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1/*
2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
4 *
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
9 */
10
11#include <linux/bio.h>
12#include <linux/bitops.h>
13#include <linux/blkdev.h>
14#include <linux/completion.h>
15#include <linux/kernel.h>
16#include <linux/export.h>
17#include <linux/mempool.h>
18#include <linux/slab.h>
19#include <linux/init.h>
20#include <linux/pci.h>
21#include <linux/delay.h>
22#include <linux/hardirq.h>
23#include <linux/scatterlist.h>
24#include <linux/blk-mq.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_dh.h>
36
37#include <trace/events/scsi.h>
38
39#include "scsi_priv.h"
40#include "scsi_logging.h"
41
42
43#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
44#define SG_MEMPOOL_SIZE 2
45
46struct scsi_host_sg_pool {
47 size_t size;
48 char *name;
49 struct kmem_cache *slab;
50 mempool_t *pool;
51};
52
53#define SP(x) { .size = x, "sgpool-" __stringify(x) }
54#if (SCSI_MAX_SG_SEGMENTS < 32)
55#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
56#endif
57static struct scsi_host_sg_pool scsi_sg_pools[] = {
58 SP(8),
59 SP(16),
60#if (SCSI_MAX_SG_SEGMENTS > 32)
61 SP(32),
62#if (SCSI_MAX_SG_SEGMENTS > 64)
63 SP(64),
64#if (SCSI_MAX_SG_SEGMENTS > 128)
65 SP(128),
66#if (SCSI_MAX_SG_SEGMENTS > 256)
67#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
68#endif
69#endif
70#endif
71#endif
72 SP(SCSI_MAX_SG_SEGMENTS)
73};
74#undef SP
75
76struct kmem_cache *scsi_sdb_cache;
77
78/*
79 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
80 * not change behaviour from the previous unplug mechanism, experimentation
81 * may prove this needs changing.
82 */
83#define SCSI_QUEUE_DELAY 3
84
85static void
86scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
87{
88 struct Scsi_Host *host = cmd->device->host;
89 struct scsi_device *device = cmd->device;
90 struct scsi_target *starget = scsi_target(device);
91
92 /*
93 * Set the appropriate busy bit for the device/host.
94 *
95 * If the host/device isn't busy, assume that something actually
96 * completed, and that we should be able to queue a command now.
97 *
98 * Note that the prior mid-layer assumption that any host could
99 * always queue at least one command is now broken. The mid-layer
100 * will implement a user specifiable stall (see
101 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
102 * if a command is requeued with no other commands outstanding
103 * either for the device or for the host.
104 */
105 switch (reason) {
106 case SCSI_MLQUEUE_HOST_BUSY:
107 atomic_set(&host->host_blocked, host->max_host_blocked);
108 break;
109 case SCSI_MLQUEUE_DEVICE_BUSY:
110 case SCSI_MLQUEUE_EH_RETRY:
111 atomic_set(&device->device_blocked,
112 device->max_device_blocked);
113 break;
114 case SCSI_MLQUEUE_TARGET_BUSY:
115 atomic_set(&starget->target_blocked,
116 starget->max_target_blocked);
117 break;
118 }
119}
120
121static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
122{
123 struct scsi_device *sdev = cmd->device;
124 struct request_queue *q = cmd->request->q;
125
126 blk_mq_requeue_request(cmd->request);
127 blk_mq_kick_requeue_list(q);
128 put_device(&sdev->sdev_gendev);
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, int unbusy)
144{
145 struct scsi_device *device = cmd->device;
146 struct request_queue *q = device->request_queue;
147 unsigned long flags;
148
149 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
150 "Inserting command %p into mlqueue\n", cmd));
151
152 scsi_set_blocked(cmd, reason);
153
154 /*
155 * Decrement the counters, since these commands are no longer
156 * active on the host/device.
157 */
158 if (unbusy)
159 scsi_device_unbusy(device);
160
161 /*
162 * Requeue this command. It will go before all other commands
163 * that are already in the queue. Schedule requeue work under
164 * lock such that the kblockd_schedule_work() call happens
165 * before blk_cleanup_queue() finishes.
166 */
167 cmd->result = 0;
168 if (q->mq_ops) {
169 scsi_mq_requeue_cmd(cmd);
170 return;
171 }
172 spin_lock_irqsave(q->queue_lock, flags);
173 blk_requeue_request(q, cmd->request);
174 kblockd_schedule_work(&device->requeue_work);
175 spin_unlock_irqrestore(q->queue_lock, flags);
176}
177
178/*
179 * Function: scsi_queue_insert()
180 *
181 * Purpose: Insert a command in the midlevel queue.
182 *
183 * Arguments: cmd - command that we are adding to queue.
184 * reason - why we are inserting command to queue.
185 *
186 * Lock status: Assumed that lock is not held upon entry.
187 *
188 * Returns: Nothing.
189 *
190 * Notes: We do this for one of two cases. Either the host is busy
191 * and it cannot accept any more commands for the time being,
192 * or the device returned QUEUE_FULL and can accept no more
193 * commands.
194 * Notes: This could be called either from an interrupt context or a
195 * normal process context.
196 */
197void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
198{
199 __scsi_queue_insert(cmd, reason, 1);
200}
201/**
202 * scsi_execute - insert request and wait for the result
203 * @sdev: scsi device
204 * @cmd: scsi command
205 * @data_direction: data direction
206 * @buffer: data buffer
207 * @bufflen: len of buffer
208 * @sense: optional sense buffer
209 * @timeout: request timeout in seconds
210 * @retries: number of times to retry request
211 * @flags: or into request flags;
212 * @resid: optional residual length
213 *
214 * returns the req->errors value which is the scsi_cmnd result
215 * field.
216 */
217int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
218 int data_direction, void *buffer, unsigned bufflen,
219 unsigned char *sense, int timeout, int retries, u64 flags,
220 int *resid)
221{
222 struct request *req;
223 int write = (data_direction == DMA_TO_DEVICE);
224 int ret = DRIVER_ERROR << 24;
225
226 req = blk_get_request(sdev->request_queue, write, __GFP_RECLAIM);
227 if (IS_ERR(req))
228 return ret;
229 blk_rq_set_block_pc(req);
230
231 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
232 buffer, bufflen, __GFP_RECLAIM))
233 goto out;
234
235 req->cmd_len = COMMAND_SIZE(cmd[0]);
236 memcpy(req->cmd, cmd, req->cmd_len);
237 req->sense = sense;
238 req->sense_len = 0;
239 req->retries = retries;
240 req->timeout = timeout;
241 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
242
243 /*
244 * head injection *required* here otherwise quiesce won't work
245 */
246 blk_execute_rq(req->q, NULL, req, 1);
247
248 /*
249 * Some devices (USB mass-storage in particular) may transfer
250 * garbage data together with a residue indicating that the data
251 * is invalid. Prevent the garbage from being misinterpreted
252 * and prevent security leaks by zeroing out the excess data.
253 */
254 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
255 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
256
257 if (resid)
258 *resid = req->resid_len;
259 ret = req->errors;
260 out:
261 blk_put_request(req);
262
263 return ret;
264}
265EXPORT_SYMBOL(scsi_execute);
266
267int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
268 int data_direction, void *buffer, unsigned bufflen,
269 struct scsi_sense_hdr *sshdr, int timeout, int retries,
270 int *resid, u64 flags)
271{
272 char *sense = NULL;
273 int result;
274
275 if (sshdr) {
276 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
277 if (!sense)
278 return DRIVER_ERROR << 24;
279 }
280 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
281 sense, timeout, retries, flags, resid);
282 if (sshdr)
283 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
284
285 kfree(sense);
286 return result;
287}
288EXPORT_SYMBOL(scsi_execute_req_flags);
289
290/*
291 * Function: scsi_init_cmd_errh()
292 *
293 * Purpose: Initialize cmd fields related to error handling.
294 *
295 * Arguments: cmd - command that is ready to be queued.
296 *
297 * Notes: This function has the job of initializing a number of
298 * fields related to error handling. Typically this will
299 * be called once for each command, as required.
300 */
301static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
302{
303 cmd->serial_number = 0;
304 scsi_set_resid(cmd, 0);
305 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
306 if (cmd->cmd_len == 0)
307 cmd->cmd_len = scsi_command_size(cmd->cmnd);
308}
309
310void scsi_device_unbusy(struct scsi_device *sdev)
311{
312 struct Scsi_Host *shost = sdev->host;
313 struct scsi_target *starget = scsi_target(sdev);
314 unsigned long flags;
315
316 atomic_dec(&shost->host_busy);
317 if (starget->can_queue > 0)
318 atomic_dec(&starget->target_busy);
319
320 if (unlikely(scsi_host_in_recovery(shost) &&
321 (shost->host_failed || shost->host_eh_scheduled))) {
322 spin_lock_irqsave(shost->host_lock, flags);
323 scsi_eh_wakeup(shost);
324 spin_unlock_irqrestore(shost->host_lock, flags);
325 }
326
327 atomic_dec(&sdev->device_busy);
328}
329
330static void scsi_kick_queue(struct request_queue *q)
331{
332 if (q->mq_ops)
333 blk_mq_start_hw_queues(q);
334 else
335 blk_run_queue(q);
336}
337
338/*
339 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
340 * and call blk_run_queue for all the scsi_devices on the target -
341 * including current_sdev first.
342 *
343 * Called with *no* scsi locks held.
344 */
345static void scsi_single_lun_run(struct scsi_device *current_sdev)
346{
347 struct Scsi_Host *shost = current_sdev->host;
348 struct scsi_device *sdev, *tmp;
349 struct scsi_target *starget = scsi_target(current_sdev);
350 unsigned long flags;
351
352 spin_lock_irqsave(shost->host_lock, flags);
353 starget->starget_sdev_user = NULL;
354 spin_unlock_irqrestore(shost->host_lock, flags);
355
356 /*
357 * Call blk_run_queue for all LUNs on the target, starting with
358 * current_sdev. We race with others (to set starget_sdev_user),
359 * but in most cases, we will be first. Ideally, each LU on the
360 * target would get some limited time or requests on the target.
361 */
362 scsi_kick_queue(current_sdev->request_queue);
363
364 spin_lock_irqsave(shost->host_lock, flags);
365 if (starget->starget_sdev_user)
366 goto out;
367 list_for_each_entry_safe(sdev, tmp, &starget->devices,
368 same_target_siblings) {
369 if (sdev == current_sdev)
370 continue;
371 if (scsi_device_get(sdev))
372 continue;
373
374 spin_unlock_irqrestore(shost->host_lock, flags);
375 scsi_kick_queue(sdev->request_queue);
376 spin_lock_irqsave(shost->host_lock, flags);
377
378 scsi_device_put(sdev);
379 }
380 out:
381 spin_unlock_irqrestore(shost->host_lock, flags);
382}
383
384static inline bool scsi_device_is_busy(struct scsi_device *sdev)
385{
386 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
387 return true;
388 if (atomic_read(&sdev->device_blocked) > 0)
389 return true;
390 return false;
391}
392
393static inline bool scsi_target_is_busy(struct scsi_target *starget)
394{
395 if (starget->can_queue > 0) {
396 if (atomic_read(&starget->target_busy) >= starget->can_queue)
397 return true;
398 if (atomic_read(&starget->target_blocked) > 0)
399 return true;
400 }
401 return false;
402}
403
404static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
405{
406 if (shost->can_queue > 0 &&
407 atomic_read(&shost->host_busy) >= shost->can_queue)
408 return true;
409 if (atomic_read(&shost->host_blocked) > 0)
410 return true;
411 if (shost->host_self_blocked)
412 return true;
413 return false;
414}
415
416static void scsi_starved_list_run(struct Scsi_Host *shost)
417{
418 LIST_HEAD(starved_list);
419 struct scsi_device *sdev;
420 unsigned long flags;
421
422 spin_lock_irqsave(shost->host_lock, flags);
423 list_splice_init(&shost->starved_list, &starved_list);
424
425 while (!list_empty(&starved_list)) {
426 struct request_queue *slq;
427
428 /*
429 * As long as shost is accepting commands and we have
430 * starved queues, call blk_run_queue. scsi_request_fn
431 * drops the queue_lock and can add us back to the
432 * starved_list.
433 *
434 * host_lock protects the starved_list and starved_entry.
435 * scsi_request_fn must get the host_lock before checking
436 * or modifying starved_list or starved_entry.
437 */
438 if (scsi_host_is_busy(shost))
439 break;
440
441 sdev = list_entry(starved_list.next,
442 struct scsi_device, starved_entry);
443 list_del_init(&sdev->starved_entry);
444 if (scsi_target_is_busy(scsi_target(sdev))) {
445 list_move_tail(&sdev->starved_entry,
446 &shost->starved_list);
447 continue;
448 }
449
450 /*
451 * Once we drop the host lock, a racing scsi_remove_device()
452 * call may remove the sdev from the starved list and destroy
453 * it and the queue. Mitigate by taking a reference to the
454 * queue and never touching the sdev again after we drop the
455 * host lock. Note: if __scsi_remove_device() invokes
456 * blk_cleanup_queue() before the queue is run from this
457 * function then blk_run_queue() will return immediately since
458 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
459 */
460 slq = sdev->request_queue;
461 if (!blk_get_queue(slq))
462 continue;
463 spin_unlock_irqrestore(shost->host_lock, flags);
464
465 scsi_kick_queue(slq);
466 blk_put_queue(slq);
467
468 spin_lock_irqsave(shost->host_lock, flags);
469 }
470 /* put any unprocessed entries back */
471 list_splice(&starved_list, &shost->starved_list);
472 spin_unlock_irqrestore(shost->host_lock, flags);
473}
474
475/*
476 * Function: scsi_run_queue()
477 *
478 * Purpose: Select a proper request queue to serve next
479 *
480 * Arguments: q - last request's queue
481 *
482 * Returns: Nothing
483 *
484 * Notes: The previous command was completely finished, start
485 * a new one if possible.
486 */
487static void scsi_run_queue(struct request_queue *q)
488{
489 struct scsi_device *sdev = q->queuedata;
490
491 if (scsi_target(sdev)->single_lun)
492 scsi_single_lun_run(sdev);
493 if (!list_empty(&sdev->host->starved_list))
494 scsi_starved_list_run(sdev->host);
495
496 if (q->mq_ops)
497 blk_mq_start_stopped_hw_queues(q, false);
498 else
499 blk_run_queue(q);
500}
501
502void scsi_requeue_run_queue(struct work_struct *work)
503{
504 struct scsi_device *sdev;
505 struct request_queue *q;
506
507 sdev = container_of(work, struct scsi_device, requeue_work);
508 q = sdev->request_queue;
509 scsi_run_queue(q);
510}
511
512/*
513 * Function: scsi_requeue_command()
514 *
515 * Purpose: Handle post-processing of completed commands.
516 *
517 * Arguments: q - queue to operate on
518 * cmd - command that may need to be requeued.
519 *
520 * Returns: Nothing
521 *
522 * Notes: After command completion, there may be blocks left
523 * over which weren't finished by the previous command
524 * this can be for a number of reasons - the main one is
525 * I/O errors in the middle of the request, in which case
526 * we need to request the blocks that come after the bad
527 * sector.
528 * Notes: Upon return, cmd is a stale pointer.
529 */
530static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
531{
532 struct scsi_device *sdev = cmd->device;
533 struct request *req = cmd->request;
534 unsigned long flags;
535
536 spin_lock_irqsave(q->queue_lock, flags);
537 blk_unprep_request(req);
538 req->special = NULL;
539 scsi_put_command(cmd);
540 blk_requeue_request(q, req);
541 spin_unlock_irqrestore(q->queue_lock, flags);
542
543 scsi_run_queue(q);
544
545 put_device(&sdev->sdev_gendev);
546}
547
548void scsi_run_host_queues(struct Scsi_Host *shost)
549{
550 struct scsi_device *sdev;
551
552 shost_for_each_device(sdev, shost)
553 scsi_run_queue(sdev->request_queue);
554}
555
556static inline unsigned int scsi_sgtable_index(unsigned short nents)
557{
558 unsigned int index;
559
560 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
561
562 if (nents <= 8)
563 index = 0;
564 else
565 index = get_count_order(nents) - 3;
566
567 return index;
568}
569
570static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
571{
572 struct scsi_host_sg_pool *sgp;
573
574 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
575 mempool_free(sgl, sgp->pool);
576}
577
578static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
579{
580 struct scsi_host_sg_pool *sgp;
581
582 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
583 return mempool_alloc(sgp->pool, gfp_mask);
584}
585
586static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
587{
588 if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
589 return;
590 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
591}
592
593static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
594{
595 struct scatterlist *first_chunk = NULL;
596 int ret;
597
598 BUG_ON(!nents);
599
600 if (mq) {
601 if (nents <= SCSI_MAX_SG_SEGMENTS) {
602 sdb->table.nents = sdb->table.orig_nents = nents;
603 sg_init_table(sdb->table.sgl, nents);
604 return 0;
605 }
606 first_chunk = sdb->table.sgl;
607 }
608
609 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
610 first_chunk, GFP_ATOMIC, scsi_sg_alloc);
611 if (unlikely(ret))
612 scsi_free_sgtable(sdb, mq);
613 return ret;
614}
615
616static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
617{
618 if (cmd->request->cmd_type == REQ_TYPE_FS) {
619 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
620
621 if (drv->uninit_command)
622 drv->uninit_command(cmd);
623 }
624}
625
626static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
627{
628 if (cmd->sdb.table.nents)
629 scsi_free_sgtable(&cmd->sdb, true);
630 if (cmd->request->next_rq && cmd->request->next_rq->special)
631 scsi_free_sgtable(cmd->request->next_rq->special, true);
632 if (scsi_prot_sg_count(cmd))
633 scsi_free_sgtable(cmd->prot_sdb, true);
634}
635
636static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
637{
638 struct scsi_device *sdev = cmd->device;
639 struct Scsi_Host *shost = sdev->host;
640 unsigned long flags;
641
642 scsi_mq_free_sgtables(cmd);
643 scsi_uninit_cmd(cmd);
644
645 if (shost->use_cmd_list) {
646 BUG_ON(list_empty(&cmd->list));
647 spin_lock_irqsave(&sdev->list_lock, flags);
648 list_del_init(&cmd->list);
649 spin_unlock_irqrestore(&sdev->list_lock, flags);
650 }
651}
652
653/*
654 * Function: scsi_release_buffers()
655 *
656 * Purpose: Free resources allocate for a scsi_command.
657 *
658 * Arguments: cmd - command that we are bailing.
659 *
660 * Lock status: Assumed that no lock is held upon entry.
661 *
662 * Returns: Nothing
663 *
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
667 * the scatter-gather table.
668 */
669static void scsi_release_buffers(struct scsi_cmnd *cmd)
670{
671 if (cmd->sdb.table.nents)
672 scsi_free_sgtable(&cmd->sdb, false);
673
674 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
675
676 if (scsi_prot_sg_count(cmd))
677 scsi_free_sgtable(cmd->prot_sdb, false);
678}
679
680static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
681{
682 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
683
684 scsi_free_sgtable(bidi_sdb, false);
685 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
686 cmd->request->next_rq->special = NULL;
687}
688
689static bool scsi_end_request(struct request *req, int error,
690 unsigned int bytes, unsigned int bidi_bytes)
691{
692 struct scsi_cmnd *cmd = req->special;
693 struct scsi_device *sdev = cmd->device;
694 struct request_queue *q = sdev->request_queue;
695
696 if (blk_update_request(req, error, bytes))
697 return true;
698
699 /* Bidi request must be completed as a whole */
700 if (unlikely(bidi_bytes) &&
701 blk_update_request(req->next_rq, error, bidi_bytes))
702 return true;
703
704 if (blk_queue_add_random(q))
705 add_disk_randomness(req->rq_disk);
706
707 if (req->mq_ctx) {
708 /*
709 * In the MQ case the command gets freed by __blk_mq_end_request,
710 * so we have to do all cleanup that depends on it earlier.
711 *
712 * We also can't kick the queues from irq context, so we
713 * will have to defer it to a workqueue.
714 */
715 scsi_mq_uninit_cmd(cmd);
716
717 __blk_mq_end_request(req, error);
718
719 if (scsi_target(sdev)->single_lun ||
720 !list_empty(&sdev->host->starved_list))
721 kblockd_schedule_work(&sdev->requeue_work);
722 else
723 blk_mq_start_stopped_hw_queues(q, true);
724 } else {
725 unsigned long flags;
726
727 if (bidi_bytes)
728 scsi_release_bidi_buffers(cmd);
729
730 spin_lock_irqsave(q->queue_lock, flags);
731 blk_finish_request(req, error);
732 spin_unlock_irqrestore(q->queue_lock, flags);
733
734 scsi_release_buffers(cmd);
735
736 scsi_put_command(cmd);
737 scsi_run_queue(q);
738 }
739
740 put_device(&sdev->sdev_gendev);
741 return false;
742}
743
744/**
745 * __scsi_error_from_host_byte - translate SCSI error code into errno
746 * @cmd: SCSI command (unused)
747 * @result: scsi error code
748 *
749 * Translate SCSI error code into standard UNIX errno.
750 * Return values:
751 * -ENOLINK temporary transport failure
752 * -EREMOTEIO permanent target failure, do not retry
753 * -EBADE permanent nexus failure, retry on other path
754 * -ENOSPC No write space available
755 * -ENODATA Medium error
756 * -EIO unspecified I/O error
757 */
758static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
759{
760 int error = 0;
761
762 switch(host_byte(result)) {
763 case DID_TRANSPORT_FAILFAST:
764 error = -ENOLINK;
765 break;
766 case DID_TARGET_FAILURE:
767 set_host_byte(cmd, DID_OK);
768 error = -EREMOTEIO;
769 break;
770 case DID_NEXUS_FAILURE:
771 set_host_byte(cmd, DID_OK);
772 error = -EBADE;
773 break;
774 case DID_ALLOC_FAILURE:
775 set_host_byte(cmd, DID_OK);
776 error = -ENOSPC;
777 break;
778 case DID_MEDIUM_ERROR:
779 set_host_byte(cmd, DID_OK);
780 error = -ENODATA;
781 break;
782 default:
783 error = -EIO;
784 break;
785 }
786
787 return error;
788}
789
790/*
791 * Function: scsi_io_completion()
792 *
793 * Purpose: Completion processing for block device I/O requests.
794 *
795 * Arguments: cmd - command that is finished.
796 *
797 * Lock status: Assumed that no lock is held upon entry.
798 *
799 * Returns: Nothing
800 *
801 * Notes: We will finish off the specified number of sectors. If we
802 * are done, the command block will be released and the queue
803 * function will be goosed. If we are not done then we have to
804 * figure out what to do next:
805 *
806 * a) We can call scsi_requeue_command(). The request
807 * will be unprepared and put back on the queue. Then
808 * a new command will be created for it. This should
809 * be used if we made forward progress, or if we want
810 * to switch from READ(10) to READ(6) for example.
811 *
812 * b) We can call __scsi_queue_insert(). The request will
813 * be put back on the queue and retried using the same
814 * command as before, possibly after a delay.
815 *
816 * c) We can call scsi_end_request() with -EIO to fail
817 * the remainder of the request.
818 */
819void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
820{
821 int result = cmd->result;
822 struct request_queue *q = cmd->device->request_queue;
823 struct request *req = cmd->request;
824 int error = 0;
825 struct scsi_sense_hdr sshdr;
826 bool sense_valid = false;
827 int sense_deferred = 0, level = 0;
828 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
829 ACTION_DELAYED_RETRY} action;
830 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
831
832 if (result) {
833 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
834 if (sense_valid)
835 sense_deferred = scsi_sense_is_deferred(&sshdr);
836 }
837
838 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
839 if (result) {
840 if (sense_valid && req->sense) {
841 /*
842 * SG_IO wants current and deferred errors
843 */
844 int len = 8 + cmd->sense_buffer[7];
845
846 if (len > SCSI_SENSE_BUFFERSIZE)
847 len = SCSI_SENSE_BUFFERSIZE;
848 memcpy(req->sense, cmd->sense_buffer, len);
849 req->sense_len = len;
850 }
851 if (!sense_deferred)
852 error = __scsi_error_from_host_byte(cmd, result);
853 }
854 /*
855 * __scsi_error_from_host_byte may have reset the host_byte
856 */
857 req->errors = cmd->result;
858
859 req->resid_len = scsi_get_resid(cmd);
860
861 if (scsi_bidi_cmnd(cmd)) {
862 /*
863 * Bidi commands Must be complete as a whole,
864 * both sides at once.
865 */
866 req->next_rq->resid_len = scsi_in(cmd)->resid;
867 if (scsi_end_request(req, 0, blk_rq_bytes(req),
868 blk_rq_bytes(req->next_rq)))
869 BUG();
870 return;
871 }
872 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
873 /*
874 * Certain non BLOCK_PC requests are commands that don't
875 * actually transfer anything (FLUSH), so cannot use
876 * good_bytes != blk_rq_bytes(req) as the signal for an error.
877 * This sets the error explicitly for the problem case.
878 */
879 error = __scsi_error_from_host_byte(cmd, result);
880 }
881
882 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
883 BUG_ON(blk_bidi_rq(req));
884
885 /*
886 * Next deal with any sectors which we were able to correctly
887 * handle.
888 */
889 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
890 "%u sectors total, %d bytes done.\n",
891 blk_rq_sectors(req), good_bytes));
892
893 /*
894 * Recovered errors need reporting, but they're always treated
895 * as success, so fiddle the result code here. For BLOCK_PC
896 * we already took a copy of the original into rq->errors which
897 * is what gets returned to the user
898 */
899 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
900 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
901 * print since caller wants ATA registers. Only occurs on
902 * SCSI ATA PASS_THROUGH commands when CK_COND=1
903 */
904 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
905 ;
906 else if (!(req->cmd_flags & REQ_QUIET))
907 scsi_print_sense(cmd);
908 result = 0;
909 /* BLOCK_PC may have set error */
910 error = 0;
911 }
912
913 /*
914 * If we finished all bytes in the request we are done now.
915 */
916 if (!scsi_end_request(req, error, good_bytes, 0))
917 return;
918
919 /*
920 * Kill remainder if no retrys.
921 */
922 if (error && scsi_noretry_cmd(cmd)) {
923 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
924 BUG();
925 return;
926 }
927
928 /*
929 * If there had been no error, but we have leftover bytes in the
930 * requeues just queue the command up again.
931 */
932 if (result == 0)
933 goto requeue;
934
935 error = __scsi_error_from_host_byte(cmd, result);
936
937 if (host_byte(result) == DID_RESET) {
938 /* Third party bus reset or reset for error recovery
939 * reasons. Just retry the command and see what
940 * happens.
941 */
942 action = ACTION_RETRY;
943 } else if (sense_valid && !sense_deferred) {
944 switch (sshdr.sense_key) {
945 case UNIT_ATTENTION:
946 if (cmd->device->removable) {
947 /* Detected disc change. Set a bit
948 * and quietly refuse further access.
949 */
950 cmd->device->changed = 1;
951 action = ACTION_FAIL;
952 } else {
953 /* Must have been a power glitch, or a
954 * bus reset. Could not have been a
955 * media change, so we just retry the
956 * command and see what happens.
957 */
958 action = ACTION_RETRY;
959 }
960 break;
961 case ILLEGAL_REQUEST:
962 /* If we had an ILLEGAL REQUEST returned, then
963 * we may have performed an unsupported
964 * command. The only thing this should be
965 * would be a ten byte read where only a six
966 * byte read was supported. Also, on a system
967 * where READ CAPACITY failed, we may have
968 * read past the end of the disk.
969 */
970 if ((cmd->device->use_10_for_rw &&
971 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
972 (cmd->cmnd[0] == READ_10 ||
973 cmd->cmnd[0] == WRITE_10)) {
974 /* This will issue a new 6-byte command. */
975 cmd->device->use_10_for_rw = 0;
976 action = ACTION_REPREP;
977 } else if (sshdr.asc == 0x10) /* DIX */ {
978 action = ACTION_FAIL;
979 error = -EILSEQ;
980 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
981 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
982 action = ACTION_FAIL;
983 error = -EREMOTEIO;
984 } else
985 action = ACTION_FAIL;
986 break;
987 case ABORTED_COMMAND:
988 action = ACTION_FAIL;
989 if (sshdr.asc == 0x10) /* DIF */
990 error = -EILSEQ;
991 break;
992 case NOT_READY:
993 /* If the device is in the process of becoming
994 * ready, or has a temporary blockage, retry.
995 */
996 if (sshdr.asc == 0x04) {
997 switch (sshdr.ascq) {
998 case 0x01: /* becoming ready */
999 case 0x04: /* format in progress */
1000 case 0x05: /* rebuild in progress */
1001 case 0x06: /* recalculation in progress */
1002 case 0x07: /* operation in progress */
1003 case 0x08: /* Long write in progress */
1004 case 0x09: /* self test in progress */
1005 case 0x14: /* space allocation in progress */
1006 action = ACTION_DELAYED_RETRY;
1007 break;
1008 default:
1009 action = ACTION_FAIL;
1010 break;
1011 }
1012 } else
1013 action = ACTION_FAIL;
1014 break;
1015 case VOLUME_OVERFLOW:
1016 /* See SSC3rXX or current. */
1017 action = ACTION_FAIL;
1018 break;
1019 default:
1020 action = ACTION_FAIL;
1021 break;
1022 }
1023 } else
1024 action = ACTION_FAIL;
1025
1026 if (action != ACTION_FAIL &&
1027 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
1028 action = ACTION_FAIL;
1029
1030 switch (action) {
1031 case ACTION_FAIL:
1032 /* Give up and fail the remainder of the request */
1033 if (!(req->cmd_flags & REQ_QUIET)) {
1034 static DEFINE_RATELIMIT_STATE(_rs,
1035 DEFAULT_RATELIMIT_INTERVAL,
1036 DEFAULT_RATELIMIT_BURST);
1037
1038 if (unlikely(scsi_logging_level))
1039 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
1040 SCSI_LOG_MLCOMPLETE_BITS);
1041
1042 /*
1043 * if logging is enabled the failure will be printed
1044 * in scsi_log_completion(), so avoid duplicate messages
1045 */
1046 if (!level && __ratelimit(&_rs)) {
1047 scsi_print_result(cmd, NULL, FAILED);
1048 if (driver_byte(result) & DRIVER_SENSE)
1049 scsi_print_sense(cmd);
1050 scsi_print_command(cmd);
1051 }
1052 }
1053 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1054 return;
1055 /*FALLTHRU*/
1056 case ACTION_REPREP:
1057 requeue:
1058 /* Unprep the request and put it back at the head of the queue.
1059 * A new command will be prepared and issued.
1060 */
1061 if (q->mq_ops) {
1062 cmd->request->cmd_flags &= ~REQ_DONTPREP;
1063 scsi_mq_uninit_cmd(cmd);
1064 scsi_mq_requeue_cmd(cmd);
1065 } else {
1066 scsi_release_buffers(cmd);
1067 scsi_requeue_command(q, cmd);
1068 }
1069 break;
1070 case ACTION_RETRY:
1071 /* Retry the same command immediately */
1072 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1073 break;
1074 case ACTION_DELAYED_RETRY:
1075 /* Retry the same command after a delay */
1076 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1077 break;
1078 }
1079}
1080
1081static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
1082{
1083 int count;
1084
1085 /*
1086 * If sg table allocation fails, requeue request later.
1087 */
1088 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1089 req->mq_ctx != NULL)))
1090 return BLKPREP_DEFER;
1091
1092 /*
1093 * Next, walk the list, and fill in the addresses and sizes of
1094 * each segment.
1095 */
1096 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1097 BUG_ON(count > sdb->table.nents);
1098 sdb->table.nents = count;
1099 sdb->length = blk_rq_bytes(req);
1100 return BLKPREP_OK;
1101}
1102
1103/*
1104 * Function: scsi_init_io()
1105 *
1106 * Purpose: SCSI I/O initialize function.
1107 *
1108 * Arguments: cmd - Command descriptor we wish to initialize
1109 *
1110 * Returns: 0 on success
1111 * BLKPREP_DEFER if the failure is retryable
1112 * BLKPREP_KILL if the failure is fatal
1113 */
1114int scsi_init_io(struct scsi_cmnd *cmd)
1115{
1116 struct scsi_device *sdev = cmd->device;
1117 struct request *rq = cmd->request;
1118 bool is_mq = (rq->mq_ctx != NULL);
1119 int error;
1120
1121 BUG_ON(!rq->nr_phys_segments);
1122
1123 error = scsi_init_sgtable(rq, &cmd->sdb);
1124 if (error)
1125 goto err_exit;
1126
1127 if (blk_bidi_rq(rq)) {
1128 if (!rq->q->mq_ops) {
1129 struct scsi_data_buffer *bidi_sdb =
1130 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1131 if (!bidi_sdb) {
1132 error = BLKPREP_DEFER;
1133 goto err_exit;
1134 }
1135
1136 rq->next_rq->special = bidi_sdb;
1137 }
1138
1139 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1140 if (error)
1141 goto err_exit;
1142 }
1143
1144 if (blk_integrity_rq(rq)) {
1145 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1146 int ivecs, count;
1147
1148 if (prot_sdb == NULL) {
1149 /*
1150 * This can happen if someone (e.g. multipath)
1151 * queues a command to a device on an adapter
1152 * that does not support DIX.
1153 */
1154 WARN_ON_ONCE(1);
1155 error = BLKPREP_KILL;
1156 goto err_exit;
1157 }
1158
1159 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1160
1161 if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
1162 error = BLKPREP_DEFER;
1163 goto err_exit;
1164 }
1165
1166 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1167 prot_sdb->table.sgl);
1168 BUG_ON(unlikely(count > ivecs));
1169 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1170
1171 cmd->prot_sdb = prot_sdb;
1172 cmd->prot_sdb->table.nents = count;
1173 }
1174
1175 return BLKPREP_OK;
1176err_exit:
1177 if (is_mq) {
1178 scsi_mq_free_sgtables(cmd);
1179 } else {
1180 scsi_release_buffers(cmd);
1181 cmd->request->special = NULL;
1182 scsi_put_command(cmd);
1183 put_device(&sdev->sdev_gendev);
1184 }
1185 return error;
1186}
1187EXPORT_SYMBOL(scsi_init_io);
1188
1189static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1190 struct request *req)
1191{
1192 struct scsi_cmnd *cmd;
1193
1194 if (!req->special) {
1195 /* Bail if we can't get a reference to the device */
1196 if (!get_device(&sdev->sdev_gendev))
1197 return NULL;
1198
1199 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1200 if (unlikely(!cmd)) {
1201 put_device(&sdev->sdev_gendev);
1202 return NULL;
1203 }
1204 req->special = cmd;
1205 } else {
1206 cmd = req->special;
1207 }
1208
1209 /* pull a tag out of the request if we have one */
1210 cmd->tag = req->tag;
1211 cmd->request = req;
1212
1213 cmd->cmnd = req->cmd;
1214 cmd->prot_op = SCSI_PROT_NORMAL;
1215
1216 return cmd;
1217}
1218
1219static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1220{
1221 struct scsi_cmnd *cmd = req->special;
1222
1223 /*
1224 * BLOCK_PC requests may transfer data, in which case they must
1225 * a bio attached to them. Or they might contain a SCSI command
1226 * that does not transfer data, in which case they may optionally
1227 * submit a request without an attached bio.
1228 */
1229 if (req->bio) {
1230 int ret = scsi_init_io(cmd);
1231 if (unlikely(ret))
1232 return ret;
1233 } else {
1234 BUG_ON(blk_rq_bytes(req));
1235
1236 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1237 }
1238
1239 cmd->cmd_len = req->cmd_len;
1240 cmd->transfersize = blk_rq_bytes(req);
1241 cmd->allowed = req->retries;
1242 return BLKPREP_OK;
1243}
1244
1245/*
1246 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1247 * that still need to be translated to SCSI CDBs from the ULD.
1248 */
1249static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1250{
1251 struct scsi_cmnd *cmd = req->special;
1252
1253 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1254 int ret = sdev->handler->prep_fn(sdev, req);
1255 if (ret != BLKPREP_OK)
1256 return ret;
1257 }
1258
1259 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1260 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1261}
1262
1263static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1264{
1265 struct scsi_cmnd *cmd = req->special;
1266
1267 if (!blk_rq_bytes(req))
1268 cmd->sc_data_direction = DMA_NONE;
1269 else if (rq_data_dir(req) == WRITE)
1270 cmd->sc_data_direction = DMA_TO_DEVICE;
1271 else
1272 cmd->sc_data_direction = DMA_FROM_DEVICE;
1273
1274 switch (req->cmd_type) {
1275 case REQ_TYPE_FS:
1276 return scsi_setup_fs_cmnd(sdev, req);
1277 case REQ_TYPE_BLOCK_PC:
1278 return scsi_setup_blk_pc_cmnd(sdev, req);
1279 default:
1280 return BLKPREP_KILL;
1281 }
1282}
1283
1284static int
1285scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1286{
1287 int ret = BLKPREP_OK;
1288
1289 /*
1290 * If the device is not in running state we will reject some
1291 * or all commands.
1292 */
1293 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1294 switch (sdev->sdev_state) {
1295 case SDEV_OFFLINE:
1296 case SDEV_TRANSPORT_OFFLINE:
1297 /*
1298 * If the device is offline we refuse to process any
1299 * commands. The device must be brought online
1300 * before trying any recovery commands.
1301 */
1302 sdev_printk(KERN_ERR, sdev,
1303 "rejecting I/O to offline device\n");
1304 ret = BLKPREP_KILL;
1305 break;
1306 case SDEV_DEL:
1307 /*
1308 * If the device is fully deleted, we refuse to
1309 * process any commands as well.
1310 */
1311 sdev_printk(KERN_ERR, sdev,
1312 "rejecting I/O to dead device\n");
1313 ret = BLKPREP_KILL;
1314 break;
1315 case SDEV_BLOCK:
1316 case SDEV_CREATED_BLOCK:
1317 ret = BLKPREP_DEFER;
1318 break;
1319 case SDEV_QUIESCE:
1320 /*
1321 * If the devices is blocked we defer normal commands.
1322 */
1323 if (!(req->cmd_flags & REQ_PREEMPT))
1324 ret = BLKPREP_DEFER;
1325 break;
1326 default:
1327 /*
1328 * For any other not fully online state we only allow
1329 * special commands. In particular any user initiated
1330 * command is not allowed.
1331 */
1332 if (!(req->cmd_flags & REQ_PREEMPT))
1333 ret = BLKPREP_KILL;
1334 break;
1335 }
1336 }
1337 return ret;
1338}
1339
1340static int
1341scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1342{
1343 struct scsi_device *sdev = q->queuedata;
1344
1345 switch (ret) {
1346 case BLKPREP_KILL:
1347 case BLKPREP_INVALID:
1348 req->errors = DID_NO_CONNECT << 16;
1349 /* release the command and kill it */
1350 if (req->special) {
1351 struct scsi_cmnd *cmd = req->special;
1352 scsi_release_buffers(cmd);
1353 scsi_put_command(cmd);
1354 put_device(&sdev->sdev_gendev);
1355 req->special = NULL;
1356 }
1357 break;
1358 case BLKPREP_DEFER:
1359 /*
1360 * If we defer, the blk_peek_request() returns NULL, but the
1361 * queue must be restarted, so we schedule a callback to happen
1362 * shortly.
1363 */
1364 if (atomic_read(&sdev->device_busy) == 0)
1365 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1366 break;
1367 default:
1368 req->cmd_flags |= REQ_DONTPREP;
1369 }
1370
1371 return ret;
1372}
1373
1374static int scsi_prep_fn(struct request_queue *q, struct request *req)
1375{
1376 struct scsi_device *sdev = q->queuedata;
1377 struct scsi_cmnd *cmd;
1378 int ret;
1379
1380 ret = scsi_prep_state_check(sdev, req);
1381 if (ret != BLKPREP_OK)
1382 goto out;
1383
1384 cmd = scsi_get_cmd_from_req(sdev, req);
1385 if (unlikely(!cmd)) {
1386 ret = BLKPREP_DEFER;
1387 goto out;
1388 }
1389
1390 ret = scsi_setup_cmnd(sdev, req);
1391out:
1392 return scsi_prep_return(q, req, ret);
1393}
1394
1395static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1396{
1397 scsi_uninit_cmd(req->special);
1398}
1399
1400/*
1401 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1402 * return 0.
1403 *
1404 * Called with the queue_lock held.
1405 */
1406static inline int scsi_dev_queue_ready(struct request_queue *q,
1407 struct scsi_device *sdev)
1408{
1409 unsigned int busy;
1410
1411 busy = atomic_inc_return(&sdev->device_busy) - 1;
1412 if (atomic_read(&sdev->device_blocked)) {
1413 if (busy)
1414 goto out_dec;
1415
1416 /*
1417 * unblock after device_blocked iterates to zero
1418 */
1419 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1420 /*
1421 * For the MQ case we take care of this in the caller.
1422 */
1423 if (!q->mq_ops)
1424 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1425 goto out_dec;
1426 }
1427 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1428 "unblocking device at zero depth\n"));
1429 }
1430
1431 if (busy >= sdev->queue_depth)
1432 goto out_dec;
1433
1434 return 1;
1435out_dec:
1436 atomic_dec(&sdev->device_busy);
1437 return 0;
1438}
1439
1440/*
1441 * scsi_target_queue_ready: checks if there we can send commands to target
1442 * @sdev: scsi device on starget to check.
1443 */
1444static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1445 struct scsi_device *sdev)
1446{
1447 struct scsi_target *starget = scsi_target(sdev);
1448 unsigned int busy;
1449
1450 if (starget->single_lun) {
1451 spin_lock_irq(shost->host_lock);
1452 if (starget->starget_sdev_user &&
1453 starget->starget_sdev_user != sdev) {
1454 spin_unlock_irq(shost->host_lock);
1455 return 0;
1456 }
1457 starget->starget_sdev_user = sdev;
1458 spin_unlock_irq(shost->host_lock);
1459 }
1460
1461 if (starget->can_queue <= 0)
1462 return 1;
1463
1464 busy = atomic_inc_return(&starget->target_busy) - 1;
1465 if (atomic_read(&starget->target_blocked) > 0) {
1466 if (busy)
1467 goto starved;
1468
1469 /*
1470 * unblock after target_blocked iterates to zero
1471 */
1472 if (atomic_dec_return(&starget->target_blocked) > 0)
1473 goto out_dec;
1474
1475 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1476 "unblocking target at zero depth\n"));
1477 }
1478
1479 if (busy >= starget->can_queue)
1480 goto starved;
1481
1482 return 1;
1483
1484starved:
1485 spin_lock_irq(shost->host_lock);
1486 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1487 spin_unlock_irq(shost->host_lock);
1488out_dec:
1489 if (starget->can_queue > 0)
1490 atomic_dec(&starget->target_busy);
1491 return 0;
1492}
1493
1494/*
1495 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1496 * return 0. We must end up running the queue again whenever 0 is
1497 * returned, else IO can hang.
1498 */
1499static inline int scsi_host_queue_ready(struct request_queue *q,
1500 struct Scsi_Host *shost,
1501 struct scsi_device *sdev)
1502{
1503 unsigned int busy;
1504
1505 if (scsi_host_in_recovery(shost))
1506 return 0;
1507
1508 busy = atomic_inc_return(&shost->host_busy) - 1;
1509 if (atomic_read(&shost->host_blocked) > 0) {
1510 if (busy)
1511 goto starved;
1512
1513 /*
1514 * unblock after host_blocked iterates to zero
1515 */
1516 if (atomic_dec_return(&shost->host_blocked) > 0)
1517 goto out_dec;
1518
1519 SCSI_LOG_MLQUEUE(3,
1520 shost_printk(KERN_INFO, shost,
1521 "unblocking host at zero depth\n"));
1522 }
1523
1524 if (shost->can_queue > 0 && busy >= shost->can_queue)
1525 goto starved;
1526 if (shost->host_self_blocked)
1527 goto starved;
1528
1529 /* We're OK to process the command, so we can't be starved */
1530 if (!list_empty(&sdev->starved_entry)) {
1531 spin_lock_irq(shost->host_lock);
1532 if (!list_empty(&sdev->starved_entry))
1533 list_del_init(&sdev->starved_entry);
1534 spin_unlock_irq(shost->host_lock);
1535 }
1536
1537 return 1;
1538
1539starved:
1540 spin_lock_irq(shost->host_lock);
1541 if (list_empty(&sdev->starved_entry))
1542 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1543 spin_unlock_irq(shost->host_lock);
1544out_dec:
1545 atomic_dec(&shost->host_busy);
1546 return 0;
1547}
1548
1549/*
1550 * Busy state exporting function for request stacking drivers.
1551 *
1552 * For efficiency, no lock is taken to check the busy state of
1553 * shost/starget/sdev, since the returned value is not guaranteed and
1554 * may be changed after request stacking drivers call the function,
1555 * regardless of taking lock or not.
1556 *
1557 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1558 * needs to return 'not busy'. Otherwise, request stacking drivers
1559 * may hold requests forever.
1560 */
1561static int scsi_lld_busy(struct request_queue *q)
1562{
1563 struct scsi_device *sdev = q->queuedata;
1564 struct Scsi_Host *shost;
1565
1566 if (blk_queue_dying(q))
1567 return 0;
1568
1569 shost = sdev->host;
1570
1571 /*
1572 * Ignore host/starget busy state.
1573 * Since block layer does not have a concept of fairness across
1574 * multiple queues, congestion of host/starget needs to be handled
1575 * in SCSI layer.
1576 */
1577 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1578 return 1;
1579
1580 return 0;
1581}
1582
1583/*
1584 * Kill a request for a dead device
1585 */
1586static void scsi_kill_request(struct request *req, struct request_queue *q)
1587{
1588 struct scsi_cmnd *cmd = req->special;
1589 struct scsi_device *sdev;
1590 struct scsi_target *starget;
1591 struct Scsi_Host *shost;
1592
1593 blk_start_request(req);
1594
1595 scmd_printk(KERN_INFO, cmd, "killing request\n");
1596
1597 sdev = cmd->device;
1598 starget = scsi_target(sdev);
1599 shost = sdev->host;
1600 scsi_init_cmd_errh(cmd);
1601 cmd->result = DID_NO_CONNECT << 16;
1602 atomic_inc(&cmd->device->iorequest_cnt);
1603
1604 /*
1605 * SCSI request completion path will do scsi_device_unbusy(),
1606 * bump busy counts. To bump the counters, we need to dance
1607 * with the locks as normal issue path does.
1608 */
1609 atomic_inc(&sdev->device_busy);
1610 atomic_inc(&shost->host_busy);
1611 if (starget->can_queue > 0)
1612 atomic_inc(&starget->target_busy);
1613
1614 blk_complete_request(req);
1615}
1616
1617static void scsi_softirq_done(struct request *rq)
1618{
1619 struct scsi_cmnd *cmd = rq->special;
1620 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1621 int disposition;
1622
1623 INIT_LIST_HEAD(&cmd->eh_entry);
1624
1625 atomic_inc(&cmd->device->iodone_cnt);
1626 if (cmd->result)
1627 atomic_inc(&cmd->device->ioerr_cnt);
1628
1629 disposition = scsi_decide_disposition(cmd);
1630 if (disposition != SUCCESS &&
1631 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1632 sdev_printk(KERN_ERR, cmd->device,
1633 "timing out command, waited %lus\n",
1634 wait_for/HZ);
1635 disposition = SUCCESS;
1636 }
1637
1638 scsi_log_completion(cmd, disposition);
1639
1640 switch (disposition) {
1641 case SUCCESS:
1642 scsi_finish_command(cmd);
1643 break;
1644 case NEEDS_RETRY:
1645 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1646 break;
1647 case ADD_TO_MLQUEUE:
1648 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1649 break;
1650 default:
1651 if (!scsi_eh_scmd_add(cmd, 0))
1652 scsi_finish_command(cmd);
1653 }
1654}
1655
1656/**
1657 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1658 * @cmd: command block we are dispatching.
1659 *
1660 * Return: nonzero return request was rejected and device's queue needs to be
1661 * plugged.
1662 */
1663static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1664{
1665 struct Scsi_Host *host = cmd->device->host;
1666 int rtn = 0;
1667
1668 atomic_inc(&cmd->device->iorequest_cnt);
1669
1670 /* check if the device is still usable */
1671 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1672 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1673 * returns an immediate error upwards, and signals
1674 * that the device is no longer present */
1675 cmd->result = DID_NO_CONNECT << 16;
1676 goto done;
1677 }
1678
1679 /* Check to see if the scsi lld made this device blocked. */
1680 if (unlikely(scsi_device_blocked(cmd->device))) {
1681 /*
1682 * in blocked state, the command is just put back on
1683 * the device queue. The suspend state has already
1684 * blocked the queue so future requests should not
1685 * occur until the device transitions out of the
1686 * suspend state.
1687 */
1688 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1689 "queuecommand : device blocked\n"));
1690 return SCSI_MLQUEUE_DEVICE_BUSY;
1691 }
1692
1693 /* Store the LUN value in cmnd, if needed. */
1694 if (cmd->device->lun_in_cdb)
1695 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1696 (cmd->device->lun << 5 & 0xe0);
1697
1698 scsi_log_send(cmd);
1699
1700 /*
1701 * Before we queue this command, check if the command
1702 * length exceeds what the host adapter can handle.
1703 */
1704 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1705 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1706 "queuecommand : command too long. "
1707 "cdb_size=%d host->max_cmd_len=%d\n",
1708 cmd->cmd_len, cmd->device->host->max_cmd_len));
1709 cmd->result = (DID_ABORT << 16);
1710 goto done;
1711 }
1712
1713 if (unlikely(host->shost_state == SHOST_DEL)) {
1714 cmd->result = (DID_NO_CONNECT << 16);
1715 goto done;
1716
1717 }
1718
1719 trace_scsi_dispatch_cmd_start(cmd);
1720 rtn = host->hostt->queuecommand(host, cmd);
1721 if (rtn) {
1722 trace_scsi_dispatch_cmd_error(cmd, rtn);
1723 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1724 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1725 rtn = SCSI_MLQUEUE_HOST_BUSY;
1726
1727 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1728 "queuecommand : request rejected\n"));
1729 }
1730
1731 return rtn;
1732 done:
1733 cmd->scsi_done(cmd);
1734 return 0;
1735}
1736
1737/**
1738 * scsi_done - Invoke completion on finished SCSI command.
1739 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1740 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1741 *
1742 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1743 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1744 * calls blk_complete_request() for further processing.
1745 *
1746 * This function is interrupt context safe.
1747 */
1748static void scsi_done(struct scsi_cmnd *cmd)
1749{
1750 trace_scsi_dispatch_cmd_done(cmd);
1751 blk_complete_request(cmd->request);
1752}
1753
1754/*
1755 * Function: scsi_request_fn()
1756 *
1757 * Purpose: Main strategy routine for SCSI.
1758 *
1759 * Arguments: q - Pointer to actual queue.
1760 *
1761 * Returns: Nothing
1762 *
1763 * Lock status: IO request lock assumed to be held when called.
1764 */
1765static void scsi_request_fn(struct request_queue *q)
1766 __releases(q->queue_lock)
1767 __acquires(q->queue_lock)
1768{
1769 struct scsi_device *sdev = q->queuedata;
1770 struct Scsi_Host *shost;
1771 struct scsi_cmnd *cmd;
1772 struct request *req;
1773
1774 /*
1775 * To start with, we keep looping until the queue is empty, or until
1776 * the host is no longer able to accept any more requests.
1777 */
1778 shost = sdev->host;
1779 for (;;) {
1780 int rtn;
1781 /*
1782 * get next queueable request. We do this early to make sure
1783 * that the request is fully prepared even if we cannot
1784 * accept it.
1785 */
1786 req = blk_peek_request(q);
1787 if (!req)
1788 break;
1789
1790 if (unlikely(!scsi_device_online(sdev))) {
1791 sdev_printk(KERN_ERR, sdev,
1792 "rejecting I/O to offline device\n");
1793 scsi_kill_request(req, q);
1794 continue;
1795 }
1796
1797 if (!scsi_dev_queue_ready(q, sdev))
1798 break;
1799
1800 /*
1801 * Remove the request from the request list.
1802 */
1803 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1804 blk_start_request(req);
1805
1806 spin_unlock_irq(q->queue_lock);
1807 cmd = req->special;
1808 if (unlikely(cmd == NULL)) {
1809 printk(KERN_CRIT "impossible request in %s.\n"
1810 "please mail a stack trace to "
1811 "linux-scsi@vger.kernel.org\n",
1812 __func__);
1813 blk_dump_rq_flags(req, "foo");
1814 BUG();
1815 }
1816
1817 /*
1818 * We hit this when the driver is using a host wide
1819 * tag map. For device level tag maps the queue_depth check
1820 * in the device ready fn would prevent us from trying
1821 * to allocate a tag. Since the map is a shared host resource
1822 * we add the dev to the starved list so it eventually gets
1823 * a run when a tag is freed.
1824 */
1825 if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
1826 spin_lock_irq(shost->host_lock);
1827 if (list_empty(&sdev->starved_entry))
1828 list_add_tail(&sdev->starved_entry,
1829 &shost->starved_list);
1830 spin_unlock_irq(shost->host_lock);
1831 goto not_ready;
1832 }
1833
1834 if (!scsi_target_queue_ready(shost, sdev))
1835 goto not_ready;
1836
1837 if (!scsi_host_queue_ready(q, shost, sdev))
1838 goto host_not_ready;
1839
1840 if (sdev->simple_tags)
1841 cmd->flags |= SCMD_TAGGED;
1842 else
1843 cmd->flags &= ~SCMD_TAGGED;
1844
1845 /*
1846 * Finally, initialize any error handling parameters, and set up
1847 * the timers for timeouts.
1848 */
1849 scsi_init_cmd_errh(cmd);
1850
1851 /*
1852 * Dispatch the command to the low-level driver.
1853 */
1854 cmd->scsi_done = scsi_done;
1855 rtn = scsi_dispatch_cmd(cmd);
1856 if (rtn) {
1857 scsi_queue_insert(cmd, rtn);
1858 spin_lock_irq(q->queue_lock);
1859 goto out_delay;
1860 }
1861 spin_lock_irq(q->queue_lock);
1862 }
1863
1864 return;
1865
1866 host_not_ready:
1867 if (scsi_target(sdev)->can_queue > 0)
1868 atomic_dec(&scsi_target(sdev)->target_busy);
1869 not_ready:
1870 /*
1871 * lock q, handle tag, requeue req, and decrement device_busy. We
1872 * must return with queue_lock held.
1873 *
1874 * Decrementing device_busy without checking it is OK, as all such
1875 * cases (host limits or settings) should run the queue at some
1876 * later time.
1877 */
1878 spin_lock_irq(q->queue_lock);
1879 blk_requeue_request(q, req);
1880 atomic_dec(&sdev->device_busy);
1881out_delay:
1882 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1883 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1884}
1885
1886static inline int prep_to_mq(int ret)
1887{
1888 switch (ret) {
1889 case BLKPREP_OK:
1890 return 0;
1891 case BLKPREP_DEFER:
1892 return BLK_MQ_RQ_QUEUE_BUSY;
1893 default:
1894 return BLK_MQ_RQ_QUEUE_ERROR;
1895 }
1896}
1897
1898static int scsi_mq_prep_fn(struct request *req)
1899{
1900 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1901 struct scsi_device *sdev = req->q->queuedata;
1902 struct Scsi_Host *shost = sdev->host;
1903 unsigned char *sense_buf = cmd->sense_buffer;
1904 struct scatterlist *sg;
1905
1906 memset(cmd, 0, sizeof(struct scsi_cmnd));
1907
1908 req->special = cmd;
1909
1910 cmd->request = req;
1911 cmd->device = sdev;
1912 cmd->sense_buffer = sense_buf;
1913
1914 cmd->tag = req->tag;
1915
1916 cmd->cmnd = req->cmd;
1917 cmd->prot_op = SCSI_PROT_NORMAL;
1918
1919 INIT_LIST_HEAD(&cmd->list);
1920 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1921 cmd->jiffies_at_alloc = jiffies;
1922
1923 if (shost->use_cmd_list) {
1924 spin_lock_irq(&sdev->list_lock);
1925 list_add_tail(&cmd->list, &sdev->cmd_list);
1926 spin_unlock_irq(&sdev->list_lock);
1927 }
1928
1929 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1930 cmd->sdb.table.sgl = sg;
1931
1932 if (scsi_host_get_prot(shost)) {
1933 cmd->prot_sdb = (void *)sg +
1934 min_t(unsigned int,
1935 shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) *
1936 sizeof(struct scatterlist);
1937 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1938
1939 cmd->prot_sdb->table.sgl =
1940 (struct scatterlist *)(cmd->prot_sdb + 1);
1941 }
1942
1943 if (blk_bidi_rq(req)) {
1944 struct request *next_rq = req->next_rq;
1945 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1946
1947 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1948 bidi_sdb->table.sgl =
1949 (struct scatterlist *)(bidi_sdb + 1);
1950
1951 next_rq->special = bidi_sdb;
1952 }
1953
1954 blk_mq_start_request(req);
1955
1956 return scsi_setup_cmnd(sdev, req);
1957}
1958
1959static void scsi_mq_done(struct scsi_cmnd *cmd)
1960{
1961 trace_scsi_dispatch_cmd_done(cmd);
1962 blk_mq_complete_request(cmd->request, cmd->request->errors);
1963}
1964
1965static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1966 const struct blk_mq_queue_data *bd)
1967{
1968 struct request *req = bd->rq;
1969 struct request_queue *q = req->q;
1970 struct scsi_device *sdev = q->queuedata;
1971 struct Scsi_Host *shost = sdev->host;
1972 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1973 int ret;
1974 int reason;
1975
1976 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1977 if (ret)
1978 goto out;
1979
1980 ret = BLK_MQ_RQ_QUEUE_BUSY;
1981 if (!get_device(&sdev->sdev_gendev))
1982 goto out;
1983
1984 if (!scsi_dev_queue_ready(q, sdev))
1985 goto out_put_device;
1986 if (!scsi_target_queue_ready(shost, sdev))
1987 goto out_dec_device_busy;
1988 if (!scsi_host_queue_ready(q, shost, sdev))
1989 goto out_dec_target_busy;
1990
1991
1992 if (!(req->cmd_flags & REQ_DONTPREP)) {
1993 ret = prep_to_mq(scsi_mq_prep_fn(req));
1994 if (ret)
1995 goto out_dec_host_busy;
1996 req->cmd_flags |= REQ_DONTPREP;
1997 } else {
1998 blk_mq_start_request(req);
1999 }
2000
2001 if (sdev->simple_tags)
2002 cmd->flags |= SCMD_TAGGED;
2003 else
2004 cmd->flags &= ~SCMD_TAGGED;
2005
2006 scsi_init_cmd_errh(cmd);
2007 cmd->scsi_done = scsi_mq_done;
2008
2009 reason = scsi_dispatch_cmd(cmd);
2010 if (reason) {
2011 scsi_set_blocked(cmd, reason);
2012 ret = BLK_MQ_RQ_QUEUE_BUSY;
2013 goto out_dec_host_busy;
2014 }
2015
2016 return BLK_MQ_RQ_QUEUE_OK;
2017
2018out_dec_host_busy:
2019 atomic_dec(&shost->host_busy);
2020out_dec_target_busy:
2021 if (scsi_target(sdev)->can_queue > 0)
2022 atomic_dec(&scsi_target(sdev)->target_busy);
2023out_dec_device_busy:
2024 atomic_dec(&sdev->device_busy);
2025out_put_device:
2026 put_device(&sdev->sdev_gendev);
2027out:
2028 switch (ret) {
2029 case BLK_MQ_RQ_QUEUE_BUSY:
2030 blk_mq_stop_hw_queue(hctx);
2031 if (atomic_read(&sdev->device_busy) == 0 &&
2032 !scsi_device_blocked(sdev))
2033 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
2034 break;
2035 case BLK_MQ_RQ_QUEUE_ERROR:
2036 /*
2037 * Make sure to release all allocated ressources when
2038 * we hit an error, as we will never see this command
2039 * again.
2040 */
2041 if (req->cmd_flags & REQ_DONTPREP)
2042 scsi_mq_uninit_cmd(cmd);
2043 break;
2044 default:
2045 break;
2046 }
2047 return ret;
2048}
2049
2050static enum blk_eh_timer_return scsi_timeout(struct request *req,
2051 bool reserved)
2052{
2053 if (reserved)
2054 return BLK_EH_RESET_TIMER;
2055 return scsi_times_out(req);
2056}
2057
2058static int scsi_init_request(void *data, struct request *rq,
2059 unsigned int hctx_idx, unsigned int request_idx,
2060 unsigned int numa_node)
2061{
2062 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2063
2064 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
2065 numa_node);
2066 if (!cmd->sense_buffer)
2067 return -ENOMEM;
2068 return 0;
2069}
2070
2071static void scsi_exit_request(void *data, struct request *rq,
2072 unsigned int hctx_idx, unsigned int request_idx)
2073{
2074 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2075
2076 kfree(cmd->sense_buffer);
2077}
2078
2079static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2080{
2081 struct device *host_dev;
2082 u64 bounce_limit = 0xffffffff;
2083
2084 if (shost->unchecked_isa_dma)
2085 return BLK_BOUNCE_ISA;
2086 /*
2087 * Platforms with virtual-DMA translation
2088 * hardware have no practical limit.
2089 */
2090 if (!PCI_DMA_BUS_IS_PHYS)
2091 return BLK_BOUNCE_ANY;
2092
2093 host_dev = scsi_get_device(shost);
2094 if (host_dev && host_dev->dma_mask)
2095 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2096
2097 return bounce_limit;
2098}
2099
2100static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2101{
2102 struct device *dev = shost->dma_dev;
2103
2104 /*
2105 * this limit is imposed by hardware restrictions
2106 */
2107 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2108 SCSI_MAX_SG_CHAIN_SEGMENTS));
2109
2110 if (scsi_host_prot_dma(shost)) {
2111 shost->sg_prot_tablesize =
2112 min_not_zero(shost->sg_prot_tablesize,
2113 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2114 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2115 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2116 }
2117
2118 blk_queue_max_hw_sectors(q, shost->max_sectors);
2119 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2120 blk_queue_segment_boundary(q, shost->dma_boundary);
2121 dma_set_seg_boundary(dev, shost->dma_boundary);
2122
2123 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2124
2125 if (!shost->use_clustering)
2126 q->limits.cluster = 0;
2127
2128 /*
2129 * set a reasonable default alignment on word boundaries: the
2130 * host and device may alter it using
2131 * blk_queue_update_dma_alignment() later.
2132 */
2133 blk_queue_dma_alignment(q, 0x03);
2134}
2135
2136struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2137 request_fn_proc *request_fn)
2138{
2139 struct request_queue *q;
2140
2141 q = blk_init_queue(request_fn, NULL);
2142 if (!q)
2143 return NULL;
2144 __scsi_init_queue(shost, q);
2145 return q;
2146}
2147EXPORT_SYMBOL(__scsi_alloc_queue);
2148
2149struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2150{
2151 struct request_queue *q;
2152
2153 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2154 if (!q)
2155 return NULL;
2156
2157 blk_queue_prep_rq(q, scsi_prep_fn);
2158 blk_queue_unprep_rq(q, scsi_unprep_fn);
2159 blk_queue_softirq_done(q, scsi_softirq_done);
2160 blk_queue_rq_timed_out(q, scsi_times_out);
2161 blk_queue_lld_busy(q, scsi_lld_busy);
2162 return q;
2163}
2164
2165static struct blk_mq_ops scsi_mq_ops = {
2166 .map_queue = blk_mq_map_queue,
2167 .queue_rq = scsi_queue_rq,
2168 .complete = scsi_softirq_done,
2169 .timeout = scsi_timeout,
2170 .init_request = scsi_init_request,
2171 .exit_request = scsi_exit_request,
2172};
2173
2174struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2175{
2176 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2177 if (IS_ERR(sdev->request_queue))
2178 return NULL;
2179
2180 sdev->request_queue->queuedata = sdev;
2181 __scsi_init_queue(sdev->host, sdev->request_queue);
2182 return sdev->request_queue;
2183}
2184
2185int scsi_mq_setup_tags(struct Scsi_Host *shost)
2186{
2187 unsigned int cmd_size, sgl_size, tbl_size;
2188
2189 tbl_size = shost->sg_tablesize;
2190 if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2191 tbl_size = SCSI_MAX_SG_SEGMENTS;
2192 sgl_size = tbl_size * sizeof(struct scatterlist);
2193 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2194 if (scsi_host_get_prot(shost))
2195 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2196
2197 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2198 shost->tag_set.ops = &scsi_mq_ops;
2199 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2200 shost->tag_set.queue_depth = shost->can_queue;
2201 shost->tag_set.cmd_size = cmd_size;
2202 shost->tag_set.numa_node = NUMA_NO_NODE;
2203 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2204 shost->tag_set.flags |=
2205 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2206 shost->tag_set.driver_data = shost;
2207
2208 return blk_mq_alloc_tag_set(&shost->tag_set);
2209}
2210
2211void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2212{
2213 blk_mq_free_tag_set(&shost->tag_set);
2214}
2215
2216/*
2217 * Function: scsi_block_requests()
2218 *
2219 * Purpose: Utility function used by low-level drivers to prevent further
2220 * commands from being queued to the device.
2221 *
2222 * Arguments: shost - Host in question
2223 *
2224 * Returns: Nothing
2225 *
2226 * Lock status: No locks are assumed held.
2227 *
2228 * Notes: There is no timer nor any other means by which the requests
2229 * get unblocked other than the low-level driver calling
2230 * scsi_unblock_requests().
2231 */
2232void scsi_block_requests(struct Scsi_Host *shost)
2233{
2234 shost->host_self_blocked = 1;
2235}
2236EXPORT_SYMBOL(scsi_block_requests);
2237
2238/*
2239 * Function: scsi_unblock_requests()
2240 *
2241 * Purpose: Utility function used by low-level drivers to allow further
2242 * commands from being queued to the device.
2243 *
2244 * Arguments: shost - Host in question
2245 *
2246 * Returns: Nothing
2247 *
2248 * Lock status: No locks are assumed held.
2249 *
2250 * Notes: There is no timer nor any other means by which the requests
2251 * get unblocked other than the low-level driver calling
2252 * scsi_unblock_requests().
2253 *
2254 * This is done as an API function so that changes to the
2255 * internals of the scsi mid-layer won't require wholesale
2256 * changes to drivers that use this feature.
2257 */
2258void scsi_unblock_requests(struct Scsi_Host *shost)
2259{
2260 shost->host_self_blocked = 0;
2261 scsi_run_host_queues(shost);
2262}
2263EXPORT_SYMBOL(scsi_unblock_requests);
2264
2265int __init scsi_init_queue(void)
2266{
2267 int i;
2268
2269 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2270 sizeof(struct scsi_data_buffer),
2271 0, 0, NULL);
2272 if (!scsi_sdb_cache) {
2273 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2274 return -ENOMEM;
2275 }
2276
2277 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2278 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2279 int size = sgp->size * sizeof(struct scatterlist);
2280
2281 sgp->slab = kmem_cache_create(sgp->name, size, 0,
2282 SLAB_HWCACHE_ALIGN, NULL);
2283 if (!sgp->slab) {
2284 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2285 sgp->name);
2286 goto cleanup_sdb;
2287 }
2288
2289 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2290 sgp->slab);
2291 if (!sgp->pool) {
2292 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2293 sgp->name);
2294 goto cleanup_sdb;
2295 }
2296 }
2297
2298 return 0;
2299
2300cleanup_sdb:
2301 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2302 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2303 if (sgp->pool)
2304 mempool_destroy(sgp->pool);
2305 if (sgp->slab)
2306 kmem_cache_destroy(sgp->slab);
2307 }
2308 kmem_cache_destroy(scsi_sdb_cache);
2309
2310 return -ENOMEM;
2311}
2312
2313void scsi_exit_queue(void)
2314{
2315 int i;
2316
2317 kmem_cache_destroy(scsi_sdb_cache);
2318
2319 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2320 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2321 mempool_destroy(sgp->pool);
2322 kmem_cache_destroy(sgp->slab);
2323 }
2324}
2325
2326/**
2327 * scsi_mode_select - issue a mode select
2328 * @sdev: SCSI device to be queried
2329 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2330 * @sp: Save page bit (0 == don't save, 1 == save)
2331 * @modepage: mode page being requested
2332 * @buffer: request buffer (may not be smaller than eight bytes)
2333 * @len: length of request buffer.
2334 * @timeout: command timeout
2335 * @retries: number of retries before failing
2336 * @data: returns a structure abstracting the mode header data
2337 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2338 * must be SCSI_SENSE_BUFFERSIZE big.
2339 *
2340 * Returns zero if successful; negative error number or scsi
2341 * status on error
2342 *
2343 */
2344int
2345scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2346 unsigned char *buffer, int len, int timeout, int retries,
2347 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2348{
2349 unsigned char cmd[10];
2350 unsigned char *real_buffer;
2351 int ret;
2352
2353 memset(cmd, 0, sizeof(cmd));
2354 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2355
2356 if (sdev->use_10_for_ms) {
2357 if (len > 65535)
2358 return -EINVAL;
2359 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2360 if (!real_buffer)
2361 return -ENOMEM;
2362 memcpy(real_buffer + 8, buffer, len);
2363 len += 8;
2364 real_buffer[0] = 0;
2365 real_buffer[1] = 0;
2366 real_buffer[2] = data->medium_type;
2367 real_buffer[3] = data->device_specific;
2368 real_buffer[4] = data->longlba ? 0x01 : 0;
2369 real_buffer[5] = 0;
2370 real_buffer[6] = data->block_descriptor_length >> 8;
2371 real_buffer[7] = data->block_descriptor_length;
2372
2373 cmd[0] = MODE_SELECT_10;
2374 cmd[7] = len >> 8;
2375 cmd[8] = len;
2376 } else {
2377 if (len > 255 || data->block_descriptor_length > 255 ||
2378 data->longlba)
2379 return -EINVAL;
2380
2381 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2382 if (!real_buffer)
2383 return -ENOMEM;
2384 memcpy(real_buffer + 4, buffer, len);
2385 len += 4;
2386 real_buffer[0] = 0;
2387 real_buffer[1] = data->medium_type;
2388 real_buffer[2] = data->device_specific;
2389 real_buffer[3] = data->block_descriptor_length;
2390
2391
2392 cmd[0] = MODE_SELECT;
2393 cmd[4] = len;
2394 }
2395
2396 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2397 sshdr, timeout, retries, NULL);
2398 kfree(real_buffer);
2399 return ret;
2400}
2401EXPORT_SYMBOL_GPL(scsi_mode_select);
2402
2403/**
2404 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2405 * @sdev: SCSI device to be queried
2406 * @dbd: set if mode sense will allow block descriptors to be returned
2407 * @modepage: mode page being requested
2408 * @buffer: request buffer (may not be smaller than eight bytes)
2409 * @len: length of request buffer.
2410 * @timeout: command timeout
2411 * @retries: number of retries before failing
2412 * @data: returns a structure abstracting the mode header data
2413 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2414 * must be SCSI_SENSE_BUFFERSIZE big.
2415 *
2416 * Returns zero if unsuccessful, or the header offset (either 4
2417 * or 8 depending on whether a six or ten byte command was
2418 * issued) if successful.
2419 */
2420int
2421scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2422 unsigned char *buffer, int len, int timeout, int retries,
2423 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2424{
2425 unsigned char cmd[12];
2426 int use_10_for_ms;
2427 int header_length;
2428 int result, retry_count = retries;
2429 struct scsi_sense_hdr my_sshdr;
2430
2431 memset(data, 0, sizeof(*data));
2432 memset(&cmd[0], 0, 12);
2433 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2434 cmd[2] = modepage;
2435
2436 /* caller might not be interested in sense, but we need it */
2437 if (!sshdr)
2438 sshdr = &my_sshdr;
2439
2440 retry:
2441 use_10_for_ms = sdev->use_10_for_ms;
2442
2443 if (use_10_for_ms) {
2444 if (len < 8)
2445 len = 8;
2446
2447 cmd[0] = MODE_SENSE_10;
2448 cmd[8] = len;
2449 header_length = 8;
2450 } else {
2451 if (len < 4)
2452 len = 4;
2453
2454 cmd[0] = MODE_SENSE;
2455 cmd[4] = len;
2456 header_length = 4;
2457 }
2458
2459 memset(buffer, 0, len);
2460
2461 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2462 sshdr, timeout, retries, NULL);
2463
2464 /* This code looks awful: what it's doing is making sure an
2465 * ILLEGAL REQUEST sense return identifies the actual command
2466 * byte as the problem. MODE_SENSE commands can return
2467 * ILLEGAL REQUEST if the code page isn't supported */
2468
2469 if (use_10_for_ms && !scsi_status_is_good(result) &&
2470 (driver_byte(result) & DRIVER_SENSE)) {
2471 if (scsi_sense_valid(sshdr)) {
2472 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2473 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2474 /*
2475 * Invalid command operation code
2476 */
2477 sdev->use_10_for_ms = 0;
2478 goto retry;
2479 }
2480 }
2481 }
2482
2483 if(scsi_status_is_good(result)) {
2484 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2485 (modepage == 6 || modepage == 8))) {
2486 /* Initio breakage? */
2487 header_length = 0;
2488 data->length = 13;
2489 data->medium_type = 0;
2490 data->device_specific = 0;
2491 data->longlba = 0;
2492 data->block_descriptor_length = 0;
2493 } else if(use_10_for_ms) {
2494 data->length = buffer[0]*256 + buffer[1] + 2;
2495 data->medium_type = buffer[2];
2496 data->device_specific = buffer[3];
2497 data->longlba = buffer[4] & 0x01;
2498 data->block_descriptor_length = buffer[6]*256
2499 + buffer[7];
2500 } else {
2501 data->length = buffer[0] + 1;
2502 data->medium_type = buffer[1];
2503 data->device_specific = buffer[2];
2504 data->block_descriptor_length = buffer[3];
2505 }
2506 data->header_length = header_length;
2507 } else if ((status_byte(result) == CHECK_CONDITION) &&
2508 scsi_sense_valid(sshdr) &&
2509 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2510 retry_count--;
2511 goto retry;
2512 }
2513
2514 return result;
2515}
2516EXPORT_SYMBOL(scsi_mode_sense);
2517
2518/**
2519 * scsi_test_unit_ready - test if unit is ready
2520 * @sdev: scsi device to change the state of.
2521 * @timeout: command timeout
2522 * @retries: number of retries before failing
2523 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2524 * returning sense. Make sure that this is cleared before passing
2525 * in.
2526 *
2527 * Returns zero if unsuccessful or an error if TUR failed. For
2528 * removable media, UNIT_ATTENTION sets ->changed flag.
2529 **/
2530int
2531scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2532 struct scsi_sense_hdr *sshdr_external)
2533{
2534 char cmd[] = {
2535 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2536 };
2537 struct scsi_sense_hdr *sshdr;
2538 int result;
2539
2540 if (!sshdr_external)
2541 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2542 else
2543 sshdr = sshdr_external;
2544
2545 /* try to eat the UNIT_ATTENTION if there are enough retries */
2546 do {
2547 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2548 timeout, retries, NULL);
2549 if (sdev->removable && scsi_sense_valid(sshdr) &&
2550 sshdr->sense_key == UNIT_ATTENTION)
2551 sdev->changed = 1;
2552 } while (scsi_sense_valid(sshdr) &&
2553 sshdr->sense_key == UNIT_ATTENTION && --retries);
2554
2555 if (!sshdr_external)
2556 kfree(sshdr);
2557 return result;
2558}
2559EXPORT_SYMBOL(scsi_test_unit_ready);
2560
2561/**
2562 * scsi_device_set_state - Take the given device through the device state model.
2563 * @sdev: scsi device to change the state of.
2564 * @state: state to change to.
2565 *
2566 * Returns zero if unsuccessful or an error if the requested
2567 * transition is illegal.
2568 */
2569int
2570scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2571{
2572 enum scsi_device_state oldstate = sdev->sdev_state;
2573
2574 if (state == oldstate)
2575 return 0;
2576
2577 switch (state) {
2578 case SDEV_CREATED:
2579 switch (oldstate) {
2580 case SDEV_CREATED_BLOCK:
2581 break;
2582 default:
2583 goto illegal;
2584 }
2585 break;
2586
2587 case SDEV_RUNNING:
2588 switch (oldstate) {
2589 case SDEV_CREATED:
2590 case SDEV_OFFLINE:
2591 case SDEV_TRANSPORT_OFFLINE:
2592 case SDEV_QUIESCE:
2593 case SDEV_BLOCK:
2594 break;
2595 default:
2596 goto illegal;
2597 }
2598 break;
2599
2600 case SDEV_QUIESCE:
2601 switch (oldstate) {
2602 case SDEV_RUNNING:
2603 case SDEV_OFFLINE:
2604 case SDEV_TRANSPORT_OFFLINE:
2605 break;
2606 default:
2607 goto illegal;
2608 }
2609 break;
2610
2611 case SDEV_OFFLINE:
2612 case SDEV_TRANSPORT_OFFLINE:
2613 switch (oldstate) {
2614 case SDEV_CREATED:
2615 case SDEV_RUNNING:
2616 case SDEV_QUIESCE:
2617 case SDEV_BLOCK:
2618 break;
2619 default:
2620 goto illegal;
2621 }
2622 break;
2623
2624 case SDEV_BLOCK:
2625 switch (oldstate) {
2626 case SDEV_RUNNING:
2627 case SDEV_CREATED_BLOCK:
2628 break;
2629 default:
2630 goto illegal;
2631 }
2632 break;
2633
2634 case SDEV_CREATED_BLOCK:
2635 switch (oldstate) {
2636 case SDEV_CREATED:
2637 break;
2638 default:
2639 goto illegal;
2640 }
2641 break;
2642
2643 case SDEV_CANCEL:
2644 switch (oldstate) {
2645 case SDEV_CREATED:
2646 case SDEV_RUNNING:
2647 case SDEV_QUIESCE:
2648 case SDEV_OFFLINE:
2649 case SDEV_TRANSPORT_OFFLINE:
2650 case SDEV_BLOCK:
2651 break;
2652 default:
2653 goto illegal;
2654 }
2655 break;
2656
2657 case SDEV_DEL:
2658 switch (oldstate) {
2659 case SDEV_CREATED:
2660 case SDEV_RUNNING:
2661 case SDEV_OFFLINE:
2662 case SDEV_TRANSPORT_OFFLINE:
2663 case SDEV_CANCEL:
2664 case SDEV_CREATED_BLOCK:
2665 break;
2666 default:
2667 goto illegal;
2668 }
2669 break;
2670
2671 }
2672 sdev->sdev_state = state;
2673 return 0;
2674
2675 illegal:
2676 SCSI_LOG_ERROR_RECOVERY(1,
2677 sdev_printk(KERN_ERR, sdev,
2678 "Illegal state transition %s->%s",
2679 scsi_device_state_name(oldstate),
2680 scsi_device_state_name(state))
2681 );
2682 return -EINVAL;
2683}
2684EXPORT_SYMBOL(scsi_device_set_state);
2685
2686/**
2687 * sdev_evt_emit - emit a single SCSI device uevent
2688 * @sdev: associated SCSI device
2689 * @evt: event to emit
2690 *
2691 * Send a single uevent (scsi_event) to the associated scsi_device.
2692 */
2693static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2694{
2695 int idx = 0;
2696 char *envp[3];
2697
2698 switch (evt->evt_type) {
2699 case SDEV_EVT_MEDIA_CHANGE:
2700 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2701 break;
2702 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2703 scsi_rescan_device(&sdev->sdev_gendev);
2704 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2705 break;
2706 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2707 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2708 break;
2709 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2710 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2711 break;
2712 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2713 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2714 break;
2715 case SDEV_EVT_LUN_CHANGE_REPORTED:
2716 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2717 break;
2718 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2719 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2720 break;
2721 default:
2722 /* do nothing */
2723 break;
2724 }
2725
2726 envp[idx++] = NULL;
2727
2728 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2729}
2730
2731/**
2732 * sdev_evt_thread - send a uevent for each scsi event
2733 * @work: work struct for scsi_device
2734 *
2735 * Dispatch queued events to their associated scsi_device kobjects
2736 * as uevents.
2737 */
2738void scsi_evt_thread(struct work_struct *work)
2739{
2740 struct scsi_device *sdev;
2741 enum scsi_device_event evt_type;
2742 LIST_HEAD(event_list);
2743
2744 sdev = container_of(work, struct scsi_device, event_work);
2745
2746 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2747 if (test_and_clear_bit(evt_type, sdev->pending_events))
2748 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2749
2750 while (1) {
2751 struct scsi_event *evt;
2752 struct list_head *this, *tmp;
2753 unsigned long flags;
2754
2755 spin_lock_irqsave(&sdev->list_lock, flags);
2756 list_splice_init(&sdev->event_list, &event_list);
2757 spin_unlock_irqrestore(&sdev->list_lock, flags);
2758
2759 if (list_empty(&event_list))
2760 break;
2761
2762 list_for_each_safe(this, tmp, &event_list) {
2763 evt = list_entry(this, struct scsi_event, node);
2764 list_del(&evt->node);
2765 scsi_evt_emit(sdev, evt);
2766 kfree(evt);
2767 }
2768 }
2769}
2770
2771/**
2772 * sdev_evt_send - send asserted event to uevent thread
2773 * @sdev: scsi_device event occurred on
2774 * @evt: event to send
2775 *
2776 * Assert scsi device event asynchronously.
2777 */
2778void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2779{
2780 unsigned long flags;
2781
2782#if 0
2783 /* FIXME: currently this check eliminates all media change events
2784 * for polled devices. Need to update to discriminate between AN
2785 * and polled events */
2786 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2787 kfree(evt);
2788 return;
2789 }
2790#endif
2791
2792 spin_lock_irqsave(&sdev->list_lock, flags);
2793 list_add_tail(&evt->node, &sdev->event_list);
2794 schedule_work(&sdev->event_work);
2795 spin_unlock_irqrestore(&sdev->list_lock, flags);
2796}
2797EXPORT_SYMBOL_GPL(sdev_evt_send);
2798
2799/**
2800 * sdev_evt_alloc - allocate a new scsi event
2801 * @evt_type: type of event to allocate
2802 * @gfpflags: GFP flags for allocation
2803 *
2804 * Allocates and returns a new scsi_event.
2805 */
2806struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2807 gfp_t gfpflags)
2808{
2809 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2810 if (!evt)
2811 return NULL;
2812
2813 evt->evt_type = evt_type;
2814 INIT_LIST_HEAD(&evt->node);
2815
2816 /* evt_type-specific initialization, if any */
2817 switch (evt_type) {
2818 case SDEV_EVT_MEDIA_CHANGE:
2819 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2820 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2821 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2822 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2823 case SDEV_EVT_LUN_CHANGE_REPORTED:
2824 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2825 default:
2826 /* do nothing */
2827 break;
2828 }
2829
2830 return evt;
2831}
2832EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2833
2834/**
2835 * sdev_evt_send_simple - send asserted event to uevent thread
2836 * @sdev: scsi_device event occurred on
2837 * @evt_type: type of event to send
2838 * @gfpflags: GFP flags for allocation
2839 *
2840 * Assert scsi device event asynchronously, given an event type.
2841 */
2842void sdev_evt_send_simple(struct scsi_device *sdev,
2843 enum scsi_device_event evt_type, gfp_t gfpflags)
2844{
2845 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2846 if (!evt) {
2847 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2848 evt_type);
2849 return;
2850 }
2851
2852 sdev_evt_send(sdev, evt);
2853}
2854EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2855
2856/**
2857 * scsi_device_quiesce - Block user issued commands.
2858 * @sdev: scsi device to quiesce.
2859 *
2860 * This works by trying to transition to the SDEV_QUIESCE state
2861 * (which must be a legal transition). When the device is in this
2862 * state, only special requests will be accepted, all others will
2863 * be deferred. Since special requests may also be requeued requests,
2864 * a successful return doesn't guarantee the device will be
2865 * totally quiescent.
2866 *
2867 * Must be called with user context, may sleep.
2868 *
2869 * Returns zero if unsuccessful or an error if not.
2870 */
2871int
2872scsi_device_quiesce(struct scsi_device *sdev)
2873{
2874 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2875 if (err)
2876 return err;
2877
2878 scsi_run_queue(sdev->request_queue);
2879 while (atomic_read(&sdev->device_busy)) {
2880 msleep_interruptible(200);
2881 scsi_run_queue(sdev->request_queue);
2882 }
2883 return 0;
2884}
2885EXPORT_SYMBOL(scsi_device_quiesce);
2886
2887/**
2888 * scsi_device_resume - Restart user issued commands to a quiesced device.
2889 * @sdev: scsi device to resume.
2890 *
2891 * Moves the device from quiesced back to running and restarts the
2892 * queues.
2893 *
2894 * Must be called with user context, may sleep.
2895 */
2896void scsi_device_resume(struct scsi_device *sdev)
2897{
2898 /* check if the device state was mutated prior to resume, and if
2899 * so assume the state is being managed elsewhere (for example
2900 * device deleted during suspend)
2901 */
2902 if (sdev->sdev_state != SDEV_QUIESCE ||
2903 scsi_device_set_state(sdev, SDEV_RUNNING))
2904 return;
2905 scsi_run_queue(sdev->request_queue);
2906}
2907EXPORT_SYMBOL(scsi_device_resume);
2908
2909static void
2910device_quiesce_fn(struct scsi_device *sdev, void *data)
2911{
2912 scsi_device_quiesce(sdev);
2913}
2914
2915void
2916scsi_target_quiesce(struct scsi_target *starget)
2917{
2918 starget_for_each_device(starget, NULL, device_quiesce_fn);
2919}
2920EXPORT_SYMBOL(scsi_target_quiesce);
2921
2922static void
2923device_resume_fn(struct scsi_device *sdev, void *data)
2924{
2925 scsi_device_resume(sdev);
2926}
2927
2928void
2929scsi_target_resume(struct scsi_target *starget)
2930{
2931 starget_for_each_device(starget, NULL, device_resume_fn);
2932}
2933EXPORT_SYMBOL(scsi_target_resume);
2934
2935/**
2936 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2937 * @sdev: device to block
2938 *
2939 * Block request made by scsi lld's to temporarily stop all
2940 * scsi commands on the specified device. Called from interrupt
2941 * or normal process context.
2942 *
2943 * Returns zero if successful or error if not
2944 *
2945 * Notes:
2946 * This routine transitions the device to the SDEV_BLOCK state
2947 * (which must be a legal transition). When the device is in this
2948 * state, all commands are deferred until the scsi lld reenables
2949 * the device with scsi_device_unblock or device_block_tmo fires.
2950 */
2951int
2952scsi_internal_device_block(struct scsi_device *sdev)
2953{
2954 struct request_queue *q = sdev->request_queue;
2955 unsigned long flags;
2956 int err = 0;
2957
2958 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2959 if (err) {
2960 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2961
2962 if (err)
2963 return err;
2964 }
2965
2966 /*
2967 * The device has transitioned to SDEV_BLOCK. Stop the
2968 * block layer from calling the midlayer with this device's
2969 * request queue.
2970 */
2971 if (q->mq_ops) {
2972 blk_mq_stop_hw_queues(q);
2973 } else {
2974 spin_lock_irqsave(q->queue_lock, flags);
2975 blk_stop_queue(q);
2976 spin_unlock_irqrestore(q->queue_lock, flags);
2977 }
2978
2979 return 0;
2980}
2981EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2982
2983/**
2984 * scsi_internal_device_unblock - resume a device after a block request
2985 * @sdev: device to resume
2986 * @new_state: state to set devices to after unblocking
2987 *
2988 * Called by scsi lld's or the midlayer to restart the device queue
2989 * for the previously suspended scsi device. Called from interrupt or
2990 * normal process context.
2991 *
2992 * Returns zero if successful or error if not.
2993 *
2994 * Notes:
2995 * This routine transitions the device to the SDEV_RUNNING state
2996 * or to one of the offline states (which must be a legal transition)
2997 * allowing the midlayer to goose the queue for this device.
2998 */
2999int
3000scsi_internal_device_unblock(struct scsi_device *sdev,
3001 enum scsi_device_state new_state)
3002{
3003 struct request_queue *q = sdev->request_queue;
3004 unsigned long flags;
3005
3006 /*
3007 * Try to transition the scsi device to SDEV_RUNNING or one of the
3008 * offlined states and goose the device queue if successful.
3009 */
3010 if ((sdev->sdev_state == SDEV_BLOCK) ||
3011 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
3012 sdev->sdev_state = new_state;
3013 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
3014 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3015 new_state == SDEV_OFFLINE)
3016 sdev->sdev_state = new_state;
3017 else
3018 sdev->sdev_state = SDEV_CREATED;
3019 } else if (sdev->sdev_state != SDEV_CANCEL &&
3020 sdev->sdev_state != SDEV_OFFLINE)
3021 return -EINVAL;
3022
3023 if (q->mq_ops) {
3024 blk_mq_start_stopped_hw_queues(q, false);
3025 } else {
3026 spin_lock_irqsave(q->queue_lock, flags);
3027 blk_start_queue(q);
3028 spin_unlock_irqrestore(q->queue_lock, flags);
3029 }
3030
3031 return 0;
3032}
3033EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
3034
3035static void
3036device_block(struct scsi_device *sdev, void *data)
3037{
3038 scsi_internal_device_block(sdev);
3039}
3040
3041static int
3042target_block(struct device *dev, void *data)
3043{
3044 if (scsi_is_target_device(dev))
3045 starget_for_each_device(to_scsi_target(dev), NULL,
3046 device_block);
3047 return 0;
3048}
3049
3050void
3051scsi_target_block(struct device *dev)
3052{
3053 if (scsi_is_target_device(dev))
3054 starget_for_each_device(to_scsi_target(dev), NULL,
3055 device_block);
3056 else
3057 device_for_each_child(dev, NULL, target_block);
3058}
3059EXPORT_SYMBOL_GPL(scsi_target_block);
3060
3061static void
3062device_unblock(struct scsi_device *sdev, void *data)
3063{
3064 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3065}
3066
3067static int
3068target_unblock(struct device *dev, void *data)
3069{
3070 if (scsi_is_target_device(dev))
3071 starget_for_each_device(to_scsi_target(dev), data,
3072 device_unblock);
3073 return 0;
3074}
3075
3076void
3077scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3078{
3079 if (scsi_is_target_device(dev))
3080 starget_for_each_device(to_scsi_target(dev), &new_state,
3081 device_unblock);
3082 else
3083 device_for_each_child(dev, &new_state, target_unblock);
3084}
3085EXPORT_SYMBOL_GPL(scsi_target_unblock);
3086
3087/**
3088 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3089 * @sgl: scatter-gather list
3090 * @sg_count: number of segments in sg
3091 * @offset: offset in bytes into sg, on return offset into the mapped area
3092 * @len: bytes to map, on return number of bytes mapped
3093 *
3094 * Returns virtual address of the start of the mapped page
3095 */
3096void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3097 size_t *offset, size_t *len)
3098{
3099 int i;
3100 size_t sg_len = 0, len_complete = 0;
3101 struct scatterlist *sg;
3102 struct page *page;
3103
3104 WARN_ON(!irqs_disabled());
3105
3106 for_each_sg(sgl, sg, sg_count, i) {
3107 len_complete = sg_len; /* Complete sg-entries */
3108 sg_len += sg->length;
3109 if (sg_len > *offset)
3110 break;
3111 }
3112
3113 if (unlikely(i == sg_count)) {
3114 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3115 "elements %d\n",
3116 __func__, sg_len, *offset, sg_count);
3117 WARN_ON(1);
3118 return NULL;
3119 }
3120
3121 /* Offset starting from the beginning of first page in this sg-entry */
3122 *offset = *offset - len_complete + sg->offset;
3123
3124 /* Assumption: contiguous pages can be accessed as "page + i" */
3125 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3126 *offset &= ~PAGE_MASK;
3127
3128 /* Bytes in this sg-entry from *offset to the end of the page */
3129 sg_len = PAGE_SIZE - *offset;
3130 if (*len > sg_len)
3131 *len = sg_len;
3132
3133 return kmap_atomic(page);
3134}
3135EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3136
3137/**
3138 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3139 * @virt: virtual address to be unmapped
3140 */
3141void scsi_kunmap_atomic_sg(void *virt)
3142{
3143 kunmap_atomic(virt);
3144}
3145EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3146
3147void sdev_disable_disk_events(struct scsi_device *sdev)
3148{
3149 atomic_inc(&sdev->disk_events_disable_depth);
3150}
3151EXPORT_SYMBOL(sdev_disable_disk_events);
3152
3153void sdev_enable_disk_events(struct scsi_device *sdev)
3154{
3155 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3156 return;
3157 atomic_dec(&sdev->disk_events_disable_depth);
3158}
3159EXPORT_SYMBOL(sdev_enable_disk_events);
3160
3161/**
3162 * scsi_vpd_lun_id - return a unique device identification
3163 * @sdev: SCSI device
3164 * @id: buffer for the identification
3165 * @id_len: length of the buffer
3166 *
3167 * Copies a unique device identification into @id based
3168 * on the information in the VPD page 0x83 of the device.
3169 * The string will be formatted as a SCSI name string.
3170 *
3171 * Returns the length of the identification or error on failure.
3172 * If the identifier is longer than the supplied buffer the actual
3173 * identifier length is returned and the buffer is not zero-padded.
3174 */
3175int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3176{
3177 u8 cur_id_type = 0xff;
3178 u8 cur_id_size = 0;
3179 unsigned char *d, *cur_id_str;
3180 unsigned char __rcu *vpd_pg83;
3181 int id_size = -EINVAL;
3182
3183 rcu_read_lock();
3184 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3185 if (!vpd_pg83) {
3186 rcu_read_unlock();
3187 return -ENXIO;
3188 }
3189
3190 /*
3191 * Look for the correct descriptor.
3192 * Order of preference for lun descriptor:
3193 * - SCSI name string
3194 * - NAA IEEE Registered Extended
3195 * - EUI-64 based 16-byte
3196 * - EUI-64 based 12-byte
3197 * - NAA IEEE Registered
3198 * - NAA IEEE Extended
3199 * as longer descriptors reduce the likelyhood
3200 * of identification clashes.
3201 */
3202
3203 /* The id string must be at least 20 bytes + terminating NULL byte */
3204 if (id_len < 21) {
3205 rcu_read_unlock();
3206 return -EINVAL;
3207 }
3208
3209 memset(id, 0, id_len);
3210 d = vpd_pg83 + 4;
3211 while (d < vpd_pg83 + sdev->vpd_pg83_len) {
3212 /* Skip designators not referring to the LUN */
3213 if ((d[1] & 0x30) != 0x00)
3214 goto next_desig;
3215
3216 switch (d[1] & 0xf) {
3217 case 0x2:
3218 /* EUI-64 */
3219 if (cur_id_size > d[3])
3220 break;
3221 /* Prefer NAA IEEE Registered Extended */
3222 if (cur_id_type == 0x3 &&
3223 cur_id_size == d[3])
3224 break;
3225 cur_id_size = d[3];
3226 cur_id_str = d + 4;
3227 cur_id_type = d[1] & 0xf;
3228 switch (cur_id_size) {
3229 case 8:
3230 id_size = snprintf(id, id_len,
3231 "eui.%8phN",
3232 cur_id_str);
3233 break;
3234 case 12:
3235 id_size = snprintf(id, id_len,
3236 "eui.%12phN",
3237 cur_id_str);
3238 break;
3239 case 16:
3240 id_size = snprintf(id, id_len,
3241 "eui.%16phN",
3242 cur_id_str);
3243 break;
3244 default:
3245 cur_id_size = 0;
3246 break;
3247 }
3248 break;
3249 case 0x3:
3250 /* NAA */
3251 if (cur_id_size > d[3])
3252 break;
3253 cur_id_size = d[3];
3254 cur_id_str = d + 4;
3255 cur_id_type = d[1] & 0xf;
3256 switch (cur_id_size) {
3257 case 8:
3258 id_size = snprintf(id, id_len,
3259 "naa.%8phN",
3260 cur_id_str);
3261 break;
3262 case 16:
3263 id_size = snprintf(id, id_len,
3264 "naa.%16phN",
3265 cur_id_str);
3266 break;
3267 default:
3268 cur_id_size = 0;
3269 break;
3270 }
3271 break;
3272 case 0x8:
3273 /* SCSI name string */
3274 if (cur_id_size + 4 > d[3])
3275 break;
3276 /* Prefer others for truncated descriptor */
3277 if (cur_id_size && d[3] > id_len)
3278 break;
3279 cur_id_size = id_size = d[3];
3280 cur_id_str = d + 4;
3281 cur_id_type = d[1] & 0xf;
3282 if (cur_id_size >= id_len)
3283 cur_id_size = id_len - 1;
3284 memcpy(id, cur_id_str, cur_id_size);
3285 /* Decrease priority for truncated descriptor */
3286 if (cur_id_size != id_size)
3287 cur_id_size = 6;
3288 break;
3289 default:
3290 break;
3291 }
3292next_desig:
3293 d += d[3] + 4;
3294 }
3295 rcu_read_unlock();
3296
3297 return id_size;
3298}
3299EXPORT_SYMBOL(scsi_vpd_lun_id);
3300
3301/*
3302 * scsi_vpd_tpg_id - return a target port group identifier
3303 * @sdev: SCSI device
3304 *
3305 * Returns the Target Port Group identifier from the information
3306 * froom VPD page 0x83 of the device.
3307 *
3308 * Returns the identifier or error on failure.
3309 */
3310int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3311{
3312 unsigned char *d;
3313 unsigned char __rcu *vpd_pg83;
3314 int group_id = -EAGAIN, rel_port = -1;
3315
3316 rcu_read_lock();
3317 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3318 if (!vpd_pg83) {
3319 rcu_read_unlock();
3320 return -ENXIO;
3321 }
3322
3323 d = sdev->vpd_pg83 + 4;
3324 while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
3325 switch (d[1] & 0xf) {
3326 case 0x4:
3327 /* Relative target port */
3328 rel_port = get_unaligned_be16(&d[6]);
3329 break;
3330 case 0x5:
3331 /* Target port group */
3332 group_id = get_unaligned_be16(&d[6]);
3333 break;
3334 default:
3335 break;
3336 }
3337 d += d[3] + 4;
3338 }
3339 rcu_read_unlock();
3340
3341 if (group_id >= 0 && rel_id && rel_port != -1)
3342 *rel_id = rel_port;
3343
3344 return group_id;
3345}
3346EXPORT_SYMBOL(scsi_vpd_tpg_id);
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 blk_mq_requeue_request(rq, false);
126 if (!scsi_host_in_recovery(cmd->device->host))
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128}
129
130/**
131 * __scsi_queue_insert - private queue insertion
132 * @cmd: The SCSI command being requeued
133 * @reason: The reason for the requeue
134 * @unbusy: Whether the queue should be unbusied
135 *
136 * This is a private queue insertion. The public interface
137 * scsi_queue_insert() always assumes the queue should be unbusied
138 * because it's always called before the completion. This function is
139 * for a requeue after completion, which should only occur in this
140 * file.
141 */
142static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
143{
144 struct scsi_device *device = cmd->device;
145
146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 "Inserting command %p into mlqueue\n", cmd));
148
149 scsi_set_blocked(cmd, reason);
150
151 /*
152 * Decrement the counters, since these commands are no longer
153 * active on the host/device.
154 */
155 if (unbusy)
156 scsi_device_unbusy(device, cmd);
157
158 /*
159 * Requeue this command. It will go before all other commands
160 * that are already in the queue. Schedule requeue work under
161 * lock such that the kblockd_schedule_work() call happens
162 * before blk_mq_destroy_queue() finishes.
163 */
164 cmd->result = 0;
165
166 blk_mq_requeue_request(scsi_cmd_to_rq(cmd),
167 !scsi_host_in_recovery(cmd->device->host));
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
187void scsi_failures_reset_retries(struct scsi_failures *failures)
188{
189 struct scsi_failure *failure;
190
191 failures->total_retries = 0;
192
193 for (failure = failures->failure_definitions; failure->result;
194 failure++)
195 failure->retries = 0;
196}
197EXPORT_SYMBOL_GPL(scsi_failures_reset_retries);
198
199/**
200 * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
201 * @scmd: scsi_cmnd to check.
202 * @failures: scsi_failures struct that lists failures to check for.
203 *
204 * Returns -EAGAIN if the caller should retry else 0.
205 */
206static int scsi_check_passthrough(struct scsi_cmnd *scmd,
207 struct scsi_failures *failures)
208{
209 struct scsi_failure *failure;
210 struct scsi_sense_hdr sshdr;
211 enum sam_status status;
212
213 if (!failures)
214 return 0;
215
216 for (failure = failures->failure_definitions; failure->result;
217 failure++) {
218 if (failure->result == SCMD_FAILURE_RESULT_ANY)
219 goto maybe_retry;
220
221 if (host_byte(scmd->result) &&
222 host_byte(scmd->result) == host_byte(failure->result))
223 goto maybe_retry;
224
225 status = status_byte(scmd->result);
226 if (!status)
227 continue;
228
229 if (failure->result == SCMD_FAILURE_STAT_ANY &&
230 !scsi_status_is_good(scmd->result))
231 goto maybe_retry;
232
233 if (status != status_byte(failure->result))
234 continue;
235
236 if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
237 failure->sense == SCMD_FAILURE_SENSE_ANY)
238 goto maybe_retry;
239
240 if (!scsi_command_normalize_sense(scmd, &sshdr))
241 return 0;
242
243 if (failure->sense != sshdr.sense_key)
244 continue;
245
246 if (failure->asc == SCMD_FAILURE_ASC_ANY)
247 goto maybe_retry;
248
249 if (failure->asc != sshdr.asc)
250 continue;
251
252 if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
253 failure->ascq == sshdr.ascq)
254 goto maybe_retry;
255 }
256
257 return 0;
258
259maybe_retry:
260 if (failure->allowed) {
261 if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
262 ++failure->retries <= failure->allowed)
263 return -EAGAIN;
264 } else {
265 if (failures->total_allowed == SCMD_FAILURE_NO_LIMIT ||
266 ++failures->total_retries <= failures->total_allowed)
267 return -EAGAIN;
268 }
269
270 return 0;
271}
272
273/**
274 * scsi_execute_cmd - insert request and wait for the result
275 * @sdev: scsi_device
276 * @cmd: scsi command
277 * @opf: block layer request cmd_flags
278 * @buffer: data buffer
279 * @bufflen: len of buffer
280 * @timeout: request timeout in HZ
281 * @ml_retries: number of times SCSI midlayer will retry request
282 * @args: Optional args. See struct definition for field descriptions
283 *
284 * Returns the scsi_cmnd result field if a command was executed, or a negative
285 * Linux error code if we didn't get that far.
286 */
287int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
288 blk_opf_t opf, void *buffer, unsigned int bufflen,
289 int timeout, int ml_retries,
290 const struct scsi_exec_args *args)
291{
292 static const struct scsi_exec_args default_args;
293 struct request *req;
294 struct scsi_cmnd *scmd;
295 int ret;
296
297 if (!args)
298 args = &default_args;
299 else if (WARN_ON_ONCE(args->sense &&
300 args->sense_len != SCSI_SENSE_BUFFERSIZE))
301 return -EINVAL;
302
303retry:
304 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
305 if (IS_ERR(req))
306 return PTR_ERR(req);
307
308 if (bufflen) {
309 ret = blk_rq_map_kern(sdev->request_queue, req,
310 buffer, bufflen, GFP_NOIO);
311 if (ret)
312 goto out;
313 }
314 scmd = blk_mq_rq_to_pdu(req);
315 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
316 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
317 scmd->allowed = ml_retries;
318 scmd->flags |= args->scmd_flags;
319 req->timeout = timeout;
320 req->rq_flags |= RQF_QUIET;
321
322 /*
323 * head injection *required* here otherwise quiesce won't work
324 */
325 blk_execute_rq(req, true);
326
327 if (scsi_check_passthrough(scmd, args->failures) == -EAGAIN) {
328 blk_mq_free_request(req);
329 goto retry;
330 }
331
332 /*
333 * Some devices (USB mass-storage in particular) may transfer
334 * garbage data together with a residue indicating that the data
335 * is invalid. Prevent the garbage from being misinterpreted
336 * and prevent security leaks by zeroing out the excess data.
337 */
338 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
339 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
340
341 if (args->resid)
342 *args->resid = scmd->resid_len;
343 if (args->sense)
344 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
345 if (args->sshdr)
346 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
347 args->sshdr);
348
349 ret = scmd->result;
350 out:
351 blk_mq_free_request(req);
352
353 return ret;
354}
355EXPORT_SYMBOL(scsi_execute_cmd);
356
357/*
358 * Wake up the error handler if necessary. Avoid as follows that the error
359 * handler is not woken up if host in-flight requests number ==
360 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
361 * with an RCU read lock in this function to ensure that this function in
362 * its entirety either finishes before scsi_eh_scmd_add() increases the
363 * host_failed counter or that it notices the shost state change made by
364 * scsi_eh_scmd_add().
365 */
366static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
367{
368 unsigned long flags;
369
370 rcu_read_lock();
371 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
372 if (unlikely(scsi_host_in_recovery(shost))) {
373 unsigned int busy = scsi_host_busy(shost);
374
375 spin_lock_irqsave(shost->host_lock, flags);
376 if (shost->host_failed || shost->host_eh_scheduled)
377 scsi_eh_wakeup(shost, busy);
378 spin_unlock_irqrestore(shost->host_lock, flags);
379 }
380 rcu_read_unlock();
381}
382
383void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
384{
385 struct Scsi_Host *shost = sdev->host;
386 struct scsi_target *starget = scsi_target(sdev);
387
388 scsi_dec_host_busy(shost, cmd);
389
390 if (starget->can_queue > 0)
391 atomic_dec(&starget->target_busy);
392
393 sbitmap_put(&sdev->budget_map, cmd->budget_token);
394 cmd->budget_token = -1;
395}
396
397/*
398 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
399 * interrupts disabled.
400 */
401static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
402{
403 struct scsi_device *current_sdev = data;
404
405 if (sdev != current_sdev)
406 blk_mq_run_hw_queues(sdev->request_queue, true);
407}
408
409/*
410 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
411 * and call blk_run_queue for all the scsi_devices on the target -
412 * including current_sdev first.
413 *
414 * Called with *no* scsi locks held.
415 */
416static void scsi_single_lun_run(struct scsi_device *current_sdev)
417{
418 struct Scsi_Host *shost = current_sdev->host;
419 struct scsi_target *starget = scsi_target(current_sdev);
420 unsigned long flags;
421
422 spin_lock_irqsave(shost->host_lock, flags);
423 starget->starget_sdev_user = NULL;
424 spin_unlock_irqrestore(shost->host_lock, flags);
425
426 /*
427 * Call blk_run_queue for all LUNs on the target, starting with
428 * current_sdev. We race with others (to set starget_sdev_user),
429 * but in most cases, we will be first. Ideally, each LU on the
430 * target would get some limited time or requests on the target.
431 */
432 blk_mq_run_hw_queues(current_sdev->request_queue,
433 shost->queuecommand_may_block);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 if (!starget->starget_sdev_user)
437 __starget_for_each_device(starget, current_sdev,
438 scsi_kick_sdev_queue);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440}
441
442static inline bool scsi_device_is_busy(struct scsi_device *sdev)
443{
444 if (scsi_device_busy(sdev) >= sdev->queue_depth)
445 return true;
446 if (atomic_read(&sdev->device_blocked) > 0)
447 return true;
448 return false;
449}
450
451static inline bool scsi_target_is_busy(struct scsi_target *starget)
452{
453 if (starget->can_queue > 0) {
454 if (atomic_read(&starget->target_busy) >= starget->can_queue)
455 return true;
456 if (atomic_read(&starget->target_blocked) > 0)
457 return true;
458 }
459 return false;
460}
461
462static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
463{
464 if (atomic_read(&shost->host_blocked) > 0)
465 return true;
466 if (shost->host_self_blocked)
467 return true;
468 return false;
469}
470
471static void scsi_starved_list_run(struct Scsi_Host *shost)
472{
473 LIST_HEAD(starved_list);
474 struct scsi_device *sdev;
475 unsigned long flags;
476
477 spin_lock_irqsave(shost->host_lock, flags);
478 list_splice_init(&shost->starved_list, &starved_list);
479
480 while (!list_empty(&starved_list)) {
481 struct request_queue *slq;
482
483 /*
484 * As long as shost is accepting commands and we have
485 * starved queues, call blk_run_queue. scsi_request_fn
486 * drops the queue_lock and can add us back to the
487 * starved_list.
488 *
489 * host_lock protects the starved_list and starved_entry.
490 * scsi_request_fn must get the host_lock before checking
491 * or modifying starved_list or starved_entry.
492 */
493 if (scsi_host_is_busy(shost))
494 break;
495
496 sdev = list_entry(starved_list.next,
497 struct scsi_device, starved_entry);
498 list_del_init(&sdev->starved_entry);
499 if (scsi_target_is_busy(scsi_target(sdev))) {
500 list_move_tail(&sdev->starved_entry,
501 &shost->starved_list);
502 continue;
503 }
504
505 /*
506 * Once we drop the host lock, a racing scsi_remove_device()
507 * call may remove the sdev from the starved list and destroy
508 * it and the queue. Mitigate by taking a reference to the
509 * queue and never touching the sdev again after we drop the
510 * host lock. Note: if __scsi_remove_device() invokes
511 * blk_mq_destroy_queue() before the queue is run from this
512 * function then blk_run_queue() will return immediately since
513 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
514 */
515 slq = sdev->request_queue;
516 if (!blk_get_queue(slq))
517 continue;
518 spin_unlock_irqrestore(shost->host_lock, flags);
519
520 blk_mq_run_hw_queues(slq, false);
521 blk_put_queue(slq);
522
523 spin_lock_irqsave(shost->host_lock, flags);
524 }
525 /* put any unprocessed entries back */
526 list_splice(&starved_list, &shost->starved_list);
527 spin_unlock_irqrestore(shost->host_lock, flags);
528}
529
530/**
531 * scsi_run_queue - Select a proper request queue to serve next.
532 * @q: last request's queue
533 *
534 * The previous command was completely finished, start a new one if possible.
535 */
536static void scsi_run_queue(struct request_queue *q)
537{
538 struct scsi_device *sdev = q->queuedata;
539
540 if (scsi_target(sdev)->single_lun)
541 scsi_single_lun_run(sdev);
542 if (!list_empty(&sdev->host->starved_list))
543 scsi_starved_list_run(sdev->host);
544
545 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
546 blk_mq_kick_requeue_list(q);
547}
548
549void scsi_requeue_run_queue(struct work_struct *work)
550{
551 struct scsi_device *sdev;
552 struct request_queue *q;
553
554 sdev = container_of(work, struct scsi_device, requeue_work);
555 q = sdev->request_queue;
556 scsi_run_queue(q);
557}
558
559void scsi_run_host_queues(struct Scsi_Host *shost)
560{
561 struct scsi_device *sdev;
562
563 shost_for_each_device(sdev, shost)
564 scsi_run_queue(sdev->request_queue);
565}
566
567static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
568{
569 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
570 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
571
572 if (drv->uninit_command)
573 drv->uninit_command(cmd);
574 }
575}
576
577void scsi_free_sgtables(struct scsi_cmnd *cmd)
578{
579 if (cmd->sdb.table.nents)
580 sg_free_table_chained(&cmd->sdb.table,
581 SCSI_INLINE_SG_CNT);
582 if (scsi_prot_sg_count(cmd))
583 sg_free_table_chained(&cmd->prot_sdb->table,
584 SCSI_INLINE_PROT_SG_CNT);
585}
586EXPORT_SYMBOL_GPL(scsi_free_sgtables);
587
588static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
589{
590 scsi_free_sgtables(cmd);
591 scsi_uninit_cmd(cmd);
592}
593
594static void scsi_run_queue_async(struct scsi_device *sdev)
595{
596 if (scsi_host_in_recovery(sdev->host))
597 return;
598
599 if (scsi_target(sdev)->single_lun ||
600 !list_empty(&sdev->host->starved_list)) {
601 kblockd_schedule_work(&sdev->requeue_work);
602 } else {
603 /*
604 * smp_mb() present in sbitmap_queue_clear() or implied in
605 * .end_io is for ordering writing .device_busy in
606 * scsi_device_unbusy() and reading sdev->restarts.
607 */
608 int old = atomic_read(&sdev->restarts);
609
610 /*
611 * ->restarts has to be kept as non-zero if new budget
612 * contention occurs.
613 *
614 * No need to run queue when either another re-run
615 * queue wins in updating ->restarts or a new budget
616 * contention occurs.
617 */
618 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
619 blk_mq_run_hw_queues(sdev->request_queue, true);
620 }
621}
622
623/* Returns false when no more bytes to process, true if there are more */
624static bool scsi_end_request(struct request *req, blk_status_t error,
625 unsigned int bytes)
626{
627 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
628 struct scsi_device *sdev = cmd->device;
629 struct request_queue *q = sdev->request_queue;
630
631 if (blk_update_request(req, error, bytes))
632 return true;
633
634 // XXX:
635 if (blk_queue_add_random(q))
636 add_disk_randomness(req->q->disk);
637
638 WARN_ON_ONCE(!blk_rq_is_passthrough(req) &&
639 !(cmd->flags & SCMD_INITIALIZED));
640 cmd->flags = 0;
641
642 /*
643 * Calling rcu_barrier() is not necessary here because the
644 * SCSI error handler guarantees that the function called by
645 * call_rcu() has been called before scsi_end_request() is
646 * called.
647 */
648 destroy_rcu_head(&cmd->rcu);
649
650 /*
651 * In the MQ case the command gets freed by __blk_mq_end_request,
652 * so we have to do all cleanup that depends on it earlier.
653 *
654 * We also can't kick the queues from irq context, so we
655 * will have to defer it to a workqueue.
656 */
657 scsi_mq_uninit_cmd(cmd);
658
659 /*
660 * queue is still alive, so grab the ref for preventing it
661 * from being cleaned up during running queue.
662 */
663 percpu_ref_get(&q->q_usage_counter);
664
665 __blk_mq_end_request(req, error);
666
667 scsi_run_queue_async(sdev);
668
669 percpu_ref_put(&q->q_usage_counter);
670 return false;
671}
672
673/**
674 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
675 * @result: scsi error code
676 *
677 * Translate a SCSI result code into a blk_status_t value.
678 */
679static blk_status_t scsi_result_to_blk_status(int result)
680{
681 /*
682 * Check the scsi-ml byte first in case we converted a host or status
683 * byte.
684 */
685 switch (scsi_ml_byte(result)) {
686 case SCSIML_STAT_OK:
687 break;
688 case SCSIML_STAT_RESV_CONFLICT:
689 return BLK_STS_RESV_CONFLICT;
690 case SCSIML_STAT_NOSPC:
691 return BLK_STS_NOSPC;
692 case SCSIML_STAT_MED_ERROR:
693 return BLK_STS_MEDIUM;
694 case SCSIML_STAT_TGT_FAILURE:
695 return BLK_STS_TARGET;
696 case SCSIML_STAT_DL_TIMEOUT:
697 return BLK_STS_DURATION_LIMIT;
698 }
699
700 switch (host_byte(result)) {
701 case DID_OK:
702 if (scsi_status_is_good(result))
703 return BLK_STS_OK;
704 return BLK_STS_IOERR;
705 case DID_TRANSPORT_FAILFAST:
706 case DID_TRANSPORT_MARGINAL:
707 return BLK_STS_TRANSPORT;
708 default:
709 return BLK_STS_IOERR;
710 }
711}
712
713/**
714 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
715 * @rq: request to examine
716 *
717 * Description:
718 * A request could be merge of IOs which require different failure
719 * handling. This function determines the number of bytes which
720 * can be failed from the beginning of the request without
721 * crossing into area which need to be retried further.
722 *
723 * Return:
724 * The number of bytes to fail.
725 */
726static unsigned int scsi_rq_err_bytes(const struct request *rq)
727{
728 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
729 unsigned int bytes = 0;
730 struct bio *bio;
731
732 if (!(rq->rq_flags & RQF_MIXED_MERGE))
733 return blk_rq_bytes(rq);
734
735 /*
736 * Currently the only 'mixing' which can happen is between
737 * different fastfail types. We can safely fail portions
738 * which have all the failfast bits that the first one has -
739 * the ones which are at least as eager to fail as the first
740 * one.
741 */
742 for (bio = rq->bio; bio; bio = bio->bi_next) {
743 if ((bio->bi_opf & ff) != ff)
744 break;
745 bytes += bio->bi_iter.bi_size;
746 }
747
748 /* this could lead to infinite loop */
749 BUG_ON(blk_rq_bytes(rq) && !bytes);
750 return bytes;
751}
752
753static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
754{
755 struct request *req = scsi_cmd_to_rq(cmd);
756 unsigned long wait_for;
757
758 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
759 return false;
760
761 wait_for = (cmd->allowed + 1) * req->timeout;
762 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
763 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
764 wait_for/HZ);
765 return true;
766 }
767 return false;
768}
769
770/*
771 * When ALUA transition state is returned, reprep the cmd to
772 * use the ALUA handler's transition timeout. Delay the reprep
773 * 1 sec to avoid aggressive retries of the target in that
774 * state.
775 */
776#define ALUA_TRANSITION_REPREP_DELAY 1000
777
778/* Helper for scsi_io_completion() when special action required. */
779static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
780{
781 struct request *req = scsi_cmd_to_rq(cmd);
782 int level = 0;
783 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
784 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
785 struct scsi_sense_hdr sshdr;
786 bool sense_valid;
787 bool sense_current = true; /* false implies "deferred sense" */
788 blk_status_t blk_stat;
789
790 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
791 if (sense_valid)
792 sense_current = !scsi_sense_is_deferred(&sshdr);
793
794 blk_stat = scsi_result_to_blk_status(result);
795
796 if (host_byte(result) == DID_RESET) {
797 /* Third party bus reset or reset for error recovery
798 * reasons. Just retry the command and see what
799 * happens.
800 */
801 action = ACTION_RETRY;
802 } else if (sense_valid && sense_current) {
803 switch (sshdr.sense_key) {
804 case UNIT_ATTENTION:
805 if (cmd->device->removable) {
806 /* Detected disc change. Set a bit
807 * and quietly refuse further access.
808 */
809 cmd->device->changed = 1;
810 action = ACTION_FAIL;
811 } else {
812 /* Must have been a power glitch, or a
813 * bus reset. Could not have been a
814 * media change, so we just retry the
815 * command and see what happens.
816 */
817 action = ACTION_RETRY;
818 }
819 break;
820 case ILLEGAL_REQUEST:
821 /* If we had an ILLEGAL REQUEST returned, then
822 * we may have performed an unsupported
823 * command. The only thing this should be
824 * would be a ten byte read where only a six
825 * byte read was supported. Also, on a system
826 * where READ CAPACITY failed, we may have
827 * read past the end of the disk.
828 */
829 if ((cmd->device->use_10_for_rw &&
830 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
831 (cmd->cmnd[0] == READ_10 ||
832 cmd->cmnd[0] == WRITE_10)) {
833 /* This will issue a new 6-byte command. */
834 cmd->device->use_10_for_rw = 0;
835 action = ACTION_REPREP;
836 } else if (sshdr.asc == 0x10) /* DIX */ {
837 action = ACTION_FAIL;
838 blk_stat = BLK_STS_PROTECTION;
839 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
840 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
841 action = ACTION_FAIL;
842 blk_stat = BLK_STS_TARGET;
843 } else
844 action = ACTION_FAIL;
845 break;
846 case ABORTED_COMMAND:
847 action = ACTION_FAIL;
848 if (sshdr.asc == 0x10) /* DIF */
849 blk_stat = BLK_STS_PROTECTION;
850 break;
851 case NOT_READY:
852 /* If the device is in the process of becoming
853 * ready, or has a temporary blockage, retry.
854 */
855 if (sshdr.asc == 0x04) {
856 switch (sshdr.ascq) {
857 case 0x01: /* becoming ready */
858 case 0x04: /* format in progress */
859 case 0x05: /* rebuild in progress */
860 case 0x06: /* recalculation in progress */
861 case 0x07: /* operation in progress */
862 case 0x08: /* Long write in progress */
863 case 0x09: /* self test in progress */
864 case 0x11: /* notify (enable spinup) required */
865 case 0x14: /* space allocation in progress */
866 case 0x1a: /* start stop unit in progress */
867 case 0x1b: /* sanitize in progress */
868 case 0x1d: /* configuration in progress */
869 case 0x24: /* depopulation in progress */
870 case 0x25: /* depopulation restore in progress */
871 action = ACTION_DELAYED_RETRY;
872 break;
873 case 0x0a: /* ALUA state transition */
874 action = ACTION_DELAYED_REPREP;
875 break;
876 default:
877 action = ACTION_FAIL;
878 break;
879 }
880 } else
881 action = ACTION_FAIL;
882 break;
883 case VOLUME_OVERFLOW:
884 /* See SSC3rXX or current. */
885 action = ACTION_FAIL;
886 break;
887 case DATA_PROTECT:
888 action = ACTION_FAIL;
889 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
890 (sshdr.asc == 0x55 &&
891 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
892 /* Insufficient zone resources */
893 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
894 }
895 break;
896 case COMPLETED:
897 fallthrough;
898 default:
899 action = ACTION_FAIL;
900 break;
901 }
902 } else
903 action = ACTION_FAIL;
904
905 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
906 action = ACTION_FAIL;
907
908 switch (action) {
909 case ACTION_FAIL:
910 /* Give up and fail the remainder of the request */
911 if (!(req->rq_flags & RQF_QUIET)) {
912 static DEFINE_RATELIMIT_STATE(_rs,
913 DEFAULT_RATELIMIT_INTERVAL,
914 DEFAULT_RATELIMIT_BURST);
915
916 if (unlikely(scsi_logging_level))
917 level =
918 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
919 SCSI_LOG_MLCOMPLETE_BITS);
920
921 /*
922 * if logging is enabled the failure will be printed
923 * in scsi_log_completion(), so avoid duplicate messages
924 */
925 if (!level && __ratelimit(&_rs)) {
926 scsi_print_result(cmd, NULL, FAILED);
927 if (sense_valid)
928 scsi_print_sense(cmd);
929 scsi_print_command(cmd);
930 }
931 }
932 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
933 return;
934 fallthrough;
935 case ACTION_REPREP:
936 scsi_mq_requeue_cmd(cmd, 0);
937 break;
938 case ACTION_DELAYED_REPREP:
939 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
940 break;
941 case ACTION_RETRY:
942 /* Retry the same command immediately */
943 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
944 break;
945 case ACTION_DELAYED_RETRY:
946 /* Retry the same command after a delay */
947 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
948 break;
949 }
950}
951
952/*
953 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
954 * new result that may suppress further error checking. Also modifies
955 * *blk_statp in some cases.
956 */
957static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
958 blk_status_t *blk_statp)
959{
960 bool sense_valid;
961 bool sense_current = true; /* false implies "deferred sense" */
962 struct request *req = scsi_cmd_to_rq(cmd);
963 struct scsi_sense_hdr sshdr;
964
965 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
966 if (sense_valid)
967 sense_current = !scsi_sense_is_deferred(&sshdr);
968
969 if (blk_rq_is_passthrough(req)) {
970 if (sense_valid) {
971 /*
972 * SG_IO wants current and deferred errors
973 */
974 cmd->sense_len = min(8 + cmd->sense_buffer[7],
975 SCSI_SENSE_BUFFERSIZE);
976 }
977 if (sense_current)
978 *blk_statp = scsi_result_to_blk_status(result);
979 } else if (blk_rq_bytes(req) == 0 && sense_current) {
980 /*
981 * Flush commands do not transfers any data, and thus cannot use
982 * good_bytes != blk_rq_bytes(req) as the signal for an error.
983 * This sets *blk_statp explicitly for the problem case.
984 */
985 *blk_statp = scsi_result_to_blk_status(result);
986 }
987 /*
988 * Recovered errors need reporting, but they're always treated as
989 * success, so fiddle the result code here. For passthrough requests
990 * we already took a copy of the original into sreq->result which
991 * is what gets returned to the user
992 */
993 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
994 bool do_print = true;
995 /*
996 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
997 * skip print since caller wants ATA registers. Only occurs
998 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
999 */
1000 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
1001 do_print = false;
1002 else if (req->rq_flags & RQF_QUIET)
1003 do_print = false;
1004 if (do_print)
1005 scsi_print_sense(cmd);
1006 result = 0;
1007 /* for passthrough, *blk_statp may be set */
1008 *blk_statp = BLK_STS_OK;
1009 }
1010 /*
1011 * Another corner case: the SCSI status byte is non-zero but 'good'.
1012 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
1013 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
1014 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
1015 * intermediate statuses (both obsolete in SAM-4) as good.
1016 */
1017 if ((result & 0xff) && scsi_status_is_good(result)) {
1018 result = 0;
1019 *blk_statp = BLK_STS_OK;
1020 }
1021 return result;
1022}
1023
1024/**
1025 * scsi_io_completion - Completion processing for SCSI commands.
1026 * @cmd: command that is finished.
1027 * @good_bytes: number of processed bytes.
1028 *
1029 * We will finish off the specified number of sectors. If we are done, the
1030 * command block will be released and the queue function will be goosed. If we
1031 * are not done then we have to figure out what to do next:
1032 *
1033 * a) We can call scsi_mq_requeue_cmd(). The request will be
1034 * unprepared and put back on the queue. Then a new command will
1035 * be created for it. This should be used if we made forward
1036 * progress, or if we want to switch from READ(10) to READ(6) for
1037 * example.
1038 *
1039 * b) We can call scsi_io_completion_action(). The request will be
1040 * put back on the queue and retried using the same command as
1041 * before, possibly after a delay.
1042 *
1043 * c) We can call scsi_end_request() with blk_stat other than
1044 * BLK_STS_OK, to fail the remainder of the request.
1045 */
1046void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
1047{
1048 int result = cmd->result;
1049 struct request *req = scsi_cmd_to_rq(cmd);
1050 blk_status_t blk_stat = BLK_STS_OK;
1051
1052 if (unlikely(result)) /* a nz result may or may not be an error */
1053 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
1054
1055 /*
1056 * Next deal with any sectors which we were able to correctly
1057 * handle.
1058 */
1059 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
1060 "%u sectors total, %d bytes done.\n",
1061 blk_rq_sectors(req), good_bytes));
1062
1063 /*
1064 * Failed, zero length commands always need to drop down
1065 * to retry code. Fast path should return in this block.
1066 */
1067 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
1068 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
1069 return; /* no bytes remaining */
1070 }
1071
1072 /* Kill remainder if no retries. */
1073 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
1074 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
1075 WARN_ONCE(true,
1076 "Bytes remaining after failed, no-retry command");
1077 return;
1078 }
1079
1080 /*
1081 * If there had been no error, but we have leftover bytes in the
1082 * request just queue the command up again.
1083 */
1084 if (likely(result == 0))
1085 scsi_mq_requeue_cmd(cmd, 0);
1086 else
1087 scsi_io_completion_action(cmd, result);
1088}
1089
1090static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1091 struct request *rq)
1092{
1093 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1094 !op_is_write(req_op(rq)) &&
1095 sdev->host->hostt->dma_need_drain(rq);
1096}
1097
1098/**
1099 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1100 * @cmd: SCSI command data structure to initialize.
1101 *
1102 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1103 * for @cmd.
1104 *
1105 * Returns:
1106 * * BLK_STS_OK - on success
1107 * * BLK_STS_RESOURCE - if the failure is retryable
1108 * * BLK_STS_IOERR - if the failure is fatal
1109 */
1110blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1111{
1112 struct scsi_device *sdev = cmd->device;
1113 struct request *rq = scsi_cmd_to_rq(cmd);
1114 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1115 struct scatterlist *last_sg = NULL;
1116 blk_status_t ret;
1117 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1118 int count;
1119
1120 if (WARN_ON_ONCE(!nr_segs))
1121 return BLK_STS_IOERR;
1122
1123 /*
1124 * Make sure there is space for the drain. The driver must adjust
1125 * max_hw_segments to be prepared for this.
1126 */
1127 if (need_drain)
1128 nr_segs++;
1129
1130 /*
1131 * If sg table allocation fails, requeue request later.
1132 */
1133 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1134 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1135 return BLK_STS_RESOURCE;
1136
1137 /*
1138 * Next, walk the list, and fill in the addresses and sizes of
1139 * each segment.
1140 */
1141 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1142
1143 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1144 unsigned int pad_len =
1145 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1146
1147 last_sg->length += pad_len;
1148 cmd->extra_len += pad_len;
1149 }
1150
1151 if (need_drain) {
1152 sg_unmark_end(last_sg);
1153 last_sg = sg_next(last_sg);
1154 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1155 sg_mark_end(last_sg);
1156
1157 cmd->extra_len += sdev->dma_drain_len;
1158 count++;
1159 }
1160
1161 BUG_ON(count > cmd->sdb.table.nents);
1162 cmd->sdb.table.nents = count;
1163 cmd->sdb.length = blk_rq_payload_bytes(rq);
1164
1165 if (blk_integrity_rq(rq)) {
1166 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1167 int ivecs;
1168
1169 if (WARN_ON_ONCE(!prot_sdb)) {
1170 /*
1171 * This can happen if someone (e.g. multipath)
1172 * queues a command to a device on an adapter
1173 * that does not support DIX.
1174 */
1175 ret = BLK_STS_IOERR;
1176 goto out_free_sgtables;
1177 }
1178
1179 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1180
1181 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1182 prot_sdb->table.sgl,
1183 SCSI_INLINE_PROT_SG_CNT)) {
1184 ret = BLK_STS_RESOURCE;
1185 goto out_free_sgtables;
1186 }
1187
1188 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1189 prot_sdb->table.sgl);
1190 BUG_ON(count > ivecs);
1191 BUG_ON(count > queue_max_integrity_segments(rq->q));
1192
1193 cmd->prot_sdb = prot_sdb;
1194 cmd->prot_sdb->table.nents = count;
1195 }
1196
1197 return BLK_STS_OK;
1198out_free_sgtables:
1199 scsi_free_sgtables(cmd);
1200 return ret;
1201}
1202EXPORT_SYMBOL(scsi_alloc_sgtables);
1203
1204/**
1205 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1206 * @rq: Request associated with the SCSI command to be initialized.
1207 *
1208 * This function initializes the members of struct scsi_cmnd that must be
1209 * initialized before request processing starts and that won't be
1210 * reinitialized if a SCSI command is requeued.
1211 */
1212static void scsi_initialize_rq(struct request *rq)
1213{
1214 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1215
1216 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1217 cmd->cmd_len = MAX_COMMAND_SIZE;
1218 cmd->sense_len = 0;
1219 init_rcu_head(&cmd->rcu);
1220 cmd->jiffies_at_alloc = jiffies;
1221 cmd->retries = 0;
1222}
1223
1224struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1225 blk_mq_req_flags_t flags)
1226{
1227 struct request *rq;
1228
1229 rq = blk_mq_alloc_request(q, opf, flags);
1230 if (!IS_ERR(rq))
1231 scsi_initialize_rq(rq);
1232 return rq;
1233}
1234EXPORT_SYMBOL_GPL(scsi_alloc_request);
1235
1236/*
1237 * Only called when the request isn't completed by SCSI, and not freed by
1238 * SCSI
1239 */
1240static void scsi_cleanup_rq(struct request *rq)
1241{
1242 if (rq->rq_flags & RQF_DONTPREP) {
1243 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1244 rq->rq_flags &= ~RQF_DONTPREP;
1245 }
1246}
1247
1248/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1249void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1250{
1251 struct request *rq = scsi_cmd_to_rq(cmd);
1252
1253 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1254 cmd->flags |= SCMD_INITIALIZED;
1255 scsi_initialize_rq(rq);
1256 }
1257
1258 cmd->device = dev;
1259 INIT_LIST_HEAD(&cmd->eh_entry);
1260 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1261}
1262
1263static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1264 struct request *req)
1265{
1266 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1267
1268 /*
1269 * Passthrough requests may transfer data, in which case they must
1270 * a bio attached to them. Or they might contain a SCSI command
1271 * that does not transfer data, in which case they may optionally
1272 * submit a request without an attached bio.
1273 */
1274 if (req->bio) {
1275 blk_status_t ret = scsi_alloc_sgtables(cmd);
1276 if (unlikely(ret != BLK_STS_OK))
1277 return ret;
1278 } else {
1279 BUG_ON(blk_rq_bytes(req));
1280
1281 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1282 }
1283
1284 cmd->transfersize = blk_rq_bytes(req);
1285 return BLK_STS_OK;
1286}
1287
1288static blk_status_t
1289scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1290{
1291 switch (sdev->sdev_state) {
1292 case SDEV_CREATED:
1293 return BLK_STS_OK;
1294 case SDEV_OFFLINE:
1295 case SDEV_TRANSPORT_OFFLINE:
1296 /*
1297 * If the device is offline we refuse to process any
1298 * commands. The device must be brought online
1299 * before trying any recovery commands.
1300 */
1301 if (!sdev->offline_already) {
1302 sdev->offline_already = true;
1303 sdev_printk(KERN_ERR, sdev,
1304 "rejecting I/O to offline device\n");
1305 }
1306 return BLK_STS_IOERR;
1307 case SDEV_DEL:
1308 /*
1309 * If the device is fully deleted, we refuse to
1310 * process any commands as well.
1311 */
1312 sdev_printk(KERN_ERR, sdev,
1313 "rejecting I/O to dead device\n");
1314 return BLK_STS_IOERR;
1315 case SDEV_BLOCK:
1316 case SDEV_CREATED_BLOCK:
1317 return BLK_STS_RESOURCE;
1318 case SDEV_QUIESCE:
1319 /*
1320 * If the device is blocked we only accept power management
1321 * commands.
1322 */
1323 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1324 return BLK_STS_RESOURCE;
1325 return BLK_STS_OK;
1326 default:
1327 /*
1328 * For any other not fully online state we only allow
1329 * power management commands.
1330 */
1331 if (req && !(req->rq_flags & RQF_PM))
1332 return BLK_STS_OFFLINE;
1333 return BLK_STS_OK;
1334 }
1335}
1336
1337/*
1338 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1339 * and return the token else return -1.
1340 */
1341static inline int scsi_dev_queue_ready(struct request_queue *q,
1342 struct scsi_device *sdev)
1343{
1344 int token;
1345
1346 token = sbitmap_get(&sdev->budget_map);
1347 if (token < 0)
1348 return -1;
1349
1350 if (!atomic_read(&sdev->device_blocked))
1351 return token;
1352
1353 /*
1354 * Only unblock if no other commands are pending and
1355 * if device_blocked has decreased to zero
1356 */
1357 if (scsi_device_busy(sdev) > 1 ||
1358 atomic_dec_return(&sdev->device_blocked) > 0) {
1359 sbitmap_put(&sdev->budget_map, token);
1360 return -1;
1361 }
1362
1363 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1364 "unblocking device at zero depth\n"));
1365
1366 return token;
1367}
1368
1369/*
1370 * scsi_target_queue_ready: checks if there we can send commands to target
1371 * @sdev: scsi device on starget to check.
1372 */
1373static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1374 struct scsi_device *sdev)
1375{
1376 struct scsi_target *starget = scsi_target(sdev);
1377 unsigned int busy;
1378
1379 if (starget->single_lun) {
1380 spin_lock_irq(shost->host_lock);
1381 if (starget->starget_sdev_user &&
1382 starget->starget_sdev_user != sdev) {
1383 spin_unlock_irq(shost->host_lock);
1384 return 0;
1385 }
1386 starget->starget_sdev_user = sdev;
1387 spin_unlock_irq(shost->host_lock);
1388 }
1389
1390 if (starget->can_queue <= 0)
1391 return 1;
1392
1393 busy = atomic_inc_return(&starget->target_busy) - 1;
1394 if (atomic_read(&starget->target_blocked) > 0) {
1395 if (busy)
1396 goto starved;
1397
1398 /*
1399 * unblock after target_blocked iterates to zero
1400 */
1401 if (atomic_dec_return(&starget->target_blocked) > 0)
1402 goto out_dec;
1403
1404 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1405 "unblocking target at zero depth\n"));
1406 }
1407
1408 if (busy >= starget->can_queue)
1409 goto starved;
1410
1411 return 1;
1412
1413starved:
1414 spin_lock_irq(shost->host_lock);
1415 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1416 spin_unlock_irq(shost->host_lock);
1417out_dec:
1418 if (starget->can_queue > 0)
1419 atomic_dec(&starget->target_busy);
1420 return 0;
1421}
1422
1423/*
1424 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1425 * return 0. We must end up running the queue again whenever 0 is
1426 * returned, else IO can hang.
1427 */
1428static inline int scsi_host_queue_ready(struct request_queue *q,
1429 struct Scsi_Host *shost,
1430 struct scsi_device *sdev,
1431 struct scsi_cmnd *cmd)
1432{
1433 if (atomic_read(&shost->host_blocked) > 0) {
1434 if (scsi_host_busy(shost) > 0)
1435 goto starved;
1436
1437 /*
1438 * unblock after host_blocked iterates to zero
1439 */
1440 if (atomic_dec_return(&shost->host_blocked) > 0)
1441 goto out_dec;
1442
1443 SCSI_LOG_MLQUEUE(3,
1444 shost_printk(KERN_INFO, shost,
1445 "unblocking host at zero depth\n"));
1446 }
1447
1448 if (shost->host_self_blocked)
1449 goto starved;
1450
1451 /* We're OK to process the command, so we can't be starved */
1452 if (!list_empty(&sdev->starved_entry)) {
1453 spin_lock_irq(shost->host_lock);
1454 if (!list_empty(&sdev->starved_entry))
1455 list_del_init(&sdev->starved_entry);
1456 spin_unlock_irq(shost->host_lock);
1457 }
1458
1459 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1460
1461 return 1;
1462
1463starved:
1464 spin_lock_irq(shost->host_lock);
1465 if (list_empty(&sdev->starved_entry))
1466 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1467 spin_unlock_irq(shost->host_lock);
1468out_dec:
1469 scsi_dec_host_busy(shost, cmd);
1470 return 0;
1471}
1472
1473/*
1474 * Busy state exporting function for request stacking drivers.
1475 *
1476 * For efficiency, no lock is taken to check the busy state of
1477 * shost/starget/sdev, since the returned value is not guaranteed and
1478 * may be changed after request stacking drivers call the function,
1479 * regardless of taking lock or not.
1480 *
1481 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1482 * needs to return 'not busy'. Otherwise, request stacking drivers
1483 * may hold requests forever.
1484 */
1485static bool scsi_mq_lld_busy(struct request_queue *q)
1486{
1487 struct scsi_device *sdev = q->queuedata;
1488 struct Scsi_Host *shost;
1489
1490 if (blk_queue_dying(q))
1491 return false;
1492
1493 shost = sdev->host;
1494
1495 /*
1496 * Ignore host/starget busy state.
1497 * Since block layer does not have a concept of fairness across
1498 * multiple queues, congestion of host/starget needs to be handled
1499 * in SCSI layer.
1500 */
1501 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1502 return true;
1503
1504 return false;
1505}
1506
1507/*
1508 * Block layer request completion callback. May be called from interrupt
1509 * context.
1510 */
1511static void scsi_complete(struct request *rq)
1512{
1513 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1514 enum scsi_disposition disposition;
1515
1516 INIT_LIST_HEAD(&cmd->eh_entry);
1517
1518 atomic_inc(&cmd->device->iodone_cnt);
1519 if (cmd->result)
1520 atomic_inc(&cmd->device->ioerr_cnt);
1521
1522 disposition = scsi_decide_disposition(cmd);
1523 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1524 disposition = SUCCESS;
1525
1526 scsi_log_completion(cmd, disposition);
1527
1528 switch (disposition) {
1529 case SUCCESS:
1530 scsi_finish_command(cmd);
1531 break;
1532 case NEEDS_RETRY:
1533 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1534 break;
1535 case ADD_TO_MLQUEUE:
1536 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1537 break;
1538 default:
1539 scsi_eh_scmd_add(cmd);
1540 break;
1541 }
1542}
1543
1544/**
1545 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1546 * @cmd: command block we are dispatching.
1547 *
1548 * Return: nonzero return request was rejected and device's queue needs to be
1549 * plugged.
1550 */
1551static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1552{
1553 struct Scsi_Host *host = cmd->device->host;
1554 int rtn = 0;
1555
1556 atomic_inc(&cmd->device->iorequest_cnt);
1557
1558 /* check if the device is still usable */
1559 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1560 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1561 * returns an immediate error upwards, and signals
1562 * that the device is no longer present */
1563 cmd->result = DID_NO_CONNECT << 16;
1564 goto done;
1565 }
1566
1567 /* Check to see if the scsi lld made this device blocked. */
1568 if (unlikely(scsi_device_blocked(cmd->device))) {
1569 /*
1570 * in blocked state, the command is just put back on
1571 * the device queue. The suspend state has already
1572 * blocked the queue so future requests should not
1573 * occur until the device transitions out of the
1574 * suspend state.
1575 */
1576 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1577 "queuecommand : device blocked\n"));
1578 atomic_dec(&cmd->device->iorequest_cnt);
1579 return SCSI_MLQUEUE_DEVICE_BUSY;
1580 }
1581
1582 /* Store the LUN value in cmnd, if needed. */
1583 if (cmd->device->lun_in_cdb)
1584 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1585 (cmd->device->lun << 5 & 0xe0);
1586
1587 scsi_log_send(cmd);
1588
1589 /*
1590 * Before we queue this command, check if the command
1591 * length exceeds what the host adapter can handle.
1592 */
1593 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1594 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1595 "queuecommand : command too long. "
1596 "cdb_size=%d host->max_cmd_len=%d\n",
1597 cmd->cmd_len, cmd->device->host->max_cmd_len));
1598 cmd->result = (DID_ABORT << 16);
1599 goto done;
1600 }
1601
1602 if (unlikely(host->shost_state == SHOST_DEL)) {
1603 cmd->result = (DID_NO_CONNECT << 16);
1604 goto done;
1605
1606 }
1607
1608 trace_scsi_dispatch_cmd_start(cmd);
1609 rtn = host->hostt->queuecommand(host, cmd);
1610 if (rtn) {
1611 atomic_dec(&cmd->device->iorequest_cnt);
1612 trace_scsi_dispatch_cmd_error(cmd, rtn);
1613 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1614 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1615 rtn = SCSI_MLQUEUE_HOST_BUSY;
1616
1617 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1618 "queuecommand : request rejected\n"));
1619 }
1620
1621 return rtn;
1622 done:
1623 scsi_done(cmd);
1624 return 0;
1625}
1626
1627/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1628static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1629{
1630 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1631 sizeof(struct scatterlist);
1632}
1633
1634static blk_status_t scsi_prepare_cmd(struct request *req)
1635{
1636 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1637 struct scsi_device *sdev = req->q->queuedata;
1638 struct Scsi_Host *shost = sdev->host;
1639 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1640 struct scatterlist *sg;
1641
1642 scsi_init_command(sdev, cmd);
1643
1644 cmd->eh_eflags = 0;
1645 cmd->prot_type = 0;
1646 cmd->prot_flags = 0;
1647 cmd->submitter = 0;
1648 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1649 cmd->underflow = 0;
1650 cmd->transfersize = 0;
1651 cmd->host_scribble = NULL;
1652 cmd->result = 0;
1653 cmd->extra_len = 0;
1654 cmd->state = 0;
1655 if (in_flight)
1656 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1657
1658 /*
1659 * Only clear the driver-private command data if the LLD does not supply
1660 * a function to initialize that data.
1661 */
1662 if (!shost->hostt->init_cmd_priv)
1663 memset(cmd + 1, 0, shost->hostt->cmd_size);
1664
1665 cmd->prot_op = SCSI_PROT_NORMAL;
1666 if (blk_rq_bytes(req))
1667 cmd->sc_data_direction = rq_dma_dir(req);
1668 else
1669 cmd->sc_data_direction = DMA_NONE;
1670
1671 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1672 cmd->sdb.table.sgl = sg;
1673
1674 if (scsi_host_get_prot(shost)) {
1675 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1676
1677 cmd->prot_sdb->table.sgl =
1678 (struct scatterlist *)(cmd->prot_sdb + 1);
1679 }
1680
1681 /*
1682 * Special handling for passthrough commands, which don't go to the ULP
1683 * at all:
1684 */
1685 if (blk_rq_is_passthrough(req))
1686 return scsi_setup_scsi_cmnd(sdev, req);
1687
1688 if (sdev->handler && sdev->handler->prep_fn) {
1689 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1690
1691 if (ret != BLK_STS_OK)
1692 return ret;
1693 }
1694
1695 /* Usually overridden by the ULP */
1696 cmd->allowed = 0;
1697 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1698 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1699}
1700
1701static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1702{
1703 struct request *req = scsi_cmd_to_rq(cmd);
1704
1705 switch (cmd->submitter) {
1706 case SUBMITTED_BY_BLOCK_LAYER:
1707 break;
1708 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1709 return scsi_eh_done(cmd);
1710 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1711 return;
1712 }
1713
1714 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1715 return;
1716 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1717 return;
1718 trace_scsi_dispatch_cmd_done(cmd);
1719
1720 if (complete_directly)
1721 blk_mq_complete_request_direct(req, scsi_complete);
1722 else
1723 blk_mq_complete_request(req);
1724}
1725
1726void scsi_done(struct scsi_cmnd *cmd)
1727{
1728 scsi_done_internal(cmd, false);
1729}
1730EXPORT_SYMBOL(scsi_done);
1731
1732void scsi_done_direct(struct scsi_cmnd *cmd)
1733{
1734 scsi_done_internal(cmd, true);
1735}
1736EXPORT_SYMBOL(scsi_done_direct);
1737
1738static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1739{
1740 struct scsi_device *sdev = q->queuedata;
1741
1742 sbitmap_put(&sdev->budget_map, budget_token);
1743}
1744
1745/*
1746 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1747 * not change behaviour from the previous unplug mechanism, experimentation
1748 * may prove this needs changing.
1749 */
1750#define SCSI_QUEUE_DELAY 3
1751
1752static int scsi_mq_get_budget(struct request_queue *q)
1753{
1754 struct scsi_device *sdev = q->queuedata;
1755 int token = scsi_dev_queue_ready(q, sdev);
1756
1757 if (token >= 0)
1758 return token;
1759
1760 atomic_inc(&sdev->restarts);
1761
1762 /*
1763 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1764 * .restarts must be incremented before .device_busy is read because the
1765 * code in scsi_run_queue_async() depends on the order of these operations.
1766 */
1767 smp_mb__after_atomic();
1768
1769 /*
1770 * If all in-flight requests originated from this LUN are completed
1771 * before reading .device_busy, sdev->device_busy will be observed as
1772 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1773 * soon. Otherwise, completion of one of these requests will observe
1774 * the .restarts flag, and the request queue will be run for handling
1775 * this request, see scsi_end_request().
1776 */
1777 if (unlikely(scsi_device_busy(sdev) == 0 &&
1778 !scsi_device_blocked(sdev)))
1779 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1780 return -1;
1781}
1782
1783static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1784{
1785 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1786
1787 cmd->budget_token = token;
1788}
1789
1790static int scsi_mq_get_rq_budget_token(struct request *req)
1791{
1792 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1793
1794 return cmd->budget_token;
1795}
1796
1797static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1798 const struct blk_mq_queue_data *bd)
1799{
1800 struct request *req = bd->rq;
1801 struct request_queue *q = req->q;
1802 struct scsi_device *sdev = q->queuedata;
1803 struct Scsi_Host *shost = sdev->host;
1804 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1805 blk_status_t ret;
1806 int reason;
1807
1808 WARN_ON_ONCE(cmd->budget_token < 0);
1809
1810 /*
1811 * If the device is not in running state we will reject some or all
1812 * commands.
1813 */
1814 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1815 ret = scsi_device_state_check(sdev, req);
1816 if (ret != BLK_STS_OK)
1817 goto out_put_budget;
1818 }
1819
1820 ret = BLK_STS_RESOURCE;
1821 if (!scsi_target_queue_ready(shost, sdev))
1822 goto out_put_budget;
1823 if (unlikely(scsi_host_in_recovery(shost))) {
1824 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1825 ret = BLK_STS_OFFLINE;
1826 goto out_dec_target_busy;
1827 }
1828 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1829 goto out_dec_target_busy;
1830
1831 if (!(req->rq_flags & RQF_DONTPREP)) {
1832 ret = scsi_prepare_cmd(req);
1833 if (ret != BLK_STS_OK)
1834 goto out_dec_host_busy;
1835 req->rq_flags |= RQF_DONTPREP;
1836 } else {
1837 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1838 }
1839
1840 cmd->flags &= SCMD_PRESERVED_FLAGS;
1841 if (sdev->simple_tags)
1842 cmd->flags |= SCMD_TAGGED;
1843 if (bd->last)
1844 cmd->flags |= SCMD_LAST;
1845
1846 scsi_set_resid(cmd, 0);
1847 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1848 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1849
1850 blk_mq_start_request(req);
1851 reason = scsi_dispatch_cmd(cmd);
1852 if (reason) {
1853 scsi_set_blocked(cmd, reason);
1854 ret = BLK_STS_RESOURCE;
1855 goto out_dec_host_busy;
1856 }
1857
1858 return BLK_STS_OK;
1859
1860out_dec_host_busy:
1861 scsi_dec_host_busy(shost, cmd);
1862out_dec_target_busy:
1863 if (scsi_target(sdev)->can_queue > 0)
1864 atomic_dec(&scsi_target(sdev)->target_busy);
1865out_put_budget:
1866 scsi_mq_put_budget(q, cmd->budget_token);
1867 cmd->budget_token = -1;
1868 switch (ret) {
1869 case BLK_STS_OK:
1870 break;
1871 case BLK_STS_RESOURCE:
1872 case BLK_STS_ZONE_RESOURCE:
1873 if (scsi_device_blocked(sdev))
1874 ret = BLK_STS_DEV_RESOURCE;
1875 break;
1876 case BLK_STS_AGAIN:
1877 cmd->result = DID_BUS_BUSY << 16;
1878 if (req->rq_flags & RQF_DONTPREP)
1879 scsi_mq_uninit_cmd(cmd);
1880 break;
1881 default:
1882 if (unlikely(!scsi_device_online(sdev)))
1883 cmd->result = DID_NO_CONNECT << 16;
1884 else
1885 cmd->result = DID_ERROR << 16;
1886 /*
1887 * Make sure to release all allocated resources when
1888 * we hit an error, as we will never see this command
1889 * again.
1890 */
1891 if (req->rq_flags & RQF_DONTPREP)
1892 scsi_mq_uninit_cmd(cmd);
1893 scsi_run_queue_async(sdev);
1894 break;
1895 }
1896 return ret;
1897}
1898
1899static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1900 unsigned int hctx_idx, unsigned int numa_node)
1901{
1902 struct Scsi_Host *shost = set->driver_data;
1903 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1904 struct scatterlist *sg;
1905 int ret = 0;
1906
1907 cmd->sense_buffer =
1908 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1909 if (!cmd->sense_buffer)
1910 return -ENOMEM;
1911
1912 if (scsi_host_get_prot(shost)) {
1913 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1914 shost->hostt->cmd_size;
1915 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1916 }
1917
1918 if (shost->hostt->init_cmd_priv) {
1919 ret = shost->hostt->init_cmd_priv(shost, cmd);
1920 if (ret < 0)
1921 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1922 }
1923
1924 return ret;
1925}
1926
1927static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1928 unsigned int hctx_idx)
1929{
1930 struct Scsi_Host *shost = set->driver_data;
1931 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1932
1933 if (shost->hostt->exit_cmd_priv)
1934 shost->hostt->exit_cmd_priv(shost, cmd);
1935 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1936}
1937
1938
1939static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1940{
1941 struct Scsi_Host *shost = hctx->driver_data;
1942
1943 if (shost->hostt->mq_poll)
1944 return shost->hostt->mq_poll(shost, hctx->queue_num);
1945
1946 return 0;
1947}
1948
1949static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1950 unsigned int hctx_idx)
1951{
1952 struct Scsi_Host *shost = data;
1953
1954 hctx->driver_data = shost;
1955 return 0;
1956}
1957
1958static void scsi_map_queues(struct blk_mq_tag_set *set)
1959{
1960 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1961
1962 if (shost->hostt->map_queues)
1963 return shost->hostt->map_queues(shost);
1964 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1965}
1966
1967void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1968{
1969 struct device *dev = shost->dma_dev;
1970
1971 /*
1972 * this limit is imposed by hardware restrictions
1973 */
1974 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1975 SG_MAX_SEGMENTS));
1976
1977 if (scsi_host_prot_dma(shost)) {
1978 shost->sg_prot_tablesize =
1979 min_not_zero(shost->sg_prot_tablesize,
1980 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1981 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1982 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1983 }
1984
1985 blk_queue_max_hw_sectors(q, shost->max_sectors);
1986 blk_queue_segment_boundary(q, shost->dma_boundary);
1987 dma_set_seg_boundary(dev, shost->dma_boundary);
1988
1989 blk_queue_max_segment_size(q, shost->max_segment_size);
1990 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1991 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1992
1993 /*
1994 * Set a reasonable default alignment: The larger of 32-byte (dword),
1995 * which is a common minimum for HBAs, and the minimum DMA alignment,
1996 * which is set by the platform.
1997 *
1998 * Devices that require a bigger alignment can increase it later.
1999 */
2000 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
2001}
2002EXPORT_SYMBOL_GPL(__scsi_init_queue);
2003
2004static const struct blk_mq_ops scsi_mq_ops_no_commit = {
2005 .get_budget = scsi_mq_get_budget,
2006 .put_budget = scsi_mq_put_budget,
2007 .queue_rq = scsi_queue_rq,
2008 .complete = scsi_complete,
2009 .timeout = scsi_timeout,
2010#ifdef CONFIG_BLK_DEBUG_FS
2011 .show_rq = scsi_show_rq,
2012#endif
2013 .init_request = scsi_mq_init_request,
2014 .exit_request = scsi_mq_exit_request,
2015 .cleanup_rq = scsi_cleanup_rq,
2016 .busy = scsi_mq_lld_busy,
2017 .map_queues = scsi_map_queues,
2018 .init_hctx = scsi_init_hctx,
2019 .poll = scsi_mq_poll,
2020 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2021 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2022};
2023
2024
2025static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
2026{
2027 struct Scsi_Host *shost = hctx->driver_data;
2028
2029 shost->hostt->commit_rqs(shost, hctx->queue_num);
2030}
2031
2032static const struct blk_mq_ops scsi_mq_ops = {
2033 .get_budget = scsi_mq_get_budget,
2034 .put_budget = scsi_mq_put_budget,
2035 .queue_rq = scsi_queue_rq,
2036 .commit_rqs = scsi_commit_rqs,
2037 .complete = scsi_complete,
2038 .timeout = scsi_timeout,
2039#ifdef CONFIG_BLK_DEBUG_FS
2040 .show_rq = scsi_show_rq,
2041#endif
2042 .init_request = scsi_mq_init_request,
2043 .exit_request = scsi_mq_exit_request,
2044 .cleanup_rq = scsi_cleanup_rq,
2045 .busy = scsi_mq_lld_busy,
2046 .map_queues = scsi_map_queues,
2047 .init_hctx = scsi_init_hctx,
2048 .poll = scsi_mq_poll,
2049 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2050 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2051};
2052
2053int scsi_mq_setup_tags(struct Scsi_Host *shost)
2054{
2055 unsigned int cmd_size, sgl_size;
2056 struct blk_mq_tag_set *tag_set = &shost->tag_set;
2057
2058 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
2059 scsi_mq_inline_sgl_size(shost));
2060 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2061 if (scsi_host_get_prot(shost))
2062 cmd_size += sizeof(struct scsi_data_buffer) +
2063 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
2064
2065 memset(tag_set, 0, sizeof(*tag_set));
2066 if (shost->hostt->commit_rqs)
2067 tag_set->ops = &scsi_mq_ops;
2068 else
2069 tag_set->ops = &scsi_mq_ops_no_commit;
2070 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
2071 tag_set->nr_maps = shost->nr_maps ? : 1;
2072 tag_set->queue_depth = shost->can_queue;
2073 tag_set->cmd_size = cmd_size;
2074 tag_set->numa_node = dev_to_node(shost->dma_dev);
2075 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
2076 tag_set->flags |=
2077 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2078 if (shost->queuecommand_may_block)
2079 tag_set->flags |= BLK_MQ_F_BLOCKING;
2080 tag_set->driver_data = shost;
2081 if (shost->host_tagset)
2082 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
2083
2084 return blk_mq_alloc_tag_set(tag_set);
2085}
2086
2087void scsi_mq_free_tags(struct kref *kref)
2088{
2089 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
2090 tagset_refcnt);
2091
2092 blk_mq_free_tag_set(&shost->tag_set);
2093 complete(&shost->tagset_freed);
2094}
2095
2096/**
2097 * scsi_device_from_queue - return sdev associated with a request_queue
2098 * @q: The request queue to return the sdev from
2099 *
2100 * Return the sdev associated with a request queue or NULL if the
2101 * request_queue does not reference a SCSI device.
2102 */
2103struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2104{
2105 struct scsi_device *sdev = NULL;
2106
2107 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2108 q->mq_ops == &scsi_mq_ops)
2109 sdev = q->queuedata;
2110 if (!sdev || !get_device(&sdev->sdev_gendev))
2111 sdev = NULL;
2112
2113 return sdev;
2114}
2115/*
2116 * pktcdvd should have been integrated into the SCSI layers, but for historical
2117 * reasons like the old IDE driver it isn't. This export allows it to safely
2118 * probe if a given device is a SCSI one and only attach to that.
2119 */
2120#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2121EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2122#endif
2123
2124/**
2125 * scsi_block_requests - Utility function used by low-level drivers to prevent
2126 * further commands from being queued to the device.
2127 * @shost: host in question
2128 *
2129 * There is no timer nor any other means by which the requests get unblocked
2130 * other than the low-level driver calling scsi_unblock_requests().
2131 */
2132void scsi_block_requests(struct Scsi_Host *shost)
2133{
2134 shost->host_self_blocked = 1;
2135}
2136EXPORT_SYMBOL(scsi_block_requests);
2137
2138/**
2139 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2140 * further commands to be queued to the device.
2141 * @shost: host in question
2142 *
2143 * There is no timer nor any other means by which the requests get unblocked
2144 * other than the low-level driver calling scsi_unblock_requests(). This is done
2145 * as an API function so that changes to the internals of the scsi mid-layer
2146 * won't require wholesale changes to drivers that use this feature.
2147 */
2148void scsi_unblock_requests(struct Scsi_Host *shost)
2149{
2150 shost->host_self_blocked = 0;
2151 scsi_run_host_queues(shost);
2152}
2153EXPORT_SYMBOL(scsi_unblock_requests);
2154
2155void scsi_exit_queue(void)
2156{
2157 kmem_cache_destroy(scsi_sense_cache);
2158}
2159
2160/**
2161 * scsi_mode_select - issue a mode select
2162 * @sdev: SCSI device to be queried
2163 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2164 * @sp: Save page bit (0 == don't save, 1 == save)
2165 * @buffer: request buffer (may not be smaller than eight bytes)
2166 * @len: length of request buffer.
2167 * @timeout: command timeout
2168 * @retries: number of retries before failing
2169 * @data: returns a structure abstracting the mode header data
2170 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2171 * must be SCSI_SENSE_BUFFERSIZE big.
2172 *
2173 * Returns zero if successful; negative error number or scsi
2174 * status on error
2175 *
2176 */
2177int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2178 unsigned char *buffer, int len, int timeout, int retries,
2179 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2180{
2181 unsigned char cmd[10];
2182 unsigned char *real_buffer;
2183 const struct scsi_exec_args exec_args = {
2184 .sshdr = sshdr,
2185 };
2186 int ret;
2187
2188 memset(cmd, 0, sizeof(cmd));
2189 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2190
2191 /*
2192 * Use MODE SELECT(10) if the device asked for it or if the mode page
2193 * and the mode select header cannot fit within the maximumm 255 bytes
2194 * of the MODE SELECT(6) command.
2195 */
2196 if (sdev->use_10_for_ms ||
2197 len + 4 > 255 ||
2198 data->block_descriptor_length > 255) {
2199 if (len > 65535 - 8)
2200 return -EINVAL;
2201 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2202 if (!real_buffer)
2203 return -ENOMEM;
2204 memcpy(real_buffer + 8, buffer, len);
2205 len += 8;
2206 real_buffer[0] = 0;
2207 real_buffer[1] = 0;
2208 real_buffer[2] = data->medium_type;
2209 real_buffer[3] = data->device_specific;
2210 real_buffer[4] = data->longlba ? 0x01 : 0;
2211 real_buffer[5] = 0;
2212 put_unaligned_be16(data->block_descriptor_length,
2213 &real_buffer[6]);
2214
2215 cmd[0] = MODE_SELECT_10;
2216 put_unaligned_be16(len, &cmd[7]);
2217 } else {
2218 if (data->longlba)
2219 return -EINVAL;
2220
2221 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2222 if (!real_buffer)
2223 return -ENOMEM;
2224 memcpy(real_buffer + 4, buffer, len);
2225 len += 4;
2226 real_buffer[0] = 0;
2227 real_buffer[1] = data->medium_type;
2228 real_buffer[2] = data->device_specific;
2229 real_buffer[3] = data->block_descriptor_length;
2230
2231 cmd[0] = MODE_SELECT;
2232 cmd[4] = len;
2233 }
2234
2235 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2236 timeout, retries, &exec_args);
2237 kfree(real_buffer);
2238 return ret;
2239}
2240EXPORT_SYMBOL_GPL(scsi_mode_select);
2241
2242/**
2243 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2244 * @sdev: SCSI device to be queried
2245 * @dbd: set to prevent mode sense from returning block descriptors
2246 * @modepage: mode page being requested
2247 * @subpage: sub-page of the mode page being requested
2248 * @buffer: request buffer (may not be smaller than eight bytes)
2249 * @len: length of request buffer.
2250 * @timeout: command timeout
2251 * @retries: number of retries before failing
2252 * @data: returns a structure abstracting the mode header data
2253 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2254 * must be SCSI_SENSE_BUFFERSIZE big.
2255 *
2256 * Returns zero if successful, or a negative error number on failure
2257 */
2258int
2259scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2260 unsigned char *buffer, int len, int timeout, int retries,
2261 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2262{
2263 unsigned char cmd[12];
2264 int use_10_for_ms;
2265 int header_length;
2266 int result;
2267 struct scsi_sense_hdr my_sshdr;
2268 struct scsi_failure failure_defs[] = {
2269 {
2270 .sense = UNIT_ATTENTION,
2271 .asc = SCMD_FAILURE_ASC_ANY,
2272 .ascq = SCMD_FAILURE_ASCQ_ANY,
2273 .allowed = retries,
2274 .result = SAM_STAT_CHECK_CONDITION,
2275 },
2276 {}
2277 };
2278 struct scsi_failures failures = {
2279 .failure_definitions = failure_defs,
2280 };
2281 const struct scsi_exec_args exec_args = {
2282 /* caller might not be interested in sense, but we need it */
2283 .sshdr = sshdr ? : &my_sshdr,
2284 .failures = &failures,
2285 };
2286
2287 memset(data, 0, sizeof(*data));
2288 memset(&cmd[0], 0, 12);
2289
2290 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2291 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2292 cmd[2] = modepage;
2293 cmd[3] = subpage;
2294
2295 sshdr = exec_args.sshdr;
2296
2297 retry:
2298 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2299
2300 if (use_10_for_ms) {
2301 if (len < 8 || len > 65535)
2302 return -EINVAL;
2303
2304 cmd[0] = MODE_SENSE_10;
2305 put_unaligned_be16(len, &cmd[7]);
2306 header_length = 8;
2307 } else {
2308 if (len < 4)
2309 return -EINVAL;
2310
2311 cmd[0] = MODE_SENSE;
2312 cmd[4] = len;
2313 header_length = 4;
2314 }
2315
2316 memset(buffer, 0, len);
2317
2318 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2319 timeout, retries, &exec_args);
2320 if (result < 0)
2321 return result;
2322
2323 /* This code looks awful: what it's doing is making sure an
2324 * ILLEGAL REQUEST sense return identifies the actual command
2325 * byte as the problem. MODE_SENSE commands can return
2326 * ILLEGAL REQUEST if the code page isn't supported */
2327
2328 if (!scsi_status_is_good(result)) {
2329 if (scsi_sense_valid(sshdr)) {
2330 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2331 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2332 /*
2333 * Invalid command operation code: retry using
2334 * MODE SENSE(6) if this was a MODE SENSE(10)
2335 * request, except if the request mode page is
2336 * too large for MODE SENSE single byte
2337 * allocation length field.
2338 */
2339 if (use_10_for_ms) {
2340 if (len > 255)
2341 return -EIO;
2342 sdev->use_10_for_ms = 0;
2343 goto retry;
2344 }
2345 }
2346 }
2347 return -EIO;
2348 }
2349 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2350 (modepage == 6 || modepage == 8))) {
2351 /* Initio breakage? */
2352 header_length = 0;
2353 data->length = 13;
2354 data->medium_type = 0;
2355 data->device_specific = 0;
2356 data->longlba = 0;
2357 data->block_descriptor_length = 0;
2358 } else if (use_10_for_ms) {
2359 data->length = get_unaligned_be16(&buffer[0]) + 2;
2360 data->medium_type = buffer[2];
2361 data->device_specific = buffer[3];
2362 data->longlba = buffer[4] & 0x01;
2363 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2364 } else {
2365 data->length = buffer[0] + 1;
2366 data->medium_type = buffer[1];
2367 data->device_specific = buffer[2];
2368 data->block_descriptor_length = buffer[3];
2369 }
2370 data->header_length = header_length;
2371
2372 return 0;
2373}
2374EXPORT_SYMBOL(scsi_mode_sense);
2375
2376/**
2377 * scsi_test_unit_ready - test if unit is ready
2378 * @sdev: scsi device to change the state of.
2379 * @timeout: command timeout
2380 * @retries: number of retries before failing
2381 * @sshdr: outpout pointer for decoded sense information.
2382 *
2383 * Returns zero if unsuccessful or an error if TUR failed. For
2384 * removable media, UNIT_ATTENTION sets ->changed flag.
2385 **/
2386int
2387scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2388 struct scsi_sense_hdr *sshdr)
2389{
2390 char cmd[] = {
2391 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2392 };
2393 const struct scsi_exec_args exec_args = {
2394 .sshdr = sshdr,
2395 };
2396 int result;
2397
2398 /* try to eat the UNIT_ATTENTION if there are enough retries */
2399 do {
2400 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2401 timeout, 1, &exec_args);
2402 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
2403 sshdr->sense_key == UNIT_ATTENTION)
2404 sdev->changed = 1;
2405 } while (result > 0 && scsi_sense_valid(sshdr) &&
2406 sshdr->sense_key == UNIT_ATTENTION && --retries);
2407
2408 return result;
2409}
2410EXPORT_SYMBOL(scsi_test_unit_ready);
2411
2412/**
2413 * scsi_device_set_state - Take the given device through the device state model.
2414 * @sdev: scsi device to change the state of.
2415 * @state: state to change to.
2416 *
2417 * Returns zero if successful or an error if the requested
2418 * transition is illegal.
2419 */
2420int
2421scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2422{
2423 enum scsi_device_state oldstate = sdev->sdev_state;
2424
2425 if (state == oldstate)
2426 return 0;
2427
2428 switch (state) {
2429 case SDEV_CREATED:
2430 switch (oldstate) {
2431 case SDEV_CREATED_BLOCK:
2432 break;
2433 default:
2434 goto illegal;
2435 }
2436 break;
2437
2438 case SDEV_RUNNING:
2439 switch (oldstate) {
2440 case SDEV_CREATED:
2441 case SDEV_OFFLINE:
2442 case SDEV_TRANSPORT_OFFLINE:
2443 case SDEV_QUIESCE:
2444 case SDEV_BLOCK:
2445 break;
2446 default:
2447 goto illegal;
2448 }
2449 break;
2450
2451 case SDEV_QUIESCE:
2452 switch (oldstate) {
2453 case SDEV_RUNNING:
2454 case SDEV_OFFLINE:
2455 case SDEV_TRANSPORT_OFFLINE:
2456 break;
2457 default:
2458 goto illegal;
2459 }
2460 break;
2461
2462 case SDEV_OFFLINE:
2463 case SDEV_TRANSPORT_OFFLINE:
2464 switch (oldstate) {
2465 case SDEV_CREATED:
2466 case SDEV_RUNNING:
2467 case SDEV_QUIESCE:
2468 case SDEV_BLOCK:
2469 break;
2470 default:
2471 goto illegal;
2472 }
2473 break;
2474
2475 case SDEV_BLOCK:
2476 switch (oldstate) {
2477 case SDEV_RUNNING:
2478 case SDEV_CREATED_BLOCK:
2479 case SDEV_QUIESCE:
2480 case SDEV_OFFLINE:
2481 break;
2482 default:
2483 goto illegal;
2484 }
2485 break;
2486
2487 case SDEV_CREATED_BLOCK:
2488 switch (oldstate) {
2489 case SDEV_CREATED:
2490 break;
2491 default:
2492 goto illegal;
2493 }
2494 break;
2495
2496 case SDEV_CANCEL:
2497 switch (oldstate) {
2498 case SDEV_CREATED:
2499 case SDEV_RUNNING:
2500 case SDEV_QUIESCE:
2501 case SDEV_OFFLINE:
2502 case SDEV_TRANSPORT_OFFLINE:
2503 break;
2504 default:
2505 goto illegal;
2506 }
2507 break;
2508
2509 case SDEV_DEL:
2510 switch (oldstate) {
2511 case SDEV_CREATED:
2512 case SDEV_RUNNING:
2513 case SDEV_OFFLINE:
2514 case SDEV_TRANSPORT_OFFLINE:
2515 case SDEV_CANCEL:
2516 case SDEV_BLOCK:
2517 case SDEV_CREATED_BLOCK:
2518 break;
2519 default:
2520 goto illegal;
2521 }
2522 break;
2523
2524 }
2525 sdev->offline_already = false;
2526 sdev->sdev_state = state;
2527 return 0;
2528
2529 illegal:
2530 SCSI_LOG_ERROR_RECOVERY(1,
2531 sdev_printk(KERN_ERR, sdev,
2532 "Illegal state transition %s->%s",
2533 scsi_device_state_name(oldstate),
2534 scsi_device_state_name(state))
2535 );
2536 return -EINVAL;
2537}
2538EXPORT_SYMBOL(scsi_device_set_state);
2539
2540/**
2541 * scsi_evt_emit - emit a single SCSI device uevent
2542 * @sdev: associated SCSI device
2543 * @evt: event to emit
2544 *
2545 * Send a single uevent (scsi_event) to the associated scsi_device.
2546 */
2547static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2548{
2549 int idx = 0;
2550 char *envp[3];
2551
2552 switch (evt->evt_type) {
2553 case SDEV_EVT_MEDIA_CHANGE:
2554 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2555 break;
2556 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2557 scsi_rescan_device(sdev);
2558 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2559 break;
2560 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2561 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2562 break;
2563 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2564 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2565 break;
2566 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2567 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2568 break;
2569 case SDEV_EVT_LUN_CHANGE_REPORTED:
2570 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2571 break;
2572 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2573 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2574 break;
2575 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2576 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2577 break;
2578 default:
2579 /* do nothing */
2580 break;
2581 }
2582
2583 envp[idx++] = NULL;
2584
2585 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2586}
2587
2588/**
2589 * scsi_evt_thread - send a uevent for each scsi event
2590 * @work: work struct for scsi_device
2591 *
2592 * Dispatch queued events to their associated scsi_device kobjects
2593 * as uevents.
2594 */
2595void scsi_evt_thread(struct work_struct *work)
2596{
2597 struct scsi_device *sdev;
2598 enum scsi_device_event evt_type;
2599 LIST_HEAD(event_list);
2600
2601 sdev = container_of(work, struct scsi_device, event_work);
2602
2603 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2604 if (test_and_clear_bit(evt_type, sdev->pending_events))
2605 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2606
2607 while (1) {
2608 struct scsi_event *evt;
2609 struct list_head *this, *tmp;
2610 unsigned long flags;
2611
2612 spin_lock_irqsave(&sdev->list_lock, flags);
2613 list_splice_init(&sdev->event_list, &event_list);
2614 spin_unlock_irqrestore(&sdev->list_lock, flags);
2615
2616 if (list_empty(&event_list))
2617 break;
2618
2619 list_for_each_safe(this, tmp, &event_list) {
2620 evt = list_entry(this, struct scsi_event, node);
2621 list_del(&evt->node);
2622 scsi_evt_emit(sdev, evt);
2623 kfree(evt);
2624 }
2625 }
2626}
2627
2628/**
2629 * sdev_evt_send - send asserted event to uevent thread
2630 * @sdev: scsi_device event occurred on
2631 * @evt: event to send
2632 *
2633 * Assert scsi device event asynchronously.
2634 */
2635void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2636{
2637 unsigned long flags;
2638
2639#if 0
2640 /* FIXME: currently this check eliminates all media change events
2641 * for polled devices. Need to update to discriminate between AN
2642 * and polled events */
2643 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2644 kfree(evt);
2645 return;
2646 }
2647#endif
2648
2649 spin_lock_irqsave(&sdev->list_lock, flags);
2650 list_add_tail(&evt->node, &sdev->event_list);
2651 schedule_work(&sdev->event_work);
2652 spin_unlock_irqrestore(&sdev->list_lock, flags);
2653}
2654EXPORT_SYMBOL_GPL(sdev_evt_send);
2655
2656/**
2657 * sdev_evt_alloc - allocate a new scsi event
2658 * @evt_type: type of event to allocate
2659 * @gfpflags: GFP flags for allocation
2660 *
2661 * Allocates and returns a new scsi_event.
2662 */
2663struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2664 gfp_t gfpflags)
2665{
2666 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2667 if (!evt)
2668 return NULL;
2669
2670 evt->evt_type = evt_type;
2671 INIT_LIST_HEAD(&evt->node);
2672
2673 /* evt_type-specific initialization, if any */
2674 switch (evt_type) {
2675 case SDEV_EVT_MEDIA_CHANGE:
2676 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2677 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2678 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2679 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2680 case SDEV_EVT_LUN_CHANGE_REPORTED:
2681 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2682 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2683 default:
2684 /* do nothing */
2685 break;
2686 }
2687
2688 return evt;
2689}
2690EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2691
2692/**
2693 * sdev_evt_send_simple - send asserted event to uevent thread
2694 * @sdev: scsi_device event occurred on
2695 * @evt_type: type of event to send
2696 * @gfpflags: GFP flags for allocation
2697 *
2698 * Assert scsi device event asynchronously, given an event type.
2699 */
2700void sdev_evt_send_simple(struct scsi_device *sdev,
2701 enum scsi_device_event evt_type, gfp_t gfpflags)
2702{
2703 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2704 if (!evt) {
2705 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2706 evt_type);
2707 return;
2708 }
2709
2710 sdev_evt_send(sdev, evt);
2711}
2712EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2713
2714/**
2715 * scsi_device_quiesce - Block all commands except power management.
2716 * @sdev: scsi device to quiesce.
2717 *
2718 * This works by trying to transition to the SDEV_QUIESCE state
2719 * (which must be a legal transition). When the device is in this
2720 * state, only power management requests will be accepted, all others will
2721 * be deferred.
2722 *
2723 * Must be called with user context, may sleep.
2724 *
2725 * Returns zero if unsuccessful or an error if not.
2726 */
2727int
2728scsi_device_quiesce(struct scsi_device *sdev)
2729{
2730 struct request_queue *q = sdev->request_queue;
2731 int err;
2732
2733 /*
2734 * It is allowed to call scsi_device_quiesce() multiple times from
2735 * the same context but concurrent scsi_device_quiesce() calls are
2736 * not allowed.
2737 */
2738 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2739
2740 if (sdev->quiesced_by == current)
2741 return 0;
2742
2743 blk_set_pm_only(q);
2744
2745 blk_mq_freeze_queue(q);
2746 /*
2747 * Ensure that the effect of blk_set_pm_only() will be visible
2748 * for percpu_ref_tryget() callers that occur after the queue
2749 * unfreeze even if the queue was already frozen before this function
2750 * was called. See also https://lwn.net/Articles/573497/.
2751 */
2752 synchronize_rcu();
2753 blk_mq_unfreeze_queue(q);
2754
2755 mutex_lock(&sdev->state_mutex);
2756 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2757 if (err == 0)
2758 sdev->quiesced_by = current;
2759 else
2760 blk_clear_pm_only(q);
2761 mutex_unlock(&sdev->state_mutex);
2762
2763 return err;
2764}
2765EXPORT_SYMBOL(scsi_device_quiesce);
2766
2767/**
2768 * scsi_device_resume - Restart user issued commands to a quiesced device.
2769 * @sdev: scsi device to resume.
2770 *
2771 * Moves the device from quiesced back to running and restarts the
2772 * queues.
2773 *
2774 * Must be called with user context, may sleep.
2775 */
2776void scsi_device_resume(struct scsi_device *sdev)
2777{
2778 /* check if the device state was mutated prior to resume, and if
2779 * so assume the state is being managed elsewhere (for example
2780 * device deleted during suspend)
2781 */
2782 mutex_lock(&sdev->state_mutex);
2783 if (sdev->sdev_state == SDEV_QUIESCE)
2784 scsi_device_set_state(sdev, SDEV_RUNNING);
2785 if (sdev->quiesced_by) {
2786 sdev->quiesced_by = NULL;
2787 blk_clear_pm_only(sdev->request_queue);
2788 }
2789 mutex_unlock(&sdev->state_mutex);
2790}
2791EXPORT_SYMBOL(scsi_device_resume);
2792
2793static void
2794device_quiesce_fn(struct scsi_device *sdev, void *data)
2795{
2796 scsi_device_quiesce(sdev);
2797}
2798
2799void
2800scsi_target_quiesce(struct scsi_target *starget)
2801{
2802 starget_for_each_device(starget, NULL, device_quiesce_fn);
2803}
2804EXPORT_SYMBOL(scsi_target_quiesce);
2805
2806static void
2807device_resume_fn(struct scsi_device *sdev, void *data)
2808{
2809 scsi_device_resume(sdev);
2810}
2811
2812void
2813scsi_target_resume(struct scsi_target *starget)
2814{
2815 starget_for_each_device(starget, NULL, device_resume_fn);
2816}
2817EXPORT_SYMBOL(scsi_target_resume);
2818
2819static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2820{
2821 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2822 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2823
2824 return 0;
2825}
2826
2827void scsi_start_queue(struct scsi_device *sdev)
2828{
2829 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2830 blk_mq_unquiesce_queue(sdev->request_queue);
2831}
2832
2833static void scsi_stop_queue(struct scsi_device *sdev)
2834{
2835 /*
2836 * The atomic variable of ->queue_stopped covers that
2837 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2838 *
2839 * The caller needs to wait until quiesce is done.
2840 */
2841 if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2842 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2843}
2844
2845/**
2846 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2847 * @sdev: device to block
2848 *
2849 * Pause SCSI command processing on the specified device. Does not sleep.
2850 *
2851 * Returns zero if successful or a negative error code upon failure.
2852 *
2853 * Notes:
2854 * This routine transitions the device to the SDEV_BLOCK state (which must be
2855 * a legal transition). When the device is in this state, command processing
2856 * is paused until the device leaves the SDEV_BLOCK state. See also
2857 * scsi_internal_device_unblock_nowait().
2858 */
2859int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2860{
2861 int ret = __scsi_internal_device_block_nowait(sdev);
2862
2863 /*
2864 * The device has transitioned to SDEV_BLOCK. Stop the
2865 * block layer from calling the midlayer with this device's
2866 * request queue.
2867 */
2868 if (!ret)
2869 scsi_stop_queue(sdev);
2870 return ret;
2871}
2872EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2873
2874/**
2875 * scsi_device_block - try to transition to the SDEV_BLOCK state
2876 * @sdev: device to block
2877 * @data: dummy argument, ignored
2878 *
2879 * Pause SCSI command processing on the specified device. Callers must wait
2880 * until all ongoing scsi_queue_rq() calls have finished after this function
2881 * returns.
2882 *
2883 * Note:
2884 * This routine transitions the device to the SDEV_BLOCK state (which must be
2885 * a legal transition). When the device is in this state, command processing
2886 * is paused until the device leaves the SDEV_BLOCK state. See also
2887 * scsi_internal_device_unblock().
2888 */
2889static void scsi_device_block(struct scsi_device *sdev, void *data)
2890{
2891 int err;
2892 enum scsi_device_state state;
2893
2894 mutex_lock(&sdev->state_mutex);
2895 err = __scsi_internal_device_block_nowait(sdev);
2896 state = sdev->sdev_state;
2897 if (err == 0)
2898 /*
2899 * scsi_stop_queue() must be called with the state_mutex
2900 * held. Otherwise a simultaneous scsi_start_queue() call
2901 * might unquiesce the queue before we quiesce it.
2902 */
2903 scsi_stop_queue(sdev);
2904
2905 mutex_unlock(&sdev->state_mutex);
2906
2907 WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2908 __func__, dev_name(&sdev->sdev_gendev), state);
2909}
2910
2911/**
2912 * scsi_internal_device_unblock_nowait - resume a device after a block request
2913 * @sdev: device to resume
2914 * @new_state: state to set the device to after unblocking
2915 *
2916 * Restart the device queue for a previously suspended SCSI device. Does not
2917 * sleep.
2918 *
2919 * Returns zero if successful or a negative error code upon failure.
2920 *
2921 * Notes:
2922 * This routine transitions the device to the SDEV_RUNNING state or to one of
2923 * the offline states (which must be a legal transition) allowing the midlayer
2924 * to goose the queue for this device.
2925 */
2926int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2927 enum scsi_device_state new_state)
2928{
2929 switch (new_state) {
2930 case SDEV_RUNNING:
2931 case SDEV_TRANSPORT_OFFLINE:
2932 break;
2933 default:
2934 return -EINVAL;
2935 }
2936
2937 /*
2938 * Try to transition the scsi device to SDEV_RUNNING or one of the
2939 * offlined states and goose the device queue if successful.
2940 */
2941 switch (sdev->sdev_state) {
2942 case SDEV_BLOCK:
2943 case SDEV_TRANSPORT_OFFLINE:
2944 sdev->sdev_state = new_state;
2945 break;
2946 case SDEV_CREATED_BLOCK:
2947 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2948 new_state == SDEV_OFFLINE)
2949 sdev->sdev_state = new_state;
2950 else
2951 sdev->sdev_state = SDEV_CREATED;
2952 break;
2953 case SDEV_CANCEL:
2954 case SDEV_OFFLINE:
2955 break;
2956 default:
2957 return -EINVAL;
2958 }
2959 scsi_start_queue(sdev);
2960
2961 return 0;
2962}
2963EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2964
2965/**
2966 * scsi_internal_device_unblock - resume a device after a block request
2967 * @sdev: device to resume
2968 * @new_state: state to set the device to after unblocking
2969 *
2970 * Restart the device queue for a previously suspended SCSI device. May sleep.
2971 *
2972 * Returns zero if successful or a negative error code upon failure.
2973 *
2974 * Notes:
2975 * This routine transitions the device to the SDEV_RUNNING state or to one of
2976 * the offline states (which must be a legal transition) allowing the midlayer
2977 * to goose the queue for this device.
2978 */
2979static int scsi_internal_device_unblock(struct scsi_device *sdev,
2980 enum scsi_device_state new_state)
2981{
2982 int ret;
2983
2984 mutex_lock(&sdev->state_mutex);
2985 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2986 mutex_unlock(&sdev->state_mutex);
2987
2988 return ret;
2989}
2990
2991static int
2992target_block(struct device *dev, void *data)
2993{
2994 if (scsi_is_target_device(dev))
2995 starget_for_each_device(to_scsi_target(dev), NULL,
2996 scsi_device_block);
2997 return 0;
2998}
2999
3000/**
3001 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
3002 * @dev: a parent device of one or more scsi_target devices
3003 * @shost: the Scsi_Host to which this device belongs
3004 *
3005 * Iterate over all children of @dev, which should be scsi_target devices,
3006 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
3007 * ongoing scsi_queue_rq() calls to finish. May sleep.
3008 *
3009 * Note:
3010 * @dev must not itself be a scsi_target device.
3011 */
3012void
3013scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
3014{
3015 WARN_ON_ONCE(scsi_is_target_device(dev));
3016 device_for_each_child(dev, NULL, target_block);
3017 blk_mq_wait_quiesce_done(&shost->tag_set);
3018}
3019EXPORT_SYMBOL_GPL(scsi_block_targets);
3020
3021static void
3022device_unblock(struct scsi_device *sdev, void *data)
3023{
3024 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3025}
3026
3027static int
3028target_unblock(struct device *dev, void *data)
3029{
3030 if (scsi_is_target_device(dev))
3031 starget_for_each_device(to_scsi_target(dev), data,
3032 device_unblock);
3033 return 0;
3034}
3035
3036void
3037scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3038{
3039 if (scsi_is_target_device(dev))
3040 starget_for_each_device(to_scsi_target(dev), &new_state,
3041 device_unblock);
3042 else
3043 device_for_each_child(dev, &new_state, target_unblock);
3044}
3045EXPORT_SYMBOL_GPL(scsi_target_unblock);
3046
3047/**
3048 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
3049 * @shost: device to block
3050 *
3051 * Pause SCSI command processing for all logical units associated with the SCSI
3052 * host and wait until pending scsi_queue_rq() calls have finished.
3053 *
3054 * Returns zero if successful or a negative error code upon failure.
3055 */
3056int
3057scsi_host_block(struct Scsi_Host *shost)
3058{
3059 struct scsi_device *sdev;
3060 int ret;
3061
3062 /*
3063 * Call scsi_internal_device_block_nowait so we can avoid
3064 * calling synchronize_rcu() for each LUN.
3065 */
3066 shost_for_each_device(sdev, shost) {
3067 mutex_lock(&sdev->state_mutex);
3068 ret = scsi_internal_device_block_nowait(sdev);
3069 mutex_unlock(&sdev->state_mutex);
3070 if (ret) {
3071 scsi_device_put(sdev);
3072 return ret;
3073 }
3074 }
3075
3076 /* Wait for ongoing scsi_queue_rq() calls to finish. */
3077 blk_mq_wait_quiesce_done(&shost->tag_set);
3078
3079 return 0;
3080}
3081EXPORT_SYMBOL_GPL(scsi_host_block);
3082
3083int
3084scsi_host_unblock(struct Scsi_Host *shost, int new_state)
3085{
3086 struct scsi_device *sdev;
3087 int ret = 0;
3088
3089 shost_for_each_device(sdev, shost) {
3090 ret = scsi_internal_device_unblock(sdev, new_state);
3091 if (ret) {
3092 scsi_device_put(sdev);
3093 break;
3094 }
3095 }
3096 return ret;
3097}
3098EXPORT_SYMBOL_GPL(scsi_host_unblock);
3099
3100/**
3101 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3102 * @sgl: scatter-gather list
3103 * @sg_count: number of segments in sg
3104 * @offset: offset in bytes into sg, on return offset into the mapped area
3105 * @len: bytes to map, on return number of bytes mapped
3106 *
3107 * Returns virtual address of the start of the mapped page
3108 */
3109void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3110 size_t *offset, size_t *len)
3111{
3112 int i;
3113 size_t sg_len = 0, len_complete = 0;
3114 struct scatterlist *sg;
3115 struct page *page;
3116
3117 WARN_ON(!irqs_disabled());
3118
3119 for_each_sg(sgl, sg, sg_count, i) {
3120 len_complete = sg_len; /* Complete sg-entries */
3121 sg_len += sg->length;
3122 if (sg_len > *offset)
3123 break;
3124 }
3125
3126 if (unlikely(i == sg_count)) {
3127 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3128 "elements %d\n",
3129 __func__, sg_len, *offset, sg_count);
3130 WARN_ON(1);
3131 return NULL;
3132 }
3133
3134 /* Offset starting from the beginning of first page in this sg-entry */
3135 *offset = *offset - len_complete + sg->offset;
3136
3137 /* Assumption: contiguous pages can be accessed as "page + i" */
3138 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3139 *offset &= ~PAGE_MASK;
3140
3141 /* Bytes in this sg-entry from *offset to the end of the page */
3142 sg_len = PAGE_SIZE - *offset;
3143 if (*len > sg_len)
3144 *len = sg_len;
3145
3146 return kmap_atomic(page);
3147}
3148EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3149
3150/**
3151 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3152 * @virt: virtual address to be unmapped
3153 */
3154void scsi_kunmap_atomic_sg(void *virt)
3155{
3156 kunmap_atomic(virt);
3157}
3158EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3159
3160void sdev_disable_disk_events(struct scsi_device *sdev)
3161{
3162 atomic_inc(&sdev->disk_events_disable_depth);
3163}
3164EXPORT_SYMBOL(sdev_disable_disk_events);
3165
3166void sdev_enable_disk_events(struct scsi_device *sdev)
3167{
3168 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3169 return;
3170 atomic_dec(&sdev->disk_events_disable_depth);
3171}
3172EXPORT_SYMBOL(sdev_enable_disk_events);
3173
3174static unsigned char designator_prio(const unsigned char *d)
3175{
3176 if (d[1] & 0x30)
3177 /* not associated with LUN */
3178 return 0;
3179
3180 if (d[3] == 0)
3181 /* invalid length */
3182 return 0;
3183
3184 /*
3185 * Order of preference for lun descriptor:
3186 * - SCSI name string
3187 * - NAA IEEE Registered Extended
3188 * - EUI-64 based 16-byte
3189 * - EUI-64 based 12-byte
3190 * - NAA IEEE Registered
3191 * - NAA IEEE Extended
3192 * - EUI-64 based 8-byte
3193 * - SCSI name string (truncated)
3194 * - T10 Vendor ID
3195 * as longer descriptors reduce the likelyhood
3196 * of identification clashes.
3197 */
3198
3199 switch (d[1] & 0xf) {
3200 case 8:
3201 /* SCSI name string, variable-length UTF-8 */
3202 return 9;
3203 case 3:
3204 switch (d[4] >> 4) {
3205 case 6:
3206 /* NAA registered extended */
3207 return 8;
3208 case 5:
3209 /* NAA registered */
3210 return 5;
3211 case 4:
3212 /* NAA extended */
3213 return 4;
3214 case 3:
3215 /* NAA locally assigned */
3216 return 1;
3217 default:
3218 break;
3219 }
3220 break;
3221 case 2:
3222 switch (d[3]) {
3223 case 16:
3224 /* EUI64-based, 16 byte */
3225 return 7;
3226 case 12:
3227 /* EUI64-based, 12 byte */
3228 return 6;
3229 case 8:
3230 /* EUI64-based, 8 byte */
3231 return 3;
3232 default:
3233 break;
3234 }
3235 break;
3236 case 1:
3237 /* T10 vendor ID */
3238 return 1;
3239 default:
3240 break;
3241 }
3242
3243 return 0;
3244}
3245
3246/**
3247 * scsi_vpd_lun_id - return a unique device identification
3248 * @sdev: SCSI device
3249 * @id: buffer for the identification
3250 * @id_len: length of the buffer
3251 *
3252 * Copies a unique device identification into @id based
3253 * on the information in the VPD page 0x83 of the device.
3254 * The string will be formatted as a SCSI name string.
3255 *
3256 * Returns the length of the identification or error on failure.
3257 * If the identifier is longer than the supplied buffer the actual
3258 * identifier length is returned and the buffer is not zero-padded.
3259 */
3260int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3261{
3262 u8 cur_id_prio = 0;
3263 u8 cur_id_size = 0;
3264 const unsigned char *d, *cur_id_str;
3265 const struct scsi_vpd *vpd_pg83;
3266 int id_size = -EINVAL;
3267
3268 rcu_read_lock();
3269 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3270 if (!vpd_pg83) {
3271 rcu_read_unlock();
3272 return -ENXIO;
3273 }
3274
3275 /* The id string must be at least 20 bytes + terminating NULL byte */
3276 if (id_len < 21) {
3277 rcu_read_unlock();
3278 return -EINVAL;
3279 }
3280
3281 memset(id, 0, id_len);
3282 for (d = vpd_pg83->data + 4;
3283 d < vpd_pg83->data + vpd_pg83->len;
3284 d += d[3] + 4) {
3285 u8 prio = designator_prio(d);
3286
3287 if (prio == 0 || cur_id_prio > prio)
3288 continue;
3289
3290 switch (d[1] & 0xf) {
3291 case 0x1:
3292 /* T10 Vendor ID */
3293 if (cur_id_size > d[3])
3294 break;
3295 cur_id_prio = prio;
3296 cur_id_size = d[3];
3297 if (cur_id_size + 4 > id_len)
3298 cur_id_size = id_len - 4;
3299 cur_id_str = d + 4;
3300 id_size = snprintf(id, id_len, "t10.%*pE",
3301 cur_id_size, cur_id_str);
3302 break;
3303 case 0x2:
3304 /* EUI-64 */
3305 cur_id_prio = prio;
3306 cur_id_size = d[3];
3307 cur_id_str = d + 4;
3308 switch (cur_id_size) {
3309 case 8:
3310 id_size = snprintf(id, id_len,
3311 "eui.%8phN",
3312 cur_id_str);
3313 break;
3314 case 12:
3315 id_size = snprintf(id, id_len,
3316 "eui.%12phN",
3317 cur_id_str);
3318 break;
3319 case 16:
3320 id_size = snprintf(id, id_len,
3321 "eui.%16phN",
3322 cur_id_str);
3323 break;
3324 default:
3325 break;
3326 }
3327 break;
3328 case 0x3:
3329 /* NAA */
3330 cur_id_prio = prio;
3331 cur_id_size = d[3];
3332 cur_id_str = d + 4;
3333 switch (cur_id_size) {
3334 case 8:
3335 id_size = snprintf(id, id_len,
3336 "naa.%8phN",
3337 cur_id_str);
3338 break;
3339 case 16:
3340 id_size = snprintf(id, id_len,
3341 "naa.%16phN",
3342 cur_id_str);
3343 break;
3344 default:
3345 break;
3346 }
3347 break;
3348 case 0x8:
3349 /* SCSI name string */
3350 if (cur_id_size > d[3])
3351 break;
3352 /* Prefer others for truncated descriptor */
3353 if (d[3] > id_len) {
3354 prio = 2;
3355 if (cur_id_prio > prio)
3356 break;
3357 }
3358 cur_id_prio = prio;
3359 cur_id_size = id_size = d[3];
3360 cur_id_str = d + 4;
3361 if (cur_id_size >= id_len)
3362 cur_id_size = id_len - 1;
3363 memcpy(id, cur_id_str, cur_id_size);
3364 break;
3365 default:
3366 break;
3367 }
3368 }
3369 rcu_read_unlock();
3370
3371 return id_size;
3372}
3373EXPORT_SYMBOL(scsi_vpd_lun_id);
3374
3375/*
3376 * scsi_vpd_tpg_id - return a target port group identifier
3377 * @sdev: SCSI device
3378 *
3379 * Returns the Target Port Group identifier from the information
3380 * froom VPD page 0x83 of the device.
3381 *
3382 * Returns the identifier or error on failure.
3383 */
3384int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3385{
3386 const unsigned char *d;
3387 const struct scsi_vpd *vpd_pg83;
3388 int group_id = -EAGAIN, rel_port = -1;
3389
3390 rcu_read_lock();
3391 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3392 if (!vpd_pg83) {
3393 rcu_read_unlock();
3394 return -ENXIO;
3395 }
3396
3397 d = vpd_pg83->data + 4;
3398 while (d < vpd_pg83->data + vpd_pg83->len) {
3399 switch (d[1] & 0xf) {
3400 case 0x4:
3401 /* Relative target port */
3402 rel_port = get_unaligned_be16(&d[6]);
3403 break;
3404 case 0x5:
3405 /* Target port group */
3406 group_id = get_unaligned_be16(&d[6]);
3407 break;
3408 default:
3409 break;
3410 }
3411 d += d[3] + 4;
3412 }
3413 rcu_read_unlock();
3414
3415 if (group_id >= 0 && rel_id && rel_port != -1)
3416 *rel_id = rel_port;
3417
3418 return group_id;
3419}
3420EXPORT_SYMBOL(scsi_vpd_tpg_id);
3421
3422/**
3423 * scsi_build_sense - build sense data for a command
3424 * @scmd: scsi command for which the sense should be formatted
3425 * @desc: Sense format (non-zero == descriptor format,
3426 * 0 == fixed format)
3427 * @key: Sense key
3428 * @asc: Additional sense code
3429 * @ascq: Additional sense code qualifier
3430 *
3431 **/
3432void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3433{
3434 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3435 scmd->result = SAM_STAT_CHECK_CONDITION;
3436}
3437EXPORT_SYMBOL_GPL(scsi_build_sense);
3438
3439#ifdef CONFIG_SCSI_LIB_KUNIT_TEST
3440#include "scsi_lib_test.c"
3441#endif