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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/ratelimit.h>
25#include <asm/unaligned.h>
26
27#include <scsi/scsi.h>
28#include <scsi/scsi_cmnd.h>
29#include <scsi/scsi_dbg.h>
30#include <scsi/scsi_device.h>
31#include <scsi/scsi_driver.h>
32#include <scsi/scsi_eh.h>
33#include <scsi/scsi_host.h>
34#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
35#include <scsi/scsi_dh.h>
36
37#include <trace/events/scsi.h>
38
39#include "scsi_debugfs.h"
40#include "scsi_priv.h"
41#include "scsi_logging.h"
42
43/*
44 * Size of integrity metadata is usually small, 1 inline sg should
45 * cover normal cases.
46 */
47#ifdef CONFIG_ARCH_NO_SG_CHAIN
48#define SCSI_INLINE_PROT_SG_CNT 0
49#define SCSI_INLINE_SG_CNT 0
50#else
51#define SCSI_INLINE_PROT_SG_CNT 1
52#define SCSI_INLINE_SG_CNT 2
53#endif
54
55static struct kmem_cache *scsi_sdb_cache;
56static struct kmem_cache *scsi_sense_cache;
57static struct kmem_cache *scsi_sense_isadma_cache;
58static DEFINE_MUTEX(scsi_sense_cache_mutex);
59
60static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
61
62static inline struct kmem_cache *
63scsi_select_sense_cache(bool unchecked_isa_dma)
64{
65 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
66}
67
68static void scsi_free_sense_buffer(bool unchecked_isa_dma,
69 unsigned char *sense_buffer)
70{
71 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
72 sense_buffer);
73}
74
75static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
76 gfp_t gfp_mask, int numa_node)
77{
78 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
79 gfp_mask, numa_node);
80}
81
82int scsi_init_sense_cache(struct Scsi_Host *shost)
83{
84 struct kmem_cache *cache;
85 int ret = 0;
86
87 mutex_lock(&scsi_sense_cache_mutex);
88 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
89 if (cache)
90 goto exit;
91
92 if (shost->unchecked_isa_dma) {
93 scsi_sense_isadma_cache =
94 kmem_cache_create("scsi_sense_cache(DMA)",
95 SCSI_SENSE_BUFFERSIZE, 0,
96 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
97 if (!scsi_sense_isadma_cache)
98 ret = -ENOMEM;
99 } else {
100 scsi_sense_cache =
101 kmem_cache_create_usercopy("scsi_sense_cache",
102 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
103 0, SCSI_SENSE_BUFFERSIZE, NULL);
104 if (!scsi_sense_cache)
105 ret = -ENOMEM;
106 }
107 exit:
108 mutex_unlock(&scsi_sense_cache_mutex);
109 return ret;
110}
111
112/*
113 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
114 * not change behaviour from the previous unplug mechanism, experimentation
115 * may prove this needs changing.
116 */
117#define SCSI_QUEUE_DELAY 3
118
119static void
120scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
121{
122 struct Scsi_Host *host = cmd->device->host;
123 struct scsi_device *device = cmd->device;
124 struct scsi_target *starget = scsi_target(device);
125
126 /*
127 * Set the appropriate busy bit for the device/host.
128 *
129 * If the host/device isn't busy, assume that something actually
130 * completed, and that we should be able to queue a command now.
131 *
132 * Note that the prior mid-layer assumption that any host could
133 * always queue at least one command is now broken. The mid-layer
134 * will implement a user specifiable stall (see
135 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
136 * if a command is requeued with no other commands outstanding
137 * either for the device or for the host.
138 */
139 switch (reason) {
140 case SCSI_MLQUEUE_HOST_BUSY:
141 atomic_set(&host->host_blocked, host->max_host_blocked);
142 break;
143 case SCSI_MLQUEUE_DEVICE_BUSY:
144 case SCSI_MLQUEUE_EH_RETRY:
145 atomic_set(&device->device_blocked,
146 device->max_device_blocked);
147 break;
148 case SCSI_MLQUEUE_TARGET_BUSY:
149 atomic_set(&starget->target_blocked,
150 starget->max_target_blocked);
151 break;
152 }
153}
154
155static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
156{
157 if (cmd->request->rq_flags & RQF_DONTPREP) {
158 cmd->request->rq_flags &= ~RQF_DONTPREP;
159 scsi_mq_uninit_cmd(cmd);
160 } else {
161 WARN_ON_ONCE(true);
162 }
163 blk_mq_requeue_request(cmd->request, true);
164}
165
166/**
167 * __scsi_queue_insert - private queue insertion
168 * @cmd: The SCSI command being requeued
169 * @reason: The reason for the requeue
170 * @unbusy: Whether the queue should be unbusied
171 *
172 * This is a private queue insertion. The public interface
173 * scsi_queue_insert() always assumes the queue should be unbusied
174 * because it's always called before the completion. This function is
175 * for a requeue after completion, which should only occur in this
176 * file.
177 */
178static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
179{
180 struct scsi_device *device = cmd->device;
181
182 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
183 "Inserting command %p into mlqueue\n", cmd));
184
185 scsi_set_blocked(cmd, reason);
186
187 /*
188 * Decrement the counters, since these commands are no longer
189 * active on the host/device.
190 */
191 if (unbusy)
192 scsi_device_unbusy(device);
193
194 /*
195 * Requeue this command. It will go before all other commands
196 * that are already in the queue. Schedule requeue work under
197 * lock such that the kblockd_schedule_work() call happens
198 * before blk_cleanup_queue() finishes.
199 */
200 cmd->result = 0;
201
202 blk_mq_requeue_request(cmd->request, true);
203}
204
205/*
206 * Function: scsi_queue_insert()
207 *
208 * Purpose: Insert a command in the midlevel queue.
209 *
210 * Arguments: cmd - command that we are adding to queue.
211 * reason - why we are inserting command to queue.
212 *
213 * Lock status: Assumed that lock is not held upon entry.
214 *
215 * Returns: Nothing.
216 *
217 * Notes: We do this for one of two cases. Either the host is busy
218 * and it cannot accept any more commands for the time being,
219 * or the device returned QUEUE_FULL and can accept no more
220 * commands.
221 * Notes: This could be called either from an interrupt context or a
222 * normal process context.
223 */
224void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
225{
226 __scsi_queue_insert(cmd, reason, true);
227}
228
229
230/**
231 * __scsi_execute - insert request and wait for the result
232 * @sdev: scsi device
233 * @cmd: scsi command
234 * @data_direction: data direction
235 * @buffer: data buffer
236 * @bufflen: len of buffer
237 * @sense: optional sense buffer
238 * @sshdr: optional decoded sense header
239 * @timeout: request timeout in seconds
240 * @retries: number of times to retry request
241 * @flags: flags for ->cmd_flags
242 * @rq_flags: flags for ->rq_flags
243 * @resid: optional residual length
244 *
245 * Returns the scsi_cmnd result field if a command was executed, or a negative
246 * Linux error code if we didn't get that far.
247 */
248int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
249 int data_direction, void *buffer, unsigned bufflen,
250 unsigned char *sense, struct scsi_sense_hdr *sshdr,
251 int timeout, int retries, u64 flags, req_flags_t rq_flags,
252 int *resid)
253{
254 struct request *req;
255 struct scsi_request *rq;
256 int ret = DRIVER_ERROR << 24;
257
258 req = blk_get_request(sdev->request_queue,
259 data_direction == DMA_TO_DEVICE ?
260 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
261 if (IS_ERR(req))
262 return ret;
263 rq = scsi_req(req);
264
265 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
266 buffer, bufflen, GFP_NOIO))
267 goto out;
268
269 rq->cmd_len = COMMAND_SIZE(cmd[0]);
270 memcpy(rq->cmd, cmd, rq->cmd_len);
271 rq->retries = retries;
272 req->timeout = timeout;
273 req->cmd_flags |= flags;
274 req->rq_flags |= rq_flags | RQF_QUIET;
275
276 /*
277 * head injection *required* here otherwise quiesce won't work
278 */
279 blk_execute_rq(req->q, NULL, req, 1);
280
281 /*
282 * Some devices (USB mass-storage in particular) may transfer
283 * garbage data together with a residue indicating that the data
284 * is invalid. Prevent the garbage from being misinterpreted
285 * and prevent security leaks by zeroing out the excess data.
286 */
287 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
288 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
289
290 if (resid)
291 *resid = rq->resid_len;
292 if (sense && rq->sense_len)
293 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
294 if (sshdr)
295 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
296 ret = rq->result;
297 out:
298 blk_put_request(req);
299
300 return ret;
301}
302EXPORT_SYMBOL(__scsi_execute);
303
304/*
305 * Function: scsi_init_cmd_errh()
306 *
307 * Purpose: Initialize cmd fields related to error handling.
308 *
309 * Arguments: cmd - command that is ready to be queued.
310 *
311 * Notes: This function has the job of initializing a number of
312 * fields related to error handling. Typically this will
313 * be called once for each command, as required.
314 */
315static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
316{
317 scsi_set_resid(cmd, 0);
318 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
319 if (cmd->cmd_len == 0)
320 cmd->cmd_len = scsi_command_size(cmd->cmnd);
321}
322
323/*
324 * Decrement the host_busy counter and wake up the error handler if necessary.
325 * Avoid as follows that the error handler is not woken up if shost->host_busy
326 * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
327 * with an RCU read lock in this function to ensure that this function in its
328 * entirety either finishes before scsi_eh_scmd_add() increases the
329 * host_failed counter or that it notices the shost state change made by
330 * scsi_eh_scmd_add().
331 */
332static void scsi_dec_host_busy(struct Scsi_Host *shost)
333{
334 unsigned long flags;
335
336 rcu_read_lock();
337 atomic_dec(&shost->host_busy);
338 if (unlikely(scsi_host_in_recovery(shost))) {
339 spin_lock_irqsave(shost->host_lock, flags);
340 if (shost->host_failed || shost->host_eh_scheduled)
341 scsi_eh_wakeup(shost);
342 spin_unlock_irqrestore(shost->host_lock, flags);
343 }
344 rcu_read_unlock();
345}
346
347void scsi_device_unbusy(struct scsi_device *sdev)
348{
349 struct Scsi_Host *shost = sdev->host;
350 struct scsi_target *starget = scsi_target(sdev);
351
352 scsi_dec_host_busy(shost);
353
354 if (starget->can_queue > 0)
355 atomic_dec(&starget->target_busy);
356
357 atomic_dec(&sdev->device_busy);
358}
359
360static void scsi_kick_queue(struct request_queue *q)
361{
362 blk_mq_run_hw_queues(q, false);
363}
364
365/*
366 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
367 * and call blk_run_queue for all the scsi_devices on the target -
368 * including current_sdev first.
369 *
370 * Called with *no* scsi locks held.
371 */
372static void scsi_single_lun_run(struct scsi_device *current_sdev)
373{
374 struct Scsi_Host *shost = current_sdev->host;
375 struct scsi_device *sdev, *tmp;
376 struct scsi_target *starget = scsi_target(current_sdev);
377 unsigned long flags;
378
379 spin_lock_irqsave(shost->host_lock, flags);
380 starget->starget_sdev_user = NULL;
381 spin_unlock_irqrestore(shost->host_lock, flags);
382
383 /*
384 * Call blk_run_queue for all LUNs on the target, starting with
385 * current_sdev. We race with others (to set starget_sdev_user),
386 * but in most cases, we will be first. Ideally, each LU on the
387 * target would get some limited time or requests on the target.
388 */
389 scsi_kick_queue(current_sdev->request_queue);
390
391 spin_lock_irqsave(shost->host_lock, flags);
392 if (starget->starget_sdev_user)
393 goto out;
394 list_for_each_entry_safe(sdev, tmp, &starget->devices,
395 same_target_siblings) {
396 if (sdev == current_sdev)
397 continue;
398 if (scsi_device_get(sdev))
399 continue;
400
401 spin_unlock_irqrestore(shost->host_lock, flags);
402 scsi_kick_queue(sdev->request_queue);
403 spin_lock_irqsave(shost->host_lock, flags);
404
405 scsi_device_put(sdev);
406 }
407 out:
408 spin_unlock_irqrestore(shost->host_lock, flags);
409}
410
411static inline bool scsi_device_is_busy(struct scsi_device *sdev)
412{
413 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
414 return true;
415 if (atomic_read(&sdev->device_blocked) > 0)
416 return true;
417 return false;
418}
419
420static inline bool scsi_target_is_busy(struct scsi_target *starget)
421{
422 if (starget->can_queue > 0) {
423 if (atomic_read(&starget->target_busy) >= starget->can_queue)
424 return true;
425 if (atomic_read(&starget->target_blocked) > 0)
426 return true;
427 }
428 return false;
429}
430
431static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
432{
433 if (shost->can_queue > 0 &&
434 atomic_read(&shost->host_busy) >= shost->can_queue)
435 return true;
436 if (atomic_read(&shost->host_blocked) > 0)
437 return true;
438 if (shost->host_self_blocked)
439 return true;
440 return false;
441}
442
443static void scsi_starved_list_run(struct Scsi_Host *shost)
444{
445 LIST_HEAD(starved_list);
446 struct scsi_device *sdev;
447 unsigned long flags;
448
449 spin_lock_irqsave(shost->host_lock, flags);
450 list_splice_init(&shost->starved_list, &starved_list);
451
452 while (!list_empty(&starved_list)) {
453 struct request_queue *slq;
454
455 /*
456 * As long as shost is accepting commands and we have
457 * starved queues, call blk_run_queue. scsi_request_fn
458 * drops the queue_lock and can add us back to the
459 * starved_list.
460 *
461 * host_lock protects the starved_list and starved_entry.
462 * scsi_request_fn must get the host_lock before checking
463 * or modifying starved_list or starved_entry.
464 */
465 if (scsi_host_is_busy(shost))
466 break;
467
468 sdev = list_entry(starved_list.next,
469 struct scsi_device, starved_entry);
470 list_del_init(&sdev->starved_entry);
471 if (scsi_target_is_busy(scsi_target(sdev))) {
472 list_move_tail(&sdev->starved_entry,
473 &shost->starved_list);
474 continue;
475 }
476
477 /*
478 * Once we drop the host lock, a racing scsi_remove_device()
479 * call may remove the sdev from the starved list and destroy
480 * it and the queue. Mitigate by taking a reference to the
481 * queue and never touching the sdev again after we drop the
482 * host lock. Note: if __scsi_remove_device() invokes
483 * blk_cleanup_queue() before the queue is run from this
484 * function then blk_run_queue() will return immediately since
485 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
486 */
487 slq = sdev->request_queue;
488 if (!blk_get_queue(slq))
489 continue;
490 spin_unlock_irqrestore(shost->host_lock, flags);
491
492 scsi_kick_queue(slq);
493 blk_put_queue(slq);
494
495 spin_lock_irqsave(shost->host_lock, flags);
496 }
497 /* put any unprocessed entries back */
498 list_splice(&starved_list, &shost->starved_list);
499 spin_unlock_irqrestore(shost->host_lock, flags);
500}
501
502/*
503 * Function: scsi_run_queue()
504 *
505 * Purpose: Select a proper request queue to serve next
506 *
507 * Arguments: q - last request's queue
508 *
509 * Returns: Nothing
510 *
511 * Notes: The previous command was completely finished, start
512 * a new one if possible.
513 */
514static void scsi_run_queue(struct request_queue *q)
515{
516 struct scsi_device *sdev = q->queuedata;
517
518 if (scsi_target(sdev)->single_lun)
519 scsi_single_lun_run(sdev);
520 if (!list_empty(&sdev->host->starved_list))
521 scsi_starved_list_run(sdev->host);
522
523 blk_mq_run_hw_queues(q, false);
524}
525
526void scsi_requeue_run_queue(struct work_struct *work)
527{
528 struct scsi_device *sdev;
529 struct request_queue *q;
530
531 sdev = container_of(work, struct scsi_device, requeue_work);
532 q = sdev->request_queue;
533 scsi_run_queue(q);
534}
535
536void scsi_run_host_queues(struct Scsi_Host *shost)
537{
538 struct scsi_device *sdev;
539
540 shost_for_each_device(sdev, shost)
541 scsi_run_queue(sdev->request_queue);
542}
543
544static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
545{
546 if (!blk_rq_is_passthrough(cmd->request)) {
547 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
548
549 if (drv->uninit_command)
550 drv->uninit_command(cmd);
551 }
552}
553
554static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
555{
556 if (cmd->sdb.table.nents)
557 sg_free_table_chained(&cmd->sdb.table,
558 SCSI_INLINE_SG_CNT);
559 if (scsi_prot_sg_count(cmd))
560 sg_free_table_chained(&cmd->prot_sdb->table,
561 SCSI_INLINE_PROT_SG_CNT);
562}
563
564static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
565{
566 scsi_mq_free_sgtables(cmd);
567 scsi_uninit_cmd(cmd);
568 scsi_del_cmd_from_list(cmd);
569}
570
571/* Returns false when no more bytes to process, true if there are more */
572static bool scsi_end_request(struct request *req, blk_status_t error,
573 unsigned int bytes)
574{
575 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
576 struct scsi_device *sdev = cmd->device;
577 struct request_queue *q = sdev->request_queue;
578
579 if (blk_update_request(req, error, bytes))
580 return true;
581
582 if (blk_queue_add_random(q))
583 add_disk_randomness(req->rq_disk);
584
585 if (!blk_rq_is_scsi(req)) {
586 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
587 cmd->flags &= ~SCMD_INITIALIZED;
588 }
589
590 /*
591 * Calling rcu_barrier() is not necessary here because the
592 * SCSI error handler guarantees that the function called by
593 * call_rcu() has been called before scsi_end_request() is
594 * called.
595 */
596 destroy_rcu_head(&cmd->rcu);
597
598 /*
599 * In the MQ case the command gets freed by __blk_mq_end_request,
600 * so we have to do all cleanup that depends on it earlier.
601 *
602 * We also can't kick the queues from irq context, so we
603 * will have to defer it to a workqueue.
604 */
605 scsi_mq_uninit_cmd(cmd);
606
607 /*
608 * queue is still alive, so grab the ref for preventing it
609 * from being cleaned up during running queue.
610 */
611 percpu_ref_get(&q->q_usage_counter);
612
613 __blk_mq_end_request(req, error);
614
615 if (scsi_target(sdev)->single_lun ||
616 !list_empty(&sdev->host->starved_list))
617 kblockd_schedule_work(&sdev->requeue_work);
618 else
619 blk_mq_run_hw_queues(q, true);
620
621 percpu_ref_put(&q->q_usage_counter);
622 return false;
623}
624
625/**
626 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
627 * @cmd: SCSI command
628 * @result: scsi error code
629 *
630 * Translate a SCSI result code into a blk_status_t value. May reset the host
631 * byte of @cmd->result.
632 */
633static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
634{
635 switch (host_byte(result)) {
636 case DID_OK:
637 /*
638 * Also check the other bytes than the status byte in result
639 * to handle the case when a SCSI LLD sets result to
640 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
641 */
642 if (scsi_status_is_good(result) && (result & ~0xff) == 0)
643 return BLK_STS_OK;
644 return BLK_STS_IOERR;
645 case DID_TRANSPORT_FAILFAST:
646 return BLK_STS_TRANSPORT;
647 case DID_TARGET_FAILURE:
648 set_host_byte(cmd, DID_OK);
649 return BLK_STS_TARGET;
650 case DID_NEXUS_FAILURE:
651 set_host_byte(cmd, DID_OK);
652 return BLK_STS_NEXUS;
653 case DID_ALLOC_FAILURE:
654 set_host_byte(cmd, DID_OK);
655 return BLK_STS_NOSPC;
656 case DID_MEDIUM_ERROR:
657 set_host_byte(cmd, DID_OK);
658 return BLK_STS_MEDIUM;
659 default:
660 return BLK_STS_IOERR;
661 }
662}
663
664/* Helper for scsi_io_completion() when "reprep" action required. */
665static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
666 struct request_queue *q)
667{
668 /* A new command will be prepared and issued. */
669 scsi_mq_requeue_cmd(cmd);
670}
671
672/* Helper for scsi_io_completion() when special action required. */
673static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
674{
675 struct request_queue *q = cmd->device->request_queue;
676 struct request *req = cmd->request;
677 int level = 0;
678 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
679 ACTION_DELAYED_RETRY} action;
680 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
681 struct scsi_sense_hdr sshdr;
682 bool sense_valid;
683 bool sense_current = true; /* false implies "deferred sense" */
684 blk_status_t blk_stat;
685
686 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
687 if (sense_valid)
688 sense_current = !scsi_sense_is_deferred(&sshdr);
689
690 blk_stat = scsi_result_to_blk_status(cmd, result);
691
692 if (host_byte(result) == DID_RESET) {
693 /* Third party bus reset or reset for error recovery
694 * reasons. Just retry the command and see what
695 * happens.
696 */
697 action = ACTION_RETRY;
698 } else if (sense_valid && sense_current) {
699 switch (sshdr.sense_key) {
700 case UNIT_ATTENTION:
701 if (cmd->device->removable) {
702 /* Detected disc change. Set a bit
703 * and quietly refuse further access.
704 */
705 cmd->device->changed = 1;
706 action = ACTION_FAIL;
707 } else {
708 /* Must have been a power glitch, or a
709 * bus reset. Could not have been a
710 * media change, so we just retry the
711 * command and see what happens.
712 */
713 action = ACTION_RETRY;
714 }
715 break;
716 case ILLEGAL_REQUEST:
717 /* If we had an ILLEGAL REQUEST returned, then
718 * we may have performed an unsupported
719 * command. The only thing this should be
720 * would be a ten byte read where only a six
721 * byte read was supported. Also, on a system
722 * where READ CAPACITY failed, we may have
723 * read past the end of the disk.
724 */
725 if ((cmd->device->use_10_for_rw &&
726 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
727 (cmd->cmnd[0] == READ_10 ||
728 cmd->cmnd[0] == WRITE_10)) {
729 /* This will issue a new 6-byte command. */
730 cmd->device->use_10_for_rw = 0;
731 action = ACTION_REPREP;
732 } else if (sshdr.asc == 0x10) /* DIX */ {
733 action = ACTION_FAIL;
734 blk_stat = BLK_STS_PROTECTION;
735 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
736 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
737 action = ACTION_FAIL;
738 blk_stat = BLK_STS_TARGET;
739 } else
740 action = ACTION_FAIL;
741 break;
742 case ABORTED_COMMAND:
743 action = ACTION_FAIL;
744 if (sshdr.asc == 0x10) /* DIF */
745 blk_stat = BLK_STS_PROTECTION;
746 break;
747 case NOT_READY:
748 /* If the device is in the process of becoming
749 * ready, or has a temporary blockage, retry.
750 */
751 if (sshdr.asc == 0x04) {
752 switch (sshdr.ascq) {
753 case 0x01: /* becoming ready */
754 case 0x04: /* format in progress */
755 case 0x05: /* rebuild in progress */
756 case 0x06: /* recalculation in progress */
757 case 0x07: /* operation in progress */
758 case 0x08: /* Long write in progress */
759 case 0x09: /* self test in progress */
760 case 0x14: /* space allocation in progress */
761 case 0x1a: /* start stop unit in progress */
762 case 0x1b: /* sanitize in progress */
763 case 0x1d: /* configuration in progress */
764 case 0x24: /* depopulation in progress */
765 action = ACTION_DELAYED_RETRY;
766 break;
767 default:
768 action = ACTION_FAIL;
769 break;
770 }
771 } else
772 action = ACTION_FAIL;
773 break;
774 case VOLUME_OVERFLOW:
775 /* See SSC3rXX or current. */
776 action = ACTION_FAIL;
777 break;
778 default:
779 action = ACTION_FAIL;
780 break;
781 }
782 } else
783 action = ACTION_FAIL;
784
785 if (action != ACTION_FAIL &&
786 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
787 action = ACTION_FAIL;
788
789 switch (action) {
790 case ACTION_FAIL:
791 /* Give up and fail the remainder of the request */
792 if (!(req->rq_flags & RQF_QUIET)) {
793 static DEFINE_RATELIMIT_STATE(_rs,
794 DEFAULT_RATELIMIT_INTERVAL,
795 DEFAULT_RATELIMIT_BURST);
796
797 if (unlikely(scsi_logging_level))
798 level =
799 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
800 SCSI_LOG_MLCOMPLETE_BITS);
801
802 /*
803 * if logging is enabled the failure will be printed
804 * in scsi_log_completion(), so avoid duplicate messages
805 */
806 if (!level && __ratelimit(&_rs)) {
807 scsi_print_result(cmd, NULL, FAILED);
808 if (driver_byte(result) == DRIVER_SENSE)
809 scsi_print_sense(cmd);
810 scsi_print_command(cmd);
811 }
812 }
813 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
814 return;
815 /*FALLTHRU*/
816 case ACTION_REPREP:
817 scsi_io_completion_reprep(cmd, q);
818 break;
819 case ACTION_RETRY:
820 /* Retry the same command immediately */
821 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
822 break;
823 case ACTION_DELAYED_RETRY:
824 /* Retry the same command after a delay */
825 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
826 break;
827 }
828}
829
830/*
831 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
832 * new result that may suppress further error checking. Also modifies
833 * *blk_statp in some cases.
834 */
835static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
836 blk_status_t *blk_statp)
837{
838 bool sense_valid;
839 bool sense_current = true; /* false implies "deferred sense" */
840 struct request *req = cmd->request;
841 struct scsi_sense_hdr sshdr;
842
843 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
844 if (sense_valid)
845 sense_current = !scsi_sense_is_deferred(&sshdr);
846
847 if (blk_rq_is_passthrough(req)) {
848 if (sense_valid) {
849 /*
850 * SG_IO wants current and deferred errors
851 */
852 scsi_req(req)->sense_len =
853 min(8 + cmd->sense_buffer[7],
854 SCSI_SENSE_BUFFERSIZE);
855 }
856 if (sense_current)
857 *blk_statp = scsi_result_to_blk_status(cmd, result);
858 } else if (blk_rq_bytes(req) == 0 && sense_current) {
859 /*
860 * Flush commands do not transfers any data, and thus cannot use
861 * good_bytes != blk_rq_bytes(req) as the signal for an error.
862 * This sets *blk_statp explicitly for the problem case.
863 */
864 *blk_statp = scsi_result_to_blk_status(cmd, result);
865 }
866 /*
867 * Recovered errors need reporting, but they're always treated as
868 * success, so fiddle the result code here. For passthrough requests
869 * we already took a copy of the original into sreq->result which
870 * is what gets returned to the user
871 */
872 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
873 bool do_print = true;
874 /*
875 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
876 * skip print since caller wants ATA registers. Only occurs
877 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
878 */
879 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
880 do_print = false;
881 else if (req->rq_flags & RQF_QUIET)
882 do_print = false;
883 if (do_print)
884 scsi_print_sense(cmd);
885 result = 0;
886 /* for passthrough, *blk_statp may be set */
887 *blk_statp = BLK_STS_OK;
888 }
889 /*
890 * Another corner case: the SCSI status byte is non-zero but 'good'.
891 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
892 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
893 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
894 * intermediate statuses (both obsolete in SAM-4) as good.
895 */
896 if (status_byte(result) && scsi_status_is_good(result)) {
897 result = 0;
898 *blk_statp = BLK_STS_OK;
899 }
900 return result;
901}
902
903/*
904 * Function: scsi_io_completion()
905 *
906 * Purpose: Completion processing for block device I/O requests.
907 *
908 * Arguments: cmd - command that is finished.
909 *
910 * Lock status: Assumed that no lock is held upon entry.
911 *
912 * Returns: Nothing
913 *
914 * Notes: We will finish off the specified number of sectors. If we
915 * are done, the command block will be released and the queue
916 * function will be goosed. If we are not done then we have to
917 * figure out what to do next:
918 *
919 * a) We can call scsi_requeue_command(). The request
920 * will be unprepared and put back on the queue. Then
921 * a new command will be created for it. This should
922 * be used if we made forward progress, or if we want
923 * to switch from READ(10) to READ(6) for example.
924 *
925 * b) We can call __scsi_queue_insert(). The request will
926 * be put back on the queue and retried using the same
927 * command as before, possibly after a delay.
928 *
929 * c) We can call scsi_end_request() with blk_stat other than
930 * BLK_STS_OK, to fail the remainder of the request.
931 */
932void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
933{
934 int result = cmd->result;
935 struct request_queue *q = cmd->device->request_queue;
936 struct request *req = cmd->request;
937 blk_status_t blk_stat = BLK_STS_OK;
938
939 if (unlikely(result)) /* a nz result may or may not be an error */
940 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
941
942 if (unlikely(blk_rq_is_passthrough(req))) {
943 /*
944 * scsi_result_to_blk_status may have reset the host_byte
945 */
946 scsi_req(req)->result = cmd->result;
947 }
948
949 /*
950 * Next deal with any sectors which we were able to correctly
951 * handle.
952 */
953 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
954 "%u sectors total, %d bytes done.\n",
955 blk_rq_sectors(req), good_bytes));
956
957 /*
958 * Next deal with any sectors which we were able to correctly
959 * handle. Failed, zero length commands always need to drop down
960 * to retry code. Fast path should return in this block.
961 */
962 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
963 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
964 return; /* no bytes remaining */
965 }
966
967 /* Kill remainder if no retries. */
968 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
969 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
970 WARN_ONCE(true,
971 "Bytes remaining after failed, no-retry command");
972 return;
973 }
974
975 /*
976 * If there had been no error, but we have leftover bytes in the
977 * requeues just queue the command up again.
978 */
979 if (likely(result == 0))
980 scsi_io_completion_reprep(cmd, q);
981 else
982 scsi_io_completion_action(cmd, result);
983}
984
985static blk_status_t scsi_init_sgtable(struct request *req,
986 struct scsi_data_buffer *sdb)
987{
988 int count;
989
990 /*
991 * If sg table allocation fails, requeue request later.
992 */
993 if (unlikely(sg_alloc_table_chained(&sdb->table,
994 blk_rq_nr_phys_segments(req), sdb->table.sgl,
995 SCSI_INLINE_SG_CNT)))
996 return BLK_STS_RESOURCE;
997
998 /*
999 * Next, walk the list, and fill in the addresses and sizes of
1000 * each segment.
1001 */
1002 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1003 BUG_ON(count > sdb->table.nents);
1004 sdb->table.nents = count;
1005 sdb->length = blk_rq_payload_bytes(req);
1006 return BLK_STS_OK;
1007}
1008
1009/*
1010 * Function: scsi_init_io()
1011 *
1012 * Purpose: SCSI I/O initialize function.
1013 *
1014 * Arguments: cmd - Command descriptor we wish to initialize
1015 *
1016 * Returns: BLK_STS_OK on success
1017 * BLK_STS_RESOURCE if the failure is retryable
1018 * BLK_STS_IOERR if the failure is fatal
1019 */
1020blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
1021{
1022 struct request *rq = cmd->request;
1023 blk_status_t ret;
1024
1025 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1026 return BLK_STS_IOERR;
1027
1028 ret = scsi_init_sgtable(rq, &cmd->sdb);
1029 if (ret)
1030 return ret;
1031
1032 if (blk_integrity_rq(rq)) {
1033 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1034 int ivecs, count;
1035
1036 if (WARN_ON_ONCE(!prot_sdb)) {
1037 /*
1038 * This can happen if someone (e.g. multipath)
1039 * queues a command to a device on an adapter
1040 * that does not support DIX.
1041 */
1042 ret = BLK_STS_IOERR;
1043 goto out_free_sgtables;
1044 }
1045
1046 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1047
1048 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1049 prot_sdb->table.sgl,
1050 SCSI_INLINE_PROT_SG_CNT)) {
1051 ret = BLK_STS_RESOURCE;
1052 goto out_free_sgtables;
1053 }
1054
1055 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1056 prot_sdb->table.sgl);
1057 BUG_ON(count > ivecs);
1058 BUG_ON(count > queue_max_integrity_segments(rq->q));
1059
1060 cmd->prot_sdb = prot_sdb;
1061 cmd->prot_sdb->table.nents = count;
1062 }
1063
1064 return BLK_STS_OK;
1065out_free_sgtables:
1066 scsi_mq_free_sgtables(cmd);
1067 return ret;
1068}
1069EXPORT_SYMBOL(scsi_init_io);
1070
1071/**
1072 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1073 * @rq: Request associated with the SCSI command to be initialized.
1074 *
1075 * This function initializes the members of struct scsi_cmnd that must be
1076 * initialized before request processing starts and that won't be
1077 * reinitialized if a SCSI command is requeued.
1078 *
1079 * Called from inside blk_get_request() for pass-through requests and from
1080 * inside scsi_init_command() for filesystem requests.
1081 */
1082static void scsi_initialize_rq(struct request *rq)
1083{
1084 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1085
1086 scsi_req_init(&cmd->req);
1087 init_rcu_head(&cmd->rcu);
1088 cmd->jiffies_at_alloc = jiffies;
1089 cmd->retries = 0;
1090}
1091
1092/*
1093 * Only called when the request isn't completed by SCSI, and not freed by
1094 * SCSI
1095 */
1096static void scsi_cleanup_rq(struct request *rq)
1097{
1098 if (rq->rq_flags & RQF_DONTPREP) {
1099 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1100 rq->rq_flags &= ~RQF_DONTPREP;
1101 }
1102}
1103
1104/* Add a command to the list used by the aacraid and dpt_i2o drivers */
1105void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
1106{
1107 struct scsi_device *sdev = cmd->device;
1108 struct Scsi_Host *shost = sdev->host;
1109 unsigned long flags;
1110
1111 if (shost->use_cmd_list) {
1112 spin_lock_irqsave(&sdev->list_lock, flags);
1113 list_add_tail(&cmd->list, &sdev->cmd_list);
1114 spin_unlock_irqrestore(&sdev->list_lock, flags);
1115 }
1116}
1117
1118/* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1119void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
1120{
1121 struct scsi_device *sdev = cmd->device;
1122 struct Scsi_Host *shost = sdev->host;
1123 unsigned long flags;
1124
1125 if (shost->use_cmd_list) {
1126 spin_lock_irqsave(&sdev->list_lock, flags);
1127 BUG_ON(list_empty(&cmd->list));
1128 list_del_init(&cmd->list);
1129 spin_unlock_irqrestore(&sdev->list_lock, flags);
1130 }
1131}
1132
1133/* Called after a request has been started. */
1134void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1135{
1136 void *buf = cmd->sense_buffer;
1137 void *prot = cmd->prot_sdb;
1138 struct request *rq = blk_mq_rq_from_pdu(cmd);
1139 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1140 unsigned long jiffies_at_alloc;
1141 int retries;
1142
1143 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1144 flags |= SCMD_INITIALIZED;
1145 scsi_initialize_rq(rq);
1146 }
1147
1148 jiffies_at_alloc = cmd->jiffies_at_alloc;
1149 retries = cmd->retries;
1150 /* zero out the cmd, except for the embedded scsi_request */
1151 memset((char *)cmd + sizeof(cmd->req), 0,
1152 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1153
1154 cmd->device = dev;
1155 cmd->sense_buffer = buf;
1156 cmd->prot_sdb = prot;
1157 cmd->flags = flags;
1158 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1159 cmd->jiffies_at_alloc = jiffies_at_alloc;
1160 cmd->retries = retries;
1161
1162 scsi_add_cmd_to_list(cmd);
1163}
1164
1165static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1166 struct request *req)
1167{
1168 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1169
1170 /*
1171 * Passthrough requests may transfer data, in which case they must
1172 * a bio attached to them. Or they might contain a SCSI command
1173 * that does not transfer data, in which case they may optionally
1174 * submit a request without an attached bio.
1175 */
1176 if (req->bio) {
1177 blk_status_t ret = scsi_init_io(cmd);
1178 if (unlikely(ret != BLK_STS_OK))
1179 return ret;
1180 } else {
1181 BUG_ON(blk_rq_bytes(req));
1182
1183 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1184 }
1185
1186 cmd->cmd_len = scsi_req(req)->cmd_len;
1187 cmd->cmnd = scsi_req(req)->cmd;
1188 cmd->transfersize = blk_rq_bytes(req);
1189 cmd->allowed = scsi_req(req)->retries;
1190 return BLK_STS_OK;
1191}
1192
1193/*
1194 * Setup a normal block command. These are simple request from filesystems
1195 * that still need to be translated to SCSI CDBs from the ULD.
1196 */
1197static blk_status_t scsi_setup_fs_cmnd(struct scsi_device *sdev,
1198 struct request *req)
1199{
1200 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1201
1202 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1203 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1204 if (ret != BLK_STS_OK)
1205 return ret;
1206 }
1207
1208 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1209 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1210 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1211}
1212
1213static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
1214 struct request *req)
1215{
1216 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1217
1218 if (!blk_rq_bytes(req))
1219 cmd->sc_data_direction = DMA_NONE;
1220 else if (rq_data_dir(req) == WRITE)
1221 cmd->sc_data_direction = DMA_TO_DEVICE;
1222 else
1223 cmd->sc_data_direction = DMA_FROM_DEVICE;
1224
1225 if (blk_rq_is_scsi(req))
1226 return scsi_setup_scsi_cmnd(sdev, req);
1227 else
1228 return scsi_setup_fs_cmnd(sdev, req);
1229}
1230
1231static blk_status_t
1232scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1233{
1234 switch (sdev->sdev_state) {
1235 case SDEV_OFFLINE:
1236 case SDEV_TRANSPORT_OFFLINE:
1237 /*
1238 * If the device is offline we refuse to process any
1239 * commands. The device must be brought online
1240 * before trying any recovery commands.
1241 */
1242 sdev_printk(KERN_ERR, sdev,
1243 "rejecting I/O to offline device\n");
1244 return BLK_STS_IOERR;
1245 case SDEV_DEL:
1246 /*
1247 * If the device is fully deleted, we refuse to
1248 * process any commands as well.
1249 */
1250 sdev_printk(KERN_ERR, sdev,
1251 "rejecting I/O to dead device\n");
1252 return BLK_STS_IOERR;
1253 case SDEV_BLOCK:
1254 case SDEV_CREATED_BLOCK:
1255 return BLK_STS_RESOURCE;
1256 case SDEV_QUIESCE:
1257 /*
1258 * If the devices is blocked we defer normal commands.
1259 */
1260 if (req && !(req->rq_flags & RQF_PREEMPT))
1261 return BLK_STS_RESOURCE;
1262 return BLK_STS_OK;
1263 default:
1264 /*
1265 * For any other not fully online state we only allow
1266 * special commands. In particular any user initiated
1267 * command is not allowed.
1268 */
1269 if (req && !(req->rq_flags & RQF_PREEMPT))
1270 return BLK_STS_IOERR;
1271 return BLK_STS_OK;
1272 }
1273}
1274
1275/*
1276 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1277 * return 0.
1278 *
1279 * Called with the queue_lock held.
1280 */
1281static inline int scsi_dev_queue_ready(struct request_queue *q,
1282 struct scsi_device *sdev)
1283{
1284 unsigned int busy;
1285
1286 busy = atomic_inc_return(&sdev->device_busy) - 1;
1287 if (atomic_read(&sdev->device_blocked)) {
1288 if (busy)
1289 goto out_dec;
1290
1291 /*
1292 * unblock after device_blocked iterates to zero
1293 */
1294 if (atomic_dec_return(&sdev->device_blocked) > 0)
1295 goto out_dec;
1296 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1297 "unblocking device at zero depth\n"));
1298 }
1299
1300 if (busy >= sdev->queue_depth)
1301 goto out_dec;
1302
1303 return 1;
1304out_dec:
1305 atomic_dec(&sdev->device_busy);
1306 return 0;
1307}
1308
1309/*
1310 * scsi_target_queue_ready: checks if there we can send commands to target
1311 * @sdev: scsi device on starget to check.
1312 */
1313static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1314 struct scsi_device *sdev)
1315{
1316 struct scsi_target *starget = scsi_target(sdev);
1317 unsigned int busy;
1318
1319 if (starget->single_lun) {
1320 spin_lock_irq(shost->host_lock);
1321 if (starget->starget_sdev_user &&
1322 starget->starget_sdev_user != sdev) {
1323 spin_unlock_irq(shost->host_lock);
1324 return 0;
1325 }
1326 starget->starget_sdev_user = sdev;
1327 spin_unlock_irq(shost->host_lock);
1328 }
1329
1330 if (starget->can_queue <= 0)
1331 return 1;
1332
1333 busy = atomic_inc_return(&starget->target_busy) - 1;
1334 if (atomic_read(&starget->target_blocked) > 0) {
1335 if (busy)
1336 goto starved;
1337
1338 /*
1339 * unblock after target_blocked iterates to zero
1340 */
1341 if (atomic_dec_return(&starget->target_blocked) > 0)
1342 goto out_dec;
1343
1344 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1345 "unblocking target at zero depth\n"));
1346 }
1347
1348 if (busy >= starget->can_queue)
1349 goto starved;
1350
1351 return 1;
1352
1353starved:
1354 spin_lock_irq(shost->host_lock);
1355 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1356 spin_unlock_irq(shost->host_lock);
1357out_dec:
1358 if (starget->can_queue > 0)
1359 atomic_dec(&starget->target_busy);
1360 return 0;
1361}
1362
1363/*
1364 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1365 * return 0. We must end up running the queue again whenever 0 is
1366 * returned, else IO can hang.
1367 */
1368static inline int scsi_host_queue_ready(struct request_queue *q,
1369 struct Scsi_Host *shost,
1370 struct scsi_device *sdev)
1371{
1372 unsigned int busy;
1373
1374 if (scsi_host_in_recovery(shost))
1375 return 0;
1376
1377 busy = atomic_inc_return(&shost->host_busy) - 1;
1378 if (atomic_read(&shost->host_blocked) > 0) {
1379 if (busy)
1380 goto starved;
1381
1382 /*
1383 * unblock after host_blocked iterates to zero
1384 */
1385 if (atomic_dec_return(&shost->host_blocked) > 0)
1386 goto out_dec;
1387
1388 SCSI_LOG_MLQUEUE(3,
1389 shost_printk(KERN_INFO, shost,
1390 "unblocking host at zero depth\n"));
1391 }
1392
1393 if (shost->can_queue > 0 && busy >= shost->can_queue)
1394 goto starved;
1395 if (shost->host_self_blocked)
1396 goto starved;
1397
1398 /* We're OK to process the command, so we can't be starved */
1399 if (!list_empty(&sdev->starved_entry)) {
1400 spin_lock_irq(shost->host_lock);
1401 if (!list_empty(&sdev->starved_entry))
1402 list_del_init(&sdev->starved_entry);
1403 spin_unlock_irq(shost->host_lock);
1404 }
1405
1406 return 1;
1407
1408starved:
1409 spin_lock_irq(shost->host_lock);
1410 if (list_empty(&sdev->starved_entry))
1411 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1412 spin_unlock_irq(shost->host_lock);
1413out_dec:
1414 scsi_dec_host_busy(shost);
1415 return 0;
1416}
1417
1418/*
1419 * Busy state exporting function for request stacking drivers.
1420 *
1421 * For efficiency, no lock is taken to check the busy state of
1422 * shost/starget/sdev, since the returned value is not guaranteed and
1423 * may be changed after request stacking drivers call the function,
1424 * regardless of taking lock or not.
1425 *
1426 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1427 * needs to return 'not busy'. Otherwise, request stacking drivers
1428 * may hold requests forever.
1429 */
1430static bool scsi_mq_lld_busy(struct request_queue *q)
1431{
1432 struct scsi_device *sdev = q->queuedata;
1433 struct Scsi_Host *shost;
1434
1435 if (blk_queue_dying(q))
1436 return false;
1437
1438 shost = sdev->host;
1439
1440 /*
1441 * Ignore host/starget busy state.
1442 * Since block layer does not have a concept of fairness across
1443 * multiple queues, congestion of host/starget needs to be handled
1444 * in SCSI layer.
1445 */
1446 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1447 return true;
1448
1449 return false;
1450}
1451
1452static void scsi_softirq_done(struct request *rq)
1453{
1454 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1455 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1456 int disposition;
1457
1458 INIT_LIST_HEAD(&cmd->eh_entry);
1459
1460 atomic_inc(&cmd->device->iodone_cnt);
1461 if (cmd->result)
1462 atomic_inc(&cmd->device->ioerr_cnt);
1463
1464 disposition = scsi_decide_disposition(cmd);
1465 if (disposition != SUCCESS &&
1466 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1467 scmd_printk(KERN_ERR, cmd,
1468 "timing out command, waited %lus\n",
1469 wait_for/HZ);
1470 disposition = SUCCESS;
1471 }
1472
1473 scsi_log_completion(cmd, disposition);
1474
1475 switch (disposition) {
1476 case SUCCESS:
1477 scsi_finish_command(cmd);
1478 break;
1479 case NEEDS_RETRY:
1480 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1481 break;
1482 case ADD_TO_MLQUEUE:
1483 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1484 break;
1485 default:
1486 scsi_eh_scmd_add(cmd);
1487 break;
1488 }
1489}
1490
1491/**
1492 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1493 * @cmd: command block we are dispatching.
1494 *
1495 * Return: nonzero return request was rejected and device's queue needs to be
1496 * plugged.
1497 */
1498static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1499{
1500 struct Scsi_Host *host = cmd->device->host;
1501 int rtn = 0;
1502
1503 atomic_inc(&cmd->device->iorequest_cnt);
1504
1505 /* check if the device is still usable */
1506 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1507 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1508 * returns an immediate error upwards, and signals
1509 * that the device is no longer present */
1510 cmd->result = DID_NO_CONNECT << 16;
1511 goto done;
1512 }
1513
1514 /* Check to see if the scsi lld made this device blocked. */
1515 if (unlikely(scsi_device_blocked(cmd->device))) {
1516 /*
1517 * in blocked state, the command is just put back on
1518 * the device queue. The suspend state has already
1519 * blocked the queue so future requests should not
1520 * occur until the device transitions out of the
1521 * suspend state.
1522 */
1523 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1524 "queuecommand : device blocked\n"));
1525 return SCSI_MLQUEUE_DEVICE_BUSY;
1526 }
1527
1528 /* Store the LUN value in cmnd, if needed. */
1529 if (cmd->device->lun_in_cdb)
1530 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1531 (cmd->device->lun << 5 & 0xe0);
1532
1533 scsi_log_send(cmd);
1534
1535 /*
1536 * Before we queue this command, check if the command
1537 * length exceeds what the host adapter can handle.
1538 */
1539 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1540 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1541 "queuecommand : command too long. "
1542 "cdb_size=%d host->max_cmd_len=%d\n",
1543 cmd->cmd_len, cmd->device->host->max_cmd_len));
1544 cmd->result = (DID_ABORT << 16);
1545 goto done;
1546 }
1547
1548 if (unlikely(host->shost_state == SHOST_DEL)) {
1549 cmd->result = (DID_NO_CONNECT << 16);
1550 goto done;
1551
1552 }
1553
1554 trace_scsi_dispatch_cmd_start(cmd);
1555 rtn = host->hostt->queuecommand(host, cmd);
1556 if (rtn) {
1557 trace_scsi_dispatch_cmd_error(cmd, rtn);
1558 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1559 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1560 rtn = SCSI_MLQUEUE_HOST_BUSY;
1561
1562 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1563 "queuecommand : request rejected\n"));
1564 }
1565
1566 return rtn;
1567 done:
1568 cmd->scsi_done(cmd);
1569 return 0;
1570}
1571
1572/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1573static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1574{
1575 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1576 sizeof(struct scatterlist);
1577}
1578
1579static blk_status_t scsi_mq_prep_fn(struct request *req)
1580{
1581 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1582 struct scsi_device *sdev = req->q->queuedata;
1583 struct Scsi_Host *shost = sdev->host;
1584 struct scatterlist *sg;
1585
1586 scsi_init_command(sdev, cmd);
1587
1588 cmd->request = req;
1589 cmd->tag = req->tag;
1590 cmd->prot_op = SCSI_PROT_NORMAL;
1591
1592 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1593 cmd->sdb.table.sgl = sg;
1594
1595 if (scsi_host_get_prot(shost)) {
1596 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1597
1598 cmd->prot_sdb->table.sgl =
1599 (struct scatterlist *)(cmd->prot_sdb + 1);
1600 }
1601
1602 blk_mq_start_request(req);
1603
1604 return scsi_setup_cmnd(sdev, req);
1605}
1606
1607static void scsi_mq_done(struct scsi_cmnd *cmd)
1608{
1609 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1610 return;
1611 trace_scsi_dispatch_cmd_done(cmd);
1612
1613 /*
1614 * If the block layer didn't complete the request due to a timeout
1615 * injection, scsi must clear its internal completed state so that the
1616 * timeout handler will see it needs to escalate its own error
1617 * recovery.
1618 */
1619 if (unlikely(!blk_mq_complete_request(cmd->request)))
1620 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1621}
1622
1623static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1624{
1625 struct request_queue *q = hctx->queue;
1626 struct scsi_device *sdev = q->queuedata;
1627
1628 atomic_dec(&sdev->device_busy);
1629}
1630
1631static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1632{
1633 struct request_queue *q = hctx->queue;
1634 struct scsi_device *sdev = q->queuedata;
1635
1636 if (scsi_dev_queue_ready(q, sdev))
1637 return true;
1638
1639 if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
1640 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
1641 return false;
1642}
1643
1644static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1645 const struct blk_mq_queue_data *bd)
1646{
1647 struct request *req = bd->rq;
1648 struct request_queue *q = req->q;
1649 struct scsi_device *sdev = q->queuedata;
1650 struct Scsi_Host *shost = sdev->host;
1651 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1652 blk_status_t ret;
1653 int reason;
1654
1655 /*
1656 * If the device is not in running state we will reject some or all
1657 * commands.
1658 */
1659 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1660 ret = scsi_prep_state_check(sdev, req);
1661 if (ret != BLK_STS_OK)
1662 goto out_put_budget;
1663 }
1664
1665 ret = BLK_STS_RESOURCE;
1666 if (!scsi_target_queue_ready(shost, sdev))
1667 goto out_put_budget;
1668 if (!scsi_host_queue_ready(q, shost, sdev))
1669 goto out_dec_target_busy;
1670
1671 if (!(req->rq_flags & RQF_DONTPREP)) {
1672 ret = scsi_mq_prep_fn(req);
1673 if (ret != BLK_STS_OK)
1674 goto out_dec_host_busy;
1675 req->rq_flags |= RQF_DONTPREP;
1676 } else {
1677 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1678 blk_mq_start_request(req);
1679 }
1680
1681 cmd->flags &= SCMD_PRESERVED_FLAGS;
1682 if (sdev->simple_tags)
1683 cmd->flags |= SCMD_TAGGED;
1684 if (bd->last)
1685 cmd->flags |= SCMD_LAST;
1686
1687 scsi_init_cmd_errh(cmd);
1688 cmd->scsi_done = scsi_mq_done;
1689
1690 reason = scsi_dispatch_cmd(cmd);
1691 if (reason) {
1692 scsi_set_blocked(cmd, reason);
1693 ret = BLK_STS_RESOURCE;
1694 goto out_dec_host_busy;
1695 }
1696
1697 return BLK_STS_OK;
1698
1699out_dec_host_busy:
1700 scsi_dec_host_busy(shost);
1701out_dec_target_busy:
1702 if (scsi_target(sdev)->can_queue > 0)
1703 atomic_dec(&scsi_target(sdev)->target_busy);
1704out_put_budget:
1705 scsi_mq_put_budget(hctx);
1706 switch (ret) {
1707 case BLK_STS_OK:
1708 break;
1709 case BLK_STS_RESOURCE:
1710 if (atomic_read(&sdev->device_busy) ||
1711 scsi_device_blocked(sdev))
1712 ret = BLK_STS_DEV_RESOURCE;
1713 break;
1714 default:
1715 if (unlikely(!scsi_device_online(sdev)))
1716 scsi_req(req)->result = DID_NO_CONNECT << 16;
1717 else
1718 scsi_req(req)->result = DID_ERROR << 16;
1719 /*
1720 * Make sure to release all allocated resources when
1721 * we hit an error, as we will never see this command
1722 * again.
1723 */
1724 if (req->rq_flags & RQF_DONTPREP)
1725 scsi_mq_uninit_cmd(cmd);
1726 break;
1727 }
1728 return ret;
1729}
1730
1731static enum blk_eh_timer_return scsi_timeout(struct request *req,
1732 bool reserved)
1733{
1734 if (reserved)
1735 return BLK_EH_RESET_TIMER;
1736 return scsi_times_out(req);
1737}
1738
1739static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1740 unsigned int hctx_idx, unsigned int numa_node)
1741{
1742 struct Scsi_Host *shost = set->driver_data;
1743 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1744 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1745 struct scatterlist *sg;
1746
1747 if (unchecked_isa_dma)
1748 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1749 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1750 GFP_KERNEL, numa_node);
1751 if (!cmd->sense_buffer)
1752 return -ENOMEM;
1753 cmd->req.sense = cmd->sense_buffer;
1754
1755 if (scsi_host_get_prot(shost)) {
1756 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1757 shost->hostt->cmd_size;
1758 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1759 }
1760
1761 return 0;
1762}
1763
1764static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1765 unsigned int hctx_idx)
1766{
1767 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1768
1769 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1770 cmd->sense_buffer);
1771}
1772
1773static int scsi_map_queues(struct blk_mq_tag_set *set)
1774{
1775 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1776
1777 if (shost->hostt->map_queues)
1778 return shost->hostt->map_queues(shost);
1779 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1780}
1781
1782void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1783{
1784 struct device *dev = shost->dma_dev;
1785
1786 /*
1787 * this limit is imposed by hardware restrictions
1788 */
1789 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1790 SG_MAX_SEGMENTS));
1791
1792 if (scsi_host_prot_dma(shost)) {
1793 shost->sg_prot_tablesize =
1794 min_not_zero(shost->sg_prot_tablesize,
1795 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1796 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1797 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1798 }
1799
1800 if (dev->dma_mask) {
1801 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1802 dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1803 }
1804 blk_queue_max_hw_sectors(q, shost->max_sectors);
1805 if (shost->unchecked_isa_dma)
1806 blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1807 blk_queue_segment_boundary(q, shost->dma_boundary);
1808 dma_set_seg_boundary(dev, shost->dma_boundary);
1809
1810 blk_queue_max_segment_size(q, shost->max_segment_size);
1811 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1812 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1813
1814 /*
1815 * Set a reasonable default alignment: The larger of 32-byte (dword),
1816 * which is a common minimum for HBAs, and the minimum DMA alignment,
1817 * which is set by the platform.
1818 *
1819 * Devices that require a bigger alignment can increase it later.
1820 */
1821 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1822}
1823EXPORT_SYMBOL_GPL(__scsi_init_queue);
1824
1825static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1826 .get_budget = scsi_mq_get_budget,
1827 .put_budget = scsi_mq_put_budget,
1828 .queue_rq = scsi_queue_rq,
1829 .complete = scsi_softirq_done,
1830 .timeout = scsi_timeout,
1831#ifdef CONFIG_BLK_DEBUG_FS
1832 .show_rq = scsi_show_rq,
1833#endif
1834 .init_request = scsi_mq_init_request,
1835 .exit_request = scsi_mq_exit_request,
1836 .initialize_rq_fn = scsi_initialize_rq,
1837 .cleanup_rq = scsi_cleanup_rq,
1838 .busy = scsi_mq_lld_busy,
1839 .map_queues = scsi_map_queues,
1840};
1841
1842
1843static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1844{
1845 struct request_queue *q = hctx->queue;
1846 struct scsi_device *sdev = q->queuedata;
1847 struct Scsi_Host *shost = sdev->host;
1848
1849 shost->hostt->commit_rqs(shost, hctx->queue_num);
1850}
1851
1852static const struct blk_mq_ops scsi_mq_ops = {
1853 .get_budget = scsi_mq_get_budget,
1854 .put_budget = scsi_mq_put_budget,
1855 .queue_rq = scsi_queue_rq,
1856 .commit_rqs = scsi_commit_rqs,
1857 .complete = scsi_softirq_done,
1858 .timeout = scsi_timeout,
1859#ifdef CONFIG_BLK_DEBUG_FS
1860 .show_rq = scsi_show_rq,
1861#endif
1862 .init_request = scsi_mq_init_request,
1863 .exit_request = scsi_mq_exit_request,
1864 .initialize_rq_fn = scsi_initialize_rq,
1865 .cleanup_rq = scsi_cleanup_rq,
1866 .busy = scsi_mq_lld_busy,
1867 .map_queues = scsi_map_queues,
1868};
1869
1870struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1871{
1872 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1873 if (IS_ERR(sdev->request_queue))
1874 return NULL;
1875
1876 sdev->request_queue->queuedata = sdev;
1877 __scsi_init_queue(sdev->host, sdev->request_queue);
1878 blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1879 return sdev->request_queue;
1880}
1881
1882int scsi_mq_setup_tags(struct Scsi_Host *shost)
1883{
1884 unsigned int cmd_size, sgl_size;
1885
1886 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1887 scsi_mq_inline_sgl_size(shost));
1888 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1889 if (scsi_host_get_prot(shost))
1890 cmd_size += sizeof(struct scsi_data_buffer) +
1891 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1892
1893 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
1894 if (shost->hostt->commit_rqs)
1895 shost->tag_set.ops = &scsi_mq_ops;
1896 else
1897 shost->tag_set.ops = &scsi_mq_ops_no_commit;
1898 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
1899 shost->tag_set.queue_depth = shost->can_queue;
1900 shost->tag_set.cmd_size = cmd_size;
1901 shost->tag_set.numa_node = NUMA_NO_NODE;
1902 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1903 shost->tag_set.flags |=
1904 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1905 shost->tag_set.driver_data = shost;
1906
1907 return blk_mq_alloc_tag_set(&shost->tag_set);
1908}
1909
1910void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1911{
1912 blk_mq_free_tag_set(&shost->tag_set);
1913}
1914
1915/**
1916 * scsi_device_from_queue - return sdev associated with a request_queue
1917 * @q: The request queue to return the sdev from
1918 *
1919 * Return the sdev associated with a request queue or NULL if the
1920 * request_queue does not reference a SCSI device.
1921 */
1922struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1923{
1924 struct scsi_device *sdev = NULL;
1925
1926 if (q->mq_ops == &scsi_mq_ops_no_commit ||
1927 q->mq_ops == &scsi_mq_ops)
1928 sdev = q->queuedata;
1929 if (!sdev || !get_device(&sdev->sdev_gendev))
1930 sdev = NULL;
1931
1932 return sdev;
1933}
1934EXPORT_SYMBOL_GPL(scsi_device_from_queue);
1935
1936/*
1937 * Function: scsi_block_requests()
1938 *
1939 * Purpose: Utility function used by low-level drivers to prevent further
1940 * commands from being queued to the device.
1941 *
1942 * Arguments: shost - Host in question
1943 *
1944 * Returns: Nothing
1945 *
1946 * Lock status: No locks are assumed held.
1947 *
1948 * Notes: There is no timer nor any other means by which the requests
1949 * get unblocked other than the low-level driver calling
1950 * scsi_unblock_requests().
1951 */
1952void scsi_block_requests(struct Scsi_Host *shost)
1953{
1954 shost->host_self_blocked = 1;
1955}
1956EXPORT_SYMBOL(scsi_block_requests);
1957
1958/*
1959 * Function: scsi_unblock_requests()
1960 *
1961 * Purpose: Utility function used by low-level drivers to allow further
1962 * commands from being queued to the device.
1963 *
1964 * Arguments: shost - Host in question
1965 *
1966 * Returns: Nothing
1967 *
1968 * Lock status: No locks are assumed held.
1969 *
1970 * Notes: There is no timer nor any other means by which the requests
1971 * get unblocked other than the low-level driver calling
1972 * scsi_unblock_requests().
1973 *
1974 * This is done as an API function so that changes to the
1975 * internals of the scsi mid-layer won't require wholesale
1976 * changes to drivers that use this feature.
1977 */
1978void scsi_unblock_requests(struct Scsi_Host *shost)
1979{
1980 shost->host_self_blocked = 0;
1981 scsi_run_host_queues(shost);
1982}
1983EXPORT_SYMBOL(scsi_unblock_requests);
1984
1985int __init scsi_init_queue(void)
1986{
1987 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1988 sizeof(struct scsi_data_buffer),
1989 0, 0, NULL);
1990 if (!scsi_sdb_cache) {
1991 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
1992 return -ENOMEM;
1993 }
1994
1995 return 0;
1996}
1997
1998void scsi_exit_queue(void)
1999{
2000 kmem_cache_destroy(scsi_sense_cache);
2001 kmem_cache_destroy(scsi_sense_isadma_cache);
2002 kmem_cache_destroy(scsi_sdb_cache);
2003}
2004
2005/**
2006 * scsi_mode_select - issue a mode select
2007 * @sdev: SCSI device to be queried
2008 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2009 * @sp: Save page bit (0 == don't save, 1 == save)
2010 * @modepage: mode page being requested
2011 * @buffer: request buffer (may not be smaller than eight bytes)
2012 * @len: length of request buffer.
2013 * @timeout: command timeout
2014 * @retries: number of retries before failing
2015 * @data: returns a structure abstracting the mode header data
2016 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2017 * must be SCSI_SENSE_BUFFERSIZE big.
2018 *
2019 * Returns zero if successful; negative error number or scsi
2020 * status on error
2021 *
2022 */
2023int
2024scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2025 unsigned char *buffer, int len, int timeout, int retries,
2026 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2027{
2028 unsigned char cmd[10];
2029 unsigned char *real_buffer;
2030 int ret;
2031
2032 memset(cmd, 0, sizeof(cmd));
2033 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2034
2035 if (sdev->use_10_for_ms) {
2036 if (len > 65535)
2037 return -EINVAL;
2038 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2039 if (!real_buffer)
2040 return -ENOMEM;
2041 memcpy(real_buffer + 8, buffer, len);
2042 len += 8;
2043 real_buffer[0] = 0;
2044 real_buffer[1] = 0;
2045 real_buffer[2] = data->medium_type;
2046 real_buffer[3] = data->device_specific;
2047 real_buffer[4] = data->longlba ? 0x01 : 0;
2048 real_buffer[5] = 0;
2049 real_buffer[6] = data->block_descriptor_length >> 8;
2050 real_buffer[7] = data->block_descriptor_length;
2051
2052 cmd[0] = MODE_SELECT_10;
2053 cmd[7] = len >> 8;
2054 cmd[8] = len;
2055 } else {
2056 if (len > 255 || data->block_descriptor_length > 255 ||
2057 data->longlba)
2058 return -EINVAL;
2059
2060 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2061 if (!real_buffer)
2062 return -ENOMEM;
2063 memcpy(real_buffer + 4, buffer, len);
2064 len += 4;
2065 real_buffer[0] = 0;
2066 real_buffer[1] = data->medium_type;
2067 real_buffer[2] = data->device_specific;
2068 real_buffer[3] = data->block_descriptor_length;
2069
2070
2071 cmd[0] = MODE_SELECT;
2072 cmd[4] = len;
2073 }
2074
2075 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2076 sshdr, timeout, retries, NULL);
2077 kfree(real_buffer);
2078 return ret;
2079}
2080EXPORT_SYMBOL_GPL(scsi_mode_select);
2081
2082/**
2083 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2084 * @sdev: SCSI device to be queried
2085 * @dbd: set if mode sense will allow block descriptors to be returned
2086 * @modepage: mode page being requested
2087 * @buffer: request buffer (may not be smaller than eight bytes)
2088 * @len: length of request buffer.
2089 * @timeout: command timeout
2090 * @retries: number of retries before failing
2091 * @data: returns a structure abstracting the mode header data
2092 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2093 * must be SCSI_SENSE_BUFFERSIZE big.
2094 *
2095 * Returns zero if unsuccessful, or the header offset (either 4
2096 * or 8 depending on whether a six or ten byte command was
2097 * issued) if successful.
2098 */
2099int
2100scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2101 unsigned char *buffer, int len, int timeout, int retries,
2102 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2103{
2104 unsigned char cmd[12];
2105 int use_10_for_ms;
2106 int header_length;
2107 int result, retry_count = retries;
2108 struct scsi_sense_hdr my_sshdr;
2109
2110 memset(data, 0, sizeof(*data));
2111 memset(&cmd[0], 0, 12);
2112 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2113 cmd[2] = modepage;
2114
2115 /* caller might not be interested in sense, but we need it */
2116 if (!sshdr)
2117 sshdr = &my_sshdr;
2118
2119 retry:
2120 use_10_for_ms = sdev->use_10_for_ms;
2121
2122 if (use_10_for_ms) {
2123 if (len < 8)
2124 len = 8;
2125
2126 cmd[0] = MODE_SENSE_10;
2127 cmd[8] = len;
2128 header_length = 8;
2129 } else {
2130 if (len < 4)
2131 len = 4;
2132
2133 cmd[0] = MODE_SENSE;
2134 cmd[4] = len;
2135 header_length = 4;
2136 }
2137
2138 memset(buffer, 0, len);
2139
2140 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2141 sshdr, timeout, retries, NULL);
2142
2143 /* This code looks awful: what it's doing is making sure an
2144 * ILLEGAL REQUEST sense return identifies the actual command
2145 * byte as the problem. MODE_SENSE commands can return
2146 * ILLEGAL REQUEST if the code page isn't supported */
2147
2148 if (use_10_for_ms && !scsi_status_is_good(result) &&
2149 driver_byte(result) == DRIVER_SENSE) {
2150 if (scsi_sense_valid(sshdr)) {
2151 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2152 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2153 /*
2154 * Invalid command operation code
2155 */
2156 sdev->use_10_for_ms = 0;
2157 goto retry;
2158 }
2159 }
2160 }
2161
2162 if(scsi_status_is_good(result)) {
2163 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2164 (modepage == 6 || modepage == 8))) {
2165 /* Initio breakage? */
2166 header_length = 0;
2167 data->length = 13;
2168 data->medium_type = 0;
2169 data->device_specific = 0;
2170 data->longlba = 0;
2171 data->block_descriptor_length = 0;
2172 } else if(use_10_for_ms) {
2173 data->length = buffer[0]*256 + buffer[1] + 2;
2174 data->medium_type = buffer[2];
2175 data->device_specific = buffer[3];
2176 data->longlba = buffer[4] & 0x01;
2177 data->block_descriptor_length = buffer[6]*256
2178 + buffer[7];
2179 } else {
2180 data->length = buffer[0] + 1;
2181 data->medium_type = buffer[1];
2182 data->device_specific = buffer[2];
2183 data->block_descriptor_length = buffer[3];
2184 }
2185 data->header_length = header_length;
2186 } else if ((status_byte(result) == CHECK_CONDITION) &&
2187 scsi_sense_valid(sshdr) &&
2188 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2189 retry_count--;
2190 goto retry;
2191 }
2192
2193 return result;
2194}
2195EXPORT_SYMBOL(scsi_mode_sense);
2196
2197/**
2198 * scsi_test_unit_ready - test if unit is ready
2199 * @sdev: scsi device to change the state of.
2200 * @timeout: command timeout
2201 * @retries: number of retries before failing
2202 * @sshdr: outpout pointer for decoded sense information.
2203 *
2204 * Returns zero if unsuccessful or an error if TUR failed. For
2205 * removable media, UNIT_ATTENTION sets ->changed flag.
2206 **/
2207int
2208scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2209 struct scsi_sense_hdr *sshdr)
2210{
2211 char cmd[] = {
2212 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2213 };
2214 int result;
2215
2216 /* try to eat the UNIT_ATTENTION if there are enough retries */
2217 do {
2218 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2219 timeout, 1, NULL);
2220 if (sdev->removable && scsi_sense_valid(sshdr) &&
2221 sshdr->sense_key == UNIT_ATTENTION)
2222 sdev->changed = 1;
2223 } while (scsi_sense_valid(sshdr) &&
2224 sshdr->sense_key == UNIT_ATTENTION && --retries);
2225
2226 return result;
2227}
2228EXPORT_SYMBOL(scsi_test_unit_ready);
2229
2230/**
2231 * scsi_device_set_state - Take the given device through the device state model.
2232 * @sdev: scsi device to change the state of.
2233 * @state: state to change to.
2234 *
2235 * Returns zero if successful or an error if the requested
2236 * transition is illegal.
2237 */
2238int
2239scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2240{
2241 enum scsi_device_state oldstate = sdev->sdev_state;
2242
2243 if (state == oldstate)
2244 return 0;
2245
2246 switch (state) {
2247 case SDEV_CREATED:
2248 switch (oldstate) {
2249 case SDEV_CREATED_BLOCK:
2250 break;
2251 default:
2252 goto illegal;
2253 }
2254 break;
2255
2256 case SDEV_RUNNING:
2257 switch (oldstate) {
2258 case SDEV_CREATED:
2259 case SDEV_OFFLINE:
2260 case SDEV_TRANSPORT_OFFLINE:
2261 case SDEV_QUIESCE:
2262 case SDEV_BLOCK:
2263 break;
2264 default:
2265 goto illegal;
2266 }
2267 break;
2268
2269 case SDEV_QUIESCE:
2270 switch (oldstate) {
2271 case SDEV_RUNNING:
2272 case SDEV_OFFLINE:
2273 case SDEV_TRANSPORT_OFFLINE:
2274 break;
2275 default:
2276 goto illegal;
2277 }
2278 break;
2279
2280 case SDEV_OFFLINE:
2281 case SDEV_TRANSPORT_OFFLINE:
2282 switch (oldstate) {
2283 case SDEV_CREATED:
2284 case SDEV_RUNNING:
2285 case SDEV_QUIESCE:
2286 case SDEV_BLOCK:
2287 break;
2288 default:
2289 goto illegal;
2290 }
2291 break;
2292
2293 case SDEV_BLOCK:
2294 switch (oldstate) {
2295 case SDEV_RUNNING:
2296 case SDEV_CREATED_BLOCK:
2297 case SDEV_OFFLINE:
2298 break;
2299 default:
2300 goto illegal;
2301 }
2302 break;
2303
2304 case SDEV_CREATED_BLOCK:
2305 switch (oldstate) {
2306 case SDEV_CREATED:
2307 break;
2308 default:
2309 goto illegal;
2310 }
2311 break;
2312
2313 case SDEV_CANCEL:
2314 switch (oldstate) {
2315 case SDEV_CREATED:
2316 case SDEV_RUNNING:
2317 case SDEV_QUIESCE:
2318 case SDEV_OFFLINE:
2319 case SDEV_TRANSPORT_OFFLINE:
2320 break;
2321 default:
2322 goto illegal;
2323 }
2324 break;
2325
2326 case SDEV_DEL:
2327 switch (oldstate) {
2328 case SDEV_CREATED:
2329 case SDEV_RUNNING:
2330 case SDEV_OFFLINE:
2331 case SDEV_TRANSPORT_OFFLINE:
2332 case SDEV_CANCEL:
2333 case SDEV_BLOCK:
2334 case SDEV_CREATED_BLOCK:
2335 break;
2336 default:
2337 goto illegal;
2338 }
2339 break;
2340
2341 }
2342 sdev->sdev_state = state;
2343 return 0;
2344
2345 illegal:
2346 SCSI_LOG_ERROR_RECOVERY(1,
2347 sdev_printk(KERN_ERR, sdev,
2348 "Illegal state transition %s->%s",
2349 scsi_device_state_name(oldstate),
2350 scsi_device_state_name(state))
2351 );
2352 return -EINVAL;
2353}
2354EXPORT_SYMBOL(scsi_device_set_state);
2355
2356/**
2357 * sdev_evt_emit - emit a single SCSI device uevent
2358 * @sdev: associated SCSI device
2359 * @evt: event to emit
2360 *
2361 * Send a single uevent (scsi_event) to the associated scsi_device.
2362 */
2363static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2364{
2365 int idx = 0;
2366 char *envp[3];
2367
2368 switch (evt->evt_type) {
2369 case SDEV_EVT_MEDIA_CHANGE:
2370 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2371 break;
2372 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2373 scsi_rescan_device(&sdev->sdev_gendev);
2374 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2375 break;
2376 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2377 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2378 break;
2379 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2380 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2381 break;
2382 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2383 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2384 break;
2385 case SDEV_EVT_LUN_CHANGE_REPORTED:
2386 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2387 break;
2388 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2389 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2390 break;
2391 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2392 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2393 break;
2394 default:
2395 /* do nothing */
2396 break;
2397 }
2398
2399 envp[idx++] = NULL;
2400
2401 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2402}
2403
2404/**
2405 * sdev_evt_thread - send a uevent for each scsi event
2406 * @work: work struct for scsi_device
2407 *
2408 * Dispatch queued events to their associated scsi_device kobjects
2409 * as uevents.
2410 */
2411void scsi_evt_thread(struct work_struct *work)
2412{
2413 struct scsi_device *sdev;
2414 enum scsi_device_event evt_type;
2415 LIST_HEAD(event_list);
2416
2417 sdev = container_of(work, struct scsi_device, event_work);
2418
2419 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2420 if (test_and_clear_bit(evt_type, sdev->pending_events))
2421 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2422
2423 while (1) {
2424 struct scsi_event *evt;
2425 struct list_head *this, *tmp;
2426 unsigned long flags;
2427
2428 spin_lock_irqsave(&sdev->list_lock, flags);
2429 list_splice_init(&sdev->event_list, &event_list);
2430 spin_unlock_irqrestore(&sdev->list_lock, flags);
2431
2432 if (list_empty(&event_list))
2433 break;
2434
2435 list_for_each_safe(this, tmp, &event_list) {
2436 evt = list_entry(this, struct scsi_event, node);
2437 list_del(&evt->node);
2438 scsi_evt_emit(sdev, evt);
2439 kfree(evt);
2440 }
2441 }
2442}
2443
2444/**
2445 * sdev_evt_send - send asserted event to uevent thread
2446 * @sdev: scsi_device event occurred on
2447 * @evt: event to send
2448 *
2449 * Assert scsi device event asynchronously.
2450 */
2451void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2452{
2453 unsigned long flags;
2454
2455#if 0
2456 /* FIXME: currently this check eliminates all media change events
2457 * for polled devices. Need to update to discriminate between AN
2458 * and polled events */
2459 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2460 kfree(evt);
2461 return;
2462 }
2463#endif
2464
2465 spin_lock_irqsave(&sdev->list_lock, flags);
2466 list_add_tail(&evt->node, &sdev->event_list);
2467 schedule_work(&sdev->event_work);
2468 spin_unlock_irqrestore(&sdev->list_lock, flags);
2469}
2470EXPORT_SYMBOL_GPL(sdev_evt_send);
2471
2472/**
2473 * sdev_evt_alloc - allocate a new scsi event
2474 * @evt_type: type of event to allocate
2475 * @gfpflags: GFP flags for allocation
2476 *
2477 * Allocates and returns a new scsi_event.
2478 */
2479struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2480 gfp_t gfpflags)
2481{
2482 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2483 if (!evt)
2484 return NULL;
2485
2486 evt->evt_type = evt_type;
2487 INIT_LIST_HEAD(&evt->node);
2488
2489 /* evt_type-specific initialization, if any */
2490 switch (evt_type) {
2491 case SDEV_EVT_MEDIA_CHANGE:
2492 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2493 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2494 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2495 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2496 case SDEV_EVT_LUN_CHANGE_REPORTED:
2497 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2498 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2499 default:
2500 /* do nothing */
2501 break;
2502 }
2503
2504 return evt;
2505}
2506EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2507
2508/**
2509 * sdev_evt_send_simple - send asserted event to uevent thread
2510 * @sdev: scsi_device event occurred on
2511 * @evt_type: type of event to send
2512 * @gfpflags: GFP flags for allocation
2513 *
2514 * Assert scsi device event asynchronously, given an event type.
2515 */
2516void sdev_evt_send_simple(struct scsi_device *sdev,
2517 enum scsi_device_event evt_type, gfp_t gfpflags)
2518{
2519 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2520 if (!evt) {
2521 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2522 evt_type);
2523 return;
2524 }
2525
2526 sdev_evt_send(sdev, evt);
2527}
2528EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2529
2530/**
2531 * scsi_device_quiesce - Block user issued commands.
2532 * @sdev: scsi device to quiesce.
2533 *
2534 * This works by trying to transition to the SDEV_QUIESCE state
2535 * (which must be a legal transition). When the device is in this
2536 * state, only special requests will be accepted, all others will
2537 * be deferred. Since special requests may also be requeued requests,
2538 * a successful return doesn't guarantee the device will be
2539 * totally quiescent.
2540 *
2541 * Must be called with user context, may sleep.
2542 *
2543 * Returns zero if unsuccessful or an error if not.
2544 */
2545int
2546scsi_device_quiesce(struct scsi_device *sdev)
2547{
2548 struct request_queue *q = sdev->request_queue;
2549 int err;
2550
2551 /*
2552 * It is allowed to call scsi_device_quiesce() multiple times from
2553 * the same context but concurrent scsi_device_quiesce() calls are
2554 * not allowed.
2555 */
2556 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2557
2558 if (sdev->quiesced_by == current)
2559 return 0;
2560
2561 blk_set_pm_only(q);
2562
2563 blk_mq_freeze_queue(q);
2564 /*
2565 * Ensure that the effect of blk_set_pm_only() will be visible
2566 * for percpu_ref_tryget() callers that occur after the queue
2567 * unfreeze even if the queue was already frozen before this function
2568 * was called. See also https://lwn.net/Articles/573497/.
2569 */
2570 synchronize_rcu();
2571 blk_mq_unfreeze_queue(q);
2572
2573 mutex_lock(&sdev->state_mutex);
2574 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2575 if (err == 0)
2576 sdev->quiesced_by = current;
2577 else
2578 blk_clear_pm_only(q);
2579 mutex_unlock(&sdev->state_mutex);
2580
2581 return err;
2582}
2583EXPORT_SYMBOL(scsi_device_quiesce);
2584
2585/**
2586 * scsi_device_resume - Restart user issued commands to a quiesced device.
2587 * @sdev: scsi device to resume.
2588 *
2589 * Moves the device from quiesced back to running and restarts the
2590 * queues.
2591 *
2592 * Must be called with user context, may sleep.
2593 */
2594void scsi_device_resume(struct scsi_device *sdev)
2595{
2596 /* check if the device state was mutated prior to resume, and if
2597 * so assume the state is being managed elsewhere (for example
2598 * device deleted during suspend)
2599 */
2600 mutex_lock(&sdev->state_mutex);
2601 if (sdev->quiesced_by) {
2602 sdev->quiesced_by = NULL;
2603 blk_clear_pm_only(sdev->request_queue);
2604 }
2605 if (sdev->sdev_state == SDEV_QUIESCE)
2606 scsi_device_set_state(sdev, SDEV_RUNNING);
2607 mutex_unlock(&sdev->state_mutex);
2608}
2609EXPORT_SYMBOL(scsi_device_resume);
2610
2611static void
2612device_quiesce_fn(struct scsi_device *sdev, void *data)
2613{
2614 scsi_device_quiesce(sdev);
2615}
2616
2617void
2618scsi_target_quiesce(struct scsi_target *starget)
2619{
2620 starget_for_each_device(starget, NULL, device_quiesce_fn);
2621}
2622EXPORT_SYMBOL(scsi_target_quiesce);
2623
2624static void
2625device_resume_fn(struct scsi_device *sdev, void *data)
2626{
2627 scsi_device_resume(sdev);
2628}
2629
2630void
2631scsi_target_resume(struct scsi_target *starget)
2632{
2633 starget_for_each_device(starget, NULL, device_resume_fn);
2634}
2635EXPORT_SYMBOL(scsi_target_resume);
2636
2637/**
2638 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2639 * @sdev: device to block
2640 *
2641 * Pause SCSI command processing on the specified device. Does not sleep.
2642 *
2643 * Returns zero if successful or a negative error code upon failure.
2644 *
2645 * Notes:
2646 * This routine transitions the device to the SDEV_BLOCK state (which must be
2647 * a legal transition). When the device is in this state, command processing
2648 * is paused until the device leaves the SDEV_BLOCK state. See also
2649 * scsi_internal_device_unblock_nowait().
2650 */
2651int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2652{
2653 struct request_queue *q = sdev->request_queue;
2654 int err = 0;
2655
2656 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2657 if (err) {
2658 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2659
2660 if (err)
2661 return err;
2662 }
2663
2664 /*
2665 * The device has transitioned to SDEV_BLOCK. Stop the
2666 * block layer from calling the midlayer with this device's
2667 * request queue.
2668 */
2669 blk_mq_quiesce_queue_nowait(q);
2670 return 0;
2671}
2672EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2673
2674/**
2675 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2676 * @sdev: device to block
2677 *
2678 * Pause SCSI command processing on the specified device and wait until all
2679 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2680 *
2681 * Returns zero if successful or a negative error code upon failure.
2682 *
2683 * Note:
2684 * This routine transitions the device to the SDEV_BLOCK state (which must be
2685 * a legal transition). When the device is in this state, command processing
2686 * is paused until the device leaves the SDEV_BLOCK state. See also
2687 * scsi_internal_device_unblock().
2688 */
2689static int scsi_internal_device_block(struct scsi_device *sdev)
2690{
2691 struct request_queue *q = sdev->request_queue;
2692 int err;
2693
2694 mutex_lock(&sdev->state_mutex);
2695 err = scsi_internal_device_block_nowait(sdev);
2696 if (err == 0)
2697 blk_mq_quiesce_queue(q);
2698 mutex_unlock(&sdev->state_mutex);
2699
2700 return err;
2701}
2702
2703void scsi_start_queue(struct scsi_device *sdev)
2704{
2705 struct request_queue *q = sdev->request_queue;
2706
2707 blk_mq_unquiesce_queue(q);
2708}
2709
2710/**
2711 * scsi_internal_device_unblock_nowait - resume a device after a block request
2712 * @sdev: device to resume
2713 * @new_state: state to set the device to after unblocking
2714 *
2715 * Restart the device queue for a previously suspended SCSI device. Does not
2716 * sleep.
2717 *
2718 * Returns zero if successful or a negative error code upon failure.
2719 *
2720 * Notes:
2721 * This routine transitions the device to the SDEV_RUNNING state or to one of
2722 * the offline states (which must be a legal transition) allowing the midlayer
2723 * to goose the queue for this device.
2724 */
2725int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2726 enum scsi_device_state new_state)
2727{
2728 switch (new_state) {
2729 case SDEV_RUNNING:
2730 case SDEV_TRANSPORT_OFFLINE:
2731 break;
2732 default:
2733 return -EINVAL;
2734 }
2735
2736 /*
2737 * Try to transition the scsi device to SDEV_RUNNING or one of the
2738 * offlined states and goose the device queue if successful.
2739 */
2740 switch (sdev->sdev_state) {
2741 case SDEV_BLOCK:
2742 case SDEV_TRANSPORT_OFFLINE:
2743 sdev->sdev_state = new_state;
2744 break;
2745 case SDEV_CREATED_BLOCK:
2746 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2747 new_state == SDEV_OFFLINE)
2748 sdev->sdev_state = new_state;
2749 else
2750 sdev->sdev_state = SDEV_CREATED;
2751 break;
2752 case SDEV_CANCEL:
2753 case SDEV_OFFLINE:
2754 break;
2755 default:
2756 return -EINVAL;
2757 }
2758 scsi_start_queue(sdev);
2759
2760 return 0;
2761}
2762EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2763
2764/**
2765 * scsi_internal_device_unblock - resume a device after a block request
2766 * @sdev: device to resume
2767 * @new_state: state to set the device to after unblocking
2768 *
2769 * Restart the device queue for a previously suspended SCSI device. May sleep.
2770 *
2771 * Returns zero if successful or a negative error code upon failure.
2772 *
2773 * Notes:
2774 * This routine transitions the device to the SDEV_RUNNING state or to one of
2775 * the offline states (which must be a legal transition) allowing the midlayer
2776 * to goose the queue for this device.
2777 */
2778static int scsi_internal_device_unblock(struct scsi_device *sdev,
2779 enum scsi_device_state new_state)
2780{
2781 int ret;
2782
2783 mutex_lock(&sdev->state_mutex);
2784 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2785 mutex_unlock(&sdev->state_mutex);
2786
2787 return ret;
2788}
2789
2790static void
2791device_block(struct scsi_device *sdev, void *data)
2792{
2793 int ret;
2794
2795 ret = scsi_internal_device_block(sdev);
2796
2797 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2798 dev_name(&sdev->sdev_gendev), ret);
2799}
2800
2801static int
2802target_block(struct device *dev, void *data)
2803{
2804 if (scsi_is_target_device(dev))
2805 starget_for_each_device(to_scsi_target(dev), NULL,
2806 device_block);
2807 return 0;
2808}
2809
2810void
2811scsi_target_block(struct device *dev)
2812{
2813 if (scsi_is_target_device(dev))
2814 starget_for_each_device(to_scsi_target(dev), NULL,
2815 device_block);
2816 else
2817 device_for_each_child(dev, NULL, target_block);
2818}
2819EXPORT_SYMBOL_GPL(scsi_target_block);
2820
2821static void
2822device_unblock(struct scsi_device *sdev, void *data)
2823{
2824 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2825}
2826
2827static int
2828target_unblock(struct device *dev, void *data)
2829{
2830 if (scsi_is_target_device(dev))
2831 starget_for_each_device(to_scsi_target(dev), data,
2832 device_unblock);
2833 return 0;
2834}
2835
2836void
2837scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2838{
2839 if (scsi_is_target_device(dev))
2840 starget_for_each_device(to_scsi_target(dev), &new_state,
2841 device_unblock);
2842 else
2843 device_for_each_child(dev, &new_state, target_unblock);
2844}
2845EXPORT_SYMBOL_GPL(scsi_target_unblock);
2846
2847/**
2848 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2849 * @sgl: scatter-gather list
2850 * @sg_count: number of segments in sg
2851 * @offset: offset in bytes into sg, on return offset into the mapped area
2852 * @len: bytes to map, on return number of bytes mapped
2853 *
2854 * Returns virtual address of the start of the mapped page
2855 */
2856void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2857 size_t *offset, size_t *len)
2858{
2859 int i;
2860 size_t sg_len = 0, len_complete = 0;
2861 struct scatterlist *sg;
2862 struct page *page;
2863
2864 WARN_ON(!irqs_disabled());
2865
2866 for_each_sg(sgl, sg, sg_count, i) {
2867 len_complete = sg_len; /* Complete sg-entries */
2868 sg_len += sg->length;
2869 if (sg_len > *offset)
2870 break;
2871 }
2872
2873 if (unlikely(i == sg_count)) {
2874 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2875 "elements %d\n",
2876 __func__, sg_len, *offset, sg_count);
2877 WARN_ON(1);
2878 return NULL;
2879 }
2880
2881 /* Offset starting from the beginning of first page in this sg-entry */
2882 *offset = *offset - len_complete + sg->offset;
2883
2884 /* Assumption: contiguous pages can be accessed as "page + i" */
2885 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2886 *offset &= ~PAGE_MASK;
2887
2888 /* Bytes in this sg-entry from *offset to the end of the page */
2889 sg_len = PAGE_SIZE - *offset;
2890 if (*len > sg_len)
2891 *len = sg_len;
2892
2893 return kmap_atomic(page);
2894}
2895EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2896
2897/**
2898 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2899 * @virt: virtual address to be unmapped
2900 */
2901void scsi_kunmap_atomic_sg(void *virt)
2902{
2903 kunmap_atomic(virt);
2904}
2905EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2906
2907void sdev_disable_disk_events(struct scsi_device *sdev)
2908{
2909 atomic_inc(&sdev->disk_events_disable_depth);
2910}
2911EXPORT_SYMBOL(sdev_disable_disk_events);
2912
2913void sdev_enable_disk_events(struct scsi_device *sdev)
2914{
2915 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2916 return;
2917 atomic_dec(&sdev->disk_events_disable_depth);
2918}
2919EXPORT_SYMBOL(sdev_enable_disk_events);
2920
2921/**
2922 * scsi_vpd_lun_id - return a unique device identification
2923 * @sdev: SCSI device
2924 * @id: buffer for the identification
2925 * @id_len: length of the buffer
2926 *
2927 * Copies a unique device identification into @id based
2928 * on the information in the VPD page 0x83 of the device.
2929 * The string will be formatted as a SCSI name string.
2930 *
2931 * Returns the length of the identification or error on failure.
2932 * If the identifier is longer than the supplied buffer the actual
2933 * identifier length is returned and the buffer is not zero-padded.
2934 */
2935int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
2936{
2937 u8 cur_id_type = 0xff;
2938 u8 cur_id_size = 0;
2939 const unsigned char *d, *cur_id_str;
2940 const struct scsi_vpd *vpd_pg83;
2941 int id_size = -EINVAL;
2942
2943 rcu_read_lock();
2944 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
2945 if (!vpd_pg83) {
2946 rcu_read_unlock();
2947 return -ENXIO;
2948 }
2949
2950 /*
2951 * Look for the correct descriptor.
2952 * Order of preference for lun descriptor:
2953 * - SCSI name string
2954 * - NAA IEEE Registered Extended
2955 * - EUI-64 based 16-byte
2956 * - EUI-64 based 12-byte
2957 * - NAA IEEE Registered
2958 * - NAA IEEE Extended
2959 * - T10 Vendor ID
2960 * as longer descriptors reduce the likelyhood
2961 * of identification clashes.
2962 */
2963
2964 /* The id string must be at least 20 bytes + terminating NULL byte */
2965 if (id_len < 21) {
2966 rcu_read_unlock();
2967 return -EINVAL;
2968 }
2969
2970 memset(id, 0, id_len);
2971 d = vpd_pg83->data + 4;
2972 while (d < vpd_pg83->data + vpd_pg83->len) {
2973 /* Skip designators not referring to the LUN */
2974 if ((d[1] & 0x30) != 0x00)
2975 goto next_desig;
2976
2977 switch (d[1] & 0xf) {
2978 case 0x1:
2979 /* T10 Vendor ID */
2980 if (cur_id_size > d[3])
2981 break;
2982 /* Prefer anything */
2983 if (cur_id_type > 0x01 && cur_id_type != 0xff)
2984 break;
2985 cur_id_size = d[3];
2986 if (cur_id_size + 4 > id_len)
2987 cur_id_size = id_len - 4;
2988 cur_id_str = d + 4;
2989 cur_id_type = d[1] & 0xf;
2990 id_size = snprintf(id, id_len, "t10.%*pE",
2991 cur_id_size, cur_id_str);
2992 break;
2993 case 0x2:
2994 /* EUI-64 */
2995 if (cur_id_size > d[3])
2996 break;
2997 /* Prefer NAA IEEE Registered Extended */
2998 if (cur_id_type == 0x3 &&
2999 cur_id_size == d[3])
3000 break;
3001 cur_id_size = d[3];
3002 cur_id_str = d + 4;
3003 cur_id_type = d[1] & 0xf;
3004 switch (cur_id_size) {
3005 case 8:
3006 id_size = snprintf(id, id_len,
3007 "eui.%8phN",
3008 cur_id_str);
3009 break;
3010 case 12:
3011 id_size = snprintf(id, id_len,
3012 "eui.%12phN",
3013 cur_id_str);
3014 break;
3015 case 16:
3016 id_size = snprintf(id, id_len,
3017 "eui.%16phN",
3018 cur_id_str);
3019 break;
3020 default:
3021 cur_id_size = 0;
3022 break;
3023 }
3024 break;
3025 case 0x3:
3026 /* NAA */
3027 if (cur_id_size > d[3])
3028 break;
3029 cur_id_size = d[3];
3030 cur_id_str = d + 4;
3031 cur_id_type = d[1] & 0xf;
3032 switch (cur_id_size) {
3033 case 8:
3034 id_size = snprintf(id, id_len,
3035 "naa.%8phN",
3036 cur_id_str);
3037 break;
3038 case 16:
3039 id_size = snprintf(id, id_len,
3040 "naa.%16phN",
3041 cur_id_str);
3042 break;
3043 default:
3044 cur_id_size = 0;
3045 break;
3046 }
3047 break;
3048 case 0x8:
3049 /* SCSI name string */
3050 if (cur_id_size + 4 > d[3])
3051 break;
3052 /* Prefer others for truncated descriptor */
3053 if (cur_id_size && d[3] > id_len)
3054 break;
3055 cur_id_size = id_size = d[3];
3056 cur_id_str = d + 4;
3057 cur_id_type = d[1] & 0xf;
3058 if (cur_id_size >= id_len)
3059 cur_id_size = id_len - 1;
3060 memcpy(id, cur_id_str, cur_id_size);
3061 /* Decrease priority for truncated descriptor */
3062 if (cur_id_size != id_size)
3063 cur_id_size = 6;
3064 break;
3065 default:
3066 break;
3067 }
3068next_desig:
3069 d += d[3] + 4;
3070 }
3071 rcu_read_unlock();
3072
3073 return id_size;
3074}
3075EXPORT_SYMBOL(scsi_vpd_lun_id);
3076
3077/*
3078 * scsi_vpd_tpg_id - return a target port group identifier
3079 * @sdev: SCSI device
3080 *
3081 * Returns the Target Port Group identifier from the information
3082 * froom VPD page 0x83 of the device.
3083 *
3084 * Returns the identifier or error on failure.
3085 */
3086int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3087{
3088 const unsigned char *d;
3089 const struct scsi_vpd *vpd_pg83;
3090 int group_id = -EAGAIN, rel_port = -1;
3091
3092 rcu_read_lock();
3093 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3094 if (!vpd_pg83) {
3095 rcu_read_unlock();
3096 return -ENXIO;
3097 }
3098
3099 d = vpd_pg83->data + 4;
3100 while (d < vpd_pg83->data + vpd_pg83->len) {
3101 switch (d[1] & 0xf) {
3102 case 0x4:
3103 /* Relative target port */
3104 rel_port = get_unaligned_be16(&d[6]);
3105 break;
3106 case 0x5:
3107 /* Target port group */
3108 group_id = get_unaligned_be16(&d[6]);
3109 break;
3110 default:
3111 break;
3112 }
3113 d += d[3] + 4;
3114 }
3115 rcu_read_unlock();
3116
3117 if (group_id >= 0 && rel_id && rel_port != -1)
3118 *rel_id = rel_port;
3119
3120 return group_id;
3121}
3122EXPORT_SYMBOL(scsi_vpd_tpg_id);