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/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/init.h>
20 #include <linux/pci.h>
21 #include <linux/delay.h>
22 #include <linux/hardirq.h>
23 #include <linux/scatterlist.h>
24 #include <linux/blk-mq.h>
25 #include <linux/ratelimit.h>
26 #include <asm/unaligned.h>
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_driver.h>
33 #include <scsi/scsi_eh.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_dh.h>
37 #include <trace/events/scsi.h>
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
43 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
44 #define SG_MEMPOOL_SIZE 2
46 struct scsi_host_sg_pool
{
49 struct kmem_cache
*slab
;
53 #define SP(x) { .size = x, "sgpool-" __stringify(x) }
54 #if (SCSI_MAX_SG_SEGMENTS < 32)
55 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
57 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
60 #if (SCSI_MAX_SG_SEGMENTS > 32)
62 #if (SCSI_MAX_SG_SEGMENTS > 64)
64 #if (SCSI_MAX_SG_SEGMENTS > 128)
66 #if (SCSI_MAX_SG_SEGMENTS > 256)
67 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
72 SP(SCSI_MAX_SG_SEGMENTS
)
76 struct kmem_cache
*scsi_sdb_cache
;
79 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
80 * not change behaviour from the previous unplug mechanism, experimentation
81 * may prove this needs changing.
83 #define SCSI_QUEUE_DELAY 3
86 scsi_set_blocked(struct scsi_cmnd
*cmd
, int reason
)
88 struct Scsi_Host
*host
= cmd
->device
->host
;
89 struct scsi_device
*device
= cmd
->device
;
90 struct scsi_target
*starget
= scsi_target(device
);
93 * Set the appropriate busy bit for the device/host.
95 * If the host/device isn't busy, assume that something actually
96 * completed, and that we should be able to queue a command now.
98 * Note that the prior mid-layer assumption that any host could
99 * always queue at least one command is now broken. The mid-layer
100 * will implement a user specifiable stall (see
101 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
102 * if a command is requeued with no other commands outstanding
103 * either for the device or for the host.
106 case SCSI_MLQUEUE_HOST_BUSY
:
107 atomic_set(&host
->host_blocked
, host
->max_host_blocked
);
109 case SCSI_MLQUEUE_DEVICE_BUSY
:
110 case SCSI_MLQUEUE_EH_RETRY
:
111 atomic_set(&device
->device_blocked
,
112 device
->max_device_blocked
);
114 case SCSI_MLQUEUE_TARGET_BUSY
:
115 atomic_set(&starget
->target_blocked
,
116 starget
->max_target_blocked
);
121 static void scsi_mq_requeue_cmd(struct scsi_cmnd
*cmd
)
123 struct scsi_device
*sdev
= cmd
->device
;
124 struct request_queue
*q
= cmd
->request
->q
;
126 blk_mq_requeue_request(cmd
->request
);
127 blk_mq_kick_requeue_list(q
);
128 put_device(&sdev
->sdev_gendev
);
132 * __scsi_queue_insert - private queue insertion
133 * @cmd: The SCSI command being requeued
134 * @reason: The reason for the requeue
135 * @unbusy: Whether the queue should be unbusied
137 * This is a private queue insertion. The public interface
138 * scsi_queue_insert() always assumes the queue should be unbusied
139 * because it's always called before the completion. This function is
140 * for a requeue after completion, which should only occur in this
143 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
145 struct scsi_device
*device
= cmd
->device
;
146 struct request_queue
*q
= device
->request_queue
;
149 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO
, cmd
,
150 "Inserting command %p into mlqueue\n", cmd
));
152 scsi_set_blocked(cmd
, reason
);
155 * Decrement the counters, since these commands are no longer
156 * active on the host/device.
159 scsi_device_unbusy(device
);
162 * Requeue this command. It will go before all other commands
163 * that are already in the queue. Schedule requeue work under
164 * lock such that the kblockd_schedule_work() call happens
165 * before blk_cleanup_queue() finishes.
169 scsi_mq_requeue_cmd(cmd
);
172 spin_lock_irqsave(q
->queue_lock
, flags
);
173 blk_requeue_request(q
, cmd
->request
);
174 kblockd_schedule_work(&device
->requeue_work
);
175 spin_unlock_irqrestore(q
->queue_lock
, flags
);
179 * Function: scsi_queue_insert()
181 * Purpose: Insert a command in the midlevel queue.
183 * Arguments: cmd - command that we are adding to queue.
184 * reason - why we are inserting command to queue.
186 * Lock status: Assumed that lock is not held upon entry.
190 * Notes: We do this for one of two cases. Either the host is busy
191 * and it cannot accept any more commands for the time being,
192 * or the device returned QUEUE_FULL and can accept no more
194 * Notes: This could be called either from an interrupt context or a
195 * normal process context.
197 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
199 __scsi_queue_insert(cmd
, reason
, 1);
202 * scsi_execute - insert request and wait for the result
205 * @data_direction: data direction
206 * @buffer: data buffer
207 * @bufflen: len of buffer
208 * @sense: optional sense buffer
209 * @timeout: request timeout in seconds
210 * @retries: number of times to retry request
211 * @flags: or into request flags;
212 * @resid: optional residual length
214 * returns the req->errors value which is the scsi_cmnd result
217 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
218 int data_direction
, void *buffer
, unsigned bufflen
,
219 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
223 int write
= (data_direction
== DMA_TO_DEVICE
);
224 int ret
= DRIVER_ERROR
<< 24;
226 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_RECLAIM
);
229 blk_rq_set_block_pc(req
);
231 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
232 buffer
, bufflen
, __GFP_RECLAIM
))
235 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
236 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
239 req
->retries
= retries
;
240 req
->timeout
= timeout
;
241 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
244 * head injection *required* here otherwise quiesce won't work
246 blk_execute_rq(req
->q
, NULL
, req
, 1);
249 * Some devices (USB mass-storage in particular) may transfer
250 * garbage data together with a residue indicating that the data
251 * is invalid. Prevent the garbage from being misinterpreted
252 * and prevent security leaks by zeroing out the excess data.
254 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
255 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
258 *resid
= req
->resid_len
;
261 blk_put_request(req
);
265 EXPORT_SYMBOL(scsi_execute
);
267 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
268 int data_direction
, void *buffer
, unsigned bufflen
,
269 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
270 int *resid
, u64 flags
)
276 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
278 return DRIVER_ERROR
<< 24;
280 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
281 sense
, timeout
, retries
, flags
, resid
);
283 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
288 EXPORT_SYMBOL(scsi_execute_req_flags
);
291 * Function: scsi_init_cmd_errh()
293 * Purpose: Initialize cmd fields related to error handling.
295 * Arguments: cmd - command that is ready to be queued.
297 * Notes: This function has the job of initializing a number of
298 * fields related to error handling. Typically this will
299 * be called once for each command, as required.
301 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
303 cmd
->serial_number
= 0;
304 scsi_set_resid(cmd
, 0);
305 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
306 if (cmd
->cmd_len
== 0)
307 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
310 void scsi_device_unbusy(struct scsi_device
*sdev
)
312 struct Scsi_Host
*shost
= sdev
->host
;
313 struct scsi_target
*starget
= scsi_target(sdev
);
316 atomic_dec(&shost
->host_busy
);
317 if (starget
->can_queue
> 0)
318 atomic_dec(&starget
->target_busy
);
320 if (unlikely(scsi_host_in_recovery(shost
) &&
321 (shost
->host_failed
|| shost
->host_eh_scheduled
))) {
322 spin_lock_irqsave(shost
->host_lock
, flags
);
323 scsi_eh_wakeup(shost
);
324 spin_unlock_irqrestore(shost
->host_lock
, flags
);
327 atomic_dec(&sdev
->device_busy
);
330 static void scsi_kick_queue(struct request_queue
*q
)
333 blk_mq_start_hw_queues(q
);
339 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
340 * and call blk_run_queue for all the scsi_devices on the target -
341 * including current_sdev first.
343 * Called with *no* scsi locks held.
345 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
347 struct Scsi_Host
*shost
= current_sdev
->host
;
348 struct scsi_device
*sdev
, *tmp
;
349 struct scsi_target
*starget
= scsi_target(current_sdev
);
352 spin_lock_irqsave(shost
->host_lock
, flags
);
353 starget
->starget_sdev_user
= NULL
;
354 spin_unlock_irqrestore(shost
->host_lock
, flags
);
357 * Call blk_run_queue for all LUNs on the target, starting with
358 * current_sdev. We race with others (to set starget_sdev_user),
359 * but in most cases, we will be first. Ideally, each LU on the
360 * target would get some limited time or requests on the target.
362 scsi_kick_queue(current_sdev
->request_queue
);
364 spin_lock_irqsave(shost
->host_lock
, flags
);
365 if (starget
->starget_sdev_user
)
367 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
368 same_target_siblings
) {
369 if (sdev
== current_sdev
)
371 if (scsi_device_get(sdev
))
374 spin_unlock_irqrestore(shost
->host_lock
, flags
);
375 scsi_kick_queue(sdev
->request_queue
);
376 spin_lock_irqsave(shost
->host_lock
, flags
);
378 scsi_device_put(sdev
);
381 spin_unlock_irqrestore(shost
->host_lock
, flags
);
384 static inline bool scsi_device_is_busy(struct scsi_device
*sdev
)
386 if (atomic_read(&sdev
->device_busy
) >= sdev
->queue_depth
)
388 if (atomic_read(&sdev
->device_blocked
) > 0)
393 static inline bool scsi_target_is_busy(struct scsi_target
*starget
)
395 if (starget
->can_queue
> 0) {
396 if (atomic_read(&starget
->target_busy
) >= starget
->can_queue
)
398 if (atomic_read(&starget
->target_blocked
) > 0)
404 static inline bool scsi_host_is_busy(struct Scsi_Host
*shost
)
406 if (shost
->can_queue
> 0 &&
407 atomic_read(&shost
->host_busy
) >= shost
->can_queue
)
409 if (atomic_read(&shost
->host_blocked
) > 0)
411 if (shost
->host_self_blocked
)
416 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
418 LIST_HEAD(starved_list
);
419 struct scsi_device
*sdev
;
422 spin_lock_irqsave(shost
->host_lock
, flags
);
423 list_splice_init(&shost
->starved_list
, &starved_list
);
425 while (!list_empty(&starved_list
)) {
426 struct request_queue
*slq
;
429 * As long as shost is accepting commands and we have
430 * starved queues, call blk_run_queue. scsi_request_fn
431 * drops the queue_lock and can add us back to the
434 * host_lock protects the starved_list and starved_entry.
435 * scsi_request_fn must get the host_lock before checking
436 * or modifying starved_list or starved_entry.
438 if (scsi_host_is_busy(shost
))
441 sdev
= list_entry(starved_list
.next
,
442 struct scsi_device
, starved_entry
);
443 list_del_init(&sdev
->starved_entry
);
444 if (scsi_target_is_busy(scsi_target(sdev
))) {
445 list_move_tail(&sdev
->starved_entry
,
446 &shost
->starved_list
);
451 * Once we drop the host lock, a racing scsi_remove_device()
452 * call may remove the sdev from the starved list and destroy
453 * it and the queue. Mitigate by taking a reference to the
454 * queue and never touching the sdev again after we drop the
455 * host lock. Note: if __scsi_remove_device() invokes
456 * blk_cleanup_queue() before the queue is run from this
457 * function then blk_run_queue() will return immediately since
458 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
460 slq
= sdev
->request_queue
;
461 if (!blk_get_queue(slq
))
463 spin_unlock_irqrestore(shost
->host_lock
, flags
);
465 scsi_kick_queue(slq
);
468 spin_lock_irqsave(shost
->host_lock
, flags
);
470 /* put any unprocessed entries back */
471 list_splice(&starved_list
, &shost
->starved_list
);
472 spin_unlock_irqrestore(shost
->host_lock
, flags
);
476 * Function: scsi_run_queue()
478 * Purpose: Select a proper request queue to serve next
480 * Arguments: q - last request's queue
484 * Notes: The previous command was completely finished, start
485 * a new one if possible.
487 static void scsi_run_queue(struct request_queue
*q
)
489 struct scsi_device
*sdev
= q
->queuedata
;
491 if (scsi_target(sdev
)->single_lun
)
492 scsi_single_lun_run(sdev
);
493 if (!list_empty(&sdev
->host
->starved_list
))
494 scsi_starved_list_run(sdev
->host
);
497 blk_mq_start_stopped_hw_queues(q
, false);
502 void scsi_requeue_run_queue(struct work_struct
*work
)
504 struct scsi_device
*sdev
;
505 struct request_queue
*q
;
507 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
508 q
= sdev
->request_queue
;
513 * Function: scsi_requeue_command()
515 * Purpose: Handle post-processing of completed commands.
517 * Arguments: q - queue to operate on
518 * cmd - command that may need to be requeued.
522 * Notes: After command completion, there may be blocks left
523 * over which weren't finished by the previous command
524 * this can be for a number of reasons - the main one is
525 * I/O errors in the middle of the request, in which case
526 * we need to request the blocks that come after the bad
528 * Notes: Upon return, cmd is a stale pointer.
530 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
532 struct scsi_device
*sdev
= cmd
->device
;
533 struct request
*req
= cmd
->request
;
536 spin_lock_irqsave(q
->queue_lock
, flags
);
537 blk_unprep_request(req
);
539 scsi_put_command(cmd
);
540 blk_requeue_request(q
, req
);
541 spin_unlock_irqrestore(q
->queue_lock
, flags
);
545 put_device(&sdev
->sdev_gendev
);
548 void scsi_run_host_queues(struct Scsi_Host
*shost
)
550 struct scsi_device
*sdev
;
552 shost_for_each_device(sdev
, shost
)
553 scsi_run_queue(sdev
->request_queue
);
556 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
560 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
565 index
= get_count_order(nents
) - 3;
570 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
572 struct scsi_host_sg_pool
*sgp
;
574 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
575 mempool_free(sgl
, sgp
->pool
);
578 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
580 struct scsi_host_sg_pool
*sgp
;
582 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
583 return mempool_alloc(sgp
->pool
, gfp_mask
);
586 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
, bool mq
)
588 if (mq
&& sdb
->table
.orig_nents
<= SCSI_MAX_SG_SEGMENTS
)
590 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, mq
, scsi_sg_free
);
593 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
, bool mq
)
595 struct scatterlist
*first_chunk
= NULL
;
601 if (nents
<= SCSI_MAX_SG_SEGMENTS
) {
602 sdb
->table
.nents
= sdb
->table
.orig_nents
= nents
;
603 sg_init_table(sdb
->table
.sgl
, nents
);
606 first_chunk
= sdb
->table
.sgl
;
609 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
610 first_chunk
, GFP_ATOMIC
, scsi_sg_alloc
);
612 scsi_free_sgtable(sdb
, mq
);
616 static void scsi_uninit_cmd(struct scsi_cmnd
*cmd
)
618 if (cmd
->request
->cmd_type
== REQ_TYPE_FS
) {
619 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
621 if (drv
->uninit_command
)
622 drv
->uninit_command(cmd
);
626 static void scsi_mq_free_sgtables(struct scsi_cmnd
*cmd
)
628 if (cmd
->sdb
.table
.nents
)
629 scsi_free_sgtable(&cmd
->sdb
, true);
630 if (cmd
->request
->next_rq
&& cmd
->request
->next_rq
->special
)
631 scsi_free_sgtable(cmd
->request
->next_rq
->special
, true);
632 if (scsi_prot_sg_count(cmd
))
633 scsi_free_sgtable(cmd
->prot_sdb
, true);
636 static void scsi_mq_uninit_cmd(struct scsi_cmnd
*cmd
)
638 struct scsi_device
*sdev
= cmd
->device
;
639 struct Scsi_Host
*shost
= sdev
->host
;
642 scsi_mq_free_sgtables(cmd
);
643 scsi_uninit_cmd(cmd
);
645 if (shost
->use_cmd_list
) {
646 BUG_ON(list_empty(&cmd
->list
));
647 spin_lock_irqsave(&sdev
->list_lock
, flags
);
648 list_del_init(&cmd
->list
);
649 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
654 * Function: scsi_release_buffers()
656 * Purpose: Free resources allocate for a scsi_command.
658 * Arguments: cmd - command that we are bailing.
660 * Lock status: Assumed that no lock is held upon entry.
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
667 * the scatter-gather table.
669 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
671 if (cmd
->sdb
.table
.nents
)
672 scsi_free_sgtable(&cmd
->sdb
, false);
674 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
676 if (scsi_prot_sg_count(cmd
))
677 scsi_free_sgtable(cmd
->prot_sdb
, false);
680 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
682 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
684 scsi_free_sgtable(bidi_sdb
, false);
685 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
686 cmd
->request
->next_rq
->special
= NULL
;
689 static bool scsi_end_request(struct request
*req
, int error
,
690 unsigned int bytes
, unsigned int bidi_bytes
)
692 struct scsi_cmnd
*cmd
= req
->special
;
693 struct scsi_device
*sdev
= cmd
->device
;
694 struct request_queue
*q
= sdev
->request_queue
;
696 if (blk_update_request(req
, error
, bytes
))
699 /* Bidi request must be completed as a whole */
700 if (unlikely(bidi_bytes
) &&
701 blk_update_request(req
->next_rq
, error
, bidi_bytes
))
704 if (blk_queue_add_random(q
))
705 add_disk_randomness(req
->rq_disk
);
709 * In the MQ case the command gets freed by __blk_mq_end_request,
710 * so we have to do all cleanup that depends on it earlier.
712 * We also can't kick the queues from irq context, so we
713 * will have to defer it to a workqueue.
715 scsi_mq_uninit_cmd(cmd
);
717 __blk_mq_end_request(req
, error
);
719 if (scsi_target(sdev
)->single_lun
||
720 !list_empty(&sdev
->host
->starved_list
))
721 kblockd_schedule_work(&sdev
->requeue_work
);
723 blk_mq_start_stopped_hw_queues(q
, true);
728 scsi_release_bidi_buffers(cmd
);
730 spin_lock_irqsave(q
->queue_lock
, flags
);
731 blk_finish_request(req
, error
);
732 spin_unlock_irqrestore(q
->queue_lock
, flags
);
734 scsi_release_buffers(cmd
);
736 scsi_put_command(cmd
);
740 put_device(&sdev
->sdev_gendev
);
745 * __scsi_error_from_host_byte - translate SCSI error code into errno
746 * @cmd: SCSI command (unused)
747 * @result: scsi error code
749 * Translate SCSI error code into standard UNIX errno.
751 * -ENOLINK temporary transport failure
752 * -EREMOTEIO permanent target failure, do not retry
753 * -EBADE permanent nexus failure, retry on other path
754 * -ENOSPC No write space available
755 * -ENODATA Medium error
756 * -EIO unspecified I/O error
758 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
762 switch(host_byte(result
)) {
763 case DID_TRANSPORT_FAILFAST
:
766 case DID_TARGET_FAILURE
:
767 set_host_byte(cmd
, DID_OK
);
770 case DID_NEXUS_FAILURE
:
771 set_host_byte(cmd
, DID_OK
);
774 case DID_ALLOC_FAILURE
:
775 set_host_byte(cmd
, DID_OK
);
778 case DID_MEDIUM_ERROR
:
779 set_host_byte(cmd
, DID_OK
);
791 * Function: scsi_io_completion()
793 * Purpose: Completion processing for block device I/O requests.
795 * Arguments: cmd - command that is finished.
797 * Lock status: Assumed that no lock is held upon entry.
801 * Notes: We will finish off the specified number of sectors. If we
802 * are done, the command block will be released and the queue
803 * function will be goosed. If we are not done then we have to
804 * figure out what to do next:
806 * a) We can call scsi_requeue_command(). The request
807 * will be unprepared and put back on the queue. Then
808 * a new command will be created for it. This should
809 * be used if we made forward progress, or if we want
810 * to switch from READ(10) to READ(6) for example.
812 * b) We can call __scsi_queue_insert(). The request will
813 * be put back on the queue and retried using the same
814 * command as before, possibly after a delay.
816 * c) We can call scsi_end_request() with -EIO to fail
817 * the remainder of the request.
819 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
821 int result
= cmd
->result
;
822 struct request_queue
*q
= cmd
->device
->request_queue
;
823 struct request
*req
= cmd
->request
;
825 struct scsi_sense_hdr sshdr
;
826 bool sense_valid
= false;
827 int sense_deferred
= 0, level
= 0;
828 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
829 ACTION_DELAYED_RETRY
} action
;
830 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
833 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
835 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
838 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
840 if (sense_valid
&& req
->sense
) {
842 * SG_IO wants current and deferred errors
844 int len
= 8 + cmd
->sense_buffer
[7];
846 if (len
> SCSI_SENSE_BUFFERSIZE
)
847 len
= SCSI_SENSE_BUFFERSIZE
;
848 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
849 req
->sense_len
= len
;
852 error
= __scsi_error_from_host_byte(cmd
, result
);
855 * __scsi_error_from_host_byte may have reset the host_byte
857 req
->errors
= cmd
->result
;
859 req
->resid_len
= scsi_get_resid(cmd
);
861 if (scsi_bidi_cmnd(cmd
)) {
863 * Bidi commands Must be complete as a whole,
864 * both sides at once.
866 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
867 if (scsi_end_request(req
, 0, blk_rq_bytes(req
),
868 blk_rq_bytes(req
->next_rq
)))
872 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
874 * Certain non BLOCK_PC requests are commands that don't
875 * actually transfer anything (FLUSH), so cannot use
876 * good_bytes != blk_rq_bytes(req) as the signal for an error.
877 * This sets the error explicitly for the problem case.
879 error
= __scsi_error_from_host_byte(cmd
, result
);
882 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
883 BUG_ON(blk_bidi_rq(req
));
886 * Next deal with any sectors which we were able to correctly
889 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO
, cmd
,
890 "%u sectors total, %d bytes done.\n",
891 blk_rq_sectors(req
), good_bytes
));
894 * Recovered errors need reporting, but they're always treated
895 * as success, so fiddle the result code here. For BLOCK_PC
896 * we already took a copy of the original into rq->errors which
897 * is what gets returned to the user
899 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
900 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
901 * print since caller wants ATA registers. Only occurs on
902 * SCSI ATA PASS_THROUGH commands when CK_COND=1
904 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
906 else if (!(req
->cmd_flags
& REQ_QUIET
))
907 scsi_print_sense(cmd
);
909 /* BLOCK_PC may have set error */
914 * If we finished all bytes in the request we are done now.
916 if (!scsi_end_request(req
, error
, good_bytes
, 0))
920 * Kill remainder if no retrys.
922 if (error
&& scsi_noretry_cmd(cmd
)) {
923 if (scsi_end_request(req
, error
, blk_rq_bytes(req
), 0))
929 * If there had been no error, but we have leftover bytes in the
930 * requeues just queue the command up again.
935 error
= __scsi_error_from_host_byte(cmd
, result
);
937 if (host_byte(result
) == DID_RESET
) {
938 /* Third party bus reset or reset for error recovery
939 * reasons. Just retry the command and see what
942 action
= ACTION_RETRY
;
943 } else if (sense_valid
&& !sense_deferred
) {
944 switch (sshdr
.sense_key
) {
946 if (cmd
->device
->removable
) {
947 /* Detected disc change. Set a bit
948 * and quietly refuse further access.
950 cmd
->device
->changed
= 1;
951 action
= ACTION_FAIL
;
953 /* Must have been a power glitch, or a
954 * bus reset. Could not have been a
955 * media change, so we just retry the
956 * command and see what happens.
958 action
= ACTION_RETRY
;
961 case ILLEGAL_REQUEST
:
962 /* If we had an ILLEGAL REQUEST returned, then
963 * we may have performed an unsupported
964 * command. The only thing this should be
965 * would be a ten byte read where only a six
966 * byte read was supported. Also, on a system
967 * where READ CAPACITY failed, we may have
968 * read past the end of the disk.
970 if ((cmd
->device
->use_10_for_rw
&&
971 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
972 (cmd
->cmnd
[0] == READ_10
||
973 cmd
->cmnd
[0] == WRITE_10
)) {
974 /* This will issue a new 6-byte command. */
975 cmd
->device
->use_10_for_rw
= 0;
976 action
= ACTION_REPREP
;
977 } else if (sshdr
.asc
== 0x10) /* DIX */ {
978 action
= ACTION_FAIL
;
980 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
981 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
982 action
= ACTION_FAIL
;
985 action
= ACTION_FAIL
;
987 case ABORTED_COMMAND
:
988 action
= ACTION_FAIL
;
989 if (sshdr
.asc
== 0x10) /* DIF */
993 /* If the device is in the process of becoming
994 * ready, or has a temporary blockage, retry.
996 if (sshdr
.asc
== 0x04) {
997 switch (sshdr
.ascq
) {
998 case 0x01: /* becoming ready */
999 case 0x04: /* format in progress */
1000 case 0x05: /* rebuild in progress */
1001 case 0x06: /* recalculation in progress */
1002 case 0x07: /* operation in progress */
1003 case 0x08: /* Long write in progress */
1004 case 0x09: /* self test in progress */
1005 case 0x14: /* space allocation in progress */
1006 action
= ACTION_DELAYED_RETRY
;
1009 action
= ACTION_FAIL
;
1013 action
= ACTION_FAIL
;
1015 case VOLUME_OVERFLOW
:
1016 /* See SSC3rXX or current. */
1017 action
= ACTION_FAIL
;
1020 action
= ACTION_FAIL
;
1024 action
= ACTION_FAIL
;
1026 if (action
!= ACTION_FAIL
&&
1027 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
))
1028 action
= ACTION_FAIL
;
1032 /* Give up and fail the remainder of the request */
1033 if (!(req
->cmd_flags
& REQ_QUIET
)) {
1034 static DEFINE_RATELIMIT_STATE(_rs
,
1035 DEFAULT_RATELIMIT_INTERVAL
,
1036 DEFAULT_RATELIMIT_BURST
);
1038 if (unlikely(scsi_logging_level
))
1039 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
1040 SCSI_LOG_MLCOMPLETE_BITS
);
1043 * if logging is enabled the failure will be printed
1044 * in scsi_log_completion(), so avoid duplicate messages
1046 if (!level
&& __ratelimit(&_rs
)) {
1047 scsi_print_result(cmd
, NULL
, FAILED
);
1048 if (driver_byte(result
) & DRIVER_SENSE
)
1049 scsi_print_sense(cmd
);
1050 scsi_print_command(cmd
);
1053 if (!scsi_end_request(req
, error
, blk_rq_err_bytes(req
), 0))
1058 /* Unprep the request and put it back at the head of the queue.
1059 * A new command will be prepared and issued.
1062 cmd
->request
->cmd_flags
&= ~REQ_DONTPREP
;
1063 scsi_mq_uninit_cmd(cmd
);
1064 scsi_mq_requeue_cmd(cmd
);
1066 scsi_release_buffers(cmd
);
1067 scsi_requeue_command(q
, cmd
);
1071 /* Retry the same command immediately */
1072 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1074 case ACTION_DELAYED_RETRY
:
1075 /* Retry the same command after a delay */
1076 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1081 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
)
1086 * If sg table allocation fails, requeue request later.
1088 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
1089 req
->mq_ctx
!= NULL
)))
1090 return BLKPREP_DEFER
;
1093 * Next, walk the list, and fill in the addresses and sizes of
1096 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1097 BUG_ON(count
> sdb
->table
.nents
);
1098 sdb
->table
.nents
= count
;
1099 sdb
->length
= blk_rq_bytes(req
);
1104 * Function: scsi_init_io()
1106 * Purpose: SCSI I/O initialize function.
1108 * Arguments: cmd - Command descriptor we wish to initialize
1110 * Returns: 0 on success
1111 * BLKPREP_DEFER if the failure is retryable
1112 * BLKPREP_KILL if the failure is fatal
1114 int scsi_init_io(struct scsi_cmnd
*cmd
)
1116 struct scsi_device
*sdev
= cmd
->device
;
1117 struct request
*rq
= cmd
->request
;
1118 bool is_mq
= (rq
->mq_ctx
!= NULL
);
1121 BUG_ON(!rq
->nr_phys_segments
);
1123 error
= scsi_init_sgtable(rq
, &cmd
->sdb
);
1127 if (blk_bidi_rq(rq
)) {
1128 if (!rq
->q
->mq_ops
) {
1129 struct scsi_data_buffer
*bidi_sdb
=
1130 kmem_cache_zalloc(scsi_sdb_cache
, GFP_ATOMIC
);
1132 error
= BLKPREP_DEFER
;
1136 rq
->next_rq
->special
= bidi_sdb
;
1139 error
= scsi_init_sgtable(rq
->next_rq
, rq
->next_rq
->special
);
1144 if (blk_integrity_rq(rq
)) {
1145 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1148 if (prot_sdb
== NULL
) {
1150 * This can happen if someone (e.g. multipath)
1151 * queues a command to a device on an adapter
1152 * that does not support DIX.
1155 error
= BLKPREP_KILL
;
1159 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1161 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, is_mq
)) {
1162 error
= BLKPREP_DEFER
;
1166 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1167 prot_sdb
->table
.sgl
);
1168 BUG_ON(unlikely(count
> ivecs
));
1169 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1171 cmd
->prot_sdb
= prot_sdb
;
1172 cmd
->prot_sdb
->table
.nents
= count
;
1178 scsi_mq_free_sgtables(cmd
);
1180 scsi_release_buffers(cmd
);
1181 cmd
->request
->special
= NULL
;
1182 scsi_put_command(cmd
);
1183 put_device(&sdev
->sdev_gendev
);
1187 EXPORT_SYMBOL(scsi_init_io
);
1189 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1190 struct request
*req
)
1192 struct scsi_cmnd
*cmd
;
1194 if (!req
->special
) {
1195 /* Bail if we can't get a reference to the device */
1196 if (!get_device(&sdev
->sdev_gendev
))
1199 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1200 if (unlikely(!cmd
)) {
1201 put_device(&sdev
->sdev_gendev
);
1209 /* pull a tag out of the request if we have one */
1210 cmd
->tag
= req
->tag
;
1213 cmd
->cmnd
= req
->cmd
;
1214 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1219 static int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1221 struct scsi_cmnd
*cmd
= req
->special
;
1224 * BLOCK_PC requests may transfer data, in which case they must
1225 * a bio attached to them. Or they might contain a SCSI command
1226 * that does not transfer data, in which case they may optionally
1227 * submit a request without an attached bio.
1230 int ret
= scsi_init_io(cmd
);
1234 BUG_ON(blk_rq_bytes(req
));
1236 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1239 cmd
->cmd_len
= req
->cmd_len
;
1240 cmd
->transfersize
= blk_rq_bytes(req
);
1241 cmd
->allowed
= req
->retries
;
1246 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1247 * that still need to be translated to SCSI CDBs from the ULD.
1249 static int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1251 struct scsi_cmnd
*cmd
= req
->special
;
1253 if (unlikely(sdev
->handler
&& sdev
->handler
->prep_fn
)) {
1254 int ret
= sdev
->handler
->prep_fn(sdev
, req
);
1255 if (ret
!= BLKPREP_OK
)
1259 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1260 return scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1263 static int scsi_setup_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1265 struct scsi_cmnd
*cmd
= req
->special
;
1267 if (!blk_rq_bytes(req
))
1268 cmd
->sc_data_direction
= DMA_NONE
;
1269 else if (rq_data_dir(req
) == WRITE
)
1270 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1272 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1274 switch (req
->cmd_type
) {
1276 return scsi_setup_fs_cmnd(sdev
, req
);
1277 case REQ_TYPE_BLOCK_PC
:
1278 return scsi_setup_blk_pc_cmnd(sdev
, req
);
1280 return BLKPREP_KILL
;
1285 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1287 int ret
= BLKPREP_OK
;
1290 * If the device is not in running state we will reject some
1293 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1294 switch (sdev
->sdev_state
) {
1296 case SDEV_TRANSPORT_OFFLINE
:
1298 * If the device is offline we refuse to process any
1299 * commands. The device must be brought online
1300 * before trying any recovery commands.
1302 sdev_printk(KERN_ERR
, sdev
,
1303 "rejecting I/O to offline device\n");
1308 * If the device is fully deleted, we refuse to
1309 * process any commands as well.
1311 sdev_printk(KERN_ERR
, sdev
,
1312 "rejecting I/O to dead device\n");
1316 case SDEV_CREATED_BLOCK
:
1317 ret
= BLKPREP_DEFER
;
1321 * If the devices is blocked we defer normal commands.
1323 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1324 ret
= BLKPREP_DEFER
;
1328 * For any other not fully online state we only allow
1329 * special commands. In particular any user initiated
1330 * command is not allowed.
1332 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1341 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1343 struct scsi_device
*sdev
= q
->queuedata
;
1347 req
->errors
= DID_NO_CONNECT
<< 16;
1348 /* release the command and kill it */
1350 struct scsi_cmnd
*cmd
= req
->special
;
1351 scsi_release_buffers(cmd
);
1352 scsi_put_command(cmd
);
1353 put_device(&sdev
->sdev_gendev
);
1354 req
->special
= NULL
;
1359 * If we defer, the blk_peek_request() returns NULL, but the
1360 * queue must be restarted, so we schedule a callback to happen
1363 if (atomic_read(&sdev
->device_busy
) == 0)
1364 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1367 req
->cmd_flags
|= REQ_DONTPREP
;
1373 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1375 struct scsi_device
*sdev
= q
->queuedata
;
1376 struct scsi_cmnd
*cmd
;
1379 ret
= scsi_prep_state_check(sdev
, req
);
1380 if (ret
!= BLKPREP_OK
)
1383 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1384 if (unlikely(!cmd
)) {
1385 ret
= BLKPREP_DEFER
;
1389 ret
= scsi_setup_cmnd(sdev
, req
);
1391 return scsi_prep_return(q
, req
, ret
);
1394 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1396 scsi_uninit_cmd(req
->special
);
1400 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1403 * Called with the queue_lock held.
1405 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1406 struct scsi_device
*sdev
)
1410 busy
= atomic_inc_return(&sdev
->device_busy
) - 1;
1411 if (atomic_read(&sdev
->device_blocked
)) {
1416 * unblock after device_blocked iterates to zero
1418 if (atomic_dec_return(&sdev
->device_blocked
) > 0) {
1420 * For the MQ case we take care of this in the caller.
1423 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1426 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO
, sdev
,
1427 "unblocking device at zero depth\n"));
1430 if (busy
>= sdev
->queue_depth
)
1435 atomic_dec(&sdev
->device_busy
);
1440 * scsi_target_queue_ready: checks if there we can send commands to target
1441 * @sdev: scsi device on starget to check.
1443 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1444 struct scsi_device
*sdev
)
1446 struct scsi_target
*starget
= scsi_target(sdev
);
1449 if (starget
->single_lun
) {
1450 spin_lock_irq(shost
->host_lock
);
1451 if (starget
->starget_sdev_user
&&
1452 starget
->starget_sdev_user
!= sdev
) {
1453 spin_unlock_irq(shost
->host_lock
);
1456 starget
->starget_sdev_user
= sdev
;
1457 spin_unlock_irq(shost
->host_lock
);
1460 if (starget
->can_queue
<= 0)
1463 busy
= atomic_inc_return(&starget
->target_busy
) - 1;
1464 if (atomic_read(&starget
->target_blocked
) > 0) {
1469 * unblock after target_blocked iterates to zero
1471 if (atomic_dec_return(&starget
->target_blocked
) > 0)
1474 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1475 "unblocking target at zero depth\n"));
1478 if (busy
>= starget
->can_queue
)
1484 spin_lock_irq(shost
->host_lock
);
1485 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1486 spin_unlock_irq(shost
->host_lock
);
1488 if (starget
->can_queue
> 0)
1489 atomic_dec(&starget
->target_busy
);
1494 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1495 * return 0. We must end up running the queue again whenever 0 is
1496 * returned, else IO can hang.
1498 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1499 struct Scsi_Host
*shost
,
1500 struct scsi_device
*sdev
)
1504 if (scsi_host_in_recovery(shost
))
1507 busy
= atomic_inc_return(&shost
->host_busy
) - 1;
1508 if (atomic_read(&shost
->host_blocked
) > 0) {
1513 * unblock after host_blocked iterates to zero
1515 if (atomic_dec_return(&shost
->host_blocked
) > 0)
1519 shost_printk(KERN_INFO
, shost
,
1520 "unblocking host at zero depth\n"));
1523 if (shost
->can_queue
> 0 && busy
>= shost
->can_queue
)
1525 if (shost
->host_self_blocked
)
1528 /* We're OK to process the command, so we can't be starved */
1529 if (!list_empty(&sdev
->starved_entry
)) {
1530 spin_lock_irq(shost
->host_lock
);
1531 if (!list_empty(&sdev
->starved_entry
))
1532 list_del_init(&sdev
->starved_entry
);
1533 spin_unlock_irq(shost
->host_lock
);
1539 spin_lock_irq(shost
->host_lock
);
1540 if (list_empty(&sdev
->starved_entry
))
1541 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1542 spin_unlock_irq(shost
->host_lock
);
1544 atomic_dec(&shost
->host_busy
);
1549 * Busy state exporting function for request stacking drivers.
1551 * For efficiency, no lock is taken to check the busy state of
1552 * shost/starget/sdev, since the returned value is not guaranteed and
1553 * may be changed after request stacking drivers call the function,
1554 * regardless of taking lock or not.
1556 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1557 * needs to return 'not busy'. Otherwise, request stacking drivers
1558 * may hold requests forever.
1560 static int scsi_lld_busy(struct request_queue
*q
)
1562 struct scsi_device
*sdev
= q
->queuedata
;
1563 struct Scsi_Host
*shost
;
1565 if (blk_queue_dying(q
))
1571 * Ignore host/starget busy state.
1572 * Since block layer does not have a concept of fairness across
1573 * multiple queues, congestion of host/starget needs to be handled
1576 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1583 * Kill a request for a dead device
1585 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1587 struct scsi_cmnd
*cmd
= req
->special
;
1588 struct scsi_device
*sdev
;
1589 struct scsi_target
*starget
;
1590 struct Scsi_Host
*shost
;
1592 blk_start_request(req
);
1594 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1597 starget
= scsi_target(sdev
);
1599 scsi_init_cmd_errh(cmd
);
1600 cmd
->result
= DID_NO_CONNECT
<< 16;
1601 atomic_inc(&cmd
->device
->iorequest_cnt
);
1604 * SCSI request completion path will do scsi_device_unbusy(),
1605 * bump busy counts. To bump the counters, we need to dance
1606 * with the locks as normal issue path does.
1608 atomic_inc(&sdev
->device_busy
);
1609 atomic_inc(&shost
->host_busy
);
1610 if (starget
->can_queue
> 0)
1611 atomic_inc(&starget
->target_busy
);
1613 blk_complete_request(req
);
1616 static void scsi_softirq_done(struct request
*rq
)
1618 struct scsi_cmnd
*cmd
= rq
->special
;
1619 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1622 INIT_LIST_HEAD(&cmd
->eh_entry
);
1624 atomic_inc(&cmd
->device
->iodone_cnt
);
1626 atomic_inc(&cmd
->device
->ioerr_cnt
);
1628 disposition
= scsi_decide_disposition(cmd
);
1629 if (disposition
!= SUCCESS
&&
1630 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1631 sdev_printk(KERN_ERR
, cmd
->device
,
1632 "timing out command, waited %lus\n",
1634 disposition
= SUCCESS
;
1637 scsi_log_completion(cmd
, disposition
);
1639 switch (disposition
) {
1641 scsi_finish_command(cmd
);
1644 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1646 case ADD_TO_MLQUEUE
:
1647 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1650 if (!scsi_eh_scmd_add(cmd
, 0))
1651 scsi_finish_command(cmd
);
1656 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1657 * @cmd: command block we are dispatching.
1659 * Return: nonzero return request was rejected and device's queue needs to be
1662 static int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
1664 struct Scsi_Host
*host
= cmd
->device
->host
;
1667 atomic_inc(&cmd
->device
->iorequest_cnt
);
1669 /* check if the device is still usable */
1670 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
1671 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1672 * returns an immediate error upwards, and signals
1673 * that the device is no longer present */
1674 cmd
->result
= DID_NO_CONNECT
<< 16;
1678 /* Check to see if the scsi lld made this device blocked. */
1679 if (unlikely(scsi_device_blocked(cmd
->device
))) {
1681 * in blocked state, the command is just put back on
1682 * the device queue. The suspend state has already
1683 * blocked the queue so future requests should not
1684 * occur until the device transitions out of the
1687 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1688 "queuecommand : device blocked\n"));
1689 return SCSI_MLQUEUE_DEVICE_BUSY
;
1692 /* Store the LUN value in cmnd, if needed. */
1693 if (cmd
->device
->lun_in_cdb
)
1694 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
1695 (cmd
->device
->lun
<< 5 & 0xe0);
1700 * Before we queue this command, check if the command
1701 * length exceeds what the host adapter can handle.
1703 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
1704 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1705 "queuecommand : command too long. "
1706 "cdb_size=%d host->max_cmd_len=%d\n",
1707 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
1708 cmd
->result
= (DID_ABORT
<< 16);
1712 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
1713 cmd
->result
= (DID_NO_CONNECT
<< 16);
1718 trace_scsi_dispatch_cmd_start(cmd
);
1719 rtn
= host
->hostt
->queuecommand(host
, cmd
);
1721 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
1722 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
1723 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
1724 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
1726 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO
, cmd
,
1727 "queuecommand : request rejected\n"));
1732 cmd
->scsi_done(cmd
);
1737 * scsi_done - Invoke completion on finished SCSI command.
1738 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1739 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1741 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1742 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1743 * calls blk_complete_request() for further processing.
1745 * This function is interrupt context safe.
1747 static void scsi_done(struct scsi_cmnd
*cmd
)
1749 trace_scsi_dispatch_cmd_done(cmd
);
1750 blk_complete_request(cmd
->request
);
1754 * Function: scsi_request_fn()
1756 * Purpose: Main strategy routine for SCSI.
1758 * Arguments: q - Pointer to actual queue.
1762 * Lock status: IO request lock assumed to be held when called.
1764 static void scsi_request_fn(struct request_queue
*q
)
1765 __releases(q
->queue_lock
)
1766 __acquires(q
->queue_lock
)
1768 struct scsi_device
*sdev
= q
->queuedata
;
1769 struct Scsi_Host
*shost
;
1770 struct scsi_cmnd
*cmd
;
1771 struct request
*req
;
1774 * To start with, we keep looping until the queue is empty, or until
1775 * the host is no longer able to accept any more requests.
1781 * get next queueable request. We do this early to make sure
1782 * that the request is fully prepared even if we cannot
1785 req
= blk_peek_request(q
);
1789 if (unlikely(!scsi_device_online(sdev
))) {
1790 sdev_printk(KERN_ERR
, sdev
,
1791 "rejecting I/O to offline device\n");
1792 scsi_kill_request(req
, q
);
1796 if (!scsi_dev_queue_ready(q
, sdev
))
1800 * Remove the request from the request list.
1802 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1803 blk_start_request(req
);
1805 spin_unlock_irq(q
->queue_lock
);
1807 if (unlikely(cmd
== NULL
)) {
1808 printk(KERN_CRIT
"impossible request in %s.\n"
1809 "please mail a stack trace to "
1810 "linux-scsi@vger.kernel.org\n",
1812 blk_dump_rq_flags(req
, "foo");
1817 * We hit this when the driver is using a host wide
1818 * tag map. For device level tag maps the queue_depth check
1819 * in the device ready fn would prevent us from trying
1820 * to allocate a tag. Since the map is a shared host resource
1821 * we add the dev to the starved list so it eventually gets
1822 * a run when a tag is freed.
1824 if (blk_queue_tagged(q
) && !(req
->cmd_flags
& REQ_QUEUED
)) {
1825 spin_lock_irq(shost
->host_lock
);
1826 if (list_empty(&sdev
->starved_entry
))
1827 list_add_tail(&sdev
->starved_entry
,
1828 &shost
->starved_list
);
1829 spin_unlock_irq(shost
->host_lock
);
1833 if (!scsi_target_queue_ready(shost
, sdev
))
1836 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1837 goto host_not_ready
;
1839 if (sdev
->simple_tags
)
1840 cmd
->flags
|= SCMD_TAGGED
;
1842 cmd
->flags
&= ~SCMD_TAGGED
;
1845 * Finally, initialize any error handling parameters, and set up
1846 * the timers for timeouts.
1848 scsi_init_cmd_errh(cmd
);
1851 * Dispatch the command to the low-level driver.
1853 cmd
->scsi_done
= scsi_done
;
1854 rtn
= scsi_dispatch_cmd(cmd
);
1856 scsi_queue_insert(cmd
, rtn
);
1857 spin_lock_irq(q
->queue_lock
);
1860 spin_lock_irq(q
->queue_lock
);
1866 if (scsi_target(sdev
)->can_queue
> 0)
1867 atomic_dec(&scsi_target(sdev
)->target_busy
);
1870 * lock q, handle tag, requeue req, and decrement device_busy. We
1871 * must return with queue_lock held.
1873 * Decrementing device_busy without checking it is OK, as all such
1874 * cases (host limits or settings) should run the queue at some
1877 spin_lock_irq(q
->queue_lock
);
1878 blk_requeue_request(q
, req
);
1879 atomic_dec(&sdev
->device_busy
);
1881 if (!atomic_read(&sdev
->device_busy
) && !scsi_device_blocked(sdev
))
1882 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1885 static inline int prep_to_mq(int ret
)
1891 return BLK_MQ_RQ_QUEUE_BUSY
;
1893 return BLK_MQ_RQ_QUEUE_ERROR
;
1897 static int scsi_mq_prep_fn(struct request
*req
)
1899 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1900 struct scsi_device
*sdev
= req
->q
->queuedata
;
1901 struct Scsi_Host
*shost
= sdev
->host
;
1902 unsigned char *sense_buf
= cmd
->sense_buffer
;
1903 struct scatterlist
*sg
;
1905 memset(cmd
, 0, sizeof(struct scsi_cmnd
));
1911 cmd
->sense_buffer
= sense_buf
;
1913 cmd
->tag
= req
->tag
;
1915 cmd
->cmnd
= req
->cmd
;
1916 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1918 INIT_LIST_HEAD(&cmd
->list
);
1919 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
1920 cmd
->jiffies_at_alloc
= jiffies
;
1922 if (shost
->use_cmd_list
) {
1923 spin_lock_irq(&sdev
->list_lock
);
1924 list_add_tail(&cmd
->list
, &sdev
->cmd_list
);
1925 spin_unlock_irq(&sdev
->list_lock
);
1928 sg
= (void *)cmd
+ sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
;
1929 cmd
->sdb
.table
.sgl
= sg
;
1931 if (scsi_host_get_prot(shost
)) {
1932 cmd
->prot_sdb
= (void *)sg
+
1934 shost
->sg_tablesize
, SCSI_MAX_SG_SEGMENTS
) *
1935 sizeof(struct scatterlist
);
1936 memset(cmd
->prot_sdb
, 0, sizeof(struct scsi_data_buffer
));
1938 cmd
->prot_sdb
->table
.sgl
=
1939 (struct scatterlist
*)(cmd
->prot_sdb
+ 1);
1942 if (blk_bidi_rq(req
)) {
1943 struct request
*next_rq
= req
->next_rq
;
1944 struct scsi_data_buffer
*bidi_sdb
= blk_mq_rq_to_pdu(next_rq
);
1946 memset(bidi_sdb
, 0, sizeof(struct scsi_data_buffer
));
1947 bidi_sdb
->table
.sgl
=
1948 (struct scatterlist
*)(bidi_sdb
+ 1);
1950 next_rq
->special
= bidi_sdb
;
1953 blk_mq_start_request(req
);
1955 return scsi_setup_cmnd(sdev
, req
);
1958 static void scsi_mq_done(struct scsi_cmnd
*cmd
)
1960 trace_scsi_dispatch_cmd_done(cmd
);
1961 blk_mq_complete_request(cmd
->request
, cmd
->request
->errors
);
1964 static int scsi_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1965 const struct blk_mq_queue_data
*bd
)
1967 struct request
*req
= bd
->rq
;
1968 struct request_queue
*q
= req
->q
;
1969 struct scsi_device
*sdev
= q
->queuedata
;
1970 struct Scsi_Host
*shost
= sdev
->host
;
1971 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(req
);
1975 ret
= prep_to_mq(scsi_prep_state_check(sdev
, req
));
1979 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
1980 if (!get_device(&sdev
->sdev_gendev
))
1983 if (!scsi_dev_queue_ready(q
, sdev
))
1984 goto out_put_device
;
1985 if (!scsi_target_queue_ready(shost
, sdev
))
1986 goto out_dec_device_busy
;
1987 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1988 goto out_dec_target_busy
;
1991 if (!(req
->cmd_flags
& REQ_DONTPREP
)) {
1992 ret
= prep_to_mq(scsi_mq_prep_fn(req
));
1994 goto out_dec_host_busy
;
1995 req
->cmd_flags
|= REQ_DONTPREP
;
1997 blk_mq_start_request(req
);
2000 if (sdev
->simple_tags
)
2001 cmd
->flags
|= SCMD_TAGGED
;
2003 cmd
->flags
&= ~SCMD_TAGGED
;
2005 scsi_init_cmd_errh(cmd
);
2006 cmd
->scsi_done
= scsi_mq_done
;
2008 reason
= scsi_dispatch_cmd(cmd
);
2010 scsi_set_blocked(cmd
, reason
);
2011 ret
= BLK_MQ_RQ_QUEUE_BUSY
;
2012 goto out_dec_host_busy
;
2015 return BLK_MQ_RQ_QUEUE_OK
;
2018 atomic_dec(&shost
->host_busy
);
2019 out_dec_target_busy
:
2020 if (scsi_target(sdev
)->can_queue
> 0)
2021 atomic_dec(&scsi_target(sdev
)->target_busy
);
2022 out_dec_device_busy
:
2023 atomic_dec(&sdev
->device_busy
);
2025 put_device(&sdev
->sdev_gendev
);
2028 case BLK_MQ_RQ_QUEUE_BUSY
:
2029 blk_mq_stop_hw_queue(hctx
);
2030 if (atomic_read(&sdev
->device_busy
) == 0 &&
2031 !scsi_device_blocked(sdev
))
2032 blk_mq_delay_queue(hctx
, SCSI_QUEUE_DELAY
);
2034 case BLK_MQ_RQ_QUEUE_ERROR
:
2036 * Make sure to release all allocated ressources when
2037 * we hit an error, as we will never see this command
2040 if (req
->cmd_flags
& REQ_DONTPREP
)
2041 scsi_mq_uninit_cmd(cmd
);
2049 static enum blk_eh_timer_return
scsi_timeout(struct request
*req
,
2053 return BLK_EH_RESET_TIMER
;
2054 return scsi_times_out(req
);
2057 static int scsi_init_request(void *data
, struct request
*rq
,
2058 unsigned int hctx_idx
, unsigned int request_idx
,
2059 unsigned int numa_node
)
2061 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2063 cmd
->sense_buffer
= kzalloc_node(SCSI_SENSE_BUFFERSIZE
, GFP_KERNEL
,
2065 if (!cmd
->sense_buffer
)
2070 static void scsi_exit_request(void *data
, struct request
*rq
,
2071 unsigned int hctx_idx
, unsigned int request_idx
)
2073 struct scsi_cmnd
*cmd
= blk_mq_rq_to_pdu(rq
);
2075 kfree(cmd
->sense_buffer
);
2078 static u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
2080 struct device
*host_dev
;
2081 u64 bounce_limit
= 0xffffffff;
2083 if (shost
->unchecked_isa_dma
)
2084 return BLK_BOUNCE_ISA
;
2086 * Platforms with virtual-DMA translation
2087 * hardware have no practical limit.
2089 if (!PCI_DMA_BUS_IS_PHYS
)
2090 return BLK_BOUNCE_ANY
;
2092 host_dev
= scsi_get_device(shost
);
2093 if (host_dev
&& host_dev
->dma_mask
)
2094 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
2096 return bounce_limit
;
2099 static void __scsi_init_queue(struct Scsi_Host
*shost
, struct request_queue
*q
)
2101 struct device
*dev
= shost
->dma_dev
;
2104 * this limit is imposed by hardware restrictions
2106 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
2107 SCSI_MAX_SG_CHAIN_SEGMENTS
));
2109 if (scsi_host_prot_dma(shost
)) {
2110 shost
->sg_prot_tablesize
=
2111 min_not_zero(shost
->sg_prot_tablesize
,
2112 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
2113 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
2114 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
2117 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
2118 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
2119 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
2120 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
2122 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
2124 if (!shost
->use_clustering
)
2125 q
->limits
.cluster
= 0;
2128 * set a reasonable default alignment on word boundaries: the
2129 * host and device may alter it using
2130 * blk_queue_update_dma_alignment() later.
2132 blk_queue_dma_alignment(q
, 0x03);
2135 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
2136 request_fn_proc
*request_fn
)
2138 struct request_queue
*q
;
2140 q
= blk_init_queue(request_fn
, NULL
);
2143 __scsi_init_queue(shost
, q
);
2146 EXPORT_SYMBOL(__scsi_alloc_queue
);
2148 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
2150 struct request_queue
*q
;
2152 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
2156 blk_queue_prep_rq(q
, scsi_prep_fn
);
2157 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
2158 blk_queue_softirq_done(q
, scsi_softirq_done
);
2159 blk_queue_rq_timed_out(q
, scsi_times_out
);
2160 blk_queue_lld_busy(q
, scsi_lld_busy
);
2164 static struct blk_mq_ops scsi_mq_ops
= {
2165 .map_queue
= blk_mq_map_queue
,
2166 .queue_rq
= scsi_queue_rq
,
2167 .complete
= scsi_softirq_done
,
2168 .timeout
= scsi_timeout
,
2169 .init_request
= scsi_init_request
,
2170 .exit_request
= scsi_exit_request
,
2173 struct request_queue
*scsi_mq_alloc_queue(struct scsi_device
*sdev
)
2175 sdev
->request_queue
= blk_mq_init_queue(&sdev
->host
->tag_set
);
2176 if (IS_ERR(sdev
->request_queue
))
2179 sdev
->request_queue
->queuedata
= sdev
;
2180 __scsi_init_queue(sdev
->host
, sdev
->request_queue
);
2181 return sdev
->request_queue
;
2184 int scsi_mq_setup_tags(struct Scsi_Host
*shost
)
2186 unsigned int cmd_size
, sgl_size
, tbl_size
;
2188 tbl_size
= shost
->sg_tablesize
;
2189 if (tbl_size
> SCSI_MAX_SG_SEGMENTS
)
2190 tbl_size
= SCSI_MAX_SG_SEGMENTS
;
2191 sgl_size
= tbl_size
* sizeof(struct scatterlist
);
2192 cmd_size
= sizeof(struct scsi_cmnd
) + shost
->hostt
->cmd_size
+ sgl_size
;
2193 if (scsi_host_get_prot(shost
))
2194 cmd_size
+= sizeof(struct scsi_data_buffer
) + sgl_size
;
2196 memset(&shost
->tag_set
, 0, sizeof(shost
->tag_set
));
2197 shost
->tag_set
.ops
= &scsi_mq_ops
;
2198 shost
->tag_set
.nr_hw_queues
= shost
->nr_hw_queues
? : 1;
2199 shost
->tag_set
.queue_depth
= shost
->can_queue
;
2200 shost
->tag_set
.cmd_size
= cmd_size
;
2201 shost
->tag_set
.numa_node
= NUMA_NO_NODE
;
2202 shost
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2203 shost
->tag_set
.flags
|=
2204 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost
->hostt
->tag_alloc_policy
);
2205 shost
->tag_set
.driver_data
= shost
;
2207 return blk_mq_alloc_tag_set(&shost
->tag_set
);
2210 void scsi_mq_destroy_tags(struct Scsi_Host
*shost
)
2212 blk_mq_free_tag_set(&shost
->tag_set
);
2216 * Function: scsi_block_requests()
2218 * Purpose: Utility function used by low-level drivers to prevent further
2219 * commands from being queued to the device.
2221 * Arguments: shost - Host in question
2225 * Lock status: No locks are assumed held.
2227 * Notes: There is no timer nor any other means by which the requests
2228 * get unblocked other than the low-level driver calling
2229 * scsi_unblock_requests().
2231 void scsi_block_requests(struct Scsi_Host
*shost
)
2233 shost
->host_self_blocked
= 1;
2235 EXPORT_SYMBOL(scsi_block_requests
);
2238 * Function: scsi_unblock_requests()
2240 * Purpose: Utility function used by low-level drivers to allow further
2241 * commands from being queued to the device.
2243 * Arguments: shost - Host in question
2247 * Lock status: No locks are assumed held.
2249 * Notes: There is no timer nor any other means by which the requests
2250 * get unblocked other than the low-level driver calling
2251 * scsi_unblock_requests().
2253 * This is done as an API function so that changes to the
2254 * internals of the scsi mid-layer won't require wholesale
2255 * changes to drivers that use this feature.
2257 void scsi_unblock_requests(struct Scsi_Host
*shost
)
2259 shost
->host_self_blocked
= 0;
2260 scsi_run_host_queues(shost
);
2262 EXPORT_SYMBOL(scsi_unblock_requests
);
2264 int __init
scsi_init_queue(void)
2268 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
2269 sizeof(struct scsi_data_buffer
),
2271 if (!scsi_sdb_cache
) {
2272 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
2276 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
2277 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
2278 int size
= sgp
->size
* sizeof(struct scatterlist
);
2280 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
2281 SLAB_HWCACHE_ALIGN
, NULL
);
2283 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
2288 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
2291 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
2300 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
2301 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
2303 mempool_destroy(sgp
->pool
);
2305 kmem_cache_destroy(sgp
->slab
);
2307 kmem_cache_destroy(scsi_sdb_cache
);
2312 void scsi_exit_queue(void)
2316 kmem_cache_destroy(scsi_sdb_cache
);
2318 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
2319 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
2320 mempool_destroy(sgp
->pool
);
2321 kmem_cache_destroy(sgp
->slab
);
2326 * scsi_mode_select - issue a mode select
2327 * @sdev: SCSI device to be queried
2328 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2329 * @sp: Save page bit (0 == don't save, 1 == save)
2330 * @modepage: mode page being requested
2331 * @buffer: request buffer (may not be smaller than eight bytes)
2332 * @len: length of request buffer.
2333 * @timeout: command timeout
2334 * @retries: number of retries before failing
2335 * @data: returns a structure abstracting the mode header data
2336 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2337 * must be SCSI_SENSE_BUFFERSIZE big.
2339 * Returns zero if successful; negative error number or scsi
2344 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
2345 unsigned char *buffer
, int len
, int timeout
, int retries
,
2346 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2348 unsigned char cmd
[10];
2349 unsigned char *real_buffer
;
2352 memset(cmd
, 0, sizeof(cmd
));
2353 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
2355 if (sdev
->use_10_for_ms
) {
2358 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
2361 memcpy(real_buffer
+ 8, buffer
, len
);
2365 real_buffer
[2] = data
->medium_type
;
2366 real_buffer
[3] = data
->device_specific
;
2367 real_buffer
[4] = data
->longlba
? 0x01 : 0;
2369 real_buffer
[6] = data
->block_descriptor_length
>> 8;
2370 real_buffer
[7] = data
->block_descriptor_length
;
2372 cmd
[0] = MODE_SELECT_10
;
2376 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2380 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2383 memcpy(real_buffer
+ 4, buffer
, len
);
2386 real_buffer
[1] = data
->medium_type
;
2387 real_buffer
[2] = data
->device_specific
;
2388 real_buffer
[3] = data
->block_descriptor_length
;
2391 cmd
[0] = MODE_SELECT
;
2395 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2396 sshdr
, timeout
, retries
, NULL
);
2400 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2403 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2404 * @sdev: SCSI device to be queried
2405 * @dbd: set if mode sense will allow block descriptors to be returned
2406 * @modepage: mode page being requested
2407 * @buffer: request buffer (may not be smaller than eight bytes)
2408 * @len: length of request buffer.
2409 * @timeout: command timeout
2410 * @retries: number of retries before failing
2411 * @data: returns a structure abstracting the mode header data
2412 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2413 * must be SCSI_SENSE_BUFFERSIZE big.
2415 * Returns zero if unsuccessful, or the header offset (either 4
2416 * or 8 depending on whether a six or ten byte command was
2417 * issued) if successful.
2420 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2421 unsigned char *buffer
, int len
, int timeout
, int retries
,
2422 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2424 unsigned char cmd
[12];
2427 int result
, retry_count
= retries
;
2428 struct scsi_sense_hdr my_sshdr
;
2430 memset(data
, 0, sizeof(*data
));
2431 memset(&cmd
[0], 0, 12);
2432 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2435 /* caller might not be interested in sense, but we need it */
2440 use_10_for_ms
= sdev
->use_10_for_ms
;
2442 if (use_10_for_ms
) {
2446 cmd
[0] = MODE_SENSE_10
;
2453 cmd
[0] = MODE_SENSE
;
2458 memset(buffer
, 0, len
);
2460 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2461 sshdr
, timeout
, retries
, NULL
);
2463 /* This code looks awful: what it's doing is making sure an
2464 * ILLEGAL REQUEST sense return identifies the actual command
2465 * byte as the problem. MODE_SENSE commands can return
2466 * ILLEGAL REQUEST if the code page isn't supported */
2468 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2469 (driver_byte(result
) & DRIVER_SENSE
)) {
2470 if (scsi_sense_valid(sshdr
)) {
2471 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2472 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2474 * Invalid command operation code
2476 sdev
->use_10_for_ms
= 0;
2482 if(scsi_status_is_good(result
)) {
2483 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2484 (modepage
== 6 || modepage
== 8))) {
2485 /* Initio breakage? */
2488 data
->medium_type
= 0;
2489 data
->device_specific
= 0;
2491 data
->block_descriptor_length
= 0;
2492 } else if(use_10_for_ms
) {
2493 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2494 data
->medium_type
= buffer
[2];
2495 data
->device_specific
= buffer
[3];
2496 data
->longlba
= buffer
[4] & 0x01;
2497 data
->block_descriptor_length
= buffer
[6]*256
2500 data
->length
= buffer
[0] + 1;
2501 data
->medium_type
= buffer
[1];
2502 data
->device_specific
= buffer
[2];
2503 data
->block_descriptor_length
= buffer
[3];
2505 data
->header_length
= header_length
;
2506 } else if ((status_byte(result
) == CHECK_CONDITION
) &&
2507 scsi_sense_valid(sshdr
) &&
2508 sshdr
->sense_key
== UNIT_ATTENTION
&& retry_count
) {
2515 EXPORT_SYMBOL(scsi_mode_sense
);
2518 * scsi_test_unit_ready - test if unit is ready
2519 * @sdev: scsi device to change the state of.
2520 * @timeout: command timeout
2521 * @retries: number of retries before failing
2522 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2523 * returning sense. Make sure that this is cleared before passing
2526 * Returns zero if unsuccessful or an error if TUR failed. For
2527 * removable media, UNIT_ATTENTION sets ->changed flag.
2530 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2531 struct scsi_sense_hdr
*sshdr_external
)
2534 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2536 struct scsi_sense_hdr
*sshdr
;
2539 if (!sshdr_external
)
2540 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2542 sshdr
= sshdr_external
;
2544 /* try to eat the UNIT_ATTENTION if there are enough retries */
2546 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2547 timeout
, retries
, NULL
);
2548 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2549 sshdr
->sense_key
== UNIT_ATTENTION
)
2551 } while (scsi_sense_valid(sshdr
) &&
2552 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2554 if (!sshdr_external
)
2558 EXPORT_SYMBOL(scsi_test_unit_ready
);
2561 * scsi_device_set_state - Take the given device through the device state model.
2562 * @sdev: scsi device to change the state of.
2563 * @state: state to change to.
2565 * Returns zero if unsuccessful or an error if the requested
2566 * transition is illegal.
2569 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2571 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2573 if (state
== oldstate
)
2579 case SDEV_CREATED_BLOCK
:
2590 case SDEV_TRANSPORT_OFFLINE
:
2603 case SDEV_TRANSPORT_OFFLINE
:
2611 case SDEV_TRANSPORT_OFFLINE
:
2626 case SDEV_CREATED_BLOCK
:
2633 case SDEV_CREATED_BLOCK
:
2648 case SDEV_TRANSPORT_OFFLINE
:
2661 case SDEV_TRANSPORT_OFFLINE
:
2663 case SDEV_CREATED_BLOCK
:
2671 sdev
->sdev_state
= state
;
2675 SCSI_LOG_ERROR_RECOVERY(1,
2676 sdev_printk(KERN_ERR
, sdev
,
2677 "Illegal state transition %s->%s",
2678 scsi_device_state_name(oldstate
),
2679 scsi_device_state_name(state
))
2683 EXPORT_SYMBOL(scsi_device_set_state
);
2686 * sdev_evt_emit - emit a single SCSI device uevent
2687 * @sdev: associated SCSI device
2688 * @evt: event to emit
2690 * Send a single uevent (scsi_event) to the associated scsi_device.
2692 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2697 switch (evt
->evt_type
) {
2698 case SDEV_EVT_MEDIA_CHANGE
:
2699 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2701 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2702 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2704 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2705 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2707 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2708 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2710 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2711 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2713 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2714 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2716 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2717 envp
[idx
++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2726 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2730 * sdev_evt_thread - send a uevent for each scsi event
2731 * @work: work struct for scsi_device
2733 * Dispatch queued events to their associated scsi_device kobjects
2736 void scsi_evt_thread(struct work_struct
*work
)
2738 struct scsi_device
*sdev
;
2739 enum scsi_device_event evt_type
;
2740 LIST_HEAD(event_list
);
2742 sdev
= container_of(work
, struct scsi_device
, event_work
);
2744 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2745 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2746 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2749 struct scsi_event
*evt
;
2750 struct list_head
*this, *tmp
;
2751 unsigned long flags
;
2753 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2754 list_splice_init(&sdev
->event_list
, &event_list
);
2755 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2757 if (list_empty(&event_list
))
2760 list_for_each_safe(this, tmp
, &event_list
) {
2761 evt
= list_entry(this, struct scsi_event
, node
);
2762 list_del(&evt
->node
);
2763 scsi_evt_emit(sdev
, evt
);
2770 * sdev_evt_send - send asserted event to uevent thread
2771 * @sdev: scsi_device event occurred on
2772 * @evt: event to send
2774 * Assert scsi device event asynchronously.
2776 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2778 unsigned long flags
;
2781 /* FIXME: currently this check eliminates all media change events
2782 * for polled devices. Need to update to discriminate between AN
2783 * and polled events */
2784 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2790 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2791 list_add_tail(&evt
->node
, &sdev
->event_list
);
2792 schedule_work(&sdev
->event_work
);
2793 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2795 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2798 * sdev_evt_alloc - allocate a new scsi event
2799 * @evt_type: type of event to allocate
2800 * @gfpflags: GFP flags for allocation
2802 * Allocates and returns a new scsi_event.
2804 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2807 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2811 evt
->evt_type
= evt_type
;
2812 INIT_LIST_HEAD(&evt
->node
);
2814 /* evt_type-specific initialization, if any */
2816 case SDEV_EVT_MEDIA_CHANGE
:
2817 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2818 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2819 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2820 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2821 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2822 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED
:
2830 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2833 * sdev_evt_send_simple - send asserted event to uevent thread
2834 * @sdev: scsi_device event occurred on
2835 * @evt_type: type of event to send
2836 * @gfpflags: GFP flags for allocation
2838 * Assert scsi device event asynchronously, given an event type.
2840 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2841 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2843 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2845 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2850 sdev_evt_send(sdev
, evt
);
2852 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2855 * scsi_device_quiesce - Block user issued commands.
2856 * @sdev: scsi device to quiesce.
2858 * This works by trying to transition to the SDEV_QUIESCE state
2859 * (which must be a legal transition). When the device is in this
2860 * state, only special requests will be accepted, all others will
2861 * be deferred. Since special requests may also be requeued requests,
2862 * a successful return doesn't guarantee the device will be
2863 * totally quiescent.
2865 * Must be called with user context, may sleep.
2867 * Returns zero if unsuccessful or an error if not.
2870 scsi_device_quiesce(struct scsi_device
*sdev
)
2872 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2876 scsi_run_queue(sdev
->request_queue
);
2877 while (atomic_read(&sdev
->device_busy
)) {
2878 msleep_interruptible(200);
2879 scsi_run_queue(sdev
->request_queue
);
2883 EXPORT_SYMBOL(scsi_device_quiesce
);
2886 * scsi_device_resume - Restart user issued commands to a quiesced device.
2887 * @sdev: scsi device to resume.
2889 * Moves the device from quiesced back to running and restarts the
2892 * Must be called with user context, may sleep.
2894 void scsi_device_resume(struct scsi_device
*sdev
)
2896 /* check if the device state was mutated prior to resume, and if
2897 * so assume the state is being managed elsewhere (for example
2898 * device deleted during suspend)
2900 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2901 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2903 scsi_run_queue(sdev
->request_queue
);
2905 EXPORT_SYMBOL(scsi_device_resume
);
2908 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2910 scsi_device_quiesce(sdev
);
2914 scsi_target_quiesce(struct scsi_target
*starget
)
2916 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2918 EXPORT_SYMBOL(scsi_target_quiesce
);
2921 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2923 scsi_device_resume(sdev
);
2927 scsi_target_resume(struct scsi_target
*starget
)
2929 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2931 EXPORT_SYMBOL(scsi_target_resume
);
2934 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2935 * @sdev: device to block
2937 * Block request made by scsi lld's to temporarily stop all
2938 * scsi commands on the specified device. Called from interrupt
2939 * or normal process context.
2941 * Returns zero if successful or error if not
2944 * This routine transitions the device to the SDEV_BLOCK state
2945 * (which must be a legal transition). When the device is in this
2946 * state, all commands are deferred until the scsi lld reenables
2947 * the device with scsi_device_unblock or device_block_tmo fires.
2950 scsi_internal_device_block(struct scsi_device
*sdev
)
2952 struct request_queue
*q
= sdev
->request_queue
;
2953 unsigned long flags
;
2956 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2958 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2965 * The device has transitioned to SDEV_BLOCK. Stop the
2966 * block layer from calling the midlayer with this device's
2970 blk_mq_stop_hw_queues(q
);
2972 spin_lock_irqsave(q
->queue_lock
, flags
);
2974 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2979 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2982 * scsi_internal_device_unblock - resume a device after a block request
2983 * @sdev: device to resume
2984 * @new_state: state to set devices to after unblocking
2986 * Called by scsi lld's or the midlayer to restart the device queue
2987 * for the previously suspended scsi device. Called from interrupt or
2988 * normal process context.
2990 * Returns zero if successful or error if not.
2993 * This routine transitions the device to the SDEV_RUNNING state
2994 * or to one of the offline states (which must be a legal transition)
2995 * allowing the midlayer to goose the queue for this device.
2998 scsi_internal_device_unblock(struct scsi_device
*sdev
,
2999 enum scsi_device_state new_state
)
3001 struct request_queue
*q
= sdev
->request_queue
;
3002 unsigned long flags
;
3005 * Try to transition the scsi device to SDEV_RUNNING or one of the
3006 * offlined states and goose the device queue if successful.
3008 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
3009 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
3010 sdev
->sdev_state
= new_state
;
3011 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
3012 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
3013 new_state
== SDEV_OFFLINE
)
3014 sdev
->sdev_state
= new_state
;
3016 sdev
->sdev_state
= SDEV_CREATED
;
3017 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
3018 sdev
->sdev_state
!= SDEV_OFFLINE
)
3022 blk_mq_start_stopped_hw_queues(q
, false);
3024 spin_lock_irqsave(q
->queue_lock
, flags
);
3026 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3031 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
3034 device_block(struct scsi_device
*sdev
, void *data
)
3036 scsi_internal_device_block(sdev
);
3040 target_block(struct device
*dev
, void *data
)
3042 if (scsi_is_target_device(dev
))
3043 starget_for_each_device(to_scsi_target(dev
), NULL
,
3049 scsi_target_block(struct device
*dev
)
3051 if (scsi_is_target_device(dev
))
3052 starget_for_each_device(to_scsi_target(dev
), NULL
,
3055 device_for_each_child(dev
, NULL
, target_block
);
3057 EXPORT_SYMBOL_GPL(scsi_target_block
);
3060 device_unblock(struct scsi_device
*sdev
, void *data
)
3062 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
3066 target_unblock(struct device
*dev
, void *data
)
3068 if (scsi_is_target_device(dev
))
3069 starget_for_each_device(to_scsi_target(dev
), data
,
3075 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
3077 if (scsi_is_target_device(dev
))
3078 starget_for_each_device(to_scsi_target(dev
), &new_state
,
3081 device_for_each_child(dev
, &new_state
, target_unblock
);
3083 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
3086 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3087 * @sgl: scatter-gather list
3088 * @sg_count: number of segments in sg
3089 * @offset: offset in bytes into sg, on return offset into the mapped area
3090 * @len: bytes to map, on return number of bytes mapped
3092 * Returns virtual address of the start of the mapped page
3094 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
3095 size_t *offset
, size_t *len
)
3098 size_t sg_len
= 0, len_complete
= 0;
3099 struct scatterlist
*sg
;
3102 WARN_ON(!irqs_disabled());
3104 for_each_sg(sgl
, sg
, sg_count
, i
) {
3105 len_complete
= sg_len
; /* Complete sg-entries */
3106 sg_len
+= sg
->length
;
3107 if (sg_len
> *offset
)
3111 if (unlikely(i
== sg_count
)) {
3112 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
3114 __func__
, sg_len
, *offset
, sg_count
);
3119 /* Offset starting from the beginning of first page in this sg-entry */
3120 *offset
= *offset
- len_complete
+ sg
->offset
;
3122 /* Assumption: contiguous pages can be accessed as "page + i" */
3123 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
3124 *offset
&= ~PAGE_MASK
;
3126 /* Bytes in this sg-entry from *offset to the end of the page */
3127 sg_len
= PAGE_SIZE
- *offset
;
3131 return kmap_atomic(page
);
3133 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
3136 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3137 * @virt: virtual address to be unmapped
3139 void scsi_kunmap_atomic_sg(void *virt
)
3141 kunmap_atomic(virt
);
3143 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
3145 void sdev_disable_disk_events(struct scsi_device
*sdev
)
3147 atomic_inc(&sdev
->disk_events_disable_depth
);
3149 EXPORT_SYMBOL(sdev_disable_disk_events
);
3151 void sdev_enable_disk_events(struct scsi_device
*sdev
)
3153 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
3155 atomic_dec(&sdev
->disk_events_disable_depth
);
3157 EXPORT_SYMBOL(sdev_enable_disk_events
);
3160 * scsi_vpd_lun_id - return a unique device identification
3161 * @sdev: SCSI device
3162 * @id: buffer for the identification
3163 * @id_len: length of the buffer
3165 * Copies a unique device identification into @id based
3166 * on the information in the VPD page 0x83 of the device.
3167 * The string will be formatted as a SCSI name string.
3169 * Returns the length of the identification or error on failure.
3170 * If the identifier is longer than the supplied buffer the actual
3171 * identifier length is returned and the buffer is not zero-padded.
3173 int scsi_vpd_lun_id(struct scsi_device
*sdev
, char *id
, size_t id_len
)
3175 u8 cur_id_type
= 0xff;
3177 unsigned char *d
, *cur_id_str
;
3178 unsigned char __rcu
*vpd_pg83
;
3179 int id_size
= -EINVAL
;
3182 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3189 * Look for the correct descriptor.
3190 * Order of preference for lun descriptor:
3191 * - SCSI name string
3192 * - NAA IEEE Registered Extended
3193 * - EUI-64 based 16-byte
3194 * - EUI-64 based 12-byte
3195 * - NAA IEEE Registered
3196 * - NAA IEEE Extended
3197 * as longer descriptors reduce the likelyhood
3198 * of identification clashes.
3201 /* The id string must be at least 20 bytes + terminating NULL byte */
3207 memset(id
, 0, id_len
);
3209 while (d
< vpd_pg83
+ sdev
->vpd_pg83_len
) {
3210 /* Skip designators not referring to the LUN */
3211 if ((d
[1] & 0x30) != 0x00)
3214 switch (d
[1] & 0xf) {
3217 if (cur_id_size
> d
[3])
3219 /* Prefer NAA IEEE Registered Extended */
3220 if (cur_id_type
== 0x3 &&
3221 cur_id_size
== d
[3])
3225 cur_id_type
= d
[1] & 0xf;
3226 switch (cur_id_size
) {
3228 id_size
= snprintf(id
, id_len
,
3233 id_size
= snprintf(id
, id_len
,
3238 id_size
= snprintf(id
, id_len
,
3249 if (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
,
3271 /* SCSI name string */
3272 if (cur_id_size
+ 4 > d
[3])
3274 /* Prefer others for truncated descriptor */
3275 if (cur_id_size
&& d
[3] > id_len
)
3277 cur_id_size
= id_size
= d
[3];
3279 cur_id_type
= d
[1] & 0xf;
3280 if (cur_id_size
>= id_len
)
3281 cur_id_size
= id_len
- 1;
3282 memcpy(id
, cur_id_str
, cur_id_size
);
3283 /* Decrease priority for truncated descriptor */
3284 if (cur_id_size
!= id_size
)
3297 EXPORT_SYMBOL(scsi_vpd_lun_id
);
3300 * scsi_vpd_tpg_id - return a target port group identifier
3301 * @sdev: SCSI device
3303 * Returns the Target Port Group identifier from the information
3304 * froom VPD page 0x83 of the device.
3306 * Returns the identifier or error on failure.
3308 int scsi_vpd_tpg_id(struct scsi_device
*sdev
, int *rel_id
)
3311 unsigned char __rcu
*vpd_pg83
;
3312 int group_id
= -EAGAIN
, rel_port
= -1;
3315 vpd_pg83
= rcu_dereference(sdev
->vpd_pg83
);
3321 d
= sdev
->vpd_pg83
+ 4;
3322 while (d
< sdev
->vpd_pg83
+ sdev
->vpd_pg83_len
) {
3323 switch (d
[1] & 0xf) {
3325 /* Relative target port */
3326 rel_port
= get_unaligned_be16(&d
[6]);
3329 /* Target port group */
3330 group_id
= get_unaligned_be16(&d
[6]);
3339 if (group_id
>= 0 && rel_id
&& rel_port
!= -1)
3344 EXPORT_SYMBOL(scsi_vpd_tpg_id
);