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/blkdev.h>
12 #include <linux/completion.h>
13 #include <linux/kernel.h>
14 #include <linux/mempool.h>
15 #include <linux/slab.h>
16 #include <linux/init.h>
17 #include <linux/pci.h>
18 #include <linux/delay.h>
19 #include <linux/hardirq.h>
20 #include <linux/scatterlist.h>
22 #include <scsi/scsi.h>
23 #include <scsi/scsi_cmnd.h>
24 #include <scsi/scsi_dbg.h>
25 #include <scsi/scsi_device.h>
26 #include <scsi/scsi_driver.h>
27 #include <scsi/scsi_eh.h>
28 #include <scsi/scsi_host.h>
30 #include "scsi_priv.h"
31 #include "scsi_logging.h"
34 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
35 #define SG_MEMPOOL_SIZE 2
38 * The maximum number of SG segments that we will put inside a scatterlist
39 * (unless chaining is used). Should ideally fit inside a single page, to
40 * avoid a higher order allocation.
42 #define SCSI_MAX_SG_SEGMENTS 128
44 struct scsi_host_sg_pool
{
47 struct kmem_cache
*slab
;
51 #define SP(x) { x, "sgpool-" #x }
52 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
55 #if (SCSI_MAX_SG_SEGMENTS > 16)
57 #if (SCSI_MAX_SG_SEGMENTS > 32)
59 #if (SCSI_MAX_SG_SEGMENTS > 64)
67 static void scsi_run_queue(struct request_queue
*q
);
70 * Function: scsi_unprep_request()
72 * Purpose: Remove all preparation done for a request, including its
73 * associated scsi_cmnd, so that it can be requeued.
75 * Arguments: req - request to unprepare
77 * Lock status: Assumed that no locks are held upon entry.
81 static void scsi_unprep_request(struct request
*req
)
83 struct scsi_cmnd
*cmd
= req
->special
;
85 req
->cmd_flags
&= ~REQ_DONTPREP
;
88 scsi_put_command(cmd
);
92 * Function: scsi_queue_insert()
94 * Purpose: Insert a command in the midlevel queue.
96 * Arguments: cmd - command that we are adding to queue.
97 * reason - why we are inserting command to queue.
99 * Lock status: Assumed that lock is not held upon entry.
103 * Notes: We do this for one of two cases. Either the host is busy
104 * and it cannot accept any more commands for the time being,
105 * or the device returned QUEUE_FULL and can accept no more
107 * Notes: This could be called either from an interrupt context or a
108 * normal process context.
110 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
112 struct Scsi_Host
*host
= cmd
->device
->host
;
113 struct scsi_device
*device
= cmd
->device
;
114 struct request_queue
*q
= device
->request_queue
;
118 printk("Inserting command %p into mlqueue\n", cmd
));
121 * Set the appropriate busy bit for the device/host.
123 * If the host/device isn't busy, assume that something actually
124 * completed, and that we should be able to queue a command now.
126 * Note that the prior mid-layer assumption that any host could
127 * always queue at least one command is now broken. The mid-layer
128 * will implement a user specifiable stall (see
129 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
130 * if a command is requeued with no other commands outstanding
131 * either for the device or for the host.
133 if (reason
== SCSI_MLQUEUE_HOST_BUSY
)
134 host
->host_blocked
= host
->max_host_blocked
;
135 else if (reason
== SCSI_MLQUEUE_DEVICE_BUSY
)
136 device
->device_blocked
= device
->max_device_blocked
;
139 * Decrement the counters, since these commands are no longer
140 * active on the host/device.
142 scsi_device_unbusy(device
);
145 * Requeue this command. It will go before all other commands
146 * that are already in the queue.
148 * NOTE: there is magic here about the way the queue is plugged if
149 * we have no outstanding commands.
151 * Although we *don't* plug the queue, we call the request
152 * function. The SCSI request function detects the blocked condition
153 * and plugs the queue appropriately.
155 spin_lock_irqsave(q
->queue_lock
, flags
);
156 blk_requeue_request(q
, cmd
->request
);
157 spin_unlock_irqrestore(q
->queue_lock
, flags
);
165 * scsi_execute - insert request and wait for the result
168 * @data_direction: data direction
169 * @buffer: data buffer
170 * @bufflen: len of buffer
171 * @sense: optional sense buffer
172 * @timeout: request timeout in seconds
173 * @retries: number of times to retry request
174 * @flags: or into request flags;
176 * returns the req->errors value which is the scsi_cmnd result
179 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
180 int data_direction
, void *buffer
, unsigned bufflen
,
181 unsigned char *sense
, int timeout
, int retries
, int flags
)
184 int write
= (data_direction
== DMA_TO_DEVICE
);
185 int ret
= DRIVER_ERROR
<< 24;
187 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
189 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
190 buffer
, bufflen
, __GFP_WAIT
))
193 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
194 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
197 req
->retries
= retries
;
198 req
->timeout
= timeout
;
199 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
200 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
203 * head injection *required* here otherwise quiesce won't work
205 blk_execute_rq(req
->q
, NULL
, req
, 1);
209 blk_put_request(req
);
213 EXPORT_SYMBOL(scsi_execute
);
216 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
217 int data_direction
, void *buffer
, unsigned bufflen
,
218 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
224 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
226 return DRIVER_ERROR
<< 24;
228 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
229 sense
, timeout
, retries
, 0);
231 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
236 EXPORT_SYMBOL(scsi_execute_req
);
238 struct scsi_io_context
{
240 void (*done
)(void *data
, char *sense
, int result
, int resid
);
241 char sense
[SCSI_SENSE_BUFFERSIZE
];
244 static struct kmem_cache
*scsi_io_context_cache
;
246 static void scsi_end_async(struct request
*req
, int uptodate
)
248 struct scsi_io_context
*sioc
= req
->end_io_data
;
251 sioc
->done(sioc
->data
, sioc
->sense
, req
->errors
, req
->data_len
);
253 kmem_cache_free(scsi_io_context_cache
, sioc
);
254 __blk_put_request(req
->q
, req
);
257 static int scsi_merge_bio(struct request
*rq
, struct bio
*bio
)
259 struct request_queue
*q
= rq
->q
;
261 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
262 if (rq_data_dir(rq
) == WRITE
)
263 bio
->bi_rw
|= (1 << BIO_RW
);
264 blk_queue_bounce(q
, &bio
);
266 return blk_rq_append_bio(q
, rq
, bio
);
269 static void scsi_bi_endio(struct bio
*bio
, int error
)
275 * scsi_req_map_sg - map a scatterlist into a request
276 * @rq: request to fill
278 * @nsegs: number of elements
279 * @bufflen: len of buffer
280 * @gfp: memory allocation flags
282 * scsi_req_map_sg maps a scatterlist into a request so that the
283 * request can be sent to the block layer. We do not trust the scatterlist
284 * sent to use, as some ULDs use that struct to only organize the pages.
286 static int scsi_req_map_sg(struct request
*rq
, struct scatterlist
*sgl
,
287 int nsegs
, unsigned bufflen
, gfp_t gfp
)
289 struct request_queue
*q
= rq
->q
;
290 int nr_pages
= (bufflen
+ sgl
[0].offset
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
291 unsigned int data_len
= bufflen
, len
, bytes
, off
;
292 struct scatterlist
*sg
;
294 struct bio
*bio
= NULL
;
295 int i
, err
, nr_vecs
= 0;
297 for_each_sg(sgl
, sg
, nsegs
, i
) {
303 while (len
> 0 && data_len
> 0) {
305 * sg sends a scatterlist that is larger than
306 * the data_len it wants transferred for certain
309 bytes
= min_t(unsigned int, len
, PAGE_SIZE
- off
);
310 bytes
= min(bytes
, data_len
);
313 nr_vecs
= min_t(int, BIO_MAX_PAGES
, nr_pages
);
316 bio
= bio_alloc(gfp
, nr_vecs
);
321 bio
->bi_end_io
= scsi_bi_endio
;
324 if (bio_add_pc_page(q
, bio
, page
, bytes
, off
) !=
331 if (bio
->bi_vcnt
>= nr_vecs
) {
332 err
= scsi_merge_bio(rq
, bio
);
347 rq
->buffer
= rq
->data
= NULL
;
348 rq
->data_len
= bufflen
;
352 while ((bio
= rq
->bio
) != NULL
) {
353 rq
->bio
= bio
->bi_next
;
355 * call endio instead of bio_put incase it was bounced
364 * scsi_execute_async - insert request
367 * @cmd_len: length of scsi cdb
368 * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
369 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
370 * @bufflen: len of buffer
371 * @use_sg: if buffer is a scatterlist this is the number of elements
372 * @timeout: request timeout in seconds
373 * @retries: number of times to retry request
374 * @privdata: data passed to done()
375 * @done: callback function when done
376 * @gfp: memory allocation flags
378 int scsi_execute_async(struct scsi_device
*sdev
, const unsigned char *cmd
,
379 int cmd_len
, int data_direction
, void *buffer
, unsigned bufflen
,
380 int use_sg
, int timeout
, int retries
, void *privdata
,
381 void (*done
)(void *, char *, int, int), gfp_t gfp
)
384 struct scsi_io_context
*sioc
;
386 int write
= (data_direction
== DMA_TO_DEVICE
);
388 sioc
= kmem_cache_zalloc(scsi_io_context_cache
, gfp
);
390 return DRIVER_ERROR
<< 24;
392 req
= blk_get_request(sdev
->request_queue
, write
, gfp
);
395 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
396 req
->cmd_flags
|= REQ_QUIET
;
399 err
= scsi_req_map_sg(req
, buffer
, use_sg
, bufflen
, gfp
);
401 err
= blk_rq_map_kern(req
->q
, req
, buffer
, bufflen
, gfp
);
406 req
->cmd_len
= cmd_len
;
407 memset(req
->cmd
, 0, BLK_MAX_CDB
); /* ATAPI hates garbage after CDB */
408 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
409 req
->sense
= sioc
->sense
;
411 req
->timeout
= timeout
;
412 req
->retries
= retries
;
413 req
->end_io_data
= sioc
;
415 sioc
->data
= privdata
;
418 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
422 blk_put_request(req
);
424 kmem_cache_free(scsi_io_context_cache
, sioc
);
425 return DRIVER_ERROR
<< 24;
427 EXPORT_SYMBOL_GPL(scsi_execute_async
);
430 * Function: scsi_init_cmd_errh()
432 * Purpose: Initialize cmd fields related to error handling.
434 * Arguments: cmd - command that is ready to be queued.
436 * Notes: This function has the job of initializing a number of
437 * fields related to error handling. Typically this will
438 * be called once for each command, as required.
440 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
442 cmd
->serial_number
= 0;
444 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
445 if (cmd
->cmd_len
== 0)
446 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
449 void scsi_device_unbusy(struct scsi_device
*sdev
)
451 struct Scsi_Host
*shost
= sdev
->host
;
454 spin_lock_irqsave(shost
->host_lock
, flags
);
456 if (unlikely(scsi_host_in_recovery(shost
) &&
457 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
458 scsi_eh_wakeup(shost
);
459 spin_unlock(shost
->host_lock
);
460 spin_lock(sdev
->request_queue
->queue_lock
);
462 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
466 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
467 * and call blk_run_queue for all the scsi_devices on the target -
468 * including current_sdev first.
470 * Called with *no* scsi locks held.
472 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
474 struct Scsi_Host
*shost
= current_sdev
->host
;
475 struct scsi_device
*sdev
, *tmp
;
476 struct scsi_target
*starget
= scsi_target(current_sdev
);
479 spin_lock_irqsave(shost
->host_lock
, flags
);
480 starget
->starget_sdev_user
= NULL
;
481 spin_unlock_irqrestore(shost
->host_lock
, flags
);
484 * Call blk_run_queue for all LUNs on the target, starting with
485 * current_sdev. We race with others (to set starget_sdev_user),
486 * but in most cases, we will be first. Ideally, each LU on the
487 * target would get some limited time or requests on the target.
489 blk_run_queue(current_sdev
->request_queue
);
491 spin_lock_irqsave(shost
->host_lock
, flags
);
492 if (starget
->starget_sdev_user
)
494 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
495 same_target_siblings
) {
496 if (sdev
== current_sdev
)
498 if (scsi_device_get(sdev
))
501 spin_unlock_irqrestore(shost
->host_lock
, flags
);
502 blk_run_queue(sdev
->request_queue
);
503 spin_lock_irqsave(shost
->host_lock
, flags
);
505 scsi_device_put(sdev
);
508 spin_unlock_irqrestore(shost
->host_lock
, flags
);
512 * Function: scsi_run_queue()
514 * Purpose: Select a proper request queue to serve next
516 * Arguments: q - last request's queue
520 * Notes: The previous command was completely finished, start
521 * a new one if possible.
523 static void scsi_run_queue(struct request_queue
*q
)
525 struct scsi_device
*sdev
= q
->queuedata
;
526 struct Scsi_Host
*shost
= sdev
->host
;
529 if (scsi_target(sdev
)->single_lun
)
530 scsi_single_lun_run(sdev
);
532 spin_lock_irqsave(shost
->host_lock
, flags
);
533 while (!list_empty(&shost
->starved_list
) &&
534 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
535 !((shost
->can_queue
> 0) &&
536 (shost
->host_busy
>= shost
->can_queue
))) {
538 * As long as shost is accepting commands and we have
539 * starved queues, call blk_run_queue. scsi_request_fn
540 * drops the queue_lock and can add us back to the
543 * host_lock protects the starved_list and starved_entry.
544 * scsi_request_fn must get the host_lock before checking
545 * or modifying starved_list or starved_entry.
547 sdev
= list_entry(shost
->starved_list
.next
,
548 struct scsi_device
, starved_entry
);
549 list_del_init(&sdev
->starved_entry
);
550 spin_unlock_irqrestore(shost
->host_lock
, flags
);
553 if (test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
554 !test_and_set_bit(QUEUE_FLAG_REENTER
,
555 &sdev
->request_queue
->queue_flags
)) {
556 blk_run_queue(sdev
->request_queue
);
557 clear_bit(QUEUE_FLAG_REENTER
,
558 &sdev
->request_queue
->queue_flags
);
560 blk_run_queue(sdev
->request_queue
);
562 spin_lock_irqsave(shost
->host_lock
, flags
);
563 if (unlikely(!list_empty(&sdev
->starved_entry
)))
565 * sdev lost a race, and was put back on the
566 * starved list. This is unlikely but without this
567 * in theory we could loop forever.
571 spin_unlock_irqrestore(shost
->host_lock
, flags
);
577 * Function: scsi_requeue_command()
579 * Purpose: Handle post-processing of completed commands.
581 * Arguments: q - queue to operate on
582 * cmd - command that may need to be requeued.
586 * Notes: After command completion, there may be blocks left
587 * over which weren't finished by the previous command
588 * this can be for a number of reasons - the main one is
589 * I/O errors in the middle of the request, in which case
590 * we need to request the blocks that come after the bad
592 * Notes: Upon return, cmd is a stale pointer.
594 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
596 struct request
*req
= cmd
->request
;
599 scsi_unprep_request(req
);
600 spin_lock_irqsave(q
->queue_lock
, flags
);
601 blk_requeue_request(q
, req
);
602 spin_unlock_irqrestore(q
->queue_lock
, flags
);
607 void scsi_next_command(struct scsi_cmnd
*cmd
)
609 struct scsi_device
*sdev
= cmd
->device
;
610 struct request_queue
*q
= sdev
->request_queue
;
612 /* need to hold a reference on the device before we let go of the cmd */
613 get_device(&sdev
->sdev_gendev
);
615 scsi_put_command(cmd
);
618 /* ok to remove device now */
619 put_device(&sdev
->sdev_gendev
);
622 void scsi_run_host_queues(struct Scsi_Host
*shost
)
624 struct scsi_device
*sdev
;
626 shost_for_each_device(sdev
, shost
)
627 scsi_run_queue(sdev
->request_queue
);
631 * Function: scsi_end_request()
633 * Purpose: Post-processing of completed commands (usually invoked at end
634 * of upper level post-processing and scsi_io_completion).
636 * Arguments: cmd - command that is complete.
637 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
638 * bytes - number of bytes of completed I/O
639 * requeue - indicates whether we should requeue leftovers.
641 * Lock status: Assumed that lock is not held upon entry.
643 * Returns: cmd if requeue required, NULL otherwise.
645 * Notes: This is called for block device requests in order to
646 * mark some number of sectors as complete.
648 * We are guaranteeing that the request queue will be goosed
649 * at some point during this call.
650 * Notes: If cmd was requeued, upon return it will be a stale pointer.
652 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
653 int bytes
, int requeue
)
655 struct request_queue
*q
= cmd
->device
->request_queue
;
656 struct request
*req
= cmd
->request
;
660 * If there are blocks left over at the end, set up the command
661 * to queue the remainder of them.
663 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
664 int leftover
= (req
->hard_nr_sectors
<< 9);
666 if (blk_pc_request(req
))
667 leftover
= req
->data_len
;
669 /* kill remainder if no retrys */
670 if (!uptodate
&& blk_noretry_request(req
))
671 end_that_request_chunk(req
, 0, leftover
);
675 * Bleah. Leftovers again. Stick the
676 * leftovers in the front of the
677 * queue, and goose the queue again.
679 scsi_requeue_command(q
, cmd
);
686 add_disk_randomness(req
->rq_disk
);
688 spin_lock_irqsave(q
->queue_lock
, flags
);
689 if (blk_rq_tagged(req
))
690 blk_queue_end_tag(q
, req
);
691 end_that_request_last(req
, uptodate
);
692 spin_unlock_irqrestore(q
->queue_lock
, flags
);
695 * This will goose the queue request function at the end, so we don't
696 * need to worry about launching another command.
698 scsi_next_command(cmd
);
703 * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. This limit
704 * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
706 #define SCSI_MAX_SG_CHAIN_SEGMENTS 2048
708 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
719 #if (SCSI_MAX_SG_SEGMENTS > 16)
723 #if (SCSI_MAX_SG_SEGMENTS > 32)
727 #if (SCSI_MAX_SG_SEGMENTS > 64)
735 printk(KERN_ERR
"scsi: bad segment count=%d\n", nents
);
742 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
744 struct scsi_host_sg_pool
*sgp
;
746 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
747 mempool_free(sgl
, sgp
->pool
);
750 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
752 struct scsi_host_sg_pool
*sgp
;
754 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
755 return mempool_alloc(sgp
->pool
, gfp_mask
);
758 int scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
762 BUG_ON(!cmd
->use_sg
);
764 ret
= __sg_alloc_table(&cmd
->sg_table
, cmd
->use_sg
,
765 SCSI_MAX_SG_SEGMENTS
, gfp_mask
, scsi_sg_alloc
);
767 __sg_free_table(&cmd
->sg_table
, SCSI_MAX_SG_SEGMENTS
,
770 cmd
->request_buffer
= cmd
->sg_table
.sgl
;
774 EXPORT_SYMBOL(scsi_alloc_sgtable
);
776 void scsi_free_sgtable(struct scsi_cmnd
*cmd
)
778 __sg_free_table(&cmd
->sg_table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
781 EXPORT_SYMBOL(scsi_free_sgtable
);
784 * Function: scsi_release_buffers()
786 * Purpose: Completion processing for block device I/O requests.
788 * Arguments: cmd - command that we are bailing.
790 * Lock status: Assumed that no lock is held upon entry.
794 * Notes: In the event that an upper level driver rejects a
795 * command, we must release resources allocated during
796 * the __init_io() function. Primarily this would involve
797 * the scatter-gather table, and potentially any bounce
800 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
803 scsi_free_sgtable(cmd
);
806 * Zero these out. They now point to freed memory, and it is
807 * dangerous to hang onto the pointers.
809 cmd
->request_buffer
= NULL
;
810 cmd
->request_bufflen
= 0;
814 * Function: scsi_io_completion()
816 * Purpose: Completion processing for block device I/O requests.
818 * Arguments: cmd - command that is finished.
820 * Lock status: Assumed that no lock is held upon entry.
824 * Notes: This function is matched in terms of capabilities to
825 * the function that created the scatter-gather list.
826 * In other words, if there are no bounce buffers
827 * (the normal case for most drivers), we don't need
828 * the logic to deal with cleaning up afterwards.
830 * We must do one of several things here:
832 * a) Call scsi_end_request. This will finish off the
833 * specified number of sectors. If we are done, the
834 * command block will be released, and the queue
835 * function will be goosed. If we are not done, then
836 * scsi_end_request will directly goose the queue.
838 * b) We can just use scsi_requeue_command() here. This would
839 * be used if we just wanted to retry, for example.
841 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
843 int result
= cmd
->result
;
844 int this_count
= cmd
->request_bufflen
;
845 struct request_queue
*q
= cmd
->device
->request_queue
;
846 struct request
*req
= cmd
->request
;
847 int clear_errors
= 1;
848 struct scsi_sense_hdr sshdr
;
850 int sense_deferred
= 0;
852 scsi_release_buffers(cmd
);
855 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
857 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
860 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
861 req
->errors
= result
;
864 if (sense_valid
&& req
->sense
) {
866 * SG_IO wants current and deferred errors
868 int len
= 8 + cmd
->sense_buffer
[7];
870 if (len
> SCSI_SENSE_BUFFERSIZE
)
871 len
= SCSI_SENSE_BUFFERSIZE
;
872 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
873 req
->sense_len
= len
;
876 req
->data_len
= cmd
->resid
;
880 * Next deal with any sectors which we were able to correctly
883 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
885 req
->nr_sectors
, good_bytes
));
886 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
891 /* A number of bytes were successfully read. If there
892 * are leftovers and there is some kind of error
893 * (result != 0), retry the rest.
895 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
898 /* good_bytes = 0, or (inclusive) there were leftovers and
899 * result = 0, so scsi_end_request couldn't retry.
901 if (sense_valid
&& !sense_deferred
) {
902 switch (sshdr
.sense_key
) {
904 if (cmd
->device
->removable
) {
905 /* Detected disc change. Set a bit
906 * and quietly refuse further access.
908 cmd
->device
->changed
= 1;
909 scsi_end_request(cmd
, 0, this_count
, 1);
912 /* Must have been a power glitch, or a
913 * bus reset. Could not have been a
914 * media change, so we just retry the
915 * request and see what happens.
917 scsi_requeue_command(q
, cmd
);
921 case ILLEGAL_REQUEST
:
922 /* If we had an ILLEGAL REQUEST returned, then
923 * we may have performed an unsupported
924 * command. The only thing this should be
925 * would be a ten byte read where only a six
926 * byte read was supported. Also, on a system
927 * where READ CAPACITY failed, we may have
928 * read past the end of the disk.
930 if ((cmd
->device
->use_10_for_rw
&&
931 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
932 (cmd
->cmnd
[0] == READ_10
||
933 cmd
->cmnd
[0] == WRITE_10
)) {
934 cmd
->device
->use_10_for_rw
= 0;
935 /* This will cause a retry with a
938 scsi_requeue_command(q
, cmd
);
941 scsi_end_request(cmd
, 0, this_count
, 1);
946 /* If the device is in the process of becoming
947 * ready, or has a temporary blockage, retry.
949 if (sshdr
.asc
== 0x04) {
950 switch (sshdr
.ascq
) {
951 case 0x01: /* becoming ready */
952 case 0x04: /* format in progress */
953 case 0x05: /* rebuild in progress */
954 case 0x06: /* recalculation in progress */
955 case 0x07: /* operation in progress */
956 case 0x08: /* Long write in progress */
957 case 0x09: /* self test in progress */
958 scsi_requeue_command(q
, cmd
);
964 if (!(req
->cmd_flags
& REQ_QUIET
))
965 scsi_cmd_print_sense_hdr(cmd
,
969 scsi_end_request(cmd
, 0, this_count
, 1);
971 case VOLUME_OVERFLOW
:
972 if (!(req
->cmd_flags
& REQ_QUIET
)) {
973 scmd_printk(KERN_INFO
, cmd
,
974 "Volume overflow, CDB: ");
975 __scsi_print_command(cmd
->cmnd
);
976 scsi_print_sense("", cmd
);
978 /* See SSC3rXX or current. */
979 scsi_end_request(cmd
, 0, this_count
, 1);
985 if (host_byte(result
) == DID_RESET
) {
986 /* Third party bus reset or reset for error recovery
987 * reasons. Just retry the request and see what
990 scsi_requeue_command(q
, cmd
);
994 if (!(req
->cmd_flags
& REQ_QUIET
)) {
995 scsi_print_result(cmd
);
996 if (driver_byte(result
) & DRIVER_SENSE
)
997 scsi_print_sense("", cmd
);
1000 scsi_end_request(cmd
, 0, this_count
, !result
);
1004 * Function: scsi_init_io()
1006 * Purpose: SCSI I/O initialize function.
1008 * Arguments: cmd - Command descriptor we wish to initialize
1010 * Returns: 0 on success
1011 * BLKPREP_DEFER if the failure is retryable
1013 static int scsi_init_io(struct scsi_cmnd
*cmd
)
1015 struct request
*req
= cmd
->request
;
1019 * We used to not use scatter-gather for single segment request,
1020 * but now we do (it makes highmem I/O easier to support without
1023 cmd
->use_sg
= req
->nr_phys_segments
;
1026 * If sg table allocation fails, requeue request later.
1028 if (unlikely(scsi_alloc_sgtable(cmd
, GFP_ATOMIC
))) {
1029 scsi_unprep_request(req
);
1030 return BLKPREP_DEFER
;
1034 if (blk_pc_request(req
))
1035 cmd
->request_bufflen
= req
->data_len
;
1037 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1040 * Next, walk the list, and fill in the addresses and sizes of
1043 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1044 BUG_ON(count
> cmd
->use_sg
);
1045 cmd
->use_sg
= count
;
1049 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1050 struct request
*req
)
1052 struct scsi_cmnd
*cmd
;
1054 if (!req
->special
) {
1055 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1063 /* pull a tag out of the request if we have one */
1064 cmd
->tag
= req
->tag
;
1070 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1072 struct scsi_cmnd
*cmd
;
1073 int ret
= scsi_prep_state_check(sdev
, req
);
1075 if (ret
!= BLKPREP_OK
)
1078 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1080 return BLKPREP_DEFER
;
1083 * BLOCK_PC requests may transfer data, in which case they must
1084 * a bio attached to them. Or they might contain a SCSI command
1085 * that does not transfer data, in which case they may optionally
1086 * submit a request without an attached bio.
1091 BUG_ON(!req
->nr_phys_segments
);
1093 ret
= scsi_init_io(cmd
);
1097 BUG_ON(req
->data_len
);
1100 cmd
->request_bufflen
= 0;
1101 cmd
->request_buffer
= NULL
;
1106 BUILD_BUG_ON(sizeof(req
->cmd
) > sizeof(cmd
->cmnd
));
1107 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1108 cmd
->cmd_len
= req
->cmd_len
;
1110 cmd
->sc_data_direction
= DMA_NONE
;
1111 else if (rq_data_dir(req
) == WRITE
)
1112 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1114 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1116 cmd
->transfersize
= req
->data_len
;
1117 cmd
->allowed
= req
->retries
;
1118 cmd
->timeout_per_command
= req
->timeout
;
1121 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1124 * Setup a REQ_TYPE_FS command. These are simple read/write request
1125 * from filesystems that still need to be translated to SCSI CDBs from
1128 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1130 struct scsi_cmnd
*cmd
;
1131 int ret
= scsi_prep_state_check(sdev
, req
);
1133 if (ret
!= BLKPREP_OK
)
1136 * Filesystem requests must transfer data.
1138 BUG_ON(!req
->nr_phys_segments
);
1140 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1142 return BLKPREP_DEFER
;
1144 return scsi_init_io(cmd
);
1146 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1148 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1150 int ret
= BLKPREP_OK
;
1153 * If the device is not in running state we will reject some
1156 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1157 switch (sdev
->sdev_state
) {
1160 * If the device is offline we refuse to process any
1161 * commands. The device must be brought online
1162 * before trying any recovery commands.
1164 sdev_printk(KERN_ERR
, sdev
,
1165 "rejecting I/O to offline device\n");
1170 * If the device is fully deleted, we refuse to
1171 * process any commands as well.
1173 sdev_printk(KERN_ERR
, sdev
,
1174 "rejecting I/O to dead device\n");
1180 * If the devices is blocked we defer normal commands.
1182 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1183 ret
= BLKPREP_DEFER
;
1187 * For any other not fully online state we only allow
1188 * special commands. In particular any user initiated
1189 * command is not allowed.
1191 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1198 EXPORT_SYMBOL(scsi_prep_state_check
);
1200 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1202 struct scsi_device
*sdev
= q
->queuedata
;
1206 req
->errors
= DID_NO_CONNECT
<< 16;
1207 /* release the command and kill it */
1209 struct scsi_cmnd
*cmd
= req
->special
;
1210 scsi_release_buffers(cmd
);
1211 scsi_put_command(cmd
);
1212 req
->special
= NULL
;
1217 * If we defer, the elv_next_request() returns NULL, but the
1218 * queue must be restarted, so we plug here if no returning
1219 * command will automatically do that.
1221 if (sdev
->device_busy
== 0)
1225 req
->cmd_flags
|= REQ_DONTPREP
;
1230 EXPORT_SYMBOL(scsi_prep_return
);
1232 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1234 struct scsi_device
*sdev
= q
->queuedata
;
1235 int ret
= BLKPREP_KILL
;
1237 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1238 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1239 return scsi_prep_return(q
, req
, ret
);
1243 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1246 * Called with the queue_lock held.
1248 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1249 struct scsi_device
*sdev
)
1251 if (sdev
->device_busy
>= sdev
->queue_depth
)
1253 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1255 * unblock after device_blocked iterates to zero
1257 if (--sdev
->device_blocked
== 0) {
1259 sdev_printk(KERN_INFO
, sdev
,
1260 "unblocking device at zero depth\n"));
1266 if (sdev
->device_blocked
)
1273 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1274 * return 0. We must end up running the queue again whenever 0 is
1275 * returned, else IO can hang.
1277 * Called with host_lock held.
1279 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1280 struct Scsi_Host
*shost
,
1281 struct scsi_device
*sdev
)
1283 if (scsi_host_in_recovery(shost
))
1285 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1287 * unblock after host_blocked iterates to zero
1289 if (--shost
->host_blocked
== 0) {
1291 printk("scsi%d unblocking host at zero depth\n",
1298 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1299 shost
->host_blocked
|| shost
->host_self_blocked
) {
1300 if (list_empty(&sdev
->starved_entry
))
1301 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1305 /* We're OK to process the command, so we can't be starved */
1306 if (!list_empty(&sdev
->starved_entry
))
1307 list_del_init(&sdev
->starved_entry
);
1313 * Kill a request for a dead device
1315 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1317 struct scsi_cmnd
*cmd
= req
->special
;
1318 struct scsi_device
*sdev
= cmd
->device
;
1319 struct Scsi_Host
*shost
= sdev
->host
;
1321 blkdev_dequeue_request(req
);
1323 if (unlikely(cmd
== NULL
)) {
1324 printk(KERN_CRIT
"impossible request in %s.\n",
1329 scsi_init_cmd_errh(cmd
);
1330 cmd
->result
= DID_NO_CONNECT
<< 16;
1331 atomic_inc(&cmd
->device
->iorequest_cnt
);
1334 * SCSI request completion path will do scsi_device_unbusy(),
1335 * bump busy counts. To bump the counters, we need to dance
1336 * with the locks as normal issue path does.
1338 sdev
->device_busy
++;
1339 spin_unlock(sdev
->request_queue
->queue_lock
);
1340 spin_lock(shost
->host_lock
);
1342 spin_unlock(shost
->host_lock
);
1343 spin_lock(sdev
->request_queue
->queue_lock
);
1348 static void scsi_softirq_done(struct request
*rq
)
1350 struct scsi_cmnd
*cmd
= rq
->completion_data
;
1351 unsigned long wait_for
= (cmd
->allowed
+ 1) * cmd
->timeout_per_command
;
1354 INIT_LIST_HEAD(&cmd
->eh_entry
);
1356 disposition
= scsi_decide_disposition(cmd
);
1357 if (disposition
!= SUCCESS
&&
1358 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1359 sdev_printk(KERN_ERR
, cmd
->device
,
1360 "timing out command, waited %lus\n",
1362 disposition
= SUCCESS
;
1365 scsi_log_completion(cmd
, disposition
);
1367 switch (disposition
) {
1369 scsi_finish_command(cmd
);
1372 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1374 case ADD_TO_MLQUEUE
:
1375 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1378 if (!scsi_eh_scmd_add(cmd
, 0))
1379 scsi_finish_command(cmd
);
1384 * Function: scsi_request_fn()
1386 * Purpose: Main strategy routine for SCSI.
1388 * Arguments: q - Pointer to actual queue.
1392 * Lock status: IO request lock assumed to be held when called.
1394 static void scsi_request_fn(struct request_queue
*q
)
1396 struct scsi_device
*sdev
= q
->queuedata
;
1397 struct Scsi_Host
*shost
;
1398 struct scsi_cmnd
*cmd
;
1399 struct request
*req
;
1402 printk("scsi: killing requests for dead queue\n");
1403 while ((req
= elv_next_request(q
)) != NULL
)
1404 scsi_kill_request(req
, q
);
1408 if(!get_device(&sdev
->sdev_gendev
))
1409 /* We must be tearing the block queue down already */
1413 * To start with, we keep looping until the queue is empty, or until
1414 * the host is no longer able to accept any more requests.
1417 while (!blk_queue_plugged(q
)) {
1420 * get next queueable request. We do this early to make sure
1421 * that the request is fully prepared even if we cannot
1424 req
= elv_next_request(q
);
1425 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1428 if (unlikely(!scsi_device_online(sdev
))) {
1429 sdev_printk(KERN_ERR
, sdev
,
1430 "rejecting I/O to offline device\n");
1431 scsi_kill_request(req
, q
);
1437 * Remove the request from the request list.
1439 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1440 blkdev_dequeue_request(req
);
1441 sdev
->device_busy
++;
1443 spin_unlock(q
->queue_lock
);
1445 if (unlikely(cmd
== NULL
)) {
1446 printk(KERN_CRIT
"impossible request in %s.\n"
1447 "please mail a stack trace to "
1448 "linux-scsi@vger.kernel.org\n",
1450 blk_dump_rq_flags(req
, "foo");
1453 spin_lock(shost
->host_lock
);
1455 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1457 if (scsi_target(sdev
)->single_lun
) {
1458 if (scsi_target(sdev
)->starget_sdev_user
&&
1459 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1461 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1466 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1467 * take the lock again.
1469 spin_unlock_irq(shost
->host_lock
);
1472 * Finally, initialize any error handling parameters, and set up
1473 * the timers for timeouts.
1475 scsi_init_cmd_errh(cmd
);
1478 * Dispatch the command to the low-level driver.
1480 rtn
= scsi_dispatch_cmd(cmd
);
1481 spin_lock_irq(q
->queue_lock
);
1483 /* we're refusing the command; because of
1484 * the way locks get dropped, we need to
1485 * check here if plugging is required */
1486 if(sdev
->device_busy
== 0)
1496 spin_unlock_irq(shost
->host_lock
);
1499 * lock q, handle tag, requeue req, and decrement device_busy. We
1500 * must return with queue_lock held.
1502 * Decrementing device_busy without checking it is OK, as all such
1503 * cases (host limits or settings) should run the queue at some
1506 spin_lock_irq(q
->queue_lock
);
1507 blk_requeue_request(q
, req
);
1508 sdev
->device_busy
--;
1509 if(sdev
->device_busy
== 0)
1512 /* must be careful here...if we trigger the ->remove() function
1513 * we cannot be holding the q lock */
1514 spin_unlock_irq(q
->queue_lock
);
1515 put_device(&sdev
->sdev_gendev
);
1516 spin_lock_irq(q
->queue_lock
);
1519 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1521 struct device
*host_dev
;
1522 u64 bounce_limit
= 0xffffffff;
1524 if (shost
->unchecked_isa_dma
)
1525 return BLK_BOUNCE_ISA
;
1527 * Platforms with virtual-DMA translation
1528 * hardware have no practical limit.
1530 if (!PCI_DMA_BUS_IS_PHYS
)
1531 return BLK_BOUNCE_ANY
;
1533 host_dev
= scsi_get_device(shost
);
1534 if (host_dev
&& host_dev
->dma_mask
)
1535 bounce_limit
= *host_dev
->dma_mask
;
1537 return bounce_limit
;
1539 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1541 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1542 request_fn_proc
*request_fn
)
1544 struct request_queue
*q
;
1546 q
= blk_init_queue(request_fn
, NULL
);
1551 * this limit is imposed by hardware restrictions
1553 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1556 * In the future, sg chaining support will be mandatory and this
1557 * ifdef can then go away. Right now we don't have all archs
1558 * converted, so better keep it safe.
1560 #ifdef ARCH_HAS_SG_CHAIN
1561 if (shost
->use_sg_chaining
)
1562 blk_queue_max_phys_segments(q
, SCSI_MAX_SG_CHAIN_SEGMENTS
);
1564 blk_queue_max_phys_segments(q
, SCSI_MAX_SG_SEGMENTS
);
1566 blk_queue_max_phys_segments(q
, SCSI_MAX_SG_SEGMENTS
);
1569 blk_queue_max_sectors(q
, shost
->max_sectors
);
1570 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1571 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1573 if (!shost
->use_clustering
)
1574 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1577 * set a reasonable default alignment on word boundaries: the
1578 * host and device may alter it using
1579 * blk_queue_update_dma_alignment() later.
1581 blk_queue_dma_alignment(q
, 0x03);
1585 EXPORT_SYMBOL(__scsi_alloc_queue
);
1587 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1589 struct request_queue
*q
;
1591 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1595 blk_queue_prep_rq(q
, scsi_prep_fn
);
1596 blk_queue_softirq_done(q
, scsi_softirq_done
);
1600 void scsi_free_queue(struct request_queue
*q
)
1602 blk_cleanup_queue(q
);
1606 * Function: scsi_block_requests()
1608 * Purpose: Utility function used by low-level drivers to prevent further
1609 * commands from being queued to the device.
1611 * Arguments: shost - Host in question
1615 * Lock status: No locks are assumed held.
1617 * Notes: There is no timer nor any other means by which the requests
1618 * get unblocked other than the low-level driver calling
1619 * scsi_unblock_requests().
1621 void scsi_block_requests(struct Scsi_Host
*shost
)
1623 shost
->host_self_blocked
= 1;
1625 EXPORT_SYMBOL(scsi_block_requests
);
1628 * Function: scsi_unblock_requests()
1630 * Purpose: Utility function used by low-level drivers to allow further
1631 * commands from being queued to the device.
1633 * Arguments: shost - Host in question
1637 * Lock status: No locks are assumed held.
1639 * Notes: There is no timer nor any other means by which the requests
1640 * get unblocked other than the low-level driver calling
1641 * scsi_unblock_requests().
1643 * This is done as an API function so that changes to the
1644 * internals of the scsi mid-layer won't require wholesale
1645 * changes to drivers that use this feature.
1647 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1649 shost
->host_self_blocked
= 0;
1650 scsi_run_host_queues(shost
);
1652 EXPORT_SYMBOL(scsi_unblock_requests
);
1654 int __init
scsi_init_queue(void)
1658 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1659 sizeof(struct scsi_io_context
),
1661 if (!scsi_io_context_cache
) {
1662 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1666 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1667 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1668 int size
= sgp
->size
* sizeof(struct scatterlist
);
1670 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1671 SLAB_HWCACHE_ALIGN
, NULL
);
1673 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1677 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1680 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1688 void scsi_exit_queue(void)
1692 kmem_cache_destroy(scsi_io_context_cache
);
1694 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1695 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1696 mempool_destroy(sgp
->pool
);
1697 kmem_cache_destroy(sgp
->slab
);
1702 * scsi_mode_select - issue a mode select
1703 * @sdev: SCSI device to be queried
1704 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1705 * @sp: Save page bit (0 == don't save, 1 == save)
1706 * @modepage: mode page being requested
1707 * @buffer: request buffer (may not be smaller than eight bytes)
1708 * @len: length of request buffer.
1709 * @timeout: command timeout
1710 * @retries: number of retries before failing
1711 * @data: returns a structure abstracting the mode header data
1712 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1713 * must be SCSI_SENSE_BUFFERSIZE big.
1715 * Returns zero if successful; negative error number or scsi
1720 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1721 unsigned char *buffer
, int len
, int timeout
, int retries
,
1722 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1724 unsigned char cmd
[10];
1725 unsigned char *real_buffer
;
1728 memset(cmd
, 0, sizeof(cmd
));
1729 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1731 if (sdev
->use_10_for_ms
) {
1734 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1737 memcpy(real_buffer
+ 8, buffer
, len
);
1741 real_buffer
[2] = data
->medium_type
;
1742 real_buffer
[3] = data
->device_specific
;
1743 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1745 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1746 real_buffer
[7] = data
->block_descriptor_length
;
1748 cmd
[0] = MODE_SELECT_10
;
1752 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1756 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1759 memcpy(real_buffer
+ 4, buffer
, len
);
1762 real_buffer
[1] = data
->medium_type
;
1763 real_buffer
[2] = data
->device_specific
;
1764 real_buffer
[3] = data
->block_descriptor_length
;
1767 cmd
[0] = MODE_SELECT
;
1771 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1772 sshdr
, timeout
, retries
);
1776 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1779 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1780 * @sdev: SCSI device to be queried
1781 * @dbd: set if mode sense will allow block descriptors to be returned
1782 * @modepage: mode page being requested
1783 * @buffer: request buffer (may not be smaller than eight bytes)
1784 * @len: length of request buffer.
1785 * @timeout: command timeout
1786 * @retries: number of retries before failing
1787 * @data: returns a structure abstracting the mode header data
1788 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1789 * must be SCSI_SENSE_BUFFERSIZE big.
1791 * Returns zero if unsuccessful, or the header offset (either 4
1792 * or 8 depending on whether a six or ten byte command was
1793 * issued) if successful.
1796 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1797 unsigned char *buffer
, int len
, int timeout
, int retries
,
1798 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1800 unsigned char cmd
[12];
1804 struct scsi_sense_hdr my_sshdr
;
1806 memset(data
, 0, sizeof(*data
));
1807 memset(&cmd
[0], 0, 12);
1808 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1811 /* caller might not be interested in sense, but we need it */
1816 use_10_for_ms
= sdev
->use_10_for_ms
;
1818 if (use_10_for_ms
) {
1822 cmd
[0] = MODE_SENSE_10
;
1829 cmd
[0] = MODE_SENSE
;
1834 memset(buffer
, 0, len
);
1836 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1837 sshdr
, timeout
, retries
);
1839 /* This code looks awful: what it's doing is making sure an
1840 * ILLEGAL REQUEST sense return identifies the actual command
1841 * byte as the problem. MODE_SENSE commands can return
1842 * ILLEGAL REQUEST if the code page isn't supported */
1844 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1845 (driver_byte(result
) & DRIVER_SENSE
)) {
1846 if (scsi_sense_valid(sshdr
)) {
1847 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1848 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1850 * Invalid command operation code
1852 sdev
->use_10_for_ms
= 0;
1858 if(scsi_status_is_good(result
)) {
1859 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1860 (modepage
== 6 || modepage
== 8))) {
1861 /* Initio breakage? */
1864 data
->medium_type
= 0;
1865 data
->device_specific
= 0;
1867 data
->block_descriptor_length
= 0;
1868 } else if(use_10_for_ms
) {
1869 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1870 data
->medium_type
= buffer
[2];
1871 data
->device_specific
= buffer
[3];
1872 data
->longlba
= buffer
[4] & 0x01;
1873 data
->block_descriptor_length
= buffer
[6]*256
1876 data
->length
= buffer
[0] + 1;
1877 data
->medium_type
= buffer
[1];
1878 data
->device_specific
= buffer
[2];
1879 data
->block_descriptor_length
= buffer
[3];
1881 data
->header_length
= header_length
;
1886 EXPORT_SYMBOL(scsi_mode_sense
);
1889 * scsi_test_unit_ready - test if unit is ready
1890 * @sdev: scsi device to change the state of.
1891 * @timeout: command timeout
1892 * @retries: number of retries before failing
1893 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1894 * returning sense. Make sure that this is cleared before passing
1897 * Returns zero if unsuccessful or an error if TUR failed. For
1898 * removable media, a return of NOT_READY or UNIT_ATTENTION is
1899 * translated to success, with the ->changed flag updated.
1902 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
1903 struct scsi_sense_hdr
*sshdr_external
)
1906 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1908 struct scsi_sense_hdr
*sshdr
;
1911 if (!sshdr_external
)
1912 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
1914 sshdr
= sshdr_external
;
1916 /* try to eat the UNIT_ATTENTION if there are enough retries */
1918 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
1920 } while ((driver_byte(result
) & DRIVER_SENSE
) &&
1921 sshdr
&& sshdr
->sense_key
== UNIT_ATTENTION
&&
1925 /* could not allocate sense buffer, so can't process it */
1928 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1930 if ((scsi_sense_valid(sshdr
)) &&
1931 ((sshdr
->sense_key
== UNIT_ATTENTION
) ||
1932 (sshdr
->sense_key
== NOT_READY
))) {
1937 if (!sshdr_external
)
1941 EXPORT_SYMBOL(scsi_test_unit_ready
);
1944 * scsi_device_set_state - Take the given device through the device state model.
1945 * @sdev: scsi device to change the state of.
1946 * @state: state to change to.
1948 * Returns zero if unsuccessful or an error if the requested
1949 * transition is illegal.
1952 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1954 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1956 if (state
== oldstate
)
1961 /* There are no legal states that come back to
1962 * created. This is the manually initialised start
2036 sdev
->sdev_state
= state
;
2040 SCSI_LOG_ERROR_RECOVERY(1,
2041 sdev_printk(KERN_ERR
, sdev
,
2042 "Illegal state transition %s->%s\n",
2043 scsi_device_state_name(oldstate
),
2044 scsi_device_state_name(state
))
2048 EXPORT_SYMBOL(scsi_device_set_state
);
2051 * sdev_evt_emit - emit a single SCSI device uevent
2052 * @sdev: associated SCSI device
2053 * @evt: event to emit
2055 * Send a single uevent (scsi_event) to the associated scsi_device.
2057 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2062 switch (evt
->evt_type
) {
2063 case SDEV_EVT_MEDIA_CHANGE
:
2064 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2074 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2078 * sdev_evt_thread - send a uevent for each scsi event
2079 * @work: work struct for scsi_device
2081 * Dispatch queued events to their associated scsi_device kobjects
2084 void scsi_evt_thread(struct work_struct
*work
)
2086 struct scsi_device
*sdev
;
2087 LIST_HEAD(event_list
);
2089 sdev
= container_of(work
, struct scsi_device
, event_work
);
2092 struct scsi_event
*evt
;
2093 struct list_head
*this, *tmp
;
2094 unsigned long flags
;
2096 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2097 list_splice_init(&sdev
->event_list
, &event_list
);
2098 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2100 if (list_empty(&event_list
))
2103 list_for_each_safe(this, tmp
, &event_list
) {
2104 evt
= list_entry(this, struct scsi_event
, node
);
2105 list_del(&evt
->node
);
2106 scsi_evt_emit(sdev
, evt
);
2113 * sdev_evt_send - send asserted event to uevent thread
2114 * @sdev: scsi_device event occurred on
2115 * @evt: event to send
2117 * Assert scsi device event asynchronously.
2119 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2121 unsigned long flags
;
2123 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2128 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2129 list_add_tail(&evt
->node
, &sdev
->event_list
);
2130 schedule_work(&sdev
->event_work
);
2131 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2133 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2136 * sdev_evt_alloc - allocate a new scsi event
2137 * @evt_type: type of event to allocate
2138 * @gfpflags: GFP flags for allocation
2140 * Allocates and returns a new scsi_event.
2142 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2145 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2149 evt
->evt_type
= evt_type
;
2150 INIT_LIST_HEAD(&evt
->node
);
2152 /* evt_type-specific initialization, if any */
2154 case SDEV_EVT_MEDIA_CHANGE
:
2162 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2165 * sdev_evt_send_simple - send asserted event to uevent thread
2166 * @sdev: scsi_device event occurred on
2167 * @evt_type: type of event to send
2168 * @gfpflags: GFP flags for allocation
2170 * Assert scsi device event asynchronously, given an event type.
2172 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2173 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2175 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2177 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2182 sdev_evt_send(sdev
, evt
);
2184 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2187 * scsi_device_quiesce - Block user issued commands.
2188 * @sdev: scsi device to quiesce.
2190 * This works by trying to transition to the SDEV_QUIESCE state
2191 * (which must be a legal transition). When the device is in this
2192 * state, only special requests will be accepted, all others will
2193 * be deferred. Since special requests may also be requeued requests,
2194 * a successful return doesn't guarantee the device will be
2195 * totally quiescent.
2197 * Must be called with user context, may sleep.
2199 * Returns zero if unsuccessful or an error if not.
2202 scsi_device_quiesce(struct scsi_device
*sdev
)
2204 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2208 scsi_run_queue(sdev
->request_queue
);
2209 while (sdev
->device_busy
) {
2210 msleep_interruptible(200);
2211 scsi_run_queue(sdev
->request_queue
);
2215 EXPORT_SYMBOL(scsi_device_quiesce
);
2218 * scsi_device_resume - Restart user issued commands to a quiesced device.
2219 * @sdev: scsi device to resume.
2221 * Moves the device from quiesced back to running and restarts the
2224 * Must be called with user context, may sleep.
2227 scsi_device_resume(struct scsi_device
*sdev
)
2229 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2231 scsi_run_queue(sdev
->request_queue
);
2233 EXPORT_SYMBOL(scsi_device_resume
);
2236 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2238 scsi_device_quiesce(sdev
);
2242 scsi_target_quiesce(struct scsi_target
*starget
)
2244 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2246 EXPORT_SYMBOL(scsi_target_quiesce
);
2249 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2251 scsi_device_resume(sdev
);
2255 scsi_target_resume(struct scsi_target
*starget
)
2257 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2259 EXPORT_SYMBOL(scsi_target_resume
);
2262 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2263 * @sdev: device to block
2265 * Block request made by scsi lld's to temporarily stop all
2266 * scsi commands on the specified device. Called from interrupt
2267 * or normal process context.
2269 * Returns zero if successful or error if not
2272 * This routine transitions the device to the SDEV_BLOCK state
2273 * (which must be a legal transition). When the device is in this
2274 * state, all commands are deferred until the scsi lld reenables
2275 * the device with scsi_device_unblock or device_block_tmo fires.
2276 * This routine assumes the host_lock is held on entry.
2279 scsi_internal_device_block(struct scsi_device
*sdev
)
2281 struct request_queue
*q
= sdev
->request_queue
;
2282 unsigned long flags
;
2285 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2290 * The device has transitioned to SDEV_BLOCK. Stop the
2291 * block layer from calling the midlayer with this device's
2294 spin_lock_irqsave(q
->queue_lock
, flags
);
2296 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2300 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2303 * scsi_internal_device_unblock - resume a device after a block request
2304 * @sdev: device to resume
2306 * Called by scsi lld's or the midlayer to restart the device queue
2307 * for the previously suspended scsi device. Called from interrupt or
2308 * normal process context.
2310 * Returns zero if successful or error if not.
2313 * This routine transitions the device to the SDEV_RUNNING state
2314 * (which must be a legal transition) allowing the midlayer to
2315 * goose the queue for this device. This routine assumes the
2316 * host_lock is held upon entry.
2319 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2321 struct request_queue
*q
= sdev
->request_queue
;
2323 unsigned long flags
;
2326 * Try to transition the scsi device to SDEV_RUNNING
2327 * and goose the device queue if successful.
2329 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2333 spin_lock_irqsave(q
->queue_lock
, flags
);
2335 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2339 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2342 device_block(struct scsi_device
*sdev
, void *data
)
2344 scsi_internal_device_block(sdev
);
2348 target_block(struct device
*dev
, void *data
)
2350 if (scsi_is_target_device(dev
))
2351 starget_for_each_device(to_scsi_target(dev
), NULL
,
2357 scsi_target_block(struct device
*dev
)
2359 if (scsi_is_target_device(dev
))
2360 starget_for_each_device(to_scsi_target(dev
), NULL
,
2363 device_for_each_child(dev
, NULL
, target_block
);
2365 EXPORT_SYMBOL_GPL(scsi_target_block
);
2368 device_unblock(struct scsi_device
*sdev
, void *data
)
2370 scsi_internal_device_unblock(sdev
);
2374 target_unblock(struct device
*dev
, void *data
)
2376 if (scsi_is_target_device(dev
))
2377 starget_for_each_device(to_scsi_target(dev
), NULL
,
2383 scsi_target_unblock(struct device
*dev
)
2385 if (scsi_is_target_device(dev
))
2386 starget_for_each_device(to_scsi_target(dev
), NULL
,
2389 device_for_each_child(dev
, NULL
, target_unblock
);
2391 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2394 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2395 * @sgl: scatter-gather list
2396 * @sg_count: number of segments in sg
2397 * @offset: offset in bytes into sg, on return offset into the mapped area
2398 * @len: bytes to map, on return number of bytes mapped
2400 * Returns virtual address of the start of the mapped page
2402 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2403 size_t *offset
, size_t *len
)
2406 size_t sg_len
= 0, len_complete
= 0;
2407 struct scatterlist
*sg
;
2410 WARN_ON(!irqs_disabled());
2412 for_each_sg(sgl
, sg
, sg_count
, i
) {
2413 len_complete
= sg_len
; /* Complete sg-entries */
2414 sg_len
+= sg
->length
;
2415 if (sg_len
> *offset
)
2419 if (unlikely(i
== sg_count
)) {
2420 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2422 __FUNCTION__
, sg_len
, *offset
, sg_count
);
2427 /* Offset starting from the beginning of first page in this sg-entry */
2428 *offset
= *offset
- len_complete
+ sg
->offset
;
2430 /* Assumption: contiguous pages can be accessed as "page + i" */
2431 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2432 *offset
&= ~PAGE_MASK
;
2434 /* Bytes in this sg-entry from *offset to the end of the page */
2435 sg_len
= PAGE_SIZE
- *offset
;
2439 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2441 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2444 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2445 * @virt: virtual address to be unmapped
2447 void scsi_kunmap_atomic_sg(void *virt
)
2449 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2451 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);