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 memset(req
->cmd
, 0, BLK_MAX_CDB
); /* ATAPI hates garbage after CDB */
414 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
415 req
->sense
= sioc
->sense
;
417 req
->timeout
= timeout
;
418 req
->retries
= retries
;
419 req
->end_io_data
= sioc
;
421 sioc
->data
= privdata
;
424 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
428 blk_put_request(req
);
430 kmem_cache_free(scsi_io_context_cache
, sioc
);
431 return DRIVER_ERROR
<< 24;
433 EXPORT_SYMBOL_GPL(scsi_execute_async
);
436 * Function: scsi_init_cmd_errh()
438 * Purpose: Initialize cmd fields related to error handling.
440 * Arguments: cmd - command that is ready to be queued.
442 * Notes: This function has the job of initializing a number of
443 * fields related to error handling. Typically this will
444 * be called once for each command, as required.
446 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
448 cmd
->serial_number
= 0;
449 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
450 if (cmd
->cmd_len
== 0)
451 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
454 void scsi_device_unbusy(struct scsi_device
*sdev
)
456 struct Scsi_Host
*shost
= sdev
->host
;
459 spin_lock_irqsave(shost
->host_lock
, flags
);
461 if (unlikely(scsi_host_in_recovery(shost
) &&
462 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
463 scsi_eh_wakeup(shost
);
464 spin_unlock(shost
->host_lock
);
465 spin_lock(sdev
->request_queue
->queue_lock
);
467 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
471 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
472 * and call blk_run_queue for all the scsi_devices on the target -
473 * including current_sdev first.
475 * Called with *no* scsi locks held.
477 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
479 struct Scsi_Host
*shost
= current_sdev
->host
;
480 struct scsi_device
*sdev
, *tmp
;
481 struct scsi_target
*starget
= scsi_target(current_sdev
);
484 spin_lock_irqsave(shost
->host_lock
, flags
);
485 starget
->starget_sdev_user
= NULL
;
486 spin_unlock_irqrestore(shost
->host_lock
, flags
);
489 * Call blk_run_queue for all LUNs on the target, starting with
490 * current_sdev. We race with others (to set starget_sdev_user),
491 * but in most cases, we will be first. Ideally, each LU on the
492 * target would get some limited time or requests on the target.
494 blk_run_queue(current_sdev
->request_queue
);
496 spin_lock_irqsave(shost
->host_lock
, flags
);
497 if (starget
->starget_sdev_user
)
499 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
500 same_target_siblings
) {
501 if (sdev
== current_sdev
)
503 if (scsi_device_get(sdev
))
506 spin_unlock_irqrestore(shost
->host_lock
, flags
);
507 blk_run_queue(sdev
->request_queue
);
508 spin_lock_irqsave(shost
->host_lock
, flags
);
510 scsi_device_put(sdev
);
513 spin_unlock_irqrestore(shost
->host_lock
, flags
);
517 * Function: scsi_run_queue()
519 * Purpose: Select a proper request queue to serve next
521 * Arguments: q - last request's queue
525 * Notes: The previous command was completely finished, start
526 * a new one if possible.
528 static void scsi_run_queue(struct request_queue
*q
)
530 struct scsi_device
*sdev
= q
->queuedata
;
531 struct Scsi_Host
*shost
= sdev
->host
;
534 if (sdev
->single_lun
)
535 scsi_single_lun_run(sdev
);
537 spin_lock_irqsave(shost
->host_lock
, flags
);
538 while (!list_empty(&shost
->starved_list
) &&
539 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
540 !((shost
->can_queue
> 0) &&
541 (shost
->host_busy
>= shost
->can_queue
))) {
543 * As long as shost is accepting commands and we have
544 * starved queues, call blk_run_queue. scsi_request_fn
545 * drops the queue_lock and can add us back to the
548 * host_lock protects the starved_list and starved_entry.
549 * scsi_request_fn must get the host_lock before checking
550 * or modifying starved_list or starved_entry.
552 sdev
= list_entry(shost
->starved_list
.next
,
553 struct scsi_device
, starved_entry
);
554 list_del_init(&sdev
->starved_entry
);
555 spin_unlock_irqrestore(shost
->host_lock
, flags
);
558 if (test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
559 !test_and_set_bit(QUEUE_FLAG_REENTER
,
560 &sdev
->request_queue
->queue_flags
)) {
561 blk_run_queue(sdev
->request_queue
);
562 clear_bit(QUEUE_FLAG_REENTER
,
563 &sdev
->request_queue
->queue_flags
);
565 blk_run_queue(sdev
->request_queue
);
567 spin_lock_irqsave(shost
->host_lock
, flags
);
568 if (unlikely(!list_empty(&sdev
->starved_entry
)))
570 * sdev lost a race, and was put back on the
571 * starved list. This is unlikely but without this
572 * in theory we could loop forever.
576 spin_unlock_irqrestore(shost
->host_lock
, flags
);
582 * Function: scsi_requeue_command()
584 * Purpose: Handle post-processing of completed commands.
586 * Arguments: q - queue to operate on
587 * cmd - command that may need to be requeued.
591 * Notes: After command completion, there may be blocks left
592 * over which weren't finished by the previous command
593 * this can be for a number of reasons - the main one is
594 * I/O errors in the middle of the request, in which case
595 * we need to request the blocks that come after the bad
597 * Notes: Upon return, cmd is a stale pointer.
599 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
601 struct request
*req
= cmd
->request
;
604 scsi_unprep_request(req
);
605 spin_lock_irqsave(q
->queue_lock
, flags
);
606 blk_requeue_request(q
, req
);
607 spin_unlock_irqrestore(q
->queue_lock
, flags
);
612 void scsi_next_command(struct scsi_cmnd
*cmd
)
614 struct scsi_device
*sdev
= cmd
->device
;
615 struct request_queue
*q
= sdev
->request_queue
;
617 /* need to hold a reference on the device before we let go of the cmd */
618 get_device(&sdev
->sdev_gendev
);
620 scsi_put_command(cmd
);
623 /* ok to remove device now */
624 put_device(&sdev
->sdev_gendev
);
627 void scsi_run_host_queues(struct Scsi_Host
*shost
)
629 struct scsi_device
*sdev
;
631 shost_for_each_device(sdev
, shost
)
632 scsi_run_queue(sdev
->request_queue
);
636 * Function: scsi_end_request()
638 * Purpose: Post-processing of completed commands (usually invoked at end
639 * of upper level post-processing and scsi_io_completion).
641 * Arguments: cmd - command that is complete.
642 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
643 * bytes - number of bytes of completed I/O
644 * requeue - indicates whether we should requeue leftovers.
646 * Lock status: Assumed that lock is not held upon entry.
648 * Returns: cmd if requeue required, NULL otherwise.
650 * Notes: This is called for block device requests in order to
651 * mark some number of sectors as complete.
653 * We are guaranteeing that the request queue will be goosed
654 * at some point during this call.
655 * Notes: If cmd was requeued, upon return it will be a stale pointer.
657 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
658 int bytes
, int requeue
)
660 request_queue_t
*q
= cmd
->device
->request_queue
;
661 struct request
*req
= cmd
->request
;
665 * If there are blocks left over at the end, set up the command
666 * to queue the remainder of them.
668 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
669 int leftover
= (req
->hard_nr_sectors
<< 9);
671 if (blk_pc_request(req
))
672 leftover
= req
->data_len
;
674 /* kill remainder if no retrys */
675 if (!uptodate
&& blk_noretry_request(req
))
676 end_that_request_chunk(req
, 0, leftover
);
680 * Bleah. Leftovers again. Stick the
681 * leftovers in the front of the
682 * queue, and goose the queue again.
684 scsi_requeue_command(q
, cmd
);
691 add_disk_randomness(req
->rq_disk
);
693 spin_lock_irqsave(q
->queue_lock
, flags
);
694 if (blk_rq_tagged(req
))
695 blk_queue_end_tag(q
, req
);
696 end_that_request_last(req
, uptodate
);
697 spin_unlock_irqrestore(q
->queue_lock
, flags
);
700 * This will goose the queue request function at the end, so we don't
701 * need to worry about launching another command.
703 scsi_next_command(cmd
);
707 static struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
709 struct scsi_host_sg_pool
*sgp
;
710 struct scatterlist
*sgl
;
712 BUG_ON(!cmd
->use_sg
);
714 switch (cmd
->use_sg
) {
724 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
728 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
732 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
743 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
744 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
748 static void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
750 struct scsi_host_sg_pool
*sgp
;
752 BUG_ON(index
>= SG_MEMPOOL_NR
);
754 sgp
= scsi_sg_pools
+ index
;
755 mempool_free(sgl
, sgp
->pool
);
759 * Function: scsi_release_buffers()
761 * Purpose: Completion processing for block device I/O requests.
763 * Arguments: cmd - command that we are bailing.
765 * Lock status: Assumed that no lock is held upon entry.
769 * Notes: In the event that an upper level driver rejects a
770 * command, we must release resources allocated during
771 * the __init_io() function. Primarily this would involve
772 * the scatter-gather table, and potentially any bounce
775 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
778 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
781 * Zero these out. They now point to freed memory, and it is
782 * dangerous to hang onto the pointers.
784 cmd
->request_buffer
= NULL
;
785 cmd
->request_bufflen
= 0;
789 * Function: scsi_io_completion()
791 * Purpose: Completion processing for block device I/O requests.
793 * Arguments: cmd - command that is finished.
795 * Lock status: Assumed that no lock is held upon entry.
799 * Notes: This function is matched in terms of capabilities to
800 * the function that created the scatter-gather list.
801 * In other words, if there are no bounce buffers
802 * (the normal case for most drivers), we don't need
803 * the logic to deal with cleaning up afterwards.
805 * We must do one of several things here:
807 * a) Call scsi_end_request. This will finish off the
808 * specified number of sectors. If we are done, the
809 * command block will be released, and the queue
810 * function will be goosed. If we are not done, then
811 * scsi_end_request will directly goose the queue.
813 * b) We can just use scsi_requeue_command() here. This would
814 * be used if we just wanted to retry, for example.
816 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
818 int result
= cmd
->result
;
819 int this_count
= cmd
->request_bufflen
;
820 request_queue_t
*q
= cmd
->device
->request_queue
;
821 struct request
*req
= cmd
->request
;
822 int clear_errors
= 1;
823 struct scsi_sense_hdr sshdr
;
825 int sense_deferred
= 0;
827 scsi_release_buffers(cmd
);
830 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
832 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
835 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
836 req
->errors
= result
;
839 if (sense_valid
&& req
->sense
) {
841 * SG_IO wants current and deferred errors
843 int len
= 8 + cmd
->sense_buffer
[7];
845 if (len
> SCSI_SENSE_BUFFERSIZE
)
846 len
= SCSI_SENSE_BUFFERSIZE
;
847 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
848 req
->sense_len
= len
;
851 req
->data_len
= cmd
->resid
;
855 * Next deal with any sectors which we were able to correctly
858 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
860 req
->nr_sectors
, good_bytes
));
861 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
866 /* A number of bytes were successfully read. If there
867 * are leftovers and there is some kind of error
868 * (result != 0), retry the rest.
870 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
873 /* good_bytes = 0, or (inclusive) there were leftovers and
874 * result = 0, so scsi_end_request couldn't retry.
876 if (sense_valid
&& !sense_deferred
) {
877 switch (sshdr
.sense_key
) {
879 if (cmd
->device
->removable
) {
880 /* Detected disc change. Set a bit
881 * and quietly refuse further access.
883 cmd
->device
->changed
= 1;
884 scsi_end_request(cmd
, 0, this_count
, 1);
887 /* Must have been a power glitch, or a
888 * bus reset. Could not have been a
889 * media change, so we just retry the
890 * request and see what happens.
892 scsi_requeue_command(q
, cmd
);
896 case ILLEGAL_REQUEST
:
897 /* If we had an ILLEGAL REQUEST returned, then
898 * we may have performed an unsupported
899 * command. The only thing this should be
900 * would be a ten byte read where only a six
901 * byte read was supported. Also, on a system
902 * where READ CAPACITY failed, we may have
903 * read past the end of the disk.
905 if ((cmd
->device
->use_10_for_rw
&&
906 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
907 (cmd
->cmnd
[0] == READ_10
||
908 cmd
->cmnd
[0] == WRITE_10
)) {
909 cmd
->device
->use_10_for_rw
= 0;
910 /* This will cause a retry with a
913 scsi_requeue_command(q
, cmd
);
916 scsi_end_request(cmd
, 0, this_count
, 1);
921 /* If the device is in the process of becoming
922 * ready, or has a temporary blockage, retry.
924 if (sshdr
.asc
== 0x04) {
925 switch (sshdr
.ascq
) {
926 case 0x01: /* becoming ready */
927 case 0x04: /* format in progress */
928 case 0x05: /* rebuild in progress */
929 case 0x06: /* recalculation in progress */
930 case 0x07: /* operation in progress */
931 case 0x08: /* Long write in progress */
932 case 0x09: /* self test in progress */
933 scsi_requeue_command(q
, cmd
);
939 if (!(req
->cmd_flags
& REQ_QUIET
)) {
940 scmd_printk(KERN_INFO
, cmd
,
941 "Device not ready: ");
942 scsi_print_sense_hdr("", &sshdr
);
944 scsi_end_request(cmd
, 0, this_count
, 1);
946 case VOLUME_OVERFLOW
:
947 if (!(req
->cmd_flags
& REQ_QUIET
)) {
948 scmd_printk(KERN_INFO
, cmd
,
949 "Volume overflow, CDB: ");
950 __scsi_print_command(cmd
->cmnd
);
951 scsi_print_sense("", cmd
);
953 /* See SSC3rXX or current. */
954 scsi_end_request(cmd
, 0, this_count
, 1);
960 if (host_byte(result
) == DID_RESET
) {
961 /* Third party bus reset or reset for error recovery
962 * reasons. Just retry the request and see what
965 scsi_requeue_command(q
, cmd
);
969 if (!(req
->cmd_flags
& REQ_QUIET
)) {
970 scmd_printk(KERN_INFO
, cmd
,
971 "SCSI error: return code = 0x%08x\n",
973 if (driver_byte(result
) & DRIVER_SENSE
)
974 scsi_print_sense("", cmd
);
977 scsi_end_request(cmd
, 0, this_count
, !result
);
979 EXPORT_SYMBOL(scsi_io_completion
);
982 * Function: scsi_init_io()
984 * Purpose: SCSI I/O initialize function.
986 * Arguments: cmd - Command descriptor we wish to initialize
988 * Returns: 0 on success
989 * BLKPREP_DEFER if the failure is retryable
990 * BLKPREP_KILL if the failure is fatal
992 static int scsi_init_io(struct scsi_cmnd
*cmd
)
994 struct request
*req
= cmd
->request
;
995 struct scatterlist
*sgpnt
;
999 * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
1001 if (blk_pc_request(req
) && !req
->bio
) {
1002 cmd
->request_bufflen
= req
->data_len
;
1003 cmd
->request_buffer
= req
->data
;
1004 req
->buffer
= req
->data
;
1010 * we used to not use scatter-gather for single segment request,
1011 * but now we do (it makes highmem I/O easier to support without
1014 cmd
->use_sg
= req
->nr_phys_segments
;
1017 * if sg table allocation fails, requeue request later.
1019 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
1020 if (unlikely(!sgpnt
)) {
1021 scsi_unprep_request(req
);
1022 return BLKPREP_DEFER
;
1025 cmd
->request_buffer
= (char *) sgpnt
;
1026 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1027 if (blk_pc_request(req
))
1028 cmd
->request_bufflen
= req
->data_len
;
1032 * Next, walk the list, and fill in the addresses and sizes of
1035 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1038 * mapped well, send it off
1040 if (likely(count
<= cmd
->use_sg
)) {
1041 cmd
->use_sg
= count
;
1045 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1046 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1047 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1048 req
->current_nr_sectors
);
1050 /* release the command and kill it */
1051 scsi_release_buffers(cmd
);
1052 scsi_put_command(cmd
);
1053 return BLKPREP_KILL
;
1056 static int scsi_issue_flush_fn(request_queue_t
*q
, struct gendisk
*disk
,
1057 sector_t
*error_sector
)
1059 struct scsi_device
*sdev
= q
->queuedata
;
1060 struct scsi_driver
*drv
;
1062 if (sdev
->sdev_state
!= SDEV_RUNNING
)
1065 drv
= *(struct scsi_driver
**) disk
->private_data
;
1066 if (drv
->issue_flush
)
1067 return drv
->issue_flush(&sdev
->sdev_gendev
, error_sector
);
1072 static void scsi_blk_pc_done(struct scsi_cmnd
*cmd
)
1074 BUG_ON(!blk_pc_request(cmd
->request
));
1076 * This will complete the whole command with uptodate=1 so
1077 * as far as the block layer is concerned the command completed
1078 * successfully. Since this is a REQ_BLOCK_PC command the
1079 * caller should check the request's errors value
1081 scsi_io_completion(cmd
, cmd
->request_bufflen
);
1084 static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd
*cmd
)
1086 struct request
*req
= cmd
->request
;
1088 BUILD_BUG_ON(sizeof(req
->cmd
) > sizeof(cmd
->cmnd
));
1089 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1090 cmd
->cmd_len
= req
->cmd_len
;
1092 cmd
->sc_data_direction
= DMA_NONE
;
1093 else if (rq_data_dir(req
) == WRITE
)
1094 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1096 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1098 cmd
->transfersize
= req
->data_len
;
1099 cmd
->allowed
= req
->retries
;
1100 cmd
->timeout_per_command
= req
->timeout
;
1101 cmd
->done
= scsi_blk_pc_done
;
1104 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1106 struct scsi_device
*sdev
= q
->queuedata
;
1107 struct scsi_cmnd
*cmd
;
1108 int specials_only
= 0;
1111 * Just check to see if the device is online. If it isn't, we
1112 * refuse to process any commands. The device must be brought
1113 * online before trying any recovery commands
1115 if (unlikely(!scsi_device_online(sdev
))) {
1116 sdev_printk(KERN_ERR
, sdev
,
1117 "rejecting I/O to offline device\n");
1120 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1121 /* OK, we're not in a running state don't prep
1123 if (sdev
->sdev_state
== SDEV_DEL
) {
1124 /* Device is fully deleted, no commands
1125 * at all allowed down */
1126 sdev_printk(KERN_ERR
, sdev
,
1127 "rejecting I/O to dead device\n");
1130 /* OK, we only allow special commands (i.e. not
1131 * user initiated ones */
1132 specials_only
= sdev
->sdev_state
;
1136 * Find the actual device driver associated with this command.
1137 * The SPECIAL requests are things like character device or
1138 * ioctls, which did not originate from ll_rw_blk. Note that
1139 * the special field is also used to indicate the cmd for
1140 * the remainder of a partially fulfilled request that can
1141 * come up when there is a medium error. We have to treat
1142 * these two cases differently. We differentiate by looking
1143 * at request->cmd, as this tells us the real story.
1145 if (blk_special_request(req
) && req
->special
)
1147 else if (blk_pc_request(req
) || blk_fs_request(req
)) {
1148 if (unlikely(specials_only
) && !(req
->cmd_flags
& REQ_PREEMPT
)){
1149 if (specials_only
== SDEV_QUIESCE
||
1150 specials_only
== SDEV_BLOCK
)
1153 sdev_printk(KERN_ERR
, sdev
,
1154 "rejecting I/O to device being removed\n");
1159 * Now try and find a command block that we can use.
1161 if (!req
->special
) {
1162 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1168 /* pull a tag out of the request if we have one */
1169 cmd
->tag
= req
->tag
;
1171 blk_dump_rq_flags(req
, "SCSI bad req");
1175 /* note the overloading of req->special. When the tag
1176 * is active it always means cmd. If the tag goes
1177 * back for re-queueing, it may be reset */
1182 * FIXME: drop the lock here because the functions below
1183 * expect to be called without the queue lock held. Also,
1184 * previously, we dequeued the request before dropping the
1185 * lock. We hope REQ_STARTED prevents anything untoward from
1188 if (blk_fs_request(req
) || blk_pc_request(req
)) {
1192 * This will do a couple of things:
1193 * 1) Fill in the actual SCSI command.
1194 * 2) Fill in any other upper-level specific fields
1197 * If this returns 0, it means that the request failed
1198 * (reading past end of disk, reading offline device,
1199 * etc). This won't actually talk to the device, but
1200 * some kinds of consistency checking may cause the
1201 * request to be rejected immediately.
1205 * This sets up the scatter-gather table (allocating if
1208 ret
= scsi_init_io(cmd
);
1210 /* For BLKPREP_KILL/DEFER the cmd was released */
1218 * Initialize the actual SCSI command for this request.
1220 if (blk_pc_request(req
)) {
1221 scsi_setup_blk_pc_cmnd(cmd
);
1222 } else if (req
->rq_disk
) {
1223 struct scsi_driver
*drv
;
1225 drv
= *(struct scsi_driver
**)req
->rq_disk
->private_data
;
1226 if (unlikely(!drv
->init_command(cmd
))) {
1227 scsi_release_buffers(cmd
);
1228 scsi_put_command(cmd
);
1235 * The request is now prepped, no need to come back here
1237 req
->cmd_flags
|= REQ_DONTPREP
;
1241 /* If we defer, the elv_next_request() returns NULL, but the
1242 * queue must be restarted, so we plug here if no returning
1243 * command will automatically do that. */
1244 if (sdev
->device_busy
== 0)
1246 return BLKPREP_DEFER
;
1248 req
->errors
= DID_NO_CONNECT
<< 16;
1249 return BLKPREP_KILL
;
1253 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1256 * Called with the queue_lock held.
1258 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1259 struct scsi_device
*sdev
)
1261 if (sdev
->device_busy
>= sdev
->queue_depth
)
1263 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1265 * unblock after device_blocked iterates to zero
1267 if (--sdev
->device_blocked
== 0) {
1269 sdev_printk(KERN_INFO
, sdev
,
1270 "unblocking device at zero depth\n"));
1276 if (sdev
->device_blocked
)
1283 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1284 * return 0. We must end up running the queue again whenever 0 is
1285 * returned, else IO can hang.
1287 * Called with host_lock held.
1289 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1290 struct Scsi_Host
*shost
,
1291 struct scsi_device
*sdev
)
1293 if (scsi_host_in_recovery(shost
))
1295 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1297 * unblock after host_blocked iterates to zero
1299 if (--shost
->host_blocked
== 0) {
1301 printk("scsi%d unblocking host at zero depth\n",
1308 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1309 shost
->host_blocked
|| shost
->host_self_blocked
) {
1310 if (list_empty(&sdev
->starved_entry
))
1311 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1315 /* We're OK to process the command, so we can't be starved */
1316 if (!list_empty(&sdev
->starved_entry
))
1317 list_del_init(&sdev
->starved_entry
);
1323 * Kill a request for a dead device
1325 static void scsi_kill_request(struct request
*req
, request_queue_t
*q
)
1327 struct scsi_cmnd
*cmd
= req
->special
;
1328 struct scsi_device
*sdev
= cmd
->device
;
1329 struct Scsi_Host
*shost
= sdev
->host
;
1331 blkdev_dequeue_request(req
);
1333 if (unlikely(cmd
== NULL
)) {
1334 printk(KERN_CRIT
"impossible request in %s.\n",
1339 scsi_init_cmd_errh(cmd
);
1340 cmd
->result
= DID_NO_CONNECT
<< 16;
1341 atomic_inc(&cmd
->device
->iorequest_cnt
);
1344 * SCSI request completion path will do scsi_device_unbusy(),
1345 * bump busy counts. To bump the counters, we need to dance
1346 * with the locks as normal issue path does.
1348 sdev
->device_busy
++;
1349 spin_unlock(sdev
->request_queue
->queue_lock
);
1350 spin_lock(shost
->host_lock
);
1352 spin_unlock(shost
->host_lock
);
1353 spin_lock(sdev
->request_queue
->queue_lock
);
1358 static void scsi_softirq_done(struct request
*rq
)
1360 struct scsi_cmnd
*cmd
= rq
->completion_data
;
1361 unsigned long wait_for
= (cmd
->allowed
+ 1) * cmd
->timeout_per_command
;
1364 INIT_LIST_HEAD(&cmd
->eh_entry
);
1366 disposition
= scsi_decide_disposition(cmd
);
1367 if (disposition
!= SUCCESS
&&
1368 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1369 sdev_printk(KERN_ERR
, cmd
->device
,
1370 "timing out command, waited %lus\n",
1372 disposition
= SUCCESS
;
1375 scsi_log_completion(cmd
, disposition
);
1377 switch (disposition
) {
1379 scsi_finish_command(cmd
);
1382 scsi_retry_command(cmd
);
1384 case ADD_TO_MLQUEUE
:
1385 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1388 if (!scsi_eh_scmd_add(cmd
, 0))
1389 scsi_finish_command(cmd
);
1394 * Function: scsi_request_fn()
1396 * Purpose: Main strategy routine for SCSI.
1398 * Arguments: q - Pointer to actual queue.
1402 * Lock status: IO request lock assumed to be held when called.
1404 static void scsi_request_fn(struct request_queue
*q
)
1406 struct scsi_device
*sdev
= q
->queuedata
;
1407 struct Scsi_Host
*shost
;
1408 struct scsi_cmnd
*cmd
;
1409 struct request
*req
;
1412 printk("scsi: killing requests for dead queue\n");
1413 while ((req
= elv_next_request(q
)) != NULL
)
1414 scsi_kill_request(req
, q
);
1418 if(!get_device(&sdev
->sdev_gendev
))
1419 /* We must be tearing the block queue down already */
1423 * To start with, we keep looping until the queue is empty, or until
1424 * the host is no longer able to accept any more requests.
1427 while (!blk_queue_plugged(q
)) {
1430 * get next queueable request. We do this early to make sure
1431 * that the request is fully prepared even if we cannot
1434 req
= elv_next_request(q
);
1435 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1438 if (unlikely(!scsi_device_online(sdev
))) {
1439 sdev_printk(KERN_ERR
, sdev
,
1440 "rejecting I/O to offline device\n");
1441 scsi_kill_request(req
, q
);
1447 * Remove the request from the request list.
1449 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1450 blkdev_dequeue_request(req
);
1451 sdev
->device_busy
++;
1453 spin_unlock(q
->queue_lock
);
1455 if (unlikely(cmd
== NULL
)) {
1456 printk(KERN_CRIT
"impossible request in %s.\n"
1457 "please mail a stack trace to "
1458 "linux-scsi@vger.kernel.org\n",
1460 blk_dump_rq_flags(req
, "foo");
1463 spin_lock(shost
->host_lock
);
1465 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1467 if (sdev
->single_lun
) {
1468 if (scsi_target(sdev
)->starget_sdev_user
&&
1469 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1471 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1476 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1477 * take the lock again.
1479 spin_unlock_irq(shost
->host_lock
);
1482 * Finally, initialize any error handling parameters, and set up
1483 * the timers for timeouts.
1485 scsi_init_cmd_errh(cmd
);
1488 * Dispatch the command to the low-level driver.
1490 rtn
= scsi_dispatch_cmd(cmd
);
1491 spin_lock_irq(q
->queue_lock
);
1493 /* we're refusing the command; because of
1494 * the way locks get dropped, we need to
1495 * check here if plugging is required */
1496 if(sdev
->device_busy
== 0)
1506 spin_unlock_irq(shost
->host_lock
);
1509 * lock q, handle tag, requeue req, and decrement device_busy. We
1510 * must return with queue_lock held.
1512 * Decrementing device_busy without checking it is OK, as all such
1513 * cases (host limits or settings) should run the queue at some
1516 spin_lock_irq(q
->queue_lock
);
1517 blk_requeue_request(q
, req
);
1518 sdev
->device_busy
--;
1519 if(sdev
->device_busy
== 0)
1522 /* must be careful here...if we trigger the ->remove() function
1523 * we cannot be holding the q lock */
1524 spin_unlock_irq(q
->queue_lock
);
1525 put_device(&sdev
->sdev_gendev
);
1526 spin_lock_irq(q
->queue_lock
);
1529 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1531 struct device
*host_dev
;
1532 u64 bounce_limit
= 0xffffffff;
1534 if (shost
->unchecked_isa_dma
)
1535 return BLK_BOUNCE_ISA
;
1537 * Platforms with virtual-DMA translation
1538 * hardware have no practical limit.
1540 if (!PCI_DMA_BUS_IS_PHYS
)
1541 return BLK_BOUNCE_ANY
;
1543 host_dev
= scsi_get_device(shost
);
1544 if (host_dev
&& host_dev
->dma_mask
)
1545 bounce_limit
= *host_dev
->dma_mask
;
1547 return bounce_limit
;
1549 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1551 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1553 struct Scsi_Host
*shost
= sdev
->host
;
1554 struct request_queue
*q
;
1556 q
= blk_init_queue(scsi_request_fn
, NULL
);
1560 blk_queue_prep_rq(q
, scsi_prep_fn
);
1562 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1563 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1564 blk_queue_max_sectors(q
, shost
->max_sectors
);
1565 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1566 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1567 blk_queue_issue_flush_fn(q
, scsi_issue_flush_fn
);
1568 blk_queue_softirq_done(q
, scsi_softirq_done
);
1570 if (!shost
->use_clustering
)
1571 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1575 void scsi_free_queue(struct request_queue
*q
)
1577 blk_cleanup_queue(q
);
1581 * Function: scsi_block_requests()
1583 * Purpose: Utility function used by low-level drivers to prevent further
1584 * commands from being queued to the device.
1586 * Arguments: shost - Host in question
1590 * Lock status: No locks are assumed held.
1592 * Notes: There is no timer nor any other means by which the requests
1593 * get unblocked other than the low-level driver calling
1594 * scsi_unblock_requests().
1596 void scsi_block_requests(struct Scsi_Host
*shost
)
1598 shost
->host_self_blocked
= 1;
1600 EXPORT_SYMBOL(scsi_block_requests
);
1603 * Function: scsi_unblock_requests()
1605 * Purpose: Utility function used by low-level drivers to allow further
1606 * commands from being queued to the device.
1608 * Arguments: shost - Host in question
1612 * Lock status: No locks are assumed held.
1614 * Notes: There is no timer nor any other means by which the requests
1615 * get unblocked other than the low-level driver calling
1616 * scsi_unblock_requests().
1618 * This is done as an API function so that changes to the
1619 * internals of the scsi mid-layer won't require wholesale
1620 * changes to drivers that use this feature.
1622 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1624 shost
->host_self_blocked
= 0;
1625 scsi_run_host_queues(shost
);
1627 EXPORT_SYMBOL(scsi_unblock_requests
);
1629 int __init
scsi_init_queue(void)
1633 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1634 sizeof(struct scsi_io_context
),
1636 if (!scsi_io_context_cache
) {
1637 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1641 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1642 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1643 int size
= sgp
->size
* sizeof(struct scatterlist
);
1645 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1646 SLAB_HWCACHE_ALIGN
, NULL
, NULL
);
1648 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1652 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1655 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1663 void scsi_exit_queue(void)
1667 kmem_cache_destroy(scsi_io_context_cache
);
1669 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1670 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1671 mempool_destroy(sgp
->pool
);
1672 kmem_cache_destroy(sgp
->slab
);
1677 * scsi_mode_select - issue a mode select
1678 * @sdev: SCSI device to be queried
1679 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1680 * @sp: Save page bit (0 == don't save, 1 == save)
1681 * @modepage: mode page being requested
1682 * @buffer: request buffer (may not be smaller than eight bytes)
1683 * @len: length of request buffer.
1684 * @timeout: command timeout
1685 * @retries: number of retries before failing
1686 * @data: returns a structure abstracting the mode header data
1687 * @sense: place to put sense data (or NULL if no sense to be collected).
1688 * must be SCSI_SENSE_BUFFERSIZE big.
1690 * Returns zero if successful; negative error number or scsi
1695 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1696 unsigned char *buffer
, int len
, int timeout
, int retries
,
1697 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1699 unsigned char cmd
[10];
1700 unsigned char *real_buffer
;
1703 memset(cmd
, 0, sizeof(cmd
));
1704 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1706 if (sdev
->use_10_for_ms
) {
1709 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1712 memcpy(real_buffer
+ 8, buffer
, len
);
1716 real_buffer
[2] = data
->medium_type
;
1717 real_buffer
[3] = data
->device_specific
;
1718 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1720 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1721 real_buffer
[7] = data
->block_descriptor_length
;
1723 cmd
[0] = MODE_SELECT_10
;
1727 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1731 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1734 memcpy(real_buffer
+ 4, buffer
, len
);
1737 real_buffer
[1] = data
->medium_type
;
1738 real_buffer
[2] = data
->device_specific
;
1739 real_buffer
[3] = data
->block_descriptor_length
;
1742 cmd
[0] = MODE_SELECT
;
1746 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1747 sshdr
, timeout
, retries
);
1751 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1754 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1755 * six bytes if necessary.
1756 * @sdev: SCSI device to be queried
1757 * @dbd: set if mode sense will allow block descriptors to be returned
1758 * @modepage: mode page being requested
1759 * @buffer: request buffer (may not be smaller than eight bytes)
1760 * @len: length of request buffer.
1761 * @timeout: command timeout
1762 * @retries: number of retries before failing
1763 * @data: returns a structure abstracting the mode header data
1764 * @sense: place to put sense data (or NULL if no sense to be collected).
1765 * must be SCSI_SENSE_BUFFERSIZE big.
1767 * Returns zero if unsuccessful, or the header offset (either 4
1768 * or 8 depending on whether a six or ten byte command was
1769 * issued) if successful.
1772 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1773 unsigned char *buffer
, int len
, int timeout
, int retries
,
1774 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1776 unsigned char cmd
[12];
1780 struct scsi_sense_hdr my_sshdr
;
1782 memset(data
, 0, sizeof(*data
));
1783 memset(&cmd
[0], 0, 12);
1784 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1787 /* caller might not be interested in sense, but we need it */
1792 use_10_for_ms
= sdev
->use_10_for_ms
;
1794 if (use_10_for_ms
) {
1798 cmd
[0] = MODE_SENSE_10
;
1805 cmd
[0] = MODE_SENSE
;
1810 memset(buffer
, 0, len
);
1812 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1813 sshdr
, timeout
, retries
);
1815 /* This code looks awful: what it's doing is making sure an
1816 * ILLEGAL REQUEST sense return identifies the actual command
1817 * byte as the problem. MODE_SENSE commands can return
1818 * ILLEGAL REQUEST if the code page isn't supported */
1820 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1821 (driver_byte(result
) & DRIVER_SENSE
)) {
1822 if (scsi_sense_valid(sshdr
)) {
1823 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1824 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1826 * Invalid command operation code
1828 sdev
->use_10_for_ms
= 0;
1834 if(scsi_status_is_good(result
)) {
1835 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1836 (modepage
== 6 || modepage
== 8))) {
1837 /* Initio breakage? */
1840 data
->medium_type
= 0;
1841 data
->device_specific
= 0;
1843 data
->block_descriptor_length
= 0;
1844 } else if(use_10_for_ms
) {
1845 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1846 data
->medium_type
= buffer
[2];
1847 data
->device_specific
= buffer
[3];
1848 data
->longlba
= buffer
[4] & 0x01;
1849 data
->block_descriptor_length
= buffer
[6]*256
1852 data
->length
= buffer
[0] + 1;
1853 data
->medium_type
= buffer
[1];
1854 data
->device_specific
= buffer
[2];
1855 data
->block_descriptor_length
= buffer
[3];
1857 data
->header_length
= header_length
;
1862 EXPORT_SYMBOL(scsi_mode_sense
);
1865 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1868 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1870 struct scsi_sense_hdr sshdr
;
1873 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1876 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1878 if ((scsi_sense_valid(&sshdr
)) &&
1879 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1880 (sshdr
.sense_key
== NOT_READY
))) {
1887 EXPORT_SYMBOL(scsi_test_unit_ready
);
1890 * scsi_device_set_state - Take the given device through the device
1892 * @sdev: scsi device to change the state of.
1893 * @state: state to change to.
1895 * Returns zero if unsuccessful or an error if the requested
1896 * transition is illegal.
1899 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1901 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1903 if (state
== oldstate
)
1908 /* There are no legal states that come back to
1909 * created. This is the manually initialised start
1983 sdev
->sdev_state
= state
;
1987 SCSI_LOG_ERROR_RECOVERY(1,
1988 sdev_printk(KERN_ERR
, sdev
,
1989 "Illegal state transition %s->%s\n",
1990 scsi_device_state_name(oldstate
),
1991 scsi_device_state_name(state
))
1995 EXPORT_SYMBOL(scsi_device_set_state
);
1998 * scsi_device_quiesce - Block user issued commands.
1999 * @sdev: scsi device to quiesce.
2001 * This works by trying to transition to the SDEV_QUIESCE state
2002 * (which must be a legal transition). When the device is in this
2003 * state, only special requests will be accepted, all others will
2004 * be deferred. Since special requests may also be requeued requests,
2005 * a successful return doesn't guarantee the device will be
2006 * totally quiescent.
2008 * Must be called with user context, may sleep.
2010 * Returns zero if unsuccessful or an error if not.
2013 scsi_device_quiesce(struct scsi_device
*sdev
)
2015 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2019 scsi_run_queue(sdev
->request_queue
);
2020 while (sdev
->device_busy
) {
2021 msleep_interruptible(200);
2022 scsi_run_queue(sdev
->request_queue
);
2026 EXPORT_SYMBOL(scsi_device_quiesce
);
2029 * scsi_device_resume - Restart user issued commands to a quiesced device.
2030 * @sdev: scsi device to resume.
2032 * Moves the device from quiesced back to running and restarts the
2035 * Must be called with user context, may sleep.
2038 scsi_device_resume(struct scsi_device
*sdev
)
2040 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2042 scsi_run_queue(sdev
->request_queue
);
2044 EXPORT_SYMBOL(scsi_device_resume
);
2047 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2049 scsi_device_quiesce(sdev
);
2053 scsi_target_quiesce(struct scsi_target
*starget
)
2055 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2057 EXPORT_SYMBOL(scsi_target_quiesce
);
2060 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2062 scsi_device_resume(sdev
);
2066 scsi_target_resume(struct scsi_target
*starget
)
2068 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2070 EXPORT_SYMBOL(scsi_target_resume
);
2073 * scsi_internal_device_block - internal function to put a device
2074 * temporarily into the SDEV_BLOCK state
2075 * @sdev: device to block
2077 * Block request made by scsi lld's to temporarily stop all
2078 * scsi commands on the specified device. Called from interrupt
2079 * or normal process context.
2081 * Returns zero if successful or error if not
2084 * This routine transitions the device to the SDEV_BLOCK state
2085 * (which must be a legal transition). When the device is in this
2086 * state, all commands are deferred until the scsi lld reenables
2087 * the device with scsi_device_unblock or device_block_tmo fires.
2088 * This routine assumes the host_lock is held on entry.
2091 scsi_internal_device_block(struct scsi_device
*sdev
)
2093 request_queue_t
*q
= sdev
->request_queue
;
2094 unsigned long flags
;
2097 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2102 * The device has transitioned to SDEV_BLOCK. Stop the
2103 * block layer from calling the midlayer with this device's
2106 spin_lock_irqsave(q
->queue_lock
, flags
);
2108 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2112 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2115 * scsi_internal_device_unblock - resume a device after a block request
2116 * @sdev: device to resume
2118 * Called by scsi lld's or the midlayer to restart the device queue
2119 * for the previously suspended scsi device. Called from interrupt or
2120 * normal process context.
2122 * Returns zero if successful or error if not.
2125 * This routine transitions the device to the SDEV_RUNNING state
2126 * (which must be a legal transition) allowing the midlayer to
2127 * goose the queue for this device. This routine assumes the
2128 * host_lock is held upon entry.
2131 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2133 request_queue_t
*q
= sdev
->request_queue
;
2135 unsigned long flags
;
2138 * Try to transition the scsi device to SDEV_RUNNING
2139 * and goose the device queue if successful.
2141 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2145 spin_lock_irqsave(q
->queue_lock
, flags
);
2147 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2151 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2154 device_block(struct scsi_device
*sdev
, void *data
)
2156 scsi_internal_device_block(sdev
);
2160 target_block(struct device
*dev
, void *data
)
2162 if (scsi_is_target_device(dev
))
2163 starget_for_each_device(to_scsi_target(dev
), NULL
,
2169 scsi_target_block(struct device
*dev
)
2171 if (scsi_is_target_device(dev
))
2172 starget_for_each_device(to_scsi_target(dev
), NULL
,
2175 device_for_each_child(dev
, NULL
, target_block
);
2177 EXPORT_SYMBOL_GPL(scsi_target_block
);
2180 device_unblock(struct scsi_device
*sdev
, void *data
)
2182 scsi_internal_device_unblock(sdev
);
2186 target_unblock(struct device
*dev
, void *data
)
2188 if (scsi_is_target_device(dev
))
2189 starget_for_each_device(to_scsi_target(dev
), NULL
,
2195 scsi_target_unblock(struct device
*dev
)
2197 if (scsi_is_target_device(dev
))
2198 starget_for_each_device(to_scsi_target(dev
), NULL
,
2201 device_for_each_child(dev
, NULL
, target_unblock
);
2203 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2206 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2207 * @sg: scatter-gather list
2208 * @sg_count: number of segments in sg
2209 * @offset: offset in bytes into sg, on return offset into the mapped area
2210 * @len: bytes to map, on return number of bytes mapped
2212 * Returns virtual address of the start of the mapped page
2214 void *scsi_kmap_atomic_sg(struct scatterlist
*sg
, int sg_count
,
2215 size_t *offset
, size_t *len
)
2218 size_t sg_len
= 0, len_complete
= 0;
2221 for (i
= 0; i
< sg_count
; i
++) {
2222 len_complete
= sg_len
; /* Complete sg-entries */
2223 sg_len
+= sg
[i
].length
;
2224 if (sg_len
> *offset
)
2228 if (unlikely(i
== sg_count
)) {
2229 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2231 __FUNCTION__
, sg_len
, *offset
, sg_count
);
2236 /* Offset starting from the beginning of first page in this sg-entry */
2237 *offset
= *offset
- len_complete
+ sg
[i
].offset
;
2239 /* Assumption: contiguous pages can be accessed as "page + i" */
2240 page
= nth_page(sg
[i
].page
, (*offset
>> PAGE_SHIFT
));
2241 *offset
&= ~PAGE_MASK
;
2243 /* Bytes in this sg-entry from *offset to the end of the page */
2244 sg_len
= PAGE_SIZE
- *offset
;
2248 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2250 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2253 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2254 * mapped with scsi_kmap_atomic_sg
2255 * @virt: virtual address to be unmapped
2257 void scsi_kunmap_atomic_sg(void *virt
)
2259 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2261 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);