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 2
36 struct scsi_host_sg_pool
{
39 struct kmem_cache
*slab
;
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 scsi_cmnd result
179 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
180 int data_direction
, void *buffer
, unsigned bufflen
,
181 unsigned char *sense
, int timeout
, int retries
, int flags
)
184 int write
= (data_direction
== DMA_TO_DEVICE
);
185 int ret
= DRIVER_ERROR
<< 24;
187 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
189 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
190 buffer
, bufflen
, __GFP_WAIT
))
193 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
194 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
197 req
->retries
= retries
;
198 req
->timeout
= timeout
;
199 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
200 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
203 * head injection *required* here otherwise quiesce won't work
205 blk_execute_rq(req
->q
, NULL
, req
, 1);
209 blk_put_request(req
);
213 EXPORT_SYMBOL(scsi_execute
);
216 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
217 int data_direction
, void *buffer
, unsigned bufflen
,
218 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
224 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
226 return DRIVER_ERROR
<< 24;
228 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
229 sense
, timeout
, retries
, 0);
231 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
236 EXPORT_SYMBOL(scsi_execute_req
);
238 struct scsi_io_context
{
240 void (*done
)(void *data
, char *sense
, int result
, int resid
);
241 char sense
[SCSI_SENSE_BUFFERSIZE
];
244 static struct kmem_cache
*scsi_io_context_cache
;
246 static void scsi_end_async(struct request
*req
, int uptodate
)
248 struct scsi_io_context
*sioc
= req
->end_io_data
;
251 sioc
->done(sioc
->data
, sioc
->sense
, req
->errors
, req
->data_len
);
253 kmem_cache_free(scsi_io_context_cache
, sioc
);
254 __blk_put_request(req
->q
, req
);
257 static int scsi_merge_bio(struct request
*rq
, struct bio
*bio
)
259 struct request_queue
*q
= rq
->q
;
261 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
262 if (rq_data_dir(rq
) == WRITE
)
263 bio
->bi_rw
|= (1 << BIO_RW
);
264 blk_queue_bounce(q
, &bio
);
267 blk_rq_bio_prep(q
, rq
, bio
);
268 else if (!ll_back_merge_fn(q
, rq
, bio
))
271 rq
->biotail
->bi_next
= bio
;
278 static int scsi_bi_endio(struct bio
*bio
, unsigned int bytes_done
, int error
)
288 * scsi_req_map_sg - map a scatterlist into a request
289 * @rq: request to fill
291 * @nsegs: number of elements
292 * @bufflen: len of buffer
293 * @gfp: memory allocation flags
295 * scsi_req_map_sg maps a scatterlist into a request so that the
296 * request can be sent to the block layer. We do not trust the scatterlist
297 * sent to use, as some ULDs use that struct to only organize the pages.
299 static int scsi_req_map_sg(struct request
*rq
, struct scatterlist
*sgl
,
300 int nsegs
, unsigned bufflen
, gfp_t gfp
)
302 struct request_queue
*q
= rq
->q
;
303 int nr_pages
= (bufflen
+ sgl
[0].offset
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
304 unsigned int data_len
= bufflen
, len
, bytes
, off
;
306 struct bio
*bio
= NULL
;
307 int i
, err
, nr_vecs
= 0;
309 for (i
= 0; i
< nsegs
; i
++) {
314 while (len
> 0 && data_len
> 0) {
316 * sg sends a scatterlist that is larger than
317 * the data_len it wants transferred for certain
320 bytes
= min_t(unsigned int, len
, PAGE_SIZE
- off
);
321 bytes
= min(bytes
, data_len
);
324 nr_vecs
= min_t(int, BIO_MAX_PAGES
, nr_pages
);
327 bio
= bio_alloc(gfp
, nr_vecs
);
332 bio
->bi_end_io
= scsi_bi_endio
;
335 if (bio_add_pc_page(q
, bio
, page
, bytes
, off
) !=
342 if (bio
->bi_vcnt
>= nr_vecs
) {
343 err
= scsi_merge_bio(rq
, bio
);
345 bio_endio(bio
, bio
->bi_size
, 0);
358 rq
->buffer
= rq
->data
= NULL
;
359 rq
->data_len
= bufflen
;
363 while ((bio
= rq
->bio
) != NULL
) {
364 rq
->bio
= bio
->bi_next
;
366 * call endio instead of bio_put incase it was bounced
368 bio_endio(bio
, bio
->bi_size
, 0);
375 * scsi_execute_async - insert request
378 * @cmd_len: length of scsi cdb
379 * @data_direction: data direction
380 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
381 * @bufflen: len of buffer
382 * @use_sg: if buffer is a scatterlist this is the number of elements
383 * @timeout: request timeout in seconds
384 * @retries: number of times to retry request
385 * @flags: or into request flags
387 int scsi_execute_async(struct scsi_device
*sdev
, const unsigned char *cmd
,
388 int cmd_len
, int data_direction
, void *buffer
, unsigned bufflen
,
389 int use_sg
, int timeout
, int retries
, void *privdata
,
390 void (*done
)(void *, char *, int, int), gfp_t gfp
)
393 struct scsi_io_context
*sioc
;
395 int write
= (data_direction
== DMA_TO_DEVICE
);
397 sioc
= kmem_cache_zalloc(scsi_io_context_cache
, gfp
);
399 return DRIVER_ERROR
<< 24;
401 req
= blk_get_request(sdev
->request_queue
, write
, gfp
);
404 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
405 req
->cmd_flags
|= REQ_QUIET
;
408 err
= scsi_req_map_sg(req
, buffer
, use_sg
, bufflen
, gfp
);
410 err
= blk_rq_map_kern(req
->q
, req
, buffer
, bufflen
, gfp
);
415 req
->cmd_len
= cmd_len
;
416 memset(req
->cmd
, 0, BLK_MAX_CDB
); /* ATAPI hates garbage after CDB */
417 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
418 req
->sense
= sioc
->sense
;
420 req
->timeout
= timeout
;
421 req
->retries
= retries
;
422 req
->end_io_data
= sioc
;
424 sioc
->data
= privdata
;
427 blk_execute_rq_nowait(req
->q
, NULL
, req
, 1, scsi_end_async
);
431 blk_put_request(req
);
433 kmem_cache_free(scsi_io_context_cache
, sioc
);
434 return DRIVER_ERROR
<< 24;
436 EXPORT_SYMBOL_GPL(scsi_execute_async
);
439 * Function: scsi_init_cmd_errh()
441 * Purpose: Initialize cmd fields related to error handling.
443 * Arguments: cmd - command that is ready to be queued.
445 * Notes: This function has the job of initializing a number of
446 * fields related to error handling. Typically this will
447 * be called once for each command, as required.
449 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
451 cmd
->serial_number
= 0;
453 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
454 if (cmd
->cmd_len
== 0)
455 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
458 void scsi_device_unbusy(struct scsi_device
*sdev
)
460 struct Scsi_Host
*shost
= sdev
->host
;
463 spin_lock_irqsave(shost
->host_lock
, flags
);
465 if (unlikely(scsi_host_in_recovery(shost
) &&
466 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
467 scsi_eh_wakeup(shost
);
468 spin_unlock(shost
->host_lock
);
469 spin_lock(sdev
->request_queue
->queue_lock
);
471 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
475 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
476 * and call blk_run_queue for all the scsi_devices on the target -
477 * including current_sdev first.
479 * Called with *no* scsi locks held.
481 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
483 struct Scsi_Host
*shost
= current_sdev
->host
;
484 struct scsi_device
*sdev
, *tmp
;
485 struct scsi_target
*starget
= scsi_target(current_sdev
);
488 spin_lock_irqsave(shost
->host_lock
, flags
);
489 starget
->starget_sdev_user
= NULL
;
490 spin_unlock_irqrestore(shost
->host_lock
, flags
);
493 * Call blk_run_queue for all LUNs on the target, starting with
494 * current_sdev. We race with others (to set starget_sdev_user),
495 * but in most cases, we will be first. Ideally, each LU on the
496 * target would get some limited time or requests on the target.
498 blk_run_queue(current_sdev
->request_queue
);
500 spin_lock_irqsave(shost
->host_lock
, flags
);
501 if (starget
->starget_sdev_user
)
503 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
504 same_target_siblings
) {
505 if (sdev
== current_sdev
)
507 if (scsi_device_get(sdev
))
510 spin_unlock_irqrestore(shost
->host_lock
, flags
);
511 blk_run_queue(sdev
->request_queue
);
512 spin_lock_irqsave(shost
->host_lock
, flags
);
514 scsi_device_put(sdev
);
517 spin_unlock_irqrestore(shost
->host_lock
, flags
);
521 * Function: scsi_run_queue()
523 * Purpose: Select a proper request queue to serve next
525 * Arguments: q - last request's queue
529 * Notes: The previous command was completely finished, start
530 * a new one if possible.
532 static void scsi_run_queue(struct request_queue
*q
)
534 struct scsi_device
*sdev
= q
->queuedata
;
535 struct Scsi_Host
*shost
= sdev
->host
;
538 if (sdev
->single_lun
)
539 scsi_single_lun_run(sdev
);
541 spin_lock_irqsave(shost
->host_lock
, flags
);
542 while (!list_empty(&shost
->starved_list
) &&
543 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
544 !((shost
->can_queue
> 0) &&
545 (shost
->host_busy
>= shost
->can_queue
))) {
547 * As long as shost is accepting commands and we have
548 * starved queues, call blk_run_queue. scsi_request_fn
549 * drops the queue_lock and can add us back to the
552 * host_lock protects the starved_list and starved_entry.
553 * scsi_request_fn must get the host_lock before checking
554 * or modifying starved_list or starved_entry.
556 sdev
= list_entry(shost
->starved_list
.next
,
557 struct scsi_device
, starved_entry
);
558 list_del_init(&sdev
->starved_entry
);
559 spin_unlock_irqrestore(shost
->host_lock
, flags
);
562 if (test_bit(QUEUE_FLAG_REENTER
, &q
->queue_flags
) &&
563 !test_and_set_bit(QUEUE_FLAG_REENTER
,
564 &sdev
->request_queue
->queue_flags
)) {
565 blk_run_queue(sdev
->request_queue
);
566 clear_bit(QUEUE_FLAG_REENTER
,
567 &sdev
->request_queue
->queue_flags
);
569 blk_run_queue(sdev
->request_queue
);
571 spin_lock_irqsave(shost
->host_lock
, flags
);
572 if (unlikely(!list_empty(&sdev
->starved_entry
)))
574 * sdev lost a race, and was put back on the
575 * starved list. This is unlikely but without this
576 * in theory we could loop forever.
580 spin_unlock_irqrestore(shost
->host_lock
, flags
);
586 * Function: scsi_requeue_command()
588 * Purpose: Handle post-processing of completed commands.
590 * Arguments: q - queue to operate on
591 * cmd - command that may need to be requeued.
595 * Notes: After command completion, there may be blocks left
596 * over which weren't finished by the previous command
597 * this can be for a number of reasons - the main one is
598 * I/O errors in the middle of the request, in which case
599 * we need to request the blocks that come after the bad
601 * Notes: Upon return, cmd is a stale pointer.
603 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
605 struct request
*req
= cmd
->request
;
608 scsi_unprep_request(req
);
609 spin_lock_irqsave(q
->queue_lock
, flags
);
610 blk_requeue_request(q
, req
);
611 spin_unlock_irqrestore(q
->queue_lock
, flags
);
616 void scsi_next_command(struct scsi_cmnd
*cmd
)
618 struct scsi_device
*sdev
= cmd
->device
;
619 struct request_queue
*q
= sdev
->request_queue
;
621 /* need to hold a reference on the device before we let go of the cmd */
622 get_device(&sdev
->sdev_gendev
);
624 scsi_put_command(cmd
);
627 /* ok to remove device now */
628 put_device(&sdev
->sdev_gendev
);
631 void scsi_run_host_queues(struct Scsi_Host
*shost
)
633 struct scsi_device
*sdev
;
635 shost_for_each_device(sdev
, shost
)
636 scsi_run_queue(sdev
->request_queue
);
640 * Function: scsi_end_request()
642 * Purpose: Post-processing of completed commands (usually invoked at end
643 * of upper level post-processing and scsi_io_completion).
645 * Arguments: cmd - command that is complete.
646 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
647 * bytes - number of bytes of completed I/O
648 * requeue - indicates whether we should requeue leftovers.
650 * Lock status: Assumed that lock is not held upon entry.
652 * Returns: cmd if requeue required, NULL otherwise.
654 * Notes: This is called for block device requests in order to
655 * mark some number of sectors as complete.
657 * We are guaranteeing that the request queue will be goosed
658 * at some point during this call.
659 * Notes: If cmd was requeued, upon return it will be a stale pointer.
661 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
662 int bytes
, int requeue
)
664 struct request_queue
*q
= cmd
->device
->request_queue
;
665 struct request
*req
= cmd
->request
;
669 * If there are blocks left over at the end, set up the command
670 * to queue the remainder of them.
672 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
673 int leftover
= (req
->hard_nr_sectors
<< 9);
675 if (blk_pc_request(req
))
676 leftover
= req
->data_len
;
678 /* kill remainder if no retrys */
679 if (!uptodate
&& blk_noretry_request(req
))
680 end_that_request_chunk(req
, 0, leftover
);
684 * Bleah. Leftovers again. Stick the
685 * leftovers in the front of the
686 * queue, and goose the queue again.
688 scsi_requeue_command(q
, cmd
);
695 add_disk_randomness(req
->rq_disk
);
697 spin_lock_irqsave(q
->queue_lock
, flags
);
698 if (blk_rq_tagged(req
))
699 blk_queue_end_tag(q
, req
);
700 end_that_request_last(req
, uptodate
);
701 spin_unlock_irqrestore(q
->queue_lock
, flags
);
704 * This will goose the queue request function at the end, so we don't
705 * need to worry about launching another command.
707 scsi_next_command(cmd
);
711 struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
713 struct scsi_host_sg_pool
*sgp
;
714 struct scatterlist
*sgl
;
716 BUG_ON(!cmd
->use_sg
);
718 switch (cmd
->use_sg
) {
728 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
732 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
736 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
747 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
748 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
752 EXPORT_SYMBOL(scsi_alloc_sgtable
);
754 void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
756 struct scsi_host_sg_pool
*sgp
;
758 BUG_ON(index
>= SG_MEMPOOL_NR
);
760 sgp
= scsi_sg_pools
+ index
;
761 mempool_free(sgl
, sgp
->pool
);
764 EXPORT_SYMBOL(scsi_free_sgtable
);
767 * Function: scsi_release_buffers()
769 * Purpose: Completion processing for block device I/O requests.
771 * Arguments: cmd - command that we are bailing.
773 * Lock status: Assumed that no lock is held upon entry.
777 * Notes: In the event that an upper level driver rejects a
778 * command, we must release resources allocated during
779 * the __init_io() function. Primarily this would involve
780 * the scatter-gather table, and potentially any bounce
783 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
786 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
789 * Zero these out. They now point to freed memory, and it is
790 * dangerous to hang onto the pointers.
792 cmd
->request_buffer
= NULL
;
793 cmd
->request_bufflen
= 0;
797 * Function: scsi_io_completion()
799 * Purpose: Completion processing for block device I/O requests.
801 * Arguments: cmd - command that is finished.
803 * Lock status: Assumed that no lock is held upon entry.
807 * Notes: This function is matched in terms of capabilities to
808 * the function that created the scatter-gather list.
809 * In other words, if there are no bounce buffers
810 * (the normal case for most drivers), we don't need
811 * the logic to deal with cleaning up afterwards.
813 * We must do one of several things here:
815 * a) Call scsi_end_request. This will finish off the
816 * specified number of sectors. If we are done, the
817 * command block will be released, and the queue
818 * function will be goosed. If we are not done, then
819 * scsi_end_request will directly goose the queue.
821 * b) We can just use scsi_requeue_command() here. This would
822 * be used if we just wanted to retry, for example.
824 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
826 int result
= cmd
->result
;
827 int this_count
= cmd
->request_bufflen
;
828 struct request_queue
*q
= cmd
->device
->request_queue
;
829 struct request
*req
= cmd
->request
;
830 int clear_errors
= 1;
831 struct scsi_sense_hdr sshdr
;
833 int sense_deferred
= 0;
835 scsi_release_buffers(cmd
);
838 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
840 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
843 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
844 req
->errors
= result
;
847 if (sense_valid
&& req
->sense
) {
849 * SG_IO wants current and deferred errors
851 int len
= 8 + cmd
->sense_buffer
[7];
853 if (len
> SCSI_SENSE_BUFFERSIZE
)
854 len
= SCSI_SENSE_BUFFERSIZE
;
855 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
856 req
->sense_len
= len
;
859 req
->data_len
= cmd
->resid
;
863 * Next deal with any sectors which we were able to correctly
866 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
868 req
->nr_sectors
, good_bytes
));
869 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
874 /* A number of bytes were successfully read. If there
875 * are leftovers and there is some kind of error
876 * (result != 0), retry the rest.
878 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
881 /* good_bytes = 0, or (inclusive) there were leftovers and
882 * result = 0, so scsi_end_request couldn't retry.
884 if (sense_valid
&& !sense_deferred
) {
885 switch (sshdr
.sense_key
) {
887 if (cmd
->device
->removable
) {
888 /* Detected disc change. Set a bit
889 * and quietly refuse further access.
891 cmd
->device
->changed
= 1;
892 scsi_end_request(cmd
, 0, this_count
, 1);
895 /* Must have been a power glitch, or a
896 * bus reset. Could not have been a
897 * media change, so we just retry the
898 * request and see what happens.
900 scsi_requeue_command(q
, cmd
);
904 case ILLEGAL_REQUEST
:
905 /* If we had an ILLEGAL REQUEST returned, then
906 * we may have performed an unsupported
907 * command. The only thing this should be
908 * would be a ten byte read where only a six
909 * byte read was supported. Also, on a system
910 * where READ CAPACITY failed, we may have
911 * read past the end of the disk.
913 if ((cmd
->device
->use_10_for_rw
&&
914 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
915 (cmd
->cmnd
[0] == READ_10
||
916 cmd
->cmnd
[0] == WRITE_10
)) {
917 cmd
->device
->use_10_for_rw
= 0;
918 /* This will cause a retry with a
921 scsi_requeue_command(q
, cmd
);
924 scsi_end_request(cmd
, 0, this_count
, 1);
929 /* If the device is in the process of becoming
930 * ready, or has a temporary blockage, retry.
932 if (sshdr
.asc
== 0x04) {
933 switch (sshdr
.ascq
) {
934 case 0x01: /* becoming ready */
935 case 0x04: /* format in progress */
936 case 0x05: /* rebuild in progress */
937 case 0x06: /* recalculation in progress */
938 case 0x07: /* operation in progress */
939 case 0x08: /* Long write in progress */
940 case 0x09: /* self test in progress */
941 scsi_requeue_command(q
, cmd
);
947 if (!(req
->cmd_flags
& REQ_QUIET
))
948 scsi_cmd_print_sense_hdr(cmd
,
952 scsi_end_request(cmd
, 0, this_count
, 1);
954 case VOLUME_OVERFLOW
:
955 if (!(req
->cmd_flags
& REQ_QUIET
)) {
956 scmd_printk(KERN_INFO
, cmd
,
957 "Volume overflow, CDB: ");
958 __scsi_print_command(cmd
->cmnd
);
959 scsi_print_sense("", cmd
);
961 /* See SSC3rXX or current. */
962 scsi_end_request(cmd
, 0, this_count
, 1);
968 if (host_byte(result
) == DID_RESET
) {
969 /* Third party bus reset or reset for error recovery
970 * reasons. Just retry the request and see what
973 scsi_requeue_command(q
, cmd
);
977 if (!(req
->cmd_flags
& REQ_QUIET
)) {
978 scsi_print_result(cmd
);
979 if (driver_byte(result
) & DRIVER_SENSE
)
980 scsi_print_sense("", cmd
);
983 scsi_end_request(cmd
, 0, this_count
, !result
);
987 * Function: scsi_init_io()
989 * Purpose: SCSI I/O initialize function.
991 * Arguments: cmd - Command descriptor we wish to initialize
993 * Returns: 0 on success
994 * BLKPREP_DEFER if the failure is retryable
995 * BLKPREP_KILL if the failure is fatal
997 static int scsi_init_io(struct scsi_cmnd
*cmd
)
999 struct request
*req
= cmd
->request
;
1000 struct scatterlist
*sgpnt
;
1004 * We used to not use scatter-gather for single segment request,
1005 * but now we do (it makes highmem I/O easier to support without
1008 cmd
->use_sg
= req
->nr_phys_segments
;
1011 * If sg table allocation fails, requeue request later.
1013 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
1014 if (unlikely(!sgpnt
)) {
1015 scsi_unprep_request(req
);
1016 return BLKPREP_DEFER
;
1020 cmd
->request_buffer
= (char *) sgpnt
;
1021 if (blk_pc_request(req
))
1022 cmd
->request_bufflen
= req
->data_len
;
1024 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1027 * Next, walk the list, and fill in the addresses and sizes of
1030 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1031 if (likely(count
<= cmd
->use_sg
)) {
1032 cmd
->use_sg
= count
;
1036 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1037 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1038 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1039 req
->current_nr_sectors
);
1041 return BLKPREP_KILL
;
1044 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1045 struct request
*req
)
1047 struct scsi_cmnd
*cmd
;
1049 if (!req
->special
) {
1050 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1058 /* pull a tag out of the request if we have one */
1059 cmd
->tag
= req
->tag
;
1065 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1067 struct scsi_cmnd
*cmd
;
1068 int ret
= scsi_prep_state_check(sdev
, req
);
1070 if (ret
!= BLKPREP_OK
)
1073 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1075 return BLKPREP_DEFER
;
1078 * BLOCK_PC requests may transfer data, in which case they must
1079 * a bio attached to them. Or they might contain a SCSI command
1080 * that does not transfer data, in which case they may optionally
1081 * submit a request without an attached bio.
1086 BUG_ON(!req
->nr_phys_segments
);
1088 ret
= scsi_init_io(cmd
);
1092 BUG_ON(req
->data_len
);
1095 cmd
->request_bufflen
= 0;
1096 cmd
->request_buffer
= NULL
;
1101 BUILD_BUG_ON(sizeof(req
->cmd
) > sizeof(cmd
->cmnd
));
1102 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1103 cmd
->cmd_len
= req
->cmd_len
;
1105 cmd
->sc_data_direction
= DMA_NONE
;
1106 else if (rq_data_dir(req
) == WRITE
)
1107 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1109 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1111 cmd
->transfersize
= req
->data_len
;
1112 cmd
->allowed
= req
->retries
;
1113 cmd
->timeout_per_command
= req
->timeout
;
1116 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1119 * Setup a REQ_TYPE_FS command. These are simple read/write request
1120 * from filesystems that still need to be translated to SCSI CDBs from
1123 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1125 struct scsi_cmnd
*cmd
;
1126 int ret
= scsi_prep_state_check(sdev
, req
);
1128 if (ret
!= BLKPREP_OK
)
1131 * Filesystem requests must transfer data.
1133 BUG_ON(!req
->nr_phys_segments
);
1135 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1137 return BLKPREP_DEFER
;
1139 return scsi_init_io(cmd
);
1141 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1143 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1145 int ret
= BLKPREP_OK
;
1148 * If the device is not in running state we will reject some
1151 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1152 switch (sdev
->sdev_state
) {
1155 * If the device is offline we refuse to process any
1156 * commands. The device must be brought online
1157 * before trying any recovery commands.
1159 sdev_printk(KERN_ERR
, sdev
,
1160 "rejecting I/O to offline device\n");
1165 * If the device is fully deleted, we refuse to
1166 * process any commands as well.
1168 sdev_printk(KERN_ERR
, sdev
,
1169 "rejecting I/O to dead device\n");
1175 * If the devices is blocked we defer normal commands.
1177 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1178 ret
= BLKPREP_DEFER
;
1182 * For any other not fully online state we only allow
1183 * special commands. In particular any user initiated
1184 * command is not allowed.
1186 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1193 EXPORT_SYMBOL(scsi_prep_state_check
);
1195 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1197 struct scsi_device
*sdev
= q
->queuedata
;
1201 req
->errors
= DID_NO_CONNECT
<< 16;
1202 /* release the command and kill it */
1204 struct scsi_cmnd
*cmd
= req
->special
;
1205 scsi_release_buffers(cmd
);
1206 scsi_put_command(cmd
);
1207 req
->special
= NULL
;
1212 * If we defer, the elv_next_request() returns NULL, but the
1213 * queue must be restarted, so we plug here if no returning
1214 * command will automatically do that.
1216 if (sdev
->device_busy
== 0)
1220 req
->cmd_flags
|= REQ_DONTPREP
;
1225 EXPORT_SYMBOL(scsi_prep_return
);
1227 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1229 struct scsi_device
*sdev
= q
->queuedata
;
1230 int ret
= BLKPREP_KILL
;
1232 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1233 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1234 return scsi_prep_return(q
, req
, ret
);
1238 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1241 * Called with the queue_lock held.
1243 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1244 struct scsi_device
*sdev
)
1246 if (sdev
->device_busy
>= sdev
->queue_depth
)
1248 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1250 * unblock after device_blocked iterates to zero
1252 if (--sdev
->device_blocked
== 0) {
1254 sdev_printk(KERN_INFO
, sdev
,
1255 "unblocking device at zero depth\n"));
1261 if (sdev
->device_blocked
)
1268 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1269 * return 0. We must end up running the queue again whenever 0 is
1270 * returned, else IO can hang.
1272 * Called with host_lock held.
1274 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1275 struct Scsi_Host
*shost
,
1276 struct scsi_device
*sdev
)
1278 if (scsi_host_in_recovery(shost
))
1280 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1282 * unblock after host_blocked iterates to zero
1284 if (--shost
->host_blocked
== 0) {
1286 printk("scsi%d unblocking host at zero depth\n",
1293 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1294 shost
->host_blocked
|| shost
->host_self_blocked
) {
1295 if (list_empty(&sdev
->starved_entry
))
1296 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1300 /* We're OK to process the command, so we can't be starved */
1301 if (!list_empty(&sdev
->starved_entry
))
1302 list_del_init(&sdev
->starved_entry
);
1308 * Kill a request for a dead device
1310 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1312 struct scsi_cmnd
*cmd
= req
->special
;
1313 struct scsi_device
*sdev
= cmd
->device
;
1314 struct Scsi_Host
*shost
= sdev
->host
;
1316 blkdev_dequeue_request(req
);
1318 if (unlikely(cmd
== NULL
)) {
1319 printk(KERN_CRIT
"impossible request in %s.\n",
1324 scsi_init_cmd_errh(cmd
);
1325 cmd
->result
= DID_NO_CONNECT
<< 16;
1326 atomic_inc(&cmd
->device
->iorequest_cnt
);
1329 * SCSI request completion path will do scsi_device_unbusy(),
1330 * bump busy counts. To bump the counters, we need to dance
1331 * with the locks as normal issue path does.
1333 sdev
->device_busy
++;
1334 spin_unlock(sdev
->request_queue
->queue_lock
);
1335 spin_lock(shost
->host_lock
);
1337 spin_unlock(shost
->host_lock
);
1338 spin_lock(sdev
->request_queue
->queue_lock
);
1343 static void scsi_softirq_done(struct request
*rq
)
1345 struct scsi_cmnd
*cmd
= rq
->completion_data
;
1346 unsigned long wait_for
= (cmd
->allowed
+ 1) * cmd
->timeout_per_command
;
1349 INIT_LIST_HEAD(&cmd
->eh_entry
);
1351 disposition
= scsi_decide_disposition(cmd
);
1352 if (disposition
!= SUCCESS
&&
1353 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1354 sdev_printk(KERN_ERR
, cmd
->device
,
1355 "timing out command, waited %lus\n",
1357 disposition
= SUCCESS
;
1360 scsi_log_completion(cmd
, disposition
);
1362 switch (disposition
) {
1364 scsi_finish_command(cmd
);
1367 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1369 case ADD_TO_MLQUEUE
:
1370 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1373 if (!scsi_eh_scmd_add(cmd
, 0))
1374 scsi_finish_command(cmd
);
1379 * Function: scsi_request_fn()
1381 * Purpose: Main strategy routine for SCSI.
1383 * Arguments: q - Pointer to actual queue.
1387 * Lock status: IO request lock assumed to be held when called.
1389 static void scsi_request_fn(struct request_queue
*q
)
1391 struct scsi_device
*sdev
= q
->queuedata
;
1392 struct Scsi_Host
*shost
;
1393 struct scsi_cmnd
*cmd
;
1394 struct request
*req
;
1397 printk("scsi: killing requests for dead queue\n");
1398 while ((req
= elv_next_request(q
)) != NULL
)
1399 scsi_kill_request(req
, q
);
1403 if(!get_device(&sdev
->sdev_gendev
))
1404 /* We must be tearing the block queue down already */
1408 * To start with, we keep looping until the queue is empty, or until
1409 * the host is no longer able to accept any more requests.
1412 while (!blk_queue_plugged(q
)) {
1415 * get next queueable request. We do this early to make sure
1416 * that the request is fully prepared even if we cannot
1419 req
= elv_next_request(q
);
1420 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1423 if (unlikely(!scsi_device_online(sdev
))) {
1424 sdev_printk(KERN_ERR
, sdev
,
1425 "rejecting I/O to offline device\n");
1426 scsi_kill_request(req
, q
);
1432 * Remove the request from the request list.
1434 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1435 blkdev_dequeue_request(req
);
1436 sdev
->device_busy
++;
1438 spin_unlock(q
->queue_lock
);
1440 if (unlikely(cmd
== NULL
)) {
1441 printk(KERN_CRIT
"impossible request in %s.\n"
1442 "please mail a stack trace to "
1443 "linux-scsi@vger.kernel.org\n",
1445 blk_dump_rq_flags(req
, "foo");
1448 spin_lock(shost
->host_lock
);
1450 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1452 if (sdev
->single_lun
) {
1453 if (scsi_target(sdev
)->starget_sdev_user
&&
1454 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1456 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1461 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1462 * take the lock again.
1464 spin_unlock_irq(shost
->host_lock
);
1467 * Finally, initialize any error handling parameters, and set up
1468 * the timers for timeouts.
1470 scsi_init_cmd_errh(cmd
);
1473 * Dispatch the command to the low-level driver.
1475 rtn
= scsi_dispatch_cmd(cmd
);
1476 spin_lock_irq(q
->queue_lock
);
1478 /* we're refusing the command; because of
1479 * the way locks get dropped, we need to
1480 * check here if plugging is required */
1481 if(sdev
->device_busy
== 0)
1491 spin_unlock_irq(shost
->host_lock
);
1494 * lock q, handle tag, requeue req, and decrement device_busy. We
1495 * must return with queue_lock held.
1497 * Decrementing device_busy without checking it is OK, as all such
1498 * cases (host limits or settings) should run the queue at some
1501 spin_lock_irq(q
->queue_lock
);
1502 blk_requeue_request(q
, req
);
1503 sdev
->device_busy
--;
1504 if(sdev
->device_busy
== 0)
1507 /* must be careful here...if we trigger the ->remove() function
1508 * we cannot be holding the q lock */
1509 spin_unlock_irq(q
->queue_lock
);
1510 put_device(&sdev
->sdev_gendev
);
1511 spin_lock_irq(q
->queue_lock
);
1514 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1516 struct device
*host_dev
;
1517 u64 bounce_limit
= 0xffffffff;
1519 if (shost
->unchecked_isa_dma
)
1520 return BLK_BOUNCE_ISA
;
1522 * Platforms with virtual-DMA translation
1523 * hardware have no practical limit.
1525 if (!PCI_DMA_BUS_IS_PHYS
)
1526 return BLK_BOUNCE_ANY
;
1528 host_dev
= scsi_get_device(shost
);
1529 if (host_dev
&& host_dev
->dma_mask
)
1530 bounce_limit
= *host_dev
->dma_mask
;
1532 return bounce_limit
;
1534 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1536 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1537 request_fn_proc
*request_fn
)
1539 struct request_queue
*q
;
1541 q
= blk_init_queue(request_fn
, NULL
);
1545 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1546 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1547 blk_queue_max_sectors(q
, shost
->max_sectors
);
1548 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1549 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1551 if (!shost
->use_clustering
)
1552 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1555 EXPORT_SYMBOL(__scsi_alloc_queue
);
1557 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1559 struct request_queue
*q
;
1561 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1565 blk_queue_prep_rq(q
, scsi_prep_fn
);
1566 blk_queue_softirq_done(q
, scsi_softirq_done
);
1570 void scsi_free_queue(struct request_queue
*q
)
1572 blk_cleanup_queue(q
);
1576 * Function: scsi_block_requests()
1578 * Purpose: Utility function used by low-level drivers to prevent further
1579 * commands from being queued to the device.
1581 * Arguments: shost - Host in question
1585 * Lock status: No locks are assumed held.
1587 * Notes: There is no timer nor any other means by which the requests
1588 * get unblocked other than the low-level driver calling
1589 * scsi_unblock_requests().
1591 void scsi_block_requests(struct Scsi_Host
*shost
)
1593 shost
->host_self_blocked
= 1;
1595 EXPORT_SYMBOL(scsi_block_requests
);
1598 * Function: scsi_unblock_requests()
1600 * Purpose: Utility function used by low-level drivers to allow further
1601 * commands from being queued to the device.
1603 * Arguments: shost - Host in question
1607 * Lock status: No locks are assumed held.
1609 * Notes: There is no timer nor any other means by which the requests
1610 * get unblocked other than the low-level driver calling
1611 * scsi_unblock_requests().
1613 * This is done as an API function so that changes to the
1614 * internals of the scsi mid-layer won't require wholesale
1615 * changes to drivers that use this feature.
1617 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1619 shost
->host_self_blocked
= 0;
1620 scsi_run_host_queues(shost
);
1622 EXPORT_SYMBOL(scsi_unblock_requests
);
1624 int __init
scsi_init_queue(void)
1628 scsi_io_context_cache
= kmem_cache_create("scsi_io_context",
1629 sizeof(struct scsi_io_context
),
1631 if (!scsi_io_context_cache
) {
1632 printk(KERN_ERR
"SCSI: can't init scsi io context cache\n");
1636 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1637 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1638 int size
= sgp
->size
* sizeof(struct scatterlist
);
1640 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1641 SLAB_HWCACHE_ALIGN
, NULL
);
1643 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1647 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1650 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1658 void scsi_exit_queue(void)
1662 kmem_cache_destroy(scsi_io_context_cache
);
1664 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1665 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1666 mempool_destroy(sgp
->pool
);
1667 kmem_cache_destroy(sgp
->slab
);
1672 * scsi_mode_select - issue a mode select
1673 * @sdev: SCSI device to be queried
1674 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1675 * @sp: Save page bit (0 == don't save, 1 == save)
1676 * @modepage: mode page being requested
1677 * @buffer: request buffer (may not be smaller than eight bytes)
1678 * @len: length of request buffer.
1679 * @timeout: command timeout
1680 * @retries: number of retries before failing
1681 * @data: returns a structure abstracting the mode header data
1682 * @sense: place to put sense data (or NULL if no sense to be collected).
1683 * must be SCSI_SENSE_BUFFERSIZE big.
1685 * Returns zero if successful; negative error number or scsi
1690 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1691 unsigned char *buffer
, int len
, int timeout
, int retries
,
1692 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1694 unsigned char cmd
[10];
1695 unsigned char *real_buffer
;
1698 memset(cmd
, 0, sizeof(cmd
));
1699 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1701 if (sdev
->use_10_for_ms
) {
1704 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1707 memcpy(real_buffer
+ 8, buffer
, len
);
1711 real_buffer
[2] = data
->medium_type
;
1712 real_buffer
[3] = data
->device_specific
;
1713 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1715 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1716 real_buffer
[7] = data
->block_descriptor_length
;
1718 cmd
[0] = MODE_SELECT_10
;
1722 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1726 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1729 memcpy(real_buffer
+ 4, buffer
, len
);
1732 real_buffer
[1] = data
->medium_type
;
1733 real_buffer
[2] = data
->device_specific
;
1734 real_buffer
[3] = data
->block_descriptor_length
;
1737 cmd
[0] = MODE_SELECT
;
1741 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1742 sshdr
, timeout
, retries
);
1746 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1749 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1750 * six bytes if necessary.
1751 * @sdev: SCSI device to be queried
1752 * @dbd: set if mode sense will allow block descriptors to be returned
1753 * @modepage: mode page being requested
1754 * @buffer: request buffer (may not be smaller than eight bytes)
1755 * @len: length of request buffer.
1756 * @timeout: command timeout
1757 * @retries: number of retries before failing
1758 * @data: returns a structure abstracting the mode header data
1759 * @sense: place to put sense data (or NULL if no sense to be collected).
1760 * must be SCSI_SENSE_BUFFERSIZE big.
1762 * Returns zero if unsuccessful, or the header offset (either 4
1763 * or 8 depending on whether a six or ten byte command was
1764 * issued) if successful.
1767 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1768 unsigned char *buffer
, int len
, int timeout
, int retries
,
1769 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1771 unsigned char cmd
[12];
1775 struct scsi_sense_hdr my_sshdr
;
1777 memset(data
, 0, sizeof(*data
));
1778 memset(&cmd
[0], 0, 12);
1779 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1782 /* caller might not be interested in sense, but we need it */
1787 use_10_for_ms
= sdev
->use_10_for_ms
;
1789 if (use_10_for_ms
) {
1793 cmd
[0] = MODE_SENSE_10
;
1800 cmd
[0] = MODE_SENSE
;
1805 memset(buffer
, 0, len
);
1807 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1808 sshdr
, timeout
, retries
);
1810 /* This code looks awful: what it's doing is making sure an
1811 * ILLEGAL REQUEST sense return identifies the actual command
1812 * byte as the problem. MODE_SENSE commands can return
1813 * ILLEGAL REQUEST if the code page isn't supported */
1815 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1816 (driver_byte(result
) & DRIVER_SENSE
)) {
1817 if (scsi_sense_valid(sshdr
)) {
1818 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1819 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1821 * Invalid command operation code
1823 sdev
->use_10_for_ms
= 0;
1829 if(scsi_status_is_good(result
)) {
1830 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1831 (modepage
== 6 || modepage
== 8))) {
1832 /* Initio breakage? */
1835 data
->medium_type
= 0;
1836 data
->device_specific
= 0;
1838 data
->block_descriptor_length
= 0;
1839 } else if(use_10_for_ms
) {
1840 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1841 data
->medium_type
= buffer
[2];
1842 data
->device_specific
= buffer
[3];
1843 data
->longlba
= buffer
[4] & 0x01;
1844 data
->block_descriptor_length
= buffer
[6]*256
1847 data
->length
= buffer
[0] + 1;
1848 data
->medium_type
= buffer
[1];
1849 data
->device_specific
= buffer
[2];
1850 data
->block_descriptor_length
= buffer
[3];
1852 data
->header_length
= header_length
;
1857 EXPORT_SYMBOL(scsi_mode_sense
);
1860 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1863 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1865 struct scsi_sense_hdr sshdr
;
1868 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1871 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1873 if ((scsi_sense_valid(&sshdr
)) &&
1874 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1875 (sshdr
.sense_key
== NOT_READY
))) {
1882 EXPORT_SYMBOL(scsi_test_unit_ready
);
1885 * scsi_device_set_state - Take the given device through the device
1887 * @sdev: scsi device to change the state of.
1888 * @state: state to change to.
1890 * Returns zero if unsuccessful or an error if the requested
1891 * transition is illegal.
1894 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1896 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1898 if (state
== oldstate
)
1903 /* There are no legal states that come back to
1904 * created. This is the manually initialised start
1978 sdev
->sdev_state
= state
;
1982 SCSI_LOG_ERROR_RECOVERY(1,
1983 sdev_printk(KERN_ERR
, sdev
,
1984 "Illegal state transition %s->%s\n",
1985 scsi_device_state_name(oldstate
),
1986 scsi_device_state_name(state
))
1990 EXPORT_SYMBOL(scsi_device_set_state
);
1993 * scsi_device_quiesce - Block user issued commands.
1994 * @sdev: scsi device to quiesce.
1996 * This works by trying to transition to the SDEV_QUIESCE state
1997 * (which must be a legal transition). When the device is in this
1998 * state, only special requests will be accepted, all others will
1999 * be deferred. Since special requests may also be requeued requests,
2000 * a successful return doesn't guarantee the device will be
2001 * totally quiescent.
2003 * Must be called with user context, may sleep.
2005 * Returns zero if unsuccessful or an error if not.
2008 scsi_device_quiesce(struct scsi_device
*sdev
)
2010 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2014 scsi_run_queue(sdev
->request_queue
);
2015 while (sdev
->device_busy
) {
2016 msleep_interruptible(200);
2017 scsi_run_queue(sdev
->request_queue
);
2021 EXPORT_SYMBOL(scsi_device_quiesce
);
2024 * scsi_device_resume - Restart user issued commands to a quiesced device.
2025 * @sdev: scsi device to resume.
2027 * Moves the device from quiesced back to running and restarts the
2030 * Must be called with user context, may sleep.
2033 scsi_device_resume(struct scsi_device
*sdev
)
2035 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2037 scsi_run_queue(sdev
->request_queue
);
2039 EXPORT_SYMBOL(scsi_device_resume
);
2042 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2044 scsi_device_quiesce(sdev
);
2048 scsi_target_quiesce(struct scsi_target
*starget
)
2050 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2052 EXPORT_SYMBOL(scsi_target_quiesce
);
2055 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2057 scsi_device_resume(sdev
);
2061 scsi_target_resume(struct scsi_target
*starget
)
2063 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2065 EXPORT_SYMBOL(scsi_target_resume
);
2068 * scsi_internal_device_block - internal function to put a device
2069 * temporarily into the SDEV_BLOCK state
2070 * @sdev: device to block
2072 * Block request made by scsi lld's to temporarily stop all
2073 * scsi commands on the specified device. Called from interrupt
2074 * or normal process context.
2076 * Returns zero if successful or error if not
2079 * This routine transitions the device to the SDEV_BLOCK state
2080 * (which must be a legal transition). When the device is in this
2081 * state, all commands are deferred until the scsi lld reenables
2082 * the device with scsi_device_unblock or device_block_tmo fires.
2083 * This routine assumes the host_lock is held on entry.
2086 scsi_internal_device_block(struct scsi_device
*sdev
)
2088 struct request_queue
*q
= sdev
->request_queue
;
2089 unsigned long flags
;
2092 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2097 * The device has transitioned to SDEV_BLOCK. Stop the
2098 * block layer from calling the midlayer with this device's
2101 spin_lock_irqsave(q
->queue_lock
, flags
);
2103 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2107 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2110 * scsi_internal_device_unblock - resume a device after a block request
2111 * @sdev: device to resume
2113 * Called by scsi lld's or the midlayer to restart the device queue
2114 * for the previously suspended scsi device. Called from interrupt or
2115 * normal process context.
2117 * Returns zero if successful or error if not.
2120 * This routine transitions the device to the SDEV_RUNNING state
2121 * (which must be a legal transition) allowing the midlayer to
2122 * goose the queue for this device. This routine assumes the
2123 * host_lock is held upon entry.
2126 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2128 struct request_queue
*q
= sdev
->request_queue
;
2130 unsigned long flags
;
2133 * Try to transition the scsi device to SDEV_RUNNING
2134 * and goose the device queue if successful.
2136 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2140 spin_lock_irqsave(q
->queue_lock
, flags
);
2142 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2146 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2149 device_block(struct scsi_device
*sdev
, void *data
)
2151 scsi_internal_device_block(sdev
);
2155 target_block(struct device
*dev
, void *data
)
2157 if (scsi_is_target_device(dev
))
2158 starget_for_each_device(to_scsi_target(dev
), NULL
,
2164 scsi_target_block(struct device
*dev
)
2166 if (scsi_is_target_device(dev
))
2167 starget_for_each_device(to_scsi_target(dev
), NULL
,
2170 device_for_each_child(dev
, NULL
, target_block
);
2172 EXPORT_SYMBOL_GPL(scsi_target_block
);
2175 device_unblock(struct scsi_device
*sdev
, void *data
)
2177 scsi_internal_device_unblock(sdev
);
2181 target_unblock(struct device
*dev
, void *data
)
2183 if (scsi_is_target_device(dev
))
2184 starget_for_each_device(to_scsi_target(dev
), NULL
,
2190 scsi_target_unblock(struct device
*dev
)
2192 if (scsi_is_target_device(dev
))
2193 starget_for_each_device(to_scsi_target(dev
), NULL
,
2196 device_for_each_child(dev
, NULL
, target_unblock
);
2198 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2201 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2202 * @sg: scatter-gather list
2203 * @sg_count: number of segments in sg
2204 * @offset: offset in bytes into sg, on return offset into the mapped area
2205 * @len: bytes to map, on return number of bytes mapped
2207 * Returns virtual address of the start of the mapped page
2209 void *scsi_kmap_atomic_sg(struct scatterlist
*sg
, int sg_count
,
2210 size_t *offset
, size_t *len
)
2213 size_t sg_len
= 0, len_complete
= 0;
2216 WARN_ON(!irqs_disabled());
2218 for (i
= 0; i
< sg_count
; i
++) {
2219 len_complete
= sg_len
; /* Complete sg-entries */
2220 sg_len
+= sg
[i
].length
;
2221 if (sg_len
> *offset
)
2225 if (unlikely(i
== sg_count
)) {
2226 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2228 __FUNCTION__
, sg_len
, *offset
, sg_count
);
2233 /* Offset starting from the beginning of first page in this sg-entry */
2234 *offset
= *offset
- len_complete
+ sg
[i
].offset
;
2236 /* Assumption: contiguous pages can be accessed as "page + i" */
2237 page
= nth_page(sg
[i
].page
, (*offset
>> PAGE_SHIFT
));
2238 *offset
&= ~PAGE_MASK
;
2240 /* Bytes in this sg-entry from *offset to the end of the page */
2241 sg_len
= PAGE_SIZE
- *offset
;
2245 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2247 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2250 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2251 * mapped with scsi_kmap_atomic_sg
2252 * @virt: virtual address to be unmapped
2254 void scsi_kunmap_atomic_sg(void *virt
)
2256 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2258 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);