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);
95 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
96 * asynchronous system resume operations. It is marked 'exclusive' to avoid
97 * being included in the async_synchronize_full() that is invoked by
100 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
101 EXPORT_SYMBOL(scsi_sd_pm_domain);
103 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
104 * You may not alter any existing entry (although adding new ones is
105 * encouraged once assigned by ANSI/INCITS T10
107 static const char *const scsi_device_types[] = {
130 * scsi_device_type - Return 17 char string indicating device type.
131 * @type: type number to look up
134 const char * scsi_device_type(unsigned type)
137 return "Well-known LUN ";
140 if (type >= ARRAY_SIZE(scsi_device_types))
142 return scsi_device_types[type];
145 EXPORT_SYMBOL(scsi_device_type);
147 struct scsi_host_cmd_pool {
148 struct kmem_cache *cmd_slab;
149 struct kmem_cache *sense_slab;
153 unsigned int slab_flags;
157 static struct scsi_host_cmd_pool scsi_cmd_pool = {
158 .cmd_name = "scsi_cmd_cache",
159 .sense_name = "scsi_sense_cache",
160 .slab_flags = SLAB_HWCACHE_ALIGN,
163 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
164 .cmd_name = "scsi_cmd_cache(DMA)",
165 .sense_name = "scsi_sense_cache(DMA)",
166 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
167 .gfp_mask = __GFP_DMA,
170 static DEFINE_MUTEX(host_cmd_pool_mutex);
173 * scsi_pool_alloc_command - internal function to get a fully allocated command
174 * @pool: slab pool to allocate the command from
175 * @gfp_mask: mask for the allocation
177 * Returns a fully allocated command (with the allied sense buffer) or
180 static struct scsi_cmnd *
181 scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
183 struct scsi_cmnd *cmd;
185 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
189 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
190 gfp_mask | pool->gfp_mask);
191 if (!cmd->sense_buffer) {
192 kmem_cache_free(pool->cmd_slab, cmd);
200 * scsi_pool_free_command - internal function to release a command
201 * @pool: slab pool to allocate the command from
202 * @cmd: command to release
204 * the command must previously have been allocated by
205 * scsi_pool_alloc_command.
208 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
209 struct scsi_cmnd *cmd)
212 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
214 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
215 kmem_cache_free(pool->cmd_slab, cmd);
219 * scsi_host_alloc_command - internal function to allocate command
220 * @shost: SCSI host whose pool to allocate from
221 * @gfp_mask: mask for the allocation
223 * Returns a fully allocated command with sense buffer and protection
224 * data buffer (where applicable) or NULL on failure
226 static struct scsi_cmnd *
227 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
229 struct scsi_cmnd *cmd;
231 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
235 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
236 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
238 if (!cmd->prot_sdb) {
239 scsi_pool_free_command(shost->cmd_pool, cmd);
248 * __scsi_get_command - Allocate a struct scsi_cmnd
249 * @shost: host to transmit command
250 * @gfp_mask: allocation mask
252 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
253 * host's free_list if necessary.
255 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
257 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
259 if (unlikely(!cmd)) {
262 spin_lock_irqsave(&shost->free_list_lock, flags);
263 if (likely(!list_empty(&shost->free_list))) {
264 cmd = list_entry(shost->free_list.next,
265 struct scsi_cmnd, list);
266 list_del_init(&cmd->list);
268 spin_unlock_irqrestore(&shost->free_list_lock, flags);
273 buf = cmd->sense_buffer;
274 prot = cmd->prot_sdb;
276 memset(cmd, 0, sizeof(*cmd));
278 cmd->sense_buffer = buf;
279 cmd->prot_sdb = prot;
285 EXPORT_SYMBOL_GPL(__scsi_get_command);
288 * scsi_get_command - Allocate and setup a scsi command block
289 * @dev: parent scsi device
290 * @gfp_mask: allocator flags
292 * Returns: The allocated scsi command structure.
294 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
296 struct scsi_cmnd *cmd;
298 /* Bail if we can't get a reference to the device */
299 if (!get_device(&dev->sdev_gendev))
302 cmd = __scsi_get_command(dev->host, gfp_mask);
304 if (likely(cmd != NULL)) {
308 INIT_LIST_HEAD(&cmd->list);
309 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
310 spin_lock_irqsave(&dev->list_lock, flags);
311 list_add_tail(&cmd->list, &dev->cmd_list);
312 spin_unlock_irqrestore(&dev->list_lock, flags);
313 cmd->jiffies_at_alloc = jiffies;
315 put_device(&dev->sdev_gendev);
319 EXPORT_SYMBOL(scsi_get_command);
322 * __scsi_put_command - Free a struct scsi_cmnd
324 * @cmd: Command to free
325 * @dev: parent scsi device
327 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
332 /* changing locks here, don't need to restore the irq state */
333 spin_lock_irqsave(&shost->free_list_lock, flags);
334 if (unlikely(list_empty(&shost->free_list))) {
335 list_add(&cmd->list, &shost->free_list);
338 spin_unlock_irqrestore(&shost->free_list_lock, flags);
340 if (likely(cmd != NULL))
341 scsi_pool_free_command(shost->cmd_pool, cmd);
345 EXPORT_SYMBOL(__scsi_put_command);
348 * scsi_put_command - Free a scsi command block
349 * @cmd: command block to free
353 * Notes: The command must not belong to any lists.
355 void scsi_put_command(struct scsi_cmnd *cmd)
357 struct scsi_device *sdev = cmd->device;
360 /* serious error if the command hasn't come from a device list */
361 spin_lock_irqsave(&cmd->device->list_lock, flags);
362 BUG_ON(list_empty(&cmd->list));
363 list_del_init(&cmd->list);
364 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
366 cancel_delayed_work(&cmd->abort_work);
368 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
370 EXPORT_SYMBOL(scsi_put_command);
372 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
374 struct scsi_host_cmd_pool *retval = NULL, *pool;
376 * Select a command slab for this host and create it if not
379 mutex_lock(&host_cmd_pool_mutex);
380 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
383 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
384 sizeof(struct scsi_cmnd), 0,
385 pool->slab_flags, NULL);
389 pool->sense_slab = kmem_cache_create(pool->sense_name,
390 SCSI_SENSE_BUFFERSIZE, 0,
391 pool->slab_flags, NULL);
392 if (!pool->sense_slab) {
393 kmem_cache_destroy(pool->cmd_slab);
401 mutex_unlock(&host_cmd_pool_mutex);
405 static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
407 struct scsi_host_cmd_pool *pool;
409 mutex_lock(&host_cmd_pool_mutex);
410 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
413 * This may happen if a driver has a mismatched get and put
414 * of the command pool; the driver should be implicated in
417 BUG_ON(pool->users == 0);
419 if (!--pool->users) {
420 kmem_cache_destroy(pool->cmd_slab);
421 kmem_cache_destroy(pool->sense_slab);
423 mutex_unlock(&host_cmd_pool_mutex);
427 * scsi_allocate_command - get a fully allocated SCSI command
428 * @gfp_mask: allocation mask
430 * This function is for use outside of the normal host based pools.
431 * It allocates the relevant command and takes an additional reference
432 * on the pool it used. This function *must* be paired with
433 * scsi_free_command which also has the identical mask, otherwise the
434 * free pool counts will eventually go wrong and you'll trigger a bug.
436 * This function should *only* be used by drivers that need a static
437 * command allocation at start of day for internal functions.
439 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
441 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
446 return scsi_pool_alloc_command(pool, gfp_mask);
448 EXPORT_SYMBOL(scsi_allocate_command);
451 * scsi_free_command - free a command allocated by scsi_allocate_command
452 * @gfp_mask: mask used in the original allocation
453 * @cmd: command to free
455 * Note: using the original allocation mask is vital because that's
456 * what determines which command pool we use to free the command. Any
457 * mismatch will cause the system to BUG eventually.
459 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
461 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
464 * this could trigger if the mask to scsi_allocate_command
465 * doesn't match this mask. Otherwise we're guaranteed that this
466 * succeeds because scsi_allocate_command must have taken a reference
471 scsi_pool_free_command(pool, cmd);
473 * scsi_put_host_cmd_pool is called twice; once to release the
474 * reference we took above, and once to release the reference
475 * originally taken by scsi_allocate_command
477 scsi_put_host_cmd_pool(gfp_mask);
478 scsi_put_host_cmd_pool(gfp_mask);
480 EXPORT_SYMBOL(scsi_free_command);
483 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
484 * @shost: host to allocate the freelist for.
486 * Description: The command freelist protects against system-wide out of memory
487 * deadlock by preallocating one SCSI command structure for each host, so the
488 * system can always write to a swap file on a device associated with that host.
492 int scsi_setup_command_freelist(struct Scsi_Host *shost)
494 struct scsi_cmnd *cmd;
495 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
497 spin_lock_init(&shost->free_list_lock);
498 INIT_LIST_HEAD(&shost->free_list);
500 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
502 if (!shost->cmd_pool)
506 * Get one backup command for this host.
508 cmd = scsi_host_alloc_command(shost, gfp_mask);
510 scsi_put_host_cmd_pool(gfp_mask);
511 shost->cmd_pool = NULL;
514 list_add(&cmd->list, &shost->free_list);
519 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
520 * @shost: host whose freelist is going to be destroyed
522 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
525 * If cmd_pool is NULL the free list was not initialized, so
526 * do not attempt to release resources.
528 if (!shost->cmd_pool)
531 while (!list_empty(&shost->free_list)) {
532 struct scsi_cmnd *cmd;
534 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
535 list_del_init(&cmd->list);
536 scsi_pool_free_command(shost->cmd_pool, cmd);
538 shost->cmd_pool = NULL;
539 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
542 #ifdef CONFIG_SCSI_LOGGING
543 void scsi_log_send(struct scsi_cmnd *cmd)
548 * If ML QUEUE log level is greater than or equal to:
550 * 1: nothing (match completion)
552 * 2: log opcode + command of all commands
554 * 3: same as 2 plus dump cmd address
556 * 4: same as 3 plus dump extra junk
558 if (unlikely(scsi_logging_level)) {
559 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
560 SCSI_LOG_MLQUEUE_BITS);
562 scmd_printk(KERN_INFO, cmd, "Send: ");
564 printk("0x%p ", cmd);
566 scsi_print_command(cmd);
568 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
569 " queuecommand 0x%p\n",
570 scsi_sglist(cmd), scsi_bufflen(cmd),
571 cmd->device->host->hostt->queuecommand);
578 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
583 * If ML COMPLETE log level is greater than or equal to:
585 * 1: log disposition, result, opcode + command, and conditionally
586 * sense data for failures or non SUCCESS dispositions.
588 * 2: same as 1 but for all command completions.
590 * 3: same as 2 plus dump cmd address
592 * 4: same as 3 plus dump extra junk
594 if (unlikely(scsi_logging_level)) {
595 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
596 SCSI_LOG_MLCOMPLETE_BITS);
597 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
599 scmd_printk(KERN_INFO, cmd, "Done: ");
601 printk("0x%p ", cmd);
603 * Dump truncated values, so we usually fit within
606 switch (disposition) {
621 * If called via scsi_times_out.
628 scsi_print_result(cmd);
629 scsi_print_command(cmd);
630 if (status_byte(cmd->result) & CHECK_CONDITION)
631 scsi_print_sense("", cmd);
633 scmd_printk(KERN_INFO, cmd,
634 "scsi host busy %d failed %d\n",
635 cmd->device->host->host_busy,
636 cmd->device->host->host_failed);
643 * scsi_cmd_get_serial - Assign a serial number to a command
644 * @host: the scsi host
645 * @cmd: command to assign serial number to
647 * Description: a serial number identifies a request for error recovery
648 * and debugging purposes. Protected by the Host_Lock of host.
650 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
652 cmd->serial_number = host->cmd_serial_number++;
653 if (cmd->serial_number == 0)
654 cmd->serial_number = host->cmd_serial_number++;
656 EXPORT_SYMBOL(scsi_cmd_get_serial);
659 * scsi_dispatch_command - Dispatch a command to the low-level driver.
660 * @cmd: command block we are dispatching.
662 * Return: nonzero return request was rejected and device's queue needs to be
665 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
667 struct Scsi_Host *host = cmd->device->host;
670 atomic_inc(&cmd->device->iorequest_cnt);
672 /* check if the device is still usable */
673 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
674 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
675 * returns an immediate error upwards, and signals
676 * that the device is no longer present */
677 cmd->result = DID_NO_CONNECT << 16;
679 /* return 0 (because the command has been processed) */
683 /* Check to see if the scsi lld made this device blocked. */
684 if (unlikely(scsi_device_blocked(cmd->device))) {
686 * in blocked state, the command is just put back on
687 * the device queue. The suspend state has already
688 * blocked the queue so future requests should not
689 * occur until the device transitions out of the
693 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
695 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
698 * NOTE: rtn is still zero here because we don't need the
699 * queue to be plugged on return (it's already stopped)
705 * If SCSI-2 or lower, store the LUN value in cmnd.
707 if (cmd->device->scsi_level <= SCSI_2 &&
708 cmd->device->scsi_level != SCSI_UNKNOWN) {
709 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
710 (cmd->device->lun << 5 & 0xe0);
716 * Before we queue this command, check if the command
717 * length exceeds what the host adapter can handle.
719 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
721 printk("queuecommand : command too long. "
722 "cdb_size=%d host->max_cmd_len=%d\n",
723 cmd->cmd_len, cmd->device->host->max_cmd_len));
724 cmd->result = (DID_ABORT << 16);
730 if (unlikely(host->shost_state == SHOST_DEL)) {
731 cmd->result = (DID_NO_CONNECT << 16);
734 trace_scsi_dispatch_cmd_start(cmd);
735 cmd->scsi_done = scsi_done;
736 rtn = host->hostt->queuecommand(host, cmd);
740 trace_scsi_dispatch_cmd_error(cmd, rtn);
741 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
742 rtn != SCSI_MLQUEUE_TARGET_BUSY)
743 rtn = SCSI_MLQUEUE_HOST_BUSY;
745 scsi_queue_insert(cmd, rtn);
748 printk("queuecommand : request rejected\n"));
752 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
757 * scsi_done - Invoke completion on finished SCSI command.
758 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
759 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
761 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
762 * which regains ownership of the SCSI command (de facto) from a LLDD, and
763 * calls blk_complete_request() for further processing.
765 * This function is interrupt context safe.
767 static void scsi_done(struct scsi_cmnd *cmd)
769 trace_scsi_dispatch_cmd_done(cmd);
770 blk_complete_request(cmd->request);
774 * scsi_finish_command - cleanup and pass command back to upper layer
777 * Description: Pass command off to upper layer for finishing of I/O
778 * request, waking processes that are waiting on results,
781 void scsi_finish_command(struct scsi_cmnd *cmd)
783 struct scsi_device *sdev = cmd->device;
784 struct scsi_target *starget = scsi_target(sdev);
785 struct Scsi_Host *shost = sdev->host;
786 struct scsi_driver *drv;
787 unsigned int good_bytes;
789 scsi_device_unbusy(sdev);
792 * Clear the flags which say that the device/host is no longer
793 * capable of accepting new commands. These are set in scsi_queue.c
794 * for both the queue full condition on a device, and for a
795 * host full condition on the host.
797 * XXX(hch): What about locking?
799 shost->host_blocked = 0;
800 starget->target_blocked = 0;
801 sdev->device_blocked = 0;
804 * If we have valid sense information, then some kind of recovery
805 * must have taken place. Make a note of this.
807 if (SCSI_SENSE_VALID(cmd))
808 cmd->result |= (DRIVER_SENSE << 24);
810 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
811 "Notifying upper driver of completion "
812 "(result %x)\n", cmd->result));
814 good_bytes = scsi_bufflen(cmd);
815 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
816 int old_good_bytes = good_bytes;
817 drv = scsi_cmd_to_driver(cmd);
819 good_bytes = drv->done(cmd);
821 * USB may not give sense identifying bad sector and
822 * simply return a residue instead, so subtract off the
823 * residue if drv->done() error processing indicates no
824 * change to the completion length.
826 if (good_bytes == old_good_bytes)
827 good_bytes -= scsi_get_resid(cmd);
829 scsi_io_completion(cmd, good_bytes);
831 EXPORT_SYMBOL(scsi_finish_command);
834 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
835 * @sdev: SCSI Device in question
836 * @tagged: Do we use tagged queueing (non-0) or do we treat
837 * this device as an untagged device (0)
838 * @tags: Number of tags allowed if tagged queueing enabled,
839 * or number of commands the low level driver can
840 * queue up in non-tagged mode (as per cmd_per_lun).
844 * Lock Status: None held on entry
846 * Notes: Low level drivers may call this at any time and we will do
847 * the right thing depending on whether or not the device is
848 * currently active and whether or not it even has the
849 * command blocks built yet.
851 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
856 * refuse to set tagged depth to an unworkable size
861 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
864 * Check to see if the queue is managed by the block layer.
865 * If it is, and we fail to adjust the depth, exit.
867 * Do not resize the tag map if it is a host wide share bqt,
868 * because the size should be the hosts's can_queue. If there
869 * is more IO than the LLD's can_queue (so there are not enuogh
870 * tags) request_fn's host queue ready check will handle it.
872 if (!sdev->host->bqt) {
873 if (blk_queue_tagged(sdev->request_queue) &&
874 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
878 sdev->queue_depth = tags;
880 case MSG_ORDERED_TAG:
881 sdev->ordered_tags = 1;
882 sdev->simple_tags = 1;
885 sdev->ordered_tags = 0;
886 sdev->simple_tags = 1;
889 sdev_printk(KERN_WARNING, sdev,
890 "scsi_adjust_queue_depth, bad queue type, "
893 sdev->ordered_tags = sdev->simple_tags = 0;
894 sdev->queue_depth = tags;
898 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
900 EXPORT_SYMBOL(scsi_adjust_queue_depth);
903 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
904 * @sdev: SCSI Device in question
905 * @depth: Current number of outstanding SCSI commands on this device,
906 * not counting the one returned as QUEUE_FULL.
908 * Description: This function will track successive QUEUE_FULL events on a
909 * specific SCSI device to determine if and when there is a
910 * need to adjust the queue depth on the device.
912 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
913 * -1 - Drop back to untagged operation using host->cmd_per_lun
914 * as the untagged command depth
916 * Lock Status: None held on entry
918 * Notes: Low level drivers may call this at any time and we will do
919 * "The Right Thing." We are interrupt context safe.
921 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
925 * Don't let QUEUE_FULLs on the same
926 * jiffies count, they could all be from
929 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
932 sdev->last_queue_full_time = jiffies;
933 if (sdev->last_queue_full_depth != depth) {
934 sdev->last_queue_full_count = 1;
935 sdev->last_queue_full_depth = depth;
937 sdev->last_queue_full_count++;
940 if (sdev->last_queue_full_count <= 10)
942 if (sdev->last_queue_full_depth < 8) {
943 /* Drop back to untagged */
944 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
948 if (sdev->ordered_tags)
949 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
951 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
954 EXPORT_SYMBOL(scsi_track_queue_full);
957 * scsi_vpd_inquiry - Request a device provide us with a VPD page
958 * @sdev: The device to ask
959 * @buffer: Where to put the result
960 * @page: Which Vital Product Data to return
961 * @len: The length of the buffer
963 * This is an internal helper function. You probably want to use
964 * scsi_get_vpd_page instead.
966 * Returns 0 on success or a negative error number.
968 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
969 u8 page, unsigned len)
972 unsigned char cmd[16];
975 cmd[1] = 1; /* EVPD */
979 cmd[5] = 0; /* Control byte */
982 * I'm not convinced we need to try quite this hard to get VPD, but
983 * all the existing users tried this hard.
985 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
986 len, NULL, 30 * HZ, 3, NULL);
990 /* Sanity check that we got the page back that we asked for */
991 if (buffer[1] != page)
998 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
999 * @sdev: The device to ask
1000 * @page: Which Vital Product Data to return
1001 * @buf: where to store the VPD
1002 * @buf_len: number of bytes in the VPD buffer area
1004 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1005 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1006 * If the device supports this VPD page, this routine returns a pointer
1007 * to a buffer containing the data from that page. The caller is
1008 * responsible for calling kfree() on this pointer when it is no longer
1009 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1011 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1016 if (sdev->skip_vpd_pages)
1019 /* Ask for all the pages supported by this device */
1020 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1024 /* If the user actually wanted this page, we can skip the rest */
1028 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1029 if (buf[i + 4] == page)
1032 if (i < buf[3] && i >= buf_len - 4)
1033 /* ran off the end of the buffer, give us benefit of doubt */
1035 /* The device claims it doesn't support the requested page */
1039 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1048 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1051 * scsi_report_opcode - Find out if a given command opcode is supported
1052 * @sdev: scsi device to query
1053 * @buffer: scratch buffer (must be at least 20 bytes long)
1054 * @len: length of buffer
1055 * @opcode: opcode for command to look up
1057 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1058 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1059 * unsupported and 1 if the device claims to support the command.
1061 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1062 unsigned int len, unsigned char opcode)
1064 unsigned char cmd[16];
1065 struct scsi_sense_hdr sshdr;
1068 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1072 cmd[0] = MAINTENANCE_IN;
1073 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1074 cmd[2] = 1; /* One command format */
1076 put_unaligned_be32(len, &cmd[6]);
1077 memset(buffer, 0, len);
1079 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1080 &sshdr, 30 * HZ, 3, NULL);
1082 if (result && scsi_sense_valid(&sshdr) &&
1083 sshdr.sense_key == ILLEGAL_REQUEST &&
1084 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1087 if ((buffer[1] & 3) == 3) /* Command supported */
1092 EXPORT_SYMBOL(scsi_report_opcode);
1095 * scsi_device_get - get an additional reference to a scsi_device
1096 * @sdev: device to get a reference to
1098 * Description: Gets a reference to the scsi_device and increments the use count
1099 * of the underlying LLDD module. You must hold host_lock of the
1100 * parent Scsi_Host or already have a reference when calling this.
1102 int scsi_device_get(struct scsi_device *sdev)
1104 if (sdev->sdev_state == SDEV_DEL)
1106 if (!get_device(&sdev->sdev_gendev))
1108 /* We can fail this if we're doing SCSI operations
1109 * from module exit (like cache flush) */
1110 try_module_get(sdev->host->hostt->module);
1114 EXPORT_SYMBOL(scsi_device_get);
1117 * scsi_device_put - release a reference to a scsi_device
1118 * @sdev: device to release a reference on.
1120 * Description: Release a reference to the scsi_device and decrements the use
1121 * count of the underlying LLDD module. The device is freed once the last
1124 void scsi_device_put(struct scsi_device *sdev)
1126 #ifdef CONFIG_MODULE_UNLOAD
1127 struct module *module = sdev->host->hostt->module;
1129 /* The module refcount will be zero if scsi_device_get()
1130 * was called from a module removal routine */
1131 if (module && module_refcount(module) != 0)
1134 put_device(&sdev->sdev_gendev);
1136 EXPORT_SYMBOL(scsi_device_put);
1138 /* helper for shost_for_each_device, see that for documentation */
1139 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1140 struct scsi_device *prev)
1142 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1143 struct scsi_device *next = NULL;
1144 unsigned long flags;
1146 spin_lock_irqsave(shost->host_lock, flags);
1147 while (list->next != &shost->__devices) {
1148 next = list_entry(list->next, struct scsi_device, siblings);
1149 /* skip devices that we can't get a reference to */
1150 if (!scsi_device_get(next))
1155 spin_unlock_irqrestore(shost->host_lock, flags);
1158 scsi_device_put(prev);
1161 EXPORT_SYMBOL(__scsi_iterate_devices);
1164 * starget_for_each_device - helper to walk all devices of a target
1165 * @starget: target whose devices we want to iterate over.
1166 * @data: Opaque passed to each function call.
1167 * @fn: Function to call on each device
1169 * This traverses over each device of @starget. The devices have
1170 * a reference that must be released by scsi_host_put when breaking
1173 void starget_for_each_device(struct scsi_target *starget, void *data,
1174 void (*fn)(struct scsi_device *, void *))
1176 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1177 struct scsi_device *sdev;
1179 shost_for_each_device(sdev, shost) {
1180 if ((sdev->channel == starget->channel) &&
1181 (sdev->id == starget->id))
1185 EXPORT_SYMBOL(starget_for_each_device);
1188 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1189 * @starget: target whose devices we want to iterate over.
1190 * @data: parameter for callback @fn()
1191 * @fn: callback function that is invoked for each device
1193 * This traverses over each device of @starget. It does _not_
1194 * take a reference on the scsi_device, so the whole loop must be
1195 * protected by shost->host_lock.
1197 * Note: The only reason why drivers would want to use this is because
1198 * they need to access the device list in irq context. Otherwise you
1199 * really want to use starget_for_each_device instead.
1201 void __starget_for_each_device(struct scsi_target *starget, void *data,
1202 void (*fn)(struct scsi_device *, void *))
1204 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1205 struct scsi_device *sdev;
1207 __shost_for_each_device(sdev, shost) {
1208 if ((sdev->channel == starget->channel) &&
1209 (sdev->id == starget->id))
1213 EXPORT_SYMBOL(__starget_for_each_device);
1216 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1217 * @starget: SCSI target pointer
1218 * @lun: SCSI Logical Unit Number
1220 * Description: Looks up the scsi_device with the specified @lun for a given
1221 * @starget. The returned scsi_device does not have an additional
1222 * reference. You must hold the host's host_lock over this call and
1223 * any access to the returned scsi_device. A scsi_device in state
1224 * SDEV_DEL is skipped.
1226 * Note: The only reason why drivers should use this is because
1227 * they need to access the device list in irq context. Otherwise you
1228 * really want to use scsi_device_lookup_by_target instead.
1230 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1233 struct scsi_device *sdev;
1235 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1236 if (sdev->sdev_state == SDEV_DEL)
1238 if (sdev->lun ==lun)
1244 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1247 * scsi_device_lookup_by_target - find a device given the target
1248 * @starget: SCSI target pointer
1249 * @lun: SCSI Logical Unit Number
1251 * Description: Looks up the scsi_device with the specified @lun for a given
1252 * @starget. The returned scsi_device has an additional reference that
1253 * needs to be released with scsi_device_put once you're done with it.
1255 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1258 struct scsi_device *sdev;
1259 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1260 unsigned long flags;
1262 spin_lock_irqsave(shost->host_lock, flags);
1263 sdev = __scsi_device_lookup_by_target(starget, lun);
1264 if (sdev && scsi_device_get(sdev))
1266 spin_unlock_irqrestore(shost->host_lock, flags);
1270 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1273 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1274 * @shost: SCSI host pointer
1275 * @channel: SCSI channel (zero if only one channel)
1276 * @id: SCSI target number (physical unit number)
1277 * @lun: SCSI Logical Unit Number
1279 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1280 * for a given host. The returned scsi_device does not have an additional
1281 * reference. You must hold the host's host_lock over this call and any access
1282 * to the returned scsi_device.
1284 * Note: The only reason why drivers would want to use this is because
1285 * they need to access the device list in irq context. Otherwise you
1286 * really want to use scsi_device_lookup instead.
1288 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1289 uint channel, uint id, uint lun)
1291 struct scsi_device *sdev;
1293 list_for_each_entry(sdev, &shost->__devices, siblings) {
1294 if (sdev->channel == channel && sdev->id == id &&
1301 EXPORT_SYMBOL(__scsi_device_lookup);
1304 * scsi_device_lookup - find a device given the host
1305 * @shost: SCSI host pointer
1306 * @channel: SCSI channel (zero if only one channel)
1307 * @id: SCSI target number (physical unit number)
1308 * @lun: SCSI Logical Unit Number
1310 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1311 * for a given host. The returned scsi_device has an additional reference that
1312 * needs to be released with scsi_device_put once you're done with it.
1314 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1315 uint channel, uint id, uint lun)
1317 struct scsi_device *sdev;
1318 unsigned long flags;
1320 spin_lock_irqsave(shost->host_lock, flags);
1321 sdev = __scsi_device_lookup(shost, channel, id, lun);
1322 if (sdev && scsi_device_get(sdev))
1324 spin_unlock_irqrestore(shost->host_lock, flags);
1328 EXPORT_SYMBOL(scsi_device_lookup);
1330 MODULE_DESCRIPTION("SCSI core");
1331 MODULE_LICENSE("GPL");
1333 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1334 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1336 static int __init init_scsi(void)
1340 error = scsi_init_queue();
1343 error = scsi_init_procfs();
1346 error = scsi_init_devinfo();
1348 goto cleanup_procfs;
1349 error = scsi_init_hosts();
1351 goto cleanup_devlist;
1352 error = scsi_init_sysctl();
1355 error = scsi_sysfs_register();
1357 goto cleanup_sysctl;
1359 scsi_netlink_init();
1361 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1369 scsi_exit_devinfo();
1374 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1379 static void __exit exit_scsi(void)
1381 scsi_netlink_exit();
1382 scsi_sysfs_unregister();
1385 scsi_exit_devinfo();
1388 async_unregister_domain(&scsi_sd_probe_domain);
1391 subsys_initcall(init_scsi);
1392 module_exit(exit_scsi);