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_dh.h>
35 #include <trace/events/scsi.h>
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
40 static struct kmem_cache
*scsi_sdb_cache
;
41 static struct kmem_cache
*scsi_sense_cache
;
42 static struct kmem_cache
*scsi_sense_isadma_cache
;
43 static DEFINE_MUTEX(scsi_sense_cache_mutex
);
45 static inline struct kmem_cache
*
46 scsi_select_sense_cache(struct Scsi_Host
*shost
)
48 return shost
->unchecked_isa_dma
?
49 scsi_sense_isadma_cache
: scsi_sense_cache
;
52 static void scsi_free_sense_buffer(struct Scsi_Host
*shost
,
53 unsigned char *sense_buffer
)
55 kmem_cache_free(scsi_select_sense_cache(shost
), sense_buffer
);
58 static unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host
*shost
,
59 gfp_t gfp_mask
, int numa_node
)
61 return kmem_cache_alloc_node(scsi_select_sense_cache(shost
), gfp_mask
,
65 int scsi_init_sense_cache(struct Scsi_Host
*shost
)
67 struct kmem_cache
*cache
;
70 cache
= scsi_select_sense_cache(shost
);
74 mutex_lock(&scsi_sense_cache_mutex
);
75 if (shost
->unchecked_isa_dma
) {
76 scsi_sense_isadma_cache
=
77 kmem_cache_create("scsi_sense_cache(DMA)",
78 SCSI_SENSE_BUFFERSIZE
, 0,
79 SLAB_HWCACHE_ALIGN
| SLAB_CACHE_DMA
, NULL
);
80 if (!scsi_sense_isadma_cache
)
84 kmem_cache_create("scsi_sense_cache",
85 SCSI_SENSE_BUFFERSIZE
, 0, SLAB_HWCACHE_ALIGN
, NULL
);
86 if (!scsi_sense_cache
)
90 mutex_unlock(&scsi_sense_cache_mutex
);
95 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
96 * not change behaviour from the previous unplug mechanism, experimentation
97 * may prove this needs changing.
99 #define SCSI_QUEUE_DELAY 3
102 scsi_set_blocked(struct scsi_cmnd
*cmd
, int reason
)
104 struct Scsi_Host
*host
= cmd
->device
->host
;
105 struct scsi_device
*device
= cmd
->device
;
106 struct scsi_target
*starget
= scsi_target(device
);
109 * Set the appropriate busy bit for the device/host.
111 * If the host/device isn't busy, assume that something actually
112 * completed, and that we should be able to queue a command now.
114 * Note that the prior mid-layer assumption that any host could
115 * always queue at least one command is now broken. The mid-layer
116 * will implement a user specifiable stall (see
117 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
118 * if a command is requeued with no other commands outstanding
119 * either for the device or for the host.
122 case SCSI_MLQUEUE_HOST_BUSY
:
123 atomic_set(&host
->host_blocked
, host
->max_host_blocked
);
125 case SCSI_MLQUEUE_DEVICE_BUSY
:
126 case SCSI_MLQUEUE_EH_RETRY
:
127 atomic_set(&device
->device_blocked
,
128 device
->max_device_blocked
);
130 case SCSI_MLQUEUE_TARGET_BUSY
:
131 atomic_set(&starget
->target_blocked
,
132 starget
->max_target_blocked
);
137 static void scsi_mq_requeue_cmd(struct scsi_cmnd
*cmd
)
139 struct scsi_device
*sdev
= cmd
->device
;
141 blk_mq_requeue_request(cmd
->request
, true);
142 put_device(&sdev
->sdev_gendev
);
146 * __scsi_queue_insert - private queue insertion
147 * @cmd: The SCSI command being requeued
148 * @reason: The reason for the requeue
149 * @unbusy: Whether the queue should be unbusied
151 * This is a private queue insertion. The public interface
152 * scsi_queue_insert() always assumes the queue should be unbusied
153 * because it's always called before the completion. This function is
154 * for a requeue after completion, which should only occur in this
157 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
159 struct scsi_device
*device
= cmd
->device
;
160 struct request_queue
*q
= device
->request_queue
;
163 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO
, cmd
,
164 "Inserting command %p into mlqueue\n", cmd
));
166 scsi_set_blocked(cmd
, reason
);
169 * Decrement the counters, since these commands are no longer
170 * active on the host/device.
173 scsi_device_unbusy(device
);
176 * Requeue this command. It will go before all other commands
177 * that are already in the queue. Schedule requeue work under
178 * lock such that the kblockd_schedule_work() call happens
179 * before blk_cleanup_queue() finishes.
183 scsi_mq_requeue_cmd(cmd
);
186 spin_lock_irqsave(q
->queue_lock
, flags
);
187 blk_requeue_request(q
, cmd
->request
);
188 kblockd_schedule_work(&device
->requeue_work
);
189 spin_unlock_irqrestore(q
->queue_lock
, flags
);
193 * Function: scsi_queue_insert()
195 * Purpose: Insert a command in the midlevel queue.
197 * Arguments: cmd - command that we are adding to queue.
198 * reason - why we are inserting command to queue.
200 * Lock status: Assumed that lock is not held upon entry.
204 * Notes: We do this for one of two cases. Either the host is busy
205 * and it cannot accept any more commands for the time being,
206 * or the device returned QUEUE_FULL and can accept no more
208 * Notes: This could be called either from an interrupt context or a
209 * normal process context.
211 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
213 __scsi_queue_insert(cmd
, reason
, 1);
218 * scsi_execute - insert request and wait for the result
221 * @data_direction: data direction
222 * @buffer: data buffer
223 * @bufflen: len of buffer
224 * @sense: optional sense buffer
225 * @sshdr: optional decoded sense header
226 * @timeout: request timeout in seconds
227 * @retries: number of times to retry request
228 * @flags: flags for ->cmd_flags
229 * @rq_flags: flags for ->rq_flags
230 * @resid: optional residual length
232 * returns the req->errors value which is the scsi_cmnd result
235 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
236 int data_direction
, void *buffer
, unsigned bufflen
,
237 unsigned char *sense
, struct scsi_sense_hdr
*sshdr
,
238 int timeout
, int retries
, u64 flags
, req_flags_t rq_flags
,
242 struct scsi_request
*rq
;
243 int ret
= DRIVER_ERROR
<< 24;
245 req
= blk_get_request(sdev
->request_queue
,
246 data_direction
== DMA_TO_DEVICE
?
247 REQ_OP_SCSI_OUT
: REQ_OP_SCSI_IN
, __GFP_RECLAIM
);
253 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
254 buffer
, bufflen
, __GFP_RECLAIM
))
257 rq
->cmd_len
= COMMAND_SIZE(cmd
[0]);
258 memcpy(rq
->cmd
, cmd
, rq
->cmd_len
);
259 req
->retries
= retries
;
260 req
->timeout
= timeout
;
261 req
->cmd_flags
|= flags
;
262 req
->rq_flags
|= rq_flags
| RQF_QUIET
| RQF_PREEMPT
;
265 * head injection *required* here otherwise quiesce won't work
267 blk_execute_rq(req
->q
, NULL
, req
, 1);
270 * Some devices (USB mass-storage in particular) may transfer
271 * garbage data together with a residue indicating that the data
272 * is invalid. Prevent the garbage from being misinterpreted
273 * and prevent security leaks by zeroing out the excess data.
275 if (unlikely(rq
->resid_len
> 0 && rq
->resid_len
<= bufflen
))
276 memset(buffer
+ (bufflen
- rq
->resid_len
), 0, rq
->resid_len
);
279 *resid
= rq
->resid_len
;
280 if (sense
&& rq
->sense_len
)
281 memcpy(sense
, rq
->sense
, SCSI_SENSE_BUFFERSIZE
);
283 scsi_normalize_sense(rq
->sense
, rq
->sense_len
, sshdr
);
286 blk_put_request(req
);
290 EXPORT_SYMBOL(scsi_execute
);
293 * Function: scsi_init_cmd_errh()
295 * Purpose: Initialize cmd fields related to error handling.
297 * Arguments: cmd - command that is ready to be queued.
299 * Notes: This function has the job of initializing a number of
300 * fields related to error handling. Typically this will
301 * be called once for each command, as required.
303 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
305 cmd
->serial_number
= 0;
306 scsi_set_resid(cmd
, 0);
307 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
308 if (cmd
->cmd_len
== 0)
309 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
312 void scsi_device_unbusy(struct scsi_device
*sdev
)
314 struct Scsi_Host
*shost
= sdev
->host
;
315 struct scsi_target
*starget
= scsi_target(sdev
);
318 atomic_dec(&shost
->host_busy
);
319 if (starget
->can_queue
> 0)
320 atomic_dec(&starget
->target_busy
);
322 if (unlikely(scsi_host_in_recovery(shost
) &&
323 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
324 spin_lock_irqsave(shost
->host_lock
, flags
);
325 scsi_eh_wakeup(shost
);
326 spin_unlock_irqrestore(shost
->host_lock
, flags
);
329 atomic_dec(&sdev
->device_busy
);
332 static void scsi_kick_queue(struct request_queue
*q
)
335 blk_mq_start_hw_queues(q
);
341 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
342 * and call blk_run_queue for all the scsi_devices on the target -
343 * including current_sdev first.
345 * Called with *no* scsi locks held.
347 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
349 struct Scsi_Host
*shost
= current_sdev
->host
;
350 struct scsi_device
*sdev
, *tmp
;
351 struct scsi_target
*starget
= scsi_target(current_sdev
);
354 spin_lock_irqsave(shost
->host_lock
, flags
);
355 starget
->starget_sdev_user
= NULL
;
356 spin_unlock_irqrestore(shost
->host_lock
, flags
);
359 * Call blk_run_queue for all LUNs on the target, starting with
360 * current_sdev. We race with others (to set starget_sdev_user),
361 * but in most cases, we will be first. Ideally, each LU on the
362 * target would get some limited time or requests on the target.
364 scsi_kick_queue(current_sdev
->request_queue
);
366 spin_lock_irqsave(shost
->host_lock
, flags
);
367 if (starget
->starget_sdev_user
)
369 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
370 same_target_siblings
) {
371 if (sdev
== current_sdev
)
373 if (scsi_device_get(sdev
))
376 spin_unlock_irqrestore(shost
->host_lock
, flags
);
377 scsi_kick_queue(sdev
->request_queue
);
378 spin_lock_irqsave(shost
->host_lock
, flags
);
380 scsi_device_put(sdev
);
383 spin_unlock_irqrestore(shost
->host_lock
, flags
);
386 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
388 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
390 if (atomic_read(&sdev
->device_blocked
) > 0)
395 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
397 if (starget
->can_queue
> 0) {
398 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
400 if (atomic_read(&starget
->target_blocked
) > 0)
406 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
408 if (shost
->can_queue
> 0 &&
409 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
411 if (atomic_read(&shost
->host_blocked
) > 0)
413 if (shost
->host_self_blocked
)
418 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
420 LIST_HEAD(starved_list
);
421 struct scsi_device
*sdev
;
424 spin_lock_irqsave(shost
->host_lock
, flags
);
425 list_splice_init(&shost
->starved_list
, &starved_list
);
427 while (!list_empty(&starved_list
)) {
428 struct request_queue
*slq
;
431 * As long as shost is accepting commands and we have
432 * starved queues, call blk_run_queue. scsi_request_fn
433 * drops the queue_lock and can add us back to the
436 * host_lock protects the starved_list and starved_entry.
437 * scsi_request_fn must get the host_lock before checking
438 * or modifying starved_list or starved_entry.
440 if (scsi_host_is_busy(shost
))
443 sdev
= list_entry(starved_list
.next
,
444 struct scsi_device
, starved_entry
);
445 list_del_init(&sdev
->starved_entry
);
446 if (scsi_target_is_busy(scsi_target(sdev
))) {
447 list_move_tail(&sdev
->starved_entry
,
448 &shost
->starved_list
);
453 * Once we drop the host lock, a racing scsi_remove_device()
454 * call may remove the sdev from the starved list and destroy
455 * it and the queue. Mitigate by taking a reference to the
456 * queue and never touching the sdev again after we drop the
457 * host lock. Note: if __scsi_remove_device() invokes
458 * blk_cleanup_queue() before the queue is run from this
459 * function then blk_run_queue() will return immediately since
460 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
462 slq
= sdev
->request_queue
;
463 if (!blk_get_queue(slq
))
465 spin_unlock_irqrestore(shost
->host_lock
, flags
);
467 scsi_kick_queue(slq
);
470 spin_lock_irqsave(shost
->host_lock
, flags
);
472 /* put any unprocessed entries back */
473 list_splice(&starved_list
, &shost
->starved_list
);
474 spin_unlock_irqrestore(shost
->host_lock
, flags
);
478 * Function: scsi_run_queue()
480 * Purpose: Select a proper request queue to serve next
482 * Arguments: q - last request's queue
486 * Notes: The previous command was completely finished, start
487 * a new one if possible.
489 static void scsi_run_queue(struct request_queue
*q
)
491 struct scsi_device
*sdev
= q
->queuedata
;
493 if (scsi_target(sdev
)->single_lun
)
494 scsi_single_lun_run(sdev
);
495 if (!list_empty(&sdev
->host
->starved_list
))
496 scsi_starved_list_run(sdev
->host
);
499 blk_mq_start_stopped_hw_queues(q
, false);
504 void scsi_requeue_run_queue(struct work_struct
*work
)
506 struct scsi_device
*sdev
;
507 struct request_queue
*q
;
509 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
510 q
= sdev
->request_queue
;
515 * Function: scsi_requeue_command()
517 * Purpose: Handle post-processing of completed commands.
519 * Arguments: q - queue to operate on
520 * cmd - command that may need to be requeued.
524 * Notes: After command completion, there may be blocks left
525 * over which weren't finished by the previous command
526 * this can be for a number of reasons - the main one is
527 * I/O errors in the middle of the request, in which case
528 * we need to request the blocks that come after the bad
530 * Notes: Upon return, cmd is a stale pointer.
532 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
534 struct scsi_device
*sdev
= cmd
->device
;
535 struct request
*req
= cmd
->request
;
538 spin_lock_irqsave(q
->queue_lock
, flags
);
539 blk_unprep_request(req
);
541 scsi_put_command(cmd
);
542 blk_requeue_request(q
, req
);
543 spin_unlock_irqrestore(q
->queue_lock
, flags
);
547 put_device(&sdev
->sdev_gendev
);
550 void scsi_run_host_queues(struct Scsi_Host
*shost
)
552 struct scsi_device
*sdev
;
554 shost_for_each_device(sdev
, shost
)
555 scsi_run_queue(sdev
->request_queue
);
558 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
560 if (!blk_rq_is_passthrough(cmd
->request
)) {
561 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
563 if (drv
->uninit_command
)
564 drv
->uninit_command(cmd
);
568 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
570 struct scsi_data_buffer
*sdb
;
572 if (cmd
->sdb
.table
.nents
)
573 sg_free_table_chained(&cmd
->sdb
.table
, true);
574 if (cmd
->request
->next_rq
) {
575 sdb
= cmd
->request
->next_rq
->special
;
577 sg_free_table_chained(&sdb
->table
, true);
579 if (scsi_prot_sg_count(cmd
))
580 sg_free_table_chained(&cmd
->prot_sdb
->table
, true);
583 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
585 struct scsi_device
*sdev
= cmd
->device
;
586 struct Scsi_Host
*shost
= sdev
->host
;
589 scsi_mq_free_sgtables(cmd
);
590 scsi_uninit_cmd(cmd
);
592 if (shost
->use_cmd_list
) {
593 BUG_ON(list_empty(&cmd
->list
));
594 spin_lock_irqsave(&sdev
->list_lock
, flags
);
595 list_del_init(&cmd
->list
);
596 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
601 * Function: scsi_release_buffers()
603 * Purpose: Free resources allocate for a scsi_command.
605 * Arguments: cmd - command that we are bailing.
607 * Lock status: Assumed that no lock is held upon entry.
611 * Notes: In the event that an upper level driver rejects a
612 * command, we must release resources allocated during
613 * the __init_io() function. Primarily this would involve
614 * the scatter-gather table.
616 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
618 if (cmd
->sdb
.table
.nents
)
619 sg_free_table_chained(&cmd
->sdb
.table
, false);
621 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
623 if (scsi_prot_sg_count(cmd
))
624 sg_free_table_chained(&cmd
->prot_sdb
->table
, false);
627 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
629 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
631 sg_free_table_chained(&bidi_sdb
->table
, false);
632 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
633 cmd
->request
->next_rq
->special
= NULL
;
636 static bool scsi_end_request(struct request
*req
, int error
,
637 unsigned int bytes
, unsigned int bidi_bytes
)
639 struct scsi_cmnd
*cmd
= req
->special
;
640 struct scsi_device
*sdev
= cmd
->device
;
641 struct request_queue
*q
= sdev
->request_queue
;
643 if (blk_update_request(req
, error
, bytes
))
646 /* Bidi request must be completed as a whole */
647 if (unlikely(bidi_bytes
) &&
648 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
651 if (blk_queue_add_random(q
))
652 add_disk_randomness(req
->rq_disk
);
656 * In the MQ case the command gets freed by __blk_mq_end_request,
657 * so we have to do all cleanup that depends on it earlier.
659 * We also can't kick the queues from irq context, so we
660 * will have to defer it to a workqueue.
662 scsi_mq_uninit_cmd(cmd
);
664 __blk_mq_end_request(req
, error
);
666 if (scsi_target(sdev
)->single_lun
||
667 !list_empty(&sdev
->host
->starved_list
))
668 kblockd_schedule_work(&sdev
->requeue_work
);
670 blk_mq_start_stopped_hw_queues(q
, true);
675 scsi_release_bidi_buffers(cmd
);
676 scsi_release_buffers(cmd
);
677 scsi_put_command(cmd
);
679 spin_lock_irqsave(q
->queue_lock
, flags
);
680 blk_finish_request(req
, error
);
681 spin_unlock_irqrestore(q
->queue_lock
, flags
);
686 put_device(&sdev
->sdev_gendev
);
691 * __scsi_error_from_host_byte - translate SCSI error code into errno
692 * @cmd: SCSI command (unused)
693 * @result: scsi error code
695 * Translate SCSI error code into standard UNIX errno.
697 * -ENOLINK temporary transport failure
698 * -EREMOTEIO permanent target failure, do not retry
699 * -EBADE permanent nexus failure, retry on other path
700 * -ENOSPC No write space available
701 * -ENODATA Medium error
702 * -EIO unspecified I/O error
704 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
708 switch(host_byte(result
)) {
709 case DID_TRANSPORT_FAILFAST
:
712 case DID_TARGET_FAILURE
:
713 set_host_byte(cmd
, DID_OK
);
716 case DID_NEXUS_FAILURE
:
717 set_host_byte(cmd
, DID_OK
);
720 case DID_ALLOC_FAILURE
:
721 set_host_byte(cmd
, DID_OK
);
724 case DID_MEDIUM_ERROR
:
725 set_host_byte(cmd
, DID_OK
);
737 * Function: scsi_io_completion()
739 * Purpose: Completion processing for block device I/O requests.
741 * Arguments: cmd - command that is finished.
743 * Lock status: Assumed that no lock is held upon entry.
747 * Notes: We will finish off the specified number of sectors. If we
748 * are done, the command block will be released and the queue
749 * function will be goosed. If we are not done then we have to
750 * figure out what to do next:
752 * a) We can call scsi_requeue_command(). The request
753 * will be unprepared and put back on the queue. Then
754 * a new command will be created for it. This should
755 * be used if we made forward progress, or if we want
756 * to switch from READ(10) to READ(6) for example.
758 * b) We can call __scsi_queue_insert(). The request will
759 * be put back on the queue and retried using the same
760 * command as before, possibly after a delay.
762 * c) We can call scsi_end_request() with -EIO to fail
763 * the remainder of the request.
765 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
767 int result
= cmd
->result
;
768 struct request_queue
*q
= cmd
->device
->request_queue
;
769 struct request
*req
= cmd
->request
;
771 struct scsi_sense_hdr sshdr
;
772 bool sense_valid
= false;
773 int sense_deferred
= 0, level
= 0;
774 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
775 ACTION_DELAYED_RETRY
} action
;
776 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
779 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
781 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
784 if (blk_rq_is_passthrough(req
)) {
788 * SG_IO wants current and deferred errors
790 scsi_req(req
)->sense_len
=
791 min(8 + cmd
->sense_buffer
[7],
792 SCSI_SENSE_BUFFERSIZE
);
795 error
= __scsi_error_from_host_byte(cmd
, result
);
798 * __scsi_error_from_host_byte may have reset the host_byte
800 req
->errors
= cmd
->result
;
802 scsi_req(req
)->resid_len
= scsi_get_resid(cmd
);
804 if (scsi_bidi_cmnd(cmd
)) {
806 * Bidi commands Must be complete as a whole,
807 * both sides at once.
809 scsi_req(req
->next_rq
)->resid_len
= scsi_in(cmd
)->resid
;
810 if (scsi_end_request(req
, 0, blk_rq_bytes(req
),
811 blk_rq_bytes(req
->next_rq
)))
815 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
817 * Flush commands do not transfers any data, and thus cannot use
818 * good_bytes != blk_rq_bytes(req) as the signal for an error.
819 * This sets the error explicitly for the problem case.
821 error
= __scsi_error_from_host_byte(cmd
, result
);
824 /* no bidi support for !blk_rq_is_passthrough yet */
825 BUG_ON(blk_bidi_rq(req
));
828 * Next deal with any sectors which we were able to correctly
831 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO
, cmd
,
832 "%u sectors total, %d bytes done.\n",
833 blk_rq_sectors(req
), good_bytes
));
836 * Recovered errors need reporting, but they're always treated as
837 * success, so fiddle the result code here. For passthrough requests
838 * we already took a copy of the original into rq->errors which
839 * is what gets returned to the user
841 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
842 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
843 * print since caller wants ATA registers. Only occurs on
844 * SCSI ATA PASS_THROUGH commands when CK_COND=1
846 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
848 else if (!(req
->rq_flags
& RQF_QUIET
))
849 scsi_print_sense(cmd
);
851 /* for passthrough error may be set */
856 * special case: failed zero length commands always need to
857 * drop down into the retry code. Otherwise, if we finished
858 * all bytes in the request we are done now.
860 if (!(blk_rq_bytes(req
) == 0 && error
) &&
861 !scsi_end_request(req
, error
, good_bytes
, 0))
865 * Kill remainder if no retrys.
867 if (error
&& scsi_noretry_cmd(cmd
)) {
868 if (scsi_end_request(req
, error
, blk_rq_bytes(req
), 0))
874 * If there had been no error, but we have leftover bytes in the
875 * requeues just queue the command up again.
880 error
= __scsi_error_from_host_byte(cmd
, result
);
882 if (host_byte(result
) == DID_RESET
) {
883 /* Third party bus reset or reset for error recovery
884 * reasons. Just retry the command and see what
887 action
= ACTION_RETRY
;
888 } else if (sense_valid
&& !sense_deferred
) {
889 switch (sshdr
.sense_key
) {
891 if (cmd
->device
->removable
) {
892 /* Detected disc change. Set a bit
893 * and quietly refuse further access.
895 cmd
->device
->changed
= 1;
896 action
= ACTION_FAIL
;
898 /* Must have been a power glitch, or a
899 * bus reset. Could not have been a
900 * media change, so we just retry the
901 * command and see what happens.
903 action
= ACTION_RETRY
;
906 case ILLEGAL_REQUEST
:
907 /* If we had an ILLEGAL REQUEST returned, then
908 * we may have performed an unsupported
909 * command. The only thing this should be
910 * would be a ten byte read where only a six
911 * byte read was supported. Also, on a system
912 * where READ CAPACITY failed, we may have
913 * read past the end of the disk.
915 if ((cmd
->device
->use_10_for_rw
&&
916 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
917 (cmd
->cmnd
[0] == READ_10
||
918 cmd
->cmnd
[0] == WRITE_10
)) {
919 /* This will issue a new 6-byte command. */
920 cmd
->device
->use_10_for_rw
= 0;
921 action
= ACTION_REPREP
;
922 } else if (sshdr
.asc
== 0x10) /* DIX */ {
923 action
= ACTION_FAIL
;
925 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
926 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
927 action
= ACTION_FAIL
;
930 action
= ACTION_FAIL
;
932 case ABORTED_COMMAND
:
933 action
= ACTION_FAIL
;
934 if (sshdr
.asc
== 0x10) /* DIF */
938 /* If the device is in the process of becoming
939 * ready, or has a temporary blockage, retry.
941 if (sshdr
.asc
== 0x04) {
942 switch (sshdr
.ascq
) {
943 case 0x01: /* becoming ready */
944 case 0x04: /* format in progress */
945 case 0x05: /* rebuild in progress */
946 case 0x06: /* recalculation in progress */
947 case 0x07: /* operation in progress */
948 case 0x08: /* Long write in progress */
949 case 0x09: /* self test in progress */
950 case 0x14: /* space allocation in progress */
951 action
= ACTION_DELAYED_RETRY
;
954 action
= ACTION_FAIL
;
958 action
= ACTION_FAIL
;
960 case VOLUME_OVERFLOW
:
961 /* See SSC3rXX or current. */
962 action
= ACTION_FAIL
;
965 action
= ACTION_FAIL
;
969 action
= ACTION_FAIL
;
971 if (action
!= ACTION_FAIL
&&
972 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
))
973 action
= ACTION_FAIL
;
977 /* Give up and fail the remainder of the request */
978 if (!(req
->rq_flags
& RQF_QUIET
)) {
979 static DEFINE_RATELIMIT_STATE(_rs
,
980 DEFAULT_RATELIMIT_INTERVAL
,
981 DEFAULT_RATELIMIT_BURST
);
983 if (unlikely(scsi_logging_level
))
984 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
985 SCSI_LOG_MLCOMPLETE_BITS
);
988 * if logging is enabled the failure will be printed
989 * in scsi_log_completion(), so avoid duplicate messages
991 if (!level
&& __ratelimit(&_rs
)) {
992 scsi_print_result(cmd
, NULL
, FAILED
);
993 if (driver_byte(result
) & DRIVER_SENSE
)
994 scsi_print_sense(cmd
);
995 scsi_print_command(cmd
);
998 if (!scsi_end_request(req
, error
, blk_rq_err_bytes(req
), 0))
1003 /* Unprep the request and put it back at the head of the queue.
1004 * A new command will be prepared and issued.
1007 cmd
->request
->rq_flags
&= ~RQF_DONTPREP
;
1008 scsi_mq_uninit_cmd(cmd
);
1009 scsi_mq_requeue_cmd(cmd
);
1011 scsi_release_buffers(cmd
);
1012 scsi_requeue_command(q
, cmd
);
1016 /* Retry the same command immediately */
1017 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1019 case ACTION_DELAYED_RETRY
:
1020 /* Retry the same command after a delay */
1021 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1026 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
)
1031 * If sg table allocation fails, requeue request later.
1033 if (unlikely(sg_alloc_table_chained(&sdb
->table
,
1034 blk_rq_nr_phys_segments(req
), sdb
->table
.sgl
)))
1035 return BLKPREP_DEFER
;
1038 * Next, walk the list, and fill in the addresses and sizes of
1041 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1042 BUG_ON(count
> sdb
->table
.nents
);
1043 sdb
->table
.nents
= count
;
1044 sdb
->length
= blk_rq_payload_bytes(req
);
1049 * Function: scsi_init_io()
1051 * Purpose: SCSI I/O initialize function.
1053 * Arguments: cmd - Command descriptor we wish to initialize
1055 * Returns: 0 on success
1056 * BLKPREP_DEFER if the failure is retryable
1057 * BLKPREP_KILL if the failure is fatal
1059 int scsi_init_io(struct scsi_cmnd
*cmd
)
1061 struct scsi_device
*sdev
= cmd
->device
;
1062 struct request
*rq
= cmd
->request
;
1063 bool is_mq
= (rq
->mq_ctx
!= NULL
);
1066 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq
)))
1069 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1073 if (blk_bidi_rq(rq
)) {
1074 if (!rq
->q
->mq_ops
) {
1075 struct scsi_data_buffer
*bidi_sdb
=
1076 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1078 error
= BLKPREP_DEFER
;
1082 rq
->next_rq
->special
= bidi_sdb
;
1085 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1090 if (blk_integrity_rq(rq
)) {
1091 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1094 if (prot_sdb
== NULL
) {
1096 * This can happen if someone (e.g. multipath)
1097 * queues a command to a device on an adapter
1098 * that does not support DIX.
1101 error
= BLKPREP_KILL
;
1105 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1107 if (sg_alloc_table_chained(&prot_sdb
->table
, ivecs
,
1108 prot_sdb
->table
.sgl
)) {
1109 error
= BLKPREP_DEFER
;
1113 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1114 prot_sdb
->table
.sgl
);
1115 BUG_ON(unlikely(count
> ivecs
));
1116 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1118 cmd
->prot_sdb
= prot_sdb
;
1119 cmd
->prot_sdb
->table
.nents
= count
;
1125 scsi_mq_free_sgtables(cmd
);
1127 scsi_release_buffers(cmd
);
1128 cmd
->request
->special
= NULL
;
1129 scsi_put_command(cmd
);
1130 put_device(&sdev
->sdev_gendev
);
1134 EXPORT_SYMBOL(scsi_init_io
);
1136 void scsi_init_command(struct scsi_device
*dev
, struct scsi_cmnd
*cmd
)
1138 void *buf
= cmd
->sense_buffer
;
1139 void *prot
= cmd
->prot_sdb
;
1140 unsigned long flags
;
1142 /* zero out the cmd, except for the embedded scsi_request */
1143 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1144 sizeof(*cmd
) - sizeof(cmd
->req
) + dev
->host
->hostt
->cmd_size
);
1147 cmd
->sense_buffer
= buf
;
1148 cmd
->prot_sdb
= prot
;
1149 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1150 cmd
->jiffies_at_alloc
= jiffies
;
1152 spin_lock_irqsave(&dev
->list_lock
, flags
);
1153 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
1154 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
1157 static int scsi_setup_scsi_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1159 struct scsi_cmnd
*cmd
= req
->special
;
1162 * Passthrough requests may transfer data, in which case they must
1163 * a bio attached to them. Or they might contain a SCSI command
1164 * that does not transfer data, in which case they may optionally
1165 * submit a request without an attached bio.
1168 int ret
= scsi_init_io(cmd
);
1172 BUG_ON(blk_rq_bytes(req
));
1174 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1177 cmd
->cmd_len
= scsi_req(req
)->cmd_len
;
1178 cmd
->cmnd
= scsi_req(req
)->cmd
;
1179 cmd
->transfersize
= blk_rq_bytes(req
);
1180 cmd
->allowed
= req
->retries
;
1185 * Setup a normal block command. These are simple request from filesystems
1186 * that still need to be translated to SCSI CDBs from the ULD.
1188 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1190 struct scsi_cmnd
*cmd
= req
->special
;
1192 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1193 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1194 if (ret
!= BLKPREP_OK
)
1198 cmd
->cmnd
= scsi_req(req
)->cmd
= scsi_req(req
)->__cmd
;
1199 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1200 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1203 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1205 struct scsi_cmnd
*cmd
= req
->special
;
1207 if (!blk_rq_bytes(req
))
1208 cmd
->sc_data_direction
= DMA_NONE
;
1209 else if (rq_data_dir(req
) == WRITE
)
1210 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1212 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1214 if (blk_rq_is_scsi(req
))
1215 return scsi_setup_scsi_cmnd(sdev
, req
);
1217 return scsi_setup_fs_cmnd(sdev
, req
);
1221 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1223 int ret
= BLKPREP_OK
;
1226 * If the device is not in running state we will reject some
1229 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1230 switch (sdev
->sdev_state
) {
1232 case SDEV_TRANSPORT_OFFLINE
:
1234 * If the device is offline we refuse to process any
1235 * commands. The device must be brought online
1236 * before trying any recovery commands.
1238 sdev_printk(KERN_ERR
, sdev
,
1239 "rejecting I/O to offline device\n");
1244 * If the device is fully deleted, we refuse to
1245 * process any commands as well.
1247 sdev_printk(KERN_ERR
, sdev
,
1248 "rejecting I/O to dead device\n");
1252 case SDEV_CREATED_BLOCK
:
1253 ret
= BLKPREP_DEFER
;
1257 * If the devices is blocked we defer normal commands.
1259 if (!(req
->rq_flags
& RQF_PREEMPT
))
1260 ret
= BLKPREP_DEFER
;
1264 * For any other not fully online state we only allow
1265 * special commands. In particular any user initiated
1266 * command is not allowed.
1268 if (!(req
->rq_flags
& RQF_PREEMPT
))
1277 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1279 struct scsi_device
*sdev
= q
->queuedata
;
1283 case BLKPREP_INVALID
:
1284 req
->errors
= DID_NO_CONNECT
<< 16;
1285 /* release the command and kill it */
1287 struct scsi_cmnd
*cmd
= req
->special
;
1288 scsi_release_buffers(cmd
);
1289 scsi_put_command(cmd
);
1290 put_device(&sdev
->sdev_gendev
);
1291 req
->special
= NULL
;
1296 * If we defer, the blk_peek_request() returns NULL, but the
1297 * queue must be restarted, so we schedule a callback to happen
1300 if (atomic_read(&sdev
->device_busy
) == 0)
1301 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1304 req
->rq_flags
|= RQF_DONTPREP
;
1310 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1312 struct scsi_device
*sdev
= q
->queuedata
;
1313 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1316 ret
= scsi_prep_state_check(sdev
, req
);
1317 if (ret
!= BLKPREP_OK
)
1320 if (!req
->special
) {
1321 /* Bail if we can't get a reference to the device */
1322 if (unlikely(!get_device(&sdev
->sdev_gendev
))) {
1323 ret
= BLKPREP_DEFER
;
1327 scsi_init_command(sdev
, cmd
);
1331 cmd
->tag
= req
->tag
;
1333 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1335 ret
= scsi_setup_cmnd(sdev
, req
);
1337 return scsi_prep_return(q
, req
, ret
);
1340 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1342 scsi_uninit_cmd(req
->special
);
1346 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1349 * Called with the queue_lock held.
1351 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1352 struct scsi_device
*sdev
)
1356 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1357 if (atomic_read(&sdev
->device_blocked
)) {
1362 * unblock after device_blocked iterates to zero
1364 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1366 * For the MQ case we take care of this in the caller.
1369 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1372 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1373 "unblocking device at zero depth\n"));
1376 if (busy
>= sdev
->queue_depth
)
1381 atomic_dec(&sdev
->device_busy
);
1386 * scsi_target_queue_ready: checks if there we can send commands to target
1387 * @sdev: scsi device on starget to check.
1389 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1390 struct scsi_device
*sdev
)
1392 struct scsi_target
*starget
= scsi_target(sdev
);
1395 if (starget
->single_lun
) {
1396 spin_lock_irq(shost
->host_lock
);
1397 if (starget
->starget_sdev_user
&&
1398 starget
->starget_sdev_user
!= sdev
) {
1399 spin_unlock_irq(shost
->host_lock
);
1402 starget
->starget_sdev_user
= sdev
;
1403 spin_unlock_irq(shost
->host_lock
);
1406 if (starget
->can_queue
<= 0)
1409 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1410 if (atomic_read(&starget
->target_blocked
) > 0) {
1415 * unblock after target_blocked iterates to zero
1417 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1420 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1421 "unblocking target at zero depth\n"));
1424 if (busy
>= starget
->can_queue
)
1430 spin_lock_irq(shost
->host_lock
);
1431 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1432 spin_unlock_irq(shost
->host_lock
);
1434 if (starget
->can_queue
> 0)
1435 atomic_dec(&starget
->target_busy
);
1440 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1441 * return 0. We must end up running the queue again whenever 0 is
1442 * returned, else IO can hang.
1444 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1445 struct Scsi_Host
*shost
,
1446 struct scsi_device
*sdev
)
1450 if (scsi_host_in_recovery(shost
))
1453 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1454 if (atomic_read(&shost
->host_blocked
) > 0) {
1459 * unblock after host_blocked iterates to zero
1461 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1465 shost_printk(KERN_INFO
, shost
,
1466 "unblocking host at zero depth\n"));
1469 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1471 if (shost
->host_self_blocked
)
1474 /* We're OK to process the command, so we can't be starved */
1475 if (!list_empty(&sdev
->starved_entry
)) {
1476 spin_lock_irq(shost
->host_lock
);
1477 if (!list_empty(&sdev
->starved_entry
))
1478 list_del_init(&sdev
->starved_entry
);
1479 spin_unlock_irq(shost
->host_lock
);
1485 spin_lock_irq(shost
->host_lock
);
1486 if (list_empty(&sdev
->starved_entry
))
1487 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1488 spin_unlock_irq(shost
->host_lock
);
1490 atomic_dec(&shost
->host_busy
);
1495 * Busy state exporting function for request stacking drivers.
1497 * For efficiency, no lock is taken to check the busy state of
1498 * shost/starget/sdev, since the returned value is not guaranteed and
1499 * may be changed after request stacking drivers call the function,
1500 * regardless of taking lock or not.
1502 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1503 * needs to return 'not busy'. Otherwise, request stacking drivers
1504 * may hold requests forever.
1506 static int scsi_lld_busy(struct request_queue
*q
)
1508 struct scsi_device
*sdev
= q
->queuedata
;
1509 struct Scsi_Host
*shost
;
1511 if (blk_queue_dying(q
))
1517 * Ignore host/starget busy state.
1518 * Since block layer does not have a concept of fairness across
1519 * multiple queues, congestion of host/starget needs to be handled
1522 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1529 * Kill a request for a dead device
1531 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1533 struct scsi_cmnd
*cmd
= req
->special
;
1534 struct scsi_device
*sdev
;
1535 struct scsi_target
*starget
;
1536 struct Scsi_Host
*shost
;
1538 blk_start_request(req
);
1540 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1543 starget
= scsi_target(sdev
);
1545 scsi_init_cmd_errh(cmd
);
1546 cmd
->result
= DID_NO_CONNECT
<< 16;
1547 atomic_inc(&cmd
->device
->iorequest_cnt
);
1550 * SCSI request completion path will do scsi_device_unbusy(),
1551 * bump busy counts. To bump the counters, we need to dance
1552 * with the locks as normal issue path does.
1554 atomic_inc(&sdev
->device_busy
);
1555 atomic_inc(&shost
->host_busy
);
1556 if (starget
->can_queue
> 0)
1557 atomic_inc(&starget
->target_busy
);
1559 blk_complete_request(req
);
1562 static void scsi_softirq_done(struct request
*rq
)
1564 struct scsi_cmnd
*cmd
= rq
->special
;
1565 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1568 INIT_LIST_HEAD(&cmd
->eh_entry
);
1570 atomic_inc(&cmd
->device
->iodone_cnt
);
1572 atomic_inc(&cmd
->device
->ioerr_cnt
);
1574 disposition
= scsi_decide_disposition(cmd
);
1575 if (disposition
!= SUCCESS
&&
1576 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1577 sdev_printk(KERN_ERR
, cmd
->device
,
1578 "timing out command, waited %lus\n",
1580 disposition
= SUCCESS
;
1583 scsi_log_completion(cmd
, disposition
);
1585 switch (disposition
) {
1587 scsi_finish_command(cmd
);
1590 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1592 case ADD_TO_MLQUEUE
:
1593 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1596 if (!scsi_eh_scmd_add(cmd
, 0))
1597 scsi_finish_command(cmd
);
1602 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1603 * @cmd: command block we are dispatching.
1605 * Return: nonzero return request was rejected and device's queue needs to be
1608 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1610 struct Scsi_Host
*host
= cmd
->device
->host
;
1613 atomic_inc(&cmd
->device
->iorequest_cnt
);
1615 /* check if the device is still usable */
1616 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1617 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1618 * returns an immediate error upwards, and signals
1619 * that the device is no longer present */
1620 cmd
->result
= DID_NO_CONNECT
<< 16;
1624 /* Check to see if the scsi lld made this device blocked. */
1625 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1627 * in blocked state, the command is just put back on
1628 * the device queue. The suspend state has already
1629 * blocked the queue so future requests should not
1630 * occur until the device transitions out of the
1633 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1634 "queuecommand : device blocked\n"));
1635 return SCSI_MLQUEUE_DEVICE_BUSY
;
1638 /* Store the LUN value in cmnd, if needed. */
1639 if (cmd
->device
->lun_in_cdb
)
1640 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1641 (cmd
->device
->lun
<< 5 & 0xe0);
1646 * Before we queue this command, check if the command
1647 * length exceeds what the host adapter can handle.
1649 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1650 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1651 "queuecommand : command too long. "
1652 "cdb_size=%d host->max_cmd_len=%d\n",
1653 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1654 cmd
->result
= (DID_ABORT
<< 16);
1658 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1659 cmd
->result
= (DID_NO_CONNECT
<< 16);
1664 trace_scsi_dispatch_cmd_start(cmd
);
1665 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1667 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1668 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1669 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1670 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1672 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1673 "queuecommand : request rejected\n"));
1678 cmd
->scsi_done(cmd
);
1683 * scsi_done - Invoke completion on finished SCSI command.
1684 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1685 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1687 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1688 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1689 * calls blk_complete_request() for further processing.
1691 * This function is interrupt context safe.
1693 static void scsi_done(struct scsi_cmnd
*cmd
)
1695 trace_scsi_dispatch_cmd_done(cmd
);
1696 blk_complete_request(cmd
->request
);
1700 * Function: scsi_request_fn()
1702 * Purpose: Main strategy routine for SCSI.
1704 * Arguments: q - Pointer to actual queue.
1708 * Lock status: IO request lock assumed to be held when called.
1710 static void scsi_request_fn(struct request_queue
*q
)
1711 __releases(q
->queue_lock
)
1712 __acquires(q
->queue_lock
)
1714 struct scsi_device
*sdev
= q
->queuedata
;
1715 struct Scsi_Host
*shost
;
1716 struct scsi_cmnd
*cmd
;
1717 struct request
*req
;
1720 * To start with, we keep looping until the queue is empty, or until
1721 * the host is no longer able to accept any more requests.
1727 * get next queueable request. We do this early to make sure
1728 * that the request is fully prepared even if we cannot
1731 req
= blk_peek_request(q
);
1735 if (unlikely(!scsi_device_online(sdev
))) {
1736 sdev_printk(KERN_ERR
, sdev
,
1737 "rejecting I/O to offline device\n");
1738 scsi_kill_request(req
, q
);
1742 if (!scsi_dev_queue_ready(q
, sdev
))
1746 * Remove the request from the request list.
1748 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1749 blk_start_request(req
);
1751 spin_unlock_irq(q
->queue_lock
);
1753 if (unlikely(cmd
== NULL
)) {
1754 printk(KERN_CRIT
"impossible request in %s.\n"
1755 "please mail a stack trace to "
1756 "linux-scsi@vger.kernel.org\n",
1758 blk_dump_rq_flags(req
, "foo");
1763 * We hit this when the driver is using a host wide
1764 * tag map. For device level tag maps the queue_depth check
1765 * in the device ready fn would prevent us from trying
1766 * to allocate a tag. Since the map is a shared host resource
1767 * we add the dev to the starved list so it eventually gets
1768 * a run when a tag is freed.
1770 if (blk_queue_tagged(q
) && !(req
->rq_flags
& RQF_QUEUED
)) {
1771 spin_lock_irq(shost
->host_lock
);
1772 if (list_empty(&sdev
->starved_entry
))
1773 list_add_tail(&sdev
->starved_entry
,
1774 &shost
->starved_list
);
1775 spin_unlock_irq(shost
->host_lock
);
1779 if (!scsi_target_queue_ready(shost
, sdev
))
1782 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1783 goto host_not_ready
;
1785 if (sdev
->simple_tags
)
1786 cmd
->flags
|= SCMD_TAGGED
;
1788 cmd
->flags
&= ~SCMD_TAGGED
;
1791 * Finally, initialize any error handling parameters, and set up
1792 * the timers for timeouts.
1794 scsi_init_cmd_errh(cmd
);
1797 * Dispatch the command to the low-level driver.
1799 cmd
->scsi_done
= scsi_done
;
1800 rtn
= scsi_dispatch_cmd(cmd
);
1802 scsi_queue_insert(cmd
, rtn
);
1803 spin_lock_irq(q
->queue_lock
);
1806 spin_lock_irq(q
->queue_lock
);
1812 if (scsi_target(sdev
)->can_queue
> 0)
1813 atomic_dec(&scsi_target(sdev
)->target_busy
);
1816 * lock q, handle tag, requeue req, and decrement device_busy. We
1817 * must return with queue_lock held.
1819 * Decrementing device_busy without checking it is OK, as all such
1820 * cases (host limits or settings) should run the queue at some
1823 spin_lock_irq(q
->queue_lock
);
1824 blk_requeue_request(q
, req
);
1825 atomic_dec(&sdev
->device_busy
);
1827 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1828 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1831 static inline int prep_to_mq(int ret
)
1835 return BLK_MQ_RQ_QUEUE_OK
;
1837 return BLK_MQ_RQ_QUEUE_BUSY
;
1839 return BLK_MQ_RQ_QUEUE_ERROR
;
1843 static int scsi_mq_prep_fn(struct request
*req
)
1845 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1846 struct scsi_device
*sdev
= req
->q
->queuedata
;
1847 struct Scsi_Host
*shost
= sdev
->host
;
1848 unsigned char *sense_buf
= cmd
->sense_buffer
;
1849 struct scatterlist
*sg
;
1851 /* zero out the cmd, except for the embedded scsi_request */
1852 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1853 sizeof(*cmd
) - sizeof(cmd
->req
));
1859 cmd
->sense_buffer
= sense_buf
;
1861 cmd
->tag
= req
->tag
;
1863 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1865 INIT_LIST_HEAD(&cmd
->list
);
1866 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1867 cmd
->jiffies_at_alloc
= jiffies
;
1869 if (shost
->use_cmd_list
) {
1870 spin_lock_irq(&sdev
->list_lock
);
1871 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1872 spin_unlock_irq(&sdev
->list_lock
);
1875 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1876 cmd
->sdb
.table
.sgl
= sg
;
1878 if (scsi_host_get_prot(shost
)) {
1879 cmd
->prot_sdb
= (void *)sg
+
1881 shost
->sg_tablesize
, SG_CHUNK_SIZE
) *
1882 sizeof(struct scatterlist
);
1883 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1885 cmd
->prot_sdb
->table
.sgl
=
1886 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1889 if (blk_bidi_rq(req
)) {
1890 struct request
*next_rq
= req
->next_rq
;
1891 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1893 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1894 bidi_sdb
->table
.sgl
=
1895 (struct scatterlist
*)(bidi_sdb
+ 1);
1897 next_rq
->special
= bidi_sdb
;
1900 blk_mq_start_request(req
);
1902 return scsi_setup_cmnd(sdev
, req
);
1905 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1907 trace_scsi_dispatch_cmd_done(cmd
);
1908 blk_mq_complete_request(cmd
->request
, cmd
->request
->errors
);
1911 static int scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1912 const struct blk_mq_queue_data
*bd
)
1914 struct request
*req
= bd
->rq
;
1915 struct request_queue
*q
= req
->q
;
1916 struct scsi_device
*sdev
= q
->queuedata
;
1917 struct Scsi_Host
*shost
= sdev
->host
;
1918 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1922 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1923 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1926 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1927 if (!get_device(&sdev
->sdev_gendev
))
1930 if (!scsi_dev_queue_ready(q
, sdev
))
1931 goto out_put_device
;
1932 if (!scsi_target_queue_ready(shost
, sdev
))
1933 goto out_dec_device_busy
;
1934 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1935 goto out_dec_target_busy
;
1937 if (!(req
->rq_flags
& RQF_DONTPREP
)) {
1938 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1939 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1940 goto out_dec_host_busy
;
1941 req
->rq_flags
|= RQF_DONTPREP
;
1943 blk_mq_start_request(req
);
1946 if (sdev
->simple_tags
)
1947 cmd
->flags
|= SCMD_TAGGED
;
1949 cmd
->flags
&= ~SCMD_TAGGED
;
1951 scsi_init_cmd_errh(cmd
);
1952 cmd
->scsi_done
= scsi_mq_done
;
1954 reason
= scsi_dispatch_cmd(cmd
);
1956 scsi_set_blocked(cmd
, reason
);
1957 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1958 goto out_dec_host_busy
;
1961 return BLK_MQ_RQ_QUEUE_OK
;
1964 atomic_dec(&shost
->host_busy
);
1965 out_dec_target_busy
:
1966 if (scsi_target(sdev
)->can_queue
> 0)
1967 atomic_dec(&scsi_target(sdev
)->target_busy
);
1968 out_dec_device_busy
:
1969 atomic_dec(&sdev
->device_busy
);
1971 put_device(&sdev
->sdev_gendev
);
1974 case BLK_MQ_RQ_QUEUE_BUSY
:
1975 if (atomic_read(&sdev
->device_busy
) == 0 &&
1976 !scsi_device_blocked(sdev
))
1977 blk_mq_delay_queue(hctx
, SCSI_QUEUE_DELAY
);
1979 case BLK_MQ_RQ_QUEUE_ERROR
:
1981 * Make sure to release all allocated ressources when
1982 * we hit an error, as we will never see this command
1985 if (req
->rq_flags
& RQF_DONTPREP
)
1986 scsi_mq_uninit_cmd(cmd
);
1994 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
1998 return BLK_EH_RESET_TIMER
;
1999 return scsi_times_out(req
);
2002 static int scsi_init_request(void *data
, struct request
*rq
,
2003 unsigned int hctx_idx
, unsigned int request_idx
,
2004 unsigned int numa_node
)
2006 struct Scsi_Host
*shost
= data
;
2007 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2010 scsi_alloc_sense_buffer(shost
, GFP_KERNEL
, numa_node
);
2011 if (!cmd
->sense_buffer
)
2013 cmd
->req
.sense
= cmd
->sense_buffer
;
2017 static void scsi_exit_request(void *data
, struct request
*rq
,
2018 unsigned int hctx_idx
, unsigned int request_idx
)
2020 struct Scsi_Host
*shost
= data
;
2021 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2023 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2026 static int scsi_map_queues(struct blk_mq_tag_set
*set
)
2028 struct Scsi_Host
*shost
= container_of(set
, struct Scsi_Host
, tag_set
);
2030 if (shost
->hostt
->map_queues
)
2031 return shost
->hostt
->map_queues(shost
);
2032 return blk_mq_map_queues(set
);
2035 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2037 struct device
*host_dev
;
2038 u64 bounce_limit
= 0xffffffff;
2040 if (shost
->unchecked_isa_dma
)
2041 return BLK_BOUNCE_ISA
;
2043 * Platforms with virtual-DMA translation
2044 * hardware have no practical limit.
2046 if (!PCI_DMA_BUS_IS_PHYS
)
2047 return BLK_BOUNCE_ANY
;
2049 host_dev
= scsi_get_device(shost
);
2050 if (host_dev
&& host_dev
->dma_mask
)
2051 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2053 return bounce_limit
;
2056 void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2058 struct device
*dev
= shost
->dma_dev
;
2061 * this limit is imposed by hardware restrictions
2063 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
2066 if (scsi_host_prot_dma(shost
)) {
2067 shost
->sg_prot_tablesize
=
2068 min_not_zero(shost
->sg_prot_tablesize
,
2069 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
2070 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
2071 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
2074 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
2075 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
2076 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
2077 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
2079 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2081 if (!shost
->use_clustering
)
2082 q
->limits
.cluster
= 0;
2085 * set a reasonable default alignment on word boundaries: the
2086 * host and device may alter it using
2087 * blk_queue_update_dma_alignment() later.
2089 blk_queue_dma_alignment(q
, 0x03);
2091 EXPORT_SYMBOL_GPL(__scsi_init_queue
);
2093 static int scsi_init_rq(struct request_queue
*q
, struct request
*rq
, gfp_t gfp
)
2095 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2096 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2098 memset(cmd
, 0, sizeof(*cmd
));
2100 cmd
->sense_buffer
= scsi_alloc_sense_buffer(shost
, gfp
, NUMA_NO_NODE
);
2101 if (!cmd
->sense_buffer
)
2103 cmd
->req
.sense
= cmd
->sense_buffer
;
2105 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
2106 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp
);
2108 goto fail_free_sense
;
2114 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2119 static void scsi_exit_rq(struct request_queue
*q
, struct request
*rq
)
2121 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2122 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2125 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
2126 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2129 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
2131 struct Scsi_Host
*shost
= sdev
->host
;
2132 struct request_queue
*q
;
2134 q
= blk_alloc_queue_node(GFP_KERNEL
, NUMA_NO_NODE
);
2137 q
->cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
2138 q
->rq_alloc_data
= shost
;
2139 q
->request_fn
= scsi_request_fn
;
2140 q
->init_rq_fn
= scsi_init_rq
;
2141 q
->exit_rq_fn
= scsi_exit_rq
;
2143 if (blk_init_allocated_queue(q
) < 0) {
2144 blk_cleanup_queue(q
);
2148 __scsi_init_queue(shost
, q
);
2149 blk_queue_prep_rq(q
, scsi_prep_fn
);
2150 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2151 blk_queue_softirq_done(q
, scsi_softirq_done
);
2152 blk_queue_rq_timed_out(q
, scsi_times_out
);
2153 blk_queue_lld_busy(q
, scsi_lld_busy
);
2157 static struct blk_mq_ops scsi_mq_ops
= {
2158 .queue_rq
= scsi_queue_rq
,
2159 .complete
= scsi_softirq_done
,
2160 .timeout
= scsi_timeout
,
2161 .init_request
= scsi_init_request
,
2162 .exit_request
= scsi_exit_request
,
2163 .map_queues
= scsi_map_queues
,
2166 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2168 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2169 if (IS_ERR(sdev
->request_queue
))
2172 sdev
->request_queue
->queuedata
= sdev
;
2173 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2174 return sdev
->request_queue
;
2177 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2179 unsigned int cmd_size
, sgl_size
, tbl_size
;
2181 tbl_size
= shost
->sg_tablesize
;
2182 if (tbl_size
> SG_CHUNK_SIZE
)
2183 tbl_size
= SG_CHUNK_SIZE
;
2184 sgl_size
= tbl_size
* sizeof(struct scatterlist
);
2185 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2186 if (scsi_host_get_prot(shost
))
2187 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2189 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2190 shost
->tag_set
.ops
= &scsi_mq_ops
;
2191 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2192 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2193 shost
->tag_set
.cmd_size
= cmd_size
;
2194 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2195 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2196 shost
->tag_set
.flags
|=
2197 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2198 shost
->tag_set
.driver_data
= shost
;
2200 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2203 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2205 blk_mq_free_tag_set(&shost
->tag_set
);
2209 * scsi_device_from_queue - return sdev associated with a request_queue
2210 * @q: The request queue to return the sdev from
2212 * Return the sdev associated with a request queue or NULL if the
2213 * request_queue does not reference a SCSI device.
2215 struct scsi_device
*scsi_device_from_queue(struct request_queue
*q
)
2217 struct scsi_device
*sdev
= NULL
;
2220 if (q
->mq_ops
== &scsi_mq_ops
)
2221 sdev
= q
->queuedata
;
2222 } else if (q
->request_fn
== scsi_request_fn
)
2223 sdev
= q
->queuedata
;
2224 if (!sdev
|| !get_device(&sdev
->sdev_gendev
))
2229 EXPORT_SYMBOL_GPL(scsi_device_from_queue
);
2232 * Function: scsi_block_requests()
2234 * Purpose: Utility function used by low-level drivers to prevent further
2235 * commands from being queued to the device.
2237 * Arguments: shost - Host in question
2241 * Lock status: No locks are assumed held.
2243 * Notes: There is no timer nor any other means by which the requests
2244 * get unblocked other than the low-level driver calling
2245 * scsi_unblock_requests().
2247 void scsi_block_requests(struct Scsi_Host
*shost
)
2249 shost
->host_self_blocked
= 1;
2251 EXPORT_SYMBOL(scsi_block_requests
);
2254 * Function: scsi_unblock_requests()
2256 * Purpose: Utility function used by low-level drivers to allow further
2257 * commands from being queued to the device.
2259 * Arguments: shost - Host in question
2263 * Lock status: No locks are assumed held.
2265 * Notes: There is no timer nor any other means by which the requests
2266 * get unblocked other than the low-level driver calling
2267 * scsi_unblock_requests().
2269 * This is done as an API function so that changes to the
2270 * internals of the scsi mid-layer won't require wholesale
2271 * changes to drivers that use this feature.
2273 void scsi_unblock_requests(struct Scsi_Host
*shost
)
2275 shost
->host_self_blocked
= 0;
2276 scsi_run_host_queues(shost
);
2278 EXPORT_SYMBOL(scsi_unblock_requests
);
2280 int __init
scsi_init_queue(void)
2282 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
2283 sizeof(struct scsi_data_buffer
),
2285 if (!scsi_sdb_cache
) {
2286 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
2293 void scsi_exit_queue(void)
2295 kmem_cache_destroy(scsi_sense_cache
);
2296 kmem_cache_destroy(scsi_sense_isadma_cache
);
2297 kmem_cache_destroy(scsi_sdb_cache
);
2301 * scsi_mode_select - issue a mode select
2302 * @sdev: SCSI device to be queried
2303 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2304 * @sp: Save page bit (0 == don't save, 1 == save)
2305 * @modepage: mode page being requested
2306 * @buffer: request buffer (may not be smaller than eight bytes)
2307 * @len: length of request buffer.
2308 * @timeout: command timeout
2309 * @retries: number of retries before failing
2310 * @data: returns a structure abstracting the mode header data
2311 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2312 * must be SCSI_SENSE_BUFFERSIZE big.
2314 * Returns zero if successful; negative error number or scsi
2319 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
2320 unsigned char *buffer
, int len
, int timeout
, int retries
,
2321 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2323 unsigned char cmd
[10];
2324 unsigned char *real_buffer
;
2327 memset(cmd
, 0, sizeof(cmd
));
2328 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
2330 if (sdev
->use_10_for_ms
) {
2333 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
2336 memcpy(real_buffer
+ 8, buffer
, len
);
2340 real_buffer
[2] = data
->medium_type
;
2341 real_buffer
[3] = data
->device_specific
;
2342 real_buffer
[4] = data
->longlba
? 0x01 : 0;
2344 real_buffer
[6] = data
->block_descriptor_length
>> 8;
2345 real_buffer
[7] = data
->block_descriptor_length
;
2347 cmd
[0] = MODE_SELECT_10
;
2351 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2355 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2358 memcpy(real_buffer
+ 4, buffer
, len
);
2361 real_buffer
[1] = data
->medium_type
;
2362 real_buffer
[2] = data
->device_specific
;
2363 real_buffer
[3] = data
->block_descriptor_length
;
2366 cmd
[0] = MODE_SELECT
;
2370 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2371 sshdr
, timeout
, retries
, NULL
);
2375 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2378 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2379 * @sdev: SCSI device to be queried
2380 * @dbd: set if mode sense will allow block descriptors to be returned
2381 * @modepage: mode page being requested
2382 * @buffer: request buffer (may not be smaller than eight bytes)
2383 * @len: length of request buffer.
2384 * @timeout: command timeout
2385 * @retries: number of retries before failing
2386 * @data: returns a structure abstracting the mode header data
2387 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2388 * must be SCSI_SENSE_BUFFERSIZE big.
2390 * Returns zero if unsuccessful, or the header offset (either 4
2391 * or 8 depending on whether a six or ten byte command was
2392 * issued) if successful.
2395 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2396 unsigned char *buffer
, int len
, int timeout
, int retries
,
2397 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2399 unsigned char cmd
[12];
2402 int result
, retry_count
= retries
;
2403 struct scsi_sense_hdr my_sshdr
;
2405 memset(data
, 0, sizeof(*data
));
2406 memset(&cmd
[0], 0, 12);
2407 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2410 /* caller might not be interested in sense, but we need it */
2415 use_10_for_ms
= sdev
->use_10_for_ms
;
2417 if (use_10_for_ms
) {
2421 cmd
[0] = MODE_SENSE_10
;
2428 cmd
[0] = MODE_SENSE
;
2433 memset(buffer
, 0, len
);
2435 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2436 sshdr
, timeout
, retries
, NULL
);
2438 /* This code looks awful: what it's doing is making sure an
2439 * ILLEGAL REQUEST sense return identifies the actual command
2440 * byte as the problem. MODE_SENSE commands can return
2441 * ILLEGAL REQUEST if the code page isn't supported */
2443 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2444 (driver_byte(result
) & DRIVER_SENSE
)) {
2445 if (scsi_sense_valid(sshdr
)) {
2446 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2447 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2449 * Invalid command operation code
2451 sdev
->use_10_for_ms
= 0;
2457 if(scsi_status_is_good(result
)) {
2458 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2459 (modepage
== 6 || modepage
== 8))) {
2460 /* Initio breakage? */
2463 data
->medium_type
= 0;
2464 data
->device_specific
= 0;
2466 data
->block_descriptor_length
= 0;
2467 } else if(use_10_for_ms
) {
2468 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2469 data
->medium_type
= buffer
[2];
2470 data
->device_specific
= buffer
[3];
2471 data
->longlba
= buffer
[4] & 0x01;
2472 data
->block_descriptor_length
= buffer
[6]*256
2475 data
->length
= buffer
[0] + 1;
2476 data
->medium_type
= buffer
[1];
2477 data
->device_specific
= buffer
[2];
2478 data
->block_descriptor_length
= buffer
[3];
2480 data
->header_length
= header_length
;
2481 } else if ((status_byte(result
) == CHECK_CONDITION
) &&
2482 scsi_sense_valid(sshdr
) &&
2483 sshdr
->sense_key
== UNIT_ATTENTION
&& retry_count
) {
2490 EXPORT_SYMBOL(scsi_mode_sense
);
2493 * scsi_test_unit_ready - test if unit is ready
2494 * @sdev: scsi device to change the state of.
2495 * @timeout: command timeout
2496 * @retries: number of retries before failing
2497 * @sshdr: outpout pointer for decoded sense information.
2499 * Returns zero if unsuccessful or an error if TUR failed. For
2500 * removable media, UNIT_ATTENTION sets ->changed flag.
2503 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2504 struct scsi_sense_hdr
*sshdr
)
2507 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2511 /* try to eat the UNIT_ATTENTION if there are enough retries */
2513 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2514 timeout
, retries
, NULL
);
2515 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2516 sshdr
->sense_key
== UNIT_ATTENTION
)
2518 } while (scsi_sense_valid(sshdr
) &&
2519 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2523 EXPORT_SYMBOL(scsi_test_unit_ready
);
2526 * scsi_device_set_state - Take the given device through the device state model.
2527 * @sdev: scsi device to change the state of.
2528 * @state: state to change to.
2530 * Returns zero if unsuccessful or an error if the requested
2531 * transition is illegal.
2534 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2536 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2538 if (state
== oldstate
)
2544 case SDEV_CREATED_BLOCK
:
2555 case SDEV_TRANSPORT_OFFLINE
:
2568 case SDEV_TRANSPORT_OFFLINE
:
2576 case SDEV_TRANSPORT_OFFLINE
:
2591 case SDEV_CREATED_BLOCK
:
2598 case SDEV_CREATED_BLOCK
:
2613 case SDEV_TRANSPORT_OFFLINE
:
2626 case SDEV_TRANSPORT_OFFLINE
:
2628 case SDEV_CREATED_BLOCK
:
2636 sdev
->sdev_state
= state
;
2640 SCSI_LOG_ERROR_RECOVERY(1,
2641 sdev_printk(KERN_ERR
, sdev
,
2642 "Illegal state transition %s->%s",
2643 scsi_device_state_name(oldstate
),
2644 scsi_device_state_name(state
))
2648 EXPORT_SYMBOL(scsi_device_set_state
);
2651 * sdev_evt_emit - emit a single SCSI device uevent
2652 * @sdev: associated SCSI device
2653 * @evt: event to emit
2655 * Send a single uevent (scsi_event) to the associated scsi_device.
2657 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2662 switch (evt
->evt_type
) {
2663 case SDEV_EVT_MEDIA_CHANGE
:
2664 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2666 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2667 scsi_rescan_device(&sdev
->sdev_gendev
);
2668 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2670 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2671 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2673 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2674 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2676 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2677 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2679 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2680 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2682 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2683 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2692 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2696 * sdev_evt_thread - send a uevent for each scsi event
2697 * @work: work struct for scsi_device
2699 * Dispatch queued events to their associated scsi_device kobjects
2702 void scsi_evt_thread(struct work_struct
*work
)
2704 struct scsi_device
*sdev
;
2705 enum scsi_device_event evt_type
;
2706 LIST_HEAD(event_list
);
2708 sdev
= container_of(work
, struct scsi_device
, event_work
);
2710 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2711 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2712 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2715 struct scsi_event
*evt
;
2716 struct list_head
*this, *tmp
;
2717 unsigned long flags
;
2719 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2720 list_splice_init(&sdev
->event_list
, &event_list
);
2721 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2723 if (list_empty(&event_list
))
2726 list_for_each_safe(this, tmp
, &event_list
) {
2727 evt
= list_entry(this, struct scsi_event
, node
);
2728 list_del(&evt
->node
);
2729 scsi_evt_emit(sdev
, evt
);
2736 * sdev_evt_send - send asserted event to uevent thread
2737 * @sdev: scsi_device event occurred on
2738 * @evt: event to send
2740 * Assert scsi device event asynchronously.
2742 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2744 unsigned long flags
;
2747 /* FIXME: currently this check eliminates all media change events
2748 * for polled devices. Need to update to discriminate between AN
2749 * and polled events */
2750 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2756 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2757 list_add_tail(&evt
->node
, &sdev
->event_list
);
2758 schedule_work(&sdev
->event_work
);
2759 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2761 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2764 * sdev_evt_alloc - allocate a new scsi event
2765 * @evt_type: type of event to allocate
2766 * @gfpflags: GFP flags for allocation
2768 * Allocates and returns a new scsi_event.
2770 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2773 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2777 evt
->evt_type
= evt_type
;
2778 INIT_LIST_HEAD(&evt
->node
);
2780 /* evt_type-specific initialization, if any */
2782 case SDEV_EVT_MEDIA_CHANGE
:
2783 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2784 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2785 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2786 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2787 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2788 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2796 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2799 * sdev_evt_send_simple - send asserted event to uevent thread
2800 * @sdev: scsi_device event occurred on
2801 * @evt_type: type of event to send
2802 * @gfpflags: GFP flags for allocation
2804 * Assert scsi device event asynchronously, given an event type.
2806 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2807 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2809 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2811 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2816 sdev_evt_send(sdev
, evt
);
2818 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2821 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2822 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2824 static int scsi_request_fn_active(struct scsi_device
*sdev
)
2826 struct request_queue
*q
= sdev
->request_queue
;
2827 int request_fn_active
;
2829 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2831 spin_lock_irq(q
->queue_lock
);
2832 request_fn_active
= q
->request_fn_active
;
2833 spin_unlock_irq(q
->queue_lock
);
2835 return request_fn_active
;
2839 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2840 * @sdev: SCSI device pointer.
2842 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2843 * invoked from scsi_request_fn() have finished.
2845 static void scsi_wait_for_queuecommand(struct scsi_device
*sdev
)
2847 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2849 while (scsi_request_fn_active(sdev
))
2854 * scsi_device_quiesce - Block user issued commands.
2855 * @sdev: scsi device to quiesce.
2857 * This works by trying to transition to the SDEV_QUIESCE state
2858 * (which must be a legal transition). When the device is in this
2859 * state, only special requests will be accepted, all others will
2860 * be deferred. Since special requests may also be requeued requests,
2861 * a successful return doesn't guarantee the device will be
2862 * totally quiescent.
2864 * Must be called with user context, may sleep.
2866 * Returns zero if unsuccessful or an error if not.
2869 scsi_device_quiesce(struct scsi_device
*sdev
)
2871 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2875 scsi_run_queue(sdev
->request_queue
);
2876 while (atomic_read(&sdev
->device_busy
)) {
2877 msleep_interruptible(200);
2878 scsi_run_queue(sdev
->request_queue
);
2882 EXPORT_SYMBOL(scsi_device_quiesce
);
2885 * scsi_device_resume - Restart user issued commands to a quiesced device.
2886 * @sdev: scsi device to resume.
2888 * Moves the device from quiesced back to running and restarts the
2891 * Must be called with user context, may sleep.
2893 void scsi_device_resume(struct scsi_device
*sdev
)
2895 /* check if the device state was mutated prior to resume, and if
2896 * so assume the state is being managed elsewhere (for example
2897 * device deleted during suspend)
2899 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2900 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2902 scsi_run_queue(sdev
->request_queue
);
2904 EXPORT_SYMBOL(scsi_device_resume
);
2907 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2909 scsi_device_quiesce(sdev
);
2913 scsi_target_quiesce(struct scsi_target
*starget
)
2915 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2917 EXPORT_SYMBOL(scsi_target_quiesce
);
2920 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2922 scsi_device_resume(sdev
);
2926 scsi_target_resume(struct scsi_target
*starget
)
2928 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2930 EXPORT_SYMBOL(scsi_target_resume
);
2933 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2934 * @sdev: device to block
2936 * Block request made by scsi lld's to temporarily stop all
2937 * scsi commands on the specified device. May sleep.
2939 * Returns zero if successful or error if not
2942 * This routine transitions the device to the SDEV_BLOCK state
2943 * (which must be a legal transition). When the device is in this
2944 * state, all commands are deferred until the scsi lld reenables
2945 * the device with scsi_device_unblock or device_block_tmo fires.
2947 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2948 * scsi_internal_device_block() has blocked a SCSI device and also
2949 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2952 scsi_internal_device_block(struct scsi_device
*sdev
)
2954 struct request_queue
*q
= sdev
->request_queue
;
2955 unsigned long flags
;
2958 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2960 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2967 * The device has transitioned to SDEV_BLOCK. Stop the
2968 * block layer from calling the midlayer with this device's
2972 blk_mq_quiesce_queue(q
);
2974 spin_lock_irqsave(q
->queue_lock
, flags
);
2976 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2977 scsi_wait_for_queuecommand(sdev
);
2982 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2985 * scsi_internal_device_unblock - resume a device after a block request
2986 * @sdev: device to resume
2987 * @new_state: state to set devices to after unblocking
2989 * Called by scsi lld's or the midlayer to restart the device queue
2990 * for the previously suspended scsi device. Called from interrupt or
2991 * normal process context.
2993 * Returns zero if successful or error if not.
2996 * This routine transitions the device to the SDEV_RUNNING state
2997 * or to one of the offline states (which must be a legal transition)
2998 * allowing the midlayer to goose the queue for this device.
3001 scsi_internal_device_unblock(struct scsi_device
*sdev
,
3002 enum scsi_device_state new_state
)
3004 struct request_queue
*q
= sdev
->request_queue
;
3005 unsigned long flags
;
3008 * Try to transition the scsi device to SDEV_RUNNING or one of the
3009 * offlined states and goose the device queue if successful.
3011 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
3012 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
3013 sdev
->sdev_state
= new_state
;
3014 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
3015 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3016 new_state
== SDEV_OFFLINE
)
3017 sdev
->sdev_state
= new_state
;
3019 sdev
->sdev_state
= SDEV_CREATED
;
3020 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
3021 sdev
->sdev_state
!= SDEV_OFFLINE
)
3025 blk_mq_start_stopped_hw_queues(q
, false);
3027 spin_lock_irqsave(q
->queue_lock
, flags
);
3029 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3034 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
3037 device_block(struct scsi_device
*sdev
, void *data
)
3039 scsi_internal_device_block(sdev
);
3043 target_block(struct device
*dev
, void *data
)
3045 if (scsi_is_target_device(dev
))
3046 starget_for_each_device(to_scsi_target(dev
), NULL
,
3052 scsi_target_block(struct device
*dev
)
3054 if (scsi_is_target_device(dev
))
3055 starget_for_each_device(to_scsi_target(dev
), NULL
,
3058 device_for_each_child(dev
, NULL
, target_block
);
3060 EXPORT_SYMBOL_GPL(scsi_target_block
);
3063 device_unblock(struct scsi_device
*sdev
, void *data
)
3065 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3069 target_unblock(struct device
*dev
, void *data
)
3071 if (scsi_is_target_device(dev
))
3072 starget_for_each_device(to_scsi_target(dev
), data
,
3078 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3080 if (scsi_is_target_device(dev
))
3081 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3084 device_for_each_child(dev
, &new_state
, target_unblock
);
3086 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3089 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3090 * @sgl: scatter-gather list
3091 * @sg_count: number of segments in sg
3092 * @offset: offset in bytes into sg, on return offset into the mapped area
3093 * @len: bytes to map, on return number of bytes mapped
3095 * Returns virtual address of the start of the mapped page
3097 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3098 size_t *offset
, size_t *len
)
3101 size_t sg_len
= 0, len_complete
= 0;
3102 struct scatterlist
*sg
;
3105 WARN_ON(!irqs_disabled());
3107 for_each_sg(sgl
, sg
, sg_count
, i
) {
3108 len_complete
= sg_len
; /* Complete sg-entries */
3109 sg_len
+= sg
->length
;
3110 if (sg_len
> *offset
)
3114 if (unlikely(i
== sg_count
)) {
3115 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3117 __func__
, sg_len
, *offset
, sg_count
);
3122 /* Offset starting from the beginning of first page in this sg-entry */
3123 *offset
= *offset
- len_complete
+ sg
->offset
;
3125 /* Assumption: contiguous pages can be accessed as "page + i" */
3126 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3127 *offset
&= ~PAGE_MASK
;
3129 /* Bytes in this sg-entry from *offset to the end of the page */
3130 sg_len
= PAGE_SIZE
- *offset
;
3134 return kmap_atomic(page
);
3136 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3139 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3140 * @virt: virtual address to be unmapped
3142 void scsi_kunmap_atomic_sg(void *virt
)
3144 kunmap_atomic(virt
);
3146 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3148 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3150 atomic_inc(&sdev
->disk_events_disable_depth
);
3152 EXPORT_SYMBOL(sdev_disable_disk_events
);
3154 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3156 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3158 atomic_dec(&sdev
->disk_events_disable_depth
);
3160 EXPORT_SYMBOL(sdev_enable_disk_events
);
3163 * scsi_vpd_lun_id - return a unique device identification
3164 * @sdev: SCSI device
3165 * @id: buffer for the identification
3166 * @id_len: length of the buffer
3168 * Copies a unique device identification into @id based
3169 * on the information in the VPD page 0x83 of the device.
3170 * The string will be formatted as a SCSI name string.
3172 * Returns the length of the identification or error on failure.
3173 * If the identifier is longer than the supplied buffer the actual
3174 * identifier length is returned and the buffer is not zero-padded.
3176 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3178 u8 cur_id_type
= 0xff;
3180 unsigned char *d
, *cur_id_str
;
3181 unsigned char __rcu
*vpd_pg83
;
3182 int id_size
= -EINVAL
;
3185 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3192 * Look for the correct descriptor.
3193 * Order of preference for lun descriptor:
3194 * - SCSI name string
3195 * - NAA IEEE Registered Extended
3196 * - EUI-64 based 16-byte
3197 * - EUI-64 based 12-byte
3198 * - NAA IEEE Registered
3199 * - NAA IEEE Extended
3201 * as longer descriptors reduce the likelyhood
3202 * of identification clashes.
3205 /* The id string must be at least 20 bytes + terminating NULL byte */
3211 memset(id
, 0, id_len
);
3213 while (d
< vpd_pg83
+ sdev
->vpd_pg83_len
) {
3214 /* Skip designators not referring to the LUN */
3215 if ((d
[1] & 0x30) != 0x00)
3218 switch (d
[1] & 0xf) {
3221 if (cur_id_size
> d
[3])
3223 /* Prefer anything */
3224 if (cur_id_type
> 0x01 && cur_id_type
!= 0xff)
3227 if (cur_id_size
+ 4 > id_len
)
3228 cur_id_size
= id_len
- 4;
3230 cur_id_type
= d
[1] & 0xf;
3231 id_size
= snprintf(id
, id_len
, "t10.%*pE",
3232 cur_id_size
, cur_id_str
);
3236 if (cur_id_size
> d
[3])
3238 /* Prefer NAA IEEE Registered Extended */
3239 if (cur_id_type
== 0x3 &&
3240 cur_id_size
== d
[3])
3244 cur_id_type
= d
[1] & 0xf;
3245 switch (cur_id_size
) {
3247 id_size
= snprintf(id
, id_len
,
3252 id_size
= snprintf(id
, id_len
,
3257 id_size
= snprintf(id
, id_len
,
3268 if (cur_id_size
> d
[3])
3272 cur_id_type
= d
[1] & 0xf;
3273 switch (cur_id_size
) {
3275 id_size
= snprintf(id
, id_len
,
3280 id_size
= snprintf(id
, id_len
,
3290 /* SCSI name string */
3291 if (cur_id_size
+ 4 > d
[3])
3293 /* Prefer others for truncated descriptor */
3294 if (cur_id_size
&& d
[3] > id_len
)
3296 cur_id_size
= id_size
= d
[3];
3298 cur_id_type
= d
[1] & 0xf;
3299 if (cur_id_size
>= id_len
)
3300 cur_id_size
= id_len
- 1;
3301 memcpy(id
, cur_id_str
, cur_id_size
);
3302 /* Decrease priority for truncated descriptor */
3303 if (cur_id_size
!= id_size
)
3316 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3319 * scsi_vpd_tpg_id - return a target port group identifier
3320 * @sdev: SCSI device
3322 * Returns the Target Port Group identifier from the information
3323 * froom VPD page 0x83 of the device.
3325 * Returns the identifier or error on failure.
3327 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3330 unsigned char __rcu
*vpd_pg83
;
3331 int group_id
= -EAGAIN
, rel_port
= -1;
3334 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3340 d
= sdev
->vpd_pg83
+ 4;
3341 while (d
< sdev
->vpd_pg83
+ sdev
->vpd_pg83_len
) {
3342 switch (d
[1] & 0xf) {
3344 /* Relative target port */
3345 rel_port
= get_unaligned_be16(&d
[6]);
3348 /* Target port group */
3349 group_id
= get_unaligned_be16(&d
[6]);
3358 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3363 EXPORT_SYMBOL(scsi_vpd_tpg_id
);