2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
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.
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/init.h>
18 #include <linux/pci.h>
19 #include <linux/delay.h>
20 #include <linux/hardirq.h>
21 #include <linux/scatterlist.h>
22 #include <linux/blk-mq.h>
23 #include <linux/ratelimit.h>
24 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_driver.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_host.h>
33 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
34 #include <scsi/scsi_dh.h>
36 #include <trace/events/scsi.h>
38 #include "scsi_debugfs.h"
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
42 static struct kmem_cache
*scsi_sdb_cache
;
43 static struct kmem_cache
*scsi_sense_cache
;
44 static struct kmem_cache
*scsi_sense_isadma_cache
;
45 static DEFINE_MUTEX(scsi_sense_cache_mutex
);
47 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
);
49 static inline struct kmem_cache
*
50 scsi_select_sense_cache(bool unchecked_isa_dma
)
52 return unchecked_isa_dma
? scsi_sense_isadma_cache
: scsi_sense_cache
;
55 static void scsi_free_sense_buffer(bool unchecked_isa_dma
,
56 unsigned char *sense_buffer
)
58 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma
),
62 static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma
,
63 gfp_t gfp_mask
, int numa_node
)
65 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma
),
69 int scsi_init_sense_cache(struct Scsi_Host
*shost
)
71 struct kmem_cache
*cache
;
74 cache
= scsi_select_sense_cache(shost
->unchecked_isa_dma
);
78 mutex_lock(&scsi_sense_cache_mutex
);
79 if (shost
->unchecked_isa_dma
) {
80 scsi_sense_isadma_cache
=
81 kmem_cache_create("scsi_sense_cache(DMA)",
82 SCSI_SENSE_BUFFERSIZE
, 0,
83 SLAB_HWCACHE_ALIGN
| SLAB_CACHE_DMA
, NULL
);
84 if (!scsi_sense_isadma_cache
)
88 kmem_cache_create("scsi_sense_cache",
89 SCSI_SENSE_BUFFERSIZE
, 0, SLAB_HWCACHE_ALIGN
, NULL
);
90 if (!scsi_sense_cache
)
94 mutex_unlock(&scsi_sense_cache_mutex
);
99 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
100 * not change behaviour from the previous unplug mechanism, experimentation
101 * may prove this needs changing.
103 #define SCSI_QUEUE_DELAY 3
106 scsi_set_blocked(struct scsi_cmnd
*cmd
, int reason
)
108 struct Scsi_Host
*host
= cmd
->device
->host
;
109 struct scsi_device
*device
= cmd
->device
;
110 struct scsi_target
*starget
= scsi_target(device
);
113 * Set the appropriate busy bit for the device/host.
115 * If the host/device isn't busy, assume that something actually
116 * completed, and that we should be able to queue a command now.
118 * Note that the prior mid-layer assumption that any host could
119 * always queue at least one command is now broken. The mid-layer
120 * will implement a user specifiable stall (see
121 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
122 * if a command is requeued with no other commands outstanding
123 * either for the device or for the host.
126 case SCSI_MLQUEUE_HOST_BUSY
:
127 atomic_set(&host
->host_blocked
, host
->max_host_blocked
);
129 case SCSI_MLQUEUE_DEVICE_BUSY
:
130 case SCSI_MLQUEUE_EH_RETRY
:
131 atomic_set(&device
->device_blocked
,
132 device
->max_device_blocked
);
134 case SCSI_MLQUEUE_TARGET_BUSY
:
135 atomic_set(&starget
->target_blocked
,
136 starget
->max_target_blocked
);
141 static void scsi_mq_requeue_cmd(struct scsi_cmnd
*cmd
)
143 struct scsi_device
*sdev
= cmd
->device
;
145 if (cmd
->request
->rq_flags
& RQF_DONTPREP
) {
146 cmd
->request
->rq_flags
&= ~RQF_DONTPREP
;
147 scsi_mq_uninit_cmd(cmd
);
151 blk_mq_requeue_request(cmd
->request
, true);
152 put_device(&sdev
->sdev_gendev
);
156 * __scsi_queue_insert - private queue insertion
157 * @cmd: The SCSI command being requeued
158 * @reason: The reason for the requeue
159 * @unbusy: Whether the queue should be unbusied
161 * This is a private queue insertion. The public interface
162 * scsi_queue_insert() always assumes the queue should be unbusied
163 * because it's always called before the completion. This function is
164 * for a requeue after completion, which should only occur in this
167 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
169 struct scsi_device
*device
= cmd
->device
;
170 struct request_queue
*q
= device
->request_queue
;
173 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO
, cmd
,
174 "Inserting command %p into mlqueue\n", cmd
));
176 scsi_set_blocked(cmd
, reason
);
179 * Decrement the counters, since these commands are no longer
180 * active on the host/device.
183 scsi_device_unbusy(device
);
186 * Requeue this command. It will go before all other commands
187 * that are already in the queue. Schedule requeue work under
188 * lock such that the kblockd_schedule_work() call happens
189 * before blk_cleanup_queue() finishes.
193 scsi_mq_requeue_cmd(cmd
);
196 spin_lock_irqsave(q
->queue_lock
, flags
);
197 blk_requeue_request(q
, cmd
->request
);
198 kblockd_schedule_work(&device
->requeue_work
);
199 spin_unlock_irqrestore(q
->queue_lock
, flags
);
203 * Function: scsi_queue_insert()
205 * Purpose: Insert a command in the midlevel queue.
207 * Arguments: cmd - command that we are adding to queue.
208 * reason - why we are inserting command to queue.
210 * Lock status: Assumed that lock is not held upon entry.
214 * Notes: We do this for one of two cases. Either the host is busy
215 * and it cannot accept any more commands for the time being,
216 * or the device returned QUEUE_FULL and can accept no more
218 * Notes: This could be called either from an interrupt context or a
219 * normal process context.
221 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
223 __scsi_queue_insert(cmd
, reason
, 1);
228 * scsi_execute - insert request and wait for the result
231 * @data_direction: data direction
232 * @buffer: data buffer
233 * @bufflen: len of buffer
234 * @sense: optional sense buffer
235 * @sshdr: optional decoded sense header
236 * @timeout: request timeout in seconds
237 * @retries: number of times to retry request
238 * @flags: flags for ->cmd_flags
239 * @rq_flags: flags for ->rq_flags
240 * @resid: optional residual length
242 * Returns the scsi_cmnd result field if a command was executed, or a negative
243 * Linux error code if we didn't get that far.
245 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
246 int data_direction
, void *buffer
, unsigned bufflen
,
247 unsigned char *sense
, struct scsi_sense_hdr
*sshdr
,
248 int timeout
, int retries
, u64 flags
, req_flags_t rq_flags
,
252 struct scsi_request
*rq
;
253 int ret
= DRIVER_ERROR
<< 24;
255 req
= blk_get_request(sdev
->request_queue
,
256 data_direction
== DMA_TO_DEVICE
?
257 REQ_OP_SCSI_OUT
: REQ_OP_SCSI_IN
, __GFP_RECLAIM
);
262 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
263 buffer
, bufflen
, __GFP_RECLAIM
))
266 rq
->cmd_len
= COMMAND_SIZE(cmd
[0]);
267 memcpy(rq
->cmd
, cmd
, rq
->cmd_len
);
268 rq
->retries
= retries
;
269 req
->timeout
= timeout
;
270 req
->cmd_flags
|= flags
;
271 req
->rq_flags
|= rq_flags
| RQF_QUIET
| RQF_PREEMPT
;
274 * head injection *required* here otherwise quiesce won't work
276 blk_execute_rq(req
->q
, NULL
, req
, 1);
279 * Some devices (USB mass-storage in particular) may transfer
280 * garbage data together with a residue indicating that the data
281 * is invalid. Prevent the garbage from being misinterpreted
282 * and prevent security leaks by zeroing out the excess data.
284 if (unlikely(rq
->resid_len
> 0 && rq
->resid_len
<= bufflen
))
285 memset(buffer
+ (bufflen
- rq
->resid_len
), 0, rq
->resid_len
);
288 *resid
= rq
->resid_len
;
289 if (sense
&& rq
->sense_len
)
290 memcpy(sense
, rq
->sense
, SCSI_SENSE_BUFFERSIZE
);
292 scsi_normalize_sense(rq
->sense
, rq
->sense_len
, sshdr
);
295 blk_put_request(req
);
299 EXPORT_SYMBOL(scsi_execute
);
302 * Function: scsi_init_cmd_errh()
304 * Purpose: Initialize cmd fields related to error handling.
306 * Arguments: cmd - command that is ready to be queued.
308 * Notes: This function has the job of initializing a number of
309 * fields related to error handling. Typically this will
310 * be called once for each command, as required.
312 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
314 cmd
->serial_number
= 0;
315 scsi_set_resid(cmd
, 0);
316 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
317 if (cmd
->cmd_len
== 0)
318 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
321 void scsi_device_unbusy(struct scsi_device
*sdev
)
323 struct Scsi_Host
*shost
= sdev
->host
;
324 struct scsi_target
*starget
= scsi_target(sdev
);
327 atomic_dec(&shost
->host_busy
);
328 if (starget
->can_queue
> 0)
329 atomic_dec(&starget
->target_busy
);
331 if (unlikely(scsi_host_in_recovery(shost
) &&
332 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
333 spin_lock_irqsave(shost
->host_lock
, flags
);
334 scsi_eh_wakeup(shost
);
335 spin_unlock_irqrestore(shost
->host_lock
, flags
);
338 atomic_dec(&sdev
->device_busy
);
341 static void scsi_kick_queue(struct request_queue
*q
)
344 blk_mq_start_hw_queues(q
);
350 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
351 * and call blk_run_queue for all the scsi_devices on the target -
352 * including current_sdev first.
354 * Called with *no* scsi locks held.
356 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
358 struct Scsi_Host
*shost
= current_sdev
->host
;
359 struct scsi_device
*sdev
, *tmp
;
360 struct scsi_target
*starget
= scsi_target(current_sdev
);
363 spin_lock_irqsave(shost
->host_lock
, flags
);
364 starget
->starget_sdev_user
= NULL
;
365 spin_unlock_irqrestore(shost
->host_lock
, flags
);
368 * Call blk_run_queue for all LUNs on the target, starting with
369 * current_sdev. We race with others (to set starget_sdev_user),
370 * but in most cases, we will be first. Ideally, each LU on the
371 * target would get some limited time or requests on the target.
373 scsi_kick_queue(current_sdev
->request_queue
);
375 spin_lock_irqsave(shost
->host_lock
, flags
);
376 if (starget
->starget_sdev_user
)
378 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
379 same_target_siblings
) {
380 if (sdev
== current_sdev
)
382 if (scsi_device_get(sdev
))
385 spin_unlock_irqrestore(shost
->host_lock
, flags
);
386 scsi_kick_queue(sdev
->request_queue
);
387 spin_lock_irqsave(shost
->host_lock
, flags
);
389 scsi_device_put(sdev
);
392 spin_unlock_irqrestore(shost
->host_lock
, flags
);
395 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
397 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
399 if (atomic_read(&sdev
->device_blocked
) > 0)
404 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
406 if (starget
->can_queue
> 0) {
407 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
409 if (atomic_read(&starget
->target_blocked
) > 0)
415 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
417 if (shost
->can_queue
> 0 &&
418 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
420 if (atomic_read(&shost
->host_blocked
) > 0)
422 if (shost
->host_self_blocked
)
427 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
429 LIST_HEAD(starved_list
);
430 struct scsi_device
*sdev
;
433 spin_lock_irqsave(shost
->host_lock
, flags
);
434 list_splice_init(&shost
->starved_list
, &starved_list
);
436 while (!list_empty(&starved_list
)) {
437 struct request_queue
*slq
;
440 * As long as shost is accepting commands and we have
441 * starved queues, call blk_run_queue. scsi_request_fn
442 * drops the queue_lock and can add us back to the
445 * host_lock protects the starved_list and starved_entry.
446 * scsi_request_fn must get the host_lock before checking
447 * or modifying starved_list or starved_entry.
449 if (scsi_host_is_busy(shost
))
452 sdev
= list_entry(starved_list
.next
,
453 struct scsi_device
, starved_entry
);
454 list_del_init(&sdev
->starved_entry
);
455 if (scsi_target_is_busy(scsi_target(sdev
))) {
456 list_move_tail(&sdev
->starved_entry
,
457 &shost
->starved_list
);
462 * Once we drop the host lock, a racing scsi_remove_device()
463 * call may remove the sdev from the starved list and destroy
464 * it and the queue. Mitigate by taking a reference to the
465 * queue and never touching the sdev again after we drop the
466 * host lock. Note: if __scsi_remove_device() invokes
467 * blk_cleanup_queue() before the queue is run from this
468 * function then blk_run_queue() will return immediately since
469 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
471 slq
= sdev
->request_queue
;
472 if (!blk_get_queue(slq
))
474 spin_unlock_irqrestore(shost
->host_lock
, flags
);
476 scsi_kick_queue(slq
);
479 spin_lock_irqsave(shost
->host_lock
, flags
);
481 /* put any unprocessed entries back */
482 list_splice(&starved_list
, &shost
->starved_list
);
483 spin_unlock_irqrestore(shost
->host_lock
, flags
);
487 * Function: scsi_run_queue()
489 * Purpose: Select a proper request queue to serve next
491 * Arguments: q - last request's queue
495 * Notes: The previous command was completely finished, start
496 * a new one if possible.
498 static void scsi_run_queue(struct request_queue
*q
)
500 struct scsi_device
*sdev
= q
->queuedata
;
502 if (scsi_target(sdev
)->single_lun
)
503 scsi_single_lun_run(sdev
);
504 if (!list_empty(&sdev
->host
->starved_list
))
505 scsi_starved_list_run(sdev
->host
);
508 blk_mq_run_hw_queues(q
, false);
513 void scsi_requeue_run_queue(struct work_struct
*work
)
515 struct scsi_device
*sdev
;
516 struct request_queue
*q
;
518 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
519 q
= sdev
->request_queue
;
524 * Function: scsi_requeue_command()
526 * Purpose: Handle post-processing of completed commands.
528 * Arguments: q - queue to operate on
529 * cmd - command that may need to be requeued.
533 * Notes: After command completion, there may be blocks left
534 * over which weren't finished by the previous command
535 * this can be for a number of reasons - the main one is
536 * I/O errors in the middle of the request, in which case
537 * we need to request the blocks that come after the bad
539 * Notes: Upon return, cmd is a stale pointer.
541 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
543 struct scsi_device
*sdev
= cmd
->device
;
544 struct request
*req
= cmd
->request
;
547 spin_lock_irqsave(q
->queue_lock
, flags
);
548 blk_unprep_request(req
);
550 scsi_put_command(cmd
);
551 blk_requeue_request(q
, req
);
552 spin_unlock_irqrestore(q
->queue_lock
, flags
);
556 put_device(&sdev
->sdev_gendev
);
559 void scsi_run_host_queues(struct Scsi_Host
*shost
)
561 struct scsi_device
*sdev
;
563 shost_for_each_device(sdev
, shost
)
564 scsi_run_queue(sdev
->request_queue
);
567 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
569 if (!blk_rq_is_passthrough(cmd
->request
)) {
570 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
572 if (drv
->uninit_command
)
573 drv
->uninit_command(cmd
);
577 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
579 struct scsi_data_buffer
*sdb
;
581 if (cmd
->sdb
.table
.nents
)
582 sg_free_table_chained(&cmd
->sdb
.table
, true);
583 if (cmd
->request
->next_rq
) {
584 sdb
= cmd
->request
->next_rq
->special
;
586 sg_free_table_chained(&sdb
->table
, true);
588 if (scsi_prot_sg_count(cmd
))
589 sg_free_table_chained(&cmd
->prot_sdb
->table
, true);
592 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
594 scsi_mq_free_sgtables(cmd
);
595 scsi_uninit_cmd(cmd
);
596 scsi_del_cmd_from_list(cmd
);
600 * Function: scsi_release_buffers()
602 * Purpose: Free resources allocate for a scsi_command.
604 * Arguments: cmd - command that we are bailing.
606 * Lock status: Assumed that no lock is held upon entry.
610 * Notes: In the event that an upper level driver rejects a
611 * command, we must release resources allocated during
612 * the __init_io() function. Primarily this would involve
613 * the scatter-gather table.
615 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
617 if (cmd
->sdb
.table
.nents
)
618 sg_free_table_chained(&cmd
->sdb
.table
, false);
620 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
622 if (scsi_prot_sg_count(cmd
))
623 sg_free_table_chained(&cmd
->prot_sdb
->table
, false);
626 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
628 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
630 sg_free_table_chained(&bidi_sdb
->table
, false);
631 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
632 cmd
->request
->next_rq
->special
= NULL
;
635 static bool scsi_end_request(struct request
*req
, blk_status_t error
,
636 unsigned int bytes
, unsigned int bidi_bytes
)
638 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
639 struct scsi_device
*sdev
= cmd
->device
;
640 struct request_queue
*q
= sdev
->request_queue
;
642 if (blk_update_request(req
, error
, bytes
))
645 /* Bidi request must be completed as a whole */
646 if (unlikely(bidi_bytes
) &&
647 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
650 if (blk_queue_add_random(q
))
651 add_disk_randomness(req
->rq_disk
);
653 if (!blk_rq_is_scsi(req
)) {
654 WARN_ON_ONCE(!(cmd
->flags
& SCMD_INITIALIZED
));
655 cmd
->flags
&= ~SCMD_INITIALIZED
;
660 * In the MQ case the command gets freed by __blk_mq_end_request,
661 * so we have to do all cleanup that depends on it earlier.
663 * We also can't kick the queues from irq context, so we
664 * will have to defer it to a workqueue.
666 scsi_mq_uninit_cmd(cmd
);
668 __blk_mq_end_request(req
, error
);
670 if (scsi_target(sdev
)->single_lun
||
671 !list_empty(&sdev
->host
->starved_list
))
672 kblockd_schedule_work(&sdev
->requeue_work
);
674 blk_mq_run_hw_queues(q
, true);
679 scsi_release_bidi_buffers(cmd
);
680 scsi_release_buffers(cmd
);
681 scsi_put_command(cmd
);
683 spin_lock_irqsave(q
->queue_lock
, flags
);
684 blk_finish_request(req
, error
);
685 spin_unlock_irqrestore(q
->queue_lock
, flags
);
690 put_device(&sdev
->sdev_gendev
);
695 * __scsi_error_from_host_byte - translate SCSI error code into errno
696 * @cmd: SCSI command (unused)
697 * @result: scsi error code
699 * Translate SCSI error code into block errors.
701 static blk_status_t
__scsi_error_from_host_byte(struct scsi_cmnd
*cmd
,
704 switch (host_byte(result
)) {
705 case DID_TRANSPORT_FAILFAST
:
706 return BLK_STS_TRANSPORT
;
707 case DID_TARGET_FAILURE
:
708 set_host_byte(cmd
, DID_OK
);
709 return BLK_STS_TARGET
;
710 case DID_NEXUS_FAILURE
:
711 return BLK_STS_NEXUS
;
712 case DID_ALLOC_FAILURE
:
713 set_host_byte(cmd
, DID_OK
);
714 return BLK_STS_NOSPC
;
715 case DID_MEDIUM_ERROR
:
716 set_host_byte(cmd
, DID_OK
);
717 return BLK_STS_MEDIUM
;
719 return BLK_STS_IOERR
;
724 * Function: scsi_io_completion()
726 * Purpose: Completion processing for block device I/O requests.
728 * Arguments: cmd - command that is finished.
730 * Lock status: Assumed that no lock is held upon entry.
734 * Notes: We will finish off the specified number of sectors. If we
735 * are done, the command block will be released and the queue
736 * function will be goosed. If we are not done then we have to
737 * figure out what to do next:
739 * a) We can call scsi_requeue_command(). The request
740 * will be unprepared and put back on the queue. Then
741 * a new command will be created for it. This should
742 * be used if we made forward progress, or if we want
743 * to switch from READ(10) to READ(6) for example.
745 * b) We can call __scsi_queue_insert(). The request will
746 * be put back on the queue and retried using the same
747 * command as before, possibly after a delay.
749 * c) We can call scsi_end_request() with -EIO to fail
750 * the remainder of the request.
752 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
754 int result
= cmd
->result
;
755 struct request_queue
*q
= cmd
->device
->request_queue
;
756 struct request
*req
= cmd
->request
;
757 blk_status_t error
= BLK_STS_OK
;
758 struct scsi_sense_hdr sshdr
;
759 bool sense_valid
= false;
760 int sense_deferred
= 0, level
= 0;
761 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
762 ACTION_DELAYED_RETRY
} action
;
763 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
766 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
768 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
771 if (blk_rq_is_passthrough(req
)) {
775 * SG_IO wants current and deferred errors
777 scsi_req(req
)->sense_len
=
778 min(8 + cmd
->sense_buffer
[7],
779 SCSI_SENSE_BUFFERSIZE
);
782 error
= __scsi_error_from_host_byte(cmd
, result
);
785 * __scsi_error_from_host_byte may have reset the host_byte
787 scsi_req(req
)->result
= cmd
->result
;
788 scsi_req(req
)->resid_len
= scsi_get_resid(cmd
);
790 if (scsi_bidi_cmnd(cmd
)) {
792 * Bidi commands Must be complete as a whole,
793 * both sides at once.
795 scsi_req(req
->next_rq
)->resid_len
= scsi_in(cmd
)->resid
;
796 if (scsi_end_request(req
, BLK_STS_OK
, blk_rq_bytes(req
),
797 blk_rq_bytes(req
->next_rq
)))
801 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
803 * Flush commands do not transfers any data, and thus cannot use
804 * good_bytes != blk_rq_bytes(req) as the signal for an error.
805 * This sets the error explicitly for the problem case.
807 error
= __scsi_error_from_host_byte(cmd
, result
);
810 /* no bidi support for !blk_rq_is_passthrough yet */
811 BUG_ON(blk_bidi_rq(req
));
814 * Next deal with any sectors which we were able to correctly
817 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO
, cmd
,
818 "%u sectors total, %d bytes done.\n",
819 blk_rq_sectors(req
), good_bytes
));
822 * Recovered errors need reporting, but they're always treated as
823 * success, so fiddle the result code here. For passthrough requests
824 * we already took a copy of the original into sreq->result which
825 * is what gets returned to the user
827 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
828 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
829 * print since caller wants ATA registers. Only occurs on
830 * SCSI ATA PASS_THROUGH commands when CK_COND=1
832 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
834 else if (!(req
->rq_flags
& RQF_QUIET
))
835 scsi_print_sense(cmd
);
837 /* for passthrough error may be set */
842 * special case: failed zero length commands always need to
843 * drop down into the retry code. Otherwise, if we finished
844 * all bytes in the request we are done now.
846 if (!(blk_rq_bytes(req
) == 0 && error
) &&
847 !scsi_end_request(req
, error
, good_bytes
, 0))
851 * Kill remainder if no retrys.
853 if (error
&& scsi_noretry_cmd(cmd
)) {
854 if (scsi_end_request(req
, error
, blk_rq_bytes(req
), 0))
860 * If there had been no error, but we have leftover bytes in the
861 * requeues just queue the command up again.
866 error
= __scsi_error_from_host_byte(cmd
, result
);
868 if (host_byte(result
) == DID_RESET
) {
869 /* Third party bus reset or reset for error recovery
870 * reasons. Just retry the command and see what
873 action
= ACTION_RETRY
;
874 } else if (sense_valid
&& !sense_deferred
) {
875 switch (sshdr
.sense_key
) {
877 if (cmd
->device
->removable
) {
878 /* Detected disc change. Set a bit
879 * and quietly refuse further access.
881 cmd
->device
->changed
= 1;
882 action
= ACTION_FAIL
;
884 /* Must have been a power glitch, or a
885 * bus reset. Could not have been a
886 * media change, so we just retry the
887 * command and see what happens.
889 action
= ACTION_RETRY
;
892 case ILLEGAL_REQUEST
:
893 /* If we had an ILLEGAL REQUEST returned, then
894 * we may have performed an unsupported
895 * command. The only thing this should be
896 * would be a ten byte read where only a six
897 * byte read was supported. Also, on a system
898 * where READ CAPACITY failed, we may have
899 * read past the end of the disk.
901 if ((cmd
->device
->use_10_for_rw
&&
902 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
903 (cmd
->cmnd
[0] == READ_10
||
904 cmd
->cmnd
[0] == WRITE_10
)) {
905 /* This will issue a new 6-byte command. */
906 cmd
->device
->use_10_for_rw
= 0;
907 action
= ACTION_REPREP
;
908 } else if (sshdr
.asc
== 0x10) /* DIX */ {
909 action
= ACTION_FAIL
;
910 error
= BLK_STS_PROTECTION
;
911 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
912 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
913 action
= ACTION_FAIL
;
914 error
= BLK_STS_TARGET
;
916 action
= ACTION_FAIL
;
918 case ABORTED_COMMAND
:
919 action
= ACTION_FAIL
;
920 if (sshdr
.asc
== 0x10) /* DIF */
921 error
= BLK_STS_PROTECTION
;
924 /* If the device is in the process of becoming
925 * ready, or has a temporary blockage, retry.
927 if (sshdr
.asc
== 0x04) {
928 switch (sshdr
.ascq
) {
929 case 0x01: /* becoming ready */
930 case 0x04: /* format in progress */
931 case 0x05: /* rebuild in progress */
932 case 0x06: /* recalculation in progress */
933 case 0x07: /* operation in progress */
934 case 0x08: /* Long write in progress */
935 case 0x09: /* self test in progress */
936 case 0x14: /* space allocation in progress */
937 action
= ACTION_DELAYED_RETRY
;
940 action
= ACTION_FAIL
;
944 action
= ACTION_FAIL
;
946 case VOLUME_OVERFLOW
:
947 /* See SSC3rXX or current. */
948 action
= ACTION_FAIL
;
951 action
= ACTION_FAIL
;
955 action
= ACTION_FAIL
;
957 if (action
!= ACTION_FAIL
&&
958 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
))
959 action
= ACTION_FAIL
;
963 /* Give up and fail the remainder of the request */
964 if (!(req
->rq_flags
& RQF_QUIET
)) {
965 static DEFINE_RATELIMIT_STATE(_rs
,
966 DEFAULT_RATELIMIT_INTERVAL
,
967 DEFAULT_RATELIMIT_BURST
);
969 if (unlikely(scsi_logging_level
))
970 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
971 SCSI_LOG_MLCOMPLETE_BITS
);
974 * if logging is enabled the failure will be printed
975 * in scsi_log_completion(), so avoid duplicate messages
977 if (!level
&& __ratelimit(&_rs
)) {
978 scsi_print_result(cmd
, NULL
, FAILED
);
979 if (driver_byte(result
) & DRIVER_SENSE
)
980 scsi_print_sense(cmd
);
981 scsi_print_command(cmd
);
984 if (!scsi_end_request(req
, error
, blk_rq_err_bytes(req
), 0))
989 /* Unprep the request and put it back at the head of the queue.
990 * A new command will be prepared and issued.
993 scsi_mq_requeue_cmd(cmd
);
995 scsi_release_buffers(cmd
);
996 scsi_requeue_command(q
, cmd
);
1000 /* Retry the same command immediately */
1001 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1003 case ACTION_DELAYED_RETRY
:
1004 /* Retry the same command after a delay */
1005 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1010 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
)
1015 * If sg table allocation fails, requeue request later.
1017 if (unlikely(sg_alloc_table_chained(&sdb
->table
,
1018 blk_rq_nr_phys_segments(req
), sdb
->table
.sgl
)))
1019 return BLKPREP_DEFER
;
1022 * Next, walk the list, and fill in the addresses and sizes of
1025 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1026 BUG_ON(count
> sdb
->table
.nents
);
1027 sdb
->table
.nents
= count
;
1028 sdb
->length
= blk_rq_payload_bytes(req
);
1033 * Function: scsi_init_io()
1035 * Purpose: SCSI I/O initialize function.
1037 * Arguments: cmd - Command descriptor we wish to initialize
1039 * Returns: 0 on success
1040 * BLKPREP_DEFER if the failure is retryable
1041 * BLKPREP_KILL if the failure is fatal
1043 int scsi_init_io(struct scsi_cmnd
*cmd
)
1045 struct scsi_device
*sdev
= cmd
->device
;
1046 struct request
*rq
= cmd
->request
;
1047 bool is_mq
= (rq
->mq_ctx
!= NULL
);
1048 int error
= BLKPREP_KILL
;
1050 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq
)))
1053 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1057 if (blk_bidi_rq(rq
)) {
1058 if (!rq
->q
->mq_ops
) {
1059 struct scsi_data_buffer
*bidi_sdb
=
1060 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1062 error
= BLKPREP_DEFER
;
1066 rq
->next_rq
->special
= bidi_sdb
;
1069 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1074 if (blk_integrity_rq(rq
)) {
1075 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1078 if (prot_sdb
== NULL
) {
1080 * This can happen if someone (e.g. multipath)
1081 * queues a command to a device on an adapter
1082 * that does not support DIX.
1085 error
= BLKPREP_KILL
;
1089 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1091 if (sg_alloc_table_chained(&prot_sdb
->table
, ivecs
,
1092 prot_sdb
->table
.sgl
)) {
1093 error
= BLKPREP_DEFER
;
1097 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1098 prot_sdb
->table
.sgl
);
1099 BUG_ON(unlikely(count
> ivecs
));
1100 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1102 cmd
->prot_sdb
= prot_sdb
;
1103 cmd
->prot_sdb
->table
.nents
= count
;
1109 scsi_mq_free_sgtables(cmd
);
1111 scsi_release_buffers(cmd
);
1112 cmd
->request
->special
= NULL
;
1113 scsi_put_command(cmd
);
1114 put_device(&sdev
->sdev_gendev
);
1118 EXPORT_SYMBOL(scsi_init_io
);
1121 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1122 * @rq: Request associated with the SCSI command to be initialized.
1124 * This function initializes the members of struct scsi_cmnd that must be
1125 * initialized before request processing starts and that won't be
1126 * reinitialized if a SCSI command is requeued.
1128 * Called from inside blk_get_request() for pass-through requests and from
1129 * inside scsi_init_command() for filesystem requests.
1131 void scsi_initialize_rq(struct request
*rq
)
1133 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
1135 scsi_req_init(&cmd
->req
);
1136 cmd
->jiffies_at_alloc
= jiffies
;
1139 EXPORT_SYMBOL(scsi_initialize_rq
);
1141 /* Add a command to the list used by the aacraid and dpt_i2o drivers */
1142 void scsi_add_cmd_to_list(struct scsi_cmnd
*cmd
)
1144 struct scsi_device
*sdev
= cmd
->device
;
1145 struct Scsi_Host
*shost
= sdev
->host
;
1146 unsigned long flags
;
1148 if (shost
->use_cmd_list
) {
1149 spin_lock_irqsave(&sdev
->list_lock
, flags
);
1150 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1151 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
1155 /* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1156 void scsi_del_cmd_from_list(struct scsi_cmnd
*cmd
)
1158 struct scsi_device
*sdev
= cmd
->device
;
1159 struct Scsi_Host
*shost
= sdev
->host
;
1160 unsigned long flags
;
1162 if (shost
->use_cmd_list
) {
1163 spin_lock_irqsave(&sdev
->list_lock
, flags
);
1164 BUG_ON(list_empty(&cmd
->list
));
1165 list_del_init(&cmd
->list
);
1166 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
1170 /* Called after a request has been started. */
1171 void scsi_init_command(struct scsi_device
*dev
, struct scsi_cmnd
*cmd
)
1173 void *buf
= cmd
->sense_buffer
;
1174 void *prot
= cmd
->prot_sdb
;
1175 struct request
*rq
= blk_mq_rq_from_pdu(cmd
);
1176 unsigned int flags
= cmd
->flags
& SCMD_PRESERVED_FLAGS
;
1177 unsigned long jiffies_at_alloc
;
1180 if (!blk_rq_is_scsi(rq
) && !(flags
& SCMD_INITIALIZED
)) {
1181 flags
|= SCMD_INITIALIZED
;
1182 scsi_initialize_rq(rq
);
1185 jiffies_at_alloc
= cmd
->jiffies_at_alloc
;
1186 retries
= cmd
->retries
;
1187 /* zero out the cmd, except for the embedded scsi_request */
1188 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1189 sizeof(*cmd
) - sizeof(cmd
->req
) + dev
->host
->hostt
->cmd_size
);
1192 cmd
->sense_buffer
= buf
;
1193 cmd
->prot_sdb
= prot
;
1195 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1196 cmd
->jiffies_at_alloc
= jiffies_at_alloc
;
1197 cmd
->retries
= retries
;
1199 scsi_add_cmd_to_list(cmd
);
1202 static int scsi_setup_scsi_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1204 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1207 * Passthrough requests may transfer data, in which case they must
1208 * a bio attached to them. Or they might contain a SCSI command
1209 * that does not transfer data, in which case they may optionally
1210 * submit a request without an attached bio.
1213 int ret
= scsi_init_io(cmd
);
1217 BUG_ON(blk_rq_bytes(req
));
1219 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1222 cmd
->cmd_len
= scsi_req(req
)->cmd_len
;
1223 cmd
->cmnd
= scsi_req(req
)->cmd
;
1224 cmd
->transfersize
= blk_rq_bytes(req
);
1225 cmd
->allowed
= scsi_req(req
)->retries
;
1230 * Setup a normal block command. These are simple request from filesystems
1231 * that still need to be translated to SCSI CDBs from the ULD.
1233 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1235 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1237 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1238 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1239 if (ret
!= BLKPREP_OK
)
1243 cmd
->cmnd
= scsi_req(req
)->cmd
= scsi_req(req
)->__cmd
;
1244 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1245 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1248 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1250 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1252 if (!blk_rq_bytes(req
))
1253 cmd
->sc_data_direction
= DMA_NONE
;
1254 else if (rq_data_dir(req
) == WRITE
)
1255 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1257 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1259 if (blk_rq_is_scsi(req
))
1260 return scsi_setup_scsi_cmnd(sdev
, req
);
1262 return scsi_setup_fs_cmnd(sdev
, req
);
1266 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1268 int ret
= BLKPREP_OK
;
1271 * If the device is not in running state we will reject some
1274 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1275 switch (sdev
->sdev_state
) {
1277 case SDEV_TRANSPORT_OFFLINE
:
1279 * If the device is offline we refuse to process any
1280 * commands. The device must be brought online
1281 * before trying any recovery commands.
1283 sdev_printk(KERN_ERR
, sdev
,
1284 "rejecting I/O to offline device\n");
1289 * If the device is fully deleted, we refuse to
1290 * process any commands as well.
1292 sdev_printk(KERN_ERR
, sdev
,
1293 "rejecting I/O to dead device\n");
1297 case SDEV_CREATED_BLOCK
:
1298 ret
= BLKPREP_DEFER
;
1302 * If the devices is blocked we defer normal commands.
1304 if (!(req
->rq_flags
& RQF_PREEMPT
))
1305 ret
= BLKPREP_DEFER
;
1309 * For any other not fully online state we only allow
1310 * special commands. In particular any user initiated
1311 * command is not allowed.
1313 if (!(req
->rq_flags
& RQF_PREEMPT
))
1322 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1324 struct scsi_device
*sdev
= q
->queuedata
;
1328 case BLKPREP_INVALID
:
1329 scsi_req(req
)->result
= DID_NO_CONNECT
<< 16;
1330 /* release the command and kill it */
1332 struct scsi_cmnd
*cmd
= req
->special
;
1333 scsi_release_buffers(cmd
);
1334 scsi_put_command(cmd
);
1335 put_device(&sdev
->sdev_gendev
);
1336 req
->special
= NULL
;
1341 * If we defer, the blk_peek_request() returns NULL, but the
1342 * queue must be restarted, so we schedule a callback to happen
1345 if (atomic_read(&sdev
->device_busy
) == 0)
1346 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1349 req
->rq_flags
|= RQF_DONTPREP
;
1355 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1357 struct scsi_device
*sdev
= q
->queuedata
;
1358 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1361 ret
= scsi_prep_state_check(sdev
, req
);
1362 if (ret
!= BLKPREP_OK
)
1365 if (!req
->special
) {
1366 /* Bail if we can't get a reference to the device */
1367 if (unlikely(!get_device(&sdev
->sdev_gendev
))) {
1368 ret
= BLKPREP_DEFER
;
1372 scsi_init_command(sdev
, cmd
);
1376 cmd
->tag
= req
->tag
;
1378 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1380 ret
= scsi_setup_cmnd(sdev
, req
);
1382 return scsi_prep_return(q
, req
, ret
);
1385 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1387 scsi_uninit_cmd(blk_mq_rq_to_pdu(req
));
1391 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1394 * Called with the queue_lock held.
1396 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1397 struct scsi_device
*sdev
)
1401 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1402 if (atomic_read(&sdev
->device_blocked
)) {
1407 * unblock after device_blocked iterates to zero
1409 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1411 * For the MQ case we take care of this in the caller.
1414 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1417 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1418 "unblocking device at zero depth\n"));
1421 if (busy
>= sdev
->queue_depth
)
1426 atomic_dec(&sdev
->device_busy
);
1431 * scsi_target_queue_ready: checks if there we can send commands to target
1432 * @sdev: scsi device on starget to check.
1434 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1435 struct scsi_device
*sdev
)
1437 struct scsi_target
*starget
= scsi_target(sdev
);
1440 if (starget
->single_lun
) {
1441 spin_lock_irq(shost
->host_lock
);
1442 if (starget
->starget_sdev_user
&&
1443 starget
->starget_sdev_user
!= sdev
) {
1444 spin_unlock_irq(shost
->host_lock
);
1447 starget
->starget_sdev_user
= sdev
;
1448 spin_unlock_irq(shost
->host_lock
);
1451 if (starget
->can_queue
<= 0)
1454 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1455 if (atomic_read(&starget
->target_blocked
) > 0) {
1460 * unblock after target_blocked iterates to zero
1462 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1465 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1466 "unblocking target at zero depth\n"));
1469 if (busy
>= starget
->can_queue
)
1475 spin_lock_irq(shost
->host_lock
);
1476 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1477 spin_unlock_irq(shost
->host_lock
);
1479 if (starget
->can_queue
> 0)
1480 atomic_dec(&starget
->target_busy
);
1485 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1486 * return 0. We must end up running the queue again whenever 0 is
1487 * returned, else IO can hang.
1489 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1490 struct Scsi_Host
*shost
,
1491 struct scsi_device
*sdev
)
1495 if (scsi_host_in_recovery(shost
))
1498 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1499 if (atomic_read(&shost
->host_blocked
) > 0) {
1504 * unblock after host_blocked iterates to zero
1506 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1510 shost_printk(KERN_INFO
, shost
,
1511 "unblocking host at zero depth\n"));
1514 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1516 if (shost
->host_self_blocked
)
1519 /* We're OK to process the command, so we can't be starved */
1520 if (!list_empty(&sdev
->starved_entry
)) {
1521 spin_lock_irq(shost
->host_lock
);
1522 if (!list_empty(&sdev
->starved_entry
))
1523 list_del_init(&sdev
->starved_entry
);
1524 spin_unlock_irq(shost
->host_lock
);
1530 spin_lock_irq(shost
->host_lock
);
1531 if (list_empty(&sdev
->starved_entry
))
1532 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1533 spin_unlock_irq(shost
->host_lock
);
1535 atomic_dec(&shost
->host_busy
);
1540 * Busy state exporting function for request stacking drivers.
1542 * For efficiency, no lock is taken to check the busy state of
1543 * shost/starget/sdev, since the returned value is not guaranteed and
1544 * may be changed after request stacking drivers call the function,
1545 * regardless of taking lock or not.
1547 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1548 * needs to return 'not busy'. Otherwise, request stacking drivers
1549 * may hold requests forever.
1551 static int scsi_lld_busy(struct request_queue
*q
)
1553 struct scsi_device
*sdev
= q
->queuedata
;
1554 struct Scsi_Host
*shost
;
1556 if (blk_queue_dying(q
))
1562 * Ignore host/starget busy state.
1563 * Since block layer does not have a concept of fairness across
1564 * multiple queues, congestion of host/starget needs to be handled
1567 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1574 * Kill a request for a dead device
1576 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1578 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1579 struct scsi_device
*sdev
;
1580 struct scsi_target
*starget
;
1581 struct Scsi_Host
*shost
;
1583 blk_start_request(req
);
1585 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1588 starget
= scsi_target(sdev
);
1590 scsi_init_cmd_errh(cmd
);
1591 cmd
->result
= DID_NO_CONNECT
<< 16;
1592 atomic_inc(&cmd
->device
->iorequest_cnt
);
1595 * SCSI request completion path will do scsi_device_unbusy(),
1596 * bump busy counts. To bump the counters, we need to dance
1597 * with the locks as normal issue path does.
1599 atomic_inc(&sdev
->device_busy
);
1600 atomic_inc(&shost
->host_busy
);
1601 if (starget
->can_queue
> 0)
1602 atomic_inc(&starget
->target_busy
);
1604 blk_complete_request(req
);
1607 static void scsi_softirq_done(struct request
*rq
)
1609 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
1610 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1613 INIT_LIST_HEAD(&cmd
->eh_entry
);
1615 atomic_inc(&cmd
->device
->iodone_cnt
);
1617 atomic_inc(&cmd
->device
->ioerr_cnt
);
1619 disposition
= scsi_decide_disposition(cmd
);
1620 if (disposition
!= SUCCESS
&&
1621 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1622 sdev_printk(KERN_ERR
, cmd
->device
,
1623 "timing out command, waited %lus\n",
1625 disposition
= SUCCESS
;
1628 scsi_log_completion(cmd
, disposition
);
1630 switch (disposition
) {
1632 scsi_finish_command(cmd
);
1635 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1637 case ADD_TO_MLQUEUE
:
1638 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1641 scsi_eh_scmd_add(cmd
);
1647 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1648 * @cmd: command block we are dispatching.
1650 * Return: nonzero return request was rejected and device's queue needs to be
1653 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1655 struct Scsi_Host
*host
= cmd
->device
->host
;
1658 atomic_inc(&cmd
->device
->iorequest_cnt
);
1660 /* check if the device is still usable */
1661 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1662 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1663 * returns an immediate error upwards, and signals
1664 * that the device is no longer present */
1665 cmd
->result
= DID_NO_CONNECT
<< 16;
1669 /* Check to see if the scsi lld made this device blocked. */
1670 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1672 * in blocked state, the command is just put back on
1673 * the device queue. The suspend state has already
1674 * blocked the queue so future requests should not
1675 * occur until the device transitions out of the
1678 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1679 "queuecommand : device blocked\n"));
1680 return SCSI_MLQUEUE_DEVICE_BUSY
;
1683 /* Store the LUN value in cmnd, if needed. */
1684 if (cmd
->device
->lun_in_cdb
)
1685 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1686 (cmd
->device
->lun
<< 5 & 0xe0);
1691 * Before we queue this command, check if the command
1692 * length exceeds what the host adapter can handle.
1694 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1695 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1696 "queuecommand : command too long. "
1697 "cdb_size=%d host->max_cmd_len=%d\n",
1698 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1699 cmd
->result
= (DID_ABORT
<< 16);
1703 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1704 cmd
->result
= (DID_NO_CONNECT
<< 16);
1709 trace_scsi_dispatch_cmd_start(cmd
);
1710 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1712 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1713 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1714 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1715 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1717 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1718 "queuecommand : request rejected\n"));
1723 cmd
->scsi_done(cmd
);
1728 * scsi_done - Invoke completion on finished SCSI command.
1729 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1730 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1732 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1733 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1734 * calls blk_complete_request() for further processing.
1736 * This function is interrupt context safe.
1738 static void scsi_done(struct scsi_cmnd
*cmd
)
1740 trace_scsi_dispatch_cmd_done(cmd
);
1741 blk_complete_request(cmd
->request
);
1745 * Function: scsi_request_fn()
1747 * Purpose: Main strategy routine for SCSI.
1749 * Arguments: q - Pointer to actual queue.
1753 * Lock status: IO request lock assumed to be held when called.
1755 static void scsi_request_fn(struct request_queue
*q
)
1756 __releases(q
->queue_lock
)
1757 __acquires(q
->queue_lock
)
1759 struct scsi_device
*sdev
= q
->queuedata
;
1760 struct Scsi_Host
*shost
;
1761 struct scsi_cmnd
*cmd
;
1762 struct request
*req
;
1765 * To start with, we keep looping until the queue is empty, or until
1766 * the host is no longer able to accept any more requests.
1772 * get next queueable request. We do this early to make sure
1773 * that the request is fully prepared even if we cannot
1776 req
= blk_peek_request(q
);
1780 if (unlikely(!scsi_device_online(sdev
))) {
1781 sdev_printk(KERN_ERR
, sdev
,
1782 "rejecting I/O to offline device\n");
1783 scsi_kill_request(req
, q
);
1787 if (!scsi_dev_queue_ready(q
, sdev
))
1791 * Remove the request from the request list.
1793 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1794 blk_start_request(req
);
1796 spin_unlock_irq(q
->queue_lock
);
1797 cmd
= blk_mq_rq_to_pdu(req
);
1798 if (cmd
!= req
->special
) {
1799 printk(KERN_CRIT
"impossible request in %s.\n"
1800 "please mail a stack trace to "
1801 "linux-scsi@vger.kernel.org\n",
1803 blk_dump_rq_flags(req
, "foo");
1808 * We hit this when the driver is using a host wide
1809 * tag map. For device level tag maps the queue_depth check
1810 * in the device ready fn would prevent us from trying
1811 * to allocate a tag. Since the map is a shared host resource
1812 * we add the dev to the starved list so it eventually gets
1813 * a run when a tag is freed.
1815 if (blk_queue_tagged(q
) && !(req
->rq_flags
& RQF_QUEUED
)) {
1816 spin_lock_irq(shost
->host_lock
);
1817 if (list_empty(&sdev
->starved_entry
))
1818 list_add_tail(&sdev
->starved_entry
,
1819 &shost
->starved_list
);
1820 spin_unlock_irq(shost
->host_lock
);
1824 if (!scsi_target_queue_ready(shost
, sdev
))
1827 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1828 goto host_not_ready
;
1830 if (sdev
->simple_tags
)
1831 cmd
->flags
|= SCMD_TAGGED
;
1833 cmd
->flags
&= ~SCMD_TAGGED
;
1836 * Finally, initialize any error handling parameters, and set up
1837 * the timers for timeouts.
1839 scsi_init_cmd_errh(cmd
);
1842 * Dispatch the command to the low-level driver.
1844 cmd
->scsi_done
= scsi_done
;
1845 rtn
= scsi_dispatch_cmd(cmd
);
1847 scsi_queue_insert(cmd
, rtn
);
1848 spin_lock_irq(q
->queue_lock
);
1851 spin_lock_irq(q
->queue_lock
);
1857 if (scsi_target(sdev
)->can_queue
> 0)
1858 atomic_dec(&scsi_target(sdev
)->target_busy
);
1861 * lock q, handle tag, requeue req, and decrement device_busy. We
1862 * must return with queue_lock held.
1864 * Decrementing device_busy without checking it is OK, as all such
1865 * cases (host limits or settings) should run the queue at some
1868 spin_lock_irq(q
->queue_lock
);
1869 blk_requeue_request(q
, req
);
1870 atomic_dec(&sdev
->device_busy
);
1872 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1873 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1876 static inline blk_status_t
prep_to_mq(int ret
)
1882 return BLK_STS_RESOURCE
;
1884 return BLK_STS_IOERR
;
1888 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1889 static unsigned int scsi_mq_sgl_size(struct Scsi_Host
*shost
)
1891 return min_t(unsigned int, shost
->sg_tablesize
, SG_CHUNK_SIZE
) *
1892 sizeof(struct scatterlist
);
1895 static int scsi_mq_prep_fn(struct request
*req
)
1897 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1898 struct scsi_device
*sdev
= req
->q
->queuedata
;
1899 struct Scsi_Host
*shost
= sdev
->host
;
1900 struct scatterlist
*sg
;
1902 scsi_init_command(sdev
, cmd
);
1908 cmd
->tag
= req
->tag
;
1909 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1911 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1912 cmd
->sdb
.table
.sgl
= sg
;
1914 if (scsi_host_get_prot(shost
)) {
1915 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1917 cmd
->prot_sdb
->table
.sgl
=
1918 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1921 if (blk_bidi_rq(req
)) {
1922 struct request
*next_rq
= req
->next_rq
;
1923 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1925 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1926 bidi_sdb
->table
.sgl
=
1927 (struct scatterlist
*)(bidi_sdb
+ 1);
1929 next_rq
->special
= bidi_sdb
;
1932 blk_mq_start_request(req
);
1934 return scsi_setup_cmnd(sdev
, req
);
1937 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1939 trace_scsi_dispatch_cmd_done(cmd
);
1940 blk_mq_complete_request(cmd
->request
);
1943 static blk_status_t
scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1944 const struct blk_mq_queue_data
*bd
)
1946 struct request
*req
= bd
->rq
;
1947 struct request_queue
*q
= req
->q
;
1948 struct scsi_device
*sdev
= q
->queuedata
;
1949 struct Scsi_Host
*shost
= sdev
->host
;
1950 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1954 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1955 if (ret
!= BLK_STS_OK
)
1958 ret
= BLK_STS_RESOURCE
;
1959 if (!get_device(&sdev
->sdev_gendev
))
1962 if (!scsi_dev_queue_ready(q
, sdev
))
1963 goto out_put_device
;
1964 if (!scsi_target_queue_ready(shost
, sdev
))
1965 goto out_dec_device_busy
;
1966 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1967 goto out_dec_target_busy
;
1969 if (!(req
->rq_flags
& RQF_DONTPREP
)) {
1970 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1971 if (ret
!= BLK_STS_OK
)
1972 goto out_dec_host_busy
;
1973 req
->rq_flags
|= RQF_DONTPREP
;
1975 blk_mq_start_request(req
);
1978 if (sdev
->simple_tags
)
1979 cmd
->flags
|= SCMD_TAGGED
;
1981 cmd
->flags
&= ~SCMD_TAGGED
;
1983 scsi_init_cmd_errh(cmd
);
1984 cmd
->scsi_done
= scsi_mq_done
;
1986 reason
= scsi_dispatch_cmd(cmd
);
1988 scsi_set_blocked(cmd
, reason
);
1989 ret
= BLK_STS_RESOURCE
;
1990 goto out_dec_host_busy
;
1996 atomic_dec(&shost
->host_busy
);
1997 out_dec_target_busy
:
1998 if (scsi_target(sdev
)->can_queue
> 0)
1999 atomic_dec(&scsi_target(sdev
)->target_busy
);
2000 out_dec_device_busy
:
2001 atomic_dec(&sdev
->device_busy
);
2003 put_device(&sdev
->sdev_gendev
);
2008 case BLK_STS_RESOURCE
:
2009 if (atomic_read(&sdev
->device_busy
) == 0 &&
2010 !scsi_device_blocked(sdev
))
2011 blk_mq_delay_run_hw_queue(hctx
, SCSI_QUEUE_DELAY
);
2015 * Make sure to release all allocated ressources when
2016 * we hit an error, as we will never see this command
2019 if (req
->rq_flags
& RQF_DONTPREP
)
2020 scsi_mq_uninit_cmd(cmd
);
2026 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
2030 return BLK_EH_RESET_TIMER
;
2031 return scsi_times_out(req
);
2034 static int scsi_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2035 unsigned int hctx_idx
, unsigned int numa_node
)
2037 struct Scsi_Host
*shost
= set
->driver_data
;
2038 const bool unchecked_isa_dma
= shost
->unchecked_isa_dma
;
2039 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2040 struct scatterlist
*sg
;
2042 if (unchecked_isa_dma
)
2043 cmd
->flags
|= SCMD_UNCHECKED_ISA_DMA
;
2044 cmd
->sense_buffer
= scsi_alloc_sense_buffer(unchecked_isa_dma
,
2045 GFP_KERNEL
, numa_node
);
2046 if (!cmd
->sense_buffer
)
2048 cmd
->req
.sense
= cmd
->sense_buffer
;
2050 if (scsi_host_get_prot(shost
)) {
2051 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) +
2052 shost
->hostt
->cmd_size
;
2053 cmd
->prot_sdb
= (void *)sg
+ scsi_mq_sgl_size(shost
);
2059 static void scsi_mq_exit_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2060 unsigned int hctx_idx
)
2062 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2064 scsi_free_sense_buffer(cmd
->flags
& SCMD_UNCHECKED_ISA_DMA
,
2068 static int scsi_map_queues(struct blk_mq_tag_set
*set
)
2070 struct Scsi_Host
*shost
= container_of(set
, struct Scsi_Host
, tag_set
);
2072 if (shost
->hostt
->map_queues
)
2073 return shost
->hostt
->map_queues(shost
);
2074 return blk_mq_map_queues(set
);
2077 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2079 struct device
*host_dev
;
2080 u64 bounce_limit
= 0xffffffff;
2082 if (shost
->unchecked_isa_dma
)
2083 return BLK_BOUNCE_ISA
;
2085 * Platforms with virtual-DMA translation
2086 * hardware have no practical limit.
2088 if (!PCI_DMA_BUS_IS_PHYS
)
2089 return BLK_BOUNCE_ANY
;
2091 host_dev
= scsi_get_device(shost
);
2092 if (host_dev
&& host_dev
->dma_mask
)
2093 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2095 return bounce_limit
;
2098 void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2100 struct device
*dev
= shost
->dma_dev
;
2102 queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH
, q
);
2105 * this limit is imposed by hardware restrictions
2107 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
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
);
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
);
2123 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2125 if (!shost
->use_clustering
)
2126 q
->limits
.cluster
= 0;
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.
2133 blk_queue_dma_alignment(q
, 0x03);
2135 EXPORT_SYMBOL_GPL(__scsi_init_queue
);
2137 static int scsi_old_init_rq(struct request_queue
*q
, struct request
*rq
,
2140 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2141 const bool unchecked_isa_dma
= shost
->unchecked_isa_dma
;
2142 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2144 memset(cmd
, 0, sizeof(*cmd
));
2146 if (unchecked_isa_dma
)
2147 cmd
->flags
|= SCMD_UNCHECKED_ISA_DMA
;
2148 cmd
->sense_buffer
= scsi_alloc_sense_buffer(unchecked_isa_dma
, gfp
,
2150 if (!cmd
->sense_buffer
)
2152 cmd
->req
.sense
= cmd
->sense_buffer
;
2154 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
2155 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp
);
2157 goto fail_free_sense
;
2163 scsi_free_sense_buffer(unchecked_isa_dma
, cmd
->sense_buffer
);
2168 static void scsi_old_exit_rq(struct request_queue
*q
, struct request
*rq
)
2170 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2173 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
2174 scsi_free_sense_buffer(cmd
->flags
& SCMD_UNCHECKED_ISA_DMA
,
2178 struct request_queue
*scsi_old_alloc_queue(struct scsi_device
*sdev
)
2180 struct Scsi_Host
*shost
= sdev
->host
;
2181 struct request_queue
*q
;
2183 q
= blk_alloc_queue_node(GFP_KERNEL
, NUMA_NO_NODE
);
2186 q
->cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
2187 q
->rq_alloc_data
= shost
;
2188 q
->request_fn
= scsi_request_fn
;
2189 q
->init_rq_fn
= scsi_old_init_rq
;
2190 q
->exit_rq_fn
= scsi_old_exit_rq
;
2191 q
->initialize_rq_fn
= scsi_initialize_rq
;
2193 if (blk_init_allocated_queue(q
) < 0) {
2194 blk_cleanup_queue(q
);
2198 __scsi_init_queue(shost
, q
);
2199 blk_queue_prep_rq(q
, scsi_prep_fn
);
2200 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2201 blk_queue_softirq_done(q
, scsi_softirq_done
);
2202 blk_queue_rq_timed_out(q
, scsi_times_out
);
2203 blk_queue_lld_busy(q
, scsi_lld_busy
);
2207 static const struct blk_mq_ops scsi_mq_ops
= {
2208 .queue_rq
= scsi_queue_rq
,
2209 .complete
= scsi_softirq_done
,
2210 .timeout
= scsi_timeout
,
2211 #ifdef CONFIG_BLK_DEBUG_FS
2212 .show_rq
= scsi_show_rq
,
2214 .init_request
= scsi_mq_init_request
,
2215 .exit_request
= scsi_mq_exit_request
,
2216 .initialize_rq_fn
= scsi_initialize_rq
,
2217 .map_queues
= scsi_map_queues
,
2220 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2222 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2223 if (IS_ERR(sdev
->request_queue
))
2226 sdev
->request_queue
->queuedata
= sdev
;
2227 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2228 return sdev
->request_queue
;
2231 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2233 unsigned int cmd_size
, sgl_size
;
2235 sgl_size
= scsi_mq_sgl_size(shost
);
2236 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2237 if (scsi_host_get_prot(shost
))
2238 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2240 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2241 shost
->tag_set
.ops
= &scsi_mq_ops
;
2242 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2243 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2244 shost
->tag_set
.cmd_size
= cmd_size
;
2245 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2246 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2247 shost
->tag_set
.flags
|=
2248 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2249 shost
->tag_set
.driver_data
= shost
;
2251 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2254 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2256 blk_mq_free_tag_set(&shost
->tag_set
);
2260 * scsi_device_from_queue - return sdev associated with a request_queue
2261 * @q: The request queue to return the sdev from
2263 * Return the sdev associated with a request queue or NULL if the
2264 * request_queue does not reference a SCSI device.
2266 struct scsi_device
*scsi_device_from_queue(struct request_queue
*q
)
2268 struct scsi_device
*sdev
= NULL
;
2271 if (q
->mq_ops
== &scsi_mq_ops
)
2272 sdev
= q
->queuedata
;
2273 } else if (q
->request_fn
== scsi_request_fn
)
2274 sdev
= q
->queuedata
;
2275 if (!sdev
|| !get_device(&sdev
->sdev_gendev
))
2280 EXPORT_SYMBOL_GPL(scsi_device_from_queue
);
2283 * Function: scsi_block_requests()
2285 * Purpose: Utility function used by low-level drivers to prevent further
2286 * commands from being queued to the device.
2288 * Arguments: shost - Host in question
2292 * Lock status: No locks are assumed held.
2294 * Notes: There is no timer nor any other means by which the requests
2295 * get unblocked other than the low-level driver calling
2296 * scsi_unblock_requests().
2298 void scsi_block_requests(struct Scsi_Host
*shost
)
2300 shost
->host_self_blocked
= 1;
2302 EXPORT_SYMBOL(scsi_block_requests
);
2305 * Function: scsi_unblock_requests()
2307 * Purpose: Utility function used by low-level drivers to allow further
2308 * commands from being queued to the device.
2310 * Arguments: shost - Host in question
2314 * Lock status: No locks are assumed held.
2316 * Notes: There is no timer nor any other means by which the requests
2317 * get unblocked other than the low-level driver calling
2318 * scsi_unblock_requests().
2320 * This is done as an API function so that changes to the
2321 * internals of the scsi mid-layer won't require wholesale
2322 * changes to drivers that use this feature.
2324 void scsi_unblock_requests(struct Scsi_Host
*shost
)
2326 shost
->host_self_blocked
= 0;
2327 scsi_run_host_queues(shost
);
2329 EXPORT_SYMBOL(scsi_unblock_requests
);
2331 int __init
scsi_init_queue(void)
2333 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
2334 sizeof(struct scsi_data_buffer
),
2336 if (!scsi_sdb_cache
) {
2337 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
2344 void scsi_exit_queue(void)
2346 kmem_cache_destroy(scsi_sense_cache
);
2347 kmem_cache_destroy(scsi_sense_isadma_cache
);
2348 kmem_cache_destroy(scsi_sdb_cache
);
2352 * scsi_mode_select - issue a mode select
2353 * @sdev: SCSI device to be queried
2354 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2355 * @sp: Save page bit (0 == don't save, 1 == save)
2356 * @modepage: mode page being requested
2357 * @buffer: request buffer (may not be smaller than eight bytes)
2358 * @len: length of request buffer.
2359 * @timeout: command timeout
2360 * @retries: number of retries before failing
2361 * @data: returns a structure abstracting the mode header data
2362 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2363 * must be SCSI_SENSE_BUFFERSIZE big.
2365 * Returns zero if successful; negative error number or scsi
2370 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
2371 unsigned char *buffer
, int len
, int timeout
, int retries
,
2372 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2374 unsigned char cmd
[10];
2375 unsigned char *real_buffer
;
2378 memset(cmd
, 0, sizeof(cmd
));
2379 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
2381 if (sdev
->use_10_for_ms
) {
2384 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
2387 memcpy(real_buffer
+ 8, buffer
, len
);
2391 real_buffer
[2] = data
->medium_type
;
2392 real_buffer
[3] = data
->device_specific
;
2393 real_buffer
[4] = data
->longlba
? 0x01 : 0;
2395 real_buffer
[6] = data
->block_descriptor_length
>> 8;
2396 real_buffer
[7] = data
->block_descriptor_length
;
2398 cmd
[0] = MODE_SELECT_10
;
2402 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2406 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2409 memcpy(real_buffer
+ 4, buffer
, len
);
2412 real_buffer
[1] = data
->medium_type
;
2413 real_buffer
[2] = data
->device_specific
;
2414 real_buffer
[3] = data
->block_descriptor_length
;
2417 cmd
[0] = MODE_SELECT
;
2421 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2422 sshdr
, timeout
, retries
, NULL
);
2426 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2429 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2430 * @sdev: SCSI device to be queried
2431 * @dbd: set if mode sense will allow block descriptors to be returned
2432 * @modepage: mode page being requested
2433 * @buffer: request buffer (may not be smaller than eight bytes)
2434 * @len: length of request buffer.
2435 * @timeout: command timeout
2436 * @retries: number of retries before failing
2437 * @data: returns a structure abstracting the mode header data
2438 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2439 * must be SCSI_SENSE_BUFFERSIZE big.
2441 * Returns zero if unsuccessful, or the header offset (either 4
2442 * or 8 depending on whether a six or ten byte command was
2443 * issued) if successful.
2446 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2447 unsigned char *buffer
, int len
, int timeout
, int retries
,
2448 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2450 unsigned char cmd
[12];
2453 int result
, retry_count
= retries
;
2454 struct scsi_sense_hdr my_sshdr
;
2456 memset(data
, 0, sizeof(*data
));
2457 memset(&cmd
[0], 0, 12);
2458 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2461 /* caller might not be interested in sense, but we need it */
2466 use_10_for_ms
= sdev
->use_10_for_ms
;
2468 if (use_10_for_ms
) {
2472 cmd
[0] = MODE_SENSE_10
;
2479 cmd
[0] = MODE_SENSE
;
2484 memset(buffer
, 0, len
);
2486 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2487 sshdr
, timeout
, retries
, NULL
);
2489 /* This code looks awful: what it's doing is making sure an
2490 * ILLEGAL REQUEST sense return identifies the actual command
2491 * byte as the problem. MODE_SENSE commands can return
2492 * ILLEGAL REQUEST if the code page isn't supported */
2494 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2495 (driver_byte(result
) & DRIVER_SENSE
)) {
2496 if (scsi_sense_valid(sshdr
)) {
2497 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2498 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2500 * Invalid command operation code
2502 sdev
->use_10_for_ms
= 0;
2508 if(scsi_status_is_good(result
)) {
2509 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2510 (modepage
== 6 || modepage
== 8))) {
2511 /* Initio breakage? */
2514 data
->medium_type
= 0;
2515 data
->device_specific
= 0;
2517 data
->block_descriptor_length
= 0;
2518 } else if(use_10_for_ms
) {
2519 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2520 data
->medium_type
= buffer
[2];
2521 data
->device_specific
= buffer
[3];
2522 data
->longlba
= buffer
[4] & 0x01;
2523 data
->block_descriptor_length
= buffer
[6]*256
2526 data
->length
= buffer
[0] + 1;
2527 data
->medium_type
= buffer
[1];
2528 data
->device_specific
= buffer
[2];
2529 data
->block_descriptor_length
= buffer
[3];
2531 data
->header_length
= header_length
;
2532 } else if ((status_byte(result
) == CHECK_CONDITION
) &&
2533 scsi_sense_valid(sshdr
) &&
2534 sshdr
->sense_key
== UNIT_ATTENTION
&& retry_count
) {
2541 EXPORT_SYMBOL(scsi_mode_sense
);
2544 * scsi_test_unit_ready - test if unit is ready
2545 * @sdev: scsi device to change the state of.
2546 * @timeout: command timeout
2547 * @retries: number of retries before failing
2548 * @sshdr: outpout pointer for decoded sense information.
2550 * Returns zero if unsuccessful or an error if TUR failed. For
2551 * removable media, UNIT_ATTENTION sets ->changed flag.
2554 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2555 struct scsi_sense_hdr
*sshdr
)
2558 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2562 /* try to eat the UNIT_ATTENTION if there are enough retries */
2564 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2565 timeout
, retries
, NULL
);
2566 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2567 sshdr
->sense_key
== UNIT_ATTENTION
)
2569 } while (scsi_sense_valid(sshdr
) &&
2570 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2574 EXPORT_SYMBOL(scsi_test_unit_ready
);
2577 * scsi_device_set_state - Take the given device through the device state model.
2578 * @sdev: scsi device to change the state of.
2579 * @state: state to change to.
2581 * Returns zero if successful or an error if the requested
2582 * transition is illegal.
2585 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2587 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2589 if (state
== oldstate
)
2595 case SDEV_CREATED_BLOCK
:
2606 case SDEV_TRANSPORT_OFFLINE
:
2619 case SDEV_TRANSPORT_OFFLINE
:
2627 case SDEV_TRANSPORT_OFFLINE
:
2642 case SDEV_CREATED_BLOCK
:
2649 case SDEV_CREATED_BLOCK
:
2664 case SDEV_TRANSPORT_OFFLINE
:
2676 case SDEV_TRANSPORT_OFFLINE
:
2679 case SDEV_CREATED_BLOCK
:
2687 sdev
->sdev_state
= state
;
2688 sysfs_notify(&sdev
->sdev_gendev
.kobj
, NULL
, "state");
2692 SCSI_LOG_ERROR_RECOVERY(1,
2693 sdev_printk(KERN_ERR
, sdev
,
2694 "Illegal state transition %s->%s",
2695 scsi_device_state_name(oldstate
),
2696 scsi_device_state_name(state
))
2700 EXPORT_SYMBOL(scsi_device_set_state
);
2703 * sdev_evt_emit - emit a single SCSI device uevent
2704 * @sdev: associated SCSI device
2705 * @evt: event to emit
2707 * Send a single uevent (scsi_event) to the associated scsi_device.
2709 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2714 switch (evt
->evt_type
) {
2715 case SDEV_EVT_MEDIA_CHANGE
:
2716 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2718 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2719 scsi_rescan_device(&sdev
->sdev_gendev
);
2720 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2722 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2723 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2725 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2726 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2728 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2729 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2731 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2732 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2734 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2735 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2744 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2748 * sdev_evt_thread - send a uevent for each scsi event
2749 * @work: work struct for scsi_device
2751 * Dispatch queued events to their associated scsi_device kobjects
2754 void scsi_evt_thread(struct work_struct
*work
)
2756 struct scsi_device
*sdev
;
2757 enum scsi_device_event evt_type
;
2758 LIST_HEAD(event_list
);
2760 sdev
= container_of(work
, struct scsi_device
, event_work
);
2762 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2763 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2764 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2767 struct scsi_event
*evt
;
2768 struct list_head
*this, *tmp
;
2769 unsigned long flags
;
2771 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2772 list_splice_init(&sdev
->event_list
, &event_list
);
2773 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2775 if (list_empty(&event_list
))
2778 list_for_each_safe(this, tmp
, &event_list
) {
2779 evt
= list_entry(this, struct scsi_event
, node
);
2780 list_del(&evt
->node
);
2781 scsi_evt_emit(sdev
, evt
);
2788 * sdev_evt_send - send asserted event to uevent thread
2789 * @sdev: scsi_device event occurred on
2790 * @evt: event to send
2792 * Assert scsi device event asynchronously.
2794 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2796 unsigned long flags
;
2799 /* FIXME: currently this check eliminates all media change events
2800 * for polled devices. Need to update to discriminate between AN
2801 * and polled events */
2802 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2808 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2809 list_add_tail(&evt
->node
, &sdev
->event_list
);
2810 schedule_work(&sdev
->event_work
);
2811 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2813 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2816 * sdev_evt_alloc - allocate a new scsi event
2817 * @evt_type: type of event to allocate
2818 * @gfpflags: GFP flags for allocation
2820 * Allocates and returns a new scsi_event.
2822 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2825 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2829 evt
->evt_type
= evt_type
;
2830 INIT_LIST_HEAD(&evt
->node
);
2832 /* evt_type-specific initialization, if any */
2834 case SDEV_EVT_MEDIA_CHANGE
:
2835 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2836 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2837 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2838 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2839 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2840 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2848 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2851 * sdev_evt_send_simple - send asserted event to uevent thread
2852 * @sdev: scsi_device event occurred on
2853 * @evt_type: type of event to send
2854 * @gfpflags: GFP flags for allocation
2856 * Assert scsi device event asynchronously, given an event type.
2858 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2859 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2861 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2863 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2868 sdev_evt_send(sdev
, evt
);
2870 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2873 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2874 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2876 static int scsi_request_fn_active(struct scsi_device
*sdev
)
2878 struct request_queue
*q
= sdev
->request_queue
;
2879 int request_fn_active
;
2881 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2883 spin_lock_irq(q
->queue_lock
);
2884 request_fn_active
= q
->request_fn_active
;
2885 spin_unlock_irq(q
->queue_lock
);
2887 return request_fn_active
;
2891 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2892 * @sdev: SCSI device pointer.
2894 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2895 * invoked from scsi_request_fn() have finished.
2897 static void scsi_wait_for_queuecommand(struct scsi_device
*sdev
)
2899 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2901 while (scsi_request_fn_active(sdev
))
2906 * scsi_device_quiesce - Block user issued commands.
2907 * @sdev: scsi device to quiesce.
2909 * This works by trying to transition to the SDEV_QUIESCE state
2910 * (which must be a legal transition). When the device is in this
2911 * state, only special requests will be accepted, all others will
2912 * be deferred. Since special requests may also be requeued requests,
2913 * a successful return doesn't guarantee the device will be
2914 * totally quiescent.
2916 * Must be called with user context, may sleep.
2918 * Returns zero if unsuccessful or an error if not.
2921 scsi_device_quiesce(struct scsi_device
*sdev
)
2925 mutex_lock(&sdev
->state_mutex
);
2926 err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2927 mutex_unlock(&sdev
->state_mutex
);
2932 scsi_run_queue(sdev
->request_queue
);
2933 while (atomic_read(&sdev
->device_busy
)) {
2934 msleep_interruptible(200);
2935 scsi_run_queue(sdev
->request_queue
);
2939 EXPORT_SYMBOL(scsi_device_quiesce
);
2942 * scsi_device_resume - Restart user issued commands to a quiesced device.
2943 * @sdev: scsi device to resume.
2945 * Moves the device from quiesced back to running and restarts the
2948 * Must be called with user context, may sleep.
2950 void scsi_device_resume(struct scsi_device
*sdev
)
2952 /* check if the device state was mutated prior to resume, and if
2953 * so assume the state is being managed elsewhere (for example
2954 * device deleted during suspend)
2956 mutex_lock(&sdev
->state_mutex
);
2957 if (sdev
->sdev_state
== SDEV_QUIESCE
&&
2958 scsi_device_set_state(sdev
, SDEV_RUNNING
) == 0)
2959 scsi_run_queue(sdev
->request_queue
);
2960 mutex_unlock(&sdev
->state_mutex
);
2962 EXPORT_SYMBOL(scsi_device_resume
);
2965 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2967 scsi_device_quiesce(sdev
);
2971 scsi_target_quiesce(struct scsi_target
*starget
)
2973 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2975 EXPORT_SYMBOL(scsi_target_quiesce
);
2978 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2980 scsi_device_resume(sdev
);
2984 scsi_target_resume(struct scsi_target
*starget
)
2986 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2988 EXPORT_SYMBOL(scsi_target_resume
);
2991 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2992 * @sdev: device to block
2994 * Pause SCSI command processing on the specified device. Does not sleep.
2996 * Returns zero if successful or a negative error code upon failure.
2999 * This routine transitions the device to the SDEV_BLOCK state (which must be
3000 * a legal transition). When the device is in this state, command processing
3001 * is paused until the device leaves the SDEV_BLOCK state. See also
3002 * scsi_internal_device_unblock_nowait().
3004 int scsi_internal_device_block_nowait(struct scsi_device
*sdev
)
3006 struct request_queue
*q
= sdev
->request_queue
;
3007 unsigned long flags
;
3010 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
3012 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
3019 * The device has transitioned to SDEV_BLOCK. Stop the
3020 * block layer from calling the midlayer with this device's
3024 blk_mq_quiesce_queue_nowait(q
);
3026 spin_lock_irqsave(q
->queue_lock
, flags
);
3028 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3033 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait
);
3036 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
3037 * @sdev: device to block
3039 * Pause SCSI command processing on the specified device and wait until all
3040 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
3042 * Returns zero if successful or a negative error code upon failure.
3045 * This routine transitions the device to the SDEV_BLOCK state (which must be
3046 * a legal transition). When the device is in this state, command processing
3047 * is paused until the device leaves the SDEV_BLOCK state. See also
3048 * scsi_internal_device_unblock().
3050 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
3051 * scsi_internal_device_block() has blocked a SCSI device and also
3052 * remove the rport mutex lock and unlock calls from srp_queuecommand().
3054 static int scsi_internal_device_block(struct scsi_device
*sdev
)
3056 struct request_queue
*q
= sdev
->request_queue
;
3059 mutex_lock(&sdev
->state_mutex
);
3060 err
= scsi_internal_device_block_nowait(sdev
);
3063 blk_mq_quiesce_queue(q
);
3065 scsi_wait_for_queuecommand(sdev
);
3067 mutex_unlock(&sdev
->state_mutex
);
3072 void scsi_start_queue(struct scsi_device
*sdev
)
3074 struct request_queue
*q
= sdev
->request_queue
;
3075 unsigned long flags
;
3078 blk_mq_unquiesce_queue(q
);
3080 spin_lock_irqsave(q
->queue_lock
, flags
);
3082 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3087 * scsi_internal_device_unblock_nowait - resume a device after a block request
3088 * @sdev: device to resume
3089 * @new_state: state to set the device to after unblocking
3091 * Restart the device queue for a previously suspended SCSI device. Does not
3094 * Returns zero if successful or a negative error code upon failure.
3097 * This routine transitions the device to the SDEV_RUNNING state or to one of
3098 * the offline states (which must be a legal transition) allowing the midlayer
3099 * to goose the queue for this device.
3101 int scsi_internal_device_unblock_nowait(struct scsi_device
*sdev
,
3102 enum scsi_device_state new_state
)
3105 * Try to transition the scsi device to SDEV_RUNNING or one of the
3106 * offlined states and goose the device queue if successful.
3108 switch (sdev
->sdev_state
) {
3110 case SDEV_TRANSPORT_OFFLINE
:
3111 sdev
->sdev_state
= new_state
;
3112 sysfs_notify(&sdev
->sdev_gendev
.kobj
, NULL
, "state");
3114 case SDEV_CREATED_BLOCK
:
3115 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3116 new_state
== SDEV_OFFLINE
)
3117 sdev
->sdev_state
= new_state
;
3119 sdev
->sdev_state
= SDEV_CREATED
;
3120 sysfs_notify(&sdev
->sdev_gendev
.kobj
, NULL
, "state");
3128 scsi_start_queue(sdev
);
3132 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait
);
3135 * scsi_internal_device_unblock - resume a device after a block request
3136 * @sdev: device to resume
3137 * @new_state: state to set the device to after unblocking
3139 * Restart the device queue for a previously suspended SCSI device. May sleep.
3141 * Returns zero if successful or a negative error code upon failure.
3144 * This routine transitions the device to the SDEV_RUNNING state or to one of
3145 * the offline states (which must be a legal transition) allowing the midlayer
3146 * to goose the queue for this device.
3148 static int scsi_internal_device_unblock(struct scsi_device
*sdev
,
3149 enum scsi_device_state new_state
)
3153 mutex_lock(&sdev
->state_mutex
);
3154 ret
= scsi_internal_device_unblock_nowait(sdev
, new_state
);
3155 mutex_unlock(&sdev
->state_mutex
);
3161 device_block(struct scsi_device
*sdev
, void *data
)
3163 scsi_internal_device_block(sdev
);
3167 target_block(struct device
*dev
, void *data
)
3169 if (scsi_is_target_device(dev
))
3170 starget_for_each_device(to_scsi_target(dev
), NULL
,
3176 scsi_target_block(struct device
*dev
)
3178 if (scsi_is_target_device(dev
))
3179 starget_for_each_device(to_scsi_target(dev
), NULL
,
3182 device_for_each_child(dev
, NULL
, target_block
);
3184 EXPORT_SYMBOL_GPL(scsi_target_block
);
3187 device_unblock(struct scsi_device
*sdev
, void *data
)
3189 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3193 target_unblock(struct device
*dev
, void *data
)
3195 if (scsi_is_target_device(dev
))
3196 starget_for_each_device(to_scsi_target(dev
), data
,
3202 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3204 if (scsi_is_target_device(dev
))
3205 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3208 device_for_each_child(dev
, &new_state
, target_unblock
);
3210 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3213 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3214 * @sgl: scatter-gather list
3215 * @sg_count: number of segments in sg
3216 * @offset: offset in bytes into sg, on return offset into the mapped area
3217 * @len: bytes to map, on return number of bytes mapped
3219 * Returns virtual address of the start of the mapped page
3221 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3222 size_t *offset
, size_t *len
)
3225 size_t sg_len
= 0, len_complete
= 0;
3226 struct scatterlist
*sg
;
3229 WARN_ON(!irqs_disabled());
3231 for_each_sg(sgl
, sg
, sg_count
, i
) {
3232 len_complete
= sg_len
; /* Complete sg-entries */
3233 sg_len
+= sg
->length
;
3234 if (sg_len
> *offset
)
3238 if (unlikely(i
== sg_count
)) {
3239 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3241 __func__
, sg_len
, *offset
, sg_count
);
3246 /* Offset starting from the beginning of first page in this sg-entry */
3247 *offset
= *offset
- len_complete
+ sg
->offset
;
3249 /* Assumption: contiguous pages can be accessed as "page + i" */
3250 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3251 *offset
&= ~PAGE_MASK
;
3253 /* Bytes in this sg-entry from *offset to the end of the page */
3254 sg_len
= PAGE_SIZE
- *offset
;
3258 return kmap_atomic(page
);
3260 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3263 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3264 * @virt: virtual address to be unmapped
3266 void scsi_kunmap_atomic_sg(void *virt
)
3268 kunmap_atomic(virt
);
3270 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3272 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3274 atomic_inc(&sdev
->disk_events_disable_depth
);
3276 EXPORT_SYMBOL(sdev_disable_disk_events
);
3278 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3280 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3282 atomic_dec(&sdev
->disk_events_disable_depth
);
3284 EXPORT_SYMBOL(sdev_enable_disk_events
);
3287 * scsi_vpd_lun_id - return a unique device identification
3288 * @sdev: SCSI device
3289 * @id: buffer for the identification
3290 * @id_len: length of the buffer
3292 * Copies a unique device identification into @id based
3293 * on the information in the VPD page 0x83 of the device.
3294 * The string will be formatted as a SCSI name string.
3296 * Returns the length of the identification or error on failure.
3297 * If the identifier is longer than the supplied buffer the actual
3298 * identifier length is returned and the buffer is not zero-padded.
3300 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3302 u8 cur_id_type
= 0xff;
3304 const unsigned char *d
, *cur_id_str
;
3305 const struct scsi_vpd
*vpd_pg83
;
3306 int id_size
= -EINVAL
;
3309 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3316 * Look for the correct descriptor.
3317 * Order of preference for lun descriptor:
3318 * - SCSI name string
3319 * - NAA IEEE Registered Extended
3320 * - EUI-64 based 16-byte
3321 * - EUI-64 based 12-byte
3322 * - NAA IEEE Registered
3323 * - NAA IEEE Extended
3325 * as longer descriptors reduce the likelyhood
3326 * of identification clashes.
3329 /* The id string must be at least 20 bytes + terminating NULL byte */
3335 memset(id
, 0, id_len
);
3336 d
= vpd_pg83
->data
+ 4;
3337 while (d
< vpd_pg83
->data
+ vpd_pg83
->len
) {
3338 /* Skip designators not referring to the LUN */
3339 if ((d
[1] & 0x30) != 0x00)
3342 switch (d
[1] & 0xf) {
3345 if (cur_id_size
> d
[3])
3347 /* Prefer anything */
3348 if (cur_id_type
> 0x01 && cur_id_type
!= 0xff)
3351 if (cur_id_size
+ 4 > id_len
)
3352 cur_id_size
= id_len
- 4;
3354 cur_id_type
= d
[1] & 0xf;
3355 id_size
= snprintf(id
, id_len
, "t10.%*pE",
3356 cur_id_size
, cur_id_str
);
3360 if (cur_id_size
> d
[3])
3362 /* Prefer NAA IEEE Registered Extended */
3363 if (cur_id_type
== 0x3 &&
3364 cur_id_size
== d
[3])
3368 cur_id_type
= d
[1] & 0xf;
3369 switch (cur_id_size
) {
3371 id_size
= snprintf(id
, id_len
,
3376 id_size
= snprintf(id
, id_len
,
3381 id_size
= snprintf(id
, id_len
,
3392 if (cur_id_size
> d
[3])
3396 cur_id_type
= d
[1] & 0xf;
3397 switch (cur_id_size
) {
3399 id_size
= snprintf(id
, id_len
,
3404 id_size
= snprintf(id
, id_len
,
3414 /* SCSI name string */
3415 if (cur_id_size
+ 4 > d
[3])
3417 /* Prefer others for truncated descriptor */
3418 if (cur_id_size
&& d
[3] > id_len
)
3420 cur_id_size
= id_size
= d
[3];
3422 cur_id_type
= d
[1] & 0xf;
3423 if (cur_id_size
>= id_len
)
3424 cur_id_size
= id_len
- 1;
3425 memcpy(id
, cur_id_str
, cur_id_size
);
3426 /* Decrease priority for truncated descriptor */
3427 if (cur_id_size
!= id_size
)
3440 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3443 * scsi_vpd_tpg_id - return a target port group identifier
3444 * @sdev: SCSI device
3446 * Returns the Target Port Group identifier from the information
3447 * froom VPD page 0x83 of the device.
3449 * Returns the identifier or error on failure.
3451 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3453 const unsigned char *d
;
3454 const struct scsi_vpd
*vpd_pg83
;
3455 int group_id
= -EAGAIN
, rel_port
= -1;
3458 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3464 d
= vpd_pg83
->data
+ 4;
3465 while (d
< vpd_pg83
->data
+ vpd_pg83
->len
) {
3466 switch (d
[1] & 0xf) {
3468 /* Relative target port */
3469 rel_port
= get_unaligned_be16(&d
[6]);
3472 /* Target port group */
3473 group_id
= get_unaligned_be16(&d
[6]);
3482 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3487 EXPORT_SYMBOL(scsi_vpd_tpg_id
);