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>
21 #include <scsi/scsi.h>
22 #include <scsi/scsi_cmnd.h>
23 #include <scsi/scsi_dbg.h>
24 #include <scsi/scsi_device.h>
25 #include <scsi/scsi_driver.h>
26 #include <scsi/scsi_eh.h>
27 #include <scsi/scsi_host.h>
29 #include "scsi_priv.h"
30 #include "scsi_logging.h"
33 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
34 #define SG_MEMPOOL_SIZE 32
36 struct scsi_host_sg_pool
{
43 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
44 #error SCSI_MAX_PHYS_SEGMENTS is too small
47 #define SP(x) { x, "sgpool-" #x }
48 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
52 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
54 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
56 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
58 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
59 #error SCSI_MAX_PHYS_SEGMENTS is too large
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 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 kmem_cache_t
*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
);
267 blk_rq_bio_prep(q
, rq
, bio
);
268 else if (!q
->back_merge_fn(q
, rq
, bio
))
271 rq
->biotail
->bi_next
= bio
;
273 rq
->hard_nr_sectors
+= bio_sectors(bio
);
274 rq
->nr_sectors
= rq
->hard_nr_sectors
;
280 static int scsi_bi_endio(struct bio
*bio
, unsigned int bytes_done
, int error
)
290 * scsi_req_map_sg - map a scatterlist into a request
291 * @rq: request to fill
293 * @nsegs: number of elements
294 * @bufflen: len of buffer
295 * @gfp: memory allocation flags
297 * scsi_req_map_sg maps a scatterlist into a request so that the
298 * request can be sent to the block layer. We do not trust the scatterlist
299 * sent to use, as some ULDs use that struct to only organize the pages.
301 static int scsi_req_map_sg(struct request
*rq
, struct scatterlist
*sgl
,
302 int nsegs
, unsigned bufflen
, gfp_t gfp
)
304 struct request_queue
*q
= rq
->q
;
305 int nr_pages
= (bufflen
+ sgl
[0].offset
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
306 unsigned int data_len
= 0, len
, bytes
, off
;
308 struct bio
*bio
= NULL
;
309 int i
, err
, nr_vecs
= 0;
311 for (i
= 0; i
< nsegs
; i
++) {
318 bytes
= min_t(unsigned int, len
, PAGE_SIZE
- off
);
321 nr_vecs
= min_t(int, BIO_MAX_PAGES
, nr_pages
);
324 bio
= bio_alloc(gfp
, nr_vecs
);
329 bio
->bi_end_io
= scsi_bi_endio
;
332 if (bio_add_pc_page(q
, bio
, page
, bytes
, off
) !=
339 if (bio
->bi_vcnt
>= nr_vecs
) {
340 err
= scsi_merge_bio(rq
, bio
);
342 bio_endio(bio
, bio
->bi_size
, 0);
354 rq
->buffer
= rq
->data
= NULL
;
355 rq
->data_len
= data_len
;
359 while ((bio
= rq
->bio
) != NULL
) {
360 rq
->bio
= bio
->bi_next
;
362 * call endio instead of bio_put incase it was bounced
364 bio_endio(bio
, bio
->bi_size
, 0);
371 * scsi_execute_async - insert request
374 * @cmd_len: length of scsi cdb
375 * @data_direction: data direction
376 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
377 * @bufflen: len of buffer
378 * @use_sg: if buffer is a scatterlist this is the number of elements
379 * @timeout: request timeout in seconds
380 * @retries: number of times to retry request
381 * @flags: or into request flags
383 int scsi_execute_async(struct scsi_device
*sdev
, const unsigned char *cmd
,
384 int cmd_len
, int data_direction
, void *buffer
, unsigned bufflen
,
385 int use_sg
, int timeout
, int retries
, void *privdata
,
386 void (*done
)(void *, char *, int, int), gfp_t gfp
)
389 struct scsi_io_context
*sioc
;
391 int write
= (data_direction
== DMA_TO_DEVICE
);
393 sioc
= kmem_cache_alloc(scsi_io_context_cache
, gfp
);
395 return DRIVER_ERROR
<< 24;
396 memset(sioc
, 0, sizeof(*sioc
));
398 req
= blk_get_request(sdev
->request_queue
, write
, gfp
);
401 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
402 req
->cmd_flags
|= REQ_QUIET
;
405 err
= scsi_req_map_sg(req
, buffer
, use_sg
, bufflen
, gfp
);
407 err
= blk_rq_map_kern(req
->q
, req
, buffer
, bufflen
, gfp
);
412 req
->cmd_len
= cmd_len
;
413 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
414 req
->sense
= sioc
->sense
;
416 req
->timeout
= timeout
;
417 req
->retries
= retries
;
418 req
->end_io_data
= sioc
;
420 sioc
->data
= privdata
;
423 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
427 blk_put_request(req
);
429 kmem_cache_free(scsi_io_context_cache
, sioc
);
430 return DRIVER_ERROR
<< 24;
432 EXPORT_SYMBOL_GPL(scsi_execute_async
);
435 * Function: scsi_init_cmd_errh()
437 * Purpose: Initialize cmd fields related to error handling.
439 * Arguments: cmd - command that is ready to be queued.
441 * Notes: This function has the job of initializing a number of
442 * fields related to error handling. Typically this will
443 * be called once for each command, as required.
445 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
447 cmd
->serial_number
= 0;
448 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
449 if (cmd
->cmd_len
== 0)
450 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
453 void scsi_device_unbusy(struct scsi_device
*sdev
)
455 struct Scsi_Host
*shost
= sdev
->host
;
458 spin_lock_irqsave(shost
->host_lock
, flags
);
460 if (unlikely(scsi_host_in_recovery(shost
) &&
461 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
462 scsi_eh_wakeup(shost
);
463 spin_unlock(shost
->host_lock
);
464 spin_lock(sdev
->request_queue
->queue_lock
);
466 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
470 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
471 * and call blk_run_queue for all the scsi_devices on the target -
472 * including current_sdev first.
474 * Called with *no* scsi locks held.
476 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
478 struct Scsi_Host
*shost
= current_sdev
->host
;
479 struct scsi_device
*sdev
, *tmp
;
480 struct scsi_target
*starget
= scsi_target(current_sdev
);
483 spin_lock_irqsave(shost
->host_lock
, flags
);
484 starget
->starget_sdev_user
= NULL
;
485 spin_unlock_irqrestore(shost
->host_lock
, flags
);
488 * Call blk_run_queue for all LUNs on the target, starting with
489 * current_sdev. We race with others (to set starget_sdev_user),
490 * but in most cases, we will be first. Ideally, each LU on the
491 * target would get some limited time or requests on the target.
493 blk_run_queue(current_sdev
->request_queue
);
495 spin_lock_irqsave(shost
->host_lock
, flags
);
496 if (starget
->starget_sdev_user
)
498 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
499 same_target_siblings
) {
500 if (sdev
== current_sdev
)
502 if (scsi_device_get(sdev
))
505 spin_unlock_irqrestore(shost
->host_lock
, flags
);
506 blk_run_queue(sdev
->request_queue
);
507 spin_lock_irqsave(shost
->host_lock
, flags
);
509 scsi_device_put(sdev
);
512 spin_unlock_irqrestore(shost
->host_lock
, flags
);
516 * Function: scsi_run_queue()
518 * Purpose: Select a proper request queue to serve next
520 * Arguments: q - last request's queue
524 * Notes: The previous command was completely finished, start
525 * a new one if possible.
527 static void scsi_run_queue(struct request_queue
*q
)
529 struct scsi_device
*sdev
= q
->queuedata
;
530 struct Scsi_Host
*shost
= sdev
->host
;
533 if (sdev
->single_lun
)
534 scsi_single_lun_run(sdev
);
536 spin_lock_irqsave(shost
->host_lock
, flags
);
537 while (!list_empty(&shost
->starved_list
) &&
538 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
539 !((shost
->can_queue
> 0) &&
540 (shost
->host_busy
>= shost
->can_queue
))) {
542 * As long as shost is accepting commands and we have
543 * starved queues, call blk_run_queue. scsi_request_fn
544 * drops the queue_lock and can add us back to the
547 * host_lock protects the starved_list and starved_entry.
548 * scsi_request_fn must get the host_lock before checking
549 * or modifying starved_list or starved_entry.
551 sdev
= list_entry(shost
->starved_list
.next
,
552 struct scsi_device
, starved_entry
);
553 list_del_init(&sdev
->starved_entry
);
554 spin_unlock_irqrestore(shost
->host_lock
, flags
);
557 if (test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
558 !test_and_set_bit(QUEUE_FLAG_REENTER
,
559 &sdev
->request_queue
->queue_flags
)) {
560 blk_run_queue(sdev
->request_queue
);
561 clear_bit(QUEUE_FLAG_REENTER
,
562 &sdev
->request_queue
->queue_flags
);
564 blk_run_queue(sdev
->request_queue
);
566 spin_lock_irqsave(shost
->host_lock
, flags
);
567 if (unlikely(!list_empty(&sdev
->starved_entry
)))
569 * sdev lost a race, and was put back on the
570 * starved list. This is unlikely but without this
571 * in theory we could loop forever.
575 spin_unlock_irqrestore(shost
->host_lock
, flags
);
581 * Function: scsi_requeue_command()
583 * Purpose: Handle post-processing of completed commands.
585 * Arguments: q - queue to operate on
586 * cmd - command that may need to be requeued.
590 * Notes: After command completion, there may be blocks left
591 * over which weren't finished by the previous command
592 * this can be for a number of reasons - the main one is
593 * I/O errors in the middle of the request, in which case
594 * we need to request the blocks that come after the bad
596 * Notes: Upon return, cmd is a stale pointer.
598 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
600 struct request
*req
= cmd
->request
;
603 scsi_unprep_request(req
);
604 spin_lock_irqsave(q
->queue_lock
, flags
);
605 blk_requeue_request(q
, req
);
606 spin_unlock_irqrestore(q
->queue_lock
, flags
);
611 void scsi_next_command(struct scsi_cmnd
*cmd
)
613 struct scsi_device
*sdev
= cmd
->device
;
614 struct request_queue
*q
= sdev
->request_queue
;
616 /* need to hold a reference on the device before we let go of the cmd */
617 get_device(&sdev
->sdev_gendev
);
619 scsi_put_command(cmd
);
622 /* ok to remove device now */
623 put_device(&sdev
->sdev_gendev
);
626 void scsi_run_host_queues(struct Scsi_Host
*shost
)
628 struct scsi_device
*sdev
;
630 shost_for_each_device(sdev
, shost
)
631 scsi_run_queue(sdev
->request_queue
);
635 * Function: scsi_end_request()
637 * Purpose: Post-processing of completed commands (usually invoked at end
638 * of upper level post-processing and scsi_io_completion).
640 * Arguments: cmd - command that is complete.
641 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
642 * bytes - number of bytes of completed I/O
643 * requeue - indicates whether we should requeue leftovers.
645 * Lock status: Assumed that lock is not held upon entry.
647 * Returns: cmd if requeue required, NULL otherwise.
649 * Notes: This is called for block device requests in order to
650 * mark some number of sectors as complete.
652 * We are guaranteeing that the request queue will be goosed
653 * at some point during this call.
654 * Notes: If cmd was requeued, upon return it will be a stale pointer.
656 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
657 int bytes
, int requeue
)
659 request_queue_t
*q
= cmd
->device
->request_queue
;
660 struct request
*req
= cmd
->request
;
664 * If there are blocks left over at the end, set up the command
665 * to queue the remainder of them.
667 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
668 int leftover
= (req
->hard_nr_sectors
<< 9);
670 if (blk_pc_request(req
))
671 leftover
= req
->data_len
;
673 /* kill remainder if no retrys */
674 if (!uptodate
&& blk_noretry_request(req
))
675 end_that_request_chunk(req
, 0, leftover
);
679 * Bleah. Leftovers again. Stick the
680 * leftovers in the front of the
681 * queue, and goose the queue again.
683 scsi_requeue_command(q
, cmd
);
690 add_disk_randomness(req
->rq_disk
);
692 spin_lock_irqsave(q
->queue_lock
, flags
);
693 if (blk_rq_tagged(req
))
694 blk_queue_end_tag(q
, req
);
695 end_that_request_last(req
, uptodate
);
696 spin_unlock_irqrestore(q
->queue_lock
, flags
);
699 * This will goose the queue request function at the end, so we don't
700 * need to worry about launching another command.
702 scsi_next_command(cmd
);
706 static struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
708 struct scsi_host_sg_pool
*sgp
;
709 struct scatterlist
*sgl
;
711 BUG_ON(!cmd
->use_sg
);
713 switch (cmd
->use_sg
) {
723 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
727 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
731 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
742 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
743 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
747 static void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
749 struct scsi_host_sg_pool
*sgp
;
751 BUG_ON(index
>= SG_MEMPOOL_NR
);
753 sgp
= scsi_sg_pools
+ index
;
754 mempool_free(sgl
, sgp
->pool
);
758 * Function: scsi_release_buffers()
760 * Purpose: Completion processing for block device I/O requests.
762 * Arguments: cmd - command that we are bailing.
764 * Lock status: Assumed that no lock is held upon entry.
768 * Notes: In the event that an upper level driver rejects a
769 * command, we must release resources allocated during
770 * the __init_io() function. Primarily this would involve
771 * the scatter-gather table, and potentially any bounce
774 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
777 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
780 * Zero these out. They now point to freed memory, and it is
781 * dangerous to hang onto the pointers.
783 cmd
->request_buffer
= NULL
;
784 cmd
->request_bufflen
= 0;
788 * Function: scsi_io_completion()
790 * Purpose: Completion processing for block device I/O requests.
792 * Arguments: cmd - command that is finished.
794 * Lock status: Assumed that no lock is held upon entry.
798 * Notes: This function is matched in terms of capabilities to
799 * the function that created the scatter-gather list.
800 * In other words, if there are no bounce buffers
801 * (the normal case for most drivers), we don't need
802 * the logic to deal with cleaning up afterwards.
804 * We must do one of several things here:
806 * a) Call scsi_end_request. This will finish off the
807 * specified number of sectors. If we are done, the
808 * command block will be released, and the queue
809 * function will be goosed. If we are not done, then
810 * scsi_end_request will directly goose the queue.
812 * b) We can just use scsi_requeue_command() here. This would
813 * be used if we just wanted to retry, for example.
815 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
817 int result
= cmd
->result
;
818 int this_count
= cmd
->request_bufflen
;
819 request_queue_t
*q
= cmd
->device
->request_queue
;
820 struct request
*req
= cmd
->request
;
821 int clear_errors
= 1;
822 struct scsi_sense_hdr sshdr
;
824 int sense_deferred
= 0;
826 scsi_release_buffers(cmd
);
829 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
831 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
834 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
835 req
->errors
= result
;
838 if (sense_valid
&& req
->sense
) {
840 * SG_IO wants current and deferred errors
842 int len
= 8 + cmd
->sense_buffer
[7];
844 if (len
> SCSI_SENSE_BUFFERSIZE
)
845 len
= SCSI_SENSE_BUFFERSIZE
;
846 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
847 req
->sense_len
= len
;
850 req
->data_len
= cmd
->resid
;
854 * Next deal with any sectors which we were able to correctly
857 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
859 req
->nr_sectors
, good_bytes
));
860 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
865 /* A number of bytes were successfully read. If there
866 * are leftovers and there is some kind of error
867 * (result != 0), retry the rest.
869 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
872 /* good_bytes = 0, or (inclusive) there were leftovers and
873 * result = 0, so scsi_end_request couldn't retry.
875 if (sense_valid
&& !sense_deferred
) {
876 switch (sshdr
.sense_key
) {
878 if (cmd
->device
->removable
) {
879 /* Detected disc change. Set a bit
880 * and quietly refuse further access.
882 cmd
->device
->changed
= 1;
883 scsi_end_request(cmd
, 0, this_count
, 1);
886 /* Must have been a power glitch, or a
887 * bus reset. Could not have been a
888 * media change, so we just retry the
889 * request and see what happens.
891 scsi_requeue_command(q
, cmd
);
895 case ILLEGAL_REQUEST
:
896 /* If we had an ILLEGAL REQUEST returned, then
897 * we may have performed an unsupported
898 * command. The only thing this should be
899 * would be a ten byte read where only a six
900 * byte read was supported. Also, on a system
901 * where READ CAPACITY failed, we may have
902 * read past the end of the disk.
904 if ((cmd
->device
->use_10_for_rw
&&
905 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
906 (cmd
->cmnd
[0] == READ_10
||
907 cmd
->cmnd
[0] == WRITE_10
)) {
908 cmd
->device
->use_10_for_rw
= 0;
909 /* This will cause a retry with a
912 scsi_requeue_command(q
, cmd
);
915 scsi_end_request(cmd
, 0, this_count
, 1);
920 /* If the device is in the process of becoming
921 * ready, or has a temporary blockage, retry.
923 if (sshdr
.asc
== 0x04) {
924 switch (sshdr
.ascq
) {
925 case 0x01: /* becoming ready */
926 case 0x04: /* format in progress */
927 case 0x05: /* rebuild in progress */
928 case 0x06: /* recalculation in progress */
929 case 0x07: /* operation in progress */
930 case 0x08: /* Long write in progress */
931 case 0x09: /* self test in progress */
932 scsi_requeue_command(q
, cmd
);
938 if (!(req
->cmd_flags
& REQ_QUIET
)) {
939 scmd_printk(KERN_INFO
, cmd
,
940 "Device not ready: ");
941 scsi_print_sense_hdr("", &sshdr
);
943 scsi_end_request(cmd
, 0, this_count
, 1);
945 case VOLUME_OVERFLOW
:
946 if (!(req
->cmd_flags
& REQ_QUIET
)) {
947 scmd_printk(KERN_INFO
, cmd
,
948 "Volume overflow, CDB: ");
949 __scsi_print_command(cmd
->cmnd
);
950 scsi_print_sense("", cmd
);
952 /* See SSC3rXX or current. */
953 scsi_end_request(cmd
, 0, this_count
, 1);
959 if (host_byte(result
) == DID_RESET
) {
960 /* Third party bus reset or reset for error recovery
961 * reasons. Just retry the request and see what
964 scsi_requeue_command(q
, cmd
);
968 if (!(req
->cmd_flags
& REQ_QUIET
)) {
969 scmd_printk(KERN_INFO
, cmd
,
970 "SCSI error: return code = 0x%08x\n",
972 if (driver_byte(result
) & DRIVER_SENSE
)
973 scsi_print_sense("", cmd
);
976 scsi_end_request(cmd
, 0, this_count
, !result
);
978 EXPORT_SYMBOL(scsi_io_completion
);
981 * Function: scsi_init_io()
983 * Purpose: SCSI I/O initialize function.
985 * Arguments: cmd - Command descriptor we wish to initialize
987 * Returns: 0 on success
988 * BLKPREP_DEFER if the failure is retryable
989 * BLKPREP_KILL if the failure is fatal
991 static int scsi_init_io(struct scsi_cmnd
*cmd
)
993 struct request
*req
= cmd
->request
;
994 struct scatterlist
*sgpnt
;
998 * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
1000 if (blk_pc_request(req
) && !req
->bio
) {
1001 cmd
->request_bufflen
= req
->data_len
;
1002 cmd
->request_buffer
= req
->data
;
1003 req
->buffer
= req
->data
;
1009 * we used to not use scatter-gather for single segment request,
1010 * but now we do (it makes highmem I/O easier to support without
1013 cmd
->use_sg
= req
->nr_phys_segments
;
1016 * if sg table allocation fails, requeue request later.
1018 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
1019 if (unlikely(!sgpnt
)) {
1020 scsi_unprep_request(req
);
1021 return BLKPREP_DEFER
;
1024 cmd
->request_buffer
= (char *) sgpnt
;
1025 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1026 if (blk_pc_request(req
))
1027 cmd
->request_bufflen
= req
->data_len
;
1031 * Next, walk the list, and fill in the addresses and sizes of
1034 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1037 * mapped well, send it off
1039 if (likely(count
<= cmd
->use_sg
)) {
1040 cmd
->use_sg
= count
;
1044 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1045 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1046 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1047 req
->current_nr_sectors
);
1049 /* release the command and kill it */
1050 scsi_release_buffers(cmd
);
1051 scsi_put_command(cmd
);
1052 return BLKPREP_KILL
;
1055 static int scsi_issue_flush_fn(request_queue_t
*q
, struct gendisk
*disk
,
1056 sector_t
*error_sector
)
1058 struct scsi_device
*sdev
= q
->queuedata
;
1059 struct scsi_driver
*drv
;
1061 if (sdev
->sdev_state
!= SDEV_RUNNING
)
1064 drv
= *(struct scsi_driver
**) disk
->private_data
;
1065 if (drv
->issue_flush
)
1066 return drv
->issue_flush(&sdev
->sdev_gendev
, error_sector
);
1071 static void scsi_blk_pc_done(struct scsi_cmnd
*cmd
)
1073 BUG_ON(!blk_pc_request(cmd
->request
));
1075 * This will complete the whole command with uptodate=1 so
1076 * as far as the block layer is concerned the command completed
1077 * successfully. Since this is a REQ_BLOCK_PC command the
1078 * caller should check the request's errors value
1080 scsi_io_completion(cmd
, cmd
->request_bufflen
);
1083 static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd
*cmd
)
1085 struct request
*req
= cmd
->request
;
1087 BUG_ON(sizeof(req
->cmd
) > sizeof(cmd
->cmnd
));
1088 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1089 cmd
->cmd_len
= req
->cmd_len
;
1091 cmd
->sc_data_direction
= DMA_NONE
;
1092 else if (rq_data_dir(req
) == WRITE
)
1093 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1095 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1097 cmd
->transfersize
= req
->data_len
;
1098 cmd
->allowed
= req
->retries
;
1099 cmd
->timeout_per_command
= req
->timeout
;
1100 cmd
->done
= scsi_blk_pc_done
;
1103 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1105 struct scsi_device
*sdev
= q
->queuedata
;
1106 struct scsi_cmnd
*cmd
;
1107 int specials_only
= 0;
1110 * Just check to see if the device is online. If it isn't, we
1111 * refuse to process any commands. The device must be brought
1112 * online before trying any recovery commands
1114 if (unlikely(!scsi_device_online(sdev
))) {
1115 sdev_printk(KERN_ERR
, sdev
,
1116 "rejecting I/O to offline device\n");
1119 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1120 /* OK, we're not in a running state don't prep
1122 if (sdev
->sdev_state
== SDEV_DEL
) {
1123 /* Device is fully deleted, no commands
1124 * at all allowed down */
1125 sdev_printk(KERN_ERR
, sdev
,
1126 "rejecting I/O to dead device\n");
1129 /* OK, we only allow special commands (i.e. not
1130 * user initiated ones */
1131 specials_only
= sdev
->sdev_state
;
1135 * Find the actual device driver associated with this command.
1136 * The SPECIAL requests are things like character device or
1137 * ioctls, which did not originate from ll_rw_blk. Note that
1138 * the special field is also used to indicate the cmd for
1139 * the remainder of a partially fulfilled request that can
1140 * come up when there is a medium error. We have to treat
1141 * these two cases differently. We differentiate by looking
1142 * at request->cmd, as this tells us the real story.
1144 if (blk_special_request(req
) && req
->special
)
1146 else if (blk_pc_request(req
) || blk_fs_request(req
)) {
1147 if (unlikely(specials_only
) && !(req
->cmd_flags
& REQ_PREEMPT
)){
1148 if (specials_only
== SDEV_QUIESCE
||
1149 specials_only
== SDEV_BLOCK
)
1152 sdev_printk(KERN_ERR
, sdev
,
1153 "rejecting I/O to device being removed\n");
1158 * Now try and find a command block that we can use.
1160 if (!req
->special
) {
1161 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1167 /* pull a tag out of the request if we have one */
1168 cmd
->tag
= req
->tag
;
1170 blk_dump_rq_flags(req
, "SCSI bad req");
1174 /* note the overloading of req->special. When the tag
1175 * is active it always means cmd. If the tag goes
1176 * back for re-queueing, it may be reset */
1181 * FIXME: drop the lock here because the functions below
1182 * expect to be called without the queue lock held. Also,
1183 * previously, we dequeued the request before dropping the
1184 * lock. We hope REQ_STARTED prevents anything untoward from
1187 if (blk_fs_request(req
) || blk_pc_request(req
)) {
1191 * This will do a couple of things:
1192 * 1) Fill in the actual SCSI command.
1193 * 2) Fill in any other upper-level specific fields
1196 * If this returns 0, it means that the request failed
1197 * (reading past end of disk, reading offline device,
1198 * etc). This won't actually talk to the device, but
1199 * some kinds of consistency checking may cause the
1200 * request to be rejected immediately.
1204 * This sets up the scatter-gather table (allocating if
1207 ret
= scsi_init_io(cmd
);
1209 /* For BLKPREP_KILL/DEFER the cmd was released */
1217 * Initialize the actual SCSI command for this request.
1219 if (blk_pc_request(req
)) {
1220 scsi_setup_blk_pc_cmnd(cmd
);
1221 } else if (req
->rq_disk
) {
1222 struct scsi_driver
*drv
;
1224 drv
= *(struct scsi_driver
**)req
->rq_disk
->private_data
;
1225 if (unlikely(!drv
->init_command(cmd
))) {
1226 scsi_release_buffers(cmd
);
1227 scsi_put_command(cmd
);
1234 * The request is now prepped, no need to come back here
1236 req
->cmd_flags
|= REQ_DONTPREP
;
1240 /* If we defer, the elv_next_request() returns NULL, but the
1241 * queue must be restarted, so we plug here if no returning
1242 * command will automatically do that. */
1243 if (sdev
->device_busy
== 0)
1245 return BLKPREP_DEFER
;
1247 req
->errors
= DID_NO_CONNECT
<< 16;
1248 return BLKPREP_KILL
;
1252 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1255 * Called with the queue_lock held.
1257 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1258 struct scsi_device
*sdev
)
1260 if (sdev
->device_busy
>= sdev
->queue_depth
)
1262 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1264 * unblock after device_blocked iterates to zero
1266 if (--sdev
->device_blocked
== 0) {
1268 sdev_printk(KERN_INFO
, sdev
,
1269 "unblocking device at zero depth\n"));
1275 if (sdev
->device_blocked
)
1282 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1283 * return 0. We must end up running the queue again whenever 0 is
1284 * returned, else IO can hang.
1286 * Called with host_lock held.
1288 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1289 struct Scsi_Host
*shost
,
1290 struct scsi_device
*sdev
)
1292 if (scsi_host_in_recovery(shost
))
1294 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1296 * unblock after host_blocked iterates to zero
1298 if (--shost
->host_blocked
== 0) {
1300 printk("scsi%d unblocking host at zero depth\n",
1307 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1308 shost
->host_blocked
|| shost
->host_self_blocked
) {
1309 if (list_empty(&sdev
->starved_entry
))
1310 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1314 /* We're OK to process the command, so we can't be starved */
1315 if (!list_empty(&sdev
->starved_entry
))
1316 list_del_init(&sdev
->starved_entry
);
1322 * Kill a request for a dead device
1324 static void scsi_kill_request(struct request
*req
, request_queue_t
*q
)
1326 struct scsi_cmnd
*cmd
= req
->special
;
1327 struct scsi_device
*sdev
= cmd
->device
;
1328 struct Scsi_Host
*shost
= sdev
->host
;
1330 blkdev_dequeue_request(req
);
1332 if (unlikely(cmd
== NULL
)) {
1333 printk(KERN_CRIT
"impossible request in %s.\n",
1338 scsi_init_cmd_errh(cmd
);
1339 cmd
->result
= DID_NO_CONNECT
<< 16;
1340 atomic_inc(&cmd
->device
->iorequest_cnt
);
1343 * SCSI request completion path will do scsi_device_unbusy(),
1344 * bump busy counts. To bump the counters, we need to dance
1345 * with the locks as normal issue path does.
1347 sdev
->device_busy
++;
1348 spin_unlock(sdev
->request_queue
->queue_lock
);
1349 spin_lock(shost
->host_lock
);
1351 spin_unlock(shost
->host_lock
);
1352 spin_lock(sdev
->request_queue
->queue_lock
);
1357 static void scsi_softirq_done(struct request
*rq
)
1359 struct scsi_cmnd
*cmd
= rq
->completion_data
;
1360 unsigned long wait_for
= (cmd
->allowed
+ 1) * cmd
->timeout_per_command
;
1363 INIT_LIST_HEAD(&cmd
->eh_entry
);
1365 disposition
= scsi_decide_disposition(cmd
);
1366 if (disposition
!= SUCCESS
&&
1367 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1368 sdev_printk(KERN_ERR
, cmd
->device
,
1369 "timing out command, waited %lus\n",
1371 disposition
= SUCCESS
;
1374 scsi_log_completion(cmd
, disposition
);
1376 switch (disposition
) {
1378 scsi_finish_command(cmd
);
1381 scsi_retry_command(cmd
);
1383 case ADD_TO_MLQUEUE
:
1384 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1387 if (!scsi_eh_scmd_add(cmd
, 0))
1388 scsi_finish_command(cmd
);
1393 * Function: scsi_request_fn()
1395 * Purpose: Main strategy routine for SCSI.
1397 * Arguments: q - Pointer to actual queue.
1401 * Lock status: IO request lock assumed to be held when called.
1403 static void scsi_request_fn(struct request_queue
*q
)
1405 struct scsi_device
*sdev
= q
->queuedata
;
1406 struct Scsi_Host
*shost
;
1407 struct scsi_cmnd
*cmd
;
1408 struct request
*req
;
1411 printk("scsi: killing requests for dead queue\n");
1412 while ((req
= elv_next_request(q
)) != NULL
)
1413 scsi_kill_request(req
, q
);
1417 if(!get_device(&sdev
->sdev_gendev
))
1418 /* We must be tearing the block queue down already */
1422 * To start with, we keep looping until the queue is empty, or until
1423 * the host is no longer able to accept any more requests.
1426 while (!blk_queue_plugged(q
)) {
1429 * get next queueable request. We do this early to make sure
1430 * that the request is fully prepared even if we cannot
1433 req
= elv_next_request(q
);
1434 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1437 if (unlikely(!scsi_device_online(sdev
))) {
1438 sdev_printk(KERN_ERR
, sdev
,
1439 "rejecting I/O to offline device\n");
1440 scsi_kill_request(req
, q
);
1446 * Remove the request from the request list.
1448 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1449 blkdev_dequeue_request(req
);
1450 sdev
->device_busy
++;
1452 spin_unlock(q
->queue_lock
);
1454 if (unlikely(cmd
== NULL
)) {
1455 printk(KERN_CRIT
"impossible request in %s.\n"
1456 "please mail a stack trace to "
1457 "linux-scsi@vger.kernel.org\n",
1459 blk_dump_rq_flags(req
, "foo");
1462 spin_lock(shost
->host_lock
);
1464 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1466 if (sdev
->single_lun
) {
1467 if (scsi_target(sdev
)->starget_sdev_user
&&
1468 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1470 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1475 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1476 * take the lock again.
1478 spin_unlock_irq(shost
->host_lock
);
1481 * Finally, initialize any error handling parameters, and set up
1482 * the timers for timeouts.
1484 scsi_init_cmd_errh(cmd
);
1487 * Dispatch the command to the low-level driver.
1489 rtn
= scsi_dispatch_cmd(cmd
);
1490 spin_lock_irq(q
->queue_lock
);
1492 /* we're refusing the command; because of
1493 * the way locks get dropped, we need to
1494 * check here if plugging is required */
1495 if(sdev
->device_busy
== 0)
1505 spin_unlock_irq(shost
->host_lock
);
1508 * lock q, handle tag, requeue req, and decrement device_busy. We
1509 * must return with queue_lock held.
1511 * Decrementing device_busy without checking it is OK, as all such
1512 * cases (host limits or settings) should run the queue at some
1515 spin_lock_irq(q
->queue_lock
);
1516 blk_requeue_request(q
, req
);
1517 sdev
->device_busy
--;
1518 if(sdev
->device_busy
== 0)
1521 /* must be careful here...if we trigger the ->remove() function
1522 * we cannot be holding the q lock */
1523 spin_unlock_irq(q
->queue_lock
);
1524 put_device(&sdev
->sdev_gendev
);
1525 spin_lock_irq(q
->queue_lock
);
1528 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1530 struct device
*host_dev
;
1531 u64 bounce_limit
= 0xffffffff;
1533 if (shost
->unchecked_isa_dma
)
1534 return BLK_BOUNCE_ISA
;
1536 * Platforms with virtual-DMA translation
1537 * hardware have no practical limit.
1539 if (!PCI_DMA_BUS_IS_PHYS
)
1540 return BLK_BOUNCE_ANY
;
1542 host_dev
= scsi_get_device(shost
);
1543 if (host_dev
&& host_dev
->dma_mask
)
1544 bounce_limit
= *host_dev
->dma_mask
;
1546 return bounce_limit
;
1548 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1550 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1552 struct Scsi_Host
*shost
= sdev
->host
;
1553 struct request_queue
*q
;
1555 q
= blk_init_queue(scsi_request_fn
, NULL
);
1559 blk_queue_prep_rq(q
, scsi_prep_fn
);
1561 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1562 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1563 blk_queue_max_sectors(q
, shost
->max_sectors
);
1564 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1565 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1566 blk_queue_issue_flush_fn(q
, scsi_issue_flush_fn
);
1567 blk_queue_softirq_done(q
, scsi_softirq_done
);
1569 if (!shost
->use_clustering
)
1570 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1574 void scsi_free_queue(struct request_queue
*q
)
1576 blk_cleanup_queue(q
);
1580 * Function: scsi_block_requests()
1582 * Purpose: Utility function used by low-level drivers to prevent further
1583 * commands from being queued to the device.
1585 * Arguments: shost - Host in question
1589 * Lock status: No locks are assumed held.
1591 * Notes: There is no timer nor any other means by which the requests
1592 * get unblocked other than the low-level driver calling
1593 * scsi_unblock_requests().
1595 void scsi_block_requests(struct Scsi_Host
*shost
)
1597 shost
->host_self_blocked
= 1;
1599 EXPORT_SYMBOL(scsi_block_requests
);
1602 * Function: scsi_unblock_requests()
1604 * Purpose: Utility function used by low-level drivers to allow further
1605 * commands from being queued to the device.
1607 * Arguments: shost - Host in question
1611 * Lock status: No locks are assumed held.
1613 * Notes: There is no timer nor any other means by which the requests
1614 * get unblocked other than the low-level driver calling
1615 * scsi_unblock_requests().
1617 * This is done as an API function so that changes to the
1618 * internals of the scsi mid-layer won't require wholesale
1619 * changes to drivers that use this feature.
1621 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1623 shost
->host_self_blocked
= 0;
1624 scsi_run_host_queues(shost
);
1626 EXPORT_SYMBOL(scsi_unblock_requests
);
1628 int __init
scsi_init_queue(void)
1632 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1633 sizeof(struct scsi_io_context
),
1635 if (!scsi_io_context_cache
) {
1636 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1640 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1641 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1642 int size
= sgp
->size
* sizeof(struct scatterlist
);
1644 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1645 SLAB_HWCACHE_ALIGN
, NULL
, NULL
);
1647 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1651 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1654 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1662 void scsi_exit_queue(void)
1666 kmem_cache_destroy(scsi_io_context_cache
);
1668 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1669 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1670 mempool_destroy(sgp
->pool
);
1671 kmem_cache_destroy(sgp
->slab
);
1676 * scsi_mode_select - issue a mode select
1677 * @sdev: SCSI device to be queried
1678 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1679 * @sp: Save page bit (0 == don't save, 1 == save)
1680 * @modepage: mode page being requested
1681 * @buffer: request buffer (may not be smaller than eight bytes)
1682 * @len: length of request buffer.
1683 * @timeout: command timeout
1684 * @retries: number of retries before failing
1685 * @data: returns a structure abstracting the mode header data
1686 * @sense: place to put sense data (or NULL if no sense to be collected).
1687 * must be SCSI_SENSE_BUFFERSIZE big.
1689 * Returns zero if successful; negative error number or scsi
1694 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1695 unsigned char *buffer
, int len
, int timeout
, int retries
,
1696 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1698 unsigned char cmd
[10];
1699 unsigned char *real_buffer
;
1702 memset(cmd
, 0, sizeof(cmd
));
1703 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1705 if (sdev
->use_10_for_ms
) {
1708 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1711 memcpy(real_buffer
+ 8, buffer
, len
);
1715 real_buffer
[2] = data
->medium_type
;
1716 real_buffer
[3] = data
->device_specific
;
1717 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1719 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1720 real_buffer
[7] = data
->block_descriptor_length
;
1722 cmd
[0] = MODE_SELECT_10
;
1726 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1730 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1733 memcpy(real_buffer
+ 4, buffer
, len
);
1736 real_buffer
[1] = data
->medium_type
;
1737 real_buffer
[2] = data
->device_specific
;
1738 real_buffer
[3] = data
->block_descriptor_length
;
1741 cmd
[0] = MODE_SELECT
;
1745 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1746 sshdr
, timeout
, retries
);
1750 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1753 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1754 * six bytes if necessary.
1755 * @sdev: SCSI device to be queried
1756 * @dbd: set if mode sense will allow block descriptors to be returned
1757 * @modepage: mode page being requested
1758 * @buffer: request buffer (may not be smaller than eight bytes)
1759 * @len: length of request buffer.
1760 * @timeout: command timeout
1761 * @retries: number of retries before failing
1762 * @data: returns a structure abstracting the mode header data
1763 * @sense: place to put sense data (or NULL if no sense to be collected).
1764 * must be SCSI_SENSE_BUFFERSIZE big.
1766 * Returns zero if unsuccessful, or the header offset (either 4
1767 * or 8 depending on whether a six or ten byte command was
1768 * issued) if successful.
1771 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1772 unsigned char *buffer
, int len
, int timeout
, int retries
,
1773 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1775 unsigned char cmd
[12];
1779 struct scsi_sense_hdr my_sshdr
;
1781 memset(data
, 0, sizeof(*data
));
1782 memset(&cmd
[0], 0, 12);
1783 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1786 /* caller might not be interested in sense, but we need it */
1791 use_10_for_ms
= sdev
->use_10_for_ms
;
1793 if (use_10_for_ms
) {
1797 cmd
[0] = MODE_SENSE_10
;
1804 cmd
[0] = MODE_SENSE
;
1809 memset(buffer
, 0, len
);
1811 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1812 sshdr
, timeout
, retries
);
1814 /* This code looks awful: what it's doing is making sure an
1815 * ILLEGAL REQUEST sense return identifies the actual command
1816 * byte as the problem. MODE_SENSE commands can return
1817 * ILLEGAL REQUEST if the code page isn't supported */
1819 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1820 (driver_byte(result
) & DRIVER_SENSE
)) {
1821 if (scsi_sense_valid(sshdr
)) {
1822 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1823 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1825 * Invalid command operation code
1827 sdev
->use_10_for_ms
= 0;
1833 if(scsi_status_is_good(result
)) {
1834 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1835 (modepage
== 6 || modepage
== 8))) {
1836 /* Initio breakage? */
1839 data
->medium_type
= 0;
1840 data
->device_specific
= 0;
1842 data
->block_descriptor_length
= 0;
1843 } else if(use_10_for_ms
) {
1844 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1845 data
->medium_type
= buffer
[2];
1846 data
->device_specific
= buffer
[3];
1847 data
->longlba
= buffer
[4] & 0x01;
1848 data
->block_descriptor_length
= buffer
[6]*256
1851 data
->length
= buffer
[0] + 1;
1852 data
->medium_type
= buffer
[1];
1853 data
->device_specific
= buffer
[2];
1854 data
->block_descriptor_length
= buffer
[3];
1856 data
->header_length
= header_length
;
1861 EXPORT_SYMBOL(scsi_mode_sense
);
1864 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1867 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1869 struct scsi_sense_hdr sshdr
;
1872 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1875 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1877 if ((scsi_sense_valid(&sshdr
)) &&
1878 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1879 (sshdr
.sense_key
== NOT_READY
))) {
1886 EXPORT_SYMBOL(scsi_test_unit_ready
);
1889 * scsi_device_set_state - Take the given device through the device
1891 * @sdev: scsi device to change the state of.
1892 * @state: state to change to.
1894 * Returns zero if unsuccessful or an error if the requested
1895 * transition is illegal.
1898 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1900 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1902 if (state
== oldstate
)
1907 /* There are no legal states that come back to
1908 * created. This is the manually initialised start
1982 sdev
->sdev_state
= state
;
1986 SCSI_LOG_ERROR_RECOVERY(1,
1987 sdev_printk(KERN_ERR
, sdev
,
1988 "Illegal state transition %s->%s\n",
1989 scsi_device_state_name(oldstate
),
1990 scsi_device_state_name(state
))
1994 EXPORT_SYMBOL(scsi_device_set_state
);
1997 * scsi_device_quiesce - Block user issued commands.
1998 * @sdev: scsi device to quiesce.
2000 * This works by trying to transition to the SDEV_QUIESCE state
2001 * (which must be a legal transition). When the device is in this
2002 * state, only special requests will be accepted, all others will
2003 * be deferred. Since special requests may also be requeued requests,
2004 * a successful return doesn't guarantee the device will be
2005 * totally quiescent.
2007 * Must be called with user context, may sleep.
2009 * Returns zero if unsuccessful or an error if not.
2012 scsi_device_quiesce(struct scsi_device
*sdev
)
2014 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2018 scsi_run_queue(sdev
->request_queue
);
2019 while (sdev
->device_busy
) {
2020 msleep_interruptible(200);
2021 scsi_run_queue(sdev
->request_queue
);
2025 EXPORT_SYMBOL(scsi_device_quiesce
);
2028 * scsi_device_resume - Restart user issued commands to a quiesced device.
2029 * @sdev: scsi device to resume.
2031 * Moves the device from quiesced back to running and restarts the
2034 * Must be called with user context, may sleep.
2037 scsi_device_resume(struct scsi_device
*sdev
)
2039 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2041 scsi_run_queue(sdev
->request_queue
);
2043 EXPORT_SYMBOL(scsi_device_resume
);
2046 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2048 scsi_device_quiesce(sdev
);
2052 scsi_target_quiesce(struct scsi_target
*starget
)
2054 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2056 EXPORT_SYMBOL(scsi_target_quiesce
);
2059 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2061 scsi_device_resume(sdev
);
2065 scsi_target_resume(struct scsi_target
*starget
)
2067 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2069 EXPORT_SYMBOL(scsi_target_resume
);
2072 * scsi_internal_device_block - internal function to put a device
2073 * temporarily into the SDEV_BLOCK state
2074 * @sdev: device to block
2076 * Block request made by scsi lld's to temporarily stop all
2077 * scsi commands on the specified device. Called from interrupt
2078 * or normal process context.
2080 * Returns zero if successful or error if not
2083 * This routine transitions the device to the SDEV_BLOCK state
2084 * (which must be a legal transition). When the device is in this
2085 * state, all commands are deferred until the scsi lld reenables
2086 * the device with scsi_device_unblock or device_block_tmo fires.
2087 * This routine assumes the host_lock is held on entry.
2090 scsi_internal_device_block(struct scsi_device
*sdev
)
2092 request_queue_t
*q
= sdev
->request_queue
;
2093 unsigned long flags
;
2096 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2101 * The device has transitioned to SDEV_BLOCK. Stop the
2102 * block layer from calling the midlayer with this device's
2105 spin_lock_irqsave(q
->queue_lock
, flags
);
2107 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2111 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2114 * scsi_internal_device_unblock - resume a device after a block request
2115 * @sdev: device to resume
2117 * Called by scsi lld's or the midlayer to restart the device queue
2118 * for the previously suspended scsi device. Called from interrupt or
2119 * normal process context.
2121 * Returns zero if successful or error if not.
2124 * This routine transitions the device to the SDEV_RUNNING state
2125 * (which must be a legal transition) allowing the midlayer to
2126 * goose the queue for this device. This routine assumes the
2127 * host_lock is held upon entry.
2130 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2132 request_queue_t
*q
= sdev
->request_queue
;
2134 unsigned long flags
;
2137 * Try to transition the scsi device to SDEV_RUNNING
2138 * and goose the device queue if successful.
2140 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2144 spin_lock_irqsave(q
->queue_lock
, flags
);
2146 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2150 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2153 device_block(struct scsi_device
*sdev
, void *data
)
2155 scsi_internal_device_block(sdev
);
2159 target_block(struct device
*dev
, void *data
)
2161 if (scsi_is_target_device(dev
))
2162 starget_for_each_device(to_scsi_target(dev
), NULL
,
2168 scsi_target_block(struct device
*dev
)
2170 if (scsi_is_target_device(dev
))
2171 starget_for_each_device(to_scsi_target(dev
), NULL
,
2174 device_for_each_child(dev
, NULL
, target_block
);
2176 EXPORT_SYMBOL_GPL(scsi_target_block
);
2179 device_unblock(struct scsi_device
*sdev
, void *data
)
2181 scsi_internal_device_unblock(sdev
);
2185 target_unblock(struct device
*dev
, void *data
)
2187 if (scsi_is_target_device(dev
))
2188 starget_for_each_device(to_scsi_target(dev
), NULL
,
2194 scsi_target_unblock(struct device
*dev
)
2196 if (scsi_is_target_device(dev
))
2197 starget_for_each_device(to_scsi_target(dev
), NULL
,
2200 device_for_each_child(dev
, NULL
, target_unblock
);
2202 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2205 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2206 * @sg: scatter-gather list
2207 * @sg_count: number of segments in sg
2208 * @offset: offset in bytes into sg, on return offset into the mapped area
2209 * @len: bytes to map, on return number of bytes mapped
2211 * Returns virtual address of the start of the mapped page
2213 void *scsi_kmap_atomic_sg(struct scatterlist
*sg
, int sg_count
,
2214 size_t *offset
, size_t *len
)
2217 size_t sg_len
= 0, len_complete
= 0;
2220 for (i
= 0; i
< sg_count
; i
++) {
2221 len_complete
= sg_len
; /* Complete sg-entries */
2222 sg_len
+= sg
[i
].length
;
2223 if (sg_len
> *offset
)
2227 if (unlikely(i
== sg_count
)) {
2228 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2230 __FUNCTION__
, sg_len
, *offset
, sg_count
);
2235 /* Offset starting from the beginning of first page in this sg-entry */
2236 *offset
= *offset
- len_complete
+ sg
[i
].offset
;
2238 /* Assumption: contiguous pages can be accessed as "page + i" */
2239 page
= nth_page(sg
[i
].page
, (*offset
>> PAGE_SHIFT
));
2240 *offset
&= ~PAGE_MASK
;
2242 /* Bytes in this sg-entry from *offset to the end of the page */
2243 sg_len
= PAGE_SIZE
- *offset
;
2247 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2249 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2252 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2253 * mapped with scsi_kmap_atomic_sg
2254 * @virt: virtual address to be unmapped
2256 void scsi_kunmap_atomic_sg(void *virt
)
2258 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2260 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);