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 struct scsi_request
*rq
;
223 int ret
= DRIVER_ERROR
<< 24;
225 req
= blk_get_request(sdev
->request_queue
,
226 data_direction
== DMA_TO_DEVICE
?
227 REQ_OP_SCSI_OUT
: REQ_OP_SCSI_IN
, __GFP_RECLAIM
);
233 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
234 buffer
, bufflen
, __GFP_RECLAIM
))
237 rq
->cmd_len
= COMMAND_SIZE(cmd
[0]);
238 memcpy(rq
->cmd
, cmd
, rq
->cmd_len
);
239 req
->retries
= retries
;
240 req
->timeout
= timeout
;
241 req
->cmd_flags
|= flags
;
242 req
->rq_flags
|= rq_flags
| RQF_QUIET
| RQF_PREEMPT
;
245 * head injection *required* here otherwise quiesce won't work
247 blk_execute_rq(req
->q
, NULL
, req
, 1);
250 * Some devices (USB mass-storage in particular) may transfer
251 * garbage data together with a residue indicating that the data
252 * is invalid. Prevent the garbage from being misinterpreted
253 * and prevent security leaks by zeroing out the excess data.
255 if (unlikely(rq
->resid_len
> 0 && rq
->resid_len
<= bufflen
))
256 memset(buffer
+ (bufflen
- rq
->resid_len
), 0, rq
->resid_len
);
259 *resid
= rq
->resid_len
;
260 if (sense
&& rq
->sense_len
)
261 memcpy(sense
, rq
->sense
, SCSI_SENSE_BUFFERSIZE
);
264 blk_put_request(req
);
270 * scsi_execute - insert request and wait for the result
273 * @data_direction: data direction
274 * @buffer: data buffer
275 * @bufflen: len of buffer
276 * @sense: optional sense buffer
277 * @timeout: request timeout in seconds
278 * @retries: number of times to retry request
279 * @flags: or into request flags;
280 * @resid: optional residual length
282 * returns the req->errors value which is the scsi_cmnd result
285 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
286 int data_direction
, void *buffer
, unsigned bufflen
,
287 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
290 return __scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
, sense
,
291 timeout
, retries
, flags
, 0, resid
);
293 EXPORT_SYMBOL(scsi_execute
);
295 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
296 int data_direction
, void *buffer
, unsigned bufflen
,
297 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
298 int *resid
, u64 flags
, req_flags_t rq_flags
)
304 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
306 return DRIVER_ERROR
<< 24;
308 result
= __scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
309 sense
, timeout
, retries
, flags
, rq_flags
, resid
);
311 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
316 EXPORT_SYMBOL(scsi_execute_req_flags
);
319 * Function: scsi_init_cmd_errh()
321 * Purpose: Initialize cmd fields related to error handling.
323 * Arguments: cmd - command that is ready to be queued.
325 * Notes: This function has the job of initializing a number of
326 * fields related to error handling. Typically this will
327 * be called once for each command, as required.
329 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
331 cmd
->serial_number
= 0;
332 scsi_set_resid(cmd
, 0);
333 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
334 if (cmd
->cmd_len
== 0)
335 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
338 void scsi_device_unbusy(struct scsi_device
*sdev
)
340 struct Scsi_Host
*shost
= sdev
->host
;
341 struct scsi_target
*starget
= scsi_target(sdev
);
344 atomic_dec(&shost
->host_busy
);
345 if (starget
->can_queue
> 0)
346 atomic_dec(&starget
->target_busy
);
348 if (unlikely(scsi_host_in_recovery(shost
) &&
349 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
350 spin_lock_irqsave(shost
->host_lock
, flags
);
351 scsi_eh_wakeup(shost
);
352 spin_unlock_irqrestore(shost
->host_lock
, flags
);
355 atomic_dec(&sdev
->device_busy
);
358 static void scsi_kick_queue(struct request_queue
*q
)
361 blk_mq_start_hw_queues(q
);
367 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
368 * and call blk_run_queue for all the scsi_devices on the target -
369 * including current_sdev first.
371 * Called with *no* scsi locks held.
373 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
375 struct Scsi_Host
*shost
= current_sdev
->host
;
376 struct scsi_device
*sdev
, *tmp
;
377 struct scsi_target
*starget
= scsi_target(current_sdev
);
380 spin_lock_irqsave(shost
->host_lock
, flags
);
381 starget
->starget_sdev_user
= NULL
;
382 spin_unlock_irqrestore(shost
->host_lock
, flags
);
385 * Call blk_run_queue for all LUNs on the target, starting with
386 * current_sdev. We race with others (to set starget_sdev_user),
387 * but in most cases, we will be first. Ideally, each LU on the
388 * target would get some limited time or requests on the target.
390 scsi_kick_queue(current_sdev
->request_queue
);
392 spin_lock_irqsave(shost
->host_lock
, flags
);
393 if (starget
->starget_sdev_user
)
395 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
396 same_target_siblings
) {
397 if (sdev
== current_sdev
)
399 if (scsi_device_get(sdev
))
402 spin_unlock_irqrestore(shost
->host_lock
, flags
);
403 scsi_kick_queue(sdev
->request_queue
);
404 spin_lock_irqsave(shost
->host_lock
, flags
);
406 scsi_device_put(sdev
);
409 spin_unlock_irqrestore(shost
->host_lock
, flags
);
412 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
414 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
416 if (atomic_read(&sdev
->device_blocked
) > 0)
421 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
423 if (starget
->can_queue
> 0) {
424 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
426 if (atomic_read(&starget
->target_blocked
) > 0)
432 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
434 if (shost
->can_queue
> 0 &&
435 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
437 if (atomic_read(&shost
->host_blocked
) > 0)
439 if (shost
->host_self_blocked
)
444 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
446 LIST_HEAD(starved_list
);
447 struct scsi_device
*sdev
;
450 spin_lock_irqsave(shost
->host_lock
, flags
);
451 list_splice_init(&shost
->starved_list
, &starved_list
);
453 while (!list_empty(&starved_list
)) {
454 struct request_queue
*slq
;
457 * As long as shost is accepting commands and we have
458 * starved queues, call blk_run_queue. scsi_request_fn
459 * drops the queue_lock and can add us back to the
462 * host_lock protects the starved_list and starved_entry.
463 * scsi_request_fn must get the host_lock before checking
464 * or modifying starved_list or starved_entry.
466 if (scsi_host_is_busy(shost
))
469 sdev
= list_entry(starved_list
.next
,
470 struct scsi_device
, starved_entry
);
471 list_del_init(&sdev
->starved_entry
);
472 if (scsi_target_is_busy(scsi_target(sdev
))) {
473 list_move_tail(&sdev
->starved_entry
,
474 &shost
->starved_list
);
479 * Once we drop the host lock, a racing scsi_remove_device()
480 * call may remove the sdev from the starved list and destroy
481 * it and the queue. Mitigate by taking a reference to the
482 * queue and never touching the sdev again after we drop the
483 * host lock. Note: if __scsi_remove_device() invokes
484 * blk_cleanup_queue() before the queue is run from this
485 * function then blk_run_queue() will return immediately since
486 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
488 slq
= sdev
->request_queue
;
489 if (!blk_get_queue(slq
))
491 spin_unlock_irqrestore(shost
->host_lock
, flags
);
493 scsi_kick_queue(slq
);
496 spin_lock_irqsave(shost
->host_lock
, flags
);
498 /* put any unprocessed entries back */
499 list_splice(&starved_list
, &shost
->starved_list
);
500 spin_unlock_irqrestore(shost
->host_lock
, flags
);
504 * Function: scsi_run_queue()
506 * Purpose: Select a proper request queue to serve next
508 * Arguments: q - last request's queue
512 * Notes: The previous command was completely finished, start
513 * a new one if possible.
515 static void scsi_run_queue(struct request_queue
*q
)
517 struct scsi_device
*sdev
= q
->queuedata
;
519 if (scsi_target(sdev
)->single_lun
)
520 scsi_single_lun_run(sdev
);
521 if (!list_empty(&sdev
->host
->starved_list
))
522 scsi_starved_list_run(sdev
->host
);
525 blk_mq_start_stopped_hw_queues(q
, false);
530 void scsi_requeue_run_queue(struct work_struct
*work
)
532 struct scsi_device
*sdev
;
533 struct request_queue
*q
;
535 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
536 q
= sdev
->request_queue
;
541 * Function: scsi_requeue_command()
543 * Purpose: Handle post-processing of completed commands.
545 * Arguments: q - queue to operate on
546 * cmd - command that may need to be requeued.
550 * Notes: After command completion, there may be blocks left
551 * over which weren't finished by the previous command
552 * this can be for a number of reasons - the main one is
553 * I/O errors in the middle of the request, in which case
554 * we need to request the blocks that come after the bad
556 * Notes: Upon return, cmd is a stale pointer.
558 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
560 struct scsi_device
*sdev
= cmd
->device
;
561 struct request
*req
= cmd
->request
;
564 spin_lock_irqsave(q
->queue_lock
, flags
);
565 blk_unprep_request(req
);
567 scsi_put_command(cmd
);
568 blk_requeue_request(q
, req
);
569 spin_unlock_irqrestore(q
->queue_lock
, flags
);
573 put_device(&sdev
->sdev_gendev
);
576 void scsi_run_host_queues(struct Scsi_Host
*shost
)
578 struct scsi_device
*sdev
;
580 shost_for_each_device(sdev
, shost
)
581 scsi_run_queue(sdev
->request_queue
);
584 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
586 if (!blk_rq_is_passthrough(cmd
->request
)) {
587 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
589 if (drv
->uninit_command
)
590 drv
->uninit_command(cmd
);
594 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
596 struct scsi_data_buffer
*sdb
;
598 if (cmd
->sdb
.table
.nents
)
599 sg_free_table_chained(&cmd
->sdb
.table
, true);
600 if (cmd
->request
->next_rq
) {
601 sdb
= cmd
->request
->next_rq
->special
;
603 sg_free_table_chained(&sdb
->table
, true);
605 if (scsi_prot_sg_count(cmd
))
606 sg_free_table_chained(&cmd
->prot_sdb
->table
, true);
609 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
611 struct scsi_device
*sdev
= cmd
->device
;
612 struct Scsi_Host
*shost
= sdev
->host
;
615 scsi_mq_free_sgtables(cmd
);
616 scsi_uninit_cmd(cmd
);
618 if (shost
->use_cmd_list
) {
619 BUG_ON(list_empty(&cmd
->list
));
620 spin_lock_irqsave(&sdev
->list_lock
, flags
);
621 list_del_init(&cmd
->list
);
622 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
627 * Function: scsi_release_buffers()
629 * Purpose: Free resources allocate for a scsi_command.
631 * Arguments: cmd - command that we are bailing.
633 * Lock status: Assumed that no lock is held upon entry.
637 * Notes: In the event that an upper level driver rejects a
638 * command, we must release resources allocated during
639 * the __init_io() function. Primarily this would involve
640 * the scatter-gather table.
642 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
644 if (cmd
->sdb
.table
.nents
)
645 sg_free_table_chained(&cmd
->sdb
.table
, false);
647 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
649 if (scsi_prot_sg_count(cmd
))
650 sg_free_table_chained(&cmd
->prot_sdb
->table
, false);
653 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
655 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
657 sg_free_table_chained(&bidi_sdb
->table
, false);
658 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
659 cmd
->request
->next_rq
->special
= NULL
;
662 static bool scsi_end_request(struct request
*req
, int error
,
663 unsigned int bytes
, unsigned int bidi_bytes
)
665 struct scsi_cmnd
*cmd
= req
->special
;
666 struct scsi_device
*sdev
= cmd
->device
;
667 struct request_queue
*q
= sdev
->request_queue
;
669 if (blk_update_request(req
, error
, bytes
))
672 /* Bidi request must be completed as a whole */
673 if (unlikely(bidi_bytes
) &&
674 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
677 if (blk_queue_add_random(q
))
678 add_disk_randomness(req
->rq_disk
);
682 * In the MQ case the command gets freed by __blk_mq_end_request,
683 * so we have to do all cleanup that depends on it earlier.
685 * We also can't kick the queues from irq context, so we
686 * will have to defer it to a workqueue.
688 scsi_mq_uninit_cmd(cmd
);
690 __blk_mq_end_request(req
, error
);
692 if (scsi_target(sdev
)->single_lun
||
693 !list_empty(&sdev
->host
->starved_list
))
694 kblockd_schedule_work(&sdev
->requeue_work
);
696 blk_mq_start_stopped_hw_queues(q
, true);
701 scsi_release_bidi_buffers(cmd
);
702 scsi_release_buffers(cmd
);
703 scsi_put_command(cmd
);
705 spin_lock_irqsave(q
->queue_lock
, flags
);
706 blk_finish_request(req
, error
);
707 spin_unlock_irqrestore(q
->queue_lock
, flags
);
712 put_device(&sdev
->sdev_gendev
);
717 * __scsi_error_from_host_byte - translate SCSI error code into errno
718 * @cmd: SCSI command (unused)
719 * @result: scsi error code
721 * Translate SCSI error code into standard UNIX errno.
723 * -ENOLINK temporary transport failure
724 * -EREMOTEIO permanent target failure, do not retry
725 * -EBADE permanent nexus failure, retry on other path
726 * -ENOSPC No write space available
727 * -ENODATA Medium error
728 * -EIO unspecified I/O error
730 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
734 switch(host_byte(result
)) {
735 case DID_TRANSPORT_FAILFAST
:
738 case DID_TARGET_FAILURE
:
739 set_host_byte(cmd
, DID_OK
);
742 case DID_NEXUS_FAILURE
:
743 set_host_byte(cmd
, DID_OK
);
746 case DID_ALLOC_FAILURE
:
747 set_host_byte(cmd
, DID_OK
);
750 case DID_MEDIUM_ERROR
:
751 set_host_byte(cmd
, DID_OK
);
763 * Function: scsi_io_completion()
765 * Purpose: Completion processing for block device I/O requests.
767 * Arguments: cmd - command that is finished.
769 * Lock status: Assumed that no lock is held upon entry.
773 * Notes: We will finish off the specified number of sectors. If we
774 * are done, the command block will be released and the queue
775 * function will be goosed. If we are not done then we have to
776 * figure out what to do next:
778 * a) We can call scsi_requeue_command(). The request
779 * will be unprepared and put back on the queue. Then
780 * a new command will be created for it. This should
781 * be used if we made forward progress, or if we want
782 * to switch from READ(10) to READ(6) for example.
784 * b) We can call __scsi_queue_insert(). The request will
785 * be put back on the queue and retried using the same
786 * command as before, possibly after a delay.
788 * c) We can call scsi_end_request() with -EIO to fail
789 * the remainder of the request.
791 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
793 int result
= cmd
->result
;
794 struct request_queue
*q
= cmd
->device
->request_queue
;
795 struct request
*req
= cmd
->request
;
797 struct scsi_sense_hdr sshdr
;
798 bool sense_valid
= false;
799 int sense_deferred
= 0, level
= 0;
800 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
801 ACTION_DELAYED_RETRY
} action
;
802 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
805 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
807 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
810 if (blk_rq_is_passthrough(req
)) {
814 * SG_IO wants current and deferred errors
816 scsi_req(req
)->sense_len
=
817 min(8 + cmd
->sense_buffer
[7],
818 SCSI_SENSE_BUFFERSIZE
);
821 error
= __scsi_error_from_host_byte(cmd
, result
);
824 * __scsi_error_from_host_byte may have reset the host_byte
826 req
->errors
= cmd
->result
;
828 scsi_req(req
)->resid_len
= scsi_get_resid(cmd
);
830 if (scsi_bidi_cmnd(cmd
)) {
832 * Bidi commands Must be complete as a whole,
833 * both sides at once.
835 scsi_req(req
->next_rq
)->resid_len
= scsi_in(cmd
)->resid
;
836 if (scsi_end_request(req
, 0, blk_rq_bytes(req
),
837 blk_rq_bytes(req
->next_rq
)))
841 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
843 * Flush commands do not transfers any data, and thus 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 as
863 * success, so fiddle the result code here. For passthrough requests
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 /* for passthrough error may be set */
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 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq
)))
1095 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1099 if (blk_bidi_rq(rq
)) {
1100 if (!rq
->q
->mq_ops
) {
1101 struct scsi_data_buffer
*bidi_sdb
=
1102 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1104 error
= BLKPREP_DEFER
;
1108 rq
->next_rq
->special
= bidi_sdb
;
1111 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1116 if (blk_integrity_rq(rq
)) {
1117 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1120 if (prot_sdb
== NULL
) {
1122 * This can happen if someone (e.g. multipath)
1123 * queues a command to a device on an adapter
1124 * that does not support DIX.
1127 error
= BLKPREP_KILL
;
1131 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1133 if (sg_alloc_table_chained(&prot_sdb
->table
, ivecs
,
1134 prot_sdb
->table
.sgl
)) {
1135 error
= BLKPREP_DEFER
;
1139 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1140 prot_sdb
->table
.sgl
);
1141 BUG_ON(unlikely(count
> ivecs
));
1142 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1144 cmd
->prot_sdb
= prot_sdb
;
1145 cmd
->prot_sdb
->table
.nents
= count
;
1151 scsi_mq_free_sgtables(cmd
);
1153 scsi_release_buffers(cmd
);
1154 cmd
->request
->special
= NULL
;
1155 scsi_put_command(cmd
);
1156 put_device(&sdev
->sdev_gendev
);
1160 EXPORT_SYMBOL(scsi_init_io
);
1162 void scsi_init_command(struct scsi_device
*dev
, struct scsi_cmnd
*cmd
)
1164 void *buf
= cmd
->sense_buffer
;
1165 void *prot
= cmd
->prot_sdb
;
1166 unsigned long flags
;
1168 /* zero out the cmd, except for the embedded scsi_request */
1169 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1170 sizeof(*cmd
) - sizeof(cmd
->req
) + dev
->host
->hostt
->cmd_size
);
1173 cmd
->sense_buffer
= buf
;
1174 cmd
->prot_sdb
= prot
;
1175 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1176 cmd
->jiffies_at_alloc
= jiffies
;
1178 spin_lock_irqsave(&dev
->list_lock
, flags
);
1179 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
1180 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
1183 static int scsi_setup_scsi_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1185 struct scsi_cmnd
*cmd
= req
->special
;
1188 * Passthrough requests may transfer data, in which case they must
1189 * a bio attached to them. Or they might contain a SCSI command
1190 * that does not transfer data, in which case they may optionally
1191 * submit a request without an attached bio.
1194 int ret
= scsi_init_io(cmd
);
1198 BUG_ON(blk_rq_bytes(req
));
1200 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1203 cmd
->cmd_len
= scsi_req(req
)->cmd_len
;
1204 cmd
->cmnd
= scsi_req(req
)->cmd
;
1205 cmd
->transfersize
= blk_rq_bytes(req
);
1206 cmd
->allowed
= req
->retries
;
1211 * Setup a normal block command. These are simple request from filesystems
1212 * that still need to be translated to SCSI CDBs from the ULD.
1214 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1216 struct scsi_cmnd
*cmd
= req
->special
;
1218 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1219 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1220 if (ret
!= BLKPREP_OK
)
1224 cmd
->cmnd
= scsi_req(req
)->cmd
= scsi_req(req
)->__cmd
;
1225 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1226 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1229 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1231 struct scsi_cmnd
*cmd
= req
->special
;
1233 if (!blk_rq_bytes(req
))
1234 cmd
->sc_data_direction
= DMA_NONE
;
1235 else if (rq_data_dir(req
) == WRITE
)
1236 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1238 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1240 if (blk_rq_is_scsi(req
))
1241 return scsi_setup_scsi_cmnd(sdev
, req
);
1243 return scsi_setup_fs_cmnd(sdev
, req
);
1247 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1249 int ret
= BLKPREP_OK
;
1252 * If the device is not in running state we will reject some
1255 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1256 switch (sdev
->sdev_state
) {
1258 case SDEV_TRANSPORT_OFFLINE
:
1260 * If the device is offline we refuse to process any
1261 * commands. The device must be brought online
1262 * before trying any recovery commands.
1264 sdev_printk(KERN_ERR
, sdev
,
1265 "rejecting I/O to offline device\n");
1270 * If the device is fully deleted, we refuse to
1271 * process any commands as well.
1273 sdev_printk(KERN_ERR
, sdev
,
1274 "rejecting I/O to dead device\n");
1278 case SDEV_CREATED_BLOCK
:
1279 ret
= BLKPREP_DEFER
;
1283 * If the devices is blocked we defer normal commands.
1285 if (!(req
->rq_flags
& RQF_PREEMPT
))
1286 ret
= BLKPREP_DEFER
;
1290 * For any other not fully online state we only allow
1291 * special commands. In particular any user initiated
1292 * command is not allowed.
1294 if (!(req
->rq_flags
& RQF_PREEMPT
))
1303 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1305 struct scsi_device
*sdev
= q
->queuedata
;
1309 case BLKPREP_INVALID
:
1310 req
->errors
= DID_NO_CONNECT
<< 16;
1311 /* release the command and kill it */
1313 struct scsi_cmnd
*cmd
= req
->special
;
1314 scsi_release_buffers(cmd
);
1315 scsi_put_command(cmd
);
1316 put_device(&sdev
->sdev_gendev
);
1317 req
->special
= NULL
;
1322 * If we defer, the blk_peek_request() returns NULL, but the
1323 * queue must be restarted, so we schedule a callback to happen
1326 if (atomic_read(&sdev
->device_busy
) == 0)
1327 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1330 req
->rq_flags
|= RQF_DONTPREP
;
1336 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1338 struct scsi_device
*sdev
= q
->queuedata
;
1339 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1342 ret
= scsi_prep_state_check(sdev
, req
);
1343 if (ret
!= BLKPREP_OK
)
1346 if (!req
->special
) {
1347 /* Bail if we can't get a reference to the device */
1348 if (unlikely(!get_device(&sdev
->sdev_gendev
))) {
1349 ret
= BLKPREP_DEFER
;
1353 scsi_init_command(sdev
, cmd
);
1357 cmd
->tag
= req
->tag
;
1359 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1361 ret
= scsi_setup_cmnd(sdev
, req
);
1363 return scsi_prep_return(q
, req
, ret
);
1366 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1368 scsi_uninit_cmd(req
->special
);
1372 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1375 * Called with the queue_lock held.
1377 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1378 struct scsi_device
*sdev
)
1382 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1383 if (atomic_read(&sdev
->device_blocked
)) {
1388 * unblock after device_blocked iterates to zero
1390 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1392 * For the MQ case we take care of this in the caller.
1395 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1398 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1399 "unblocking device at zero depth\n"));
1402 if (busy
>= sdev
->queue_depth
)
1407 atomic_dec(&sdev
->device_busy
);
1412 * scsi_target_queue_ready: checks if there we can send commands to target
1413 * @sdev: scsi device on starget to check.
1415 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1416 struct scsi_device
*sdev
)
1418 struct scsi_target
*starget
= scsi_target(sdev
);
1421 if (starget
->single_lun
) {
1422 spin_lock_irq(shost
->host_lock
);
1423 if (starget
->starget_sdev_user
&&
1424 starget
->starget_sdev_user
!= sdev
) {
1425 spin_unlock_irq(shost
->host_lock
);
1428 starget
->starget_sdev_user
= sdev
;
1429 spin_unlock_irq(shost
->host_lock
);
1432 if (starget
->can_queue
<= 0)
1435 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1436 if (atomic_read(&starget
->target_blocked
) > 0) {
1441 * unblock after target_blocked iterates to zero
1443 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1446 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1447 "unblocking target at zero depth\n"));
1450 if (busy
>= starget
->can_queue
)
1456 spin_lock_irq(shost
->host_lock
);
1457 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1458 spin_unlock_irq(shost
->host_lock
);
1460 if (starget
->can_queue
> 0)
1461 atomic_dec(&starget
->target_busy
);
1466 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1467 * return 0. We must end up running the queue again whenever 0 is
1468 * returned, else IO can hang.
1470 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1471 struct Scsi_Host
*shost
,
1472 struct scsi_device
*sdev
)
1476 if (scsi_host_in_recovery(shost
))
1479 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1480 if (atomic_read(&shost
->host_blocked
) > 0) {
1485 * unblock after host_blocked iterates to zero
1487 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1491 shost_printk(KERN_INFO
, shost
,
1492 "unblocking host at zero depth\n"));
1495 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1497 if (shost
->host_self_blocked
)
1500 /* We're OK to process the command, so we can't be starved */
1501 if (!list_empty(&sdev
->starved_entry
)) {
1502 spin_lock_irq(shost
->host_lock
);
1503 if (!list_empty(&sdev
->starved_entry
))
1504 list_del_init(&sdev
->starved_entry
);
1505 spin_unlock_irq(shost
->host_lock
);
1511 spin_lock_irq(shost
->host_lock
);
1512 if (list_empty(&sdev
->starved_entry
))
1513 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1514 spin_unlock_irq(shost
->host_lock
);
1516 atomic_dec(&shost
->host_busy
);
1521 * Busy state exporting function for request stacking drivers.
1523 * For efficiency, no lock is taken to check the busy state of
1524 * shost/starget/sdev, since the returned value is not guaranteed and
1525 * may be changed after request stacking drivers call the function,
1526 * regardless of taking lock or not.
1528 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1529 * needs to return 'not busy'. Otherwise, request stacking drivers
1530 * may hold requests forever.
1532 static int scsi_lld_busy(struct request_queue
*q
)
1534 struct scsi_device
*sdev
= q
->queuedata
;
1535 struct Scsi_Host
*shost
;
1537 if (blk_queue_dying(q
))
1543 * Ignore host/starget busy state.
1544 * Since block layer does not have a concept of fairness across
1545 * multiple queues, congestion of host/starget needs to be handled
1548 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1555 * Kill a request for a dead device
1557 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1559 struct scsi_cmnd
*cmd
= req
->special
;
1560 struct scsi_device
*sdev
;
1561 struct scsi_target
*starget
;
1562 struct Scsi_Host
*shost
;
1564 blk_start_request(req
);
1566 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1569 starget
= scsi_target(sdev
);
1571 scsi_init_cmd_errh(cmd
);
1572 cmd
->result
= DID_NO_CONNECT
<< 16;
1573 atomic_inc(&cmd
->device
->iorequest_cnt
);
1576 * SCSI request completion path will do scsi_device_unbusy(),
1577 * bump busy counts. To bump the counters, we need to dance
1578 * with the locks as normal issue path does.
1580 atomic_inc(&sdev
->device_busy
);
1581 atomic_inc(&shost
->host_busy
);
1582 if (starget
->can_queue
> 0)
1583 atomic_inc(&starget
->target_busy
);
1585 blk_complete_request(req
);
1588 static void scsi_softirq_done(struct request
*rq
)
1590 struct scsi_cmnd
*cmd
= rq
->special
;
1591 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1594 INIT_LIST_HEAD(&cmd
->eh_entry
);
1596 atomic_inc(&cmd
->device
->iodone_cnt
);
1598 atomic_inc(&cmd
->device
->ioerr_cnt
);
1600 disposition
= scsi_decide_disposition(cmd
);
1601 if (disposition
!= SUCCESS
&&
1602 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1603 sdev_printk(KERN_ERR
, cmd
->device
,
1604 "timing out command, waited %lus\n",
1606 disposition
= SUCCESS
;
1609 scsi_log_completion(cmd
, disposition
);
1611 switch (disposition
) {
1613 scsi_finish_command(cmd
);
1616 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1618 case ADD_TO_MLQUEUE
:
1619 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1622 if (!scsi_eh_scmd_add(cmd
, 0))
1623 scsi_finish_command(cmd
);
1628 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1629 * @cmd: command block we are dispatching.
1631 * Return: nonzero return request was rejected and device's queue needs to be
1634 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1636 struct Scsi_Host
*host
= cmd
->device
->host
;
1639 atomic_inc(&cmd
->device
->iorequest_cnt
);
1641 /* check if the device is still usable */
1642 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1643 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1644 * returns an immediate error upwards, and signals
1645 * that the device is no longer present */
1646 cmd
->result
= DID_NO_CONNECT
<< 16;
1650 /* Check to see if the scsi lld made this device blocked. */
1651 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1653 * in blocked state, the command is just put back on
1654 * the device queue. The suspend state has already
1655 * blocked the queue so future requests should not
1656 * occur until the device transitions out of the
1659 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1660 "queuecommand : device blocked\n"));
1661 return SCSI_MLQUEUE_DEVICE_BUSY
;
1664 /* Store the LUN value in cmnd, if needed. */
1665 if (cmd
->device
->lun_in_cdb
)
1666 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1667 (cmd
->device
->lun
<< 5 & 0xe0);
1672 * Before we queue this command, check if the command
1673 * length exceeds what the host adapter can handle.
1675 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1676 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1677 "queuecommand : command too long. "
1678 "cdb_size=%d host->max_cmd_len=%d\n",
1679 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1680 cmd
->result
= (DID_ABORT
<< 16);
1684 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1685 cmd
->result
= (DID_NO_CONNECT
<< 16);
1690 trace_scsi_dispatch_cmd_start(cmd
);
1691 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1693 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1694 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1695 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1696 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1698 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1699 "queuecommand : request rejected\n"));
1704 cmd
->scsi_done(cmd
);
1709 * scsi_done - Invoke completion on finished SCSI command.
1710 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1711 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1713 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1714 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1715 * calls blk_complete_request() for further processing.
1717 * This function is interrupt context safe.
1719 static void scsi_done(struct scsi_cmnd
*cmd
)
1721 trace_scsi_dispatch_cmd_done(cmd
);
1722 blk_complete_request(cmd
->request
);
1726 * Function: scsi_request_fn()
1728 * Purpose: Main strategy routine for SCSI.
1730 * Arguments: q - Pointer to actual queue.
1734 * Lock status: IO request lock assumed to be held when called.
1736 static void scsi_request_fn(struct request_queue
*q
)
1737 __releases(q
->queue_lock
)
1738 __acquires(q
->queue_lock
)
1740 struct scsi_device
*sdev
= q
->queuedata
;
1741 struct Scsi_Host
*shost
;
1742 struct scsi_cmnd
*cmd
;
1743 struct request
*req
;
1746 * To start with, we keep looping until the queue is empty, or until
1747 * the host is no longer able to accept any more requests.
1753 * get next queueable request. We do this early to make sure
1754 * that the request is fully prepared even if we cannot
1757 req
= blk_peek_request(q
);
1761 if (unlikely(!scsi_device_online(sdev
))) {
1762 sdev_printk(KERN_ERR
, sdev
,
1763 "rejecting I/O to offline device\n");
1764 scsi_kill_request(req
, q
);
1768 if (!scsi_dev_queue_ready(q
, sdev
))
1772 * Remove the request from the request list.
1774 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1775 blk_start_request(req
);
1777 spin_unlock_irq(q
->queue_lock
);
1779 if (unlikely(cmd
== NULL
)) {
1780 printk(KERN_CRIT
"impossible request in %s.\n"
1781 "please mail a stack trace to "
1782 "linux-scsi@vger.kernel.org\n",
1784 blk_dump_rq_flags(req
, "foo");
1789 * We hit this when the driver is using a host wide
1790 * tag map. For device level tag maps the queue_depth check
1791 * in the device ready fn would prevent us from trying
1792 * to allocate a tag. Since the map is a shared host resource
1793 * we add the dev to the starved list so it eventually gets
1794 * a run when a tag is freed.
1796 if (blk_queue_tagged(q
) && !(req
->rq_flags
& RQF_QUEUED
)) {
1797 spin_lock_irq(shost
->host_lock
);
1798 if (list_empty(&sdev
->starved_entry
))
1799 list_add_tail(&sdev
->starved_entry
,
1800 &shost
->starved_list
);
1801 spin_unlock_irq(shost
->host_lock
);
1805 if (!scsi_target_queue_ready(shost
, sdev
))
1808 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1809 goto host_not_ready
;
1811 if (sdev
->simple_tags
)
1812 cmd
->flags
|= SCMD_TAGGED
;
1814 cmd
->flags
&= ~SCMD_TAGGED
;
1817 * Finally, initialize any error handling parameters, and set up
1818 * the timers for timeouts.
1820 scsi_init_cmd_errh(cmd
);
1823 * Dispatch the command to the low-level driver.
1825 cmd
->scsi_done
= scsi_done
;
1826 rtn
= scsi_dispatch_cmd(cmd
);
1828 scsi_queue_insert(cmd
, rtn
);
1829 spin_lock_irq(q
->queue_lock
);
1832 spin_lock_irq(q
->queue_lock
);
1838 if (scsi_target(sdev
)->can_queue
> 0)
1839 atomic_dec(&scsi_target(sdev
)->target_busy
);
1842 * lock q, handle tag, requeue req, and decrement device_busy. We
1843 * must return with queue_lock held.
1845 * Decrementing device_busy without checking it is OK, as all such
1846 * cases (host limits or settings) should run the queue at some
1849 spin_lock_irq(q
->queue_lock
);
1850 blk_requeue_request(q
, req
);
1851 atomic_dec(&sdev
->device_busy
);
1853 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1854 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1857 static inline int prep_to_mq(int ret
)
1861 return BLK_MQ_RQ_QUEUE_OK
;
1863 return BLK_MQ_RQ_QUEUE_BUSY
;
1865 return BLK_MQ_RQ_QUEUE_ERROR
;
1869 static int scsi_mq_prep_fn(struct request
*req
)
1871 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1872 struct scsi_device
*sdev
= req
->q
->queuedata
;
1873 struct Scsi_Host
*shost
= sdev
->host
;
1874 unsigned char *sense_buf
= cmd
->sense_buffer
;
1875 struct scatterlist
*sg
;
1877 /* zero out the cmd, except for the embedded scsi_request */
1878 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1879 sizeof(*cmd
) - sizeof(cmd
->req
));
1885 cmd
->sense_buffer
= sense_buf
;
1887 cmd
->tag
= req
->tag
;
1889 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1891 INIT_LIST_HEAD(&cmd
->list
);
1892 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1893 cmd
->jiffies_at_alloc
= jiffies
;
1895 if (shost
->use_cmd_list
) {
1896 spin_lock_irq(&sdev
->list_lock
);
1897 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1898 spin_unlock_irq(&sdev
->list_lock
);
1901 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1902 cmd
->sdb
.table
.sgl
= sg
;
1904 if (scsi_host_get_prot(shost
)) {
1905 cmd
->prot_sdb
= (void *)sg
+
1907 shost
->sg_tablesize
, SG_CHUNK_SIZE
) *
1908 sizeof(struct scatterlist
);
1909 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1911 cmd
->prot_sdb
->table
.sgl
=
1912 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1915 if (blk_bidi_rq(req
)) {
1916 struct request
*next_rq
= req
->next_rq
;
1917 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1919 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1920 bidi_sdb
->table
.sgl
=
1921 (struct scatterlist
*)(bidi_sdb
+ 1);
1923 next_rq
->special
= bidi_sdb
;
1926 blk_mq_start_request(req
);
1928 return scsi_setup_cmnd(sdev
, req
);
1931 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1933 trace_scsi_dispatch_cmd_done(cmd
);
1934 blk_mq_complete_request(cmd
->request
, cmd
->request
->errors
);
1937 static int scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1938 const struct blk_mq_queue_data
*bd
)
1940 struct request
*req
= bd
->rq
;
1941 struct request_queue
*q
= req
->q
;
1942 struct scsi_device
*sdev
= q
->queuedata
;
1943 struct Scsi_Host
*shost
= sdev
->host
;
1944 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1948 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1949 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1952 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1953 if (!get_device(&sdev
->sdev_gendev
))
1956 if (!scsi_dev_queue_ready(q
, sdev
))
1957 goto out_put_device
;
1958 if (!scsi_target_queue_ready(shost
, sdev
))
1959 goto out_dec_device_busy
;
1960 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1961 goto out_dec_target_busy
;
1963 if (!(req
->rq_flags
& RQF_DONTPREP
)) {
1964 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1965 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1966 goto out_dec_host_busy
;
1967 req
->rq_flags
|= RQF_DONTPREP
;
1969 blk_mq_start_request(req
);
1972 if (sdev
->simple_tags
)
1973 cmd
->flags
|= SCMD_TAGGED
;
1975 cmd
->flags
&= ~SCMD_TAGGED
;
1977 scsi_init_cmd_errh(cmd
);
1978 cmd
->scsi_done
= scsi_mq_done
;
1980 reason
= scsi_dispatch_cmd(cmd
);
1982 scsi_set_blocked(cmd
, reason
);
1983 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1984 goto out_dec_host_busy
;
1987 return BLK_MQ_RQ_QUEUE_OK
;
1990 atomic_dec(&shost
->host_busy
);
1991 out_dec_target_busy
:
1992 if (scsi_target(sdev
)->can_queue
> 0)
1993 atomic_dec(&scsi_target(sdev
)->target_busy
);
1994 out_dec_device_busy
:
1995 atomic_dec(&sdev
->device_busy
);
1997 put_device(&sdev
->sdev_gendev
);
2000 case BLK_MQ_RQ_QUEUE_BUSY
:
2001 if (atomic_read(&sdev
->device_busy
) == 0 &&
2002 !scsi_device_blocked(sdev
))
2003 blk_mq_delay_queue(hctx
, SCSI_QUEUE_DELAY
);
2005 case BLK_MQ_RQ_QUEUE_ERROR
:
2007 * Make sure to release all allocated ressources when
2008 * we hit an error, as we will never see this command
2011 if (req
->rq_flags
& RQF_DONTPREP
)
2012 scsi_mq_uninit_cmd(cmd
);
2020 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
2024 return BLK_EH_RESET_TIMER
;
2025 return scsi_times_out(req
);
2028 static int scsi_init_request(void *data
, struct request
*rq
,
2029 unsigned int hctx_idx
, unsigned int request_idx
,
2030 unsigned int numa_node
)
2032 struct Scsi_Host
*shost
= data
;
2033 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2036 scsi_alloc_sense_buffer(shost
, GFP_KERNEL
, numa_node
);
2037 if (!cmd
->sense_buffer
)
2039 cmd
->req
.sense
= cmd
->sense_buffer
;
2043 static void scsi_exit_request(void *data
, struct request
*rq
,
2044 unsigned int hctx_idx
, unsigned int request_idx
)
2046 struct Scsi_Host
*shost
= data
;
2047 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2049 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2052 static int scsi_map_queues(struct blk_mq_tag_set
*set
)
2054 struct Scsi_Host
*shost
= container_of(set
, struct Scsi_Host
, tag_set
);
2056 if (shost
->hostt
->map_queues
)
2057 return shost
->hostt
->map_queues(shost
);
2058 return blk_mq_map_queues(set
);
2061 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2063 struct device
*host_dev
;
2064 u64 bounce_limit
= 0xffffffff;
2066 if (shost
->unchecked_isa_dma
)
2067 return BLK_BOUNCE_ISA
;
2069 * Platforms with virtual-DMA translation
2070 * hardware have no practical limit.
2072 if (!PCI_DMA_BUS_IS_PHYS
)
2073 return BLK_BOUNCE_ANY
;
2075 host_dev
= scsi_get_device(shost
);
2076 if (host_dev
&& host_dev
->dma_mask
)
2077 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2079 return bounce_limit
;
2082 void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2084 struct device
*dev
= shost
->dma_dev
;
2087 * this limit is imposed by hardware restrictions
2089 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
2092 if (scsi_host_prot_dma(shost
)) {
2093 shost
->sg_prot_tablesize
=
2094 min_not_zero(shost
->sg_prot_tablesize
,
2095 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
2096 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
2097 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
2100 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
2101 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
2102 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
2103 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
2105 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2107 if (!shost
->use_clustering
)
2108 q
->limits
.cluster
= 0;
2111 * set a reasonable default alignment on word boundaries: the
2112 * host and device may alter it using
2113 * blk_queue_update_dma_alignment() later.
2115 blk_queue_dma_alignment(q
, 0x03);
2117 EXPORT_SYMBOL_GPL(__scsi_init_queue
);
2119 static int scsi_init_rq(struct request_queue
*q
, struct request
*rq
, gfp_t gfp
)
2121 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2122 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2124 memset(cmd
, 0, sizeof(*cmd
));
2126 cmd
->sense_buffer
= scsi_alloc_sense_buffer(shost
, gfp
, NUMA_NO_NODE
);
2127 if (!cmd
->sense_buffer
)
2129 cmd
->req
.sense
= cmd
->sense_buffer
;
2131 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
2132 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp
);
2134 goto fail_free_sense
;
2140 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2145 static void scsi_exit_rq(struct request_queue
*q
, struct request
*rq
)
2147 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2148 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2151 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
2152 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2155 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
2157 struct Scsi_Host
*shost
= sdev
->host
;
2158 struct request_queue
*q
;
2160 q
= blk_alloc_queue_node(GFP_KERNEL
, NUMA_NO_NODE
);
2163 q
->cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
2164 q
->rq_alloc_data
= shost
;
2165 q
->request_fn
= scsi_request_fn
;
2166 q
->init_rq_fn
= scsi_init_rq
;
2167 q
->exit_rq_fn
= scsi_exit_rq
;
2169 if (blk_init_allocated_queue(q
) < 0) {
2170 blk_cleanup_queue(q
);
2174 __scsi_init_queue(shost
, q
);
2175 blk_queue_prep_rq(q
, scsi_prep_fn
);
2176 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2177 blk_queue_softirq_done(q
, scsi_softirq_done
);
2178 blk_queue_rq_timed_out(q
, scsi_times_out
);
2179 blk_queue_lld_busy(q
, scsi_lld_busy
);
2183 static struct blk_mq_ops scsi_mq_ops
= {
2184 .queue_rq
= scsi_queue_rq
,
2185 .complete
= scsi_softirq_done
,
2186 .timeout
= scsi_timeout
,
2187 .init_request
= scsi_init_request
,
2188 .exit_request
= scsi_exit_request
,
2189 .map_queues
= scsi_map_queues
,
2192 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2194 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2195 if (IS_ERR(sdev
->request_queue
))
2198 sdev
->request_queue
->queuedata
= sdev
;
2199 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2200 return sdev
->request_queue
;
2203 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2205 unsigned int cmd_size
, sgl_size
, tbl_size
;
2207 tbl_size
= shost
->sg_tablesize
;
2208 if (tbl_size
> SG_CHUNK_SIZE
)
2209 tbl_size
= SG_CHUNK_SIZE
;
2210 sgl_size
= tbl_size
* sizeof(struct scatterlist
);
2211 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2212 if (scsi_host_get_prot(shost
))
2213 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2215 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2216 shost
->tag_set
.ops
= &scsi_mq_ops
;
2217 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2218 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2219 shost
->tag_set
.cmd_size
= cmd_size
;
2220 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2221 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2222 shost
->tag_set
.flags
|=
2223 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2224 shost
->tag_set
.driver_data
= shost
;
2226 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2229 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2231 blk_mq_free_tag_set(&shost
->tag_set
);
2235 * Function: scsi_block_requests()
2237 * Purpose: Utility function used by low-level drivers to prevent further
2238 * commands from being queued to the device.
2240 * Arguments: shost - Host in question
2244 * Lock status: No locks are assumed held.
2246 * Notes: There is no timer nor any other means by which the requests
2247 * get unblocked other than the low-level driver calling
2248 * scsi_unblock_requests().
2250 void scsi_block_requests(struct Scsi_Host
*shost
)
2252 shost
->host_self_blocked
= 1;
2254 EXPORT_SYMBOL(scsi_block_requests
);
2257 * Function: scsi_unblock_requests()
2259 * Purpose: Utility function used by low-level drivers to allow further
2260 * commands from being queued to the device.
2262 * Arguments: shost - Host in question
2266 * Lock status: No locks are assumed held.
2268 * Notes: There is no timer nor any other means by which the requests
2269 * get unblocked other than the low-level driver calling
2270 * scsi_unblock_requests().
2272 * This is done as an API function so that changes to the
2273 * internals of the scsi mid-layer won't require wholesale
2274 * changes to drivers that use this feature.
2276 void scsi_unblock_requests(struct Scsi_Host
*shost
)
2278 shost
->host_self_blocked
= 0;
2279 scsi_run_host_queues(shost
);
2281 EXPORT_SYMBOL(scsi_unblock_requests
);
2283 int __init
scsi_init_queue(void)
2285 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
2286 sizeof(struct scsi_data_buffer
),
2288 if (!scsi_sdb_cache
) {
2289 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
2296 void scsi_exit_queue(void)
2298 kmem_cache_destroy(scsi_sense_cache
);
2299 kmem_cache_destroy(scsi_sense_isadma_cache
);
2300 kmem_cache_destroy(scsi_sdb_cache
);
2304 * scsi_mode_select - issue a mode select
2305 * @sdev: SCSI device to be queried
2306 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2307 * @sp: Save page bit (0 == don't save, 1 == save)
2308 * @modepage: mode page being requested
2309 * @buffer: request buffer (may not be smaller than eight bytes)
2310 * @len: length of request buffer.
2311 * @timeout: command timeout
2312 * @retries: number of retries before failing
2313 * @data: returns a structure abstracting the mode header data
2314 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2315 * must be SCSI_SENSE_BUFFERSIZE big.
2317 * Returns zero if successful; negative error number or scsi
2322 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
2323 unsigned char *buffer
, int len
, int timeout
, int retries
,
2324 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2326 unsigned char cmd
[10];
2327 unsigned char *real_buffer
;
2330 memset(cmd
, 0, sizeof(cmd
));
2331 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
2333 if (sdev
->use_10_for_ms
) {
2336 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
2339 memcpy(real_buffer
+ 8, buffer
, len
);
2343 real_buffer
[2] = data
->medium_type
;
2344 real_buffer
[3] = data
->device_specific
;
2345 real_buffer
[4] = data
->longlba
? 0x01 : 0;
2347 real_buffer
[6] = data
->block_descriptor_length
>> 8;
2348 real_buffer
[7] = data
->block_descriptor_length
;
2350 cmd
[0] = MODE_SELECT_10
;
2354 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2358 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2361 memcpy(real_buffer
+ 4, buffer
, len
);
2364 real_buffer
[1] = data
->medium_type
;
2365 real_buffer
[2] = data
->device_specific
;
2366 real_buffer
[3] = data
->block_descriptor_length
;
2369 cmd
[0] = MODE_SELECT
;
2373 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2374 sshdr
, timeout
, retries
, NULL
);
2378 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2381 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2382 * @sdev: SCSI device to be queried
2383 * @dbd: set if mode sense will allow block descriptors to be returned
2384 * @modepage: mode page being requested
2385 * @buffer: request buffer (may not be smaller than eight bytes)
2386 * @len: length of request buffer.
2387 * @timeout: command timeout
2388 * @retries: number of retries before failing
2389 * @data: returns a structure abstracting the mode header data
2390 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2391 * must be SCSI_SENSE_BUFFERSIZE big.
2393 * Returns zero if unsuccessful, or the header offset (either 4
2394 * or 8 depending on whether a six or ten byte command was
2395 * issued) if successful.
2398 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2399 unsigned char *buffer
, int len
, int timeout
, int retries
,
2400 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2402 unsigned char cmd
[12];
2405 int result
, retry_count
= retries
;
2406 struct scsi_sense_hdr my_sshdr
;
2408 memset(data
, 0, sizeof(*data
));
2409 memset(&cmd
[0], 0, 12);
2410 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2413 /* caller might not be interested in sense, but we need it */
2418 use_10_for_ms
= sdev
->use_10_for_ms
;
2420 if (use_10_for_ms
) {
2424 cmd
[0] = MODE_SENSE_10
;
2431 cmd
[0] = MODE_SENSE
;
2436 memset(buffer
, 0, len
);
2438 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2439 sshdr
, timeout
, retries
, NULL
);
2441 /* This code looks awful: what it's doing is making sure an
2442 * ILLEGAL REQUEST sense return identifies the actual command
2443 * byte as the problem. MODE_SENSE commands can return
2444 * ILLEGAL REQUEST if the code page isn't supported */
2446 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2447 (driver_byte(result
) & DRIVER_SENSE
)) {
2448 if (scsi_sense_valid(sshdr
)) {
2449 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2450 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2452 * Invalid command operation code
2454 sdev
->use_10_for_ms
= 0;
2460 if(scsi_status_is_good(result
)) {
2461 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2462 (modepage
== 6 || modepage
== 8))) {
2463 /* Initio breakage? */
2466 data
->medium_type
= 0;
2467 data
->device_specific
= 0;
2469 data
->block_descriptor_length
= 0;
2470 } else if(use_10_for_ms
) {
2471 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2472 data
->medium_type
= buffer
[2];
2473 data
->device_specific
= buffer
[3];
2474 data
->longlba
= buffer
[4] & 0x01;
2475 data
->block_descriptor_length
= buffer
[6]*256
2478 data
->length
= buffer
[0] + 1;
2479 data
->medium_type
= buffer
[1];
2480 data
->device_specific
= buffer
[2];
2481 data
->block_descriptor_length
= buffer
[3];
2483 data
->header_length
= header_length
;
2484 } else if ((status_byte(result
) == CHECK_CONDITION
) &&
2485 scsi_sense_valid(sshdr
) &&
2486 sshdr
->sense_key
== UNIT_ATTENTION
&& retry_count
) {
2493 EXPORT_SYMBOL(scsi_mode_sense
);
2496 * scsi_test_unit_ready - test if unit is ready
2497 * @sdev: scsi device to change the state of.
2498 * @timeout: command timeout
2499 * @retries: number of retries before failing
2500 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2501 * returning sense. Make sure that this is cleared before passing
2504 * Returns zero if unsuccessful or an error if TUR failed. For
2505 * removable media, UNIT_ATTENTION sets ->changed flag.
2508 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2509 struct scsi_sense_hdr
*sshdr_external
)
2512 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2514 struct scsi_sense_hdr
*sshdr
;
2517 if (!sshdr_external
)
2518 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2520 sshdr
= sshdr_external
;
2522 /* try to eat the UNIT_ATTENTION if there are enough retries */
2524 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2525 timeout
, retries
, NULL
);
2526 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2527 sshdr
->sense_key
== UNIT_ATTENTION
)
2529 } while (scsi_sense_valid(sshdr
) &&
2530 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2532 if (!sshdr_external
)
2536 EXPORT_SYMBOL(scsi_test_unit_ready
);
2539 * scsi_device_set_state - Take the given device through the device state model.
2540 * @sdev: scsi device to change the state of.
2541 * @state: state to change to.
2543 * Returns zero if unsuccessful or an error if the requested
2544 * transition is illegal.
2547 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2549 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2551 if (state
== oldstate
)
2557 case SDEV_CREATED_BLOCK
:
2568 case SDEV_TRANSPORT_OFFLINE
:
2581 case SDEV_TRANSPORT_OFFLINE
:
2589 case SDEV_TRANSPORT_OFFLINE
:
2604 case SDEV_CREATED_BLOCK
:
2611 case SDEV_CREATED_BLOCK
:
2626 case SDEV_TRANSPORT_OFFLINE
:
2639 case SDEV_TRANSPORT_OFFLINE
:
2641 case SDEV_CREATED_BLOCK
:
2649 sdev
->sdev_state
= state
;
2653 SCSI_LOG_ERROR_RECOVERY(1,
2654 sdev_printk(KERN_ERR
, sdev
,
2655 "Illegal state transition %s->%s",
2656 scsi_device_state_name(oldstate
),
2657 scsi_device_state_name(state
))
2661 EXPORT_SYMBOL(scsi_device_set_state
);
2664 * sdev_evt_emit - emit a single SCSI device uevent
2665 * @sdev: associated SCSI device
2666 * @evt: event to emit
2668 * Send a single uevent (scsi_event) to the associated scsi_device.
2670 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2675 switch (evt
->evt_type
) {
2676 case SDEV_EVT_MEDIA_CHANGE
:
2677 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2679 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2680 scsi_rescan_device(&sdev
->sdev_gendev
);
2681 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2683 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2684 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2686 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2687 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2689 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2690 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2692 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2693 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2695 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2696 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2705 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2709 * sdev_evt_thread - send a uevent for each scsi event
2710 * @work: work struct for scsi_device
2712 * Dispatch queued events to their associated scsi_device kobjects
2715 void scsi_evt_thread(struct work_struct
*work
)
2717 struct scsi_device
*sdev
;
2718 enum scsi_device_event evt_type
;
2719 LIST_HEAD(event_list
);
2721 sdev
= container_of(work
, struct scsi_device
, event_work
);
2723 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2724 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2725 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2728 struct scsi_event
*evt
;
2729 struct list_head
*this, *tmp
;
2730 unsigned long flags
;
2732 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2733 list_splice_init(&sdev
->event_list
, &event_list
);
2734 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2736 if (list_empty(&event_list
))
2739 list_for_each_safe(this, tmp
, &event_list
) {
2740 evt
= list_entry(this, struct scsi_event
, node
);
2741 list_del(&evt
->node
);
2742 scsi_evt_emit(sdev
, evt
);
2749 * sdev_evt_send - send asserted event to uevent thread
2750 * @sdev: scsi_device event occurred on
2751 * @evt: event to send
2753 * Assert scsi device event asynchronously.
2755 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2757 unsigned long flags
;
2760 /* FIXME: currently this check eliminates all media change events
2761 * for polled devices. Need to update to discriminate between AN
2762 * and polled events */
2763 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2769 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2770 list_add_tail(&evt
->node
, &sdev
->event_list
);
2771 schedule_work(&sdev
->event_work
);
2772 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2774 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2777 * sdev_evt_alloc - allocate a new scsi event
2778 * @evt_type: type of event to allocate
2779 * @gfpflags: GFP flags for allocation
2781 * Allocates and returns a new scsi_event.
2783 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2786 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2790 evt
->evt_type
= evt_type
;
2791 INIT_LIST_HEAD(&evt
->node
);
2793 /* evt_type-specific initialization, if any */
2795 case SDEV_EVT_MEDIA_CHANGE
:
2796 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2797 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2798 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2799 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2800 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2801 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2809 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2812 * sdev_evt_send_simple - send asserted event to uevent thread
2813 * @sdev: scsi_device event occurred on
2814 * @evt_type: type of event to send
2815 * @gfpflags: GFP flags for allocation
2817 * Assert scsi device event asynchronously, given an event type.
2819 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2820 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2822 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2824 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2829 sdev_evt_send(sdev
, evt
);
2831 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2834 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2835 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2837 static int scsi_request_fn_active(struct scsi_device
*sdev
)
2839 struct request_queue
*q
= sdev
->request_queue
;
2840 int request_fn_active
;
2842 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2844 spin_lock_irq(q
->queue_lock
);
2845 request_fn_active
= q
->request_fn_active
;
2846 spin_unlock_irq(q
->queue_lock
);
2848 return request_fn_active
;
2852 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2853 * @sdev: SCSI device pointer.
2855 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2856 * invoked from scsi_request_fn() have finished.
2858 static void scsi_wait_for_queuecommand(struct scsi_device
*sdev
)
2860 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2862 while (scsi_request_fn_active(sdev
))
2867 * scsi_device_quiesce - Block user issued commands.
2868 * @sdev: scsi device to quiesce.
2870 * This works by trying to transition to the SDEV_QUIESCE state
2871 * (which must be a legal transition). When the device is in this
2872 * state, only special requests will be accepted, all others will
2873 * be deferred. Since special requests may also be requeued requests,
2874 * a successful return doesn't guarantee the device will be
2875 * totally quiescent.
2877 * Must be called with user context, may sleep.
2879 * Returns zero if unsuccessful or an error if not.
2882 scsi_device_quiesce(struct scsi_device
*sdev
)
2884 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2888 scsi_run_queue(sdev
->request_queue
);
2889 while (atomic_read(&sdev
->device_busy
)) {
2890 msleep_interruptible(200);
2891 scsi_run_queue(sdev
->request_queue
);
2895 EXPORT_SYMBOL(scsi_device_quiesce
);
2898 * scsi_device_resume - Restart user issued commands to a quiesced device.
2899 * @sdev: scsi device to resume.
2901 * Moves the device from quiesced back to running and restarts the
2904 * Must be called with user context, may sleep.
2906 void scsi_device_resume(struct scsi_device
*sdev
)
2908 /* check if the device state was mutated prior to resume, and if
2909 * so assume the state is being managed elsewhere (for example
2910 * device deleted during suspend)
2912 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2913 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2915 scsi_run_queue(sdev
->request_queue
);
2917 EXPORT_SYMBOL(scsi_device_resume
);
2920 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2922 scsi_device_quiesce(sdev
);
2926 scsi_target_quiesce(struct scsi_target
*starget
)
2928 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2930 EXPORT_SYMBOL(scsi_target_quiesce
);
2933 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2935 scsi_device_resume(sdev
);
2939 scsi_target_resume(struct scsi_target
*starget
)
2941 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2943 EXPORT_SYMBOL(scsi_target_resume
);
2946 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2947 * @sdev: device to block
2949 * Block request made by scsi lld's to temporarily stop all
2950 * scsi commands on the specified device. May sleep.
2952 * Returns zero if successful or error if not
2955 * This routine transitions the device to the SDEV_BLOCK state
2956 * (which must be a legal transition). When the device is in this
2957 * state, all commands are deferred until the scsi lld reenables
2958 * the device with scsi_device_unblock or device_block_tmo fires.
2960 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2961 * scsi_internal_device_block() has blocked a SCSI device and also
2962 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2965 scsi_internal_device_block(struct scsi_device
*sdev
)
2967 struct request_queue
*q
= sdev
->request_queue
;
2968 unsigned long flags
;
2971 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2973 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2980 * The device has transitioned to SDEV_BLOCK. Stop the
2981 * block layer from calling the midlayer with this device's
2985 blk_mq_quiesce_queue(q
);
2987 spin_lock_irqsave(q
->queue_lock
, flags
);
2989 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2990 scsi_wait_for_queuecommand(sdev
);
2995 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2998 * scsi_internal_device_unblock - resume a device after a block request
2999 * @sdev: device to resume
3000 * @new_state: state to set devices to after unblocking
3002 * Called by scsi lld's or the midlayer to restart the device queue
3003 * for the previously suspended scsi device. Called from interrupt or
3004 * normal process context.
3006 * Returns zero if successful or error if not.
3009 * This routine transitions the device to the SDEV_RUNNING state
3010 * or to one of the offline states (which must be a legal transition)
3011 * allowing the midlayer to goose the queue for this device.
3014 scsi_internal_device_unblock(struct scsi_device
*sdev
,
3015 enum scsi_device_state new_state
)
3017 struct request_queue
*q
= sdev
->request_queue
;
3018 unsigned long flags
;
3021 * Try to transition the scsi device to SDEV_RUNNING or one of the
3022 * offlined states and goose the device queue if successful.
3024 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
3025 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
3026 sdev
->sdev_state
= new_state
;
3027 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
3028 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3029 new_state
== SDEV_OFFLINE
)
3030 sdev
->sdev_state
= new_state
;
3032 sdev
->sdev_state
= SDEV_CREATED
;
3033 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
3034 sdev
->sdev_state
!= SDEV_OFFLINE
)
3038 blk_mq_start_stopped_hw_queues(q
, false);
3040 spin_lock_irqsave(q
->queue_lock
, flags
);
3042 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3047 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
3050 device_block(struct scsi_device
*sdev
, void *data
)
3052 scsi_internal_device_block(sdev
);
3056 target_block(struct device
*dev
, void *data
)
3058 if (scsi_is_target_device(dev
))
3059 starget_for_each_device(to_scsi_target(dev
), NULL
,
3065 scsi_target_block(struct device
*dev
)
3067 if (scsi_is_target_device(dev
))
3068 starget_for_each_device(to_scsi_target(dev
), NULL
,
3071 device_for_each_child(dev
, NULL
, target_block
);
3073 EXPORT_SYMBOL_GPL(scsi_target_block
);
3076 device_unblock(struct scsi_device
*sdev
, void *data
)
3078 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3082 target_unblock(struct device
*dev
, void *data
)
3084 if (scsi_is_target_device(dev
))
3085 starget_for_each_device(to_scsi_target(dev
), data
,
3091 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3093 if (scsi_is_target_device(dev
))
3094 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3097 device_for_each_child(dev
, &new_state
, target_unblock
);
3099 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3102 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3103 * @sgl: scatter-gather list
3104 * @sg_count: number of segments in sg
3105 * @offset: offset in bytes into sg, on return offset into the mapped area
3106 * @len: bytes to map, on return number of bytes mapped
3108 * Returns virtual address of the start of the mapped page
3110 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3111 size_t *offset
, size_t *len
)
3114 size_t sg_len
= 0, len_complete
= 0;
3115 struct scatterlist
*sg
;
3118 WARN_ON(!irqs_disabled());
3120 for_each_sg(sgl
, sg
, sg_count
, i
) {
3121 len_complete
= sg_len
; /* Complete sg-entries */
3122 sg_len
+= sg
->length
;
3123 if (sg_len
> *offset
)
3127 if (unlikely(i
== sg_count
)) {
3128 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3130 __func__
, sg_len
, *offset
, sg_count
);
3135 /* Offset starting from the beginning of first page in this sg-entry */
3136 *offset
= *offset
- len_complete
+ sg
->offset
;
3138 /* Assumption: contiguous pages can be accessed as "page + i" */
3139 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3140 *offset
&= ~PAGE_MASK
;
3142 /* Bytes in this sg-entry from *offset to the end of the page */
3143 sg_len
= PAGE_SIZE
- *offset
;
3147 return kmap_atomic(page
);
3149 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3152 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3153 * @virt: virtual address to be unmapped
3155 void scsi_kunmap_atomic_sg(void *virt
)
3157 kunmap_atomic(virt
);
3159 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3161 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3163 atomic_inc(&sdev
->disk_events_disable_depth
);
3165 EXPORT_SYMBOL(sdev_disable_disk_events
);
3167 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3169 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3171 atomic_dec(&sdev
->disk_events_disable_depth
);
3173 EXPORT_SYMBOL(sdev_enable_disk_events
);
3176 * scsi_vpd_lun_id - return a unique device identification
3177 * @sdev: SCSI device
3178 * @id: buffer for the identification
3179 * @id_len: length of the buffer
3181 * Copies a unique device identification into @id based
3182 * on the information in the VPD page 0x83 of the device.
3183 * The string will be formatted as a SCSI name string.
3185 * Returns the length of the identification or error on failure.
3186 * If the identifier is longer than the supplied buffer the actual
3187 * identifier length is returned and the buffer is not zero-padded.
3189 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3191 u8 cur_id_type
= 0xff;
3193 unsigned char *d
, *cur_id_str
;
3194 unsigned char __rcu
*vpd_pg83
;
3195 int id_size
= -EINVAL
;
3198 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3205 * Look for the correct descriptor.
3206 * Order of preference for lun descriptor:
3207 * - SCSI name string
3208 * - NAA IEEE Registered Extended
3209 * - EUI-64 based 16-byte
3210 * - EUI-64 based 12-byte
3211 * - NAA IEEE Registered
3212 * - NAA IEEE Extended
3214 * as longer descriptors reduce the likelyhood
3215 * of identification clashes.
3218 /* The id string must be at least 20 bytes + terminating NULL byte */
3224 memset(id
, 0, id_len
);
3226 while (d
< vpd_pg83
+ sdev
->vpd_pg83_len
) {
3227 /* Skip designators not referring to the LUN */
3228 if ((d
[1] & 0x30) != 0x00)
3231 switch (d
[1] & 0xf) {
3234 if (cur_id_size
> d
[3])
3236 /* Prefer anything */
3237 if (cur_id_type
> 0x01 && cur_id_type
!= 0xff)
3240 if (cur_id_size
+ 4 > id_len
)
3241 cur_id_size
= id_len
- 4;
3243 cur_id_type
= d
[1] & 0xf;
3244 id_size
= snprintf(id
, id_len
, "t10.%*pE",
3245 cur_id_size
, cur_id_str
);
3249 if (cur_id_size
> d
[3])
3251 /* Prefer NAA IEEE Registered Extended */
3252 if (cur_id_type
== 0x3 &&
3253 cur_id_size
== d
[3])
3257 cur_id_type
= d
[1] & 0xf;
3258 switch (cur_id_size
) {
3260 id_size
= snprintf(id
, id_len
,
3265 id_size
= snprintf(id
, id_len
,
3270 id_size
= snprintf(id
, id_len
,
3281 if (cur_id_size
> d
[3])
3285 cur_id_type
= d
[1] & 0xf;
3286 switch (cur_id_size
) {
3288 id_size
= snprintf(id
, id_len
,
3293 id_size
= snprintf(id
, id_len
,
3303 /* SCSI name string */
3304 if (cur_id_size
+ 4 > d
[3])
3306 /* Prefer others for truncated descriptor */
3307 if (cur_id_size
&& d
[3] > id_len
)
3309 cur_id_size
= id_size
= d
[3];
3311 cur_id_type
= d
[1] & 0xf;
3312 if (cur_id_size
>= id_len
)
3313 cur_id_size
= id_len
- 1;
3314 memcpy(id
, cur_id_str
, cur_id_size
);
3315 /* Decrease priority for truncated descriptor */
3316 if (cur_id_size
!= id_size
)
3329 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3332 * scsi_vpd_tpg_id - return a target port group identifier
3333 * @sdev: SCSI device
3335 * Returns the Target Port Group identifier from the information
3336 * froom VPD page 0x83 of the device.
3338 * Returns the identifier or error on failure.
3340 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3343 unsigned char __rcu
*vpd_pg83
;
3344 int group_id
= -EAGAIN
, rel_port
= -1;
3347 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3353 d
= sdev
->vpd_pg83
+ 4;
3354 while (d
< sdev
->vpd_pg83
+ sdev
->vpd_pg83_len
) {
3355 switch (d
[1] & 0xf) {
3357 /* Relative target port */
3358 rel_port
= get_unaligned_be16(&d
[6]);
3361 /* Target port group */
3362 group_id
= get_unaligned_be16(&d
[6]);
3371 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3376 EXPORT_SYMBOL(scsi_vpd_tpg_id
);