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>
20 #include <scsi/scsi.h>
21 #include <scsi/scsi_dbg.h>
22 #include <scsi/scsi_device.h>
23 #include <scsi/scsi_driver.h>
24 #include <scsi/scsi_eh.h>
25 #include <scsi/scsi_host.h>
26 #include <scsi/scsi_request.h>
28 #include "scsi_priv.h"
29 #include "scsi_logging.h"
32 #define SG_MEMPOOL_NR (sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool))
33 #define SG_MEMPOOL_SIZE 32
35 struct scsi_host_sg_pool
{
42 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
43 #error SCSI_MAX_PHYS_SEGMENTS is too small
46 #define SP(x) { x, "sgpool-" #x }
47 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
51 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
53 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
55 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
57 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
58 #error SCSI_MAX_PHYS_SEGMENTS is too large
68 * Function: scsi_insert_special_req()
70 * Purpose: Insert pre-formed request into request queue.
72 * Arguments: sreq - request that is ready to be queued.
73 * at_head - boolean. True if we should insert at head
74 * of queue, false if we should insert at tail.
76 * Lock status: Assumed that lock is not held upon entry.
80 * Notes: This function is called from character device and from
81 * ioctl types of functions where the caller knows exactly
82 * what SCSI command needs to be issued. The idea is that
83 * we merely inject the command into the queue (at the head
84 * for now), and then call the queue request function to actually
87 int scsi_insert_special_req(struct scsi_request
*sreq
, int at_head
)
90 * Because users of this function are apt to reuse requests with no
91 * modification, we have to sanitise the request flags here
93 sreq
->sr_request
->flags
&= ~REQ_DONTPREP
;
94 blk_insert_request(sreq
->sr_device
->request_queue
, sreq
->sr_request
,
99 static void scsi_run_queue(struct request_queue
*q
);
100 static void scsi_release_buffers(struct scsi_cmnd
*cmd
);
103 * Function: scsi_unprep_request()
105 * Purpose: Remove all preparation done for a request, including its
106 * associated scsi_cmnd, so that it can be requeued.
108 * Arguments: req - request to unprepare
110 * Lock status: Assumed that no locks are held upon entry.
114 static void scsi_unprep_request(struct request
*req
)
116 struct scsi_cmnd
*cmd
= req
->special
;
118 req
->flags
&= ~REQ_DONTPREP
;
119 req
->special
= (req
->flags
& REQ_SPECIAL
) ? cmd
->sc_request
: NULL
;
121 scsi_put_command(cmd
);
125 * Function: scsi_queue_insert()
127 * Purpose: Insert a command in the midlevel queue.
129 * Arguments: cmd - command that we are adding to queue.
130 * reason - why we are inserting command to queue.
132 * Lock status: Assumed that lock is not held upon entry.
136 * Notes: We do this for one of two cases. Either the host is busy
137 * and it cannot accept any more commands for the time being,
138 * or the device returned QUEUE_FULL and can accept no more
140 * Notes: This could be called either from an interrupt context or a
141 * normal process context.
143 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
145 struct Scsi_Host
*host
= cmd
->device
->host
;
146 struct scsi_device
*device
= cmd
->device
;
147 struct request_queue
*q
= device
->request_queue
;
151 printk("Inserting command %p into mlqueue\n", cmd
));
154 * Set the appropriate busy bit for the device/host.
156 * If the host/device isn't busy, assume that something actually
157 * completed, and that we should be able to queue a command now.
159 * Note that the prior mid-layer assumption that any host could
160 * always queue at least one command is now broken. The mid-layer
161 * will implement a user specifiable stall (see
162 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
163 * if a command is requeued with no other commands outstanding
164 * either for the device or for the host.
166 if (reason
== SCSI_MLQUEUE_HOST_BUSY
)
167 host
->host_blocked
= host
->max_host_blocked
;
168 else if (reason
== SCSI_MLQUEUE_DEVICE_BUSY
)
169 device
->device_blocked
= device
->max_device_blocked
;
172 * Decrement the counters, since these commands are no longer
173 * active on the host/device.
175 scsi_device_unbusy(device
);
178 * Requeue this command. It will go before all other commands
179 * that are already in the queue.
181 * NOTE: there is magic here about the way the queue is plugged if
182 * we have no outstanding commands.
184 * Although we *don't* plug the queue, we call the request
185 * function. The SCSI request function detects the blocked condition
186 * and plugs the queue appropriately.
188 spin_lock_irqsave(q
->queue_lock
, flags
);
189 blk_requeue_request(q
, cmd
->request
);
190 spin_unlock_irqrestore(q
->queue_lock
, flags
);
198 * Function: scsi_do_req
200 * Purpose: Queue a SCSI request
202 * Arguments: sreq - command descriptor.
203 * cmnd - actual SCSI command to be performed.
204 * buffer - data buffer.
205 * bufflen - size of data buffer.
206 * done - completion function to be run.
207 * timeout - how long to let it run before timeout.
208 * retries - number of retries we allow.
210 * Lock status: No locks held upon entry.
214 * Notes: This function is only used for queueing requests for things
215 * like ioctls and character device requests - this is because
216 * we essentially just inject a request into the queue for the
219 * In order to support the scsi_device_quiesce function, we
220 * now inject requests on the *head* of the device queue
221 * rather than the tail.
223 void scsi_do_req(struct scsi_request
*sreq
, const void *cmnd
,
224 void *buffer
, unsigned bufflen
,
225 void (*done
)(struct scsi_cmnd
*),
226 int timeout
, int retries
)
229 * If the upper level driver is reusing these things, then
230 * we should release the low-level block now. Another one will
231 * be allocated later when this request is getting queued.
233 __scsi_release_request(sreq
);
236 * Our own function scsi_done (which marks the host as not busy,
237 * disables the timeout counter, etc) will be called by us or by the
238 * scsi_hosts[host].queuecommand() function needs to also call
239 * the completion function for the high level driver.
241 memcpy(sreq
->sr_cmnd
, cmnd
, sizeof(sreq
->sr_cmnd
));
242 sreq
->sr_bufflen
= bufflen
;
243 sreq
->sr_buffer
= buffer
;
244 sreq
->sr_allowed
= retries
;
245 sreq
->sr_done
= done
;
246 sreq
->sr_timeout_per_command
= timeout
;
248 if (sreq
->sr_cmd_len
== 0)
249 sreq
->sr_cmd_len
= COMMAND_SIZE(sreq
->sr_cmnd
[0]);
252 * head injection *required* here otherwise quiesce won't work
254 scsi_insert_special_req(sreq
, 1);
256 EXPORT_SYMBOL(scsi_do_req
);
258 /* This is the end routine we get to if a command was never attached
259 * to the request. Simply complete the request without changing
260 * rq_status; this will cause a DRIVER_ERROR. */
261 static void scsi_wait_req_end_io(struct request
*req
)
263 BUG_ON(!req
->waiting
);
265 complete(req
->waiting
);
268 void scsi_wait_req(struct scsi_request
*sreq
, const void *cmnd
, void *buffer
,
269 unsigned bufflen
, int timeout
, int retries
)
271 DECLARE_COMPLETION(wait
);
272 int write
= (sreq
->sr_data_direction
== DMA_TO_DEVICE
);
275 req
= blk_get_request(sreq
->sr_device
->request_queue
, write
,
277 if (bufflen
&& blk_rq_map_kern(sreq
->sr_device
->request_queue
, req
,
278 buffer
, bufflen
, __GFP_WAIT
)) {
279 sreq
->sr_result
= DRIVER_ERROR
<< 24;
280 blk_put_request(req
);
284 req
->flags
|= REQ_NOMERGE
;
285 req
->waiting
= &wait
;
286 req
->end_io
= scsi_wait_req_end_io
;
287 req
->cmd_len
= COMMAND_SIZE(((u8
*)cmnd
)[0]);
288 req
->sense
= sreq
->sr_sense_buffer
;
290 memcpy(req
->cmd
, cmnd
, req
->cmd_len
);
291 req
->timeout
= timeout
;
292 req
->flags
|= REQ_BLOCK_PC
;
294 blk_insert_request(sreq
->sr_device
->request_queue
, req
,
295 sreq
->sr_data_direction
== DMA_TO_DEVICE
, NULL
);
296 wait_for_completion(&wait
);
297 sreq
->sr_request
->waiting
= NULL
;
298 sreq
->sr_result
= req
->errors
;
300 sreq
->sr_result
|= (DRIVER_ERROR
<< 24);
302 blk_put_request(req
);
305 EXPORT_SYMBOL(scsi_wait_req
);
308 * scsi_execute - insert request and wait for the result
311 * @data_direction: data direction
312 * @buffer: data buffer
313 * @bufflen: len of buffer
314 * @sense: optional sense buffer
315 * @timeout: request timeout in seconds
316 * @retries: number of times to retry request
317 * @flags: or into request flags;
319 * returns the req->errors value which is the the scsi_cmnd result
322 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
323 int data_direction
, void *buffer
, unsigned bufflen
,
324 unsigned char *sense
, int timeout
, int retries
, int flags
)
327 int write
= (data_direction
== DMA_TO_DEVICE
);
328 int ret
= DRIVER_ERROR
<< 24;
330 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
332 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
333 buffer
, bufflen
, __GFP_WAIT
))
336 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
337 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
340 req
->timeout
= timeout
;
341 req
->flags
|= flags
| REQ_BLOCK_PC
| REQ_SPECIAL
| REQ_QUIET
;
344 * head injection *required* here otherwise quiesce won't work
346 blk_execute_rq(req
->q
, NULL
, req
, 1);
350 blk_put_request(req
);
354 EXPORT_SYMBOL(scsi_execute
);
357 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
358 int data_direction
, void *buffer
, unsigned bufflen
,
359 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
365 sense
= kmalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
367 return DRIVER_ERROR
<< 24;
368 memset(sense
, 0, SCSI_SENSE_BUFFERSIZE
);
370 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
371 sense
, timeout
, retries
, 0);
373 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
378 EXPORT_SYMBOL(scsi_execute_req
);
381 * Function: scsi_init_cmd_errh()
383 * Purpose: Initialize cmd fields related to error handling.
385 * Arguments: cmd - command that is ready to be queued.
389 * Notes: This function has the job of initializing a number of
390 * fields related to error handling. Typically this will
391 * be called once for each command, as required.
393 static int scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
395 cmd
->serial_number
= 0;
397 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
399 if (cmd
->cmd_len
== 0)
400 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
403 * We need saved copies of a number of fields - this is because
404 * error handling may need to overwrite these with different values
405 * to run different commands, and once error handling is complete,
406 * we will need to restore these values prior to running the actual
409 cmd
->old_use_sg
= cmd
->use_sg
;
410 cmd
->old_cmd_len
= cmd
->cmd_len
;
411 cmd
->sc_old_data_direction
= cmd
->sc_data_direction
;
412 cmd
->old_underflow
= cmd
->underflow
;
413 memcpy(cmd
->data_cmnd
, cmd
->cmnd
, sizeof(cmd
->cmnd
));
414 cmd
->buffer
= cmd
->request_buffer
;
415 cmd
->bufflen
= cmd
->request_bufflen
;
421 * Function: scsi_setup_cmd_retry()
423 * Purpose: Restore the command state for a retry
425 * Arguments: cmd - command to be restored
429 * Notes: Immediately prior to retrying a command, we need
430 * to restore certain fields that we saved above.
432 void scsi_setup_cmd_retry(struct scsi_cmnd
*cmd
)
434 memcpy(cmd
->cmnd
, cmd
->data_cmnd
, sizeof(cmd
->data_cmnd
));
435 cmd
->request_buffer
= cmd
->buffer
;
436 cmd
->request_bufflen
= cmd
->bufflen
;
437 cmd
->use_sg
= cmd
->old_use_sg
;
438 cmd
->cmd_len
= cmd
->old_cmd_len
;
439 cmd
->sc_data_direction
= cmd
->sc_old_data_direction
;
440 cmd
->underflow
= cmd
->old_underflow
;
443 void scsi_device_unbusy(struct scsi_device
*sdev
)
445 struct Scsi_Host
*shost
= sdev
->host
;
448 spin_lock_irqsave(shost
->host_lock
, flags
);
450 if (unlikely(scsi_host_in_recovery(shost
) &&
452 scsi_eh_wakeup(shost
);
453 spin_unlock(shost
->host_lock
);
454 spin_lock(sdev
->request_queue
->queue_lock
);
456 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
460 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
461 * and call blk_run_queue for all the scsi_devices on the target -
462 * including current_sdev first.
464 * Called with *no* scsi locks held.
466 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
468 struct Scsi_Host
*shost
= current_sdev
->host
;
469 struct scsi_device
*sdev
, *tmp
;
470 struct scsi_target
*starget
= scsi_target(current_sdev
);
473 spin_lock_irqsave(shost
->host_lock
, flags
);
474 starget
->starget_sdev_user
= NULL
;
475 spin_unlock_irqrestore(shost
->host_lock
, flags
);
478 * Call blk_run_queue for all LUNs on the target, starting with
479 * current_sdev. We race with others (to set starget_sdev_user),
480 * but in most cases, we will be first. Ideally, each LU on the
481 * target would get some limited time or requests on the target.
483 blk_run_queue(current_sdev
->request_queue
);
485 spin_lock_irqsave(shost
->host_lock
, flags
);
486 if (starget
->starget_sdev_user
)
488 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
489 same_target_siblings
) {
490 if (sdev
== current_sdev
)
492 if (scsi_device_get(sdev
))
495 spin_unlock_irqrestore(shost
->host_lock
, flags
);
496 blk_run_queue(sdev
->request_queue
);
497 spin_lock_irqsave(shost
->host_lock
, flags
);
499 scsi_device_put(sdev
);
502 spin_unlock_irqrestore(shost
->host_lock
, flags
);
506 * Function: scsi_run_queue()
508 * Purpose: Select a proper request queue to serve next
510 * Arguments: q - last request's queue
514 * Notes: The previous command was completely finished, start
515 * a new one if possible.
517 static void scsi_run_queue(struct request_queue
*q
)
519 struct scsi_device
*sdev
= q
->queuedata
;
520 struct Scsi_Host
*shost
= sdev
->host
;
523 if (sdev
->single_lun
)
524 scsi_single_lun_run(sdev
);
526 spin_lock_irqsave(shost
->host_lock
, flags
);
527 while (!list_empty(&shost
->starved_list
) &&
528 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
529 !((shost
->can_queue
> 0) &&
530 (shost
->host_busy
>= shost
->can_queue
))) {
532 * As long as shost is accepting commands and we have
533 * starved queues, call blk_run_queue. scsi_request_fn
534 * drops the queue_lock and can add us back to the
537 * host_lock protects the starved_list and starved_entry.
538 * scsi_request_fn must get the host_lock before checking
539 * or modifying starved_list or starved_entry.
541 sdev
= list_entry(shost
->starved_list
.next
,
542 struct scsi_device
, starved_entry
);
543 list_del_init(&sdev
->starved_entry
);
544 spin_unlock_irqrestore(shost
->host_lock
, flags
);
546 blk_run_queue(sdev
->request_queue
);
548 spin_lock_irqsave(shost
->host_lock
, flags
);
549 if (unlikely(!list_empty(&sdev
->starved_entry
)))
551 * sdev lost a race, and was put back on the
552 * starved list. This is unlikely but without this
553 * in theory we could loop forever.
557 spin_unlock_irqrestore(shost
->host_lock
, flags
);
563 * Function: scsi_requeue_command()
565 * Purpose: Handle post-processing of completed commands.
567 * Arguments: q - queue to operate on
568 * cmd - command that may need to be requeued.
572 * Notes: After command completion, there may be blocks left
573 * over which weren't finished by the previous command
574 * this can be for a number of reasons - the main one is
575 * I/O errors in the middle of the request, in which case
576 * we need to request the blocks that come after the bad
578 * Notes: Upon return, cmd is a stale pointer.
580 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
582 struct request
*req
= cmd
->request
;
585 scsi_unprep_request(req
);
586 spin_lock_irqsave(q
->queue_lock
, flags
);
587 blk_requeue_request(q
, req
);
588 spin_unlock_irqrestore(q
->queue_lock
, flags
);
593 void scsi_next_command(struct scsi_cmnd
*cmd
)
595 struct request_queue
*q
= cmd
->device
->request_queue
;
597 scsi_put_command(cmd
);
601 void scsi_run_host_queues(struct Scsi_Host
*shost
)
603 struct scsi_device
*sdev
;
605 shost_for_each_device(sdev
, shost
)
606 scsi_run_queue(sdev
->request_queue
);
610 * Function: scsi_end_request()
612 * Purpose: Post-processing of completed commands (usually invoked at end
613 * of upper level post-processing and scsi_io_completion).
615 * Arguments: cmd - command that is complete.
616 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
617 * bytes - number of bytes of completed I/O
618 * requeue - indicates whether we should requeue leftovers.
620 * Lock status: Assumed that lock is not held upon entry.
622 * Returns: cmd if requeue required, NULL otherwise.
624 * Notes: This is called for block device requests in order to
625 * mark some number of sectors as complete.
627 * We are guaranteeing that the request queue will be goosed
628 * at some point during this call.
629 * Notes: If cmd was requeued, upon return it will be a stale pointer.
631 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
632 int bytes
, int requeue
)
634 request_queue_t
*q
= cmd
->device
->request_queue
;
635 struct request
*req
= cmd
->request
;
639 * If there are blocks left over at the end, set up the command
640 * to queue the remainder of them.
642 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
643 int leftover
= (req
->hard_nr_sectors
<< 9);
645 if (blk_pc_request(req
))
646 leftover
= req
->data_len
;
648 /* kill remainder if no retrys */
649 if (!uptodate
&& blk_noretry_request(req
))
650 end_that_request_chunk(req
, 0, leftover
);
654 * Bleah. Leftovers again. Stick the
655 * leftovers in the front of the
656 * queue, and goose the queue again.
658 scsi_requeue_command(q
, cmd
);
665 add_disk_randomness(req
->rq_disk
);
667 spin_lock_irqsave(q
->queue_lock
, flags
);
668 if (blk_rq_tagged(req
))
669 blk_queue_end_tag(q
, req
);
670 end_that_request_last(req
);
671 spin_unlock_irqrestore(q
->queue_lock
, flags
);
674 * This will goose the queue request function at the end, so we don't
675 * need to worry about launching another command.
677 scsi_next_command(cmd
);
681 static struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, int gfp_mask
)
683 struct scsi_host_sg_pool
*sgp
;
684 struct scatterlist
*sgl
;
686 BUG_ON(!cmd
->use_sg
);
688 switch (cmd
->use_sg
) {
698 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
702 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
706 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
717 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
718 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
722 static void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
724 struct scsi_host_sg_pool
*sgp
;
726 BUG_ON(index
>= SG_MEMPOOL_NR
);
728 sgp
= scsi_sg_pools
+ index
;
729 mempool_free(sgl
, sgp
->pool
);
733 * Function: scsi_release_buffers()
735 * Purpose: Completion processing for block device I/O requests.
737 * Arguments: cmd - command that we are bailing.
739 * Lock status: Assumed that no lock is held upon entry.
743 * Notes: In the event that an upper level driver rejects a
744 * command, we must release resources allocated during
745 * the __init_io() function. Primarily this would involve
746 * the scatter-gather table, and potentially any bounce
749 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
751 struct request
*req
= cmd
->request
;
754 * Free up any indirection buffers we allocated for DMA purposes.
757 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
758 else if (cmd
->request_buffer
!= req
->buffer
)
759 kfree(cmd
->request_buffer
);
762 * Zero these out. They now point to freed memory, and it is
763 * dangerous to hang onto the pointers.
767 cmd
->request_buffer
= NULL
;
768 cmd
->request_bufflen
= 0;
772 * Function: scsi_io_completion()
774 * Purpose: Completion processing for block device I/O requests.
776 * Arguments: cmd - command that is finished.
778 * Lock status: Assumed that no lock is held upon entry.
782 * Notes: This function is matched in terms of capabilities to
783 * the function that created the scatter-gather list.
784 * In other words, if there are no bounce buffers
785 * (the normal case for most drivers), we don't need
786 * the logic to deal with cleaning up afterwards.
788 * We must do one of several things here:
790 * a) Call scsi_end_request. This will finish off the
791 * specified number of sectors. If we are done, the
792 * command block will be released, and the queue
793 * function will be goosed. If we are not done, then
794 * scsi_end_request will directly goose the queue.
796 * b) We can just use scsi_requeue_command() here. This would
797 * be used if we just wanted to retry, for example.
799 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
,
800 unsigned int block_bytes
)
802 int result
= cmd
->result
;
803 int this_count
= cmd
->bufflen
;
804 request_queue_t
*q
= cmd
->device
->request_queue
;
805 struct request
*req
= cmd
->request
;
806 int clear_errors
= 1;
807 struct scsi_sense_hdr sshdr
;
809 int sense_deferred
= 0;
811 if (blk_complete_barrier_rq(q
, req
, good_bytes
>> 9))
815 * Free up any indirection buffers we allocated for DMA purposes.
816 * For the case of a READ, we need to copy the data out of the
817 * bounce buffer and into the real buffer.
820 scsi_free_sgtable(cmd
->buffer
, cmd
->sglist_len
);
821 else if (cmd
->buffer
!= req
->buffer
) {
822 if (rq_data_dir(req
) == READ
) {
824 char *to
= bio_kmap_irq(req
->bio
, &flags
);
825 memcpy(to
, cmd
->buffer
, cmd
->bufflen
);
826 bio_kunmap_irq(to
, &flags
);
832 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
834 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
836 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
837 req
->errors
= result
;
840 if (sense_valid
&& req
->sense
) {
842 * SG_IO wants current and deferred errors
844 int len
= 8 + cmd
->sense_buffer
[7];
846 if (len
> SCSI_SENSE_BUFFERSIZE
)
847 len
= SCSI_SENSE_BUFFERSIZE
;
848 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
849 req
->sense_len
= len
;
852 req
->data_len
= cmd
->resid
;
856 * Zero these out. They now point to freed memory, and it is
857 * dangerous to hang onto the pointers.
861 cmd
->request_buffer
= NULL
;
862 cmd
->request_bufflen
= 0;
865 * Next deal with any sectors which we were able to correctly
868 if (good_bytes
>= 0) {
869 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n",
870 req
->nr_sectors
, good_bytes
));
871 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
876 * If multiple sectors are requested in one buffer, then
877 * they will have been finished off by the first command.
878 * If not, then we have a multi-buffer command.
880 * If block_bytes != 0, it means we had a medium error
881 * of some sort, and that we want to mark some number of
882 * sectors as not uptodate. Thus we want to inhibit
883 * requeueing right here - we will requeue down below
884 * when we handle the bad sectors.
888 * If the command completed without error, then either
889 * finish off the rest of the command, or start a new one.
891 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
895 * Now, if we were good little boys and girls, Santa left us a request
896 * sense buffer. We can extract information from this, so we
897 * can choose a block to remap, etc.
899 if (sense_valid
&& !sense_deferred
) {
900 switch (sshdr
.sense_key
) {
902 if (cmd
->device
->removable
) {
903 /* detected disc change. set a bit
904 * and quietly refuse further access.
906 cmd
->device
->changed
= 1;
907 scsi_end_request(cmd
, 0,
912 * Must have been a power glitch, or a
913 * bus reset. Could not have been a
914 * media change, so we just retry the
915 * request and see what happens.
917 scsi_requeue_command(q
, cmd
);
921 case ILLEGAL_REQUEST
:
923 * If we had an ILLEGAL REQUEST returned, then we may
924 * have performed an unsupported command. The only
925 * thing this should be would be a ten byte read where
926 * only a six byte read was supported. Also, on a
927 * system where READ CAPACITY failed, we may have read
928 * past the end of the disk.
930 if (cmd
->device
->use_10_for_rw
&&
931 (cmd
->cmnd
[0] == READ_10
||
932 cmd
->cmnd
[0] == WRITE_10
)) {
933 cmd
->device
->use_10_for_rw
= 0;
935 * This will cause a retry with a 6-byte
938 scsi_requeue_command(q
, cmd
);
941 scsi_end_request(cmd
, 0, this_count
, 1);
947 * If the device is in the process of becoming ready,
950 if (sshdr
.asc
== 0x04 && sshdr
.ascq
== 0x01) {
951 scsi_requeue_command(q
, cmd
);
954 if (!(req
->flags
& REQ_QUIET
))
955 dev_printk(KERN_INFO
,
956 &cmd
->device
->sdev_gendev
,
957 "Device not ready.\n");
958 scsi_end_request(cmd
, 0, this_count
, 1);
960 case VOLUME_OVERFLOW
:
961 if (!(req
->flags
& REQ_QUIET
)) {
962 dev_printk(KERN_INFO
,
963 &cmd
->device
->sdev_gendev
,
964 "Volume overflow, CDB: ");
965 __scsi_print_command(cmd
->data_cmnd
);
966 scsi_print_sense("", cmd
);
968 scsi_end_request(cmd
, 0, block_bytes
, 1);
973 } /* driver byte != 0 */
974 if (host_byte(result
) == DID_RESET
) {
976 * Third party bus reset or reset for error
977 * recovery reasons. Just retry the request
978 * and see what happens.
980 scsi_requeue_command(q
, cmd
);
984 if (!(req
->flags
& REQ_QUIET
)) {
985 dev_printk(KERN_INFO
, &cmd
->device
->sdev_gendev
,
986 "SCSI error: return code = 0x%x\n", result
);
988 if (driver_byte(result
) & DRIVER_SENSE
)
989 scsi_print_sense("", cmd
);
992 * Mark a single buffer as not uptodate. Queue the remainder.
993 * We sometimes get this cruft in the event that a medium error
994 * isn't properly reported.
996 block_bytes
= req
->hard_cur_sectors
<< 9;
998 block_bytes
= req
->data_len
;
999 scsi_end_request(cmd
, 0, block_bytes
, 1);
1002 EXPORT_SYMBOL(scsi_io_completion
);
1005 * Function: scsi_init_io()
1007 * Purpose: SCSI I/O initialize function.
1009 * Arguments: cmd - Command descriptor we wish to initialize
1011 * Returns: 0 on success
1012 * BLKPREP_DEFER if the failure is retryable
1013 * BLKPREP_KILL if the failure is fatal
1015 static int scsi_init_io(struct scsi_cmnd
*cmd
)
1017 struct request
*req
= cmd
->request
;
1018 struct scatterlist
*sgpnt
;
1022 * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
1024 if ((req
->flags
& REQ_BLOCK_PC
) && !req
->bio
) {
1025 cmd
->request_bufflen
= req
->data_len
;
1026 cmd
->request_buffer
= req
->data
;
1027 req
->buffer
= req
->data
;
1033 * we used to not use scatter-gather for single segment request,
1034 * but now we do (it makes highmem I/O easier to support without
1037 cmd
->use_sg
= req
->nr_phys_segments
;
1040 * if sg table allocation fails, requeue request later.
1042 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
1043 if (unlikely(!sgpnt
))
1044 return BLKPREP_DEFER
;
1046 cmd
->request_buffer
= (char *) sgpnt
;
1047 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1048 if (blk_pc_request(req
))
1049 cmd
->request_bufflen
= req
->data_len
;
1053 * Next, walk the list, and fill in the addresses and sizes of
1056 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1059 * mapped well, send it off
1061 if (likely(count
<= cmd
->use_sg
)) {
1062 cmd
->use_sg
= count
;
1066 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1067 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1068 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1069 req
->current_nr_sectors
);
1071 /* release the command and kill it */
1072 scsi_release_buffers(cmd
);
1073 scsi_put_command(cmd
);
1074 return BLKPREP_KILL
;
1077 static int scsi_prepare_flush_fn(request_queue_t
*q
, struct request
*rq
)
1079 struct scsi_device
*sdev
= q
->queuedata
;
1080 struct scsi_driver
*drv
;
1082 if (sdev
->sdev_state
== SDEV_RUNNING
) {
1083 drv
= *(struct scsi_driver
**) rq
->rq_disk
->private_data
;
1085 if (drv
->prepare_flush
)
1086 return drv
->prepare_flush(q
, rq
);
1092 static void scsi_end_flush_fn(request_queue_t
*q
, struct request
*rq
)
1094 struct scsi_device
*sdev
= q
->queuedata
;
1095 struct request
*flush_rq
= rq
->end_io_data
;
1096 struct scsi_driver
*drv
;
1098 if (flush_rq
->errors
) {
1099 printk("scsi: barrier error, disabling flush support\n");
1100 blk_queue_ordered(q
, QUEUE_ORDERED_NONE
);
1103 if (sdev
->sdev_state
== SDEV_RUNNING
) {
1104 drv
= *(struct scsi_driver
**) rq
->rq_disk
->private_data
;
1105 drv
->end_flush(q
, rq
);
1109 static int scsi_issue_flush_fn(request_queue_t
*q
, struct gendisk
*disk
,
1110 sector_t
*error_sector
)
1112 struct scsi_device
*sdev
= q
->queuedata
;
1113 struct scsi_driver
*drv
;
1115 if (sdev
->sdev_state
!= SDEV_RUNNING
)
1118 drv
= *(struct scsi_driver
**) disk
->private_data
;
1119 if (drv
->issue_flush
)
1120 return drv
->issue_flush(&sdev
->sdev_gendev
, error_sector
);
1125 static void scsi_generic_done(struct scsi_cmnd
*cmd
)
1127 BUG_ON(!blk_pc_request(cmd
->request
));
1128 scsi_io_completion(cmd
, cmd
->result
== 0 ? cmd
->bufflen
: 0, 0);
1131 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1133 struct scsi_device
*sdev
= q
->queuedata
;
1134 struct scsi_cmnd
*cmd
;
1135 int specials_only
= 0;
1138 * Just check to see if the device is online. If it isn't, we
1139 * refuse to process any commands. The device must be brought
1140 * online before trying any recovery commands
1142 if (unlikely(!scsi_device_online(sdev
))) {
1143 printk(KERN_ERR
"scsi%d (%d:%d): rejecting I/O to offline device\n",
1144 sdev
->host
->host_no
, sdev
->id
, sdev
->lun
);
1147 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1148 /* OK, we're not in a running state don't prep
1150 if (sdev
->sdev_state
== SDEV_DEL
) {
1151 /* Device is fully deleted, no commands
1152 * at all allowed down */
1153 printk(KERN_ERR
"scsi%d (%d:%d): rejecting I/O to dead device\n",
1154 sdev
->host
->host_no
, sdev
->id
, sdev
->lun
);
1157 /* OK, we only allow special commands (i.e. not
1158 * user initiated ones */
1159 specials_only
= sdev
->sdev_state
;
1163 * Find the actual device driver associated with this command.
1164 * The SPECIAL requests are things like character device or
1165 * ioctls, which did not originate from ll_rw_blk. Note that
1166 * the special field is also used to indicate the cmd for
1167 * the remainder of a partially fulfilled request that can
1168 * come up when there is a medium error. We have to treat
1169 * these two cases differently. We differentiate by looking
1170 * at request->cmd, as this tells us the real story.
1172 if (req
->flags
& REQ_SPECIAL
&& req
->special
) {
1173 struct scsi_request
*sreq
= req
->special
;
1175 if (sreq
->sr_magic
== SCSI_REQ_MAGIC
) {
1176 cmd
= scsi_get_command(sreq
->sr_device
, GFP_ATOMIC
);
1179 scsi_init_cmd_from_req(cmd
, sreq
);
1182 } else if (req
->flags
& (REQ_CMD
| REQ_BLOCK_PC
)) {
1184 if(unlikely(specials_only
) && !(req
->flags
& REQ_SPECIAL
)) {
1185 if(specials_only
== SDEV_QUIESCE
||
1186 specials_only
== SDEV_BLOCK
)
1189 printk(KERN_ERR
"scsi%d (%d:%d): rejecting I/O to device being removed\n",
1190 sdev
->host
->host_no
, sdev
->id
, sdev
->lun
);
1196 * Now try and find a command block that we can use.
1198 if (!req
->special
) {
1199 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1205 /* pull a tag out of the request if we have one */
1206 cmd
->tag
= req
->tag
;
1208 blk_dump_rq_flags(req
, "SCSI bad req");
1212 /* note the overloading of req->special. When the tag
1213 * is active it always means cmd. If the tag goes
1214 * back for re-queueing, it may be reset */
1219 * FIXME: drop the lock here because the functions below
1220 * expect to be called without the queue lock held. Also,
1221 * previously, we dequeued the request before dropping the
1222 * lock. We hope REQ_STARTED prevents anything untoward from
1225 if (req
->flags
& (REQ_CMD
| REQ_BLOCK_PC
)) {
1226 struct scsi_driver
*drv
;
1230 * This will do a couple of things:
1231 * 1) Fill in the actual SCSI command.
1232 * 2) Fill in any other upper-level specific fields
1235 * If this returns 0, it means that the request failed
1236 * (reading past end of disk, reading offline device,
1237 * etc). This won't actually talk to the device, but
1238 * some kinds of consistency checking may cause the
1239 * request to be rejected immediately.
1243 * This sets up the scatter-gather table (allocating if
1246 ret
= scsi_init_io(cmd
);
1249 /* BLKPREP_KILL return also releases the command */
1256 * Initialize the actual SCSI command for this request.
1259 drv
= *(struct scsi_driver
**)req
->rq_disk
->private_data
;
1260 if (unlikely(!drv
->init_command(cmd
))) {
1261 scsi_release_buffers(cmd
);
1262 scsi_put_command(cmd
);
1266 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1267 cmd
->cmd_len
= req
->cmd_len
;
1268 if (rq_data_dir(req
) == WRITE
)
1269 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1270 else if (req
->data_len
)
1271 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1273 cmd
->sc_data_direction
= DMA_NONE
;
1275 cmd
->transfersize
= req
->data_len
;
1277 cmd
->timeout_per_command
= req
->timeout
;
1278 cmd
->done
= scsi_generic_done
;
1283 * The request is now prepped, no need to come back here
1285 req
->flags
|= REQ_DONTPREP
;
1289 /* If we defer, the elv_next_request() returns NULL, but the
1290 * queue must be restarted, so we plug here if no returning
1291 * command will automatically do that. */
1292 if (sdev
->device_busy
== 0)
1294 return BLKPREP_DEFER
;
1296 req
->errors
= DID_NO_CONNECT
<< 16;
1297 return BLKPREP_KILL
;
1301 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1304 * Called with the queue_lock held.
1306 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1307 struct scsi_device
*sdev
)
1309 if (sdev
->device_busy
>= sdev
->queue_depth
)
1311 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1313 * unblock after device_blocked iterates to zero
1315 if (--sdev
->device_blocked
== 0) {
1317 printk("scsi%d (%d:%d) unblocking device at"
1318 " zero depth\n", sdev
->host
->host_no
,
1319 sdev
->id
, sdev
->lun
));
1325 if (sdev
->device_blocked
)
1332 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1333 * return 0. We must end up running the queue again whenever 0 is
1334 * returned, else IO can hang.
1336 * Called with host_lock held.
1338 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1339 struct Scsi_Host
*shost
,
1340 struct scsi_device
*sdev
)
1342 if (scsi_host_in_recovery(shost
))
1344 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1346 * unblock after host_blocked iterates to zero
1348 if (--shost
->host_blocked
== 0) {
1350 printk("scsi%d unblocking host at zero depth\n",
1357 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1358 shost
->host_blocked
|| shost
->host_self_blocked
) {
1359 if (list_empty(&sdev
->starved_entry
))
1360 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1364 /* We're OK to process the command, so we can't be starved */
1365 if (!list_empty(&sdev
->starved_entry
))
1366 list_del_init(&sdev
->starved_entry
);
1372 * Kill a request for a dead device
1374 static void scsi_kill_request(struct request
*req
, request_queue_t
*q
)
1376 struct scsi_cmnd
*cmd
= req
->special
;
1378 blkdev_dequeue_request(req
);
1380 if (unlikely(cmd
== NULL
)) {
1381 printk(KERN_CRIT
"impossible request in %s.\n",
1386 scsi_init_cmd_errh(cmd
);
1387 cmd
->result
= DID_NO_CONNECT
<< 16;
1388 atomic_inc(&cmd
->device
->iorequest_cnt
);
1393 * Function: scsi_request_fn()
1395 * Purpose: Main strategy routine for SCSI.
1397 * Arguments: q - Pointer to actual queue.
1401 * Lock status: IO request lock assumed to be held when called.
1403 static void scsi_request_fn(struct request_queue
*q
)
1405 struct scsi_device
*sdev
= q
->queuedata
;
1406 struct Scsi_Host
*shost
;
1407 struct scsi_cmnd
*cmd
;
1408 struct request
*req
;
1411 printk("scsi: killing requests for dead queue\n");
1412 while ((req
= elv_next_request(q
)) != NULL
)
1413 scsi_kill_request(req
, q
);
1417 if(!get_device(&sdev
->sdev_gendev
))
1418 /* We must be tearing the block queue down already */
1422 * To start with, we keep looping until the queue is empty, or until
1423 * the host is no longer able to accept any more requests.
1426 while (!blk_queue_plugged(q
)) {
1429 * get next queueable request. We do this early to make sure
1430 * that the request is fully prepared even if we cannot
1433 req
= elv_next_request(q
);
1434 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1437 if (unlikely(!scsi_device_online(sdev
))) {
1438 printk(KERN_ERR
"scsi%d (%d:%d): rejecting I/O to offline device\n",
1439 sdev
->host
->host_no
, sdev
->id
, sdev
->lun
);
1440 scsi_kill_request(req
, q
);
1446 * Remove the request from the request list.
1448 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1449 blkdev_dequeue_request(req
);
1450 sdev
->device_busy
++;
1452 spin_unlock(q
->queue_lock
);
1454 if (unlikely(cmd
== NULL
)) {
1455 printk(KERN_CRIT
"impossible request in %s.\n"
1456 "please mail a stack trace to "
1457 "linux-scsi@vger.kernel.org",
1461 spin_lock(shost
->host_lock
);
1463 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1465 if (sdev
->single_lun
) {
1466 if (scsi_target(sdev
)->starget_sdev_user
&&
1467 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1469 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1474 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1475 * take the lock again.
1477 spin_unlock_irq(shost
->host_lock
);
1480 * Finally, initialize any error handling parameters, and set up
1481 * the timers for timeouts.
1483 scsi_init_cmd_errh(cmd
);
1486 * Dispatch the command to the low-level driver.
1488 rtn
= scsi_dispatch_cmd(cmd
);
1489 spin_lock_irq(q
->queue_lock
);
1491 /* we're refusing the command; because of
1492 * the way locks get dropped, we need to
1493 * check here if plugging is required */
1494 if(sdev
->device_busy
== 0)
1504 spin_unlock_irq(shost
->host_lock
);
1507 * lock q, handle tag, requeue req, and decrement device_busy. We
1508 * must return with queue_lock held.
1510 * Decrementing device_busy without checking it is OK, as all such
1511 * cases (host limits or settings) should run the queue at some
1514 spin_lock_irq(q
->queue_lock
);
1515 blk_requeue_request(q
, req
);
1516 sdev
->device_busy
--;
1517 if(sdev
->device_busy
== 0)
1520 /* must be careful here...if we trigger the ->remove() function
1521 * we cannot be holding the q lock */
1522 spin_unlock_irq(q
->queue_lock
);
1523 put_device(&sdev
->sdev_gendev
);
1524 spin_lock_irq(q
->queue_lock
);
1527 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1529 struct device
*host_dev
;
1530 u64 bounce_limit
= 0xffffffff;
1532 if (shost
->unchecked_isa_dma
)
1533 return BLK_BOUNCE_ISA
;
1535 * Platforms with virtual-DMA translation
1536 * hardware have no practical limit.
1538 if (!PCI_DMA_BUS_IS_PHYS
)
1539 return BLK_BOUNCE_ANY
;
1541 host_dev
= scsi_get_device(shost
);
1542 if (host_dev
&& host_dev
->dma_mask
)
1543 bounce_limit
= *host_dev
->dma_mask
;
1545 return bounce_limit
;
1547 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1549 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1551 struct Scsi_Host
*shost
= sdev
->host
;
1552 struct request_queue
*q
;
1554 q
= blk_init_queue(scsi_request_fn
, NULL
);
1558 blk_queue_prep_rq(q
, scsi_prep_fn
);
1560 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1561 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1562 blk_queue_max_sectors(q
, shost
->max_sectors
);
1563 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1564 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1565 blk_queue_issue_flush_fn(q
, scsi_issue_flush_fn
);
1568 * ordered tags are superior to flush ordering
1570 if (shost
->ordered_tag
)
1571 blk_queue_ordered(q
, QUEUE_ORDERED_TAG
);
1572 else if (shost
->ordered_flush
) {
1573 blk_queue_ordered(q
, QUEUE_ORDERED_FLUSH
);
1574 q
->prepare_flush_fn
= scsi_prepare_flush_fn
;
1575 q
->end_flush_fn
= scsi_end_flush_fn
;
1578 if (!shost
->use_clustering
)
1579 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1583 void scsi_free_queue(struct request_queue
*q
)
1585 blk_cleanup_queue(q
);
1589 * Function: scsi_block_requests()
1591 * Purpose: Utility function used by low-level drivers to prevent further
1592 * commands from being queued to the device.
1594 * Arguments: shost - Host in question
1598 * Lock status: No locks are assumed held.
1600 * Notes: There is no timer nor any other means by which the requests
1601 * get unblocked other than the low-level driver calling
1602 * scsi_unblock_requests().
1604 void scsi_block_requests(struct Scsi_Host
*shost
)
1606 shost
->host_self_blocked
= 1;
1608 EXPORT_SYMBOL(scsi_block_requests
);
1611 * Function: scsi_unblock_requests()
1613 * Purpose: Utility function used by low-level drivers to allow further
1614 * commands from being queued to the device.
1616 * Arguments: shost - Host in question
1620 * Lock status: No locks are assumed held.
1622 * Notes: There is no timer nor any other means by which the requests
1623 * get unblocked other than the low-level driver calling
1624 * scsi_unblock_requests().
1626 * This is done as an API function so that changes to the
1627 * internals of the scsi mid-layer won't require wholesale
1628 * changes to drivers that use this feature.
1630 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1632 shost
->host_self_blocked
= 0;
1633 scsi_run_host_queues(shost
);
1635 EXPORT_SYMBOL(scsi_unblock_requests
);
1637 int __init
scsi_init_queue(void)
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(SG_MEMPOOL_SIZE
,
1653 mempool_alloc_slab
, mempool_free_slab
,
1656 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1664 void scsi_exit_queue(void)
1668 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1669 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1670 mempool_destroy(sgp
->pool
);
1671 kmem_cache_destroy(sgp
->slab
);
1675 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1676 * six bytes if necessary.
1677 * @sdev: SCSI device to be queried
1678 * @dbd: set if mode sense will allow block descriptors to be returned
1679 * @modepage: mode page being requested
1680 * @buffer: request buffer (may not be smaller than eight bytes)
1681 * @len: length of request buffer.
1682 * @timeout: command timeout
1683 * @retries: number of retries before failing
1684 * @data: returns a structure abstracting the mode header data
1685 * @sense: place to put sense data (or NULL if no sense to be collected).
1686 * must be SCSI_SENSE_BUFFERSIZE big.
1688 * Returns zero if unsuccessful, or the header offset (either 4
1689 * or 8 depending on whether a six or ten byte command was
1690 * issued) if successful.
1693 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1694 unsigned char *buffer
, int len
, int timeout
, int retries
,
1695 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
) {
1696 unsigned char cmd
[12];
1700 struct scsi_sense_hdr my_sshdr
;
1702 memset(data
, 0, sizeof(*data
));
1703 memset(&cmd
[0], 0, 12);
1704 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1707 /* caller might not be interested in sense, but we need it */
1712 use_10_for_ms
= sdev
->use_10_for_ms
;
1714 if (use_10_for_ms
) {
1718 cmd
[0] = MODE_SENSE_10
;
1725 cmd
[0] = MODE_SENSE
;
1730 memset(buffer
, 0, len
);
1732 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1733 sshdr
, timeout
, retries
);
1735 /* This code looks awful: what it's doing is making sure an
1736 * ILLEGAL REQUEST sense return identifies the actual command
1737 * byte as the problem. MODE_SENSE commands can return
1738 * ILLEGAL REQUEST if the code page isn't supported */
1740 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1741 (driver_byte(result
) & DRIVER_SENSE
)) {
1742 if (scsi_sense_valid(sshdr
)) {
1743 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1744 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1746 * Invalid command operation code
1748 sdev
->use_10_for_ms
= 0;
1754 if(scsi_status_is_good(result
)) {
1755 data
->header_length
= header_length
;
1757 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1758 data
->medium_type
= buffer
[2];
1759 data
->device_specific
= buffer
[3];
1760 data
->longlba
= buffer
[4] & 0x01;
1761 data
->block_descriptor_length
= buffer
[6]*256
1764 data
->length
= buffer
[0] + 1;
1765 data
->medium_type
= buffer
[1];
1766 data
->device_specific
= buffer
[2];
1767 data
->block_descriptor_length
= buffer
[3];
1773 EXPORT_SYMBOL(scsi_mode_sense
);
1776 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1779 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1781 struct scsi_sense_hdr sshdr
;
1784 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1787 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1789 if ((scsi_sense_valid(&sshdr
)) &&
1790 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1791 (sshdr
.sense_key
== NOT_READY
))) {
1798 EXPORT_SYMBOL(scsi_test_unit_ready
);
1801 * scsi_device_set_state - Take the given device through the device
1803 * @sdev: scsi device to change the state of.
1804 * @state: state to change to.
1806 * Returns zero if unsuccessful or an error if the requested
1807 * transition is illegal.
1810 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1812 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1814 if (state
== oldstate
)
1819 /* There are no legal states that come back to
1820 * created. This is the manually initialised start
1890 sdev
->sdev_state
= state
;
1894 SCSI_LOG_ERROR_RECOVERY(1,
1895 dev_printk(KERN_ERR
, &sdev
->sdev_gendev
,
1896 "Illegal state transition %s->%s\n",
1897 scsi_device_state_name(oldstate
),
1898 scsi_device_state_name(state
))
1902 EXPORT_SYMBOL(scsi_device_set_state
);
1905 * scsi_device_quiesce - Block user issued commands.
1906 * @sdev: scsi device to quiesce.
1908 * This works by trying to transition to the SDEV_QUIESCE state
1909 * (which must be a legal transition). When the device is in this
1910 * state, only special requests will be accepted, all others will
1911 * be deferred. Since special requests may also be requeued requests,
1912 * a successful return doesn't guarantee the device will be
1913 * totally quiescent.
1915 * Must be called with user context, may sleep.
1917 * Returns zero if unsuccessful or an error if not.
1920 scsi_device_quiesce(struct scsi_device
*sdev
)
1922 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
1926 scsi_run_queue(sdev
->request_queue
);
1927 while (sdev
->device_busy
) {
1928 msleep_interruptible(200);
1929 scsi_run_queue(sdev
->request_queue
);
1933 EXPORT_SYMBOL(scsi_device_quiesce
);
1936 * scsi_device_resume - Restart user issued commands to a quiesced device.
1937 * @sdev: scsi device to resume.
1939 * Moves the device from quiesced back to running and restarts the
1942 * Must be called with user context, may sleep.
1945 scsi_device_resume(struct scsi_device
*sdev
)
1947 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
1949 scsi_run_queue(sdev
->request_queue
);
1951 EXPORT_SYMBOL(scsi_device_resume
);
1954 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
1956 scsi_device_quiesce(sdev
);
1960 scsi_target_quiesce(struct scsi_target
*starget
)
1962 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
1964 EXPORT_SYMBOL(scsi_target_quiesce
);
1967 device_resume_fn(struct scsi_device
*sdev
, void *data
)
1969 scsi_device_resume(sdev
);
1973 scsi_target_resume(struct scsi_target
*starget
)
1975 starget_for_each_device(starget
, NULL
, device_resume_fn
);
1977 EXPORT_SYMBOL(scsi_target_resume
);
1980 * scsi_internal_device_block - internal function to put a device
1981 * temporarily into the SDEV_BLOCK state
1982 * @sdev: device to block
1984 * Block request made by scsi lld's to temporarily stop all
1985 * scsi commands on the specified device. Called from interrupt
1986 * or normal process context.
1988 * Returns zero if successful or error if not
1991 * This routine transitions the device to the SDEV_BLOCK state
1992 * (which must be a legal transition). When the device is in this
1993 * state, all commands are deferred until the scsi lld reenables
1994 * the device with scsi_device_unblock or device_block_tmo fires.
1995 * This routine assumes the host_lock is held on entry.
1998 scsi_internal_device_block(struct scsi_device
*sdev
)
2000 request_queue_t
*q
= sdev
->request_queue
;
2001 unsigned long flags
;
2004 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2009 * The device has transitioned to SDEV_BLOCK. Stop the
2010 * block layer from calling the midlayer with this device's
2013 spin_lock_irqsave(q
->queue_lock
, flags
);
2015 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2019 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2022 * scsi_internal_device_unblock - resume a device after a block request
2023 * @sdev: device to resume
2025 * Called by scsi lld's or the midlayer to restart the device queue
2026 * for the previously suspended scsi device. Called from interrupt or
2027 * normal process context.
2029 * Returns zero if successful or error if not.
2032 * This routine transitions the device to the SDEV_RUNNING state
2033 * (which must be a legal transition) allowing the midlayer to
2034 * goose the queue for this device. This routine assumes the
2035 * host_lock is held upon entry.
2038 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2040 request_queue_t
*q
= sdev
->request_queue
;
2042 unsigned long flags
;
2045 * Try to transition the scsi device to SDEV_RUNNING
2046 * and goose the device queue if successful.
2048 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2052 spin_lock_irqsave(q
->queue_lock
, flags
);
2054 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2058 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2061 device_block(struct scsi_device
*sdev
, void *data
)
2063 scsi_internal_device_block(sdev
);
2067 target_block(struct device
*dev
, void *data
)
2069 if (scsi_is_target_device(dev
))
2070 starget_for_each_device(to_scsi_target(dev
), NULL
,
2076 scsi_target_block(struct device
*dev
)
2078 if (scsi_is_target_device(dev
))
2079 starget_for_each_device(to_scsi_target(dev
), NULL
,
2082 device_for_each_child(dev
, NULL
, target_block
);
2084 EXPORT_SYMBOL_GPL(scsi_target_block
);
2087 device_unblock(struct scsi_device
*sdev
, void *data
)
2089 scsi_internal_device_unblock(sdev
);
2093 target_unblock(struct device
*dev
, void *data
)
2095 if (scsi_is_target_device(dev
))
2096 starget_for_each_device(to_scsi_target(dev
), NULL
,
2102 scsi_target_unblock(struct device
*dev
)
2104 if (scsi_is_target_device(dev
))
2105 starget_for_each_device(to_scsi_target(dev
), NULL
,
2108 device_for_each_child(dev
, NULL
, target_unblock
);
2110 EXPORT_SYMBOL_GPL(scsi_target_unblock
);