2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
10 #include <linux/bio.h>
11 #include <linux/blkdev.h>
12 #include <linux/completion.h>
13 #include <linux/kernel.h>
14 #include <linux/mempool.h>
15 #include <linux/slab.h>
16 #include <linux/init.h>
17 #include <linux/pci.h>
18 #include <linux/delay.h>
19 #include <linux/hardirq.h>
21 #include <scsi/scsi.h>
22 #include <scsi/scsi_cmnd.h>
23 #include <scsi/scsi_dbg.h>
24 #include <scsi/scsi_device.h>
25 #include <scsi/scsi_driver.h>
26 #include <scsi/scsi_eh.h>
27 #include <scsi/scsi_host.h>
29 #include "scsi_priv.h"
30 #include "scsi_logging.h"
33 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
34 #define SG_MEMPOOL_SIZE 32
36 struct scsi_host_sg_pool {
43 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
44 #error SCSI_MAX_PHYS_SEGMENTS is too small
47 #define SP(x) { x, "sgpool-" #x }
48 static struct scsi_host_sg_pool scsi_sg_pools[] = {
52 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
54 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
56 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
58 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
59 #error SCSI_MAX_PHYS_SEGMENTS is too large
67 static void scsi_run_queue(struct request_queue *q);
70 * Function: scsi_unprep_request()
72 * Purpose: Remove all preparation done for a request, including its
73 * associated scsi_cmnd, so that it can be requeued.
75 * Arguments: req - request to unprepare
77 * Lock status: Assumed that no locks are held upon entry.
81 static void scsi_unprep_request(struct request *req)
83 struct scsi_cmnd *cmd = req->special;
85 req->flags &= ~REQ_DONTPREP;
88 scsi_put_command(cmd);
92 * Function: scsi_queue_insert()
94 * Purpose: Insert a command in the midlevel queue.
96 * Arguments: cmd - command that we are adding to queue.
97 * reason - why we are inserting command to queue.
99 * Lock status: Assumed that lock is not held upon entry.
103 * Notes: We do this for one of two cases. Either the host is busy
104 * and it cannot accept any more commands for the time being,
105 * or the device returned QUEUE_FULL and can accept no more
107 * Notes: This could be called either from an interrupt context or a
108 * normal process context.
110 int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
112 struct Scsi_Host *host = cmd->device->host;
113 struct scsi_device *device = cmd->device;
114 struct request_queue *q = device->request_queue;
118 printk("Inserting command %p into mlqueue\n", cmd));
121 * Set the appropriate busy bit for the device/host.
123 * If the host/device isn't busy, assume that something actually
124 * completed, and that we should be able to queue a command now.
126 * Note that the prior mid-layer assumption that any host could
127 * always queue at least one command is now broken. The mid-layer
128 * will implement a user specifiable stall (see
129 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
130 * if a command is requeued with no other commands outstanding
131 * either for the device or for the host.
133 if (reason == SCSI_MLQUEUE_HOST_BUSY)
134 host->host_blocked = host->max_host_blocked;
135 else if (reason == SCSI_MLQUEUE_DEVICE_BUSY)
136 device->device_blocked = device->max_device_blocked;
139 * Decrement the counters, since these commands are no longer
140 * active on the host/device.
142 scsi_device_unbusy(device);
145 * Requeue this command. It will go before all other commands
146 * that are already in the queue.
148 * NOTE: there is magic here about the way the queue is plugged if
149 * we have no outstanding commands.
151 * Although we *don't* plug the queue, we call the request
152 * function. The SCSI request function detects the blocked condition
153 * and plugs the queue appropriately.
155 spin_lock_irqsave(q->queue_lock, flags);
156 blk_requeue_request(q, cmd->request);
157 spin_unlock_irqrestore(q->queue_lock, flags);
165 * scsi_execute - insert request and wait for the result
168 * @data_direction: data direction
169 * @buffer: data buffer
170 * @bufflen: len of buffer
171 * @sense: optional sense buffer
172 * @timeout: request timeout in seconds
173 * @retries: number of times to retry request
174 * @flags: or into request flags;
176 * returns the req->errors value which is the the scsi_cmnd result
179 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
180 int data_direction, void *buffer, unsigned bufflen,
181 unsigned char *sense, int timeout, int retries, int flags)
184 int write = (data_direction == DMA_TO_DEVICE);
185 int ret = DRIVER_ERROR << 24;
187 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
189 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
190 buffer, bufflen, __GFP_WAIT))
193 req->cmd_len = COMMAND_SIZE(cmd[0]);
194 memcpy(req->cmd, cmd, req->cmd_len);
197 req->retries = retries;
198 req->timeout = timeout;
199 req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET;
202 * head injection *required* here otherwise quiesce won't work
204 blk_execute_rq(req->q, NULL, req, 1);
208 blk_put_request(req);
212 EXPORT_SYMBOL(scsi_execute);
215 int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
216 int data_direction, void *buffer, unsigned bufflen,
217 struct scsi_sense_hdr *sshdr, int timeout, int retries)
223 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
225 return DRIVER_ERROR << 24;
227 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
228 sense, timeout, retries, 0);
230 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
235 EXPORT_SYMBOL(scsi_execute_req);
237 struct scsi_io_context {
239 void (*done)(void *data, char *sense, int result, int resid);
240 char sense[SCSI_SENSE_BUFFERSIZE];
243 static kmem_cache_t *scsi_io_context_cache;
245 static void scsi_end_async(struct request *req, int uptodate)
247 struct scsi_io_context *sioc = req->end_io_data;
250 sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
252 kmem_cache_free(scsi_io_context_cache, sioc);
253 __blk_put_request(req->q, req);
256 static int scsi_merge_bio(struct request *rq, struct bio *bio)
258 struct request_queue *q = rq->q;
260 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
261 if (rq_data_dir(rq) == WRITE)
262 bio->bi_rw |= (1 << BIO_RW);
263 blk_queue_bounce(q, &bio);
266 blk_rq_bio_prep(q, rq, bio);
267 else if (!q->back_merge_fn(q, rq, bio))
270 rq->biotail->bi_next = bio;
272 rq->hard_nr_sectors += bio_sectors(bio);
273 rq->nr_sectors = rq->hard_nr_sectors;
279 static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error)
289 * scsi_req_map_sg - map a scatterlist into a request
290 * @rq: request to fill
292 * @nsegs: number of elements
293 * @bufflen: len of buffer
294 * @gfp: memory allocation flags
296 * scsi_req_map_sg maps a scatterlist into a request so that the
297 * request can be sent to the block layer. We do not trust the scatterlist
298 * sent to use, as some ULDs use that struct to only organize the pages.
300 static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
301 int nsegs, unsigned bufflen, gfp_t gfp)
303 struct request_queue *q = rq->q;
304 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
305 unsigned int data_len = 0, len, bytes, off;
307 struct bio *bio = NULL;
308 int i, err, nr_vecs = 0;
310 for (i = 0; i < nsegs; i++) {
317 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
320 nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
323 bio = bio_alloc(gfp, nr_vecs);
328 bio->bi_end_io = scsi_bi_endio;
331 if (bio_add_pc_page(q, bio, page, bytes, off) !=
338 if (bio->bi_vcnt >= nr_vecs) {
339 err = scsi_merge_bio(rq, bio);
341 bio_endio(bio, bio->bi_size, 0);
353 rq->buffer = rq->data = NULL;
354 rq->data_len = data_len;
358 while ((bio = rq->bio) != NULL) {
359 rq->bio = bio->bi_next;
361 * call endio instead of bio_put incase it was bounced
363 bio_endio(bio, bio->bi_size, 0);
370 * scsi_execute_async - insert request
373 * @cmd_len: length of scsi cdb
374 * @data_direction: data direction
375 * @buffer: data buffer (this can be a kernel buffer or scatterlist)
376 * @bufflen: len of buffer
377 * @use_sg: if buffer is a scatterlist this is the number of elements
378 * @timeout: request timeout in seconds
379 * @retries: number of times to retry request
380 * @flags: or into request flags
382 int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
383 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
384 int use_sg, int timeout, int retries, void *privdata,
385 void (*done)(void *, char *, int, int), gfp_t gfp)
388 struct scsi_io_context *sioc;
390 int write = (data_direction == DMA_TO_DEVICE);
392 sioc = kmem_cache_alloc(scsi_io_context_cache, gfp);
394 return DRIVER_ERROR << 24;
395 memset(sioc, 0, sizeof(*sioc));
397 req = blk_get_request(sdev->request_queue, write, gfp);
400 req->flags |= REQ_BLOCK_PC | REQ_QUIET;
403 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
405 err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
410 req->cmd_len = cmd_len;
411 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
412 memcpy(req->cmd, cmd, req->cmd_len);
413 req->sense = sioc->sense;
415 req->timeout = timeout;
416 req->retries = retries;
417 req->end_io_data = sioc;
419 sioc->data = privdata;
422 blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
426 blk_put_request(req);
429 return DRIVER_ERROR << 24;
431 EXPORT_SYMBOL_GPL(scsi_execute_async);
434 * Function: scsi_init_cmd_errh()
436 * Purpose: Initialize cmd fields related to error handling.
438 * Arguments: cmd - command that is ready to be queued.
440 * Notes: This function has the job of initializing a number of
441 * fields related to error handling. Typically this will
442 * be called once for each command, as required.
444 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
446 cmd->serial_number = 0;
447 memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer);
448 if (cmd->cmd_len == 0)
449 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
452 void scsi_device_unbusy(struct scsi_device *sdev)
454 struct Scsi_Host *shost = sdev->host;
457 spin_lock_irqsave(shost->host_lock, flags);
459 if (unlikely(scsi_host_in_recovery(shost) &&
460 (shost->host_failed || shost->host_eh_scheduled)))
461 scsi_eh_wakeup(shost);
462 spin_unlock(shost->host_lock);
463 spin_lock(sdev->request_queue->queue_lock);
465 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
469 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
470 * and call blk_run_queue for all the scsi_devices on the target -
471 * including current_sdev first.
473 * Called with *no* scsi locks held.
475 static void scsi_single_lun_run(struct scsi_device *current_sdev)
477 struct Scsi_Host *shost = current_sdev->host;
478 struct scsi_device *sdev, *tmp;
479 struct scsi_target *starget = scsi_target(current_sdev);
482 spin_lock_irqsave(shost->host_lock, flags);
483 starget->starget_sdev_user = NULL;
484 spin_unlock_irqrestore(shost->host_lock, flags);
487 * Call blk_run_queue for all LUNs on the target, starting with
488 * current_sdev. We race with others (to set starget_sdev_user),
489 * but in most cases, we will be first. Ideally, each LU on the
490 * target would get some limited time or requests on the target.
492 blk_run_queue(current_sdev->request_queue);
494 spin_lock_irqsave(shost->host_lock, flags);
495 if (starget->starget_sdev_user)
497 list_for_each_entry_safe(sdev, tmp, &starget->devices,
498 same_target_siblings) {
499 if (sdev == current_sdev)
501 if (scsi_device_get(sdev))
504 spin_unlock_irqrestore(shost->host_lock, flags);
505 blk_run_queue(sdev->request_queue);
506 spin_lock_irqsave(shost->host_lock, flags);
508 scsi_device_put(sdev);
511 spin_unlock_irqrestore(shost->host_lock, flags);
515 * Function: scsi_run_queue()
517 * Purpose: Select a proper request queue to serve next
519 * Arguments: q - last request's queue
523 * Notes: The previous command was completely finished, start
524 * a new one if possible.
526 static void scsi_run_queue(struct request_queue *q)
528 struct scsi_device *sdev = q->queuedata;
529 struct Scsi_Host *shost = sdev->host;
532 if (sdev->single_lun)
533 scsi_single_lun_run(sdev);
535 spin_lock_irqsave(shost->host_lock, flags);
536 while (!list_empty(&shost->starved_list) &&
537 !shost->host_blocked && !shost->host_self_blocked &&
538 !((shost->can_queue > 0) &&
539 (shost->host_busy >= shost->can_queue))) {
541 * As long as shost is accepting commands and we have
542 * starved queues, call blk_run_queue. scsi_request_fn
543 * drops the queue_lock and can add us back to the
546 * host_lock protects the starved_list and starved_entry.
547 * scsi_request_fn must get the host_lock before checking
548 * or modifying starved_list or starved_entry.
550 sdev = list_entry(shost->starved_list.next,
551 struct scsi_device, starved_entry);
552 list_del_init(&sdev->starved_entry);
553 spin_unlock_irqrestore(shost->host_lock, flags);
555 blk_run_queue(sdev->request_queue);
557 spin_lock_irqsave(shost->host_lock, flags);
558 if (unlikely(!list_empty(&sdev->starved_entry)))
560 * sdev lost a race, and was put back on the
561 * starved list. This is unlikely but without this
562 * in theory we could loop forever.
566 spin_unlock_irqrestore(shost->host_lock, flags);
572 * Function: scsi_requeue_command()
574 * Purpose: Handle post-processing of completed commands.
576 * Arguments: q - queue to operate on
577 * cmd - command that may need to be requeued.
581 * Notes: After command completion, there may be blocks left
582 * over which weren't finished by the previous command
583 * this can be for a number of reasons - the main one is
584 * I/O errors in the middle of the request, in which case
585 * we need to request the blocks that come after the bad
587 * Notes: Upon return, cmd is a stale pointer.
589 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
591 struct request *req = cmd->request;
594 scsi_unprep_request(req);
595 spin_lock_irqsave(q->queue_lock, flags);
596 blk_requeue_request(q, req);
597 spin_unlock_irqrestore(q->queue_lock, flags);
602 void scsi_next_command(struct scsi_cmnd *cmd)
604 struct scsi_device *sdev = cmd->device;
605 struct request_queue *q = sdev->request_queue;
607 /* need to hold a reference on the device before we let go of the cmd */
608 get_device(&sdev->sdev_gendev);
610 scsi_put_command(cmd);
613 /* ok to remove device now */
614 put_device(&sdev->sdev_gendev);
617 void scsi_run_host_queues(struct Scsi_Host *shost)
619 struct scsi_device *sdev;
621 shost_for_each_device(sdev, shost)
622 scsi_run_queue(sdev->request_queue);
626 * Function: scsi_end_request()
628 * Purpose: Post-processing of completed commands (usually invoked at end
629 * of upper level post-processing and scsi_io_completion).
631 * Arguments: cmd - command that is complete.
632 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
633 * bytes - number of bytes of completed I/O
634 * requeue - indicates whether we should requeue leftovers.
636 * Lock status: Assumed that lock is not held upon entry.
638 * Returns: cmd if requeue required, NULL otherwise.
640 * Notes: This is called for block device requests in order to
641 * mark some number of sectors as complete.
643 * We are guaranteeing that the request queue will be goosed
644 * at some point during this call.
645 * Notes: If cmd was requeued, upon return it will be a stale pointer.
647 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
648 int bytes, int requeue)
650 request_queue_t *q = cmd->device->request_queue;
651 struct request *req = cmd->request;
655 * If there are blocks left over at the end, set up the command
656 * to queue the remainder of them.
658 if (end_that_request_chunk(req, uptodate, bytes)) {
659 int leftover = (req->hard_nr_sectors << 9);
661 if (blk_pc_request(req))
662 leftover = req->data_len;
664 /* kill remainder if no retrys */
665 if (!uptodate && blk_noretry_request(req))
666 end_that_request_chunk(req, 0, leftover);
670 * Bleah. Leftovers again. Stick the
671 * leftovers in the front of the
672 * queue, and goose the queue again.
674 scsi_requeue_command(q, cmd);
681 add_disk_randomness(req->rq_disk);
683 spin_lock_irqsave(q->queue_lock, flags);
684 if (blk_rq_tagged(req))
685 blk_queue_end_tag(q, req);
686 end_that_request_last(req, uptodate);
687 spin_unlock_irqrestore(q->queue_lock, flags);
690 * This will goose the queue request function at the end, so we don't
691 * need to worry about launching another command.
693 scsi_next_command(cmd);
697 static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
699 struct scsi_host_sg_pool *sgp;
700 struct scatterlist *sgl;
702 BUG_ON(!cmd->use_sg);
704 switch (cmd->use_sg) {
714 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
718 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
722 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
733 sgp = scsi_sg_pools + cmd->sglist_len;
734 sgl = mempool_alloc(sgp->pool, gfp_mask);
738 static void scsi_free_sgtable(struct scatterlist *sgl, int index)
740 struct scsi_host_sg_pool *sgp;
742 BUG_ON(index >= SG_MEMPOOL_NR);
744 sgp = scsi_sg_pools + index;
745 mempool_free(sgl, sgp->pool);
749 * Function: scsi_release_buffers()
751 * Purpose: Completion processing for block device I/O requests.
753 * Arguments: cmd - command that we are bailing.
755 * Lock status: Assumed that no lock is held upon entry.
759 * Notes: In the event that an upper level driver rejects a
760 * command, we must release resources allocated during
761 * the __init_io() function. Primarily this would involve
762 * the scatter-gather table, and potentially any bounce
765 static void scsi_release_buffers(struct scsi_cmnd *cmd)
768 scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
771 * Zero these out. They now point to freed memory, and it is
772 * dangerous to hang onto the pointers.
774 cmd->request_buffer = NULL;
775 cmd->request_bufflen = 0;
779 * Function: scsi_io_completion()
781 * Purpose: Completion processing for block device I/O requests.
783 * Arguments: cmd - command that is finished.
785 * Lock status: Assumed that no lock is held upon entry.
789 * Notes: This function is matched in terms of capabilities to
790 * the function that created the scatter-gather list.
791 * In other words, if there are no bounce buffers
792 * (the normal case for most drivers), we don't need
793 * the logic to deal with cleaning up afterwards.
795 * We must do one of several things here:
797 * a) Call scsi_end_request. This will finish off the
798 * specified number of sectors. If we are done, the
799 * command block will be released, and the queue
800 * function will be goosed. If we are not done, then
801 * scsi_end_request will directly goose the queue.
803 * b) We can just use scsi_requeue_command() here. This would
804 * be used if we just wanted to retry, for example.
806 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
808 int result = cmd->result;
809 int this_count = cmd->request_bufflen;
810 request_queue_t *q = cmd->device->request_queue;
811 struct request *req = cmd->request;
812 int clear_errors = 1;
813 struct scsi_sense_hdr sshdr;
815 int sense_deferred = 0;
817 scsi_release_buffers(cmd);
820 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
822 sense_deferred = scsi_sense_is_deferred(&sshdr);
825 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
826 req->errors = result;
829 if (sense_valid && req->sense) {
831 * SG_IO wants current and deferred errors
833 int len = 8 + cmd->sense_buffer[7];
835 if (len > SCSI_SENSE_BUFFERSIZE)
836 len = SCSI_SENSE_BUFFERSIZE;
837 memcpy(req->sense, cmd->sense_buffer, len);
838 req->sense_len = len;
841 req->data_len = cmd->resid;
845 * Next deal with any sectors which we were able to correctly
848 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
850 req->nr_sectors, good_bytes));
851 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
856 /* A number of bytes were successfully read. If there
857 * are leftovers and there is some kind of error
858 * (result != 0), retry the rest.
860 if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL)
863 /* good_bytes = 0, or (inclusive) there were leftovers and
864 * result = 0, so scsi_end_request couldn't retry.
866 if (sense_valid && !sense_deferred) {
867 switch (sshdr.sense_key) {
869 if (cmd->device->removable) {
870 /* Detected disc change. Set a bit
871 * and quietly refuse further access.
873 cmd->device->changed = 1;
874 scsi_end_request(cmd, 0, this_count, 1);
877 /* Must have been a power glitch, or a
878 * bus reset. Could not have been a
879 * media change, so we just retry the
880 * request and see what happens.
882 scsi_requeue_command(q, cmd);
886 case ILLEGAL_REQUEST:
887 /* If we had an ILLEGAL REQUEST returned, then
888 * we may have performed an unsupported
889 * command. The only thing this should be
890 * would be a ten byte read where only a six
891 * byte read was supported. Also, on a system
892 * where READ CAPACITY failed, we may have
893 * read past the end of the disk.
895 if ((cmd->device->use_10_for_rw &&
896 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
897 (cmd->cmnd[0] == READ_10 ||
898 cmd->cmnd[0] == WRITE_10)) {
899 cmd->device->use_10_for_rw = 0;
900 /* This will cause a retry with a
903 scsi_requeue_command(q, cmd);
906 scsi_end_request(cmd, 0, this_count, 1);
911 /* If the device is in the process of becoming
912 * ready, or has a temporary blockage, retry.
914 if (sshdr.asc == 0x04) {
915 switch (sshdr.ascq) {
916 case 0x01: /* becoming ready */
917 case 0x04: /* format in progress */
918 case 0x05: /* rebuild in progress */
919 case 0x06: /* recalculation in progress */
920 case 0x07: /* operation in progress */
921 case 0x08: /* Long write in progress */
922 case 0x09: /* self test in progress */
923 scsi_requeue_command(q, cmd);
929 if (!(req->flags & REQ_QUIET)) {
930 scmd_printk(KERN_INFO, cmd,
931 "Device not ready: ");
932 scsi_print_sense_hdr("", &sshdr);
934 scsi_end_request(cmd, 0, this_count, 1);
936 case VOLUME_OVERFLOW:
937 if (!(req->flags & REQ_QUIET)) {
938 scmd_printk(KERN_INFO, cmd,
939 "Volume overflow, CDB: ");
940 __scsi_print_command(cmd->cmnd);
941 scsi_print_sense("", cmd);
943 /* See SSC3rXX or current. */
944 scsi_end_request(cmd, 0, this_count, 1);
950 if (host_byte(result) == DID_RESET) {
951 /* Third party bus reset or reset for error recovery
952 * reasons. Just retry the request and see what
955 scsi_requeue_command(q, cmd);
959 if (!(req->flags & REQ_QUIET)) {
960 scmd_printk(KERN_INFO, cmd,
961 "SCSI error: return code = 0x%08x\n",
963 if (driver_byte(result) & DRIVER_SENSE)
964 scsi_print_sense("", cmd);
967 scsi_end_request(cmd, 0, this_count, !result);
969 EXPORT_SYMBOL(scsi_io_completion);
972 * Function: scsi_init_io()
974 * Purpose: SCSI I/O initialize function.
976 * Arguments: cmd - Command descriptor we wish to initialize
978 * Returns: 0 on success
979 * BLKPREP_DEFER if the failure is retryable
980 * BLKPREP_KILL if the failure is fatal
982 static int scsi_init_io(struct scsi_cmnd *cmd)
984 struct request *req = cmd->request;
985 struct scatterlist *sgpnt;
989 * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
991 if ((req->flags & REQ_BLOCK_PC) && !req->bio) {
992 cmd->request_bufflen = req->data_len;
993 cmd->request_buffer = req->data;
994 req->buffer = req->data;
1000 * we used to not use scatter-gather for single segment request,
1001 * but now we do (it makes highmem I/O easier to support without
1004 cmd->use_sg = req->nr_phys_segments;
1007 * if sg table allocation fails, requeue request later.
1009 sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
1010 if (unlikely(!sgpnt)) {
1011 scsi_unprep_request(req);
1012 return BLKPREP_DEFER;
1015 cmd->request_buffer = (char *) sgpnt;
1016 cmd->request_bufflen = req->nr_sectors << 9;
1017 if (blk_pc_request(req))
1018 cmd->request_bufflen = req->data_len;
1022 * Next, walk the list, and fill in the addresses and sizes of
1025 count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
1028 * mapped well, send it off
1030 if (likely(count <= cmd->use_sg)) {
1031 cmd->use_sg = count;
1035 printk(KERN_ERR "Incorrect number of segments after building list\n");
1036 printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg);
1037 printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
1038 req->current_nr_sectors);
1040 /* release the command and kill it */
1041 scsi_release_buffers(cmd);
1042 scsi_put_command(cmd);
1043 return BLKPREP_KILL;
1046 static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk,
1047 sector_t *error_sector)
1049 struct scsi_device *sdev = q->queuedata;
1050 struct scsi_driver *drv;
1052 if (sdev->sdev_state != SDEV_RUNNING)
1055 drv = *(struct scsi_driver **) disk->private_data;
1056 if (drv->issue_flush)
1057 return drv->issue_flush(&sdev->sdev_gendev, error_sector);
1062 static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
1064 BUG_ON(!blk_pc_request(cmd->request));
1066 * This will complete the whole command with uptodate=1 so
1067 * as far as the block layer is concerned the command completed
1068 * successfully. Since this is a REQ_BLOCK_PC command the
1069 * caller should check the request's errors value
1071 scsi_io_completion(cmd, cmd->request_bufflen);
1074 static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd)
1076 struct request *req = cmd->request;
1078 BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
1079 memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd));
1080 cmd->cmd_len = req->cmd_len;
1082 cmd->sc_data_direction = DMA_NONE;
1083 else if (rq_data_dir(req) == WRITE)
1084 cmd->sc_data_direction = DMA_TO_DEVICE;
1086 cmd->sc_data_direction = DMA_FROM_DEVICE;
1088 cmd->transfersize = req->data_len;
1089 cmd->allowed = req->retries;
1090 cmd->timeout_per_command = req->timeout;
1091 cmd->done = scsi_blk_pc_done;
1094 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1096 struct scsi_device *sdev = q->queuedata;
1097 struct scsi_cmnd *cmd;
1098 int specials_only = 0;
1101 * Just check to see if the device is online. If it isn't, we
1102 * refuse to process any commands. The device must be brought
1103 * online before trying any recovery commands
1105 if (unlikely(!scsi_device_online(sdev))) {
1106 sdev_printk(KERN_ERR, sdev,
1107 "rejecting I/O to offline device\n");
1110 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1111 /* OK, we're not in a running state don't prep
1113 if (sdev->sdev_state == SDEV_DEL) {
1114 /* Device is fully deleted, no commands
1115 * at all allowed down */
1116 sdev_printk(KERN_ERR, sdev,
1117 "rejecting I/O to dead device\n");
1120 /* OK, we only allow special commands (i.e. not
1121 * user initiated ones */
1122 specials_only = sdev->sdev_state;
1126 * Find the actual device driver associated with this command.
1127 * The SPECIAL requests are things like character device or
1128 * ioctls, which did not originate from ll_rw_blk. Note that
1129 * the special field is also used to indicate the cmd for
1130 * the remainder of a partially fulfilled request that can
1131 * come up when there is a medium error. We have to treat
1132 * these two cases differently. We differentiate by looking
1133 * at request->cmd, as this tells us the real story.
1135 if (req->flags & REQ_SPECIAL && req->special) {
1137 } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) {
1139 if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) {
1140 if(specials_only == SDEV_QUIESCE ||
1141 specials_only == SDEV_BLOCK)
1144 sdev_printk(KERN_ERR, sdev,
1145 "rejecting I/O to device being removed\n");
1151 * Now try and find a command block that we can use.
1153 if (!req->special) {
1154 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1160 /* pull a tag out of the request if we have one */
1161 cmd->tag = req->tag;
1163 blk_dump_rq_flags(req, "SCSI bad req");
1167 /* note the overloading of req->special. When the tag
1168 * is active it always means cmd. If the tag goes
1169 * back for re-queueing, it may be reset */
1174 * FIXME: drop the lock here because the functions below
1175 * expect to be called without the queue lock held. Also,
1176 * previously, we dequeued the request before dropping the
1177 * lock. We hope REQ_STARTED prevents anything untoward from
1180 if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) {
1184 * This will do a couple of things:
1185 * 1) Fill in the actual SCSI command.
1186 * 2) Fill in any other upper-level specific fields
1189 * If this returns 0, it means that the request failed
1190 * (reading past end of disk, reading offline device,
1191 * etc). This won't actually talk to the device, but
1192 * some kinds of consistency checking may cause the
1193 * request to be rejected immediately.
1197 * This sets up the scatter-gather table (allocating if
1200 ret = scsi_init_io(cmd);
1202 /* For BLKPREP_KILL/DEFER the cmd was released */
1210 * Initialize the actual SCSI command for this request.
1212 if (req->flags & REQ_BLOCK_PC) {
1213 scsi_setup_blk_pc_cmnd(cmd);
1214 } else if (req->rq_disk) {
1215 struct scsi_driver *drv;
1217 drv = *(struct scsi_driver **)req->rq_disk->private_data;
1218 if (unlikely(!drv->init_command(cmd))) {
1219 scsi_release_buffers(cmd);
1220 scsi_put_command(cmd);
1227 * The request is now prepped, no need to come back here
1229 req->flags |= REQ_DONTPREP;
1233 /* If we defer, the elv_next_request() returns NULL, but the
1234 * queue must be restarted, so we plug here if no returning
1235 * command will automatically do that. */
1236 if (sdev->device_busy == 0)
1238 return BLKPREP_DEFER;
1240 req->errors = DID_NO_CONNECT << 16;
1241 return BLKPREP_KILL;
1245 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1248 * Called with the queue_lock held.
1250 static inline int scsi_dev_queue_ready(struct request_queue *q,
1251 struct scsi_device *sdev)
1253 if (sdev->device_busy >= sdev->queue_depth)
1255 if (sdev->device_busy == 0 && sdev->device_blocked) {
1257 * unblock after device_blocked iterates to zero
1259 if (--sdev->device_blocked == 0) {
1261 sdev_printk(KERN_INFO, sdev,
1262 "unblocking device at zero depth\n"));
1268 if (sdev->device_blocked)
1275 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1276 * return 0. We must end up running the queue again whenever 0 is
1277 * returned, else IO can hang.
1279 * Called with host_lock held.
1281 static inline int scsi_host_queue_ready(struct request_queue *q,
1282 struct Scsi_Host *shost,
1283 struct scsi_device *sdev)
1285 if (scsi_host_in_recovery(shost))
1287 if (shost->host_busy == 0 && shost->host_blocked) {
1289 * unblock after host_blocked iterates to zero
1291 if (--shost->host_blocked == 0) {
1293 printk("scsi%d unblocking host at zero depth\n",
1300 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
1301 shost->host_blocked || shost->host_self_blocked) {
1302 if (list_empty(&sdev->starved_entry))
1303 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1307 /* We're OK to process the command, so we can't be starved */
1308 if (!list_empty(&sdev->starved_entry))
1309 list_del_init(&sdev->starved_entry);
1315 * Kill a request for a dead device
1317 static void scsi_kill_request(struct request *req, request_queue_t *q)
1319 struct scsi_cmnd *cmd = req->special;
1320 struct scsi_device *sdev = cmd->device;
1321 struct Scsi_Host *shost = sdev->host;
1323 blkdev_dequeue_request(req);
1325 if (unlikely(cmd == NULL)) {
1326 printk(KERN_CRIT "impossible request in %s.\n",
1331 scsi_init_cmd_errh(cmd);
1332 cmd->result = DID_NO_CONNECT << 16;
1333 atomic_inc(&cmd->device->iorequest_cnt);
1336 * SCSI request completion path will do scsi_device_unbusy(),
1337 * bump busy counts. To bump the counters, we need to dance
1338 * with the locks as normal issue path does.
1340 sdev->device_busy++;
1341 spin_unlock(sdev->request_queue->queue_lock);
1342 spin_lock(shost->host_lock);
1344 spin_unlock(shost->host_lock);
1345 spin_lock(sdev->request_queue->queue_lock);
1350 static void scsi_softirq_done(struct request *rq)
1352 struct scsi_cmnd *cmd = rq->completion_data;
1353 unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
1356 INIT_LIST_HEAD(&cmd->eh_entry);
1358 disposition = scsi_decide_disposition(cmd);
1359 if (disposition != SUCCESS &&
1360 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1361 sdev_printk(KERN_ERR, cmd->device,
1362 "timing out command, waited %lus\n",
1364 disposition = SUCCESS;
1367 scsi_log_completion(cmd, disposition);
1369 switch (disposition) {
1371 scsi_finish_command(cmd);
1374 scsi_retry_command(cmd);
1376 case ADD_TO_MLQUEUE:
1377 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1380 if (!scsi_eh_scmd_add(cmd, 0))
1381 scsi_finish_command(cmd);
1386 * Function: scsi_request_fn()
1388 * Purpose: Main strategy routine for SCSI.
1390 * Arguments: q - Pointer to actual queue.
1394 * Lock status: IO request lock assumed to be held when called.
1396 static void scsi_request_fn(struct request_queue *q)
1398 struct scsi_device *sdev = q->queuedata;
1399 struct Scsi_Host *shost;
1400 struct scsi_cmnd *cmd;
1401 struct request *req;
1404 printk("scsi: killing requests for dead queue\n");
1405 while ((req = elv_next_request(q)) != NULL)
1406 scsi_kill_request(req, q);
1410 if(!get_device(&sdev->sdev_gendev))
1411 /* We must be tearing the block queue down already */
1415 * To start with, we keep looping until the queue is empty, or until
1416 * the host is no longer able to accept any more requests.
1419 while (!blk_queue_plugged(q)) {
1422 * get next queueable request. We do this early to make sure
1423 * that the request is fully prepared even if we cannot
1426 req = elv_next_request(q);
1427 if (!req || !scsi_dev_queue_ready(q, sdev))
1430 if (unlikely(!scsi_device_online(sdev))) {
1431 sdev_printk(KERN_ERR, sdev,
1432 "rejecting I/O to offline device\n");
1433 scsi_kill_request(req, q);
1439 * Remove the request from the request list.
1441 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1442 blkdev_dequeue_request(req);
1443 sdev->device_busy++;
1445 spin_unlock(q->queue_lock);
1447 if (unlikely(cmd == NULL)) {
1448 printk(KERN_CRIT "impossible request in %s.\n"
1449 "please mail a stack trace to "
1450 "linux-scsi@vger.kernel.org",
1454 spin_lock(shost->host_lock);
1456 if (!scsi_host_queue_ready(q, shost, sdev))
1458 if (sdev->single_lun) {
1459 if (scsi_target(sdev)->starget_sdev_user &&
1460 scsi_target(sdev)->starget_sdev_user != sdev)
1462 scsi_target(sdev)->starget_sdev_user = sdev;
1467 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1468 * take the lock again.
1470 spin_unlock_irq(shost->host_lock);
1473 * Finally, initialize any error handling parameters, and set up
1474 * the timers for timeouts.
1476 scsi_init_cmd_errh(cmd);
1479 * Dispatch the command to the low-level driver.
1481 rtn = scsi_dispatch_cmd(cmd);
1482 spin_lock_irq(q->queue_lock);
1484 /* we're refusing the command; because of
1485 * the way locks get dropped, we need to
1486 * check here if plugging is required */
1487 if(sdev->device_busy == 0)
1497 spin_unlock_irq(shost->host_lock);
1500 * lock q, handle tag, requeue req, and decrement device_busy. We
1501 * must return with queue_lock held.
1503 * Decrementing device_busy without checking it is OK, as all such
1504 * cases (host limits or settings) should run the queue at some
1507 spin_lock_irq(q->queue_lock);
1508 blk_requeue_request(q, req);
1509 sdev->device_busy--;
1510 if(sdev->device_busy == 0)
1513 /* must be careful here...if we trigger the ->remove() function
1514 * we cannot be holding the q lock */
1515 spin_unlock_irq(q->queue_lock);
1516 put_device(&sdev->sdev_gendev);
1517 spin_lock_irq(q->queue_lock);
1520 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1522 struct device *host_dev;
1523 u64 bounce_limit = 0xffffffff;
1525 if (shost->unchecked_isa_dma)
1526 return BLK_BOUNCE_ISA;
1528 * Platforms with virtual-DMA translation
1529 * hardware have no practical limit.
1531 if (!PCI_DMA_BUS_IS_PHYS)
1532 return BLK_BOUNCE_ANY;
1534 host_dev = scsi_get_device(shost);
1535 if (host_dev && host_dev->dma_mask)
1536 bounce_limit = *host_dev->dma_mask;
1538 return bounce_limit;
1540 EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1542 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1544 struct Scsi_Host *shost = sdev->host;
1545 struct request_queue *q;
1547 q = blk_init_queue(scsi_request_fn, NULL);
1551 blk_queue_prep_rq(q, scsi_prep_fn);
1553 blk_queue_max_hw_segments(q, shost->sg_tablesize);
1554 blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS);
1555 blk_queue_max_sectors(q, shost->max_sectors);
1556 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1557 blk_queue_segment_boundary(q, shost->dma_boundary);
1558 blk_queue_issue_flush_fn(q, scsi_issue_flush_fn);
1559 blk_queue_softirq_done(q, scsi_softirq_done);
1561 if (!shost->use_clustering)
1562 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
1566 void scsi_free_queue(struct request_queue *q)
1568 blk_cleanup_queue(q);
1572 * Function: scsi_block_requests()
1574 * Purpose: Utility function used by low-level drivers to prevent further
1575 * commands from being queued to the device.
1577 * Arguments: shost - Host in question
1581 * Lock status: No locks are assumed held.
1583 * Notes: There is no timer nor any other means by which the requests
1584 * get unblocked other than the low-level driver calling
1585 * scsi_unblock_requests().
1587 void scsi_block_requests(struct Scsi_Host *shost)
1589 shost->host_self_blocked = 1;
1591 EXPORT_SYMBOL(scsi_block_requests);
1594 * Function: scsi_unblock_requests()
1596 * Purpose: Utility function used by low-level drivers to allow further
1597 * commands from being queued to the device.
1599 * Arguments: shost - Host in question
1603 * Lock status: No locks are assumed held.
1605 * Notes: There is no timer nor any other means by which the requests
1606 * get unblocked other than the low-level driver calling
1607 * scsi_unblock_requests().
1609 * This is done as an API function so that changes to the
1610 * internals of the scsi mid-layer won't require wholesale
1611 * changes to drivers that use this feature.
1613 void scsi_unblock_requests(struct Scsi_Host *shost)
1615 shost->host_self_blocked = 0;
1616 scsi_run_host_queues(shost);
1618 EXPORT_SYMBOL(scsi_unblock_requests);
1620 int __init scsi_init_queue(void)
1624 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1625 sizeof(struct scsi_io_context),
1627 if (!scsi_io_context_cache) {
1628 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1632 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1633 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1634 int size = sgp->size * sizeof(struct scatterlist);
1636 sgp->slab = kmem_cache_create(sgp->name, size, 0,
1637 SLAB_HWCACHE_ALIGN, NULL, NULL);
1639 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1643 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1646 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1654 void scsi_exit_queue(void)
1658 kmem_cache_destroy(scsi_io_context_cache);
1660 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1661 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1662 mempool_destroy(sgp->pool);
1663 kmem_cache_destroy(sgp->slab);
1668 * scsi_mode_select - issue a mode select
1669 * @sdev: SCSI device to be queried
1670 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1671 * @sp: Save page bit (0 == don't save, 1 == save)
1672 * @modepage: mode page being requested
1673 * @buffer: request buffer (may not be smaller than eight bytes)
1674 * @len: length of request buffer.
1675 * @timeout: command timeout
1676 * @retries: number of retries before failing
1677 * @data: returns a structure abstracting the mode header data
1678 * @sense: place to put sense data (or NULL if no sense to be collected).
1679 * must be SCSI_SENSE_BUFFERSIZE big.
1681 * Returns zero if successful; negative error number or scsi
1686 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1687 unsigned char *buffer, int len, int timeout, int retries,
1688 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1690 unsigned char cmd[10];
1691 unsigned char *real_buffer;
1694 memset(cmd, 0, sizeof(cmd));
1695 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1697 if (sdev->use_10_for_ms) {
1700 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1703 memcpy(real_buffer + 8, buffer, len);
1707 real_buffer[2] = data->medium_type;
1708 real_buffer[3] = data->device_specific;
1709 real_buffer[4] = data->longlba ? 0x01 : 0;
1711 real_buffer[6] = data->block_descriptor_length >> 8;
1712 real_buffer[7] = data->block_descriptor_length;
1714 cmd[0] = MODE_SELECT_10;
1718 if (len > 255 || data->block_descriptor_length > 255 ||
1722 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1725 memcpy(real_buffer + 4, buffer, len);
1728 real_buffer[1] = data->medium_type;
1729 real_buffer[2] = data->device_specific;
1730 real_buffer[3] = data->block_descriptor_length;
1733 cmd[0] = MODE_SELECT;
1737 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1738 sshdr, timeout, retries);
1742 EXPORT_SYMBOL_GPL(scsi_mode_select);
1745 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1746 * six bytes if necessary.
1747 * @sdev: SCSI device to be queried
1748 * @dbd: set if mode sense will allow block descriptors to be returned
1749 * @modepage: mode page being requested
1750 * @buffer: request buffer (may not be smaller than eight bytes)
1751 * @len: length of request buffer.
1752 * @timeout: command timeout
1753 * @retries: number of retries before failing
1754 * @data: returns a structure abstracting the mode header data
1755 * @sense: place to put sense data (or NULL if no sense to be collected).
1756 * must be SCSI_SENSE_BUFFERSIZE big.
1758 * Returns zero if unsuccessful, or the header offset (either 4
1759 * or 8 depending on whether a six or ten byte command was
1760 * issued) if successful.
1763 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
1764 unsigned char *buffer, int len, int timeout, int retries,
1765 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1767 unsigned char cmd[12];
1771 struct scsi_sense_hdr my_sshdr;
1773 memset(data, 0, sizeof(*data));
1774 memset(&cmd[0], 0, 12);
1775 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1778 /* caller might not be interested in sense, but we need it */
1783 use_10_for_ms = sdev->use_10_for_ms;
1785 if (use_10_for_ms) {
1789 cmd[0] = MODE_SENSE_10;
1796 cmd[0] = MODE_SENSE;
1801 memset(buffer, 0, len);
1803 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1804 sshdr, timeout, retries);
1806 /* This code looks awful: what it's doing is making sure an
1807 * ILLEGAL REQUEST sense return identifies the actual command
1808 * byte as the problem. MODE_SENSE commands can return
1809 * ILLEGAL REQUEST if the code page isn't supported */
1811 if (use_10_for_ms && !scsi_status_is_good(result) &&
1812 (driver_byte(result) & DRIVER_SENSE)) {
1813 if (scsi_sense_valid(sshdr)) {
1814 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1815 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
1817 * Invalid command operation code
1819 sdev->use_10_for_ms = 0;
1825 if(scsi_status_is_good(result)) {
1826 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1827 (modepage == 6 || modepage == 8))) {
1828 /* Initio breakage? */
1831 data->medium_type = 0;
1832 data->device_specific = 0;
1834 data->block_descriptor_length = 0;
1835 } else if(use_10_for_ms) {
1836 data->length = buffer[0]*256 + buffer[1] + 2;
1837 data->medium_type = buffer[2];
1838 data->device_specific = buffer[3];
1839 data->longlba = buffer[4] & 0x01;
1840 data->block_descriptor_length = buffer[6]*256
1843 data->length = buffer[0] + 1;
1844 data->medium_type = buffer[1];
1845 data->device_specific = buffer[2];
1846 data->block_descriptor_length = buffer[3];
1848 data->header_length = header_length;
1853 EXPORT_SYMBOL(scsi_mode_sense);
1856 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries)
1859 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1861 struct scsi_sense_hdr sshdr;
1864 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr,
1867 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
1869 if ((scsi_sense_valid(&sshdr)) &&
1870 ((sshdr.sense_key == UNIT_ATTENTION) ||
1871 (sshdr.sense_key == NOT_READY))) {
1878 EXPORT_SYMBOL(scsi_test_unit_ready);
1881 * scsi_device_set_state - Take the given device through the device
1883 * @sdev: scsi device to change the state of.
1884 * @state: state to change to.
1886 * Returns zero if unsuccessful or an error if the requested
1887 * transition is illegal.
1890 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
1892 enum scsi_device_state oldstate = sdev->sdev_state;
1894 if (state == oldstate)
1899 /* There are no legal states that come back to
1900 * created. This is the manually initialised start
1974 sdev->sdev_state = state;
1978 SCSI_LOG_ERROR_RECOVERY(1,
1979 sdev_printk(KERN_ERR, sdev,
1980 "Illegal state transition %s->%s\n",
1981 scsi_device_state_name(oldstate),
1982 scsi_device_state_name(state))
1986 EXPORT_SYMBOL(scsi_device_set_state);
1989 * scsi_device_quiesce - Block user issued commands.
1990 * @sdev: scsi device to quiesce.
1992 * This works by trying to transition to the SDEV_QUIESCE state
1993 * (which must be a legal transition). When the device is in this
1994 * state, only special requests will be accepted, all others will
1995 * be deferred. Since special requests may also be requeued requests,
1996 * a successful return doesn't guarantee the device will be
1997 * totally quiescent.
1999 * Must be called with user context, may sleep.
2001 * Returns zero if unsuccessful or an error if not.
2004 scsi_device_quiesce(struct scsi_device *sdev)
2006 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2010 scsi_run_queue(sdev->request_queue);
2011 while (sdev->device_busy) {
2012 msleep_interruptible(200);
2013 scsi_run_queue(sdev->request_queue);
2017 EXPORT_SYMBOL(scsi_device_quiesce);
2020 * scsi_device_resume - Restart user issued commands to a quiesced device.
2021 * @sdev: scsi device to resume.
2023 * Moves the device from quiesced back to running and restarts the
2026 * Must be called with user context, may sleep.
2029 scsi_device_resume(struct scsi_device *sdev)
2031 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2033 scsi_run_queue(sdev->request_queue);
2035 EXPORT_SYMBOL(scsi_device_resume);
2038 device_quiesce_fn(struct scsi_device *sdev, void *data)
2040 scsi_device_quiesce(sdev);
2044 scsi_target_quiesce(struct scsi_target *starget)
2046 starget_for_each_device(starget, NULL, device_quiesce_fn);
2048 EXPORT_SYMBOL(scsi_target_quiesce);
2051 device_resume_fn(struct scsi_device *sdev, void *data)
2053 scsi_device_resume(sdev);
2057 scsi_target_resume(struct scsi_target *starget)
2059 starget_for_each_device(starget, NULL, device_resume_fn);
2061 EXPORT_SYMBOL(scsi_target_resume);
2064 * scsi_internal_device_block - internal function to put a device
2065 * temporarily into the SDEV_BLOCK state
2066 * @sdev: device to block
2068 * Block request made by scsi lld's to temporarily stop all
2069 * scsi commands on the specified device. Called from interrupt
2070 * or normal process context.
2072 * Returns zero if successful or error if not
2075 * This routine transitions the device to the SDEV_BLOCK state
2076 * (which must be a legal transition). When the device is in this
2077 * state, all commands are deferred until the scsi lld reenables
2078 * the device with scsi_device_unblock or device_block_tmo fires.
2079 * This routine assumes the host_lock is held on entry.
2082 scsi_internal_device_block(struct scsi_device *sdev)
2084 request_queue_t *q = sdev->request_queue;
2085 unsigned long flags;
2088 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2093 * The device has transitioned to SDEV_BLOCK. Stop the
2094 * block layer from calling the midlayer with this device's
2097 spin_lock_irqsave(q->queue_lock, flags);
2099 spin_unlock_irqrestore(q->queue_lock, flags);
2103 EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2106 * scsi_internal_device_unblock - resume a device after a block request
2107 * @sdev: device to resume
2109 * Called by scsi lld's or the midlayer to restart the device queue
2110 * for the previously suspended scsi device. Called from interrupt or
2111 * normal process context.
2113 * Returns zero if successful or error if not.
2116 * This routine transitions the device to the SDEV_RUNNING state
2117 * (which must be a legal transition) allowing the midlayer to
2118 * goose the queue for this device. This routine assumes the
2119 * host_lock is held upon entry.
2122 scsi_internal_device_unblock(struct scsi_device *sdev)
2124 request_queue_t *q = sdev->request_queue;
2126 unsigned long flags;
2129 * Try to transition the scsi device to SDEV_RUNNING
2130 * and goose the device queue if successful.
2132 err = scsi_device_set_state(sdev, SDEV_RUNNING);
2136 spin_lock_irqsave(q->queue_lock, flags);
2138 spin_unlock_irqrestore(q->queue_lock, flags);
2142 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2145 device_block(struct scsi_device *sdev, void *data)
2147 scsi_internal_device_block(sdev);
2151 target_block(struct device *dev, void *data)
2153 if (scsi_is_target_device(dev))
2154 starget_for_each_device(to_scsi_target(dev), NULL,
2160 scsi_target_block(struct device *dev)
2162 if (scsi_is_target_device(dev))
2163 starget_for_each_device(to_scsi_target(dev), NULL,
2166 device_for_each_child(dev, NULL, target_block);
2168 EXPORT_SYMBOL_GPL(scsi_target_block);
2171 device_unblock(struct scsi_device *sdev, void *data)
2173 scsi_internal_device_unblock(sdev);
2177 target_unblock(struct device *dev, void *data)
2179 if (scsi_is_target_device(dev))
2180 starget_for_each_device(to_scsi_target(dev), NULL,
2186 scsi_target_unblock(struct device *dev)
2188 if (scsi_is_target_device(dev))
2189 starget_for_each_device(to_scsi_target(dev), NULL,
2192 device_for_each_child(dev, NULL, target_unblock);
2194 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2197 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2198 * @sg: scatter-gather list
2199 * @sg_count: number of segments in sg
2200 * @offset: offset in bytes into sg, on return offset into the mapped area
2201 * @len: bytes to map, on return number of bytes mapped
2203 * Returns virtual address of the start of the mapped page
2205 void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
2206 size_t *offset, size_t *len)
2209 size_t sg_len = 0, len_complete = 0;
2212 for (i = 0; i < sg_count; i++) {
2213 len_complete = sg_len; /* Complete sg-entries */
2214 sg_len += sg[i].length;
2215 if (sg_len > *offset)
2219 if (unlikely(i == sg_count)) {
2220 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2222 __FUNCTION__, sg_len, *offset, sg_count);
2227 /* Offset starting from the beginning of first page in this sg-entry */
2228 *offset = *offset - len_complete + sg[i].offset;
2230 /* Assumption: contiguous pages can be accessed as "page + i" */
2231 page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));
2232 *offset &= ~PAGE_MASK;
2234 /* Bytes in this sg-entry from *offset to the end of the page */
2235 sg_len = PAGE_SIZE - *offset;
2239 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2241 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2244 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
2245 * mapped with scsi_kmap_atomic_sg
2246 * @virt: virtual address to be unmapped
2248 void scsi_kunmap_atomic_sg(void *virt)
2250 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2252 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);