2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
10 #include <linux/bio.h>
11 #include <linux/bitops.h>
12 #include <linux/blkdev.h>
13 #include <linux/completion.h>
14 #include <linux/kernel.h>
15 #include <linux/mempool.h>
16 #include <linux/slab.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>
23 #include <scsi/scsi.h>
24 #include <scsi/scsi_cmnd.h>
25 #include <scsi/scsi_dbg.h>
26 #include <scsi/scsi_device.h>
27 #include <scsi/scsi_driver.h>
28 #include <scsi/scsi_eh.h>
29 #include <scsi/scsi_host.h>
31 #include "scsi_priv.h"
32 #include "scsi_logging.h"
35 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
36 #define SG_MEMPOOL_SIZE 2
38 struct scsi_host_sg_pool
{
41 struct kmem_cache
*slab
;
45 #define SP(x) { x, "sgpool-" __stringify(x) }
46 #if (SCSI_MAX_SG_SEGMENTS < 32)
47 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
49 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
52 #if (SCSI_MAX_SG_SEGMENTS > 32)
54 #if (SCSI_MAX_SG_SEGMENTS > 64)
56 #if (SCSI_MAX_SG_SEGMENTS > 128)
58 #if (SCSI_MAX_SG_SEGMENTS > 256)
59 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
64 SP(SCSI_MAX_SG_SEGMENTS
)
68 struct kmem_cache
*scsi_sdb_cache
;
70 static void scsi_run_queue(struct request_queue
*q
);
73 * Function: scsi_unprep_request()
75 * Purpose: Remove all preparation done for a request, including its
76 * associated scsi_cmnd, so that it can be requeued.
78 * Arguments: req - request to unprepare
80 * Lock status: Assumed that no locks are held upon entry.
84 static void scsi_unprep_request(struct request
*req
)
86 struct scsi_cmnd
*cmd
= req
->special
;
88 req
->cmd_flags
&= ~REQ_DONTPREP
;
91 scsi_put_command(cmd
);
95 * Function: scsi_queue_insert()
97 * Purpose: Insert a command in the midlevel queue.
99 * Arguments: cmd - command that we are adding to queue.
100 * reason - why we are inserting command to queue.
102 * Lock status: Assumed that lock is not held upon entry.
106 * Notes: We do this for one of two cases. Either the host is busy
107 * and it cannot accept any more commands for the time being,
108 * or the device returned QUEUE_FULL and can accept no more
110 * Notes: This could be called either from an interrupt context or a
111 * normal process context.
113 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
115 struct Scsi_Host
*host
= cmd
->device
->host
;
116 struct scsi_device
*device
= cmd
->device
;
117 struct scsi_target
*starget
= scsi_target(device
);
118 struct request_queue
*q
= device
->request_queue
;
122 printk("Inserting command %p into mlqueue\n", cmd
));
125 * Set the appropriate busy bit for the device/host.
127 * If the host/device isn't busy, assume that something actually
128 * completed, and that we should be able to queue a command now.
130 * Note that the prior mid-layer assumption that any host could
131 * always queue at least one command is now broken. The mid-layer
132 * will implement a user specifiable stall (see
133 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
134 * if a command is requeued with no other commands outstanding
135 * either for the device or for the host.
138 case SCSI_MLQUEUE_HOST_BUSY
:
139 host
->host_blocked
= host
->max_host_blocked
;
141 case SCSI_MLQUEUE_DEVICE_BUSY
:
142 device
->device_blocked
= device
->max_device_blocked
;
144 case SCSI_MLQUEUE_TARGET_BUSY
:
145 starget
->target_blocked
= starget
->max_target_blocked
;
150 * Decrement the counters, since these commands are no longer
151 * active on the host/device.
153 scsi_device_unbusy(device
);
156 * Requeue this command. It will go before all other commands
157 * that are already in the queue.
159 * NOTE: there is magic here about the way the queue is plugged if
160 * we have no outstanding commands.
162 * Although we *don't* plug the queue, we call the request
163 * function. The SCSI request function detects the blocked condition
164 * and plugs the queue appropriately.
166 spin_lock_irqsave(q
->queue_lock
, flags
);
167 blk_requeue_request(q
, cmd
->request
);
168 spin_unlock_irqrestore(q
->queue_lock
, flags
);
176 * scsi_execute - insert request and wait for the result
179 * @data_direction: data direction
180 * @buffer: data buffer
181 * @bufflen: len of buffer
182 * @sense: optional sense buffer
183 * @timeout: request timeout in seconds
184 * @retries: number of times to retry request
185 * @flags: or into request flags;
187 * returns the req->errors value which is the scsi_cmnd result
190 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
191 int data_direction
, void *buffer
, unsigned bufflen
,
192 unsigned char *sense
, int timeout
, int retries
, int flags
)
195 int write
= (data_direction
== DMA_TO_DEVICE
);
196 int ret
= DRIVER_ERROR
<< 24;
198 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
200 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
201 buffer
, bufflen
, __GFP_WAIT
))
204 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
205 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
208 req
->retries
= retries
;
209 req
->timeout
= timeout
;
210 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
211 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
214 * head injection *required* here otherwise quiesce won't work
216 blk_execute_rq(req
->q
, NULL
, req
, 1);
219 * Some devices (USB mass-storage in particular) may transfer
220 * garbage data together with a residue indicating that the data
221 * is invalid. Prevent the garbage from being misinterpreted
222 * and prevent security leaks by zeroing out the excess data.
224 if (unlikely(req
->data_len
> 0 && req
->data_len
<= bufflen
))
225 memset(buffer
+ (bufflen
- req
->data_len
), 0, req
->data_len
);
229 blk_put_request(req
);
233 EXPORT_SYMBOL(scsi_execute
);
236 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
237 int data_direction
, void *buffer
, unsigned bufflen
,
238 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
244 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
246 return DRIVER_ERROR
<< 24;
248 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
249 sense
, timeout
, retries
, 0);
251 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
256 EXPORT_SYMBOL(scsi_execute_req
);
258 struct scsi_io_context
{
260 void (*done
)(void *data
, char *sense
, int result
, int resid
);
261 char sense
[SCSI_SENSE_BUFFERSIZE
];
264 static struct kmem_cache
*scsi_io_context_cache
;
266 static void scsi_end_async(struct request
*req
, int uptodate
)
268 struct scsi_io_context
*sioc
= req
->end_io_data
;
271 sioc
->done(sioc
->data
, sioc
->sense
, req
->errors
, req
->data_len
);
273 kmem_cache_free(scsi_io_context_cache
, sioc
);
274 __blk_put_request(req
->q
, req
);
277 static int scsi_merge_bio(struct request
*rq
, struct bio
*bio
)
279 struct request_queue
*q
= rq
->q
;
281 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
282 if (rq_data_dir(rq
) == WRITE
)
283 bio
->bi_rw
|= (1 << BIO_RW
);
284 blk_queue_bounce(q
, &bio
);
286 return blk_rq_append_bio(q
, rq
, bio
);
289 static void scsi_bi_endio(struct bio
*bio
, int error
)
295 * scsi_req_map_sg - map a scatterlist into a request
296 * @rq: request to fill
298 * @nsegs: number of elements
299 * @bufflen: len of buffer
300 * @gfp: memory allocation flags
302 * scsi_req_map_sg maps a scatterlist into a request so that the
303 * request can be sent to the block layer. We do not trust the scatterlist
304 * sent to use, as some ULDs use that struct to only organize the pages.
306 static int scsi_req_map_sg(struct request
*rq
, struct scatterlist
*sgl
,
307 int nsegs
, unsigned bufflen
, gfp_t gfp
)
309 struct request_queue
*q
= rq
->q
;
310 int nr_pages
= (bufflen
+ sgl
[0].offset
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
311 unsigned int data_len
= bufflen
, len
, bytes
, off
;
312 struct scatterlist
*sg
;
314 struct bio
*bio
= NULL
;
315 int i
, err
, nr_vecs
= 0;
317 for_each_sg(sgl
, sg
, nsegs
, i
) {
322 while (len
> 0 && data_len
> 0) {
324 * sg sends a scatterlist that is larger than
325 * the data_len it wants transferred for certain
328 bytes
= min_t(unsigned int, len
, PAGE_SIZE
- off
);
329 bytes
= min(bytes
, data_len
);
332 nr_vecs
= min_t(int, BIO_MAX_PAGES
, nr_pages
);
335 bio
= bio_alloc(gfp
, nr_vecs
);
340 bio
->bi_end_io
= scsi_bi_endio
;
343 if (bio_add_pc_page(q
, bio
, page
, bytes
, off
) !=
350 if (bio
->bi_vcnt
>= nr_vecs
) {
351 err
= scsi_merge_bio(rq
, bio
);
366 rq
->buffer
= rq
->data
= NULL
;
367 rq
->data_len
= bufflen
;
371 while ((bio
= rq
->bio
) != NULL
) {
372 rq
->bio
= bio
->bi_next
;
374 * call endio instead of bio_put incase it was bounced
383 * scsi_execute_async - insert request
386 * @cmd_len: length of scsi cdb
387 * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
388 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
389 * @bufflen: len of buffer
390 * @use_sg: if buffer is a scatterlist this is the number of elements
391 * @timeout: request timeout in seconds
392 * @retries: number of times to retry request
393 * @privdata: data passed to done()
394 * @done: callback function when done
395 * @gfp: memory allocation flags
397 int scsi_execute_async(struct scsi_device
*sdev
, const unsigned char *cmd
,
398 int cmd_len
, int data_direction
, void *buffer
, unsigned bufflen
,
399 int use_sg
, int timeout
, int retries
, void *privdata
,
400 void (*done
)(void *, char *, int, int), gfp_t gfp
)
403 struct scsi_io_context
*sioc
;
405 int write
= (data_direction
== DMA_TO_DEVICE
);
407 sioc
= kmem_cache_zalloc(scsi_io_context_cache
, gfp
);
409 return DRIVER_ERROR
<< 24;
411 req
= blk_get_request(sdev
->request_queue
, write
, gfp
);
414 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
415 req
->cmd_flags
|= REQ_QUIET
;
418 err
= scsi_req_map_sg(req
, buffer
, use_sg
, bufflen
, gfp
);
420 err
= blk_rq_map_kern(req
->q
, req
, buffer
, bufflen
, gfp
);
425 req
->cmd_len
= cmd_len
;
426 memset(req
->cmd
, 0, BLK_MAX_CDB
); /* ATAPI hates garbage after CDB */
427 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
428 req
->sense
= sioc
->sense
;
430 req
->timeout
= timeout
;
431 req
->retries
= retries
;
432 req
->end_io_data
= sioc
;
434 sioc
->data
= privdata
;
437 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
441 blk_put_request(req
);
443 kmem_cache_free(scsi_io_context_cache
, sioc
);
444 return DRIVER_ERROR
<< 24;
446 EXPORT_SYMBOL_GPL(scsi_execute_async
);
449 * Function: scsi_init_cmd_errh()
451 * Purpose: Initialize cmd fields related to error handling.
453 * Arguments: cmd - command that is ready to be queued.
455 * Notes: This function has the job of initializing a number of
456 * fields related to error handling. Typically this will
457 * be called once for each command, as required.
459 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
461 cmd
->serial_number
= 0;
462 scsi_set_resid(cmd
, 0);
463 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
464 if (cmd
->cmd_len
== 0)
465 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
468 void scsi_device_unbusy(struct scsi_device
*sdev
)
470 struct Scsi_Host
*shost
= sdev
->host
;
471 struct scsi_target
*starget
= scsi_target(sdev
);
474 spin_lock_irqsave(shost
->host_lock
, flags
);
476 starget
->target_busy
--;
477 if (unlikely(scsi_host_in_recovery(shost
) &&
478 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
479 scsi_eh_wakeup(shost
);
480 spin_unlock(shost
->host_lock
);
481 spin_lock(sdev
->request_queue
->queue_lock
);
483 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
487 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
488 * and call blk_run_queue for all the scsi_devices on the target -
489 * including current_sdev first.
491 * Called with *no* scsi locks held.
493 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
495 struct Scsi_Host
*shost
= current_sdev
->host
;
496 struct scsi_device
*sdev
, *tmp
;
497 struct scsi_target
*starget
= scsi_target(current_sdev
);
500 spin_lock_irqsave(shost
->host_lock
, flags
);
501 starget
->starget_sdev_user
= NULL
;
502 spin_unlock_irqrestore(shost
->host_lock
, flags
);
505 * Call blk_run_queue for all LUNs on the target, starting with
506 * current_sdev. We race with others (to set starget_sdev_user),
507 * but in most cases, we will be first. Ideally, each LU on the
508 * target would get some limited time or requests on the target.
510 blk_run_queue(current_sdev
->request_queue
);
512 spin_lock_irqsave(shost
->host_lock
, flags
);
513 if (starget
->starget_sdev_user
)
515 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
516 same_target_siblings
) {
517 if (sdev
== current_sdev
)
519 if (scsi_device_get(sdev
))
522 spin_unlock_irqrestore(shost
->host_lock
, flags
);
523 blk_run_queue(sdev
->request_queue
);
524 spin_lock_irqsave(shost
->host_lock
, flags
);
526 scsi_device_put(sdev
);
529 spin_unlock_irqrestore(shost
->host_lock
, flags
);
532 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
534 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
540 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
542 return ((starget
->can_queue
> 0 &&
543 starget
->target_busy
>= starget
->can_queue
) ||
544 starget
->target_blocked
);
547 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
549 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
550 shost
->host_blocked
|| shost
->host_self_blocked
)
557 * Function: scsi_run_queue()
559 * Purpose: Select a proper request queue to serve next
561 * Arguments: q - last request's queue
565 * Notes: The previous command was completely finished, start
566 * a new one if possible.
568 static void scsi_run_queue(struct request_queue
*q
)
570 struct scsi_device
*sdev
= q
->queuedata
;
571 struct Scsi_Host
*shost
= sdev
->host
;
572 LIST_HEAD(starved_list
);
575 if (scsi_target(sdev
)->single_lun
)
576 scsi_single_lun_run(sdev
);
578 spin_lock_irqsave(shost
->host_lock
, flags
);
579 list_splice_init(&shost
->starved_list
, &starved_list
);
581 while (!list_empty(&starved_list
)) {
585 * As long as shost is accepting commands and we have
586 * starved queues, call blk_run_queue. scsi_request_fn
587 * drops the queue_lock and can add us back to the
590 * host_lock protects the starved_list and starved_entry.
591 * scsi_request_fn must get the host_lock before checking
592 * or modifying starved_list or starved_entry.
594 if (scsi_host_is_busy(shost
))
597 sdev
= list_entry(starved_list
.next
,
598 struct scsi_device
, starved_entry
);
599 list_del_init(&sdev
->starved_entry
);
600 if (scsi_target_is_busy(scsi_target(sdev
))) {
601 list_move_tail(&sdev
->starved_entry
,
602 &shost
->starved_list
);
606 spin_unlock(shost
->host_lock
);
608 spin_lock(sdev
->request_queue
->queue_lock
);
609 flagset
= test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
610 !test_bit(QUEUE_FLAG_REENTER
,
611 &sdev
->request_queue
->queue_flags
);
613 queue_flag_set(QUEUE_FLAG_REENTER
, sdev
->request_queue
);
614 __blk_run_queue(sdev
->request_queue
);
616 queue_flag_clear(QUEUE_FLAG_REENTER
, sdev
->request_queue
);
617 spin_unlock(sdev
->request_queue
->queue_lock
);
619 spin_lock(shost
->host_lock
);
621 /* put any unprocessed entries back */
622 list_splice(&starved_list
, &shost
->starved_list
);
623 spin_unlock_irqrestore(shost
->host_lock
, flags
);
629 * Function: scsi_requeue_command()
631 * Purpose: Handle post-processing of completed commands.
633 * Arguments: q - queue to operate on
634 * cmd - command that may need to be requeued.
638 * Notes: After command completion, there may be blocks left
639 * over which weren't finished by the previous command
640 * this can be for a number of reasons - the main one is
641 * I/O errors in the middle of the request, in which case
642 * we need to request the blocks that come after the bad
644 * Notes: Upon return, cmd is a stale pointer.
646 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
648 struct request
*req
= cmd
->request
;
651 spin_lock_irqsave(q
->queue_lock
, flags
);
652 scsi_unprep_request(req
);
653 blk_requeue_request(q
, req
);
654 spin_unlock_irqrestore(q
->queue_lock
, flags
);
659 void scsi_next_command(struct scsi_cmnd
*cmd
)
661 struct scsi_device
*sdev
= cmd
->device
;
662 struct request_queue
*q
= sdev
->request_queue
;
664 /* need to hold a reference on the device before we let go of the cmd */
665 get_device(&sdev
->sdev_gendev
);
667 scsi_put_command(cmd
);
670 /* ok to remove device now */
671 put_device(&sdev
->sdev_gendev
);
674 void scsi_run_host_queues(struct Scsi_Host
*shost
)
676 struct scsi_device
*sdev
;
678 shost_for_each_device(sdev
, shost
)
679 scsi_run_queue(sdev
->request_queue
);
683 * Function: scsi_end_request()
685 * Purpose: Post-processing of completed commands (usually invoked at end
686 * of upper level post-processing and scsi_io_completion).
688 * Arguments: cmd - command that is complete.
689 * error - 0 if I/O indicates success, < 0 for I/O error.
690 * bytes - number of bytes of completed I/O
691 * requeue - indicates whether we should requeue leftovers.
693 * Lock status: Assumed that lock is not held upon entry.
695 * Returns: cmd if requeue required, NULL otherwise.
697 * Notes: This is called for block device requests in order to
698 * mark some number of sectors as complete.
700 * We are guaranteeing that the request queue will be goosed
701 * at some point during this call.
702 * Notes: If cmd was requeued, upon return it will be a stale pointer.
704 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int error
,
705 int bytes
, int requeue
)
707 struct request_queue
*q
= cmd
->device
->request_queue
;
708 struct request
*req
= cmd
->request
;
711 * If there are blocks left over at the end, set up the command
712 * to queue the remainder of them.
714 if (blk_end_request(req
, error
, bytes
)) {
715 int leftover
= (req
->hard_nr_sectors
<< 9);
717 if (blk_pc_request(req
))
718 leftover
= req
->data_len
;
720 /* kill remainder if no retrys */
721 if (error
&& scsi_noretry_cmd(cmd
))
722 blk_end_request(req
, error
, leftover
);
726 * Bleah. Leftovers again. Stick the
727 * leftovers in the front of the
728 * queue, and goose the queue again.
730 scsi_requeue_command(q
, cmd
);
738 * This will goose the queue request function at the end, so we don't
739 * need to worry about launching another command.
741 scsi_next_command(cmd
);
745 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
749 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
754 index
= get_count_order(nents
) - 3;
759 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
761 struct scsi_host_sg_pool
*sgp
;
763 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
764 mempool_free(sgl
, sgp
->pool
);
767 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
769 struct scsi_host_sg_pool
*sgp
;
771 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
772 return mempool_alloc(sgp
->pool
, gfp_mask
);
775 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
782 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
783 gfp_mask
, scsi_sg_alloc
);
785 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
791 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
793 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
797 * Function: scsi_release_buffers()
799 * Purpose: Completion processing for block device I/O requests.
801 * Arguments: cmd - command that we are bailing.
803 * Lock status: Assumed that no lock is held upon entry.
807 * Notes: In the event that an upper level driver rejects a
808 * command, we must release resources allocated during
809 * the __init_io() function. Primarily this would involve
810 * the scatter-gather table, and potentially any bounce
813 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
815 if (cmd
->sdb
.table
.nents
)
816 scsi_free_sgtable(&cmd
->sdb
);
818 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
820 if (scsi_bidi_cmnd(cmd
)) {
821 struct scsi_data_buffer
*bidi_sdb
=
822 cmd
->request
->next_rq
->special
;
823 scsi_free_sgtable(bidi_sdb
);
824 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
825 cmd
->request
->next_rq
->special
= NULL
;
828 if (scsi_prot_sg_count(cmd
))
829 scsi_free_sgtable(cmd
->prot_sdb
);
831 EXPORT_SYMBOL(scsi_release_buffers
);
834 * Bidi commands Must be complete as a whole, both sides at once.
835 * If part of the bytes were written and lld returned
836 * scsi_in()->resid and/or scsi_out()->resid this information will be left
837 * in req->data_len and req->next_rq->data_len. The upper-layer driver can
838 * decide what to do with this information.
840 static void scsi_end_bidi_request(struct scsi_cmnd
*cmd
)
842 struct request
*req
= cmd
->request
;
843 unsigned int dlen
= req
->data_len
;
844 unsigned int next_dlen
= req
->next_rq
->data_len
;
846 req
->data_len
= scsi_out(cmd
)->resid
;
847 req
->next_rq
->data_len
= scsi_in(cmd
)->resid
;
849 /* The req and req->next_rq have not been completed */
850 BUG_ON(blk_end_bidi_request(req
, 0, dlen
, next_dlen
));
852 scsi_release_buffers(cmd
);
855 * This will goose the queue request function at the end, so we don't
856 * need to worry about launching another command.
858 scsi_next_command(cmd
);
862 * Function: scsi_io_completion()
864 * Purpose: Completion processing for block device I/O requests.
866 * Arguments: cmd - command that is finished.
868 * Lock status: Assumed that no lock is held upon entry.
872 * Notes: This function is matched in terms of capabilities to
873 * the function that created the scatter-gather list.
874 * In other words, if there are no bounce buffers
875 * (the normal case for most drivers), we don't need
876 * the logic to deal with cleaning up afterwards.
878 * We must call scsi_end_request(). This will finish off
879 * the specified number of sectors. If we are done, the
880 * command block will be released and the queue function
881 * will be goosed. If we are not done then we have to
882 * figure out what to do next:
884 * a) We can call scsi_requeue_command(). The request
885 * will be unprepared and put back on the queue. Then
886 * a new command will be created for it. This should
887 * be used if we made forward progress, or if we want
888 * to switch from READ(10) to READ(6) for example.
890 * b) We can call scsi_queue_insert(). The request will
891 * be put back on the queue and retried using the same
892 * command as before, possibly after a delay.
894 * c) We can call blk_end_request() with -EIO to fail
895 * the remainder of the request.
897 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
899 int result
= cmd
->result
;
901 struct request_queue
*q
= cmd
->device
->request_queue
;
902 struct request
*req
= cmd
->request
;
904 struct scsi_sense_hdr sshdr
;
906 int sense_deferred
= 0;
907 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
908 ACTION_DELAYED_RETRY
} action
;
909 char *description
= NULL
;
912 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
914 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
917 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
918 req
->errors
= result
;
920 if (sense_valid
&& req
->sense
) {
922 * SG_IO wants current and deferred errors
924 int len
= 8 + cmd
->sense_buffer
[7];
926 if (len
> SCSI_SENSE_BUFFERSIZE
)
927 len
= SCSI_SENSE_BUFFERSIZE
;
928 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
929 req
->sense_len
= len
;
934 if (scsi_bidi_cmnd(cmd
)) {
935 /* will also release_buffers */
936 scsi_end_bidi_request(cmd
);
939 req
->data_len
= scsi_get_resid(cmd
);
942 BUG_ON(blk_bidi_rq(req
)); /* bidi not support for !blk_pc_request yet */
943 scsi_release_buffers(cmd
);
946 * Next deal with any sectors which we were able to correctly
949 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
951 req
->nr_sectors
, good_bytes
));
953 /* A number of bytes were successfully read. If there
954 * are leftovers and there is some kind of error
955 * (result != 0), retry the rest.
957 if (scsi_end_request(cmd
, error
, good_bytes
, result
== 0) == NULL
)
959 this_count
= blk_rq_bytes(req
);
961 if (host_byte(result
) == DID_RESET
) {
962 /* Third party bus reset or reset for error recovery
963 * reasons. Just retry the command and see what
966 action
= ACTION_RETRY
;
967 } else if (sense_valid
&& !sense_deferred
) {
968 switch (sshdr
.sense_key
) {
970 if (cmd
->device
->removable
) {
971 /* Detected disc change. Set a bit
972 * and quietly refuse further access.
974 cmd
->device
->changed
= 1;
975 description
= "Media Changed";
976 action
= ACTION_FAIL
;
978 /* Must have been a power glitch, or a
979 * bus reset. Could not have been a
980 * media change, so we just retry the
981 * command and see what happens.
983 action
= ACTION_RETRY
;
986 case ILLEGAL_REQUEST
:
987 /* If we had an ILLEGAL REQUEST returned, then
988 * we may have performed an unsupported
989 * command. The only thing this should be
990 * would be a ten byte read where only a six
991 * byte read was supported. Also, on a system
992 * where READ CAPACITY failed, we may have
993 * read past the end of the disk.
995 if ((cmd
->device
->use_10_for_rw
&&
996 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
997 (cmd
->cmnd
[0] == READ_10
||
998 cmd
->cmnd
[0] == WRITE_10
)) {
999 /* This will issue a new 6-byte command. */
1000 cmd
->device
->use_10_for_rw
= 0;
1001 action
= ACTION_REPREP
;
1003 action
= ACTION_FAIL
;
1005 case ABORTED_COMMAND
:
1006 if (sshdr
.asc
== 0x10) { /* DIF */
1007 action
= ACTION_FAIL
;
1008 description
= "Data Integrity Failure";
1010 action
= ACTION_RETRY
;
1013 /* If the device is in the process of becoming
1014 * ready, or has a temporary blockage, retry.
1016 if (sshdr
.asc
== 0x04) {
1017 switch (sshdr
.ascq
) {
1018 case 0x01: /* becoming ready */
1019 case 0x04: /* format in progress */
1020 case 0x05: /* rebuild in progress */
1021 case 0x06: /* recalculation in progress */
1022 case 0x07: /* operation in progress */
1023 case 0x08: /* Long write in progress */
1024 case 0x09: /* self test in progress */
1025 action
= ACTION_DELAYED_RETRY
;
1029 description
= "Device not ready";
1030 action
= ACTION_FAIL
;
1033 case VOLUME_OVERFLOW
:
1034 /* See SSC3rXX or current. */
1035 action
= ACTION_FAIL
;
1038 description
= "Unhandled sense code";
1039 action
= ACTION_FAIL
;
1043 description
= "Unhandled error code";
1044 action
= ACTION_FAIL
;
1049 /* Give up and fail the remainder of the request */
1050 if (!(req
->cmd_flags
& REQ_QUIET
)) {
1052 scmd_printk(KERN_INFO
, cmd
, "%s",
1054 scsi_print_result(cmd
);
1055 if (driver_byte(result
) & DRIVER_SENSE
)
1056 scsi_print_sense("", cmd
);
1058 blk_end_request(req
, -EIO
, blk_rq_bytes(req
));
1059 scsi_next_command(cmd
);
1062 /* Unprep the request and put it back at the head of the queue.
1063 * A new command will be prepared and issued.
1065 scsi_requeue_command(q
, cmd
);
1068 /* Retry the same command immediately */
1069 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1071 case ACTION_DELAYED_RETRY
:
1072 /* Retry the same command after a delay */
1073 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1078 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
1084 * If sg table allocation fails, requeue request later.
1086 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
1088 return BLKPREP_DEFER
;
1094 * Next, walk the list, and fill in the addresses and sizes of
1097 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1098 BUG_ON(count
> sdb
->table
.nents
);
1099 sdb
->table
.nents
= count
;
1100 if (blk_pc_request(req
))
1101 sdb
->length
= req
->data_len
;
1103 sdb
->length
= req
->nr_sectors
<< 9;
1108 * Function: scsi_init_io()
1110 * Purpose: SCSI I/O initialize function.
1112 * Arguments: cmd - Command descriptor we wish to initialize
1114 * Returns: 0 on success
1115 * BLKPREP_DEFER if the failure is retryable
1116 * BLKPREP_KILL if the failure is fatal
1118 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
1120 int error
= scsi_init_sgtable(cmd
->request
, &cmd
->sdb
, gfp_mask
);
1124 if (blk_bidi_rq(cmd
->request
)) {
1125 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
1126 scsi_sdb_cache
, GFP_ATOMIC
);
1128 error
= BLKPREP_DEFER
;
1132 cmd
->request
->next_rq
->special
= bidi_sdb
;
1133 error
= scsi_init_sgtable(cmd
->request
->next_rq
, bidi_sdb
,
1139 if (blk_integrity_rq(cmd
->request
)) {
1140 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1143 BUG_ON(prot_sdb
== NULL
);
1144 ivecs
= blk_rq_count_integrity_sg(cmd
->request
);
1146 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1147 error
= BLKPREP_DEFER
;
1151 count
= blk_rq_map_integrity_sg(cmd
->request
,
1152 prot_sdb
->table
.sgl
);
1153 BUG_ON(unlikely(count
> ivecs
));
1155 cmd
->prot_sdb
= prot_sdb
;
1156 cmd
->prot_sdb
->table
.nents
= count
;
1162 scsi_release_buffers(cmd
);
1163 if (error
== BLKPREP_KILL
)
1164 scsi_put_command(cmd
);
1165 else /* BLKPREP_DEFER */
1166 scsi_unprep_request(cmd
->request
);
1170 EXPORT_SYMBOL(scsi_init_io
);
1172 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1173 struct request
*req
)
1175 struct scsi_cmnd
*cmd
;
1177 if (!req
->special
) {
1178 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1186 /* pull a tag out of the request if we have one */
1187 cmd
->tag
= req
->tag
;
1190 cmd
->cmnd
= req
->cmd
;
1195 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1197 struct scsi_cmnd
*cmd
;
1198 int ret
= scsi_prep_state_check(sdev
, req
);
1200 if (ret
!= BLKPREP_OK
)
1203 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1205 return BLKPREP_DEFER
;
1208 * BLOCK_PC requests may transfer data, in which case they must
1209 * a bio attached to them. Or they might contain a SCSI command
1210 * that does not transfer data, in which case they may optionally
1211 * submit a request without an attached bio.
1216 BUG_ON(!req
->nr_phys_segments
);
1218 ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1222 BUG_ON(req
->data_len
);
1225 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1229 cmd
->cmd_len
= req
->cmd_len
;
1231 cmd
->sc_data_direction
= DMA_NONE
;
1232 else if (rq_data_dir(req
) == WRITE
)
1233 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1235 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1237 cmd
->transfersize
= req
->data_len
;
1238 cmd
->allowed
= req
->retries
;
1241 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1244 * Setup a REQ_TYPE_FS command. These are simple read/write request
1245 * from filesystems that still need to be translated to SCSI CDBs from
1248 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1250 struct scsi_cmnd
*cmd
;
1251 int ret
= scsi_prep_state_check(sdev
, req
);
1253 if (ret
!= BLKPREP_OK
)
1256 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1257 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1258 ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1259 if (ret
!= BLKPREP_OK
)
1264 * Filesystem requests must transfer data.
1266 BUG_ON(!req
->nr_phys_segments
);
1268 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1270 return BLKPREP_DEFER
;
1272 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1273 return scsi_init_io(cmd
, GFP_ATOMIC
);
1275 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1277 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1279 int ret
= BLKPREP_OK
;
1282 * If the device is not in running state we will reject some
1285 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1286 switch (sdev
->sdev_state
) {
1289 * If the device is offline we refuse to process any
1290 * commands. The device must be brought online
1291 * before trying any recovery commands.
1293 sdev_printk(KERN_ERR
, sdev
,
1294 "rejecting I/O to offline device\n");
1299 * If the device is fully deleted, we refuse to
1300 * process any commands as well.
1302 sdev_printk(KERN_ERR
, sdev
,
1303 "rejecting I/O to dead device\n");
1308 case SDEV_CREATED_BLOCK
:
1310 * If the devices is blocked we defer normal commands.
1312 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1313 ret
= BLKPREP_DEFER
;
1317 * For any other not fully online state we only allow
1318 * special commands. In particular any user initiated
1319 * command is not allowed.
1321 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1328 EXPORT_SYMBOL(scsi_prep_state_check
);
1330 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1332 struct scsi_device
*sdev
= q
->queuedata
;
1336 req
->errors
= DID_NO_CONNECT
<< 16;
1337 /* release the command and kill it */
1339 struct scsi_cmnd
*cmd
= req
->special
;
1340 scsi_release_buffers(cmd
);
1341 scsi_put_command(cmd
);
1342 req
->special
= NULL
;
1347 * If we defer, the elv_next_request() returns NULL, but the
1348 * queue must be restarted, so we plug here if no returning
1349 * command will automatically do that.
1351 if (sdev
->device_busy
== 0)
1355 req
->cmd_flags
|= REQ_DONTPREP
;
1360 EXPORT_SYMBOL(scsi_prep_return
);
1362 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1364 struct scsi_device
*sdev
= q
->queuedata
;
1365 int ret
= BLKPREP_KILL
;
1367 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1368 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1369 return scsi_prep_return(q
, req
, ret
);
1373 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1376 * Called with the queue_lock held.
1378 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1379 struct scsi_device
*sdev
)
1381 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1383 * unblock after device_blocked iterates to zero
1385 if (--sdev
->device_blocked
== 0) {
1387 sdev_printk(KERN_INFO
, sdev
,
1388 "unblocking device at zero depth\n"));
1394 if (scsi_device_is_busy(sdev
))
1402 * scsi_target_queue_ready: checks if there we can send commands to target
1403 * @sdev: scsi device on starget to check.
1405 * Called with the host lock held.
1407 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1408 struct scsi_device
*sdev
)
1410 struct scsi_target
*starget
= scsi_target(sdev
);
1412 if (starget
->single_lun
) {
1413 if (starget
->starget_sdev_user
&&
1414 starget
->starget_sdev_user
!= sdev
)
1416 starget
->starget_sdev_user
= sdev
;
1419 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1421 * unblock after target_blocked iterates to zero
1423 if (--starget
->target_blocked
== 0) {
1424 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1425 "unblocking target at zero depth\n"));
1427 blk_plug_device(sdev
->request_queue
);
1432 if (scsi_target_is_busy(starget
)) {
1433 if (list_empty(&sdev
->starved_entry
)) {
1434 list_add_tail(&sdev
->starved_entry
,
1435 &shost
->starved_list
);
1440 /* We're OK to process the command, so we can't be starved */
1441 if (!list_empty(&sdev
->starved_entry
))
1442 list_del_init(&sdev
->starved_entry
);
1447 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1448 * return 0. We must end up running the queue again whenever 0 is
1449 * returned, else IO can hang.
1451 * Called with host_lock held.
1453 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1454 struct Scsi_Host
*shost
,
1455 struct scsi_device
*sdev
)
1457 if (scsi_host_in_recovery(shost
))
1459 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1461 * unblock after host_blocked iterates to zero
1463 if (--shost
->host_blocked
== 0) {
1465 printk("scsi%d unblocking host at zero depth\n",
1471 if (scsi_host_is_busy(shost
)) {
1472 if (list_empty(&sdev
->starved_entry
))
1473 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1477 /* We're OK to process the command, so we can't be starved */
1478 if (!list_empty(&sdev
->starved_entry
))
1479 list_del_init(&sdev
->starved_entry
);
1485 * Busy state exporting function for request stacking drivers.
1487 * For efficiency, no lock is taken to check the busy state of
1488 * shost/starget/sdev, since the returned value is not guaranteed and
1489 * may be changed after request stacking drivers call the function,
1490 * regardless of taking lock or not.
1492 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1493 * (e.g. !sdev), scsi needs to return 'not busy'.
1494 * Otherwise, request stacking drivers may hold requests forever.
1496 static int scsi_lld_busy(struct request_queue
*q
)
1498 struct scsi_device
*sdev
= q
->queuedata
;
1499 struct Scsi_Host
*shost
;
1500 struct scsi_target
*starget
;
1506 starget
= scsi_target(sdev
);
1508 if (scsi_host_in_recovery(shost
) || scsi_host_is_busy(shost
) ||
1509 scsi_target_is_busy(starget
) || scsi_device_is_busy(sdev
))
1516 * Kill a request for a dead device
1518 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1520 struct scsi_cmnd
*cmd
= req
->special
;
1521 struct scsi_device
*sdev
= cmd
->device
;
1522 struct scsi_target
*starget
= scsi_target(sdev
);
1523 struct Scsi_Host
*shost
= sdev
->host
;
1525 blkdev_dequeue_request(req
);
1527 if (unlikely(cmd
== NULL
)) {
1528 printk(KERN_CRIT
"impossible request in %s.\n",
1533 scsi_init_cmd_errh(cmd
);
1534 cmd
->result
= DID_NO_CONNECT
<< 16;
1535 atomic_inc(&cmd
->device
->iorequest_cnt
);
1538 * SCSI request completion path will do scsi_device_unbusy(),
1539 * bump busy counts. To bump the counters, we need to dance
1540 * with the locks as normal issue path does.
1542 sdev
->device_busy
++;
1543 spin_unlock(sdev
->request_queue
->queue_lock
);
1544 spin_lock(shost
->host_lock
);
1546 starget
->target_busy
++;
1547 spin_unlock(shost
->host_lock
);
1548 spin_lock(sdev
->request_queue
->queue_lock
);
1550 blk_complete_request(req
);
1553 static void scsi_softirq_done(struct request
*rq
)
1555 struct scsi_cmnd
*cmd
= rq
->special
;
1556 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1559 INIT_LIST_HEAD(&cmd
->eh_entry
);
1562 * Set the serial numbers back to zero
1564 cmd
->serial_number
= 0;
1566 atomic_inc(&cmd
->device
->iodone_cnt
);
1568 atomic_inc(&cmd
->device
->ioerr_cnt
);
1570 disposition
= scsi_decide_disposition(cmd
);
1571 if (disposition
!= SUCCESS
&&
1572 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1573 sdev_printk(KERN_ERR
, cmd
->device
,
1574 "timing out command, waited %lus\n",
1576 disposition
= SUCCESS
;
1579 scsi_log_completion(cmd
, disposition
);
1581 switch (disposition
) {
1583 scsi_finish_command(cmd
);
1586 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1588 case ADD_TO_MLQUEUE
:
1589 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1592 if (!scsi_eh_scmd_add(cmd
, 0))
1593 scsi_finish_command(cmd
);
1598 * Function: scsi_request_fn()
1600 * Purpose: Main strategy routine for SCSI.
1602 * Arguments: q - Pointer to actual queue.
1606 * Lock status: IO request lock assumed to be held when called.
1608 static void scsi_request_fn(struct request_queue
*q
)
1610 struct scsi_device
*sdev
= q
->queuedata
;
1611 struct Scsi_Host
*shost
;
1612 struct scsi_cmnd
*cmd
;
1613 struct request
*req
;
1616 printk("scsi: killing requests for dead queue\n");
1617 while ((req
= elv_next_request(q
)) != NULL
)
1618 scsi_kill_request(req
, q
);
1622 if(!get_device(&sdev
->sdev_gendev
))
1623 /* We must be tearing the block queue down already */
1627 * To start with, we keep looping until the queue is empty, or until
1628 * the host is no longer able to accept any more requests.
1631 while (!blk_queue_plugged(q
)) {
1634 * get next queueable request. We do this early to make sure
1635 * that the request is fully prepared even if we cannot
1638 req
= elv_next_request(q
);
1639 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1642 if (unlikely(!scsi_device_online(sdev
))) {
1643 sdev_printk(KERN_ERR
, sdev
,
1644 "rejecting I/O to offline device\n");
1645 scsi_kill_request(req
, q
);
1651 * Remove the request from the request list.
1653 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1654 blkdev_dequeue_request(req
);
1655 sdev
->device_busy
++;
1657 spin_unlock(q
->queue_lock
);
1659 if (unlikely(cmd
== NULL
)) {
1660 printk(KERN_CRIT
"impossible request in %s.\n"
1661 "please mail a stack trace to "
1662 "linux-scsi@vger.kernel.org\n",
1664 blk_dump_rq_flags(req
, "foo");
1667 spin_lock(shost
->host_lock
);
1670 * We hit this when the driver is using a host wide
1671 * tag map. For device level tag maps the queue_depth check
1672 * in the device ready fn would prevent us from trying
1673 * to allocate a tag. Since the map is a shared host resource
1674 * we add the dev to the starved list so it eventually gets
1675 * a run when a tag is freed.
1677 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1678 if (list_empty(&sdev
->starved_entry
))
1679 list_add_tail(&sdev
->starved_entry
,
1680 &shost
->starved_list
);
1684 if (!scsi_target_queue_ready(shost
, sdev
))
1687 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1690 scsi_target(sdev
)->target_busy
++;
1694 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1695 * take the lock again.
1697 spin_unlock_irq(shost
->host_lock
);
1700 * Finally, initialize any error handling parameters, and set up
1701 * the timers for timeouts.
1703 scsi_init_cmd_errh(cmd
);
1706 * Dispatch the command to the low-level driver.
1708 rtn
= scsi_dispatch_cmd(cmd
);
1709 spin_lock_irq(q
->queue_lock
);
1711 /* we're refusing the command; because of
1712 * the way locks get dropped, we need to
1713 * check here if plugging is required */
1714 if(sdev
->device_busy
== 0)
1724 spin_unlock_irq(shost
->host_lock
);
1727 * lock q, handle tag, requeue req, and decrement device_busy. We
1728 * must return with queue_lock held.
1730 * Decrementing device_busy without checking it is OK, as all such
1731 * cases (host limits or settings) should run the queue at some
1734 spin_lock_irq(q
->queue_lock
);
1735 blk_requeue_request(q
, req
);
1736 sdev
->device_busy
--;
1737 if(sdev
->device_busy
== 0)
1740 /* must be careful here...if we trigger the ->remove() function
1741 * we cannot be holding the q lock */
1742 spin_unlock_irq(q
->queue_lock
);
1743 put_device(&sdev
->sdev_gendev
);
1744 spin_lock_irq(q
->queue_lock
);
1747 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1749 struct device
*host_dev
;
1750 u64 bounce_limit
= 0xffffffff;
1752 if (shost
->unchecked_isa_dma
)
1753 return BLK_BOUNCE_ISA
;
1755 * Platforms with virtual-DMA translation
1756 * hardware have no practical limit.
1758 if (!PCI_DMA_BUS_IS_PHYS
)
1759 return BLK_BOUNCE_ANY
;
1761 host_dev
= scsi_get_device(shost
);
1762 if (host_dev
&& host_dev
->dma_mask
)
1763 bounce_limit
= *host_dev
->dma_mask
;
1765 return bounce_limit
;
1767 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1769 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1770 request_fn_proc
*request_fn
)
1772 struct request_queue
*q
;
1773 struct device
*dev
= shost
->shost_gendev
.parent
;
1775 q
= blk_init_queue(request_fn
, NULL
);
1780 * this limit is imposed by hardware restrictions
1782 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1783 blk_queue_max_phys_segments(q
, SCSI_MAX_SG_CHAIN_SEGMENTS
);
1785 blk_queue_max_sectors(q
, shost
->max_sectors
);
1786 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1787 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1788 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1790 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1792 /* New queue, no concurrency on queue_flags */
1793 if (!shost
->use_clustering
)
1794 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER
, q
);
1797 * set a reasonable default alignment on word boundaries: the
1798 * host and device may alter it using
1799 * blk_queue_update_dma_alignment() later.
1801 blk_queue_dma_alignment(q
, 0x03);
1805 EXPORT_SYMBOL(__scsi_alloc_queue
);
1807 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1809 struct request_queue
*q
;
1811 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1815 blk_queue_prep_rq(q
, scsi_prep_fn
);
1816 blk_queue_softirq_done(q
, scsi_softirq_done
);
1817 blk_queue_rq_timed_out(q
, scsi_times_out
);
1818 blk_queue_lld_busy(q
, scsi_lld_busy
);
1822 void scsi_free_queue(struct request_queue
*q
)
1824 blk_cleanup_queue(q
);
1828 * Function: scsi_block_requests()
1830 * Purpose: Utility function used by low-level drivers to prevent further
1831 * commands from being queued to the device.
1833 * Arguments: shost - Host in question
1837 * Lock status: No locks are assumed held.
1839 * Notes: There is no timer nor any other means by which the requests
1840 * get unblocked other than the low-level driver calling
1841 * scsi_unblock_requests().
1843 void scsi_block_requests(struct Scsi_Host
*shost
)
1845 shost
->host_self_blocked
= 1;
1847 EXPORT_SYMBOL(scsi_block_requests
);
1850 * Function: scsi_unblock_requests()
1852 * Purpose: Utility function used by low-level drivers to allow further
1853 * commands from being queued to the device.
1855 * Arguments: shost - Host in question
1859 * Lock status: No locks are assumed held.
1861 * Notes: There is no timer nor any other means by which the requests
1862 * get unblocked other than the low-level driver calling
1863 * scsi_unblock_requests().
1865 * This is done as an API function so that changes to the
1866 * internals of the scsi mid-layer won't require wholesale
1867 * changes to drivers that use this feature.
1869 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1871 shost
->host_self_blocked
= 0;
1872 scsi_run_host_queues(shost
);
1874 EXPORT_SYMBOL(scsi_unblock_requests
);
1876 int __init
scsi_init_queue(void)
1880 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1881 sizeof(struct scsi_io_context
),
1883 if (!scsi_io_context_cache
) {
1884 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1888 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1889 sizeof(struct scsi_data_buffer
),
1891 if (!scsi_sdb_cache
) {
1892 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1893 goto cleanup_io_context
;
1896 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1897 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1898 int size
= sgp
->size
* sizeof(struct scatterlist
);
1900 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1901 SLAB_HWCACHE_ALIGN
, NULL
);
1903 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1908 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1911 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1920 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1921 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1923 mempool_destroy(sgp
->pool
);
1925 kmem_cache_destroy(sgp
->slab
);
1927 kmem_cache_destroy(scsi_sdb_cache
);
1929 kmem_cache_destroy(scsi_io_context_cache
);
1934 void scsi_exit_queue(void)
1938 kmem_cache_destroy(scsi_io_context_cache
);
1939 kmem_cache_destroy(scsi_sdb_cache
);
1941 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1942 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1943 mempool_destroy(sgp
->pool
);
1944 kmem_cache_destroy(sgp
->slab
);
1949 * scsi_mode_select - issue a mode select
1950 * @sdev: SCSI device to be queried
1951 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1952 * @sp: Save page bit (0 == don't save, 1 == save)
1953 * @modepage: mode page being requested
1954 * @buffer: request buffer (may not be smaller than eight bytes)
1955 * @len: length of request buffer.
1956 * @timeout: command timeout
1957 * @retries: number of retries before failing
1958 * @data: returns a structure abstracting the mode header data
1959 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1960 * must be SCSI_SENSE_BUFFERSIZE big.
1962 * Returns zero if successful; negative error number or scsi
1967 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1968 unsigned char *buffer
, int len
, int timeout
, int retries
,
1969 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1971 unsigned char cmd
[10];
1972 unsigned char *real_buffer
;
1975 memset(cmd
, 0, sizeof(cmd
));
1976 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1978 if (sdev
->use_10_for_ms
) {
1981 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1984 memcpy(real_buffer
+ 8, buffer
, len
);
1988 real_buffer
[2] = data
->medium_type
;
1989 real_buffer
[3] = data
->device_specific
;
1990 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1992 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1993 real_buffer
[7] = data
->block_descriptor_length
;
1995 cmd
[0] = MODE_SELECT_10
;
1999 if (len
> 255 || data
->block_descriptor_length
> 255 ||
2003 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
2006 memcpy(real_buffer
+ 4, buffer
, len
);
2009 real_buffer
[1] = data
->medium_type
;
2010 real_buffer
[2] = data
->device_specific
;
2011 real_buffer
[3] = data
->block_descriptor_length
;
2014 cmd
[0] = MODE_SELECT
;
2018 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
2019 sshdr
, timeout
, retries
);
2023 EXPORT_SYMBOL_GPL(scsi_mode_select
);
2026 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2027 * @sdev: SCSI device to be queried
2028 * @dbd: set if mode sense will allow block descriptors to be returned
2029 * @modepage: mode page being requested
2030 * @buffer: request buffer (may not be smaller than eight bytes)
2031 * @len: length of request buffer.
2032 * @timeout: command timeout
2033 * @retries: number of retries before failing
2034 * @data: returns a structure abstracting the mode header data
2035 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2036 * must be SCSI_SENSE_BUFFERSIZE big.
2038 * Returns zero if unsuccessful, or the header offset (either 4
2039 * or 8 depending on whether a six or ten byte command was
2040 * issued) if successful.
2043 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
2044 unsigned char *buffer
, int len
, int timeout
, int retries
,
2045 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
2047 unsigned char cmd
[12];
2051 struct scsi_sense_hdr my_sshdr
;
2053 memset(data
, 0, sizeof(*data
));
2054 memset(&cmd
[0], 0, 12);
2055 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
2058 /* caller might not be interested in sense, but we need it */
2063 use_10_for_ms
= sdev
->use_10_for_ms
;
2065 if (use_10_for_ms
) {
2069 cmd
[0] = MODE_SENSE_10
;
2076 cmd
[0] = MODE_SENSE
;
2081 memset(buffer
, 0, len
);
2083 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
2084 sshdr
, timeout
, retries
);
2086 /* This code looks awful: what it's doing is making sure an
2087 * ILLEGAL REQUEST sense return identifies the actual command
2088 * byte as the problem. MODE_SENSE commands can return
2089 * ILLEGAL REQUEST if the code page isn't supported */
2091 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
2092 (driver_byte(result
) & DRIVER_SENSE
)) {
2093 if (scsi_sense_valid(sshdr
)) {
2094 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
2095 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
2097 * Invalid command operation code
2099 sdev
->use_10_for_ms
= 0;
2105 if(scsi_status_is_good(result
)) {
2106 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2107 (modepage
== 6 || modepage
== 8))) {
2108 /* Initio breakage? */
2111 data
->medium_type
= 0;
2112 data
->device_specific
= 0;
2114 data
->block_descriptor_length
= 0;
2115 } else if(use_10_for_ms
) {
2116 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2117 data
->medium_type
= buffer
[2];
2118 data
->device_specific
= buffer
[3];
2119 data
->longlba
= buffer
[4] & 0x01;
2120 data
->block_descriptor_length
= buffer
[6]*256
2123 data
->length
= buffer
[0] + 1;
2124 data
->medium_type
= buffer
[1];
2125 data
->device_specific
= buffer
[2];
2126 data
->block_descriptor_length
= buffer
[3];
2128 data
->header_length
= header_length
;
2133 EXPORT_SYMBOL(scsi_mode_sense
);
2136 * scsi_test_unit_ready - test if unit is ready
2137 * @sdev: scsi device to change the state of.
2138 * @timeout: command timeout
2139 * @retries: number of retries before failing
2140 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2141 * returning sense. Make sure that this is cleared before passing
2144 * Returns zero if unsuccessful or an error if TUR failed. For
2145 * removable media, a return of NOT_READY or UNIT_ATTENTION is
2146 * translated to success, with the ->changed flag updated.
2149 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2150 struct scsi_sense_hdr
*sshdr_external
)
2153 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2155 struct scsi_sense_hdr
*sshdr
;
2158 if (!sshdr_external
)
2159 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2161 sshdr
= sshdr_external
;
2163 /* try to eat the UNIT_ATTENTION if there are enough retries */
2165 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2167 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2168 sshdr
->sense_key
== UNIT_ATTENTION
)
2170 } while (scsi_sense_valid(sshdr
) &&
2171 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2174 /* could not allocate sense buffer, so can't process it */
2177 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2178 (sshdr
->sense_key
== UNIT_ATTENTION
||
2179 sshdr
->sense_key
== NOT_READY
)) {
2183 if (!sshdr_external
)
2187 EXPORT_SYMBOL(scsi_test_unit_ready
);
2190 * scsi_device_set_state - Take the given device through the device state model.
2191 * @sdev: scsi device to change the state of.
2192 * @state: state to change to.
2194 * Returns zero if unsuccessful or an error if the requested
2195 * transition is illegal.
2198 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2200 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2202 if (state
== oldstate
)
2208 case SDEV_CREATED_BLOCK
:
2252 case SDEV_CREATED_BLOCK
:
2259 case SDEV_CREATED_BLOCK
:
2294 sdev
->sdev_state
= state
;
2298 SCSI_LOG_ERROR_RECOVERY(1,
2299 sdev_printk(KERN_ERR
, sdev
,
2300 "Illegal state transition %s->%s\n",
2301 scsi_device_state_name(oldstate
),
2302 scsi_device_state_name(state
))
2306 EXPORT_SYMBOL(scsi_device_set_state
);
2309 * sdev_evt_emit - emit a single SCSI device uevent
2310 * @sdev: associated SCSI device
2311 * @evt: event to emit
2313 * Send a single uevent (scsi_event) to the associated scsi_device.
2315 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2320 switch (evt
->evt_type
) {
2321 case SDEV_EVT_MEDIA_CHANGE
:
2322 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2332 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2336 * sdev_evt_thread - send a uevent for each scsi event
2337 * @work: work struct for scsi_device
2339 * Dispatch queued events to their associated scsi_device kobjects
2342 void scsi_evt_thread(struct work_struct
*work
)
2344 struct scsi_device
*sdev
;
2345 LIST_HEAD(event_list
);
2347 sdev
= container_of(work
, struct scsi_device
, event_work
);
2350 struct scsi_event
*evt
;
2351 struct list_head
*this, *tmp
;
2352 unsigned long flags
;
2354 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2355 list_splice_init(&sdev
->event_list
, &event_list
);
2356 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2358 if (list_empty(&event_list
))
2361 list_for_each_safe(this, tmp
, &event_list
) {
2362 evt
= list_entry(this, struct scsi_event
, node
);
2363 list_del(&evt
->node
);
2364 scsi_evt_emit(sdev
, evt
);
2371 * sdev_evt_send - send asserted event to uevent thread
2372 * @sdev: scsi_device event occurred on
2373 * @evt: event to send
2375 * Assert scsi device event asynchronously.
2377 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2379 unsigned long flags
;
2382 /* FIXME: currently this check eliminates all media change events
2383 * for polled devices. Need to update to discriminate between AN
2384 * and polled events */
2385 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2391 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2392 list_add_tail(&evt
->node
, &sdev
->event_list
);
2393 schedule_work(&sdev
->event_work
);
2394 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2396 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2399 * sdev_evt_alloc - allocate a new scsi event
2400 * @evt_type: type of event to allocate
2401 * @gfpflags: GFP flags for allocation
2403 * Allocates and returns a new scsi_event.
2405 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2408 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2412 evt
->evt_type
= evt_type
;
2413 INIT_LIST_HEAD(&evt
->node
);
2415 /* evt_type-specific initialization, if any */
2417 case SDEV_EVT_MEDIA_CHANGE
:
2425 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2428 * sdev_evt_send_simple - send asserted event to uevent thread
2429 * @sdev: scsi_device event occurred on
2430 * @evt_type: type of event to send
2431 * @gfpflags: GFP flags for allocation
2433 * Assert scsi device event asynchronously, given an event type.
2435 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2436 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2438 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2440 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2445 sdev_evt_send(sdev
, evt
);
2447 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2450 * scsi_device_quiesce - Block user issued commands.
2451 * @sdev: scsi device to quiesce.
2453 * This works by trying to transition to the SDEV_QUIESCE state
2454 * (which must be a legal transition). When the device is in this
2455 * state, only special requests will be accepted, all others will
2456 * be deferred. Since special requests may also be requeued requests,
2457 * a successful return doesn't guarantee the device will be
2458 * totally quiescent.
2460 * Must be called with user context, may sleep.
2462 * Returns zero if unsuccessful or an error if not.
2465 scsi_device_quiesce(struct scsi_device
*sdev
)
2467 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2471 scsi_run_queue(sdev
->request_queue
);
2472 while (sdev
->device_busy
) {
2473 msleep_interruptible(200);
2474 scsi_run_queue(sdev
->request_queue
);
2478 EXPORT_SYMBOL(scsi_device_quiesce
);
2481 * scsi_device_resume - Restart user issued commands to a quiesced device.
2482 * @sdev: scsi device to resume.
2484 * Moves the device from quiesced back to running and restarts the
2487 * Must be called with user context, may sleep.
2490 scsi_device_resume(struct scsi_device
*sdev
)
2492 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2494 scsi_run_queue(sdev
->request_queue
);
2496 EXPORT_SYMBOL(scsi_device_resume
);
2499 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2501 scsi_device_quiesce(sdev
);
2505 scsi_target_quiesce(struct scsi_target
*starget
)
2507 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2509 EXPORT_SYMBOL(scsi_target_quiesce
);
2512 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2514 scsi_device_resume(sdev
);
2518 scsi_target_resume(struct scsi_target
*starget
)
2520 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2522 EXPORT_SYMBOL(scsi_target_resume
);
2525 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2526 * @sdev: device to block
2528 * Block request made by scsi lld's to temporarily stop all
2529 * scsi commands on the specified device. Called from interrupt
2530 * or normal process context.
2532 * Returns zero if successful or error if not
2535 * This routine transitions the device to the SDEV_BLOCK state
2536 * (which must be a legal transition). When the device is in this
2537 * state, all commands are deferred until the scsi lld reenables
2538 * the device with scsi_device_unblock or device_block_tmo fires.
2539 * This routine assumes the host_lock is held on entry.
2542 scsi_internal_device_block(struct scsi_device
*sdev
)
2544 struct request_queue
*q
= sdev
->request_queue
;
2545 unsigned long flags
;
2548 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2550 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2557 * The device has transitioned to SDEV_BLOCK. Stop the
2558 * block layer from calling the midlayer with this device's
2561 spin_lock_irqsave(q
->queue_lock
, flags
);
2563 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2567 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2570 * scsi_internal_device_unblock - resume a device after a block request
2571 * @sdev: device to resume
2573 * Called by scsi lld's or the midlayer to restart the device queue
2574 * for the previously suspended scsi device. Called from interrupt or
2575 * normal process context.
2577 * Returns zero if successful or error if not.
2580 * This routine transitions the device to the SDEV_RUNNING state
2581 * (which must be a legal transition) allowing the midlayer to
2582 * goose the queue for this device. This routine assumes the
2583 * host_lock is held upon entry.
2586 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2588 struct request_queue
*q
= sdev
->request_queue
;
2590 unsigned long flags
;
2593 * Try to transition the scsi device to SDEV_RUNNING
2594 * and goose the device queue if successful.
2596 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2598 err
= scsi_device_set_state(sdev
, SDEV_CREATED
);
2604 spin_lock_irqsave(q
->queue_lock
, flags
);
2606 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2610 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2613 device_block(struct scsi_device
*sdev
, void *data
)
2615 scsi_internal_device_block(sdev
);
2619 target_block(struct device
*dev
, void *data
)
2621 if (scsi_is_target_device(dev
))
2622 starget_for_each_device(to_scsi_target(dev
), NULL
,
2628 scsi_target_block(struct device
*dev
)
2630 if (scsi_is_target_device(dev
))
2631 starget_for_each_device(to_scsi_target(dev
), NULL
,
2634 device_for_each_child(dev
, NULL
, target_block
);
2636 EXPORT_SYMBOL_GPL(scsi_target_block
);
2639 device_unblock(struct scsi_device
*sdev
, void *data
)
2641 scsi_internal_device_unblock(sdev
);
2645 target_unblock(struct device
*dev
, void *data
)
2647 if (scsi_is_target_device(dev
))
2648 starget_for_each_device(to_scsi_target(dev
), NULL
,
2654 scsi_target_unblock(struct device
*dev
)
2656 if (scsi_is_target_device(dev
))
2657 starget_for_each_device(to_scsi_target(dev
), NULL
,
2660 device_for_each_child(dev
, NULL
, target_unblock
);
2662 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2665 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2666 * @sgl: scatter-gather list
2667 * @sg_count: number of segments in sg
2668 * @offset: offset in bytes into sg, on return offset into the mapped area
2669 * @len: bytes to map, on return number of bytes mapped
2671 * Returns virtual address of the start of the mapped page
2673 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2674 size_t *offset
, size_t *len
)
2677 size_t sg_len
= 0, len_complete
= 0;
2678 struct scatterlist
*sg
;
2681 WARN_ON(!irqs_disabled());
2683 for_each_sg(sgl
, sg
, sg_count
, i
) {
2684 len_complete
= sg_len
; /* Complete sg-entries */
2685 sg_len
+= sg
->length
;
2686 if (sg_len
> *offset
)
2690 if (unlikely(i
== sg_count
)) {
2691 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2693 __func__
, sg_len
, *offset
, sg_count
);
2698 /* Offset starting from the beginning of first page in this sg-entry */
2699 *offset
= *offset
- len_complete
+ sg
->offset
;
2701 /* Assumption: contiguous pages can be accessed as "page + i" */
2702 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2703 *offset
&= ~PAGE_MASK
;
2705 /* Bytes in this sg-entry from *offset to the end of the page */
2706 sg_len
= PAGE_SIZE
- *offset
;
2710 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2712 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2715 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2716 * @virt: virtual address to be unmapped
2718 void scsi_kunmap_atomic_sg(void *virt
)
2720 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2722 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);