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);
216 static int __scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
217 int data_direction
, void *buffer
, unsigned bufflen
,
218 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
219 req_flags_t rq_flags
, int *resid
)
222 int write
= (data_direction
== DMA_TO_DEVICE
);
223 struct scsi_request
*rq
;
224 int ret
= DRIVER_ERROR
<< 24;
226 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_RECLAIM
);
232 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
233 buffer
, bufflen
, __GFP_RECLAIM
))
236 rq
->cmd_len
= COMMAND_SIZE(cmd
[0]);
237 memcpy(rq
->cmd
, cmd
, rq
->cmd_len
);
238 req
->retries
= retries
;
239 req
->timeout
= timeout
;
240 req
->cmd_flags
|= flags
;
241 req
->rq_flags
|= rq_flags
| RQF_QUIET
| RQF_PREEMPT
;
244 * head injection *required* here otherwise quiesce won't work
246 blk_execute_rq(req
->q
, NULL
, req
, 1);
249 * Some devices (USB mass-storage in particular) may transfer
250 * garbage data together with a residue indicating that the data
251 * is invalid. Prevent the garbage from being misinterpreted
252 * and prevent security leaks by zeroing out the excess data.
254 if (unlikely(rq
->resid_len
> 0 && rq
->resid_len
<= bufflen
))
255 memset(buffer
+ (bufflen
- rq
->resid_len
), 0, rq
->resid_len
);
258 *resid
= rq
->resid_len
;
259 if (sense
&& rq
->sense_len
)
260 memcpy(sense
, rq
->sense
, SCSI_SENSE_BUFFERSIZE
);
263 blk_put_request(req
);
269 * scsi_execute - insert request and wait for the result
272 * @data_direction: data direction
273 * @buffer: data buffer
274 * @bufflen: len of buffer
275 * @sense: optional sense buffer
276 * @timeout: request timeout in seconds
277 * @retries: number of times to retry request
278 * @flags: or into request flags;
279 * @resid: optional residual length
281 * returns the req->errors value which is the scsi_cmnd result
284 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
285 int data_direction
, void *buffer
, unsigned bufflen
,
286 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
289 return __scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
, sense
,
290 timeout
, retries
, flags
, 0, resid
);
292 EXPORT_SYMBOL(scsi_execute
);
294 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
295 int data_direction
, void *buffer
, unsigned bufflen
,
296 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
297 int *resid
, u64 flags
, req_flags_t rq_flags
)
303 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
305 return DRIVER_ERROR
<< 24;
307 result
= __scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
308 sense
, timeout
, retries
, flags
, rq_flags
, resid
);
310 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
315 EXPORT_SYMBOL(scsi_execute_req_flags
);
318 * Function: scsi_init_cmd_errh()
320 * Purpose: Initialize cmd fields related to error handling.
322 * Arguments: cmd - command that is ready to be queued.
324 * Notes: This function has the job of initializing a number of
325 * fields related to error handling. Typically this will
326 * be called once for each command, as required.
328 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
330 cmd
->serial_number
= 0;
331 scsi_set_resid(cmd
, 0);
332 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
333 if (cmd
->cmd_len
== 0)
334 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
337 void scsi_device_unbusy(struct scsi_device
*sdev
)
339 struct Scsi_Host
*shost
= sdev
->host
;
340 struct scsi_target
*starget
= scsi_target(sdev
);
343 atomic_dec(&shost
->host_busy
);
344 if (starget
->can_queue
> 0)
345 atomic_dec(&starget
->target_busy
);
347 if (unlikely(scsi_host_in_recovery(shost
) &&
348 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
349 spin_lock_irqsave(shost
->host_lock
, flags
);
350 scsi_eh_wakeup(shost
);
351 spin_unlock_irqrestore(shost
->host_lock
, flags
);
354 atomic_dec(&sdev
->device_busy
);
357 static void scsi_kick_queue(struct request_queue
*q
)
360 blk_mq_start_hw_queues(q
);
366 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
367 * and call blk_run_queue for all the scsi_devices on the target -
368 * including current_sdev first.
370 * Called with *no* scsi locks held.
372 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
374 struct Scsi_Host
*shost
= current_sdev
->host
;
375 struct scsi_device
*sdev
, *tmp
;
376 struct scsi_target
*starget
= scsi_target(current_sdev
);
379 spin_lock_irqsave(shost
->host_lock
, flags
);
380 starget
->starget_sdev_user
= NULL
;
381 spin_unlock_irqrestore(shost
->host_lock
, flags
);
384 * Call blk_run_queue for all LUNs on the target, starting with
385 * current_sdev. We race with others (to set starget_sdev_user),
386 * but in most cases, we will be first. Ideally, each LU on the
387 * target would get some limited time or requests on the target.
389 scsi_kick_queue(current_sdev
->request_queue
);
391 spin_lock_irqsave(shost
->host_lock
, flags
);
392 if (starget
->starget_sdev_user
)
394 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
395 same_target_siblings
) {
396 if (sdev
== current_sdev
)
398 if (scsi_device_get(sdev
))
401 spin_unlock_irqrestore(shost
->host_lock
, flags
);
402 scsi_kick_queue(sdev
->request_queue
);
403 spin_lock_irqsave(shost
->host_lock
, flags
);
405 scsi_device_put(sdev
);
408 spin_unlock_irqrestore(shost
->host_lock
, flags
);
411 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
413 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
415 if (atomic_read(&sdev
->device_blocked
) > 0)
420 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
422 if (starget
->can_queue
> 0) {
423 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
425 if (atomic_read(&starget
->target_blocked
) > 0)
431 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
433 if (shost
->can_queue
> 0 &&
434 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
436 if (atomic_read(&shost
->host_blocked
) > 0)
438 if (shost
->host_self_blocked
)
443 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
445 LIST_HEAD(starved_list
);
446 struct scsi_device
*sdev
;
449 spin_lock_irqsave(shost
->host_lock
, flags
);
450 list_splice_init(&shost
->starved_list
, &starved_list
);
452 while (!list_empty(&starved_list
)) {
453 struct request_queue
*slq
;
456 * As long as shost is accepting commands and we have
457 * starved queues, call blk_run_queue. scsi_request_fn
458 * drops the queue_lock and can add us back to the
461 * host_lock protects the starved_list and starved_entry.
462 * scsi_request_fn must get the host_lock before checking
463 * or modifying starved_list or starved_entry.
465 if (scsi_host_is_busy(shost
))
468 sdev
= list_entry(starved_list
.next
,
469 struct scsi_device
, starved_entry
);
470 list_del_init(&sdev
->starved_entry
);
471 if (scsi_target_is_busy(scsi_target(sdev
))) {
472 list_move_tail(&sdev
->starved_entry
,
473 &shost
->starved_list
);
478 * Once we drop the host lock, a racing scsi_remove_device()
479 * call may remove the sdev from the starved list and destroy
480 * it and the queue. Mitigate by taking a reference to the
481 * queue and never touching the sdev again after we drop the
482 * host lock. Note: if __scsi_remove_device() invokes
483 * blk_cleanup_queue() before the queue is run from this
484 * function then blk_run_queue() will return immediately since
485 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
487 slq
= sdev
->request_queue
;
488 if (!blk_get_queue(slq
))
490 spin_unlock_irqrestore(shost
->host_lock
, flags
);
492 scsi_kick_queue(slq
);
495 spin_lock_irqsave(shost
->host_lock
, flags
);
497 /* put any unprocessed entries back */
498 list_splice(&starved_list
, &shost
->starved_list
);
499 spin_unlock_irqrestore(shost
->host_lock
, flags
);
503 * Function: scsi_run_queue()
505 * Purpose: Select a proper request queue to serve next
507 * Arguments: q - last request's queue
511 * Notes: The previous command was completely finished, start
512 * a new one if possible.
514 static void scsi_run_queue(struct request_queue
*q
)
516 struct scsi_device
*sdev
= q
->queuedata
;
518 if (scsi_target(sdev
)->single_lun
)
519 scsi_single_lun_run(sdev
);
520 if (!list_empty(&sdev
->host
->starved_list
))
521 scsi_starved_list_run(sdev
->host
);
524 blk_mq_start_stopped_hw_queues(q
, false);
529 void scsi_requeue_run_queue(struct work_struct
*work
)
531 struct scsi_device
*sdev
;
532 struct request_queue
*q
;
534 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
535 q
= sdev
->request_queue
;
540 * Function: scsi_requeue_command()
542 * Purpose: Handle post-processing of completed commands.
544 * Arguments: q - queue to operate on
545 * cmd - command that may need to be requeued.
549 * Notes: After command completion, there may be blocks left
550 * over which weren't finished by the previous command
551 * this can be for a number of reasons - the main one is
552 * I/O errors in the middle of the request, in which case
553 * we need to request the blocks that come after the bad
555 * Notes: Upon return, cmd is a stale pointer.
557 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
559 struct scsi_device
*sdev
= cmd
->device
;
560 struct request
*req
= cmd
->request
;
563 spin_lock_irqsave(q
->queue_lock
, flags
);
564 blk_unprep_request(req
);
566 scsi_put_command(cmd
);
567 blk_requeue_request(q
, req
);
568 spin_unlock_irqrestore(q
->queue_lock
, flags
);
572 put_device(&sdev
->sdev_gendev
);
575 void scsi_run_host_queues(struct Scsi_Host
*shost
)
577 struct scsi_device
*sdev
;
579 shost_for_each_device(sdev
, shost
)
580 scsi_run_queue(sdev
->request_queue
);
583 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
585 if (!blk_rq_is_passthrough(cmd
->request
)) {
586 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
588 if (drv
->uninit_command
)
589 drv
->uninit_command(cmd
);
593 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
595 struct scsi_data_buffer
*sdb
;
597 if (cmd
->sdb
.table
.nents
)
598 sg_free_table_chained(&cmd
->sdb
.table
, true);
599 if (cmd
->request
->next_rq
) {
600 sdb
= cmd
->request
->next_rq
->special
;
602 sg_free_table_chained(&sdb
->table
, true);
604 if (scsi_prot_sg_count(cmd
))
605 sg_free_table_chained(&cmd
->prot_sdb
->table
, true);
608 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
610 struct scsi_device
*sdev
= cmd
->device
;
611 struct Scsi_Host
*shost
= sdev
->host
;
614 scsi_mq_free_sgtables(cmd
);
615 scsi_uninit_cmd(cmd
);
617 if (shost
->use_cmd_list
) {
618 BUG_ON(list_empty(&cmd
->list
));
619 spin_lock_irqsave(&sdev
->list_lock
, flags
);
620 list_del_init(&cmd
->list
);
621 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
626 * Function: scsi_release_buffers()
628 * Purpose: Free resources allocate for a scsi_command.
630 * Arguments: cmd - command that we are bailing.
632 * Lock status: Assumed that no lock is held upon entry.
636 * Notes: In the event that an upper level driver rejects a
637 * command, we must release resources allocated during
638 * the __init_io() function. Primarily this would involve
639 * the scatter-gather table.
641 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
643 if (cmd
->sdb
.table
.nents
)
644 sg_free_table_chained(&cmd
->sdb
.table
, false);
646 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
648 if (scsi_prot_sg_count(cmd
))
649 sg_free_table_chained(&cmd
->prot_sdb
->table
, false);
652 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
654 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
656 sg_free_table_chained(&bidi_sdb
->table
, false);
657 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
658 cmd
->request
->next_rq
->special
= NULL
;
661 static bool scsi_end_request(struct request
*req
, int error
,
662 unsigned int bytes
, unsigned int bidi_bytes
)
664 struct scsi_cmnd
*cmd
= req
->special
;
665 struct scsi_device
*sdev
= cmd
->device
;
666 struct request_queue
*q
= sdev
->request_queue
;
668 if (blk_update_request(req
, error
, bytes
))
671 /* Bidi request must be completed as a whole */
672 if (unlikely(bidi_bytes
) &&
673 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
676 if (blk_queue_add_random(q
))
677 add_disk_randomness(req
->rq_disk
);
681 * In the MQ case the command gets freed by __blk_mq_end_request,
682 * so we have to do all cleanup that depends on it earlier.
684 * We also can't kick the queues from irq context, so we
685 * will have to defer it to a workqueue.
687 scsi_mq_uninit_cmd(cmd
);
689 __blk_mq_end_request(req
, error
);
691 if (scsi_target(sdev
)->single_lun
||
692 !list_empty(&sdev
->host
->starved_list
))
693 kblockd_schedule_work(&sdev
->requeue_work
);
695 blk_mq_start_stopped_hw_queues(q
, true);
700 scsi_release_bidi_buffers(cmd
);
701 scsi_release_buffers(cmd
);
702 scsi_put_command(cmd
);
704 spin_lock_irqsave(q
->queue_lock
, flags
);
705 blk_finish_request(req
, error
);
706 spin_unlock_irqrestore(q
->queue_lock
, flags
);
711 put_device(&sdev
->sdev_gendev
);
716 * __scsi_error_from_host_byte - translate SCSI error code into errno
717 * @cmd: SCSI command (unused)
718 * @result: scsi error code
720 * Translate SCSI error code into standard UNIX errno.
722 * -ENOLINK temporary transport failure
723 * -EREMOTEIO permanent target failure, do not retry
724 * -EBADE permanent nexus failure, retry on other path
725 * -ENOSPC No write space available
726 * -ENODATA Medium error
727 * -EIO unspecified I/O error
729 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
733 switch(host_byte(result
)) {
734 case DID_TRANSPORT_FAILFAST
:
737 case DID_TARGET_FAILURE
:
738 set_host_byte(cmd
, DID_OK
);
741 case DID_NEXUS_FAILURE
:
742 set_host_byte(cmd
, DID_OK
);
745 case DID_ALLOC_FAILURE
:
746 set_host_byte(cmd
, DID_OK
);
749 case DID_MEDIUM_ERROR
:
750 set_host_byte(cmd
, DID_OK
);
762 * Function: scsi_io_completion()
764 * Purpose: Completion processing for block device I/O requests.
766 * Arguments: cmd - command that is finished.
768 * Lock status: Assumed that no lock is held upon entry.
772 * Notes: We will finish off the specified number of sectors. If we
773 * are done, the command block will be released and the queue
774 * function will be goosed. If we are not done then we have to
775 * figure out what to do next:
777 * a) We can call scsi_requeue_command(). The request
778 * will be unprepared and put back on the queue. Then
779 * a new command will be created for it. This should
780 * be used if we made forward progress, or if we want
781 * to switch from READ(10) to READ(6) for example.
783 * b) We can call __scsi_queue_insert(). The request will
784 * be put back on the queue and retried using the same
785 * command as before, possibly after a delay.
787 * c) We can call scsi_end_request() with -EIO to fail
788 * the remainder of the request.
790 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
792 int result
= cmd
->result
;
793 struct request_queue
*q
= cmd
->device
->request_queue
;
794 struct request
*req
= cmd
->request
;
796 struct scsi_sense_hdr sshdr
;
797 bool sense_valid
= false;
798 int sense_deferred
= 0, level
= 0;
799 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
800 ACTION_DELAYED_RETRY
} action
;
801 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
804 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
806 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
809 if (blk_rq_is_passthrough(req
)) {
813 * SG_IO wants current and deferred errors
815 scsi_req(req
)->sense_len
=
816 min(8 + cmd
->sense_buffer
[7],
817 SCSI_SENSE_BUFFERSIZE
);
820 error
= __scsi_error_from_host_byte(cmd
, result
);
823 * __scsi_error_from_host_byte may have reset the host_byte
825 req
->errors
= cmd
->result
;
827 scsi_req(req
)->resid_len
= scsi_get_resid(cmd
);
829 if (scsi_bidi_cmnd(cmd
)) {
831 * Bidi commands Must be complete as a whole,
832 * both sides at once.
834 scsi_req(req
->next_rq
)->resid_len
= scsi_in(cmd
)->resid
;
835 if (scsi_end_request(req
, 0, blk_rq_bytes(req
),
836 blk_rq_bytes(req
->next_rq
)))
840 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
842 * Certain non BLOCK_PC requests are commands that don't
843 * actually transfer anything (FLUSH), so cannot use
844 * good_bytes != blk_rq_bytes(req) as the signal for an error.
845 * This sets the error explicitly for the problem case.
847 error
= __scsi_error_from_host_byte(cmd
, result
);
850 /* no bidi support for !blk_rq_is_passthrough yet */
851 BUG_ON(blk_bidi_rq(req
));
854 * Next deal with any sectors which we were able to correctly
857 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO
, cmd
,
858 "%u sectors total, %d bytes done.\n",
859 blk_rq_sectors(req
), good_bytes
));
862 * Recovered errors need reporting, but they're always treated
863 * as success, so fiddle the result code here. For BLOCK_PC
864 * we already took a copy of the original into rq->errors which
865 * is what gets returned to the user
867 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
868 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
869 * print since caller wants ATA registers. Only occurs on
870 * SCSI ATA PASS_THROUGH commands when CK_COND=1
872 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
874 else if (!(req
->rq_flags
& RQF_QUIET
))
875 scsi_print_sense(cmd
);
877 /* BLOCK_PC may have set error */
882 * special case: failed zero length commands always need to
883 * drop down into the retry code. Otherwise, if we finished
884 * all bytes in the request we are done now.
886 if (!(blk_rq_bytes(req
) == 0 && error
) &&
887 !scsi_end_request(req
, error
, good_bytes
, 0))
891 * Kill remainder if no retrys.
893 if (error
&& scsi_noretry_cmd(cmd
)) {
894 if (scsi_end_request(req
, error
, blk_rq_bytes(req
), 0))
900 * If there had been no error, but we have leftover bytes in the
901 * requeues just queue the command up again.
906 error
= __scsi_error_from_host_byte(cmd
, result
);
908 if (host_byte(result
) == DID_RESET
) {
909 /* Third party bus reset or reset for error recovery
910 * reasons. Just retry the command and see what
913 action
= ACTION_RETRY
;
914 } else if (sense_valid
&& !sense_deferred
) {
915 switch (sshdr
.sense_key
) {
917 if (cmd
->device
->removable
) {
918 /* Detected disc change. Set a bit
919 * and quietly refuse further access.
921 cmd
->device
->changed
= 1;
922 action
= ACTION_FAIL
;
924 /* Must have been a power glitch, or a
925 * bus reset. Could not have been a
926 * media change, so we just retry the
927 * command and see what happens.
929 action
= ACTION_RETRY
;
932 case ILLEGAL_REQUEST
:
933 /* If we had an ILLEGAL REQUEST returned, then
934 * we may have performed an unsupported
935 * command. The only thing this should be
936 * would be a ten byte read where only a six
937 * byte read was supported. Also, on a system
938 * where READ CAPACITY failed, we may have
939 * read past the end of the disk.
941 if ((cmd
->device
->use_10_for_rw
&&
942 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
943 (cmd
->cmnd
[0] == READ_10
||
944 cmd
->cmnd
[0] == WRITE_10
)) {
945 /* This will issue a new 6-byte command. */
946 cmd
->device
->use_10_for_rw
= 0;
947 action
= ACTION_REPREP
;
948 } else if (sshdr
.asc
== 0x10) /* DIX */ {
949 action
= ACTION_FAIL
;
951 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
952 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
953 action
= ACTION_FAIL
;
956 action
= ACTION_FAIL
;
958 case ABORTED_COMMAND
:
959 action
= ACTION_FAIL
;
960 if (sshdr
.asc
== 0x10) /* DIF */
964 /* If the device is in the process of becoming
965 * ready, or has a temporary blockage, retry.
967 if (sshdr
.asc
== 0x04) {
968 switch (sshdr
.ascq
) {
969 case 0x01: /* becoming ready */
970 case 0x04: /* format in progress */
971 case 0x05: /* rebuild in progress */
972 case 0x06: /* recalculation in progress */
973 case 0x07: /* operation in progress */
974 case 0x08: /* Long write in progress */
975 case 0x09: /* self test in progress */
976 case 0x14: /* space allocation in progress */
977 action
= ACTION_DELAYED_RETRY
;
980 action
= ACTION_FAIL
;
984 action
= ACTION_FAIL
;
986 case VOLUME_OVERFLOW
:
987 /* See SSC3rXX or current. */
988 action
= ACTION_FAIL
;
991 action
= ACTION_FAIL
;
995 action
= ACTION_FAIL
;
997 if (action
!= ACTION_FAIL
&&
998 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
))
999 action
= ACTION_FAIL
;
1003 /* Give up and fail the remainder of the request */
1004 if (!(req
->rq_flags
& RQF_QUIET
)) {
1005 static DEFINE_RATELIMIT_STATE(_rs
,
1006 DEFAULT_RATELIMIT_INTERVAL
,
1007 DEFAULT_RATELIMIT_BURST
);
1009 if (unlikely(scsi_logging_level
))
1010 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
1011 SCSI_LOG_MLCOMPLETE_BITS
);
1014 * if logging is enabled the failure will be printed
1015 * in scsi_log_completion(), so avoid duplicate messages
1017 if (!level
&& __ratelimit(&_rs
)) {
1018 scsi_print_result(cmd
, NULL
, FAILED
);
1019 if (driver_byte(result
) & DRIVER_SENSE
)
1020 scsi_print_sense(cmd
);
1021 scsi_print_command(cmd
);
1024 if (!scsi_end_request(req
, error
, blk_rq_err_bytes(req
), 0))
1029 /* Unprep the request and put it back at the head of the queue.
1030 * A new command will be prepared and issued.
1033 cmd
->request
->rq_flags
&= ~RQF_DONTPREP
;
1034 scsi_mq_uninit_cmd(cmd
);
1035 scsi_mq_requeue_cmd(cmd
);
1037 scsi_release_buffers(cmd
);
1038 scsi_requeue_command(q
, cmd
);
1042 /* Retry the same command immediately */
1043 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1045 case ACTION_DELAYED_RETRY
:
1046 /* Retry the same command after a delay */
1047 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1052 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
)
1057 * If sg table allocation fails, requeue request later.
1059 if (unlikely(sg_alloc_table_chained(&sdb
->table
,
1060 blk_rq_nr_phys_segments(req
), sdb
->table
.sgl
)))
1061 return BLKPREP_DEFER
;
1064 * Next, walk the list, and fill in the addresses and sizes of
1067 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1068 BUG_ON(count
> sdb
->table
.nents
);
1069 sdb
->table
.nents
= count
;
1070 sdb
->length
= blk_rq_payload_bytes(req
);
1075 * Function: scsi_init_io()
1077 * Purpose: SCSI I/O initialize function.
1079 * Arguments: cmd - Command descriptor we wish to initialize
1081 * Returns: 0 on success
1082 * BLKPREP_DEFER if the failure is retryable
1083 * BLKPREP_KILL if the failure is fatal
1085 int scsi_init_io(struct scsi_cmnd
*cmd
)
1087 struct scsi_device
*sdev
= cmd
->device
;
1088 struct request
*rq
= cmd
->request
;
1089 bool is_mq
= (rq
->mq_ctx
!= NULL
);
1092 BUG_ON(!blk_rq_nr_phys_segments(rq
));
1094 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1098 if (blk_bidi_rq(rq
)) {
1099 if (!rq
->q
->mq_ops
) {
1100 struct scsi_data_buffer
*bidi_sdb
=
1101 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1103 error
= BLKPREP_DEFER
;
1107 rq
->next_rq
->special
= bidi_sdb
;
1110 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1115 if (blk_integrity_rq(rq
)) {
1116 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1119 if (prot_sdb
== NULL
) {
1121 * This can happen if someone (e.g. multipath)
1122 * queues a command to a device on an adapter
1123 * that does not support DIX.
1126 error
= BLKPREP_KILL
;
1130 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1132 if (sg_alloc_table_chained(&prot_sdb
->table
, ivecs
,
1133 prot_sdb
->table
.sgl
)) {
1134 error
= BLKPREP_DEFER
;
1138 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1139 prot_sdb
->table
.sgl
);
1140 BUG_ON(unlikely(count
> ivecs
));
1141 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1143 cmd
->prot_sdb
= prot_sdb
;
1144 cmd
->prot_sdb
->table
.nents
= count
;
1150 scsi_mq_free_sgtables(cmd
);
1152 scsi_release_buffers(cmd
);
1153 cmd
->request
->special
= NULL
;
1154 scsi_put_command(cmd
);
1155 put_device(&sdev
->sdev_gendev
);
1159 EXPORT_SYMBOL(scsi_init_io
);
1161 void scsi_init_command(struct scsi_device
*dev
, struct scsi_cmnd
*cmd
)
1163 void *buf
= cmd
->sense_buffer
;
1164 void *prot
= cmd
->prot_sdb
;
1165 unsigned long flags
;
1167 /* zero out the cmd, except for the embedded scsi_request */
1168 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1169 sizeof(*cmd
) - sizeof(cmd
->req
));
1172 cmd
->sense_buffer
= buf
;
1173 cmd
->prot_sdb
= prot
;
1174 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1175 cmd
->jiffies_at_alloc
= jiffies
;
1177 spin_lock_irqsave(&dev
->list_lock
, flags
);
1178 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
1179 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
1182 static int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1184 struct scsi_cmnd
*cmd
= req
->special
;
1187 * BLOCK_PC requests may transfer data, in which case they must
1188 * a bio attached to them. Or they might contain a SCSI command
1189 * that does not transfer data, in which case they may optionally
1190 * submit a request without an attached bio.
1193 int ret
= scsi_init_io(cmd
);
1197 BUG_ON(blk_rq_bytes(req
));
1199 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1202 cmd
->cmd_len
= scsi_req(req
)->cmd_len
;
1203 cmd
->cmnd
= scsi_req(req
)->cmd
;
1204 cmd
->transfersize
= blk_rq_bytes(req
);
1205 cmd
->allowed
= req
->retries
;
1210 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1211 * that still need to be translated to SCSI CDBs from the ULD.
1213 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1215 struct scsi_cmnd
*cmd
= req
->special
;
1217 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1218 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1219 if (ret
!= BLKPREP_OK
)
1223 cmd
->cmnd
= scsi_req(req
)->cmd
= scsi_req(req
)->__cmd
;
1224 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1225 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1228 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1230 struct scsi_cmnd
*cmd
= req
->special
;
1232 if (!blk_rq_bytes(req
))
1233 cmd
->sc_data_direction
= DMA_NONE
;
1234 else if (rq_data_dir(req
) == WRITE
)
1235 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1237 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1239 switch (req
->cmd_type
) {
1241 return scsi_setup_fs_cmnd(sdev
, req
);
1242 case REQ_TYPE_BLOCK_PC
:
1243 return scsi_setup_blk_pc_cmnd(sdev
, req
);
1245 return BLKPREP_KILL
;
1250 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1252 int ret
= BLKPREP_OK
;
1255 * If the device is not in running state we will reject some
1258 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1259 switch (sdev
->sdev_state
) {
1261 case SDEV_TRANSPORT_OFFLINE
:
1263 * If the device is offline we refuse to process any
1264 * commands. The device must be brought online
1265 * before trying any recovery commands.
1267 sdev_printk(KERN_ERR
, sdev
,
1268 "rejecting I/O to offline device\n");
1273 * If the device is fully deleted, we refuse to
1274 * process any commands as well.
1276 sdev_printk(KERN_ERR
, sdev
,
1277 "rejecting I/O to dead device\n");
1281 case SDEV_CREATED_BLOCK
:
1282 ret
= BLKPREP_DEFER
;
1286 * If the devices is blocked we defer normal commands.
1288 if (!(req
->rq_flags
& RQF_PREEMPT
))
1289 ret
= BLKPREP_DEFER
;
1293 * For any other not fully online state we only allow
1294 * special commands. In particular any user initiated
1295 * command is not allowed.
1297 if (!(req
->rq_flags
& RQF_PREEMPT
))
1306 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1308 struct scsi_device
*sdev
= q
->queuedata
;
1312 case BLKPREP_INVALID
:
1313 req
->errors
= DID_NO_CONNECT
<< 16;
1314 /* release the command and kill it */
1316 struct scsi_cmnd
*cmd
= req
->special
;
1317 scsi_release_buffers(cmd
);
1318 scsi_put_command(cmd
);
1319 put_device(&sdev
->sdev_gendev
);
1320 req
->special
= NULL
;
1325 * If we defer, the blk_peek_request() returns NULL, but the
1326 * queue must be restarted, so we schedule a callback to happen
1329 if (atomic_read(&sdev
->device_busy
) == 0)
1330 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1333 req
->rq_flags
|= RQF_DONTPREP
;
1339 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1341 struct scsi_device
*sdev
= q
->queuedata
;
1342 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1345 ret
= scsi_prep_state_check(sdev
, req
);
1346 if (ret
!= BLKPREP_OK
)
1349 if (!req
->special
) {
1350 /* Bail if we can't get a reference to the device */
1351 if (unlikely(!get_device(&sdev
->sdev_gendev
))) {
1352 ret
= BLKPREP_DEFER
;
1356 scsi_init_command(sdev
, cmd
);
1360 cmd
->tag
= req
->tag
;
1362 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1364 ret
= scsi_setup_cmnd(sdev
, req
);
1366 return scsi_prep_return(q
, req
, ret
);
1369 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1371 scsi_uninit_cmd(req
->special
);
1375 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1378 * Called with the queue_lock held.
1380 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1381 struct scsi_device
*sdev
)
1385 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1386 if (atomic_read(&sdev
->device_blocked
)) {
1391 * unblock after device_blocked iterates to zero
1393 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1395 * For the MQ case we take care of this in the caller.
1398 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1401 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1402 "unblocking device at zero depth\n"));
1405 if (busy
>= sdev
->queue_depth
)
1410 atomic_dec(&sdev
->device_busy
);
1415 * scsi_target_queue_ready: checks if there we can send commands to target
1416 * @sdev: scsi device on starget to check.
1418 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1419 struct scsi_device
*sdev
)
1421 struct scsi_target
*starget
= scsi_target(sdev
);
1424 if (starget
->single_lun
) {
1425 spin_lock_irq(shost
->host_lock
);
1426 if (starget
->starget_sdev_user
&&
1427 starget
->starget_sdev_user
!= sdev
) {
1428 spin_unlock_irq(shost
->host_lock
);
1431 starget
->starget_sdev_user
= sdev
;
1432 spin_unlock_irq(shost
->host_lock
);
1435 if (starget
->can_queue
<= 0)
1438 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1439 if (atomic_read(&starget
->target_blocked
) > 0) {
1444 * unblock after target_blocked iterates to zero
1446 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1449 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1450 "unblocking target at zero depth\n"));
1453 if (busy
>= starget
->can_queue
)
1459 spin_lock_irq(shost
->host_lock
);
1460 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1461 spin_unlock_irq(shost
->host_lock
);
1463 if (starget
->can_queue
> 0)
1464 atomic_dec(&starget
->target_busy
);
1469 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1470 * return 0. We must end up running the queue again whenever 0 is
1471 * returned, else IO can hang.
1473 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1474 struct Scsi_Host
*shost
,
1475 struct scsi_device
*sdev
)
1479 if (scsi_host_in_recovery(shost
))
1482 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1483 if (atomic_read(&shost
->host_blocked
) > 0) {
1488 * unblock after host_blocked iterates to zero
1490 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1494 shost_printk(KERN_INFO
, shost
,
1495 "unblocking host at zero depth\n"));
1498 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1500 if (shost
->host_self_blocked
)
1503 /* We're OK to process the command, so we can't be starved */
1504 if (!list_empty(&sdev
->starved_entry
)) {
1505 spin_lock_irq(shost
->host_lock
);
1506 if (!list_empty(&sdev
->starved_entry
))
1507 list_del_init(&sdev
->starved_entry
);
1508 spin_unlock_irq(shost
->host_lock
);
1514 spin_lock_irq(shost
->host_lock
);
1515 if (list_empty(&sdev
->starved_entry
))
1516 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1517 spin_unlock_irq(shost
->host_lock
);
1519 atomic_dec(&shost
->host_busy
);
1524 * Busy state exporting function for request stacking drivers.
1526 * For efficiency, no lock is taken to check the busy state of
1527 * shost/starget/sdev, since the returned value is not guaranteed and
1528 * may be changed after request stacking drivers call the function,
1529 * regardless of taking lock or not.
1531 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1532 * needs to return 'not busy'. Otherwise, request stacking drivers
1533 * may hold requests forever.
1535 static int scsi_lld_busy(struct request_queue
*q
)
1537 struct scsi_device
*sdev
= q
->queuedata
;
1538 struct Scsi_Host
*shost
;
1540 if (blk_queue_dying(q
))
1546 * Ignore host/starget busy state.
1547 * Since block layer does not have a concept of fairness across
1548 * multiple queues, congestion of host/starget needs to be handled
1551 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1558 * Kill a request for a dead device
1560 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1562 struct scsi_cmnd
*cmd
= req
->special
;
1563 struct scsi_device
*sdev
;
1564 struct scsi_target
*starget
;
1565 struct Scsi_Host
*shost
;
1567 blk_start_request(req
);
1569 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1572 starget
= scsi_target(sdev
);
1574 scsi_init_cmd_errh(cmd
);
1575 cmd
->result
= DID_NO_CONNECT
<< 16;
1576 atomic_inc(&cmd
->device
->iorequest_cnt
);
1579 * SCSI request completion path will do scsi_device_unbusy(),
1580 * bump busy counts. To bump the counters, we need to dance
1581 * with the locks as normal issue path does.
1583 atomic_inc(&sdev
->device_busy
);
1584 atomic_inc(&shost
->host_busy
);
1585 if (starget
->can_queue
> 0)
1586 atomic_inc(&starget
->target_busy
);
1588 blk_complete_request(req
);
1591 static void scsi_softirq_done(struct request
*rq
)
1593 struct scsi_cmnd
*cmd
= rq
->special
;
1594 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1597 INIT_LIST_HEAD(&cmd
->eh_entry
);
1599 atomic_inc(&cmd
->device
->iodone_cnt
);
1601 atomic_inc(&cmd
->device
->ioerr_cnt
);
1603 disposition
= scsi_decide_disposition(cmd
);
1604 if (disposition
!= SUCCESS
&&
1605 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1606 sdev_printk(KERN_ERR
, cmd
->device
,
1607 "timing out command, waited %lus\n",
1609 disposition
= SUCCESS
;
1612 scsi_log_completion(cmd
, disposition
);
1614 switch (disposition
) {
1616 scsi_finish_command(cmd
);
1619 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1621 case ADD_TO_MLQUEUE
:
1622 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1625 if (!scsi_eh_scmd_add(cmd
, 0))
1626 scsi_finish_command(cmd
);
1631 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1632 * @cmd: command block we are dispatching.
1634 * Return: nonzero return request was rejected and device's queue needs to be
1637 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1639 struct Scsi_Host
*host
= cmd
->device
->host
;
1642 atomic_inc(&cmd
->device
->iorequest_cnt
);
1644 /* check if the device is still usable */
1645 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1646 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1647 * returns an immediate error upwards, and signals
1648 * that the device is no longer present */
1649 cmd
->result
= DID_NO_CONNECT
<< 16;
1653 /* Check to see if the scsi lld made this device blocked. */
1654 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1656 * in blocked state, the command is just put back on
1657 * the device queue. The suspend state has already
1658 * blocked the queue so future requests should not
1659 * occur until the device transitions out of the
1662 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1663 "queuecommand : device blocked\n"));
1664 return SCSI_MLQUEUE_DEVICE_BUSY
;
1667 /* Store the LUN value in cmnd, if needed. */
1668 if (cmd
->device
->lun_in_cdb
)
1669 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1670 (cmd
->device
->lun
<< 5 & 0xe0);
1675 * Before we queue this command, check if the command
1676 * length exceeds what the host adapter can handle.
1678 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1679 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1680 "queuecommand : command too long. "
1681 "cdb_size=%d host->max_cmd_len=%d\n",
1682 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1683 cmd
->result
= (DID_ABORT
<< 16);
1687 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1688 cmd
->result
= (DID_NO_CONNECT
<< 16);
1693 trace_scsi_dispatch_cmd_start(cmd
);
1694 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1696 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1697 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1698 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1699 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1701 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1702 "queuecommand : request rejected\n"));
1707 cmd
->scsi_done(cmd
);
1712 * scsi_done - Invoke completion on finished SCSI command.
1713 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1714 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1716 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1717 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1718 * calls blk_complete_request() for further processing.
1720 * This function is interrupt context safe.
1722 static void scsi_done(struct scsi_cmnd
*cmd
)
1724 trace_scsi_dispatch_cmd_done(cmd
);
1725 blk_complete_request(cmd
->request
);
1729 * Function: scsi_request_fn()
1731 * Purpose: Main strategy routine for SCSI.
1733 * Arguments: q - Pointer to actual queue.
1737 * Lock status: IO request lock assumed to be held when called.
1739 static void scsi_request_fn(struct request_queue
*q
)
1740 __releases(q
->queue_lock
)
1741 __acquires(q
->queue_lock
)
1743 struct scsi_device
*sdev
= q
->queuedata
;
1744 struct Scsi_Host
*shost
;
1745 struct scsi_cmnd
*cmd
;
1746 struct request
*req
;
1749 * To start with, we keep looping until the queue is empty, or until
1750 * the host is no longer able to accept any more requests.
1756 * get next queueable request. We do this early to make sure
1757 * that the request is fully prepared even if we cannot
1760 req
= blk_peek_request(q
);
1764 if (unlikely(!scsi_device_online(sdev
))) {
1765 sdev_printk(KERN_ERR
, sdev
,
1766 "rejecting I/O to offline device\n");
1767 scsi_kill_request(req
, q
);
1771 if (!scsi_dev_queue_ready(q
, sdev
))
1775 * Remove the request from the request list.
1777 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1778 blk_start_request(req
);
1780 spin_unlock_irq(q
->queue_lock
);
1782 if (unlikely(cmd
== NULL
)) {
1783 printk(KERN_CRIT
"impossible request in %s.\n"
1784 "please mail a stack trace to "
1785 "linux-scsi@vger.kernel.org\n",
1787 blk_dump_rq_flags(req
, "foo");
1792 * We hit this when the driver is using a host wide
1793 * tag map. For device level tag maps the queue_depth check
1794 * in the device ready fn would prevent us from trying
1795 * to allocate a tag. Since the map is a shared host resource
1796 * we add the dev to the starved list so it eventually gets
1797 * a run when a tag is freed.
1799 if (blk_queue_tagged(q
) && !(req
->rq_flags
& RQF_QUEUED
)) {
1800 spin_lock_irq(shost
->host_lock
);
1801 if (list_empty(&sdev
->starved_entry
))
1802 list_add_tail(&sdev
->starved_entry
,
1803 &shost
->starved_list
);
1804 spin_unlock_irq(shost
->host_lock
);
1808 if (!scsi_target_queue_ready(shost
, sdev
))
1811 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1812 goto host_not_ready
;
1814 if (sdev
->simple_tags
)
1815 cmd
->flags
|= SCMD_TAGGED
;
1817 cmd
->flags
&= ~SCMD_TAGGED
;
1820 * Finally, initialize any error handling parameters, and set up
1821 * the timers for timeouts.
1823 scsi_init_cmd_errh(cmd
);
1826 * Dispatch the command to the low-level driver.
1828 cmd
->scsi_done
= scsi_done
;
1829 rtn
= scsi_dispatch_cmd(cmd
);
1831 scsi_queue_insert(cmd
, rtn
);
1832 spin_lock_irq(q
->queue_lock
);
1835 spin_lock_irq(q
->queue_lock
);
1841 if (scsi_target(sdev
)->can_queue
> 0)
1842 atomic_dec(&scsi_target(sdev
)->target_busy
);
1845 * lock q, handle tag, requeue req, and decrement device_busy. We
1846 * must return with queue_lock held.
1848 * Decrementing device_busy without checking it is OK, as all such
1849 * cases (host limits or settings) should run the queue at some
1852 spin_lock_irq(q
->queue_lock
);
1853 blk_requeue_request(q
, req
);
1854 atomic_dec(&sdev
->device_busy
);
1856 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1857 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1860 static inline int prep_to_mq(int ret
)
1864 return BLK_MQ_RQ_QUEUE_OK
;
1866 return BLK_MQ_RQ_QUEUE_BUSY
;
1868 return BLK_MQ_RQ_QUEUE_ERROR
;
1872 static int scsi_mq_prep_fn(struct request
*req
)
1874 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1875 struct scsi_device
*sdev
= req
->q
->queuedata
;
1876 struct Scsi_Host
*shost
= sdev
->host
;
1877 unsigned char *sense_buf
= cmd
->sense_buffer
;
1878 struct scatterlist
*sg
;
1880 /* zero out the cmd, except for the embedded scsi_request */
1881 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1882 sizeof(*cmd
) - sizeof(cmd
->req
));
1888 cmd
->sense_buffer
= sense_buf
;
1890 cmd
->tag
= req
->tag
;
1892 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1894 INIT_LIST_HEAD(&cmd
->list
);
1895 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1896 cmd
->jiffies_at_alloc
= jiffies
;
1898 if (shost
->use_cmd_list
) {
1899 spin_lock_irq(&sdev
->list_lock
);
1900 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1901 spin_unlock_irq(&sdev
->list_lock
);
1904 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1905 cmd
->sdb
.table
.sgl
= sg
;
1907 if (scsi_host_get_prot(shost
)) {
1908 cmd
->prot_sdb
= (void *)sg
+
1910 shost
->sg_tablesize
, SG_CHUNK_SIZE
) *
1911 sizeof(struct scatterlist
);
1912 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1914 cmd
->prot_sdb
->table
.sgl
=
1915 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1918 if (blk_bidi_rq(req
)) {
1919 struct request
*next_rq
= req
->next_rq
;
1920 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1922 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1923 bidi_sdb
->table
.sgl
=
1924 (struct scatterlist
*)(bidi_sdb
+ 1);
1926 next_rq
->special
= bidi_sdb
;
1929 blk_mq_start_request(req
);
1931 return scsi_setup_cmnd(sdev
, req
);
1934 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1936 trace_scsi_dispatch_cmd_done(cmd
);
1937 blk_mq_complete_request(cmd
->request
, cmd
->request
->errors
);
1940 static int scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1941 const struct blk_mq_queue_data
*bd
)
1943 struct request
*req
= bd
->rq
;
1944 struct request_queue
*q
= req
->q
;
1945 struct scsi_device
*sdev
= q
->queuedata
;
1946 struct Scsi_Host
*shost
= sdev
->host
;
1947 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1951 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1952 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1955 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1956 if (!get_device(&sdev
->sdev_gendev
))
1959 if (!scsi_dev_queue_ready(q
, sdev
))
1960 goto out_put_device
;
1961 if (!scsi_target_queue_ready(shost
, sdev
))
1962 goto out_dec_device_busy
;
1963 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1964 goto out_dec_target_busy
;
1966 if (!(req
->rq_flags
& RQF_DONTPREP
)) {
1967 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1968 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1969 goto out_dec_host_busy
;
1970 req
->rq_flags
|= RQF_DONTPREP
;
1972 blk_mq_start_request(req
);
1975 if (sdev
->simple_tags
)
1976 cmd
->flags
|= SCMD_TAGGED
;
1978 cmd
->flags
&= ~SCMD_TAGGED
;
1980 scsi_init_cmd_errh(cmd
);
1981 cmd
->scsi_done
= scsi_mq_done
;
1983 reason
= scsi_dispatch_cmd(cmd
);
1985 scsi_set_blocked(cmd
, reason
);
1986 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1987 goto out_dec_host_busy
;
1990 return BLK_MQ_RQ_QUEUE_OK
;
1993 atomic_dec(&shost
->host_busy
);
1994 out_dec_target_busy
:
1995 if (scsi_target(sdev
)->can_queue
> 0)
1996 atomic_dec(&scsi_target(sdev
)->target_busy
);
1997 out_dec_device_busy
:
1998 atomic_dec(&sdev
->device_busy
);
2000 put_device(&sdev
->sdev_gendev
);
2003 case BLK_MQ_RQ_QUEUE_BUSY
:
2004 if (atomic_read(&sdev
->device_busy
) == 0 &&
2005 !scsi_device_blocked(sdev
))
2006 blk_mq_delay_queue(hctx
, SCSI_QUEUE_DELAY
);
2008 case BLK_MQ_RQ_QUEUE_ERROR
:
2010 * Make sure to release all allocated ressources when
2011 * we hit an error, as we will never see this command
2014 if (req
->rq_flags
& RQF_DONTPREP
)
2015 scsi_mq_uninit_cmd(cmd
);
2023 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
2027 return BLK_EH_RESET_TIMER
;
2028 return scsi_times_out(req
);
2031 static int scsi_init_request(void *data
, struct request
*rq
,
2032 unsigned int hctx_idx
, unsigned int request_idx
,
2033 unsigned int numa_node
)
2035 struct Scsi_Host
*shost
= data
;
2036 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2039 scsi_alloc_sense_buffer(shost
, GFP_KERNEL
, numa_node
);
2040 if (!cmd
->sense_buffer
)
2042 cmd
->req
.sense
= cmd
->sense_buffer
;
2046 static void scsi_exit_request(void *data
, struct request
*rq
,
2047 unsigned int hctx_idx
, unsigned int request_idx
)
2049 struct Scsi_Host
*shost
= data
;
2050 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2052 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2055 static int scsi_map_queues(struct blk_mq_tag_set
*set
)
2057 struct Scsi_Host
*shost
= container_of(set
, struct Scsi_Host
, tag_set
);
2059 if (shost
->hostt
->map_queues
)
2060 return shost
->hostt
->map_queues(shost
);
2061 return blk_mq_map_queues(set
);
2064 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2066 struct device
*host_dev
;
2067 u64 bounce_limit
= 0xffffffff;
2069 if (shost
->unchecked_isa_dma
)
2070 return BLK_BOUNCE_ISA
;
2072 * Platforms with virtual-DMA translation
2073 * hardware have no practical limit.
2075 if (!PCI_DMA_BUS_IS_PHYS
)
2076 return BLK_BOUNCE_ANY
;
2078 host_dev
= scsi_get_device(shost
);
2079 if (host_dev
&& host_dev
->dma_mask
)
2080 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2082 return bounce_limit
;
2085 void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2087 struct device
*dev
= shost
->dma_dev
;
2090 * this limit is imposed by hardware restrictions
2092 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
2095 if (scsi_host_prot_dma(shost
)) {
2096 shost
->sg_prot_tablesize
=
2097 min_not_zero(shost
->sg_prot_tablesize
,
2098 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
2099 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
2100 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
2103 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
2104 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
2105 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
2106 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
2108 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2110 if (!shost
->use_clustering
)
2111 q
->limits
.cluster
= 0;
2114 * set a reasonable default alignment on word boundaries: the
2115 * host and device may alter it using
2116 * blk_queue_update_dma_alignment() later.
2118 blk_queue_dma_alignment(q
, 0x03);
2120 EXPORT_SYMBOL_GPL(__scsi_init_queue
);
2122 static int scsi_init_rq(struct request_queue
*q
, struct request
*rq
, gfp_t gfp
)
2124 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2125 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2127 memset(cmd
, 0, sizeof(*cmd
));
2129 cmd
->sense_buffer
= scsi_alloc_sense_buffer(shost
, gfp
, NUMA_NO_NODE
);
2130 if (!cmd
->sense_buffer
)
2132 cmd
->req
.sense
= cmd
->sense_buffer
;
2134 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
2135 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp
);
2137 goto fail_free_sense
;
2143 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2148 static void scsi_exit_rq(struct request_queue
*q
, struct request
*rq
)
2150 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2151 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2154 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
2155 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2158 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
2160 struct Scsi_Host
*shost
= sdev
->host
;
2161 struct request_queue
*q
;
2163 q
= blk_alloc_queue_node(GFP_KERNEL
, NUMA_NO_NODE
);
2166 q
->cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
2167 q
->rq_alloc_data
= shost
;
2168 q
->request_fn
= scsi_request_fn
;
2169 q
->init_rq_fn
= scsi_init_rq
;
2170 q
->exit_rq_fn
= scsi_exit_rq
;
2172 if (blk_init_allocated_queue(q
) < 0) {
2173 blk_cleanup_queue(q
);
2177 __scsi_init_queue(shost
, q
);
2178 blk_queue_prep_rq(q
, scsi_prep_fn
);
2179 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2180 blk_queue_softirq_done(q
, scsi_softirq_done
);
2181 blk_queue_rq_timed_out(q
, scsi_times_out
);
2182 blk_queue_lld_busy(q
, scsi_lld_busy
);
2186 static struct blk_mq_ops scsi_mq_ops
= {
2187 .queue_rq
= scsi_queue_rq
,
2188 .complete
= scsi_softirq_done
,
2189 .timeout
= scsi_timeout
,
2190 .init_request
= scsi_init_request
,
2191 .exit_request
= scsi_exit_request
,
2192 .map_queues
= scsi_map_queues
,
2195 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2197 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2198 if (IS_ERR(sdev
->request_queue
))
2201 sdev
->request_queue
->queuedata
= sdev
;
2202 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2203 return sdev
->request_queue
;
2206 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2208 unsigned int cmd_size
, sgl_size
, tbl_size
;
2210 tbl_size
= shost
->sg_tablesize
;
2211 if (tbl_size
> SG_CHUNK_SIZE
)
2212 tbl_size
= SG_CHUNK_SIZE
;
2213 sgl_size
= tbl_size
* sizeof(struct scatterlist
);
2214 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2215 if (scsi_host_get_prot(shost
))
2216 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2218 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2219 shost
->tag_set
.ops
= &scsi_mq_ops
;
2220 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2221 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2222 shost
->tag_set
.cmd_size
= cmd_size
;
2223 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2224 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2225 shost
->tag_set
.flags
|=
2226 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2227 shost
->tag_set
.driver_data
= shost
;
2229 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2232 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2234 blk_mq_free_tag_set(&shost
->tag_set
);
2238 * Function: scsi_block_requests()
2240 * Purpose: Utility function used by low-level drivers to prevent further
2241 * commands from being queued to the device.
2243 * Arguments: shost - Host in question
2247 * Lock status: No locks are assumed held.
2249 * Notes: There is no timer nor any other means by which the requests
2250 * get unblocked other than the low-level driver calling
2251 * scsi_unblock_requests().
2253 void scsi_block_requests(struct Scsi_Host
*shost
)
2255 shost
->host_self_blocked
= 1;
2257 EXPORT_SYMBOL(scsi_block_requests
);
2260 * Function: scsi_unblock_requests()
2262 * Purpose: Utility function used by low-level drivers to allow further
2263 * commands from being queued to the device.
2265 * Arguments: shost - Host in question
2269 * Lock status: No locks are assumed held.
2271 * Notes: There is no timer nor any other means by which the requests
2272 * get unblocked other than the low-level driver calling
2273 * scsi_unblock_requests().
2275 * This is done as an API function so that changes to the
2276 * internals of the scsi mid-layer won't require wholesale
2277 * changes to drivers that use this feature.
2279 void scsi_unblock_requests(struct Scsi_Host
*shost
)
2281 shost
->host_self_blocked
= 0;
2282 scsi_run_host_queues(shost
);
2284 EXPORT_SYMBOL(scsi_unblock_requests
);
2286 int __init
scsi_init_queue(void)
2288 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
2289 sizeof(struct scsi_data_buffer
),
2291 if (!scsi_sdb_cache
) {
2292 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
2299 void scsi_exit_queue(void)
2301 kmem_cache_destroy(scsi_sense_cache
);
2302 kmem_cache_destroy(scsi_sense_isadma_cache
);
2303 kmem_cache_destroy(scsi_sdb_cache
);
2307 * scsi_mode_select - issue a mode select
2308 * @sdev: SCSI device to be queried
2309 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2310 * @sp: Save page bit (0 == don't save, 1 == save)
2311 * @modepage: mode page being requested
2312 * @buffer: request buffer (may not be smaller than eight bytes)
2313 * @len: length of request buffer.
2314 * @timeout: command timeout
2315 * @retries: number of retries before failing
2316 * @data: returns a structure abstracting the mode header data
2317 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2318 * must be SCSI_SENSE_BUFFERSIZE big.
2320 * Returns zero if successful; negative error number or scsi
2325 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
2326 unsigned char *buffer
, int len
, int timeout
, int retries
,
2327 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2329 unsigned char cmd
[10];
2330 unsigned char *real_buffer
;
2333 memset(cmd
, 0, sizeof(cmd
));
2334 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
2336 if (sdev
->use_10_for_ms
) {
2339 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
2342 memcpy(real_buffer
+ 8, buffer
, len
);
2346 real_buffer
[2] = data
->medium_type
;
2347 real_buffer
[3] = data
->device_specific
;
2348 real_buffer
[4] = data
->longlba
? 0x01 : 0;
2350 real_buffer
[6] = data
->block_descriptor_length
>> 8;
2351 real_buffer
[7] = data
->block_descriptor_length
;
2353 cmd
[0] = MODE_SELECT_10
;
2357 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2361 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2364 memcpy(real_buffer
+ 4, buffer
, len
);
2367 real_buffer
[1] = data
->medium_type
;
2368 real_buffer
[2] = data
->device_specific
;
2369 real_buffer
[3] = data
->block_descriptor_length
;
2372 cmd
[0] = MODE_SELECT
;
2376 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2377 sshdr
, timeout
, retries
, NULL
);
2381 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2384 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2385 * @sdev: SCSI device to be queried
2386 * @dbd: set if mode sense will allow block descriptors to be returned
2387 * @modepage: mode page being requested
2388 * @buffer: request buffer (may not be smaller than eight bytes)
2389 * @len: length of request buffer.
2390 * @timeout: command timeout
2391 * @retries: number of retries before failing
2392 * @data: returns a structure abstracting the mode header data
2393 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2394 * must be SCSI_SENSE_BUFFERSIZE big.
2396 * Returns zero if unsuccessful, or the header offset (either 4
2397 * or 8 depending on whether a six or ten byte command was
2398 * issued) if successful.
2401 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2402 unsigned char *buffer
, int len
, int timeout
, int retries
,
2403 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2405 unsigned char cmd
[12];
2408 int result
, retry_count
= retries
;
2409 struct scsi_sense_hdr my_sshdr
;
2411 memset(data
, 0, sizeof(*data
));
2412 memset(&cmd
[0], 0, 12);
2413 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2416 /* caller might not be interested in sense, but we need it */
2421 use_10_for_ms
= sdev
->use_10_for_ms
;
2423 if (use_10_for_ms
) {
2427 cmd
[0] = MODE_SENSE_10
;
2434 cmd
[0] = MODE_SENSE
;
2439 memset(buffer
, 0, len
);
2441 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2442 sshdr
, timeout
, retries
, NULL
);
2444 /* This code looks awful: what it's doing is making sure an
2445 * ILLEGAL REQUEST sense return identifies the actual command
2446 * byte as the problem. MODE_SENSE commands can return
2447 * ILLEGAL REQUEST if the code page isn't supported */
2449 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2450 (driver_byte(result
) & DRIVER_SENSE
)) {
2451 if (scsi_sense_valid(sshdr
)) {
2452 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2453 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2455 * Invalid command operation code
2457 sdev
->use_10_for_ms
= 0;
2463 if(scsi_status_is_good(result
)) {
2464 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2465 (modepage
== 6 || modepage
== 8))) {
2466 /* Initio breakage? */
2469 data
->medium_type
= 0;
2470 data
->device_specific
= 0;
2472 data
->block_descriptor_length
= 0;
2473 } else if(use_10_for_ms
) {
2474 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2475 data
->medium_type
= buffer
[2];
2476 data
->device_specific
= buffer
[3];
2477 data
->longlba
= buffer
[4] & 0x01;
2478 data
->block_descriptor_length
= buffer
[6]*256
2481 data
->length
= buffer
[0] + 1;
2482 data
->medium_type
= buffer
[1];
2483 data
->device_specific
= buffer
[2];
2484 data
->block_descriptor_length
= buffer
[3];
2486 data
->header_length
= header_length
;
2487 } else if ((status_byte(result
) == CHECK_CONDITION
) &&
2488 scsi_sense_valid(sshdr
) &&
2489 sshdr
->sense_key
== UNIT_ATTENTION
&& retry_count
) {
2496 EXPORT_SYMBOL(scsi_mode_sense
);
2499 * scsi_test_unit_ready - test if unit is ready
2500 * @sdev: scsi device to change the state of.
2501 * @timeout: command timeout
2502 * @retries: number of retries before failing
2503 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2504 * returning sense. Make sure that this is cleared before passing
2507 * Returns zero if unsuccessful or an error if TUR failed. For
2508 * removable media, UNIT_ATTENTION sets ->changed flag.
2511 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2512 struct scsi_sense_hdr
*sshdr_external
)
2515 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2517 struct scsi_sense_hdr
*sshdr
;
2520 if (!sshdr_external
)
2521 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2523 sshdr
= sshdr_external
;
2525 /* try to eat the UNIT_ATTENTION if there are enough retries */
2527 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2528 timeout
, retries
, NULL
);
2529 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2530 sshdr
->sense_key
== UNIT_ATTENTION
)
2532 } while (scsi_sense_valid(sshdr
) &&
2533 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2535 if (!sshdr_external
)
2539 EXPORT_SYMBOL(scsi_test_unit_ready
);
2542 * scsi_device_set_state - Take the given device through the device state model.
2543 * @sdev: scsi device to change the state of.
2544 * @state: state to change to.
2546 * Returns zero if unsuccessful or an error if the requested
2547 * transition is illegal.
2550 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2552 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2554 if (state
== oldstate
)
2560 case SDEV_CREATED_BLOCK
:
2571 case SDEV_TRANSPORT_OFFLINE
:
2584 case SDEV_TRANSPORT_OFFLINE
:
2592 case SDEV_TRANSPORT_OFFLINE
:
2607 case SDEV_CREATED_BLOCK
:
2614 case SDEV_CREATED_BLOCK
:
2629 case SDEV_TRANSPORT_OFFLINE
:
2642 case SDEV_TRANSPORT_OFFLINE
:
2644 case SDEV_CREATED_BLOCK
:
2652 sdev
->sdev_state
= state
;
2656 SCSI_LOG_ERROR_RECOVERY(1,
2657 sdev_printk(KERN_ERR
, sdev
,
2658 "Illegal state transition %s->%s",
2659 scsi_device_state_name(oldstate
),
2660 scsi_device_state_name(state
))
2664 EXPORT_SYMBOL(scsi_device_set_state
);
2667 * sdev_evt_emit - emit a single SCSI device uevent
2668 * @sdev: associated SCSI device
2669 * @evt: event to emit
2671 * Send a single uevent (scsi_event) to the associated scsi_device.
2673 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2678 switch (evt
->evt_type
) {
2679 case SDEV_EVT_MEDIA_CHANGE
:
2680 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2682 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2683 scsi_rescan_device(&sdev
->sdev_gendev
);
2684 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2686 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2687 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2689 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2690 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2692 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2693 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2695 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2696 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2698 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2699 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2708 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2712 * sdev_evt_thread - send a uevent for each scsi event
2713 * @work: work struct for scsi_device
2715 * Dispatch queued events to their associated scsi_device kobjects
2718 void scsi_evt_thread(struct work_struct
*work
)
2720 struct scsi_device
*sdev
;
2721 enum scsi_device_event evt_type
;
2722 LIST_HEAD(event_list
);
2724 sdev
= container_of(work
, struct scsi_device
, event_work
);
2726 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2727 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2728 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2731 struct scsi_event
*evt
;
2732 struct list_head
*this, *tmp
;
2733 unsigned long flags
;
2735 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2736 list_splice_init(&sdev
->event_list
, &event_list
);
2737 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2739 if (list_empty(&event_list
))
2742 list_for_each_safe(this, tmp
, &event_list
) {
2743 evt
= list_entry(this, struct scsi_event
, node
);
2744 list_del(&evt
->node
);
2745 scsi_evt_emit(sdev
, evt
);
2752 * sdev_evt_send - send asserted event to uevent thread
2753 * @sdev: scsi_device event occurred on
2754 * @evt: event to send
2756 * Assert scsi device event asynchronously.
2758 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2760 unsigned long flags
;
2763 /* FIXME: currently this check eliminates all media change events
2764 * for polled devices. Need to update to discriminate between AN
2765 * and polled events */
2766 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2772 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2773 list_add_tail(&evt
->node
, &sdev
->event_list
);
2774 schedule_work(&sdev
->event_work
);
2775 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2777 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2780 * sdev_evt_alloc - allocate a new scsi event
2781 * @evt_type: type of event to allocate
2782 * @gfpflags: GFP flags for allocation
2784 * Allocates and returns a new scsi_event.
2786 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2789 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2793 evt
->evt_type
= evt_type
;
2794 INIT_LIST_HEAD(&evt
->node
);
2796 /* evt_type-specific initialization, if any */
2798 case SDEV_EVT_MEDIA_CHANGE
:
2799 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2800 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2801 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2802 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2803 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2804 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2812 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2815 * sdev_evt_send_simple - send asserted event to uevent thread
2816 * @sdev: scsi_device event occurred on
2817 * @evt_type: type of event to send
2818 * @gfpflags: GFP flags for allocation
2820 * Assert scsi device event asynchronously, given an event type.
2822 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2823 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2825 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2827 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2832 sdev_evt_send(sdev
, evt
);
2834 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2837 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2838 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2840 static int scsi_request_fn_active(struct scsi_device
*sdev
)
2842 struct request_queue
*q
= sdev
->request_queue
;
2843 int request_fn_active
;
2845 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2847 spin_lock_irq(q
->queue_lock
);
2848 request_fn_active
= q
->request_fn_active
;
2849 spin_unlock_irq(q
->queue_lock
);
2851 return request_fn_active
;
2855 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2856 * @sdev: SCSI device pointer.
2858 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2859 * invoked from scsi_request_fn() have finished.
2861 static void scsi_wait_for_queuecommand(struct scsi_device
*sdev
)
2863 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2865 while (scsi_request_fn_active(sdev
))
2870 * scsi_device_quiesce - Block user issued commands.
2871 * @sdev: scsi device to quiesce.
2873 * This works by trying to transition to the SDEV_QUIESCE state
2874 * (which must be a legal transition). When the device is in this
2875 * state, only special requests will be accepted, all others will
2876 * be deferred. Since special requests may also be requeued requests,
2877 * a successful return doesn't guarantee the device will be
2878 * totally quiescent.
2880 * Must be called with user context, may sleep.
2882 * Returns zero if unsuccessful or an error if not.
2885 scsi_device_quiesce(struct scsi_device
*sdev
)
2887 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2891 scsi_run_queue(sdev
->request_queue
);
2892 while (atomic_read(&sdev
->device_busy
)) {
2893 msleep_interruptible(200);
2894 scsi_run_queue(sdev
->request_queue
);
2898 EXPORT_SYMBOL(scsi_device_quiesce
);
2901 * scsi_device_resume - Restart user issued commands to a quiesced device.
2902 * @sdev: scsi device to resume.
2904 * Moves the device from quiesced back to running and restarts the
2907 * Must be called with user context, may sleep.
2909 void scsi_device_resume(struct scsi_device
*sdev
)
2911 /* check if the device state was mutated prior to resume, and if
2912 * so assume the state is being managed elsewhere (for example
2913 * device deleted during suspend)
2915 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2916 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2918 scsi_run_queue(sdev
->request_queue
);
2920 EXPORT_SYMBOL(scsi_device_resume
);
2923 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2925 scsi_device_quiesce(sdev
);
2929 scsi_target_quiesce(struct scsi_target
*starget
)
2931 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2933 EXPORT_SYMBOL(scsi_target_quiesce
);
2936 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2938 scsi_device_resume(sdev
);
2942 scsi_target_resume(struct scsi_target
*starget
)
2944 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2946 EXPORT_SYMBOL(scsi_target_resume
);
2949 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2950 * @sdev: device to block
2952 * Block request made by scsi lld's to temporarily stop all
2953 * scsi commands on the specified device. May sleep.
2955 * Returns zero if successful or error if not
2958 * This routine transitions the device to the SDEV_BLOCK state
2959 * (which must be a legal transition). When the device is in this
2960 * state, all commands are deferred until the scsi lld reenables
2961 * the device with scsi_device_unblock or device_block_tmo fires.
2963 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2964 * scsi_internal_device_block() has blocked a SCSI device and also
2965 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2968 scsi_internal_device_block(struct scsi_device
*sdev
)
2970 struct request_queue
*q
= sdev
->request_queue
;
2971 unsigned long flags
;
2974 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2976 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2983 * The device has transitioned to SDEV_BLOCK. Stop the
2984 * block layer from calling the midlayer with this device's
2988 blk_mq_quiesce_queue(q
);
2990 spin_lock_irqsave(q
->queue_lock
, flags
);
2992 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2993 scsi_wait_for_queuecommand(sdev
);
2998 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
3001 * scsi_internal_device_unblock - resume a device after a block request
3002 * @sdev: device to resume
3003 * @new_state: state to set devices to after unblocking
3005 * Called by scsi lld's or the midlayer to restart the device queue
3006 * for the previously suspended scsi device. Called from interrupt or
3007 * normal process context.
3009 * Returns zero if successful or error if not.
3012 * This routine transitions the device to the SDEV_RUNNING state
3013 * or to one of the offline states (which must be a legal transition)
3014 * allowing the midlayer to goose the queue for this device.
3017 scsi_internal_device_unblock(struct scsi_device
*sdev
,
3018 enum scsi_device_state new_state
)
3020 struct request_queue
*q
= sdev
->request_queue
;
3021 unsigned long flags
;
3024 * Try to transition the scsi device to SDEV_RUNNING or one of the
3025 * offlined states and goose the device queue if successful.
3027 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
3028 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
3029 sdev
->sdev_state
= new_state
;
3030 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
3031 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3032 new_state
== SDEV_OFFLINE
)
3033 sdev
->sdev_state
= new_state
;
3035 sdev
->sdev_state
= SDEV_CREATED
;
3036 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
3037 sdev
->sdev_state
!= SDEV_OFFLINE
)
3041 blk_mq_start_stopped_hw_queues(q
, false);
3043 spin_lock_irqsave(q
->queue_lock
, flags
);
3045 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3050 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
3053 device_block(struct scsi_device
*sdev
, void *data
)
3055 scsi_internal_device_block(sdev
);
3059 target_block(struct device
*dev
, void *data
)
3061 if (scsi_is_target_device(dev
))
3062 starget_for_each_device(to_scsi_target(dev
), NULL
,
3068 scsi_target_block(struct device
*dev
)
3070 if (scsi_is_target_device(dev
))
3071 starget_for_each_device(to_scsi_target(dev
), NULL
,
3074 device_for_each_child(dev
, NULL
, target_block
);
3076 EXPORT_SYMBOL_GPL(scsi_target_block
);
3079 device_unblock(struct scsi_device
*sdev
, void *data
)
3081 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3085 target_unblock(struct device
*dev
, void *data
)
3087 if (scsi_is_target_device(dev
))
3088 starget_for_each_device(to_scsi_target(dev
), data
,
3094 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3096 if (scsi_is_target_device(dev
))
3097 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3100 device_for_each_child(dev
, &new_state
, target_unblock
);
3102 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3105 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3106 * @sgl: scatter-gather list
3107 * @sg_count: number of segments in sg
3108 * @offset: offset in bytes into sg, on return offset into the mapped area
3109 * @len: bytes to map, on return number of bytes mapped
3111 * Returns virtual address of the start of the mapped page
3113 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3114 size_t *offset
, size_t *len
)
3117 size_t sg_len
= 0, len_complete
= 0;
3118 struct scatterlist
*sg
;
3121 WARN_ON(!irqs_disabled());
3123 for_each_sg(sgl
, sg
, sg_count
, i
) {
3124 len_complete
= sg_len
; /* Complete sg-entries */
3125 sg_len
+= sg
->length
;
3126 if (sg_len
> *offset
)
3130 if (unlikely(i
== sg_count
)) {
3131 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3133 __func__
, sg_len
, *offset
, sg_count
);
3138 /* Offset starting from the beginning of first page in this sg-entry */
3139 *offset
= *offset
- len_complete
+ sg
->offset
;
3141 /* Assumption: contiguous pages can be accessed as "page + i" */
3142 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3143 *offset
&= ~PAGE_MASK
;
3145 /* Bytes in this sg-entry from *offset to the end of the page */
3146 sg_len
= PAGE_SIZE
- *offset
;
3150 return kmap_atomic(page
);
3152 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3155 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3156 * @virt: virtual address to be unmapped
3158 void scsi_kunmap_atomic_sg(void *virt
)
3160 kunmap_atomic(virt
);
3162 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3164 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3166 atomic_inc(&sdev
->disk_events_disable_depth
);
3168 EXPORT_SYMBOL(sdev_disable_disk_events
);
3170 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3172 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3174 atomic_dec(&sdev
->disk_events_disable_depth
);
3176 EXPORT_SYMBOL(sdev_enable_disk_events
);
3179 * scsi_vpd_lun_id - return a unique device identification
3180 * @sdev: SCSI device
3181 * @id: buffer for the identification
3182 * @id_len: length of the buffer
3184 * Copies a unique device identification into @id based
3185 * on the information in the VPD page 0x83 of the device.
3186 * The string will be formatted as a SCSI name string.
3188 * Returns the length of the identification or error on failure.
3189 * If the identifier is longer than the supplied buffer the actual
3190 * identifier length is returned and the buffer is not zero-padded.
3192 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3194 u8 cur_id_type
= 0xff;
3196 unsigned char *d
, *cur_id_str
;
3197 unsigned char __rcu
*vpd_pg83
;
3198 int id_size
= -EINVAL
;
3201 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3208 * Look for the correct descriptor.
3209 * Order of preference for lun descriptor:
3210 * - SCSI name string
3211 * - NAA IEEE Registered Extended
3212 * - EUI-64 based 16-byte
3213 * - EUI-64 based 12-byte
3214 * - NAA IEEE Registered
3215 * - NAA IEEE Extended
3217 * as longer descriptors reduce the likelyhood
3218 * of identification clashes.
3221 /* The id string must be at least 20 bytes + terminating NULL byte */
3227 memset(id
, 0, id_len
);
3229 while (d
< vpd_pg83
+ sdev
->vpd_pg83_len
) {
3230 /* Skip designators not referring to the LUN */
3231 if ((d
[1] & 0x30) != 0x00)
3234 switch (d
[1] & 0xf) {
3237 if (cur_id_size
> d
[3])
3239 /* Prefer anything */
3240 if (cur_id_type
> 0x01 && cur_id_type
!= 0xff)
3243 if (cur_id_size
+ 4 > id_len
)
3244 cur_id_size
= id_len
- 4;
3246 cur_id_type
= d
[1] & 0xf;
3247 id_size
= snprintf(id
, id_len
, "t10.%*pE",
3248 cur_id_size
, cur_id_str
);
3252 if (cur_id_size
> d
[3])
3254 /* Prefer NAA IEEE Registered Extended */
3255 if (cur_id_type
== 0x3 &&
3256 cur_id_size
== d
[3])
3260 cur_id_type
= d
[1] & 0xf;
3261 switch (cur_id_size
) {
3263 id_size
= snprintf(id
, id_len
,
3268 id_size
= snprintf(id
, id_len
,
3273 id_size
= snprintf(id
, id_len
,
3284 if (cur_id_size
> d
[3])
3288 cur_id_type
= d
[1] & 0xf;
3289 switch (cur_id_size
) {
3291 id_size
= snprintf(id
, id_len
,
3296 id_size
= snprintf(id
, id_len
,
3306 /* SCSI name string */
3307 if (cur_id_size
+ 4 > d
[3])
3309 /* Prefer others for truncated descriptor */
3310 if (cur_id_size
&& d
[3] > id_len
)
3312 cur_id_size
= id_size
= d
[3];
3314 cur_id_type
= d
[1] & 0xf;
3315 if (cur_id_size
>= id_len
)
3316 cur_id_size
= id_len
- 1;
3317 memcpy(id
, cur_id_str
, cur_id_size
);
3318 /* Decrease priority for truncated descriptor */
3319 if (cur_id_size
!= id_size
)
3332 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3335 * scsi_vpd_tpg_id - return a target port group identifier
3336 * @sdev: SCSI device
3338 * Returns the Target Port Group identifier from the information
3339 * froom VPD page 0x83 of the device.
3341 * Returns the identifier or error on failure.
3343 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3346 unsigned char __rcu
*vpd_pg83
;
3347 int group_id
= -EAGAIN
, rel_port
= -1;
3350 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3356 d
= sdev
->vpd_pg83
+ 4;
3357 while (d
< sdev
->vpd_pg83
+ sdev
->vpd_pg83_len
) {
3358 switch (d
[1] & 0xf) {
3360 /* Relative target port */
3361 rel_port
= get_unaligned_be16(&d
[6]);
3364 /* Target port group */
3365 group_id
= get_unaligned_be16(&d
[6]);
3374 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3379 EXPORT_SYMBOL(scsi_vpd_tpg_id
);