2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
12 * Bug correction thanks go to :
13 * Rik Faith <faith@cs.unc.edu>
14 * Tommy Thorn <tthorn>
15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 * add scatter-gather, multiple outstanding request, and other
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
24 * Added request_module("scsi_hostadapter") for kerneld:
25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 * Bjorn Ekwall <bj0rn@blox.se>
29 * Major improvements to the timeout, abort, and reset processing,
30 * as well as performance modifications for large queue depths by
31 * Leonard N. Zubkoff <lnz@dandelion.com>
33 * Converted cli() code to spinlocks, Ingo Molnar
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 * out_of_space hacks, D. Gilbert (dpg) 990608
40 #include <linux/module.h>
41 #include <linux/moduleparam.h>
42 #include <linux/kernel.h>
43 #include <linux/timer.h>
44 #include <linux/string.h>
45 #include <linux/slab.h>
46 #include <linux/blkdev.h>
47 #include <linux/delay.h>
48 #include <linux/init.h>
49 #include <linux/completion.h>
50 #include <linux/unistd.h>
51 #include <linux/spinlock.h>
52 #include <linux/kmod.h>
53 #include <linux/interrupt.h>
54 #include <linux/notifier.h>
55 #include <linux/cpu.h>
56 #include <linux/mutex.h>
57 #include <linux/async.h>
58 #include <asm/unaligned.h>
60 #include <scsi/scsi.h>
61 #include <scsi/scsi_cmnd.h>
62 #include <scsi/scsi_dbg.h>
63 #include <scsi/scsi_device.h>
64 #include <scsi/scsi_driver.h>
65 #include <scsi/scsi_eh.h>
66 #include <scsi/scsi_host.h>
67 #include <scsi/scsi_tcq.h>
69 #include "scsi_priv.h"
70 #include "scsi_logging.h"
72 #define CREATE_TRACE_POINTS
73 #include <trace/events/scsi.h>
75 static void scsi_done(struct scsi_cmnd *cmd);
78 * Definitions and constants.
82 * Note - the initial logging level can be set here to log events at boot time.
83 * After the system is up, you may enable logging via the /proc interface.
85 unsigned int scsi_logging_level;
86 #if defined(CONFIG_SCSI_LOGGING)
87 EXPORT_SYMBOL(scsi_logging_level);
90 /* sd, scsi core and power management need to coordinate flushing async actions */
91 ASYNC_DOMAIN(scsi_sd_probe_domain);
92 EXPORT_SYMBOL(scsi_sd_probe_domain);
94 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
95 * You may not alter any existing entry (although adding new ones is
96 * encouraged once assigned by ANSI/INCITS T10
98 static const char *const scsi_device_types[] = {
121 * scsi_device_type - Return 17 char string indicating device type.
122 * @type: type number to look up
125 const char * scsi_device_type(unsigned type)
128 return "Well-known LUN ";
131 if (type >= ARRAY_SIZE(scsi_device_types))
133 return scsi_device_types[type];
136 EXPORT_SYMBOL(scsi_device_type);
138 struct scsi_host_cmd_pool {
139 struct kmem_cache *cmd_slab;
140 struct kmem_cache *sense_slab;
144 unsigned int slab_flags;
148 static struct scsi_host_cmd_pool scsi_cmd_pool = {
149 .cmd_name = "scsi_cmd_cache",
150 .sense_name = "scsi_sense_cache",
151 .slab_flags = SLAB_HWCACHE_ALIGN,
154 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
155 .cmd_name = "scsi_cmd_cache(DMA)",
156 .sense_name = "scsi_sense_cache(DMA)",
157 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
158 .gfp_mask = __GFP_DMA,
161 static DEFINE_MUTEX(host_cmd_pool_mutex);
164 * scsi_pool_alloc_command - internal function to get a fully allocated command
165 * @pool: slab pool to allocate the command from
166 * @gfp_mask: mask for the allocation
168 * Returns a fully allocated command (with the allied sense buffer) or
171 static struct scsi_cmnd *
172 scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
174 struct scsi_cmnd *cmd;
176 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
180 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
181 gfp_mask | pool->gfp_mask);
182 if (!cmd->sense_buffer) {
183 kmem_cache_free(pool->cmd_slab, cmd);
191 * scsi_pool_free_command - internal function to release a command
192 * @pool: slab pool to allocate the command from
193 * @cmd: command to release
195 * the command must previously have been allocated by
196 * scsi_pool_alloc_command.
199 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
200 struct scsi_cmnd *cmd)
203 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
205 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
206 kmem_cache_free(pool->cmd_slab, cmd);
210 * scsi_host_alloc_command - internal function to allocate command
211 * @shost: SCSI host whose pool to allocate from
212 * @gfp_mask: mask for the allocation
214 * Returns a fully allocated command with sense buffer and protection
215 * data buffer (where applicable) or NULL on failure
217 static struct scsi_cmnd *
218 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
220 struct scsi_cmnd *cmd;
222 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
226 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
227 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
229 if (!cmd->prot_sdb) {
230 scsi_pool_free_command(shost->cmd_pool, cmd);
239 * __scsi_get_command - Allocate a struct scsi_cmnd
240 * @shost: host to transmit command
241 * @gfp_mask: allocation mask
243 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
244 * host's free_list if necessary.
246 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
248 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
250 if (unlikely(!cmd)) {
253 spin_lock_irqsave(&shost->free_list_lock, flags);
254 if (likely(!list_empty(&shost->free_list))) {
255 cmd = list_entry(shost->free_list.next,
256 struct scsi_cmnd, list);
257 list_del_init(&cmd->list);
259 spin_unlock_irqrestore(&shost->free_list_lock, flags);
264 buf = cmd->sense_buffer;
265 prot = cmd->prot_sdb;
267 memset(cmd, 0, sizeof(*cmd));
269 cmd->sense_buffer = buf;
270 cmd->prot_sdb = prot;
276 EXPORT_SYMBOL_GPL(__scsi_get_command);
279 * scsi_get_command - Allocate and setup a scsi command block
280 * @dev: parent scsi device
281 * @gfp_mask: allocator flags
283 * Returns: The allocated scsi command structure.
285 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
287 struct scsi_cmnd *cmd;
289 /* Bail if we can't get a reference to the device */
290 if (!get_device(&dev->sdev_gendev))
293 cmd = __scsi_get_command(dev->host, gfp_mask);
295 if (likely(cmd != NULL)) {
299 INIT_LIST_HEAD(&cmd->list);
300 spin_lock_irqsave(&dev->list_lock, flags);
301 list_add_tail(&cmd->list, &dev->cmd_list);
302 spin_unlock_irqrestore(&dev->list_lock, flags);
303 cmd->jiffies_at_alloc = jiffies;
305 put_device(&dev->sdev_gendev);
309 EXPORT_SYMBOL(scsi_get_command);
312 * __scsi_put_command - Free a struct scsi_cmnd
314 * @cmd: Command to free
315 * @dev: parent scsi device
317 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
322 /* changing locks here, don't need to restore the irq state */
323 spin_lock_irqsave(&shost->free_list_lock, flags);
324 if (unlikely(list_empty(&shost->free_list))) {
325 list_add(&cmd->list, &shost->free_list);
328 spin_unlock_irqrestore(&shost->free_list_lock, flags);
330 if (likely(cmd != NULL))
331 scsi_pool_free_command(shost->cmd_pool, cmd);
335 EXPORT_SYMBOL(__scsi_put_command);
338 * scsi_put_command - Free a scsi command block
339 * @cmd: command block to free
343 * Notes: The command must not belong to any lists.
345 void scsi_put_command(struct scsi_cmnd *cmd)
347 struct scsi_device *sdev = cmd->device;
350 /* serious error if the command hasn't come from a device list */
351 spin_lock_irqsave(&cmd->device->list_lock, flags);
352 BUG_ON(list_empty(&cmd->list));
353 list_del_init(&cmd->list);
354 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
356 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
358 EXPORT_SYMBOL(scsi_put_command);
360 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
362 struct scsi_host_cmd_pool *retval = NULL, *pool;
364 * Select a command slab for this host and create it if not
367 mutex_lock(&host_cmd_pool_mutex);
368 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
371 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
372 sizeof(struct scsi_cmnd), 0,
373 pool->slab_flags, NULL);
377 pool->sense_slab = kmem_cache_create(pool->sense_name,
378 SCSI_SENSE_BUFFERSIZE, 0,
379 pool->slab_flags, NULL);
380 if (!pool->sense_slab) {
381 kmem_cache_destroy(pool->cmd_slab);
389 mutex_unlock(&host_cmd_pool_mutex);
393 static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
395 struct scsi_host_cmd_pool *pool;
397 mutex_lock(&host_cmd_pool_mutex);
398 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
401 * This may happen if a driver has a mismatched get and put
402 * of the command pool; the driver should be implicated in
405 BUG_ON(pool->users == 0);
407 if (!--pool->users) {
408 kmem_cache_destroy(pool->cmd_slab);
409 kmem_cache_destroy(pool->sense_slab);
411 mutex_unlock(&host_cmd_pool_mutex);
415 * scsi_allocate_command - get a fully allocated SCSI command
416 * @gfp_mask: allocation mask
418 * This function is for use outside of the normal host based pools.
419 * It allocates the relevant command and takes an additional reference
420 * on the pool it used. This function *must* be paired with
421 * scsi_free_command which also has the identical mask, otherwise the
422 * free pool counts will eventually go wrong and you'll trigger a bug.
424 * This function should *only* be used by drivers that need a static
425 * command allocation at start of day for internal functions.
427 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
429 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
434 return scsi_pool_alloc_command(pool, gfp_mask);
436 EXPORT_SYMBOL(scsi_allocate_command);
439 * scsi_free_command - free a command allocated by scsi_allocate_command
440 * @gfp_mask: mask used in the original allocation
441 * @cmd: command to free
443 * Note: using the original allocation mask is vital because that's
444 * what determines which command pool we use to free the command. Any
445 * mismatch will cause the system to BUG eventually.
447 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
449 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
452 * this could trigger if the mask to scsi_allocate_command
453 * doesn't match this mask. Otherwise we're guaranteed that this
454 * succeeds because scsi_allocate_command must have taken a reference
459 scsi_pool_free_command(pool, cmd);
461 * scsi_put_host_cmd_pool is called twice; once to release the
462 * reference we took above, and once to release the reference
463 * originally taken by scsi_allocate_command
465 scsi_put_host_cmd_pool(gfp_mask);
466 scsi_put_host_cmd_pool(gfp_mask);
468 EXPORT_SYMBOL(scsi_free_command);
471 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
472 * @shost: host to allocate the freelist for.
474 * Description: The command freelist protects against system-wide out of memory
475 * deadlock by preallocating one SCSI command structure for each host, so the
476 * system can always write to a swap file on a device associated with that host.
480 int scsi_setup_command_freelist(struct Scsi_Host *shost)
482 struct scsi_cmnd *cmd;
483 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
485 spin_lock_init(&shost->free_list_lock);
486 INIT_LIST_HEAD(&shost->free_list);
488 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
490 if (!shost->cmd_pool)
494 * Get one backup command for this host.
496 cmd = scsi_host_alloc_command(shost, gfp_mask);
498 scsi_put_host_cmd_pool(gfp_mask);
499 shost->cmd_pool = NULL;
502 list_add(&cmd->list, &shost->free_list);
507 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
508 * @shost: host whose freelist is going to be destroyed
510 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
513 * If cmd_pool is NULL the free list was not initialized, so
514 * do not attempt to release resources.
516 if (!shost->cmd_pool)
519 while (!list_empty(&shost->free_list)) {
520 struct scsi_cmnd *cmd;
522 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
523 list_del_init(&cmd->list);
524 scsi_pool_free_command(shost->cmd_pool, cmd);
526 shost->cmd_pool = NULL;
527 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
530 #ifdef CONFIG_SCSI_LOGGING
531 void scsi_log_send(struct scsi_cmnd *cmd)
536 * If ML QUEUE log level is greater than or equal to:
538 * 1: nothing (match completion)
540 * 2: log opcode + command of all commands
542 * 3: same as 2 plus dump cmd address
544 * 4: same as 3 plus dump extra junk
546 if (unlikely(scsi_logging_level)) {
547 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
548 SCSI_LOG_MLQUEUE_BITS);
550 scmd_printk(KERN_INFO, cmd, "Send: ");
552 printk("0x%p ", cmd);
554 scsi_print_command(cmd);
556 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
557 " queuecommand 0x%p\n",
558 scsi_sglist(cmd), scsi_bufflen(cmd),
559 cmd->device->host->hostt->queuecommand);
566 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
571 * If ML COMPLETE log level is greater than or equal to:
573 * 1: log disposition, result, opcode + command, and conditionally
574 * sense data for failures or non SUCCESS dispositions.
576 * 2: same as 1 but for all command completions.
578 * 3: same as 2 plus dump cmd address
580 * 4: same as 3 plus dump extra junk
582 if (unlikely(scsi_logging_level)) {
583 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
584 SCSI_LOG_MLCOMPLETE_BITS);
585 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
587 scmd_printk(KERN_INFO, cmd, "Done: ");
589 printk("0x%p ", cmd);
591 * Dump truncated values, so we usually fit within
594 switch (disposition) {
609 * If called via scsi_times_out.
616 scsi_print_result(cmd);
617 scsi_print_command(cmd);
618 if (status_byte(cmd->result) & CHECK_CONDITION)
619 scsi_print_sense("", cmd);
621 scmd_printk(KERN_INFO, cmd,
622 "scsi host busy %d failed %d\n",
623 cmd->device->host->host_busy,
624 cmd->device->host->host_failed);
631 * scsi_cmd_get_serial - Assign a serial number to a command
632 * @host: the scsi host
633 * @cmd: command to assign serial number to
635 * Description: a serial number identifies a request for error recovery
636 * and debugging purposes. Protected by the Host_Lock of host.
638 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
640 cmd->serial_number = host->cmd_serial_number++;
641 if (cmd->serial_number == 0)
642 cmd->serial_number = host->cmd_serial_number++;
644 EXPORT_SYMBOL(scsi_cmd_get_serial);
647 * scsi_dispatch_command - Dispatch a command to the low-level driver.
648 * @cmd: command block we are dispatching.
650 * Return: nonzero return request was rejected and device's queue needs to be
653 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
655 struct Scsi_Host *host = cmd->device->host;
658 atomic_inc(&cmd->device->iorequest_cnt);
660 /* check if the device is still usable */
661 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
662 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
663 * returns an immediate error upwards, and signals
664 * that the device is no longer present */
665 cmd->result = DID_NO_CONNECT << 16;
667 /* return 0 (because the command has been processed) */
671 /* Check to see if the scsi lld made this device blocked. */
672 if (unlikely(scsi_device_blocked(cmd->device))) {
674 * in blocked state, the command is just put back on
675 * the device queue. The suspend state has already
676 * blocked the queue so future requests should not
677 * occur until the device transitions out of the
681 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
683 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
686 * NOTE: rtn is still zero here because we don't need the
687 * queue to be plugged on return (it's already stopped)
693 * If SCSI-2 or lower, store the LUN value in cmnd.
695 if (cmd->device->scsi_level <= SCSI_2 &&
696 cmd->device->scsi_level != SCSI_UNKNOWN) {
697 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
698 (cmd->device->lun << 5 & 0xe0);
704 * Before we queue this command, check if the command
705 * length exceeds what the host adapter can handle.
707 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
709 printk("queuecommand : command too long. "
710 "cdb_size=%d host->max_cmd_len=%d\n",
711 cmd->cmd_len, cmd->device->host->max_cmd_len));
712 cmd->result = (DID_ABORT << 16);
718 if (unlikely(host->shost_state == SHOST_DEL)) {
719 cmd->result = (DID_NO_CONNECT << 16);
722 trace_scsi_dispatch_cmd_start(cmd);
723 cmd->scsi_done = scsi_done;
724 rtn = host->hostt->queuecommand(host, cmd);
728 trace_scsi_dispatch_cmd_error(cmd, rtn);
729 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
730 rtn != SCSI_MLQUEUE_TARGET_BUSY)
731 rtn = SCSI_MLQUEUE_HOST_BUSY;
733 scsi_queue_insert(cmd, rtn);
736 printk("queuecommand : request rejected\n"));
740 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
745 * scsi_done - Enqueue the finished SCSI command into the done queue.
746 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
747 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
749 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
750 * which regains ownership of the SCSI command (de facto) from a LLDD, and
751 * enqueues the command to the done queue for further processing.
753 * This is the producer of the done queue who enqueues at the tail.
755 * This function is interrupt context safe.
757 static void scsi_done(struct scsi_cmnd *cmd)
759 trace_scsi_dispatch_cmd_done(cmd);
760 blk_complete_request(cmd->request);
764 * scsi_finish_command - cleanup and pass command back to upper layer
767 * Description: Pass command off to upper layer for finishing of I/O
768 * request, waking processes that are waiting on results,
771 void scsi_finish_command(struct scsi_cmnd *cmd)
773 struct scsi_device *sdev = cmd->device;
774 struct scsi_target *starget = scsi_target(sdev);
775 struct Scsi_Host *shost = sdev->host;
776 struct scsi_driver *drv;
777 unsigned int good_bytes;
779 scsi_device_unbusy(sdev);
782 * Clear the flags which say that the device/host is no longer
783 * capable of accepting new commands. These are set in scsi_queue.c
784 * for both the queue full condition on a device, and for a
785 * host full condition on the host.
787 * XXX(hch): What about locking?
789 shost->host_blocked = 0;
790 starget->target_blocked = 0;
791 sdev->device_blocked = 0;
794 * If we have valid sense information, then some kind of recovery
795 * must have taken place. Make a note of this.
797 if (SCSI_SENSE_VALID(cmd))
798 cmd->result |= (DRIVER_SENSE << 24);
800 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
801 "Notifying upper driver of completion "
802 "(result %x)\n", cmd->result));
804 good_bytes = scsi_bufflen(cmd);
805 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
806 int old_good_bytes = good_bytes;
807 drv = scsi_cmd_to_driver(cmd);
809 good_bytes = drv->done(cmd);
811 * USB may not give sense identifying bad sector and
812 * simply return a residue instead, so subtract off the
813 * residue if drv->done() error processing indicates no
814 * change to the completion length.
816 if (good_bytes == old_good_bytes)
817 good_bytes -= scsi_get_resid(cmd);
819 scsi_io_completion(cmd, good_bytes);
821 EXPORT_SYMBOL(scsi_finish_command);
824 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
825 * @sdev: SCSI Device in question
826 * @tagged: Do we use tagged queueing (non-0) or do we treat
827 * this device as an untagged device (0)
828 * @tags: Number of tags allowed if tagged queueing enabled,
829 * or number of commands the low level driver can
830 * queue up in non-tagged mode (as per cmd_per_lun).
834 * Lock Status: None held on entry
836 * Notes: Low level drivers may call this at any time and we will do
837 * the right thing depending on whether or not the device is
838 * currently active and whether or not it even has the
839 * command blocks built yet.
841 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
846 * refuse to set tagged depth to an unworkable size
851 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
854 * Check to see if the queue is managed by the block layer.
855 * If it is, and we fail to adjust the depth, exit.
857 * Do not resize the tag map if it is a host wide share bqt,
858 * because the size should be the hosts's can_queue. If there
859 * is more IO than the LLD's can_queue (so there are not enuogh
860 * tags) request_fn's host queue ready check will handle it.
862 if (!sdev->host->bqt) {
863 if (blk_queue_tagged(sdev->request_queue) &&
864 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
868 sdev->queue_depth = tags;
870 case MSG_ORDERED_TAG:
871 sdev->ordered_tags = 1;
872 sdev->simple_tags = 1;
875 sdev->ordered_tags = 0;
876 sdev->simple_tags = 1;
879 sdev_printk(KERN_WARNING, sdev,
880 "scsi_adjust_queue_depth, bad queue type, "
883 sdev->ordered_tags = sdev->simple_tags = 0;
884 sdev->queue_depth = tags;
888 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
890 EXPORT_SYMBOL(scsi_adjust_queue_depth);
893 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
894 * @sdev: SCSI Device in question
895 * @depth: Current number of outstanding SCSI commands on this device,
896 * not counting the one returned as QUEUE_FULL.
898 * Description: This function will track successive QUEUE_FULL events on a
899 * specific SCSI device to determine if and when there is a
900 * need to adjust the queue depth on the device.
902 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
903 * -1 - Drop back to untagged operation using host->cmd_per_lun
904 * as the untagged command depth
906 * Lock Status: None held on entry
908 * Notes: Low level drivers may call this at any time and we will do
909 * "The Right Thing." We are interrupt context safe.
911 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
915 * Don't let QUEUE_FULLs on the same
916 * jiffies count, they could all be from
919 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
922 sdev->last_queue_full_time = jiffies;
923 if (sdev->last_queue_full_depth != depth) {
924 sdev->last_queue_full_count = 1;
925 sdev->last_queue_full_depth = depth;
927 sdev->last_queue_full_count++;
930 if (sdev->last_queue_full_count <= 10)
932 if (sdev->last_queue_full_depth < 8) {
933 /* Drop back to untagged */
934 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
938 if (sdev->ordered_tags)
939 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
941 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
944 EXPORT_SYMBOL(scsi_track_queue_full);
947 * scsi_vpd_inquiry - Request a device provide us with a VPD page
948 * @sdev: The device to ask
949 * @buffer: Where to put the result
950 * @page: Which Vital Product Data to return
951 * @len: The length of the buffer
953 * This is an internal helper function. You probably want to use
954 * scsi_get_vpd_page instead.
956 * Returns 0 on success or a negative error number.
958 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
959 u8 page, unsigned len)
962 unsigned char cmd[16];
965 cmd[1] = 1; /* EVPD */
969 cmd[5] = 0; /* Control byte */
972 * I'm not convinced we need to try quite this hard to get VPD, but
973 * all the existing users tried this hard.
975 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
976 len, NULL, 30 * HZ, 3, NULL);
980 /* Sanity check that we got the page back that we asked for */
981 if (buffer[1] != page)
988 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
989 * @sdev: The device to ask
990 * @page: Which Vital Product Data to return
991 * @buf: where to store the VPD
992 * @buf_len: number of bytes in the VPD buffer area
994 * SCSI devices may optionally supply Vital Product Data. Each 'page'
995 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
996 * If the device supports this VPD page, this routine returns a pointer
997 * to a buffer containing the data from that page. The caller is
998 * responsible for calling kfree() on this pointer when it is no longer
999 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1001 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1006 if (sdev->skip_vpd_pages)
1009 /* Ask for all the pages supported by this device */
1010 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1014 /* If the user actually wanted this page, we can skip the rest */
1018 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1019 if (buf[i + 4] == page)
1022 if (i < buf[3] && i >= buf_len - 4)
1023 /* ran off the end of the buffer, give us benefit of doubt */
1025 /* The device claims it doesn't support the requested page */
1029 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1038 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1041 * scsi_report_opcode - Find out if a given command opcode is supported
1042 * @sdev: scsi device to query
1043 * @buffer: scratch buffer (must be at least 20 bytes long)
1044 * @len: length of buffer
1045 * @opcode: opcode for command to look up
1047 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1048 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1049 * unsupported and 1 if the device claims to support the command.
1051 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1052 unsigned int len, unsigned char opcode)
1054 unsigned char cmd[16];
1055 struct scsi_sense_hdr sshdr;
1058 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1062 cmd[0] = MAINTENANCE_IN;
1063 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1064 cmd[2] = 1; /* One command format */
1066 put_unaligned_be32(len, &cmd[6]);
1067 memset(buffer, 0, len);
1069 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1070 &sshdr, 30 * HZ, 3, NULL);
1072 if (result && scsi_sense_valid(&sshdr) &&
1073 sshdr.sense_key == ILLEGAL_REQUEST &&
1074 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1077 if ((buffer[1] & 3) == 3) /* Command supported */
1082 EXPORT_SYMBOL(scsi_report_opcode);
1085 * scsi_device_get - get an additional reference to a scsi_device
1086 * @sdev: device to get a reference to
1088 * Description: Gets a reference to the scsi_device and increments the use count
1089 * of the underlying LLDD module. You must hold host_lock of the
1090 * parent Scsi_Host or already have a reference when calling this.
1092 int scsi_device_get(struct scsi_device *sdev)
1094 if (sdev->sdev_state == SDEV_DEL)
1096 if (!get_device(&sdev->sdev_gendev))
1098 /* We can fail this if we're doing SCSI operations
1099 * from module exit (like cache flush) */
1100 try_module_get(sdev->host->hostt->module);
1104 EXPORT_SYMBOL(scsi_device_get);
1107 * scsi_device_put - release a reference to a scsi_device
1108 * @sdev: device to release a reference on.
1110 * Description: Release a reference to the scsi_device and decrements the use
1111 * count of the underlying LLDD module. The device is freed once the last
1114 void scsi_device_put(struct scsi_device *sdev)
1116 #ifdef CONFIG_MODULE_UNLOAD
1117 struct module *module = sdev->host->hostt->module;
1119 /* The module refcount will be zero if scsi_device_get()
1120 * was called from a module removal routine */
1121 if (module && module_refcount(module) != 0)
1124 put_device(&sdev->sdev_gendev);
1126 EXPORT_SYMBOL(scsi_device_put);
1128 /* helper for shost_for_each_device, see that for documentation */
1129 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1130 struct scsi_device *prev)
1132 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1133 struct scsi_device *next = NULL;
1134 unsigned long flags;
1136 spin_lock_irqsave(shost->host_lock, flags);
1137 while (list->next != &shost->__devices) {
1138 next = list_entry(list->next, struct scsi_device, siblings);
1139 /* skip devices that we can't get a reference to */
1140 if (!scsi_device_get(next))
1145 spin_unlock_irqrestore(shost->host_lock, flags);
1148 scsi_device_put(prev);
1151 EXPORT_SYMBOL(__scsi_iterate_devices);
1154 * starget_for_each_device - helper to walk all devices of a target
1155 * @starget: target whose devices we want to iterate over.
1156 * @data: Opaque passed to each function call.
1157 * @fn: Function to call on each device
1159 * This traverses over each device of @starget. The devices have
1160 * a reference that must be released by scsi_host_put when breaking
1163 void starget_for_each_device(struct scsi_target *starget, void *data,
1164 void (*fn)(struct scsi_device *, void *))
1166 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1167 struct scsi_device *sdev;
1169 shost_for_each_device(sdev, shost) {
1170 if ((sdev->channel == starget->channel) &&
1171 (sdev->id == starget->id))
1175 EXPORT_SYMBOL(starget_for_each_device);
1178 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1179 * @starget: target whose devices we want to iterate over.
1180 * @data: parameter for callback @fn()
1181 * @fn: callback function that is invoked for each device
1183 * This traverses over each device of @starget. It does _not_
1184 * take a reference on the scsi_device, so the whole loop must be
1185 * protected by shost->host_lock.
1187 * Note: The only reason why drivers would want to use this is because
1188 * they need to access the device list in irq context. Otherwise you
1189 * really want to use starget_for_each_device instead.
1191 void __starget_for_each_device(struct scsi_target *starget, void *data,
1192 void (*fn)(struct scsi_device *, void *))
1194 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1195 struct scsi_device *sdev;
1197 __shost_for_each_device(sdev, shost) {
1198 if ((sdev->channel == starget->channel) &&
1199 (sdev->id == starget->id))
1203 EXPORT_SYMBOL(__starget_for_each_device);
1206 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1207 * @starget: SCSI target pointer
1208 * @lun: SCSI Logical Unit Number
1210 * Description: Looks up the scsi_device with the specified @lun for a given
1211 * @starget. The returned scsi_device does not have an additional
1212 * reference. You must hold the host's host_lock over this call and
1213 * any access to the returned scsi_device. A scsi_device in state
1214 * SDEV_DEL is skipped.
1216 * Note: The only reason why drivers should use this is because
1217 * they need to access the device list in irq context. Otherwise you
1218 * really want to use scsi_device_lookup_by_target instead.
1220 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1223 struct scsi_device *sdev;
1225 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1226 if (sdev->sdev_state == SDEV_DEL)
1228 if (sdev->lun ==lun)
1234 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1237 * scsi_device_lookup_by_target - find a device given the target
1238 * @starget: SCSI target pointer
1239 * @lun: SCSI Logical Unit Number
1241 * Description: Looks up the scsi_device with the specified @lun for a given
1242 * @starget. The returned scsi_device has an additional reference that
1243 * needs to be released with scsi_device_put once you're done with it.
1245 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1248 struct scsi_device *sdev;
1249 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1250 unsigned long flags;
1252 spin_lock_irqsave(shost->host_lock, flags);
1253 sdev = __scsi_device_lookup_by_target(starget, lun);
1254 if (sdev && scsi_device_get(sdev))
1256 spin_unlock_irqrestore(shost->host_lock, flags);
1260 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1263 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1264 * @shost: SCSI host pointer
1265 * @channel: SCSI channel (zero if only one channel)
1266 * @id: SCSI target number (physical unit number)
1267 * @lun: SCSI Logical Unit Number
1269 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1270 * for a given host. The returned scsi_device does not have an additional
1271 * reference. You must hold the host's host_lock over this call and any access
1272 * to the returned scsi_device.
1274 * Note: The only reason why drivers would want to use this is because
1275 * they need to access the device list in irq context. Otherwise you
1276 * really want to use scsi_device_lookup instead.
1278 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1279 uint channel, uint id, uint lun)
1281 struct scsi_device *sdev;
1283 list_for_each_entry(sdev, &shost->__devices, siblings) {
1284 if (sdev->channel == channel && sdev->id == id &&
1291 EXPORT_SYMBOL(__scsi_device_lookup);
1294 * scsi_device_lookup - find a device given the host
1295 * @shost: SCSI host pointer
1296 * @channel: SCSI channel (zero if only one channel)
1297 * @id: SCSI target number (physical unit number)
1298 * @lun: SCSI Logical Unit Number
1300 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1301 * for a given host. The returned scsi_device has an additional reference that
1302 * needs to be released with scsi_device_put once you're done with it.
1304 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1305 uint channel, uint id, uint lun)
1307 struct scsi_device *sdev;
1308 unsigned long flags;
1310 spin_lock_irqsave(shost->host_lock, flags);
1311 sdev = __scsi_device_lookup(shost, channel, id, lun);
1312 if (sdev && scsi_device_get(sdev))
1314 spin_unlock_irqrestore(shost->host_lock, flags);
1318 EXPORT_SYMBOL(scsi_device_lookup);
1320 MODULE_DESCRIPTION("SCSI core");
1321 MODULE_LICENSE("GPL");
1323 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1324 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1326 static int __init init_scsi(void)
1330 error = scsi_init_queue();
1333 error = scsi_init_procfs();
1336 error = scsi_init_devinfo();
1338 goto cleanup_procfs;
1339 error = scsi_init_hosts();
1341 goto cleanup_devlist;
1342 error = scsi_init_sysctl();
1345 error = scsi_sysfs_register();
1347 goto cleanup_sysctl;
1349 scsi_netlink_init();
1351 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1359 scsi_exit_devinfo();
1364 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1369 static void __exit exit_scsi(void)
1371 scsi_netlink_exit();
1372 scsi_sysfs_unregister();
1375 scsi_exit_devinfo();
1378 async_unregister_domain(&scsi_sd_probe_domain);
1381 subsys_initcall(init_scsi);
1382 module_exit(exit_scsi);