2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
11 #include <linux/bio.h>
12 #include <linux/bitops.h>
13 #include <linux/blkdev.h>
14 #include <linux/completion.h>
15 #include <linux/kernel.h>
16 #include <linux/export.h>
17 #include <linux/init.h>
18 #include <linux/pci.h>
19 #include <linux/delay.h>
20 #include <linux/hardirq.h>
21 #include <linux/scatterlist.h>
22 #include <linux/blk-mq.h>
23 #include <linux/ratelimit.h>
24 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_driver.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_host.h>
33 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
34 #include <scsi/scsi_dh.h>
36 #include <trace/events/scsi.h>
38 #include "scsi_debugfs.h"
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
42 static struct kmem_cache
*scsi_sdb_cache
;
43 static struct kmem_cache
*scsi_sense_cache
;
44 static struct kmem_cache
*scsi_sense_isadma_cache
;
45 static DEFINE_MUTEX(scsi_sense_cache_mutex
);
47 static inline struct kmem_cache
*
48 scsi_select_sense_cache(struct Scsi_Host
*shost
)
50 return shost
->unchecked_isa_dma
?
51 scsi_sense_isadma_cache
: scsi_sense_cache
;
54 static void scsi_free_sense_buffer(struct Scsi_Host
*shost
,
55 unsigned char *sense_buffer
)
57 kmem_cache_free(scsi_select_sense_cache(shost
), sense_buffer
);
60 static unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host
*shost
,
61 gfp_t gfp_mask
, int numa_node
)
63 return kmem_cache_alloc_node(scsi_select_sense_cache(shost
), gfp_mask
,
67 int scsi_init_sense_cache(struct Scsi_Host
*shost
)
69 struct kmem_cache
*cache
;
72 cache
= scsi_select_sense_cache(shost
);
76 mutex_lock(&scsi_sense_cache_mutex
);
77 if (shost
->unchecked_isa_dma
) {
78 scsi_sense_isadma_cache
=
79 kmem_cache_create("scsi_sense_cache(DMA)",
80 SCSI_SENSE_BUFFERSIZE
, 0,
81 SLAB_HWCACHE_ALIGN
| SLAB_CACHE_DMA
, NULL
);
82 if (!scsi_sense_isadma_cache
)
86 kmem_cache_create("scsi_sense_cache",
87 SCSI_SENSE_BUFFERSIZE
, 0, SLAB_HWCACHE_ALIGN
, NULL
);
88 if (!scsi_sense_cache
)
92 mutex_unlock(&scsi_sense_cache_mutex
);
97 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
98 * not change behaviour from the previous unplug mechanism, experimentation
99 * may prove this needs changing.
101 #define SCSI_QUEUE_DELAY 3
104 scsi_set_blocked(struct scsi_cmnd
*cmd
, int reason
)
106 struct Scsi_Host
*host
= cmd
->device
->host
;
107 struct scsi_device
*device
= cmd
->device
;
108 struct scsi_target
*starget
= scsi_target(device
);
111 * Set the appropriate busy bit for the device/host.
113 * If the host/device isn't busy, assume that something actually
114 * completed, and that we should be able to queue a command now.
116 * Note that the prior mid-layer assumption that any host could
117 * always queue at least one command is now broken. The mid-layer
118 * will implement a user specifiable stall (see
119 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
120 * if a command is requeued with no other commands outstanding
121 * either for the device or for the host.
124 case SCSI_MLQUEUE_HOST_BUSY
:
125 atomic_set(&host
->host_blocked
, host
->max_host_blocked
);
127 case SCSI_MLQUEUE_DEVICE_BUSY
:
128 case SCSI_MLQUEUE_EH_RETRY
:
129 atomic_set(&device
->device_blocked
,
130 device
->max_device_blocked
);
132 case SCSI_MLQUEUE_TARGET_BUSY
:
133 atomic_set(&starget
->target_blocked
,
134 starget
->max_target_blocked
);
139 static void scsi_mq_requeue_cmd(struct scsi_cmnd
*cmd
)
141 struct scsi_device
*sdev
= cmd
->device
;
143 blk_mq_requeue_request(cmd
->request
, true);
144 put_device(&sdev
->sdev_gendev
);
148 * __scsi_queue_insert - private queue insertion
149 * @cmd: The SCSI command being requeued
150 * @reason: The reason for the requeue
151 * @unbusy: Whether the queue should be unbusied
153 * This is a private queue insertion. The public interface
154 * scsi_queue_insert() always assumes the queue should be unbusied
155 * because it's always called before the completion. This function is
156 * for a requeue after completion, which should only occur in this
159 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
161 struct scsi_device
*device
= cmd
->device
;
162 struct request_queue
*q
= device
->request_queue
;
165 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO
, cmd
,
166 "Inserting command %p into mlqueue\n", cmd
));
168 scsi_set_blocked(cmd
, reason
);
171 * Decrement the counters, since these commands are no longer
172 * active on the host/device.
175 scsi_device_unbusy(device
);
178 * Requeue this command. It will go before all other commands
179 * that are already in the queue. Schedule requeue work under
180 * lock such that the kblockd_schedule_work() call happens
181 * before blk_cleanup_queue() finishes.
185 scsi_mq_requeue_cmd(cmd
);
188 spin_lock_irqsave(q
->queue_lock
, flags
);
189 blk_requeue_request(q
, cmd
->request
);
190 kblockd_schedule_work(&device
->requeue_work
);
191 spin_unlock_irqrestore(q
->queue_lock
, flags
);
195 * Function: scsi_queue_insert()
197 * Purpose: Insert a command in the midlevel queue.
199 * Arguments: cmd - command that we are adding to queue.
200 * reason - why we are inserting command to queue.
202 * Lock status: Assumed that lock is not held upon entry.
206 * Notes: We do this for one of two cases. Either the host is busy
207 * and it cannot accept any more commands for the time being,
208 * or the device returned QUEUE_FULL and can accept no more
210 * Notes: This could be called either from an interrupt context or a
211 * normal process context.
213 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
215 __scsi_queue_insert(cmd
, reason
, 1);
220 * scsi_execute - insert request and wait for the result
223 * @data_direction: data direction
224 * @buffer: data buffer
225 * @bufflen: len of buffer
226 * @sense: optional sense buffer
227 * @sshdr: optional decoded sense header
228 * @timeout: request timeout in seconds
229 * @retries: number of times to retry request
230 * @flags: flags for ->cmd_flags
231 * @rq_flags: flags for ->rq_flags
232 * @resid: optional residual length
234 * Returns the scsi_cmnd result field if a command was executed, or a negative
235 * Linux error code if we didn't get that far.
237 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
238 int data_direction
, void *buffer
, unsigned bufflen
,
239 unsigned char *sense
, struct scsi_sense_hdr
*sshdr
,
240 int timeout
, int retries
, u64 flags
, req_flags_t rq_flags
,
244 struct scsi_request
*rq
;
245 int ret
= DRIVER_ERROR
<< 24;
247 req
= blk_get_request(sdev
->request_queue
,
248 data_direction
== DMA_TO_DEVICE
?
249 REQ_OP_SCSI_OUT
: REQ_OP_SCSI_IN
, __GFP_RECLAIM
);
255 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
256 buffer
, bufflen
, __GFP_RECLAIM
))
259 rq
->cmd_len
= COMMAND_SIZE(cmd
[0]);
260 memcpy(rq
->cmd
, cmd
, rq
->cmd_len
);
261 rq
->retries
= retries
;
262 req
->timeout
= timeout
;
263 req
->cmd_flags
|= flags
;
264 req
->rq_flags
|= rq_flags
| RQF_QUIET
| RQF_PREEMPT
;
267 * head injection *required* here otherwise quiesce won't work
269 blk_execute_rq(req
->q
, NULL
, req
, 1);
272 * Some devices (USB mass-storage in particular) may transfer
273 * garbage data together with a residue indicating that the data
274 * is invalid. Prevent the garbage from being misinterpreted
275 * and prevent security leaks by zeroing out the excess data.
277 if (unlikely(rq
->resid_len
> 0 && rq
->resid_len
<= bufflen
))
278 memset(buffer
+ (bufflen
- rq
->resid_len
), 0, rq
->resid_len
);
281 *resid
= rq
->resid_len
;
282 if (sense
&& rq
->sense_len
)
283 memcpy(sense
, rq
->sense
, SCSI_SENSE_BUFFERSIZE
);
285 scsi_normalize_sense(rq
->sense
, rq
->sense_len
, sshdr
);
288 blk_put_request(req
);
292 EXPORT_SYMBOL(scsi_execute
);
295 * Function: scsi_init_cmd_errh()
297 * Purpose: Initialize cmd fields related to error handling.
299 * Arguments: cmd - command that is ready to be queued.
301 * Notes: This function has the job of initializing a number of
302 * fields related to error handling. Typically this will
303 * be called once for each command, as required.
305 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
307 cmd
->serial_number
= 0;
308 scsi_set_resid(cmd
, 0);
309 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
310 if (cmd
->cmd_len
== 0)
311 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
314 void scsi_device_unbusy(struct scsi_device
*sdev
)
316 struct Scsi_Host
*shost
= sdev
->host
;
317 struct scsi_target
*starget
= scsi_target(sdev
);
320 atomic_dec(&shost
->host_busy
);
321 if (starget
->can_queue
> 0)
322 atomic_dec(&starget
->target_busy
);
324 if (unlikely(scsi_host_in_recovery(shost
) &&
325 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
326 spin_lock_irqsave(shost
->host_lock
, flags
);
327 scsi_eh_wakeup(shost
);
328 spin_unlock_irqrestore(shost
->host_lock
, flags
);
331 atomic_dec(&sdev
->device_busy
);
334 static void scsi_kick_queue(struct request_queue
*q
)
337 blk_mq_start_hw_queues(q
);
343 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
344 * and call blk_run_queue for all the scsi_devices on the target -
345 * including current_sdev first.
347 * Called with *no* scsi locks held.
349 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
351 struct Scsi_Host
*shost
= current_sdev
->host
;
352 struct scsi_device
*sdev
, *tmp
;
353 struct scsi_target
*starget
= scsi_target(current_sdev
);
356 spin_lock_irqsave(shost
->host_lock
, flags
);
357 starget
->starget_sdev_user
= NULL
;
358 spin_unlock_irqrestore(shost
->host_lock
, flags
);
361 * Call blk_run_queue for all LUNs on the target, starting with
362 * current_sdev. We race with others (to set starget_sdev_user),
363 * but in most cases, we will be first. Ideally, each LU on the
364 * target would get some limited time or requests on the target.
366 scsi_kick_queue(current_sdev
->request_queue
);
368 spin_lock_irqsave(shost
->host_lock
, flags
);
369 if (starget
->starget_sdev_user
)
371 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
372 same_target_siblings
) {
373 if (sdev
== current_sdev
)
375 if (scsi_device_get(sdev
))
378 spin_unlock_irqrestore(shost
->host_lock
, flags
);
379 scsi_kick_queue(sdev
->request_queue
);
380 spin_lock_irqsave(shost
->host_lock
, flags
);
382 scsi_device_put(sdev
);
385 spin_unlock_irqrestore(shost
->host_lock
, flags
);
388 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
390 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
392 if (atomic_read(&sdev
->device_blocked
) > 0)
397 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
399 if (starget
->can_queue
> 0) {
400 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
402 if (atomic_read(&starget
->target_blocked
) > 0)
408 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
410 if (shost
->can_queue
> 0 &&
411 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
413 if (atomic_read(&shost
->host_blocked
) > 0)
415 if (shost
->host_self_blocked
)
420 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
422 LIST_HEAD(starved_list
);
423 struct scsi_device
*sdev
;
426 spin_lock_irqsave(shost
->host_lock
, flags
);
427 list_splice_init(&shost
->starved_list
, &starved_list
);
429 while (!list_empty(&starved_list
)) {
430 struct request_queue
*slq
;
433 * As long as shost is accepting commands and we have
434 * starved queues, call blk_run_queue. scsi_request_fn
435 * drops the queue_lock and can add us back to the
438 * host_lock protects the starved_list and starved_entry.
439 * scsi_request_fn must get the host_lock before checking
440 * or modifying starved_list or starved_entry.
442 if (scsi_host_is_busy(shost
))
445 sdev
= list_entry(starved_list
.next
,
446 struct scsi_device
, starved_entry
);
447 list_del_init(&sdev
->starved_entry
);
448 if (scsi_target_is_busy(scsi_target(sdev
))) {
449 list_move_tail(&sdev
->starved_entry
,
450 &shost
->starved_list
);
455 * Once we drop the host lock, a racing scsi_remove_device()
456 * call may remove the sdev from the starved list and destroy
457 * it and the queue. Mitigate by taking a reference to the
458 * queue and never touching the sdev again after we drop the
459 * host lock. Note: if __scsi_remove_device() invokes
460 * blk_cleanup_queue() before the queue is run from this
461 * function then blk_run_queue() will return immediately since
462 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
464 slq
= sdev
->request_queue
;
465 if (!blk_get_queue(slq
))
467 spin_unlock_irqrestore(shost
->host_lock
, flags
);
469 scsi_kick_queue(slq
);
472 spin_lock_irqsave(shost
->host_lock
, flags
);
474 /* put any unprocessed entries back */
475 list_splice(&starved_list
, &shost
->starved_list
);
476 spin_unlock_irqrestore(shost
->host_lock
, flags
);
480 * Function: scsi_run_queue()
482 * Purpose: Select a proper request queue to serve next
484 * Arguments: q - last request's queue
488 * Notes: The previous command was completely finished, start
489 * a new one if possible.
491 static void scsi_run_queue(struct request_queue
*q
)
493 struct scsi_device
*sdev
= q
->queuedata
;
495 if (scsi_target(sdev
)->single_lun
)
496 scsi_single_lun_run(sdev
);
497 if (!list_empty(&sdev
->host
->starved_list
))
498 scsi_starved_list_run(sdev
->host
);
501 blk_mq_run_hw_queues(q
, false);
506 void scsi_requeue_run_queue(struct work_struct
*work
)
508 struct scsi_device
*sdev
;
509 struct request_queue
*q
;
511 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
512 q
= sdev
->request_queue
;
517 * Function: scsi_requeue_command()
519 * Purpose: Handle post-processing of completed commands.
521 * Arguments: q - queue to operate on
522 * cmd - command that may need to be requeued.
526 * Notes: After command completion, there may be blocks left
527 * over which weren't finished by the previous command
528 * this can be for a number of reasons - the main one is
529 * I/O errors in the middle of the request, in which case
530 * we need to request the blocks that come after the bad
532 * Notes: Upon return, cmd is a stale pointer.
534 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
536 struct scsi_device
*sdev
= cmd
->device
;
537 struct request
*req
= cmd
->request
;
540 spin_lock_irqsave(q
->queue_lock
, flags
);
541 blk_unprep_request(req
);
543 scsi_put_command(cmd
);
544 blk_requeue_request(q
, req
);
545 spin_unlock_irqrestore(q
->queue_lock
, flags
);
549 put_device(&sdev
->sdev_gendev
);
552 void scsi_run_host_queues(struct Scsi_Host
*shost
)
554 struct scsi_device
*sdev
;
556 shost_for_each_device(sdev
, shost
)
557 scsi_run_queue(sdev
->request_queue
);
560 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
562 if (!blk_rq_is_passthrough(cmd
->request
)) {
563 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
565 if (drv
->uninit_command
)
566 drv
->uninit_command(cmd
);
570 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
572 struct scsi_data_buffer
*sdb
;
574 if (cmd
->sdb
.table
.nents
)
575 sg_free_table_chained(&cmd
->sdb
.table
, true);
576 if (cmd
->request
->next_rq
) {
577 sdb
= cmd
->request
->next_rq
->special
;
579 sg_free_table_chained(&sdb
->table
, true);
581 if (scsi_prot_sg_count(cmd
))
582 sg_free_table_chained(&cmd
->prot_sdb
->table
, true);
585 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
587 struct scsi_device
*sdev
= cmd
->device
;
588 struct Scsi_Host
*shost
= sdev
->host
;
591 scsi_mq_free_sgtables(cmd
);
592 scsi_uninit_cmd(cmd
);
594 if (shost
->use_cmd_list
) {
595 BUG_ON(list_empty(&cmd
->list
));
596 spin_lock_irqsave(&sdev
->list_lock
, flags
);
597 list_del_init(&cmd
->list
);
598 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
603 * Function: scsi_release_buffers()
605 * Purpose: Free resources allocate for a scsi_command.
607 * Arguments: cmd - command that we are bailing.
609 * Lock status: Assumed that no lock is held upon entry.
613 * Notes: In the event that an upper level driver rejects a
614 * command, we must release resources allocated during
615 * the __init_io() function. Primarily this would involve
616 * the scatter-gather table.
618 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
620 if (cmd
->sdb
.table
.nents
)
621 sg_free_table_chained(&cmd
->sdb
.table
, false);
623 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
625 if (scsi_prot_sg_count(cmd
))
626 sg_free_table_chained(&cmd
->prot_sdb
->table
, false);
629 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
631 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
633 sg_free_table_chained(&bidi_sdb
->table
, false);
634 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
635 cmd
->request
->next_rq
->special
= NULL
;
638 static bool scsi_end_request(struct request
*req
, int error
,
639 unsigned int bytes
, unsigned int bidi_bytes
)
641 struct scsi_cmnd
*cmd
= req
->special
;
642 struct scsi_device
*sdev
= cmd
->device
;
643 struct request_queue
*q
= sdev
->request_queue
;
645 if (blk_update_request(req
, error
, bytes
))
648 /* Bidi request must be completed as a whole */
649 if (unlikely(bidi_bytes
) &&
650 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
653 if (blk_queue_add_random(q
))
654 add_disk_randomness(req
->rq_disk
);
658 * In the MQ case the command gets freed by __blk_mq_end_request,
659 * so we have to do all cleanup that depends on it earlier.
661 * We also can't kick the queues from irq context, so we
662 * will have to defer it to a workqueue.
664 scsi_mq_uninit_cmd(cmd
);
666 __blk_mq_end_request(req
, error
);
668 if (scsi_target(sdev
)->single_lun
||
669 !list_empty(&sdev
->host
->starved_list
))
670 kblockd_schedule_work(&sdev
->requeue_work
);
672 blk_mq_run_hw_queues(q
, true);
677 scsi_release_bidi_buffers(cmd
);
678 scsi_release_buffers(cmd
);
679 scsi_put_command(cmd
);
681 spin_lock_irqsave(q
->queue_lock
, flags
);
682 blk_finish_request(req
, error
);
683 spin_unlock_irqrestore(q
->queue_lock
, flags
);
688 put_device(&sdev
->sdev_gendev
);
693 * __scsi_error_from_host_byte - translate SCSI error code into errno
694 * @cmd: SCSI command (unused)
695 * @result: scsi error code
697 * Translate SCSI error code into standard UNIX errno.
699 * -ENOLINK temporary transport failure
700 * -EREMOTEIO permanent target failure, do not retry
701 * -EBADE permanent nexus failure, retry on other path
702 * -ENOSPC No write space available
703 * -ENODATA Medium error
704 * -EIO unspecified I/O error
706 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
710 switch(host_byte(result
)) {
711 case DID_TRANSPORT_FAILFAST
:
714 case DID_TARGET_FAILURE
:
715 set_host_byte(cmd
, DID_OK
);
718 case DID_NEXUS_FAILURE
:
719 set_host_byte(cmd
, DID_OK
);
722 case DID_ALLOC_FAILURE
:
723 set_host_byte(cmd
, DID_OK
);
726 case DID_MEDIUM_ERROR
:
727 set_host_byte(cmd
, DID_OK
);
739 * Function: scsi_io_completion()
741 * Purpose: Completion processing for block device I/O requests.
743 * Arguments: cmd - command that is finished.
745 * Lock status: Assumed that no lock is held upon entry.
749 * Notes: We will finish off the specified number of sectors. If we
750 * are done, the command block will be released and the queue
751 * function will be goosed. If we are not done then we have to
752 * figure out what to do next:
754 * a) We can call scsi_requeue_command(). The request
755 * will be unprepared and put back on the queue. Then
756 * a new command will be created for it. This should
757 * be used if we made forward progress, or if we want
758 * to switch from READ(10) to READ(6) for example.
760 * b) We can call __scsi_queue_insert(). The request will
761 * be put back on the queue and retried using the same
762 * command as before, possibly after a delay.
764 * c) We can call scsi_end_request() with -EIO to fail
765 * the remainder of the request.
767 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
769 int result
= cmd
->result
;
770 struct request_queue
*q
= cmd
->device
->request_queue
;
771 struct request
*req
= cmd
->request
;
773 struct scsi_sense_hdr sshdr
;
774 bool sense_valid
= false;
775 int sense_deferred
= 0, level
= 0;
776 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
777 ACTION_DELAYED_RETRY
} action
;
778 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
781 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
783 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
786 if (blk_rq_is_passthrough(req
)) {
790 * SG_IO wants current and deferred errors
792 scsi_req(req
)->sense_len
=
793 min(8 + cmd
->sense_buffer
[7],
794 SCSI_SENSE_BUFFERSIZE
);
797 error
= __scsi_error_from_host_byte(cmd
, result
);
800 * __scsi_error_from_host_byte may have reset the host_byte
802 scsi_req(req
)->result
= cmd
->result
;
803 scsi_req(req
)->resid_len
= scsi_get_resid(cmd
);
805 if (scsi_bidi_cmnd(cmd
)) {
807 * Bidi commands Must be complete as a whole,
808 * both sides at once.
810 scsi_req(req
->next_rq
)->resid_len
= scsi_in(cmd
)->resid
;
811 if (scsi_end_request(req
, 0, blk_rq_bytes(req
),
812 blk_rq_bytes(req
->next_rq
)))
816 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
818 * Flush commands do not transfers any data, and thus cannot use
819 * good_bytes != blk_rq_bytes(req) as the signal for an error.
820 * This sets the error explicitly for the problem case.
822 error
= __scsi_error_from_host_byte(cmd
, result
);
825 /* no bidi support for !blk_rq_is_passthrough yet */
826 BUG_ON(blk_bidi_rq(req
));
829 * Next deal with any sectors which we were able to correctly
832 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO
, cmd
,
833 "%u sectors total, %d bytes done.\n",
834 blk_rq_sectors(req
), good_bytes
));
837 * Recovered errors need reporting, but they're always treated as
838 * success, so fiddle the result code here. For passthrough requests
839 * we already took a copy of the original into sreq->result which
840 * is what gets returned to the user
842 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
843 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
844 * print since caller wants ATA registers. Only occurs on
845 * SCSI ATA PASS_THROUGH commands when CK_COND=1
847 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
849 else if (!(req
->rq_flags
& RQF_QUIET
))
850 scsi_print_sense(cmd
);
852 /* for passthrough error may be set */
857 * special case: failed zero length commands always need to
858 * drop down into the retry code. Otherwise, if we finished
859 * all bytes in the request we are done now.
861 if (!(blk_rq_bytes(req
) == 0 && error
) &&
862 !scsi_end_request(req
, error
, good_bytes
, 0))
866 * Kill remainder if no retrys.
868 if (error
&& scsi_noretry_cmd(cmd
)) {
869 if (scsi_end_request(req
, error
, blk_rq_bytes(req
), 0))
875 * If there had been no error, but we have leftover bytes in the
876 * requeues just queue the command up again.
881 error
= __scsi_error_from_host_byte(cmd
, result
);
883 if (host_byte(result
) == DID_RESET
) {
884 /* Third party bus reset or reset for error recovery
885 * reasons. Just retry the command and see what
888 action
= ACTION_RETRY
;
889 } else if (sense_valid
&& !sense_deferred
) {
890 switch (sshdr
.sense_key
) {
892 if (cmd
->device
->removable
) {
893 /* Detected disc change. Set a bit
894 * and quietly refuse further access.
896 cmd
->device
->changed
= 1;
897 action
= ACTION_FAIL
;
899 /* Must have been a power glitch, or a
900 * bus reset. Could not have been a
901 * media change, so we just retry the
902 * command and see what happens.
904 action
= ACTION_RETRY
;
907 case ILLEGAL_REQUEST
:
908 /* If we had an ILLEGAL REQUEST returned, then
909 * we may have performed an unsupported
910 * command. The only thing this should be
911 * would be a ten byte read where only a six
912 * byte read was supported. Also, on a system
913 * where READ CAPACITY failed, we may have
914 * read past the end of the disk.
916 if ((cmd
->device
->use_10_for_rw
&&
917 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
918 (cmd
->cmnd
[0] == READ_10
||
919 cmd
->cmnd
[0] == WRITE_10
)) {
920 /* This will issue a new 6-byte command. */
921 cmd
->device
->use_10_for_rw
= 0;
922 action
= ACTION_REPREP
;
923 } else if (sshdr
.asc
== 0x10) /* DIX */ {
924 action
= ACTION_FAIL
;
926 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
927 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
928 action
= ACTION_FAIL
;
931 action
= ACTION_FAIL
;
933 case ABORTED_COMMAND
:
934 action
= ACTION_FAIL
;
935 if (sshdr
.asc
== 0x10) /* DIF */
939 /* If the device is in the process of becoming
940 * ready, or has a temporary blockage, retry.
942 if (sshdr
.asc
== 0x04) {
943 switch (sshdr
.ascq
) {
944 case 0x01: /* becoming ready */
945 case 0x04: /* format in progress */
946 case 0x05: /* rebuild in progress */
947 case 0x06: /* recalculation in progress */
948 case 0x07: /* operation in progress */
949 case 0x08: /* Long write in progress */
950 case 0x09: /* self test in progress */
951 case 0x14: /* space allocation in progress */
952 action
= ACTION_DELAYED_RETRY
;
955 action
= ACTION_FAIL
;
959 action
= ACTION_FAIL
;
961 case VOLUME_OVERFLOW
:
962 /* See SSC3rXX or current. */
963 action
= ACTION_FAIL
;
966 action
= ACTION_FAIL
;
970 action
= ACTION_FAIL
;
972 if (action
!= ACTION_FAIL
&&
973 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
))
974 action
= ACTION_FAIL
;
978 /* Give up and fail the remainder of the request */
979 if (!(req
->rq_flags
& RQF_QUIET
)) {
980 static DEFINE_RATELIMIT_STATE(_rs
,
981 DEFAULT_RATELIMIT_INTERVAL
,
982 DEFAULT_RATELIMIT_BURST
);
984 if (unlikely(scsi_logging_level
))
985 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
986 SCSI_LOG_MLCOMPLETE_BITS
);
989 * if logging is enabled the failure will be printed
990 * in scsi_log_completion(), so avoid duplicate messages
992 if (!level
&& __ratelimit(&_rs
)) {
993 scsi_print_result(cmd
, NULL
, FAILED
);
994 if (driver_byte(result
) & DRIVER_SENSE
)
995 scsi_print_sense(cmd
);
996 scsi_print_command(cmd
);
999 if (!scsi_end_request(req
, error
, blk_rq_err_bytes(req
), 0))
1004 /* Unprep the request and put it back at the head of the queue.
1005 * A new command will be prepared and issued.
1008 cmd
->request
->rq_flags
&= ~RQF_DONTPREP
;
1009 scsi_mq_uninit_cmd(cmd
);
1010 scsi_mq_requeue_cmd(cmd
);
1012 scsi_release_buffers(cmd
);
1013 scsi_requeue_command(q
, cmd
);
1017 /* Retry the same command immediately */
1018 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1020 case ACTION_DELAYED_RETRY
:
1021 /* Retry the same command after a delay */
1022 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1027 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
)
1032 * If sg table allocation fails, requeue request later.
1034 if (unlikely(sg_alloc_table_chained(&sdb
->table
,
1035 blk_rq_nr_phys_segments(req
), sdb
->table
.sgl
)))
1036 return BLKPREP_DEFER
;
1039 * Next, walk the list, and fill in the addresses and sizes of
1042 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1043 BUG_ON(count
> sdb
->table
.nents
);
1044 sdb
->table
.nents
= count
;
1045 sdb
->length
= blk_rq_payload_bytes(req
);
1050 * Function: scsi_init_io()
1052 * Purpose: SCSI I/O initialize function.
1054 * Arguments: cmd - Command descriptor we wish to initialize
1056 * Returns: 0 on success
1057 * BLKPREP_DEFER if the failure is retryable
1058 * BLKPREP_KILL if the failure is fatal
1060 int scsi_init_io(struct scsi_cmnd
*cmd
)
1062 struct scsi_device
*sdev
= cmd
->device
;
1063 struct request
*rq
= cmd
->request
;
1064 bool is_mq
= (rq
->mq_ctx
!= NULL
);
1065 int error
= BLKPREP_KILL
;
1067 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq
)))
1070 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1074 if (blk_bidi_rq(rq
)) {
1075 if (!rq
->q
->mq_ops
) {
1076 struct scsi_data_buffer
*bidi_sdb
=
1077 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1079 error
= BLKPREP_DEFER
;
1083 rq
->next_rq
->special
= bidi_sdb
;
1086 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1091 if (blk_integrity_rq(rq
)) {
1092 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1095 if (prot_sdb
== NULL
) {
1097 * This can happen if someone (e.g. multipath)
1098 * queues a command to a device on an adapter
1099 * that does not support DIX.
1102 error
= BLKPREP_KILL
;
1106 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1108 if (sg_alloc_table_chained(&prot_sdb
->table
, ivecs
,
1109 prot_sdb
->table
.sgl
)) {
1110 error
= BLKPREP_DEFER
;
1114 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1115 prot_sdb
->table
.sgl
);
1116 BUG_ON(unlikely(count
> ivecs
));
1117 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1119 cmd
->prot_sdb
= prot_sdb
;
1120 cmd
->prot_sdb
->table
.nents
= count
;
1126 scsi_mq_free_sgtables(cmd
);
1128 scsi_release_buffers(cmd
);
1129 cmd
->request
->special
= NULL
;
1130 scsi_put_command(cmd
);
1131 put_device(&sdev
->sdev_gendev
);
1135 EXPORT_SYMBOL(scsi_init_io
);
1137 void scsi_init_command(struct scsi_device
*dev
, struct scsi_cmnd
*cmd
)
1139 void *buf
= cmd
->sense_buffer
;
1140 void *prot
= cmd
->prot_sdb
;
1141 unsigned long flags
;
1143 /* zero out the cmd, except for the embedded scsi_request */
1144 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1145 sizeof(*cmd
) - sizeof(cmd
->req
) + dev
->host
->hostt
->cmd_size
);
1148 cmd
->sense_buffer
= buf
;
1149 cmd
->prot_sdb
= prot
;
1150 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1151 cmd
->jiffies_at_alloc
= jiffies
;
1153 spin_lock_irqsave(&dev
->list_lock
, flags
);
1154 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
1155 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
1158 static int scsi_setup_scsi_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1160 struct scsi_cmnd
*cmd
= req
->special
;
1163 * Passthrough requests may transfer data, in which case they must
1164 * a bio attached to them. Or they might contain a SCSI command
1165 * that does not transfer data, in which case they may optionally
1166 * submit a request without an attached bio.
1169 int ret
= scsi_init_io(cmd
);
1173 BUG_ON(blk_rq_bytes(req
));
1175 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1178 cmd
->cmd_len
= scsi_req(req
)->cmd_len
;
1179 cmd
->cmnd
= scsi_req(req
)->cmd
;
1180 cmd
->transfersize
= blk_rq_bytes(req
);
1181 cmd
->allowed
= scsi_req(req
)->retries
;
1186 * Setup a normal block command. These are simple request from filesystems
1187 * that still need to be translated to SCSI CDBs from the ULD.
1189 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1191 struct scsi_cmnd
*cmd
= req
->special
;
1193 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1194 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1195 if (ret
!= BLKPREP_OK
)
1199 cmd
->cmnd
= scsi_req(req
)->cmd
= scsi_req(req
)->__cmd
;
1200 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1201 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1204 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1206 struct scsi_cmnd
*cmd
= req
->special
;
1208 if (!blk_rq_bytes(req
))
1209 cmd
->sc_data_direction
= DMA_NONE
;
1210 else if (rq_data_dir(req
) == WRITE
)
1211 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1213 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1215 if (blk_rq_is_scsi(req
))
1216 return scsi_setup_scsi_cmnd(sdev
, req
);
1218 return scsi_setup_fs_cmnd(sdev
, req
);
1222 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1224 int ret
= BLKPREP_OK
;
1227 * If the device is not in running state we will reject some
1230 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1231 switch (sdev
->sdev_state
) {
1233 case SDEV_TRANSPORT_OFFLINE
:
1235 * If the device is offline we refuse to process any
1236 * commands. The device must be brought online
1237 * before trying any recovery commands.
1239 sdev_printk(KERN_ERR
, sdev
,
1240 "rejecting I/O to offline device\n");
1245 * If the device is fully deleted, we refuse to
1246 * process any commands as well.
1248 sdev_printk(KERN_ERR
, sdev
,
1249 "rejecting I/O to dead device\n");
1253 case SDEV_CREATED_BLOCK
:
1254 ret
= BLKPREP_DEFER
;
1258 * If the devices is blocked we defer normal commands.
1260 if (!(req
->rq_flags
& RQF_PREEMPT
))
1261 ret
= BLKPREP_DEFER
;
1265 * For any other not fully online state we only allow
1266 * special commands. In particular any user initiated
1267 * command is not allowed.
1269 if (!(req
->rq_flags
& RQF_PREEMPT
))
1278 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1280 struct scsi_device
*sdev
= q
->queuedata
;
1284 case BLKPREP_INVALID
:
1285 scsi_req(req
)->result
= DID_NO_CONNECT
<< 16;
1286 /* release the command and kill it */
1288 struct scsi_cmnd
*cmd
= req
->special
;
1289 scsi_release_buffers(cmd
);
1290 scsi_put_command(cmd
);
1291 put_device(&sdev
->sdev_gendev
);
1292 req
->special
= NULL
;
1297 * If we defer, the blk_peek_request() returns NULL, but the
1298 * queue must be restarted, so we schedule a callback to happen
1301 if (atomic_read(&sdev
->device_busy
) == 0)
1302 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1305 req
->rq_flags
|= RQF_DONTPREP
;
1311 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1313 struct scsi_device
*sdev
= q
->queuedata
;
1314 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1317 ret
= scsi_prep_state_check(sdev
, req
);
1318 if (ret
!= BLKPREP_OK
)
1321 if (!req
->special
) {
1322 /* Bail if we can't get a reference to the device */
1323 if (unlikely(!get_device(&sdev
->sdev_gendev
))) {
1324 ret
= BLKPREP_DEFER
;
1328 scsi_init_command(sdev
, cmd
);
1332 cmd
->tag
= req
->tag
;
1334 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1336 ret
= scsi_setup_cmnd(sdev
, req
);
1338 return scsi_prep_return(q
, req
, ret
);
1341 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1343 scsi_uninit_cmd(req
->special
);
1347 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1350 * Called with the queue_lock held.
1352 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1353 struct scsi_device
*sdev
)
1357 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1358 if (atomic_read(&sdev
->device_blocked
)) {
1363 * unblock after device_blocked iterates to zero
1365 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1367 * For the MQ case we take care of this in the caller.
1370 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1373 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1374 "unblocking device at zero depth\n"));
1377 if (busy
>= sdev
->queue_depth
)
1382 atomic_dec(&sdev
->device_busy
);
1387 * scsi_target_queue_ready: checks if there we can send commands to target
1388 * @sdev: scsi device on starget to check.
1390 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1391 struct scsi_device
*sdev
)
1393 struct scsi_target
*starget
= scsi_target(sdev
);
1396 if (starget
->single_lun
) {
1397 spin_lock_irq(shost
->host_lock
);
1398 if (starget
->starget_sdev_user
&&
1399 starget
->starget_sdev_user
!= sdev
) {
1400 spin_unlock_irq(shost
->host_lock
);
1403 starget
->starget_sdev_user
= sdev
;
1404 spin_unlock_irq(shost
->host_lock
);
1407 if (starget
->can_queue
<= 0)
1410 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1411 if (atomic_read(&starget
->target_blocked
) > 0) {
1416 * unblock after target_blocked iterates to zero
1418 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1421 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1422 "unblocking target at zero depth\n"));
1425 if (busy
>= starget
->can_queue
)
1431 spin_lock_irq(shost
->host_lock
);
1432 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1433 spin_unlock_irq(shost
->host_lock
);
1435 if (starget
->can_queue
> 0)
1436 atomic_dec(&starget
->target_busy
);
1441 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1442 * return 0. We must end up running the queue again whenever 0 is
1443 * returned, else IO can hang.
1445 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1446 struct Scsi_Host
*shost
,
1447 struct scsi_device
*sdev
)
1451 if (scsi_host_in_recovery(shost
))
1454 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1455 if (atomic_read(&shost
->host_blocked
) > 0) {
1460 * unblock after host_blocked iterates to zero
1462 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1466 shost_printk(KERN_INFO
, shost
,
1467 "unblocking host at zero depth\n"));
1470 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1472 if (shost
->host_self_blocked
)
1475 /* We're OK to process the command, so we can't be starved */
1476 if (!list_empty(&sdev
->starved_entry
)) {
1477 spin_lock_irq(shost
->host_lock
);
1478 if (!list_empty(&sdev
->starved_entry
))
1479 list_del_init(&sdev
->starved_entry
);
1480 spin_unlock_irq(shost
->host_lock
);
1486 spin_lock_irq(shost
->host_lock
);
1487 if (list_empty(&sdev
->starved_entry
))
1488 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1489 spin_unlock_irq(shost
->host_lock
);
1491 atomic_dec(&shost
->host_busy
);
1496 * Busy state exporting function for request stacking drivers.
1498 * For efficiency, no lock is taken to check the busy state of
1499 * shost/starget/sdev, since the returned value is not guaranteed and
1500 * may be changed after request stacking drivers call the function,
1501 * regardless of taking lock or not.
1503 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1504 * needs to return 'not busy'. Otherwise, request stacking drivers
1505 * may hold requests forever.
1507 static int scsi_lld_busy(struct request_queue
*q
)
1509 struct scsi_device
*sdev
= q
->queuedata
;
1510 struct Scsi_Host
*shost
;
1512 if (blk_queue_dying(q
))
1518 * Ignore host/starget busy state.
1519 * Since block layer does not have a concept of fairness across
1520 * multiple queues, congestion of host/starget needs to be handled
1523 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1530 * Kill a request for a dead device
1532 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1534 struct scsi_cmnd
*cmd
= req
->special
;
1535 struct scsi_device
*sdev
;
1536 struct scsi_target
*starget
;
1537 struct Scsi_Host
*shost
;
1539 blk_start_request(req
);
1541 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1544 starget
= scsi_target(sdev
);
1546 scsi_init_cmd_errh(cmd
);
1547 cmd
->result
= DID_NO_CONNECT
<< 16;
1548 atomic_inc(&cmd
->device
->iorequest_cnt
);
1551 * SCSI request completion path will do scsi_device_unbusy(),
1552 * bump busy counts. To bump the counters, we need to dance
1553 * with the locks as normal issue path does.
1555 atomic_inc(&sdev
->device_busy
);
1556 atomic_inc(&shost
->host_busy
);
1557 if (starget
->can_queue
> 0)
1558 atomic_inc(&starget
->target_busy
);
1560 blk_complete_request(req
);
1563 static void scsi_softirq_done(struct request
*rq
)
1565 struct scsi_cmnd
*cmd
= rq
->special
;
1566 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1569 INIT_LIST_HEAD(&cmd
->eh_entry
);
1571 atomic_inc(&cmd
->device
->iodone_cnt
);
1573 atomic_inc(&cmd
->device
->ioerr_cnt
);
1575 disposition
= scsi_decide_disposition(cmd
);
1576 if (disposition
!= SUCCESS
&&
1577 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1578 sdev_printk(KERN_ERR
, cmd
->device
,
1579 "timing out command, waited %lus\n",
1581 disposition
= SUCCESS
;
1584 scsi_log_completion(cmd
, disposition
);
1586 switch (disposition
) {
1588 scsi_finish_command(cmd
);
1591 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1593 case ADD_TO_MLQUEUE
:
1594 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1597 scsi_eh_scmd_add(cmd
);
1603 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1604 * @cmd: command block we are dispatching.
1606 * Return: nonzero return request was rejected and device's queue needs to be
1609 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1611 struct Scsi_Host
*host
= cmd
->device
->host
;
1614 atomic_inc(&cmd
->device
->iorequest_cnt
);
1616 /* check if the device is still usable */
1617 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1618 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1619 * returns an immediate error upwards, and signals
1620 * that the device is no longer present */
1621 cmd
->result
= DID_NO_CONNECT
<< 16;
1625 /* Check to see if the scsi lld made this device blocked. */
1626 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1628 * in blocked state, the command is just put back on
1629 * the device queue. The suspend state has already
1630 * blocked the queue so future requests should not
1631 * occur until the device transitions out of the
1634 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1635 "queuecommand : device blocked\n"));
1636 return SCSI_MLQUEUE_DEVICE_BUSY
;
1639 /* Store the LUN value in cmnd, if needed. */
1640 if (cmd
->device
->lun_in_cdb
)
1641 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1642 (cmd
->device
->lun
<< 5 & 0xe0);
1647 * Before we queue this command, check if the command
1648 * length exceeds what the host adapter can handle.
1650 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1651 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1652 "queuecommand : command too long. "
1653 "cdb_size=%d host->max_cmd_len=%d\n",
1654 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1655 cmd
->result
= (DID_ABORT
<< 16);
1659 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1660 cmd
->result
= (DID_NO_CONNECT
<< 16);
1665 trace_scsi_dispatch_cmd_start(cmd
);
1666 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1668 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1669 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1670 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1671 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1673 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1674 "queuecommand : request rejected\n"));
1679 cmd
->scsi_done(cmd
);
1684 * scsi_done - Invoke completion on finished SCSI command.
1685 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1686 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1688 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1689 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1690 * calls blk_complete_request() for further processing.
1692 * This function is interrupt context safe.
1694 static void scsi_done(struct scsi_cmnd
*cmd
)
1696 trace_scsi_dispatch_cmd_done(cmd
);
1697 blk_complete_request(cmd
->request
);
1701 * Function: scsi_request_fn()
1703 * Purpose: Main strategy routine for SCSI.
1705 * Arguments: q - Pointer to actual queue.
1709 * Lock status: IO request lock assumed to be held when called.
1711 static void scsi_request_fn(struct request_queue
*q
)
1712 __releases(q
->queue_lock
)
1713 __acquires(q
->queue_lock
)
1715 struct scsi_device
*sdev
= q
->queuedata
;
1716 struct Scsi_Host
*shost
;
1717 struct scsi_cmnd
*cmd
;
1718 struct request
*req
;
1721 * To start with, we keep looping until the queue is empty, or until
1722 * the host is no longer able to accept any more requests.
1728 * get next queueable request. We do this early to make sure
1729 * that the request is fully prepared even if we cannot
1732 req
= blk_peek_request(q
);
1736 if (unlikely(!scsi_device_online(sdev
))) {
1737 sdev_printk(KERN_ERR
, sdev
,
1738 "rejecting I/O to offline device\n");
1739 scsi_kill_request(req
, q
);
1743 if (!scsi_dev_queue_ready(q
, sdev
))
1747 * Remove the request from the request list.
1749 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1750 blk_start_request(req
);
1752 spin_unlock_irq(q
->queue_lock
);
1754 if (unlikely(cmd
== NULL
)) {
1755 printk(KERN_CRIT
"impossible request in %s.\n"
1756 "please mail a stack trace to "
1757 "linux-scsi@vger.kernel.org\n",
1759 blk_dump_rq_flags(req
, "foo");
1764 * We hit this when the driver is using a host wide
1765 * tag map. For device level tag maps the queue_depth check
1766 * in the device ready fn would prevent us from trying
1767 * to allocate a tag. Since the map is a shared host resource
1768 * we add the dev to the starved list so it eventually gets
1769 * a run when a tag is freed.
1771 if (blk_queue_tagged(q
) && !(req
->rq_flags
& RQF_QUEUED
)) {
1772 spin_lock_irq(shost
->host_lock
);
1773 if (list_empty(&sdev
->starved_entry
))
1774 list_add_tail(&sdev
->starved_entry
,
1775 &shost
->starved_list
);
1776 spin_unlock_irq(shost
->host_lock
);
1780 if (!scsi_target_queue_ready(shost
, sdev
))
1783 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1784 goto host_not_ready
;
1786 if (sdev
->simple_tags
)
1787 cmd
->flags
|= SCMD_TAGGED
;
1789 cmd
->flags
&= ~SCMD_TAGGED
;
1792 * Finally, initialize any error handling parameters, and set up
1793 * the timers for timeouts.
1795 scsi_init_cmd_errh(cmd
);
1798 * Dispatch the command to the low-level driver.
1800 cmd
->scsi_done
= scsi_done
;
1801 rtn
= scsi_dispatch_cmd(cmd
);
1803 scsi_queue_insert(cmd
, rtn
);
1804 spin_lock_irq(q
->queue_lock
);
1807 spin_lock_irq(q
->queue_lock
);
1813 if (scsi_target(sdev
)->can_queue
> 0)
1814 atomic_dec(&scsi_target(sdev
)->target_busy
);
1817 * lock q, handle tag, requeue req, and decrement device_busy. We
1818 * must return with queue_lock held.
1820 * Decrementing device_busy without checking it is OK, as all such
1821 * cases (host limits or settings) should run the queue at some
1824 spin_lock_irq(q
->queue_lock
);
1825 blk_requeue_request(q
, req
);
1826 atomic_dec(&sdev
->device_busy
);
1828 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1829 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1832 static inline int prep_to_mq(int ret
)
1836 return BLK_MQ_RQ_QUEUE_OK
;
1838 return BLK_MQ_RQ_QUEUE_BUSY
;
1840 return BLK_MQ_RQ_QUEUE_ERROR
;
1844 static int scsi_mq_prep_fn(struct request
*req
)
1846 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1847 struct scsi_device
*sdev
= req
->q
->queuedata
;
1848 struct Scsi_Host
*shost
= sdev
->host
;
1849 unsigned char *sense_buf
= cmd
->sense_buffer
;
1850 struct scatterlist
*sg
;
1852 /* zero out the cmd, except for the embedded scsi_request */
1853 memset((char *)cmd
+ sizeof(cmd
->req
), 0,
1854 sizeof(*cmd
) - sizeof(cmd
->req
));
1860 cmd
->sense_buffer
= sense_buf
;
1862 cmd
->tag
= req
->tag
;
1864 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1866 INIT_LIST_HEAD(&cmd
->list
);
1867 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1868 cmd
->jiffies_at_alloc
= jiffies
;
1870 if (shost
->use_cmd_list
) {
1871 spin_lock_irq(&sdev
->list_lock
);
1872 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1873 spin_unlock_irq(&sdev
->list_lock
);
1876 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1877 cmd
->sdb
.table
.sgl
= sg
;
1879 if (scsi_host_get_prot(shost
)) {
1880 cmd
->prot_sdb
= (void *)sg
+
1882 shost
->sg_tablesize
, SG_CHUNK_SIZE
) *
1883 sizeof(struct scatterlist
);
1884 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1886 cmd
->prot_sdb
->table
.sgl
=
1887 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1890 if (blk_bidi_rq(req
)) {
1891 struct request
*next_rq
= req
->next_rq
;
1892 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1894 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1895 bidi_sdb
->table
.sgl
=
1896 (struct scatterlist
*)(bidi_sdb
+ 1);
1898 next_rq
->special
= bidi_sdb
;
1901 blk_mq_start_request(req
);
1903 return scsi_setup_cmnd(sdev
, req
);
1906 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1908 trace_scsi_dispatch_cmd_done(cmd
);
1909 blk_mq_complete_request(cmd
->request
);
1912 static int scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1913 const struct blk_mq_queue_data
*bd
)
1915 struct request
*req
= bd
->rq
;
1916 struct request_queue
*q
= req
->q
;
1917 struct scsi_device
*sdev
= q
->queuedata
;
1918 struct Scsi_Host
*shost
= sdev
->host
;
1919 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1923 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1924 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1927 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1928 if (!get_device(&sdev
->sdev_gendev
))
1931 if (!scsi_dev_queue_ready(q
, sdev
))
1932 goto out_put_device
;
1933 if (!scsi_target_queue_ready(shost
, sdev
))
1934 goto out_dec_device_busy
;
1935 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1936 goto out_dec_target_busy
;
1938 if (!(req
->rq_flags
& RQF_DONTPREP
)) {
1939 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1940 if (ret
!= BLK_MQ_RQ_QUEUE_OK
)
1941 goto out_dec_host_busy
;
1942 req
->rq_flags
|= RQF_DONTPREP
;
1944 blk_mq_start_request(req
);
1947 if (sdev
->simple_tags
)
1948 cmd
->flags
|= SCMD_TAGGED
;
1950 cmd
->flags
&= ~SCMD_TAGGED
;
1952 scsi_init_cmd_errh(cmd
);
1953 cmd
->scsi_done
= scsi_mq_done
;
1955 reason
= scsi_dispatch_cmd(cmd
);
1957 scsi_set_blocked(cmd
, reason
);
1958 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1959 goto out_dec_host_busy
;
1962 return BLK_MQ_RQ_QUEUE_OK
;
1965 atomic_dec(&shost
->host_busy
);
1966 out_dec_target_busy
:
1967 if (scsi_target(sdev
)->can_queue
> 0)
1968 atomic_dec(&scsi_target(sdev
)->target_busy
);
1969 out_dec_device_busy
:
1970 atomic_dec(&sdev
->device_busy
);
1972 put_device(&sdev
->sdev_gendev
);
1975 case BLK_MQ_RQ_QUEUE_BUSY
:
1976 if (atomic_read(&sdev
->device_busy
) == 0 &&
1977 !scsi_device_blocked(sdev
))
1978 blk_mq_delay_run_hw_queue(hctx
, SCSI_QUEUE_DELAY
);
1980 case BLK_MQ_RQ_QUEUE_ERROR
:
1982 * Make sure to release all allocated ressources when
1983 * we hit an error, as we will never see this command
1986 if (req
->rq_flags
& RQF_DONTPREP
)
1987 scsi_mq_uninit_cmd(cmd
);
1995 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
1999 return BLK_EH_RESET_TIMER
;
2000 return scsi_times_out(req
);
2003 static int scsi_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2004 unsigned int hctx_idx
, unsigned int numa_node
)
2006 struct Scsi_Host
*shost
= set
->driver_data
;
2007 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2010 scsi_alloc_sense_buffer(shost
, GFP_KERNEL
, numa_node
);
2011 if (!cmd
->sense_buffer
)
2013 cmd
->req
.sense
= cmd
->sense_buffer
;
2017 static void scsi_exit_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2018 unsigned int hctx_idx
)
2020 struct Scsi_Host
*shost
= set
->driver_data
;
2021 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2023 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2026 static int scsi_map_queues(struct blk_mq_tag_set
*set
)
2028 struct Scsi_Host
*shost
= container_of(set
, struct Scsi_Host
, tag_set
);
2030 if (shost
->hostt
->map_queues
)
2031 return shost
->hostt
->map_queues(shost
);
2032 return blk_mq_map_queues(set
);
2035 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2037 struct device
*host_dev
;
2038 u64 bounce_limit
= 0xffffffff;
2040 if (shost
->unchecked_isa_dma
)
2041 return BLK_BOUNCE_ISA
;
2043 * Platforms with virtual-DMA translation
2044 * hardware have no practical limit.
2046 if (!PCI_DMA_BUS_IS_PHYS
)
2047 return BLK_BOUNCE_ANY
;
2049 host_dev
= scsi_get_device(shost
);
2050 if (host_dev
&& host_dev
->dma_mask
)
2051 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2053 return bounce_limit
;
2056 void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2058 struct device
*dev
= shost
->dma_dev
;
2061 * this limit is imposed by hardware restrictions
2063 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
2066 if (scsi_host_prot_dma(shost
)) {
2067 shost
->sg_prot_tablesize
=
2068 min_not_zero(shost
->sg_prot_tablesize
,
2069 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
2070 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
2071 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
2074 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
2075 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
2076 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
2077 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
2079 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2081 if (!shost
->use_clustering
)
2082 q
->limits
.cluster
= 0;
2085 * set a reasonable default alignment on word boundaries: the
2086 * host and device may alter it using
2087 * blk_queue_update_dma_alignment() later.
2089 blk_queue_dma_alignment(q
, 0x03);
2091 EXPORT_SYMBOL_GPL(__scsi_init_queue
);
2093 static int scsi_init_rq(struct request_queue
*q
, struct request
*rq
, gfp_t gfp
)
2095 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2096 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2098 memset(cmd
, 0, sizeof(*cmd
));
2100 cmd
->sense_buffer
= scsi_alloc_sense_buffer(shost
, gfp
, NUMA_NO_NODE
);
2101 if (!cmd
->sense_buffer
)
2103 cmd
->req
.sense
= cmd
->sense_buffer
;
2105 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
2106 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp
);
2108 goto fail_free_sense
;
2114 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2119 static void scsi_exit_rq(struct request_queue
*q
, struct request
*rq
)
2121 struct Scsi_Host
*shost
= q
->rq_alloc_data
;
2122 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2125 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
2126 scsi_free_sense_buffer(shost
, cmd
->sense_buffer
);
2129 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
2131 struct Scsi_Host
*shost
= sdev
->host
;
2132 struct request_queue
*q
;
2134 q
= blk_alloc_queue_node(GFP_KERNEL
, NUMA_NO_NODE
);
2137 q
->cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
2138 q
->rq_alloc_data
= shost
;
2139 q
->request_fn
= scsi_request_fn
;
2140 q
->init_rq_fn
= scsi_init_rq
;
2141 q
->exit_rq_fn
= scsi_exit_rq
;
2143 if (blk_init_allocated_queue(q
) < 0) {
2144 blk_cleanup_queue(q
);
2148 __scsi_init_queue(shost
, q
);
2149 blk_queue_prep_rq(q
, scsi_prep_fn
);
2150 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2151 blk_queue_softirq_done(q
, scsi_softirq_done
);
2152 blk_queue_rq_timed_out(q
, scsi_times_out
);
2153 blk_queue_lld_busy(q
, scsi_lld_busy
);
2157 static const struct blk_mq_ops scsi_mq_ops
= {
2158 .queue_rq
= scsi_queue_rq
,
2159 .complete
= scsi_softirq_done
,
2160 .timeout
= scsi_timeout
,
2161 #ifdef CONFIG_BLK_DEBUG_FS
2162 .show_rq
= scsi_show_rq
,
2164 .init_request
= scsi_init_request
,
2165 .exit_request
= scsi_exit_request
,
2166 .map_queues
= scsi_map_queues
,
2169 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2171 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2172 if (IS_ERR(sdev
->request_queue
))
2175 sdev
->request_queue
->queuedata
= sdev
;
2176 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2177 return sdev
->request_queue
;
2180 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2182 unsigned int cmd_size
, sgl_size
, tbl_size
;
2184 tbl_size
= shost
->sg_tablesize
;
2185 if (tbl_size
> SG_CHUNK_SIZE
)
2186 tbl_size
= SG_CHUNK_SIZE
;
2187 sgl_size
= tbl_size
* sizeof(struct scatterlist
);
2188 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2189 if (scsi_host_get_prot(shost
))
2190 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2192 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2193 shost
->tag_set
.ops
= &scsi_mq_ops
;
2194 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2195 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2196 shost
->tag_set
.cmd_size
= cmd_size
;
2197 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2198 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2199 shost
->tag_set
.flags
|=
2200 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2201 shost
->tag_set
.driver_data
= shost
;
2203 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2206 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2208 blk_mq_free_tag_set(&shost
->tag_set
);
2212 * scsi_device_from_queue - return sdev associated with a request_queue
2213 * @q: The request queue to return the sdev from
2215 * Return the sdev associated with a request queue or NULL if the
2216 * request_queue does not reference a SCSI device.
2218 struct scsi_device
*scsi_device_from_queue(struct request_queue
*q
)
2220 struct scsi_device
*sdev
= NULL
;
2223 if (q
->mq_ops
== &scsi_mq_ops
)
2224 sdev
= q
->queuedata
;
2225 } else if (q
->request_fn
== scsi_request_fn
)
2226 sdev
= q
->queuedata
;
2227 if (!sdev
|| !get_device(&sdev
->sdev_gendev
))
2232 EXPORT_SYMBOL_GPL(scsi_device_from_queue
);
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: outpout pointer for decoded sense information.
2502 * Returns zero if unsuccessful or an error if TUR failed. For
2503 * removable media, UNIT_ATTENTION sets ->changed flag.
2506 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2507 struct scsi_sense_hdr
*sshdr
)
2510 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2514 /* try to eat the UNIT_ATTENTION if there are enough retries */
2516 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2517 timeout
, retries
, NULL
);
2518 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2519 sshdr
->sense_key
== UNIT_ATTENTION
)
2521 } while (scsi_sense_valid(sshdr
) &&
2522 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2526 EXPORT_SYMBOL(scsi_test_unit_ready
);
2529 * scsi_device_set_state - Take the given device through the device state model.
2530 * @sdev: scsi device to change the state of.
2531 * @state: state to change to.
2533 * Returns zero if unsuccessful or an error if the requested
2534 * transition is illegal.
2537 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2539 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2541 if (state
== oldstate
)
2547 case SDEV_CREATED_BLOCK
:
2558 case SDEV_TRANSPORT_OFFLINE
:
2571 case SDEV_TRANSPORT_OFFLINE
:
2579 case SDEV_TRANSPORT_OFFLINE
:
2594 case SDEV_CREATED_BLOCK
:
2601 case SDEV_CREATED_BLOCK
:
2616 case SDEV_TRANSPORT_OFFLINE
:
2629 case SDEV_TRANSPORT_OFFLINE
:
2631 case SDEV_CREATED_BLOCK
:
2639 sdev
->sdev_state
= state
;
2643 SCSI_LOG_ERROR_RECOVERY(1,
2644 sdev_printk(KERN_ERR
, sdev
,
2645 "Illegal state transition %s->%s",
2646 scsi_device_state_name(oldstate
),
2647 scsi_device_state_name(state
))
2651 EXPORT_SYMBOL(scsi_device_set_state
);
2654 * sdev_evt_emit - emit a single SCSI device uevent
2655 * @sdev: associated SCSI device
2656 * @evt: event to emit
2658 * Send a single uevent (scsi_event) to the associated scsi_device.
2660 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2665 switch (evt
->evt_type
) {
2666 case SDEV_EVT_MEDIA_CHANGE
:
2667 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2669 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2670 scsi_rescan_device(&sdev
->sdev_gendev
);
2671 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2673 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2674 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2676 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2677 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2679 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2680 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2682 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2683 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2685 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2686 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2695 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2699 * sdev_evt_thread - send a uevent for each scsi event
2700 * @work: work struct for scsi_device
2702 * Dispatch queued events to their associated scsi_device kobjects
2705 void scsi_evt_thread(struct work_struct
*work
)
2707 struct scsi_device
*sdev
;
2708 enum scsi_device_event evt_type
;
2709 LIST_HEAD(event_list
);
2711 sdev
= container_of(work
, struct scsi_device
, event_work
);
2713 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2714 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2715 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2718 struct scsi_event
*evt
;
2719 struct list_head
*this, *tmp
;
2720 unsigned long flags
;
2722 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2723 list_splice_init(&sdev
->event_list
, &event_list
);
2724 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2726 if (list_empty(&event_list
))
2729 list_for_each_safe(this, tmp
, &event_list
) {
2730 evt
= list_entry(this, struct scsi_event
, node
);
2731 list_del(&evt
->node
);
2732 scsi_evt_emit(sdev
, evt
);
2739 * sdev_evt_send - send asserted event to uevent thread
2740 * @sdev: scsi_device event occurred on
2741 * @evt: event to send
2743 * Assert scsi device event asynchronously.
2745 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2747 unsigned long flags
;
2750 /* FIXME: currently this check eliminates all media change events
2751 * for polled devices. Need to update to discriminate between AN
2752 * and polled events */
2753 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2759 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2760 list_add_tail(&evt
->node
, &sdev
->event_list
);
2761 schedule_work(&sdev
->event_work
);
2762 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2764 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2767 * sdev_evt_alloc - allocate a new scsi event
2768 * @evt_type: type of event to allocate
2769 * @gfpflags: GFP flags for allocation
2771 * Allocates and returns a new scsi_event.
2773 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2776 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2780 evt
->evt_type
= evt_type
;
2781 INIT_LIST_HEAD(&evt
->node
);
2783 /* evt_type-specific initialization, if any */
2785 case SDEV_EVT_MEDIA_CHANGE
:
2786 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2787 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2788 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2789 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2790 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2791 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2799 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2802 * sdev_evt_send_simple - send asserted event to uevent thread
2803 * @sdev: scsi_device event occurred on
2804 * @evt_type: type of event to send
2805 * @gfpflags: GFP flags for allocation
2807 * Assert scsi device event asynchronously, given an event type.
2809 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2810 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2812 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2814 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2819 sdev_evt_send(sdev
, evt
);
2821 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2824 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2825 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2827 static int scsi_request_fn_active(struct scsi_device
*sdev
)
2829 struct request_queue
*q
= sdev
->request_queue
;
2830 int request_fn_active
;
2832 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2834 spin_lock_irq(q
->queue_lock
);
2835 request_fn_active
= q
->request_fn_active
;
2836 spin_unlock_irq(q
->queue_lock
);
2838 return request_fn_active
;
2842 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2843 * @sdev: SCSI device pointer.
2845 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2846 * invoked from scsi_request_fn() have finished.
2848 static void scsi_wait_for_queuecommand(struct scsi_device
*sdev
)
2850 WARN_ON_ONCE(sdev
->host
->use_blk_mq
);
2852 while (scsi_request_fn_active(sdev
))
2857 * scsi_device_quiesce - Block user issued commands.
2858 * @sdev: scsi device to quiesce.
2860 * This works by trying to transition to the SDEV_QUIESCE state
2861 * (which must be a legal transition). When the device is in this
2862 * state, only special requests will be accepted, all others will
2863 * be deferred. Since special requests may also be requeued requests,
2864 * a successful return doesn't guarantee the device will be
2865 * totally quiescent.
2867 * Must be called with user context, may sleep.
2869 * Returns zero if unsuccessful or an error if not.
2872 scsi_device_quiesce(struct scsi_device
*sdev
)
2874 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2878 scsi_run_queue(sdev
->request_queue
);
2879 while (atomic_read(&sdev
->device_busy
)) {
2880 msleep_interruptible(200);
2881 scsi_run_queue(sdev
->request_queue
);
2885 EXPORT_SYMBOL(scsi_device_quiesce
);
2888 * scsi_device_resume - Restart user issued commands to a quiesced device.
2889 * @sdev: scsi device to resume.
2891 * Moves the device from quiesced back to running and restarts the
2894 * Must be called with user context, may sleep.
2896 void scsi_device_resume(struct scsi_device
*sdev
)
2898 /* check if the device state was mutated prior to resume, and if
2899 * so assume the state is being managed elsewhere (for example
2900 * device deleted during suspend)
2902 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2903 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2905 scsi_run_queue(sdev
->request_queue
);
2907 EXPORT_SYMBOL(scsi_device_resume
);
2910 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2912 scsi_device_quiesce(sdev
);
2916 scsi_target_quiesce(struct scsi_target
*starget
)
2918 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2920 EXPORT_SYMBOL(scsi_target_quiesce
);
2923 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2925 scsi_device_resume(sdev
);
2929 scsi_target_resume(struct scsi_target
*starget
)
2931 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2933 EXPORT_SYMBOL(scsi_target_resume
);
2936 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2937 * @sdev: device to block
2938 * @wait: Whether or not to wait until ongoing .queuecommand() /
2939 * .queue_rq() calls have finished.
2941 * Block request made by scsi lld's to temporarily stop all
2942 * scsi commands on the specified device. May sleep.
2944 * Returns zero if successful or error if not
2947 * This routine transitions the device to the SDEV_BLOCK state
2948 * (which must be a legal transition). When the device is in this
2949 * state, all commands are deferred until the scsi lld reenables
2950 * the device with scsi_device_unblock or device_block_tmo fires.
2952 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2953 * scsi_internal_device_block() has blocked a SCSI device and also
2954 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2957 scsi_internal_device_block(struct scsi_device
*sdev
, bool wait
)
2959 struct request_queue
*q
= sdev
->request_queue
;
2960 unsigned long flags
;
2963 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2965 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2972 * The device has transitioned to SDEV_BLOCK. Stop the
2973 * block layer from calling the midlayer with this device's
2978 blk_mq_quiesce_queue(q
);
2980 blk_mq_stop_hw_queues(q
);
2982 spin_lock_irqsave(q
->queue_lock
, flags
);
2984 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2986 scsi_wait_for_queuecommand(sdev
);
2991 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2994 * scsi_internal_device_unblock - resume a device after a block request
2995 * @sdev: device to resume
2996 * @new_state: state to set devices to after unblocking
2998 * Called by scsi lld's or the midlayer to restart the device queue
2999 * for the previously suspended scsi device. Called from interrupt or
3000 * normal process context.
3002 * Returns zero if successful or error if not.
3005 * This routine transitions the device to the SDEV_RUNNING state
3006 * or to one of the offline states (which must be a legal transition)
3007 * allowing the midlayer to goose the queue for this device.
3010 scsi_internal_device_unblock(struct scsi_device
*sdev
,
3011 enum scsi_device_state new_state
)
3013 struct request_queue
*q
= sdev
->request_queue
;
3014 unsigned long flags
;
3017 * Try to transition the scsi device to SDEV_RUNNING or one of the
3018 * offlined states and goose the device queue if successful.
3020 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
3021 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
3022 sdev
->sdev_state
= new_state
;
3023 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
3024 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3025 new_state
== SDEV_OFFLINE
)
3026 sdev
->sdev_state
= new_state
;
3028 sdev
->sdev_state
= SDEV_CREATED
;
3029 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
3030 sdev
->sdev_state
!= SDEV_OFFLINE
)
3034 blk_mq_start_stopped_hw_queues(q
, false);
3036 spin_lock_irqsave(q
->queue_lock
, flags
);
3038 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3043 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
3046 device_block(struct scsi_device
*sdev
, void *data
)
3048 scsi_internal_device_block(sdev
, true);
3052 target_block(struct device
*dev
, void *data
)
3054 if (scsi_is_target_device(dev
))
3055 starget_for_each_device(to_scsi_target(dev
), NULL
,
3061 scsi_target_block(struct device
*dev
)
3063 if (scsi_is_target_device(dev
))
3064 starget_for_each_device(to_scsi_target(dev
), NULL
,
3067 device_for_each_child(dev
, NULL
, target_block
);
3069 EXPORT_SYMBOL_GPL(scsi_target_block
);
3072 device_unblock(struct scsi_device
*sdev
, void *data
)
3074 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3078 target_unblock(struct device
*dev
, void *data
)
3080 if (scsi_is_target_device(dev
))
3081 starget_for_each_device(to_scsi_target(dev
), data
,
3087 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3089 if (scsi_is_target_device(dev
))
3090 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3093 device_for_each_child(dev
, &new_state
, target_unblock
);
3095 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3098 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3099 * @sgl: scatter-gather list
3100 * @sg_count: number of segments in sg
3101 * @offset: offset in bytes into sg, on return offset into the mapped area
3102 * @len: bytes to map, on return number of bytes mapped
3104 * Returns virtual address of the start of the mapped page
3106 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3107 size_t *offset
, size_t *len
)
3110 size_t sg_len
= 0, len_complete
= 0;
3111 struct scatterlist
*sg
;
3114 WARN_ON(!irqs_disabled());
3116 for_each_sg(sgl
, sg
, sg_count
, i
) {
3117 len_complete
= sg_len
; /* Complete sg-entries */
3118 sg_len
+= sg
->length
;
3119 if (sg_len
> *offset
)
3123 if (unlikely(i
== sg_count
)) {
3124 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3126 __func__
, sg_len
, *offset
, sg_count
);
3131 /* Offset starting from the beginning of first page in this sg-entry */
3132 *offset
= *offset
- len_complete
+ sg
->offset
;
3134 /* Assumption: contiguous pages can be accessed as "page + i" */
3135 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3136 *offset
&= ~PAGE_MASK
;
3138 /* Bytes in this sg-entry from *offset to the end of the page */
3139 sg_len
= PAGE_SIZE
- *offset
;
3143 return kmap_atomic(page
);
3145 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3148 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3149 * @virt: virtual address to be unmapped
3151 void scsi_kunmap_atomic_sg(void *virt
)
3153 kunmap_atomic(virt
);
3155 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3157 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3159 atomic_inc(&sdev
->disk_events_disable_depth
);
3161 EXPORT_SYMBOL(sdev_disable_disk_events
);
3163 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3165 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3167 atomic_dec(&sdev
->disk_events_disable_depth
);
3169 EXPORT_SYMBOL(sdev_enable_disk_events
);
3172 * scsi_vpd_lun_id - return a unique device identification
3173 * @sdev: SCSI device
3174 * @id: buffer for the identification
3175 * @id_len: length of the buffer
3177 * Copies a unique device identification into @id based
3178 * on the information in the VPD page 0x83 of the device.
3179 * The string will be formatted as a SCSI name string.
3181 * Returns the length of the identification or error on failure.
3182 * If the identifier is longer than the supplied buffer the actual
3183 * identifier length is returned and the buffer is not zero-padded.
3185 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3187 u8 cur_id_type
= 0xff;
3189 unsigned char *d
, *cur_id_str
;
3190 unsigned char __rcu
*vpd_pg83
;
3191 int id_size
= -EINVAL
;
3194 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3201 * Look for the correct descriptor.
3202 * Order of preference for lun descriptor:
3203 * - SCSI name string
3204 * - NAA IEEE Registered Extended
3205 * - EUI-64 based 16-byte
3206 * - EUI-64 based 12-byte
3207 * - NAA IEEE Registered
3208 * - NAA IEEE Extended
3210 * as longer descriptors reduce the likelyhood
3211 * of identification clashes.
3214 /* The id string must be at least 20 bytes + terminating NULL byte */
3220 memset(id
, 0, id_len
);
3222 while (d
< vpd_pg83
+ sdev
->vpd_pg83_len
) {
3223 /* Skip designators not referring to the LUN */
3224 if ((d
[1] & 0x30) != 0x00)
3227 switch (d
[1] & 0xf) {
3230 if (cur_id_size
> d
[3])
3232 /* Prefer anything */
3233 if (cur_id_type
> 0x01 && cur_id_type
!= 0xff)
3236 if (cur_id_size
+ 4 > id_len
)
3237 cur_id_size
= id_len
- 4;
3239 cur_id_type
= d
[1] & 0xf;
3240 id_size
= snprintf(id
, id_len
, "t10.%*pE",
3241 cur_id_size
, cur_id_str
);
3245 if (cur_id_size
> d
[3])
3247 /* Prefer NAA IEEE Registered Extended */
3248 if (cur_id_type
== 0x3 &&
3249 cur_id_size
== d
[3])
3253 cur_id_type
= d
[1] & 0xf;
3254 switch (cur_id_size
) {
3256 id_size
= snprintf(id
, id_len
,
3261 id_size
= snprintf(id
, id_len
,
3266 id_size
= snprintf(id
, id_len
,
3277 if (cur_id_size
> d
[3])
3281 cur_id_type
= d
[1] & 0xf;
3282 switch (cur_id_size
) {
3284 id_size
= snprintf(id
, id_len
,
3289 id_size
= snprintf(id
, id_len
,
3299 /* SCSI name string */
3300 if (cur_id_size
+ 4 > d
[3])
3302 /* Prefer others for truncated descriptor */
3303 if (cur_id_size
&& d
[3] > id_len
)
3305 cur_id_size
= id_size
= d
[3];
3307 cur_id_type
= d
[1] & 0xf;
3308 if (cur_id_size
>= id_len
)
3309 cur_id_size
= id_len
- 1;
3310 memcpy(id
, cur_id_str
, cur_id_size
);
3311 /* Decrease priority for truncated descriptor */
3312 if (cur_id_size
!= id_size
)
3325 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3328 * scsi_vpd_tpg_id - return a target port group identifier
3329 * @sdev: SCSI device
3331 * Returns the Target Port Group identifier from the information
3332 * froom VPD page 0x83 of the device.
3334 * Returns the identifier or error on failure.
3336 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3339 unsigned char __rcu
*vpd_pg83
;
3340 int group_id
= -EAGAIN
, rel_port
= -1;
3343 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3349 d
= sdev
->vpd_pg83
+ 4;
3350 while (d
< sdev
->vpd_pg83
+ sdev
->vpd_pg83_len
) {
3351 switch (d
[1] & 0xf) {
3353 /* Relative target port */
3354 rel_port
= get_unaligned_be16(&d
[6]);
3357 /* Target port group */
3358 group_id
= get_unaligned_be16(&d
[6]);
3367 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3372 EXPORT_SYMBOL(scsi_vpd_tpg_id
);