static const struct blk_mq_ops scsi_mq_ops = {
1941 .get_budget = scsi_mq_get_budget,
1942 .put_budget = scsi_mq_put_budget,
1943 .queue_rq = scsi_queue_rq,
1944 .commit_rqs = scsi_commit_rqs,
1945 .complete = scsi_complete,
1946 .timeout = scsi_timeout,
1947#ifdef CONFIG_BLK_DEBUG_FS
1948 .show_rq = scsi_show_rq,
1949#endif
1950 .init_request = scsi_mq_init_request,
1951 .exit_request = scsi_mq_exit_request,
1952 .cleanup_rq = scsi_cleanup_rq,
1953 .busy = scsi_mq_lld_busy,
1954 .map_queues = scsi_map_queues,
1955 .init_hctx = scsi_init_hctx,
1956 .poll = scsi_mq_poll,
1957 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1958 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1959};
1960
1961int scsi_mq_setup_tags(struct Scsi_Host *shost)
1962{
1963 unsigned int cmd_size, sgl_size;
1964 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1965
1966 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1967 scsi_mq_inline_sgl_size(shost));
1968 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1969 if (scsi_host_get_prot(shost))
1970 cmd_size += sizeof(struct scsi_data_buffer) +
1971 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1972
1973 memset(tag_set, 0, sizeof(*tag_set));
1974 if (shost->hostt->commit_rqs)
1975 tag_set->ops = &scsi_mq_ops;
1976 else
1977 tag_set->ops = &scsi_mq_ops_no_commit;
1978 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1979 tag_set->nr_maps = shost->nr_maps ? : 1;
1980 tag_set->queue_depth = shost->can_queue;
1981 tag_set->cmd_size = cmd_size;
1982 tag_set->numa_node = dev_to_node(shost->dma_dev);
1983 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1984 tag_set->flags |=
1985 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1986 tag_set->driver_data = shost;
1987 if (shost->host_tagset)
1988 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1989
1990 return blk_mq_alloc_tag_set(tag_set);
1991}
1992
1993void scsi_mq_free_tags(struct kref *kref)
1994{
1995 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
1996 tagset_refcnt);
1997
1998 blk_mq_free_tag_set(&shost->tag_set);
1999 complete(&shost->tagset_freed);
2000}
2001
2002/**
2003 * scsi_device_from_queue - return sdev associated with a request_queue
2004 * @q: The request queue to return the sdev from
2005 *
2006 * Return the sdev associated with a request queue or NULL if the
2007 * request_queue does not reference a SCSI device.
2008 */
2009struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2010{
2011 struct scsi_device *sdev = NULL;
2012
2013 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2014 q->mq_ops == &scsi_mq_ops)
2015 sdev = q->queuedata;
2016 if (!sdev || !get_device(&sdev->sdev_gendev))
2017 sdev = NULL;
2018
2019 return sdev;
2020}
2021/*
2022 * pktcdvd should have been integrated into the SCSI layers, but for historical
2023 * reasons like the old IDE driver it isn't. This export allows it to safely
2024 * probe if a given device is a SCSI one and only attach to that.
2025 */
2026#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2027EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2028#endif
2029
2030/**
2031 * scsi_block_requests - Utility function used by low-level drivers to prevent
2032 * further commands from being queued to the device.
2033 * @shost: host in question
2034 *
2035 * There is no timer nor any other means by which the requests get unblocked
2036 * other than the low-level driver calling scsi_unblock_requests().
2037 */
2038void scsi_block_requests(struct Scsi_Host *shost)
2039{
2040 shost->host_self_blocked = 1;
2041}
2042EXPORT_SYMBOL(scsi_block_requests);
2043
2044/**
2045 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2046 * further commands to be queued to the device.
2047 * @shost: host in question
2048 *
2049 * There is no timer nor any other means by which the requests get unblocked
2050 * other than the low-level driver calling scsi_unblock_requests(). This is done
2051 * as an API function so that changes to the internals of the scsi mid-layer
2052 * won't require wholesale changes to drivers that use this feature.
2053 */
2054void scsi_unblock_requests(struct Scsi_Host *shost)
2055{
2056 shost->host_self_blocked = 0;
2057 scsi_run_host_queues(shost);
2058}
2059EXPORT_SYMBOL(scsi_unblock_requests);
2060
2061void scsi_exit_queue(void)
2062{
2063 kmem_cache_destroy(scsi_sense_cache);
2064}
2065
2066/**
2067 * scsi_mode_select - issue a mode select
2068 * @sdev: SCSI device to be queried
2069 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2070 * @sp: Save page bit (0 == don't save, 1 == save)
2071 * @buffer: request buffer (may not be smaller than eight bytes)
2072 * @len: length of request buffer.
2073 * @timeout: command timeout
2074 * @retries: number of retries before failing
2075 * @data: returns a structure abstracting the mode header data
2076 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2077 * must be SCSI_SENSE_BUFFERSIZE big.
2078 *
2079 * Returns zero if successful; negative error number or scsi
2080 * status on error
2081 *
2082 */
2083int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2084 unsigned char *buffer, int len, int timeout, int retries,
2085 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2086{
2087 unsigned char cmd[10];
2088 unsigned char *real_buffer;
2089 int ret;
2090
2091 memset(cmd, 0, sizeof(cmd));
2092 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2093
2094 /*
2095 * Use MODE SELECT(10) if the device asked for it or if the mode page
2096 * and the mode select header cannot fit within the maximumm 255 bytes
2097 * of the MODE SELECT(6) command.
2098 */
2099 if (sdev->use_10_for_ms ||
2100 len + 4 > 255 ||
2101 data->block_descriptor_length > 255) {
2102 if (len > 65535 - 8)
2103 return -EINVAL;
2104 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2105 if (!real_buffer)
2106 return -ENOMEM;
2107 memcpy(real_buffer + 8, buffer, len);
2108 len += 8;
2109 real_buffer[0] = 0;
2110 real_buffer[1] = 0;
2111 real_buffer[2] = data->medium_type;
2112 real_buffer[3] = data->device_specific;
2113 real_buffer[4] = data->longlba ? 0x01 : 0;
2114 real_buffer[5] = 0;
2115 put_unaligned_be16(data->block_descriptor_length,
2116 &real_buffer[6]);
2117
2118 cmd[0] = MODE_SELECT_10;
2119 put_unaligned_be16(len, &cmd[7]);
2120 } else {
2121 if (data->longlba)
2122 return -EINVAL;
2123
2124 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2125 if (!real_buffer)
2126 return -ENOMEM;
2127 memcpy(real_buffer + 4, buffer, len);
2128 len += 4;
2129 real_buffer[0] = 0;
2130 real_buffer[1] = data->medium_type;
2131 real_buffer[2] = data->device_specific;
2132 real_buffer[3] = data->block_descriptor_length;
2133
2134 cmd[0] = MODE_SELECT;
2135 cmd[4] = len;
2136 }
2137
2138 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2139 sshdr, timeout, retries, NULL);
2140 kfree(real_buffer);
2141 return ret;
2142}
2143EXPORT_SYMBOL_GPL(scsi_mode_select);
2144
2145/**
2146 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2147 * @sdev: SCSI device to be queried
2148 * @dbd: set to prevent mode sense from returning block descriptors
2149 * @modepage: mode page being requested
2150 * @buffer: request buffer (may not be smaller than eight bytes)
2151 * @len: length of request buffer.
2152 * @timeout: command timeout
2153 * @retries: number of retries before failing
2154 * @data: returns a structure abstracting the mode header data
2155 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2156 * must be SCSI_SENSE_BUFFERSIZE big.
2157 *
2158 * Returns zero if successful, or a negative error number on failure
2159 */
2160int
2161scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2162 unsigned char *buffer, int len, int timeout, int retries,
2163 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2164{
2165 unsigned char cmd[12];
2166 int use_10_for_ms;
2167 int header_length;
2168 int result, retry_count = retries;
2169 struct scsi_sense_hdr my_sshdr;
2170
2171 memset(data, 0, sizeof(*data));
2172 memset(&cmd[0], 0, 12);
2173
2174 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2175 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2176 cmd[2] = modepage;
2177
2178 /* caller might not be interested in sense, but we need it */
2179 if (!sshdr)
2180 sshdr = &my_sshdr;
2181
2182 retry:
2183 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2184
2185 if (use_10_for_ms) {
2186 if (len < 8 || len > 65535)
2187 return -EINVAL;
2188
2189 cmd[0] = MODE_SENSE_10;
2190 put_unaligned_be16(len, &cmd[7]);
2191 header_length = 8;
2192 } else {
2193 if (len < 4)
2194 return -EINVAL;
2195
2196 cmd[0] = MODE_SENSE;
2197 cmd[4] = len;
2198 header_length = 4;
2199 }
2200
2201 memset(buffer, 0, len);
2202
2203 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2204 sshdr, timeout, retries, NULL);
2205 if (result < 0)
2206 return result;
2207
2208 /* This code looks awful: what it's doing is making sure an
2209 * ILLEGAL REQUEST sense return identifies the actual command
2210 * byte as the problem. MODE_SENSE commands can return
2211 * ILLEGAL REQUEST if the code page isn't supported */
2212
2213 if (!scsi_status_is_good(result)) {
2214 if (scsi_sense_valid(sshdr)) {
2215 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2216 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2217 /*
2218 * Invalid command operation code: retry using
2219 * MODE SENSE(6) if this was a MODE SENSE(10)
2220 * request, except if the request mode page is
2221 * too large for MODE SENSE single byte
2222 * allocation length field.
2223 */
2224 if (use_10_for_ms) {
2225 if (len > 255)
2226 return -EIO;
2227 sdev->use_10_for_ms = 0;
2228 goto retry;
2229 }
2230 }
2231 if (scsi_status_is_check_condition(result) &&
2232 sshdr->sense_key == UNIT_ATTENTION &&
2233 retry_count) {
2234 retry_count--;
2235 goto retry;
2236 }
2237 }
2238 return -EIO;
2239 }
2240 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2241 (modepage == 6 || modepage == 8))) {
2242 /* Initio breakage? */
2243 header_length = 0;
2244 data->length = 13;
2245 data->medium_type = 0;
2246 data->device_specific = 0;
2247 data->longlba = 0;
2248 data->block_descriptor_length = 0;
2249 } else if (use_10_for_ms) {
2250 data->length = get_unaligned_be16(&buffer[0]) + 2;
2251 data->medium_type = buffer[2];
2252 data->device_specific = buffer[3];
2253 data->longlba = buffer[4] & 0x01;
2254 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2255 } else {
2256 data->length = buffer[0] + 1;
2257 data->medium_type = buffer[1];
2258 data->device_specific = buffer[2];
2259 data->block_descriptor_length = buffer[3];
2260 }
2261 data->header_length = header_length;
2262
2263 return 0;
2264}
2265EXPORT_SYMBOL(scsi_mode_sense);
2266
2267/**
2268 * scsi_test_unit_ready - test if unit is ready
2269 * @sdev: scsi device to change the state of.
2270 * @timeout: command timeout
2271 * @retries: number of retries before failing
2272 * @sshdr: outpout pointer for decoded sense information.
2273 *
2274 * Returns zero if unsuccessful or an error if TUR failed. For
2275 * removable media, UNIT_ATTENTION sets ->changed flag.
2276 **/
2277int
2278scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2279 struct scsi_sense_hdr *sshdr)
2280{
2281 char cmd[] = {
2282 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2283 };
2284 int result;
2285
2286 /* try to eat the UNIT_ATTENTION if there are enough retries */
2287 do {
2288 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2289 timeout, 1, NULL);
2290 if (sdev->removable && scsi_sense_valid(sshdr) &&
2291 sshdr->sense_key == UNIT_ATTENTION)
2292 sdev->changed = 1;
2293 } while (scsi_sense_valid(sshdr) &&
2294 sshdr->sense_key == UNIT_ATTENTION && --retries);
2295
2296 return result;
2297}
2298EXPORT_SYMBOL(scsi_test_unit_ready);
2299
2300/**
2301 * scsi_device_set_state - Take the given device through the device state model.
2302 * @sdev: scsi device to change the state of.
2303 * @state: state to change to.
2304 *
2305 * Returns zero if successful or an error if the requested
2306 * transition is illegal.
2307 */
2308int
2309scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2310{
2311 enum scsi_device_state oldstate = sdev->sdev_state;
2312
2313 if (state == oldstate)
2314 return 0;
2315
2316 switch (state) {
2317 case SDEV_CREATED:
2318 switch (oldstate) {
2319 case SDEV_CREATED_BLOCK:
2320 break;
2321 default:
2322 goto illegal;
2323 }
2324 break;
2325
2326 case SDEV_RUNNING:
2327 switch (oldstate) {
2328 case SDEV_CREATED:
2329 case SDEV_OFFLINE:
2330 case SDEV_TRANSPORT_OFFLINE:
2331 case SDEV_QUIESCE:
2332 case SDEV_BLOCK:
2333 break;
2334 default:
2335 goto illegal;
2336 }
2337 break;
2338
2339 case SDEV_QUIESCE:
2340 switch (oldstate) {
2341 case SDEV_RUNNING:
2342 case SDEV_OFFLINE:
2343 case SDEV_TRANSPORT_OFFLINE:
2344 break;
2345 default:
2346 goto illegal;
2347 }
2348 break;
2349
2350 case SDEV_OFFLINE:
2351 case SDEV_TRANSPORT_OFFLINE:
2352 switch (oldstate) {
2353 case SDEV_CREATED:
2354 case SDEV_RUNNING:
2355 case SDEV_QUIESCE:
2356 case SDEV_BLOCK:
2357 break;
2358 default:
2359 goto illegal;
2360 }
2361 break;
2362
2363 case SDEV_BLOCK:
2364 switch (oldstate) {
2365 case SDEV_RUNNING:
2366 case SDEV_CREATED_BLOCK:
2367 case SDEV_QUIESCE:
2368 case SDEV_OFFLINE:
2369 break;
2370 default:
2371 goto illegal;
2372 }
2373 break;
2374
2375 case SDEV_CREATED_BLOCK:
2376 switch (oldstate) {
2377 case SDEV_CREATED:
2378 break;
2379 default:
2380 goto illegal;
2381 }
2382 break;
2383
2384 case SDEV_CANCEL:
2385 switch (oldstate) {
2386 case SDEV_CREATED:
2387 case SDEV_RUNNING:
2388 case SDEV_QUIESCE:
2389 case SDEV_OFFLINE:
2390 case SDEV_TRANSPORT_OFFLINE:
2391 break;
2392 default:
2393 goto illegal;
2394 }
2395 break;
2396
2397 case SDEV_DEL:
2398 switch (oldstate) {
2399 case SDEV_CREATED:
2400 case SDEV_RUNNING:
2401 case SDEV_OFFLINE:
2402 case SDEV_TRANSPORT_OFFLINE:
2403 case SDEV_CANCEL:
2404 case SDEV_BLOCK:
2405 case SDEV_CREATED_BLOCK:
2406 break;
2407 default:
2408 goto illegal;
2409 }
2410 break;
2411
2412 }
2413 sdev->offline_already = false;
2414 sdev->sdev_state = state;
2415 return 0;
2416
2417 illegal:
2418 SCSI_LOG_ERROR_RECOVERY(1,
2419 sdev_printk(KERN_ERR, sdev,
2420 "Illegal state transition %s->%s",
2421 scsi_device_state_name(oldstate),
2422 scsi_device_state_name(state))
2423 );
2424 return -EINVAL;
2425}
2426EXPORT_SYMBOL(scsi_device_set_state);
2427
2428/**
2429 * scsi_evt_emit - emit a single SCSI device uevent
2430 * @sdev: associated SCSI device
2431 * @evt: event to emit
2432 *
2433 * Send a single uevent (scsi_event) to the associated scsi_device.
2434 */
2435static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2436{
2437 int idx = 0;
2438 char *envp[3];
2439
2440 switch (evt->evt_type) {
2441 case SDEV_EVT_MEDIA_CHANGE:
2442 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2443 break;
2444 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2445 scsi_rescan_device(&sdev->sdev_gendev);
2446 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2447 break;
2448 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2449 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2450 break;
2451 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2452 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2453 break;
2454 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2455 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2456 break;
2457 case SDEV_EVT_LUN_CHANGE_REPORTED:
2458 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2459 break;
2460 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2461 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2462 break;
2463 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2464 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2465 break;
2466 default:
2467 /* do nothing */
2468 break;
2469 }
2470
2471 envp[idx++] = NULL;
2472
2473 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2474}
2475
2476/**
2477 * scsi_evt_thread - send a uevent for each scsi event
2478 * @work: work struct for scsi_device
2479 *
2480 * Dispatch queued events to their associated scsi_device kobjects
2481 * as uevents.
2482 */
2483void scsi_evt_thread(struct work_struct *work)
2484{
2485 struct scsi_device *sdev;
2486 enum scsi_device_event evt_type;
2487 LIST_HEAD(event_list);
2488
2489 sdev = container_of(work, struct scsi_device, event_work);
2490
2491 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2492 if (test_and_clear_bit(evt_type, sdev->pending_events))
2493 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2494
2495 while (1) {
2496 struct scsi_event *evt;
2497 struct list_head *this, *tmp;
2498 unsigned long flags;
2499
2500 spin_lock_irqsave(&sdev->list_lock, flags);
2501 list_splice_init(&sdev->event_list, &event_list);
2502 spin_unlock_irqrestore(&sdev->list_lock, flags);
2503
2504 if (list_empty(&event_list))
2505 break;
2506
2507 list_for_each_safe(this, tmp, &event_list) {
2508 evt = list_entry(this, struct scsi_event, node);
2509 list_del(&evt->node);
2510 scsi_evt_emit(sdev, evt);
2511 kfree(evt);
2512 }
2513 }
2514}
2515
2516/**
2517 * sdev_evt_send - send asserted event to uevent thread
2518 * @sdev: scsi_device event occurred on
2519 * @evt: event to send
2520 *
2521 * Assert scsi device event asynchronously.
2522 */
2523void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2524{
2525 unsigned long flags;
2526
2527#if 0
2528 /* FIXME: currently this check eliminates all media change events
2529 * for polled devices. Need to update to discriminate between AN
2530 * and polled events */
2531 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2532 kfree(evt);
2533 return;
2534 }
2535#endif
2536
2537 spin_lock_irqsave(&sdev->list_lock, flags);
2538 list_add_tail(&evt->node, &sdev->event_list);
2539 schedule_work(&sdev->event_work);
2540 spin_unlock_irqrestore(&sdev->list_lock, flags);
2541}
2542EXPORT_SYMBOL_GPL(sdev_evt_send);
2543
2544/**
2545 * sdev_evt_alloc - allocate a new scsi event
2546 * @evt_type: type of event to allocate
2547 * @gfpflags: GFP flags for allocation
2548 *
2549 * Allocates and returns a new scsi_event.
2550 */
2551struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2552 gfp_t gfpflags)
2553{
2554 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2555 if (!evt)
2556 return NULL;
2557
2558 evt->evt_type = evt_type;
2559 INIT_LIST_HEAD(&evt->node);
2560
2561 /* evt_type-specific initialization, if any */
2562 switch (evt_type) {
2563 case SDEV_EVT_MEDIA_CHANGE:
2564 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2565 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2566 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2567 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2568 case SDEV_EVT_LUN_CHANGE_REPORTED:
2569 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2570 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2571 default:
2572 /* do nothing */
2573 break;
2574 }
2575
2576 return evt;
2577}
2578EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2579
2580/**
2581 * sdev_evt_send_simple - send asserted event to uevent thread
2582 * @sdev: scsi_device event occurred on
2583 * @evt_type: type of event to send
2584 * @gfpflags: GFP flags for allocation
2585 *
2586 * Assert scsi device event asynchronously, given an event type.
2587 */
2588void sdev_evt_send_simple(struct scsi_device *sdev,
2589 enum scsi_device_event evt_type, gfp_t gfpflags)
2590{
2591 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2592 if (!evt) {
2593 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2594 evt_type);
2595 return;
2596 }
2597
2598 sdev_evt_send(sdev, evt);
2599}
2600EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2601
2602/**
2603 * scsi_device_quiesce - Block all commands except power management.
2604 * @sdev: scsi device to quiesce.
2605 *
2606 * This works by trying to transition to the SDEV_QUIESCE state
2607 * (which must be a legal transition). When the device is in this
2608 * state, only power management requests will be accepted, all others will
2609 * be deferred.
2610 *
2611 * Must be called with user context, may sleep.
2612 *
2613 * Returns zero if unsuccessful or an error if not.
2614 */
2615int
2616scsi_device_quiesce(struct scsi_device *sdev)
2617{
2618 struct request_queue *q = sdev->request_queue;
2619 int err;
2620
2621 /*
2622 * It is allowed to call scsi_device_quiesce() multiple times from
2623 * the same context but concurrent scsi_device_quiesce() calls are
2624 * not allowed.
2625 */
2626 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2627
2628 if (sdev->quiesced_by == current)
2629 return 0;
2630
2631 blk_set_pm_only(q);
2632
2633 blk_mq_freeze_queue(q);
2634 /*
2635 * Ensure that the effect of blk_set_pm_only() will be visible
2636 * for percpu_ref_tryget() callers that occur after the queue
2637 * unfreeze even if the queue was already frozen before this function
2638 * was called. See also https://lwn.net/Articles/573497/.
2639 */
2640 synchronize_rcu();
2641 blk_mq_unfreeze_queue(q);
2642
2643 mutex_lock(&sdev->state_mutex);
2644 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2645 if (err == 0)
2646 sdev->quiesced_by = current;
2647 else
2648 blk_clear_pm_only(q);
2649 mutex_unlock(&sdev->state_mutex);
2650
2651 return err;
2652}
2653EXPORT_SYMBOL(scsi_device_quiesce);
2654
2655/**
2656 * scsi_device_resume - Restart user issued commands to a quiesced device.
2657 * @sdev: scsi device to resume.
2658 *
2659 * Moves the device from quiesced back to running and restarts the
2660 * queues.
2661 *
2662 * Must be called with user context, may sleep.
2663 */
2664void scsi_device_resume(struct scsi_device *sdev)
2665{
2666 /* check if the device state was mutated prior to resume, and if
2667 * so assume the state is being managed elsewhere (for example
2668 * device deleted during suspend)
2669 */
2670 mutex_lock(&sdev->state_mutex);
2671 if (sdev->sdev_state == SDEV_QUIESCE)
2672 scsi_device_set_state(sdev, SDEV_RUNNING);
2673 if (sdev->quiesced_by) {
2674 sdev->quiesced_by = NULL;
2675 blk_clear_pm_only(sdev->request_queue);
2676 }
2677 mutex_unlock(&sdev->state_mutex);
2678}
2679EXPORT_SYMBOL(scsi_device_resume);
2680
2681static void
2682device_quiesce_fn(struct scsi_device *sdev, void *data)
2683{
2684 scsi_device_quiesce(sdev);
2685}
2686
2687void
2688scsi_target_quiesce(struct scsi_target *starget)
2689{
2690 starget_for_each_device(starget, NULL, device_quiesce_fn);
2691}
2692EXPORT_SYMBOL(scsi_target_quiesce);
2693
2694static void
2695device_resume_fn(struct scsi_device *sdev, void *data)
2696{
2697 scsi_device_resume(sdev);
2698}
2699
2700void
2701scsi_target_resume(struct scsi_target *starget)
2702{
2703 starget_for_each_device(starget, NULL, device_resume_fn);
2704}
2705EXPORT_SYMBOL(scsi_target_resume);
2706
2707static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2708{
2709 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2710 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2711
2712 return 0;
2713}
2714
2715void scsi_start_queue(struct scsi_device *sdev)
2716{
2717 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2718 blk_mq_unquiesce_queue(sdev->request_queue);
2719}
2720
2721static void scsi_stop_queue(struct scsi_device *sdev, bool nowait)
2722{
2723 /*
2724 * The atomic variable of ->queue_stopped covers that
2725 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2726 *
2727 * However, we still need to wait until quiesce is done
2728 * in case that queue has been stopped.
2729 */
2730 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) {
2731 if (nowait)
2732 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2733 else
2734 blk_mq_quiesce_queue(sdev->request_queue);
2735 } else {
2736 if (!nowait)
2737 blk_mq_wait_quiesce_done(sdev->request_queue->tag_set);
2738 }
2739}
2740
2741/**
2742 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2743 * @sdev: device to block
2744 *
2745 * Pause SCSI command processing on the specified device. Does not sleep.
2746 *
2747 * Returns zero if successful or a negative error code upon failure.
2748 *
2749 * Notes:
2750 * This routine transitions the device to the SDEV_BLOCK state (which must be
2751 * a legal transition). When the device is in this state, command processing
2752 * is paused until the device leaves the SDEV_BLOCK state. See also
2753 * scsi_internal_device_unblock_nowait().
2754 */
2755int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2756{
2757 int ret = __scsi_internal_device_block_nowait(sdev);
2758
2759 /*
2760 * The device has transitioned to SDEV_BLOCK. Stop the
2761 * block layer from calling the midlayer with this device's
2762 * request queue.
2763 */
2764 if (!ret)
2765 scsi_stop_queue(sdev, true);
2766 return ret;
2767}
2768EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2769
2770/**
2771 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2772 * @sdev: device to block
2773 *
2774 * Pause SCSI command processing on the specified device and wait until all
2775 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2776 *
2777 * Returns zero if successful or a negative error code upon failure.
2778 *
2779 * Note:
2780 * This routine transitions the device to the SDEV_BLOCK state (which must be
2781 * a legal transition). When the device is in this state, command processing
2782 * is paused until the device leaves the SDEV_BLOCK state. See also
2783 * scsi_internal_device_unblock().
2784 */
2785static int scsi_internal_device_block(struct scsi_device *sdev)
2786{
2787 int err;
2788
2789 mutex_lock(&sdev->state_mutex);
2790 err = __scsi_internal_device_block_nowait(sdev);
2791 if (err == 0)
2792 scsi_stop_queue(sdev, false);
2793 mutex_unlock(&sdev->state_mutex);
2794
2795 return err;
2796}
2797
2798/**
2799 * scsi_internal_device_unblock_nowait - resume a device after a block request
2800 * @sdev: device to resume
2801 * @new_state: state to set the device to after unblocking
2802 *
2803 * Restart the device queue for a previously suspended SCSI device. Does not
2804 * sleep.
2805 *
2806 * Returns zero if successful or a negative error code upon failure.
2807 *
2808 * Notes:
2809 * This routine transitions the device to the SDEV_RUNNING state or to one of
2810 * the offline states (which must be a legal transition) allowing the midlayer
2811 * to goose the queue for this device.
2812 */
2813int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2814 enum scsi_device_state new_state)
2815{
2816 switch (new_state) {
2817 case SDEV_RUNNING:
2818 case SDEV_TRANSPORT_OFFLINE:
2819 break;
2820 default:
2821 return -EINVAL;
2822 }
2823
2824 /*
2825 * Try to transition the scsi device to SDEV_RUNNING or one of the
2826 * offlined states and goose the device queue if successful.
2827 */
2828 switch (sdev->sdev_state) {
2829 case SDEV_BLOCK:
2830 case SDEV_TRANSPORT_OFFLINE:
2831 sdev->sdev_state = new_state;
2832 break;
2833 case SDEV_CREATED_BLOCK:
2834 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2835 new_state == SDEV_OFFLINE)
2836 sdev->sdev_state = new_state;
2837 else
2838 sdev->sdev_state = SDEV_CREATED;
2839 break;
2840 case SDEV_CANCEL:
2841 case SDEV_OFFLINE:
2842 break;
2843 default:
2844 return -EINVAL;
2845 }
2846 scsi_start_queue(sdev);
2847
2848 return 0;
2849}
2850EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2851
2852/**
2853 * scsi_internal_device_unblock - resume a device after a block request
2854 * @sdev: device to resume
2855 * @new_state: state to set the device to after unblocking
2856 *
2857 * Restart the device queue for a previously suspended SCSI device. May sleep.
2858 *
2859 * Returns zero if successful or a negative error code upon failure.
2860 *
2861 * Notes:
2862 * This routine transitions the device to the SDEV_RUNNING state or to one of
2863 * the offline states (which must be a legal transition) allowing the midlayer
2864 * to goose the queue for this device.
2865 */
2866static int scsi_internal_device_unblock(struct scsi_device *sdev,
2867 enum scsi_device_state new_state)
2868{
2869 int ret;
2870
2871 mutex_lock(&sdev->state_mutex);
2872 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2873 mutex_unlock(&sdev->state_mutex);
2874
2875 return ret;
2876}
2877
2878static void
2879device_block(struct scsi_device *sdev, void *data)
2880{
2881 int ret;
2882
2883 ret = scsi_internal_device_block(sdev);
2884
2885 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2886 dev_name(&sdev->sdev_gendev), ret);
2887}
2888
2889static int
2890target_block(struct device *dev, void *data)
2891{
2892 if (scsi_is_target_device(dev))
2893 starget_for_each_device(to_scsi_target(dev), NULL,
2894 device_block);
2895 return 0;
2896}
2897
2898void
2899scsi_target_block(struct device *dev)
2900{
2901 if (scsi_is_target_device(dev))
2902 starget_for_each_device(to_scsi_target(dev), NULL,
2903 device_block);
2904 else
2905 device_for_each_child(dev, NULL, target_block);
2906}
2907EXPORT_SYMBOL_GPL(scsi_target_block);
2908
2909static void
2910device_unblock(struct scsi_device *sdev, void *data)
2911{
2912 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2913}
2914
2915static int
2916target_unblock(struct device *dev, void *data)
2917{
2918 if (scsi_is_target_device(dev))
2919 starget_for_each_device(to_scsi_target(dev), data,
2920 device_unblock);
2921 return 0;
2922}
2923
2924void
2925scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2926{
2927 if (scsi_is_target_device(dev))
2928 starget_for_each_device(to_scsi_target(dev), &new_state,
2929 device_unblock);
2930 else
2931 device_for_each_child(dev, &new_state, target_unblock);
2932}
2933EXPORT_SYMBOL_GPL(scsi_target_unblock);
2934
2935int
2936scsi_host_block(struct Scsi_Host *shost)
2937{
2938 struct scsi_device *sdev;
2939 int ret = 0;
2940
2941 /*
2942 * Call scsi_internal_device_block_nowait so we can avoid
2943 * calling synchronize_rcu() for each LUN.
2944 */
2945 shost_for_each_device(sdev, shost) {
2946 mutex_lock(&sdev->state_mutex);
2947 ret = scsi_internal_device_block_nowait(sdev);
2948 mutex_unlock(&sdev->state_mutex);
2949 if (ret) {
2950 scsi_device_put(sdev);
2951 break;
2952 }
2953 }
2954
2955 /*
2956 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2957 * calling synchronize_rcu() once is enough.
2958 */
2959 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2960
2961 if (!ret)
2962 synchronize_rcu();
2963
2964 return ret;
2965}
2966EXPORT_SYMBOL_GPL(scsi_host_block);
2967
2968int
2969scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2970{
2971 struct scsi_device *sdev;
2972 int ret = 0;
2973
2974 shost_for_each_device(sdev, shost) {
2975 ret = scsi_internal_device_unblock(sdev, new_state);
2976 if (ret) {
2977 scsi_device_put(sdev);
2978 break;
2979 }
2980 }
2981 return ret;
2982}
2983EXPORT_SYMBOL_GPL(scsi_host_unblock);
2984
2985/**
2986 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2987 * @sgl: scatter-gather list
2988 * @sg_count: number of segments in sg
2989 * @offset: offset in bytes into sg, on return offset into the mapped area
2990 * @len: bytes to map, on return number of bytes mapped
2991 *
2992 * Returns virtual address of the start of the mapped page
2993 */
2994void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2995 size_t *offset, size_t *len)
2996{
2997 int i;
2998 size_t sg_len = 0, len_complete = 0;
2999 struct scatterlist *sg;
3000 struct page *page;
3001
3002 WARN_ON(!irqs_disabled());
3003
3004 for_each_sg(sgl, sg, sg_count, i) {
3005 len_complete = sg_len; /* Complete sg-entries */
3006 sg_len += sg->length;
3007 if (sg_len > *offset)
3008 break;
3009 }
3010
3011 if (unlikely(i == sg_count)) {
3012 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3013 "elements %d\n",
3014 __func__, sg_len, *offset, sg_count);
3015 WARN_ON(1);
3016 return NULL;
3017 }
3018
3019 /* Offset starting from the beginning of first page in this sg-entry */
3020 *offset = *offset - len_complete + sg->offset;
3021
3022 /* Assumption: contiguous pages can be accessed as "page + i" */
3023 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3024 *offset &= ~PAGE_MASK;
3025
3026 /* Bytes in this sg-entry from *offset to the end of the page */
3027 sg_len = PAGE_SIZE - *offset;
3028 if (*len > sg_len)
3029 *len = sg_len;
3030
3031 return kmap_atomic(page);
3032}
3033EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3034
3035/**
3036 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3037 * @virt: virtual address to be unmapped
3038 */
3039void scsi_kunmap_atomic_sg(void *virt)
3040{
3041 kunmap_atomic(virt);
3042}
3043EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3044
3045void sdev_disable_disk_events(struct scsi_device *sdev)
3046{
3047 atomic_inc(&sdev->disk_events_disable_depth);
3048}
3049EXPORT_SYMBOL(sdev_disable_disk_events);
3050
3051void sdev_enable_disk_events(struct scsi_device *sdev)
3052{
3053 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3054 return;
3055 atomic_dec(&sdev->disk_events_disable_depth);
3056}
3057EXPORT_SYMBOL(sdev_enable_disk_events);
3058
3059static unsigned char designator_prio(const unsigned char *d)
3060{
3061 if (d[1] & 0x30)
3062 /* not associated with LUN */
3063 return 0;
3064
3065 if (d[3] == 0)
3066 /* invalid length */
3067 return 0;
3068
3069 /*
3070 * Order of preference for lun descriptor:
3071 * - SCSI name string
3072 * - NAA IEEE Registered Extended
3073 * - EUI-64 based 16-byte
3074 * - EUI-64 based 12-byte
3075 * - NAA IEEE Registered
3076 * - NAA IEEE Extended
3077 * - EUI-64 based 8-byte
3078 * - SCSI name string (truncated)
3079 * - T10 Vendor ID
3080 * as longer descriptors reduce the likelyhood
3081 * of identification clashes.
3082 */
3083
3084 switch (d[1] & 0xf) {
3085 case 8:
3086 /* SCSI name string, variable-length UTF-8 */
3087 return 9;
3088 case 3:
3089 switch (d[4] >> 4) {
3090 case 6:
3091 /* NAA registered extended */
3092 return 8;
3093 case 5:
3094 /* NAA registered */
3095 return 5;
3096 case 4:
3097 /* NAA extended */
3098 return 4;
3099 case 3:
3100 /* NAA locally assigned */
3101 return 1;
3102 default:
3103 break;
3104 }
3105 break;
3106 case 2:
3107 switch (d[3]) {
3108 case 16:
3109 /* EUI64-based, 16 byte */
3110 return 7;
3111 case 12:
3112 /* EUI64-based, 12 byte */
3113 return 6;
3114 case 8:
3115 /* EUI64-based, 8 byte */
3116 return 3;
3117 default:
3118 break;
3119 }
3120 break;
3121 case 1:
3122 /* T10 vendor ID */
3123 return 1;
3124 default:
3125 break;
3126 }
3127
3128 return 0;
3129}
3130
3131/**
3132 * scsi_vpd_lun_id - return a unique device identification
3133 * @sdev: SCSI device
3134 * @id: buffer for the identification
3135 * @id_len: length of the buffer
3136 *
3137 * Copies a unique device identification into @id based
3138 * on the information in the VPD page 0x83 of the device.
3139 * The string will be formatted as a SCSI name string.
3140 *
3141 * Returns the length of the identification or error on failure.
3142 * If the identifier is longer than the supplied buffer the actual
3143 * identifier length is returned and the buffer is not zero-padded.
3144 */
3145int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3146{
3147 u8 cur_id_prio = 0;
3148 u8 cur_id_size = 0;
3149 const unsigned char *d, *cur_id_str;
3150 const struct scsi_vpd *vpd_pg83;
3151 int id_size = -EINVAL;
3152
3153 rcu_read_lock();
3154 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3155 if (!vpd_pg83) {
3156 rcu_read_unlock();
3157 return -ENXIO;
3158 }
3159
3160 /* The id string must be at least 20 bytes + terminating NULL byte */
3161 if (id_len < 21) {
3162 rcu_read_unlock();
3163 return -EINVAL;
3164 }
3165
3166 memset(id, 0, id_len);
3167 for (d = vpd_pg83->data + 4;
3168 d < vpd_pg83->data + vpd_pg83->len;
3169 d += d[3] + 4) {
3170 u8 prio = designator_prio(d);
3171
3172 if (prio == 0 || cur_id_prio > prio)
3173 continue;
3174
3175 switch (d[1] & 0xf) {
3176 case 0x1:
3177 /* T10 Vendor ID */
3178 if (cur_id_size > d[3])
3179 break;
3180 cur_id_prio = prio;
3181 cur_id_size = d[3];
3182 if (cur_id_size + 4 > id_len)
3183 cur_id_size = id_len - 4;
3184 cur_id_str = d + 4;
3185 id_size = snprintf(id, id_len, "t10.%*pE",
3186 cur_id_size, cur_id_str);
3187 break;
3188 case 0x2:
3189 /* EUI-64 */
3190 cur_id_prio = prio;
3191 cur_id_size = d[3];
3192 cur_id_str = d + 4;
3193 switch (cur_id_size) {
3194 case 8:
3195 id_size = snprintf(id, id_len,
3196 "eui.%8phN",
3197 cur_id_str);
3198 break;
3199 case 12:
3200 id_size = snprintf(id, id_len,
3201 "eui.%12phN",
3202 cur_id_str);
3203 break;
3204 case 16:
3205 id_size = snprintf(id, id_len,
3206 "eui.%16phN",
3207 cur_id_str);
3208 break;
3209 default:
3210 break;
3211 }
3212 break;
3213 case 0x3:
3214 /* NAA */
3215 cur_id_prio = prio;
3216 cur_id_size = d[3];
3217 cur_id_str = d + 4;
3218 switch (cur_id_size) {
3219 case 8:
3220 id_size = snprintf(id, id_len,
3221 "naa.%8phN",
3222 cur_id_str);
3223 break;
3224 case 16:
3225 id_size = snprintf(id, id_len,
3226 "naa.%16phN",
3227 cur_id_str);
3228 break;
3229 default:
3230 break;
3231 }
3232 break;
3233 case 0x8:
3234 /* SCSI name string */
3235 if (cur_id_size > d[3])
3236 break;
3237 /* Prefer others for truncated descriptor */
3238 if (d[3] > id_len) {
3239 prio = 2;
3240 if (cur_id_prio > prio)
3241 break;
3242 }
3243 cur_id_prio = prio;
3244 cur_id_size = id_size = d[3];
3245 cur_id_str = d + 4;
3246 if (cur_id_size >= id_len)
3247 cur_id_size = id_len - 1;
3248 memcpy(id, cur_id_str, cur_id_size);
3249 break;
3250 default:
3251 break;
3252 }
3253 }
3254 rcu_read_unlock();
3255
3256 return id_size;
3257}
3258EXPORT_SYMBOL(scsi_vpd_lun_id);
3259
3260/*
3261 * scsi_vpd_tpg_id - return a target port group identifier
3262 * @sdev: SCSI device
3263 *
3264 * Returns the Target Port Group identifier from the information
3265 * froom VPD page 0x83 of the device.
3266 *
3267 * Returns the identifier or error on failure.
3268 */
3269int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3270{
3271 const unsigned char *d;
3272 const struct scsi_vpd *vpd_pg83;
3273 int group_id = -EAGAIN, rel_port = -1;
3274
3275 rcu_read_lock();
3276 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3277 if (!vpd_pg83) {
3278 rcu_read_unlock();
3279 return -ENXIO;
3280 }
3281
3282 d = vpd_pg83->data + 4;
3283 while (d < vpd_pg83->data + vpd_pg83->len) {
3284 switch (d[1] & 0xf) {
3285 case 0x4:
3286 /* Relative target port */
3287 rel_port = get_unaligned_be16(&d[6]);
3288 break;
3289 case 0x5:
3290 /* Target port group */
3291 group_id = get_unaligned_be16(&d[6]);
3292 break;
3293 default:
3294 break;
3295 }
3296 d += d[3] + 4;
3297 }
3298 rcu_read_unlock();
3299
3300 if (group_id >= 0 && rel_id && rel_port != -1)
3301 *rel_id = rel_port;
3302
3303 return group_id;
3304}
3305EXPORT_SYMBOL(scsi_vpd_tpg_id);
3306
3307/**
3308 * scsi_build_sense - build sense data for a command
3309 * @scmd: scsi command for which the sense should be formatted
3310 * @desc: Sense format (non-zero == descriptor format,
3311 * 0 == fixed format)
3312 * @key: Sense key
3313 * @asc: Additional sense code
3314 * @ascq: Additional sense code qualifier
3315 *
3316 **/
3317void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3318{
3319 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3320 scmd->result = SAM_STAT_CHECK_CONDITION;
3321}
3322EXPORT_SYMBOL_GPL(scsi_build_sense);