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/sched.h>
44 #include <linux/timer.h>
45 #include <linux/string.h>
46 #include <linux/slab.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/init.h>
50 #include <linux/completion.h>
51 #include <linux/unistd.h>
52 #include <linux/spinlock.h>
53 #include <linux/kmod.h>
54 #include <linux/interrupt.h>
55 #include <linux/notifier.h>
56 #include <linux/cpu.h>
57 #include <linux/mutex.h>
59 #include <scsi/scsi.h>
60 #include <scsi/scsi_cmnd.h>
61 #include <scsi/scsi_dbg.h>
62 #include <scsi/scsi_device.h>
63 #include <scsi/scsi_eh.h>
64 #include <scsi/scsi_host.h>
65 #include <scsi/scsi_tcq.h>
67 #include "scsi_priv.h"
68 #include "scsi_logging.h"
70 static void scsi_done(struct scsi_cmnd *cmd);
73 * Definitions and constants.
76 #define MIN_RESET_DELAY (2*HZ)
78 /* Do not call reset on error if we just did a reset within 15 sec. */
79 #define MIN_RESET_PERIOD (15*HZ)
82 * Macro to determine the size of SCSI command. This macro takes vendor
83 * unique commands into account. SCSI commands in groups 6 and 7 are
84 * vendor unique and we will depend upon the command length being
85 * supplied correctly in cmd_len.
87 #define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
88 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
91 * Note - the initial logging level can be set here to log events at boot time.
92 * After the system is up, you may enable logging via the /proc interface.
94 unsigned int scsi_logging_level;
95 #if defined(CONFIG_SCSI_LOGGING)
96 EXPORT_SYMBOL(scsi_logging_level);
99 static const char *const scsi_device_types[] = {
121 const char * scsi_device_type(unsigned type)
124 return "Well-known LUN ";
127 if (type > ARRAY_SIZE(scsi_device_types))
129 return scsi_device_types[type];
132 EXPORT_SYMBOL(scsi_device_type);
134 struct scsi_host_cmd_pool {
138 unsigned int slab_flags;
142 static struct scsi_host_cmd_pool scsi_cmd_pool = {
143 .name = "scsi_cmd_cache",
144 .slab_flags = SLAB_HWCACHE_ALIGN,
147 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
148 .name = "scsi_cmd_cache(DMA)",
149 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
150 .gfp_mask = __GFP_DMA,
153 static DEFINE_MUTEX(host_cmd_pool_mutex);
155 static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost,
158 struct scsi_cmnd *cmd;
160 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
161 gfp_mask | shost->cmd_pool->gfp_mask);
163 if (unlikely(!cmd)) {
166 spin_lock_irqsave(&shost->free_list_lock, flags);
167 if (likely(!list_empty(&shost->free_list))) {
168 cmd = list_entry(shost->free_list.next,
169 struct scsi_cmnd, list);
170 list_del_init(&cmd->list);
172 spin_unlock_irqrestore(&shost->free_list_lock, flags);
179 * Function: scsi_get_command()
181 * Purpose: Allocate and setup a scsi command block
183 * Arguments: dev - parent scsi device
184 * gfp_mask- allocator flags
186 * Returns: The allocated scsi command structure.
188 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
190 struct scsi_cmnd *cmd;
192 /* Bail if we can't get a reference to the device */
193 if (!get_device(&dev->sdev_gendev))
196 cmd = __scsi_get_command(dev->host, gfp_mask);
198 if (likely(cmd != NULL)) {
201 memset(cmd, 0, sizeof(*cmd));
203 init_timer(&cmd->eh_timeout);
204 INIT_LIST_HEAD(&cmd->list);
205 spin_lock_irqsave(&dev->list_lock, flags);
206 list_add_tail(&cmd->list, &dev->cmd_list);
207 spin_unlock_irqrestore(&dev->list_lock, flags);
208 cmd->jiffies_at_alloc = jiffies;
210 put_device(&dev->sdev_gendev);
214 EXPORT_SYMBOL(scsi_get_command);
217 * Function: scsi_put_command()
219 * Purpose: Free a scsi command block
221 * Arguments: cmd - command block to free
225 * Notes: The command must not belong to any lists.
227 void scsi_put_command(struct scsi_cmnd *cmd)
229 struct scsi_device *sdev = cmd->device;
230 struct Scsi_Host *shost = sdev->host;
233 /* serious error if the command hasn't come from a device list */
234 spin_lock_irqsave(&cmd->device->list_lock, flags);
235 BUG_ON(list_empty(&cmd->list));
236 list_del_init(&cmd->list);
237 spin_unlock(&cmd->device->list_lock);
238 /* changing locks here, don't need to restore the irq state */
239 spin_lock(&shost->free_list_lock);
240 if (unlikely(list_empty(&shost->free_list))) {
241 list_add(&cmd->list, &shost->free_list);
244 spin_unlock_irqrestore(&shost->free_list_lock, flags);
246 if (likely(cmd != NULL))
247 kmem_cache_free(shost->cmd_pool->slab, cmd);
249 put_device(&sdev->sdev_gendev);
251 EXPORT_SYMBOL(scsi_put_command);
254 * Function: scsi_setup_command_freelist()
256 * Purpose: Setup the command freelist for a scsi host.
258 * Arguments: shost - host to allocate the freelist for.
262 int scsi_setup_command_freelist(struct Scsi_Host *shost)
264 struct scsi_host_cmd_pool *pool;
265 struct scsi_cmnd *cmd;
267 spin_lock_init(&shost->free_list_lock);
268 INIT_LIST_HEAD(&shost->free_list);
271 * Select a command slab for this host and create it if not
274 mutex_lock(&host_cmd_pool_mutex);
275 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
277 pool->slab = kmem_cache_create(pool->name,
278 sizeof(struct scsi_cmnd), 0,
279 pool->slab_flags, NULL, NULL);
285 shost->cmd_pool = pool;
286 mutex_unlock(&host_cmd_pool_mutex);
289 * Get one backup command for this host.
291 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
292 GFP_KERNEL | shost->cmd_pool->gfp_mask);
295 list_add(&cmd->list, &shost->free_list);
300 kmem_cache_destroy(pool->slab);
303 mutex_unlock(&host_cmd_pool_mutex);
309 * Function: scsi_destroy_command_freelist()
311 * Purpose: Release the command freelist for a scsi host.
313 * Arguments: shost - host that's freelist is going to be destroyed
315 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
317 while (!list_empty(&shost->free_list)) {
318 struct scsi_cmnd *cmd;
320 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
321 list_del_init(&cmd->list);
322 kmem_cache_free(shost->cmd_pool->slab, cmd);
325 mutex_lock(&host_cmd_pool_mutex);
326 if (!--shost->cmd_pool->users)
327 kmem_cache_destroy(shost->cmd_pool->slab);
328 mutex_unlock(&host_cmd_pool_mutex);
331 #ifdef CONFIG_SCSI_LOGGING
332 void scsi_log_send(struct scsi_cmnd *cmd)
335 struct scsi_device *sdev;
338 * If ML QUEUE log level is greater than or equal to:
340 * 1: nothing (match completion)
342 * 2: log opcode + command of all commands
344 * 3: same as 2 plus dump cmd address
346 * 4: same as 3 plus dump extra junk
348 if (unlikely(scsi_logging_level)) {
349 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
350 SCSI_LOG_MLQUEUE_BITS);
353 sdev_printk(KERN_INFO, sdev, "send ");
355 printk("0x%p ", cmd);
357 * spaces to match disposition and cmd->result
358 * output in scsi_log_completion.
361 scsi_print_command(cmd);
363 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
364 " done = 0x%p, queuecommand 0x%p\n",
365 cmd->request_buffer, cmd->request_bufflen,
367 sdev->host->hostt->queuecommand);
374 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
377 struct scsi_device *sdev;
380 * If ML COMPLETE log level is greater than or equal to:
382 * 1: log disposition, result, opcode + command, and conditionally
383 * sense data for failures or non SUCCESS dispositions.
385 * 2: same as 1 but for all command completions.
387 * 3: same as 2 plus dump cmd address
389 * 4: same as 3 plus dump extra junk
391 if (unlikely(scsi_logging_level)) {
392 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
393 SCSI_LOG_MLCOMPLETE_BITS);
394 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
397 sdev_printk(KERN_INFO, sdev, "done ");
399 printk("0x%p ", cmd);
401 * Dump truncated values, so we usually fit within
404 switch (disposition) {
419 * If called via scsi_times_out.
426 printk(" %8x ", cmd->result);
427 scsi_print_command(cmd);
428 if (status_byte(cmd->result) & CHECK_CONDITION) {
430 * XXX The scsi_print_sense formatting/prefix
431 * doesn't match this function.
433 scsi_print_sense("", cmd);
436 printk(KERN_INFO "scsi host busy %d failed %d\n",
437 sdev->host->host_busy,
438 sdev->host->host_failed);
446 * Assign a serial number and pid to the request for error recovery
447 * and debugging purposes. Protected by the Host_Lock of host.
449 static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
451 cmd->serial_number = host->cmd_serial_number++;
452 if (cmd->serial_number == 0)
453 cmd->serial_number = host->cmd_serial_number++;
455 cmd->pid = host->cmd_pid++;
457 cmd->pid = host->cmd_pid++;
461 * Function: scsi_dispatch_command
463 * Purpose: Dispatch a command to the low-level driver.
465 * Arguments: cmd - command block we are dispatching.
469 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
471 struct Scsi_Host *host = cmd->device->host;
472 unsigned long flags = 0;
473 unsigned long timeout;
476 /* check if the device is still usable */
477 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
478 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
479 * returns an immediate error upwards, and signals
480 * that the device is no longer present */
481 cmd->result = DID_NO_CONNECT << 16;
482 atomic_inc(&cmd->device->iorequest_cnt);
484 /* return 0 (because the command has been processed) */
488 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
489 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
491 * in SDEV_BLOCK, the command is just put back on the device
492 * queue. The suspend state has already blocked the queue so
493 * future requests should not occur until the device
494 * transitions out of the suspend state.
496 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
498 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
501 * NOTE: rtn is still zero here because we don't need the
502 * queue to be plugged on return (it's already stopped)
508 * If SCSI-2 or lower, store the LUN value in cmnd.
510 if (cmd->device->scsi_level <= SCSI_2 &&
511 cmd->device->scsi_level != SCSI_UNKNOWN) {
512 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
513 (cmd->device->lun << 5 & 0xe0);
517 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
518 * we can avoid the drive not being ready.
520 timeout = host->last_reset + MIN_RESET_DELAY;
522 if (host->resetting && time_before(jiffies, timeout)) {
523 int ticks_remaining = timeout - jiffies;
525 * NOTE: This may be executed from within an interrupt
526 * handler! This is bad, but for now, it'll do. The irq
527 * level of the interrupt handler has been masked out by the
528 * platform dependent interrupt handling code already, so the
529 * sti() here will not cause another call to the SCSI host's
530 * interrupt handler (assuming there is one irq-level per
533 while (--ticks_remaining >= 0)
534 mdelay(1 + 999 / HZ);
539 * AK: unlikely race here: for some reason the timer could
540 * expire before the serial number is set up below.
542 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
547 * We will use a queued command if possible, otherwise we will
548 * emulate the queuing and calling of completion function ourselves.
550 atomic_inc(&cmd->device->iorequest_cnt);
553 * Before we queue this command, check if the command
554 * length exceeds what the host adapter can handle.
556 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
558 printk("queuecommand : command too long.\n"));
559 cmd->result = (DID_ABORT << 16);
565 spin_lock_irqsave(host->host_lock, flags);
566 scsi_cmd_get_serial(host, cmd);
568 if (unlikely(host->shost_state == SHOST_DEL)) {
569 cmd->result = (DID_NO_CONNECT << 16);
572 rtn = host->hostt->queuecommand(cmd, scsi_done);
574 spin_unlock_irqrestore(host->host_lock, flags);
576 if (scsi_delete_timer(cmd)) {
577 atomic_inc(&cmd->device->iodone_cnt);
578 scsi_queue_insert(cmd,
579 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
580 rtn : SCSI_MLQUEUE_HOST_BUSY);
583 printk("queuecommand : request rejected\n"));
587 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
593 * Per-CPU I/O completion queue.
595 static DEFINE_PER_CPU(struct list_head, scsi_done_q);
598 * scsi_req_abort_cmd -- Request command recovery for the specified command
599 * cmd: pointer to the SCSI command of interest
601 * This function requests that SCSI Core start recovery for the
602 * command by deleting the timer and adding the command to the eh
603 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
604 * implement their own error recovery MAY ignore the timeout event if
605 * they generated scsi_req_abort_cmd.
607 void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
609 if (!scsi_delete_timer(cmd))
613 EXPORT_SYMBOL(scsi_req_abort_cmd);
616 * scsi_done - Enqueue the finished SCSI command into the done queue.
617 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
618 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
620 * This function is the mid-level's (SCSI Core) interrupt routine, which
621 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
622 * the command to the done queue for further processing.
624 * This is the producer of the done queue who enqueues at the tail.
626 * This function is interrupt context safe.
628 static void scsi_done(struct scsi_cmnd *cmd)
631 * We don't have to worry about this one timing out any more.
632 * If we are unable to remove the timer, then the command
633 * has already timed out. In which case, we have no choice but to
634 * let the timeout function run, as we have no idea where in fact
635 * that function could really be. It might be on another processor,
638 if (!scsi_delete_timer(cmd))
643 /* Private entry to scsi_done() to complete a command when the timer
644 * isn't running --- used by scsi_times_out */
645 void __scsi_done(struct scsi_cmnd *cmd)
647 struct request *rq = cmd->request;
650 * Set the serial numbers back to zero
652 cmd->serial_number = 0;
654 atomic_inc(&cmd->device->iodone_cnt);
656 atomic_inc(&cmd->device->ioerr_cnt);
661 * The uptodate/nbytes values don't matter, as we allow partial
662 * completes and thus will check this in the softirq callback
664 rq->completion_data = cmd;
665 blk_complete_request(rq);
669 * Function: scsi_retry_command
671 * Purpose: Send a command back to the low level to be retried.
673 * Notes: This command is always executed in the context of the
674 * bottom half handler, or the error handler thread. Low
675 * level drivers should not become re-entrant as a result of
678 int scsi_retry_command(struct scsi_cmnd *cmd)
681 * Zero the sense information from the last time we tried
684 memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
686 return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
690 * Function: scsi_finish_command
692 * Purpose: Pass command off to upper layer for finishing of I/O
693 * request, waking processes that are waiting on results,
696 void scsi_finish_command(struct scsi_cmnd *cmd)
698 struct scsi_device *sdev = cmd->device;
699 struct Scsi_Host *shost = sdev->host;
701 scsi_device_unbusy(sdev);
704 * Clear the flags which say that the device/host is no longer
705 * capable of accepting new commands. These are set in scsi_queue.c
706 * for both the queue full condition on a device, and for a
707 * host full condition on the host.
709 * XXX(hch): What about locking?
711 shost->host_blocked = 0;
712 sdev->device_blocked = 0;
715 * If we have valid sense information, then some kind of recovery
716 * must have taken place. Make a note of this.
718 if (SCSI_SENSE_VALID(cmd))
719 cmd->result |= (DRIVER_SENSE << 24);
721 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
722 "Notifying upper driver of completion "
723 "(result %x)\n", cmd->result));
727 EXPORT_SYMBOL(scsi_finish_command);
730 * Function: scsi_adjust_queue_depth()
732 * Purpose: Allow low level drivers to tell us to change the queue depth
733 * on a specific SCSI device
735 * Arguments: sdev - SCSI Device in question
736 * tagged - Do we use tagged queueing (non-0) or do we treat
737 * this device as an untagged device (0)
738 * tags - Number of tags allowed if tagged queueing enabled,
739 * or number of commands the low level driver can
740 * queue up in non-tagged mode (as per cmd_per_lun).
744 * Lock Status: None held on entry
746 * Notes: Low level drivers may call this at any time and we will do
747 * the right thing depending on whether or not the device is
748 * currently active and whether or not it even has the
749 * command blocks built yet.
751 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
756 * refuse to set tagged depth to an unworkable size
761 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
763 /* Check to see if the queue is managed by the block layer
764 * if it is, and we fail to adjust the depth, exit */
765 if (blk_queue_tagged(sdev->request_queue) &&
766 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
769 sdev->queue_depth = tags;
771 case MSG_ORDERED_TAG:
772 sdev->ordered_tags = 1;
773 sdev->simple_tags = 1;
776 sdev->ordered_tags = 0;
777 sdev->simple_tags = 1;
780 sdev_printk(KERN_WARNING, sdev,
781 "scsi_adjust_queue_depth, bad queue type, "
784 sdev->ordered_tags = sdev->simple_tags = 0;
785 sdev->queue_depth = tags;
789 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
791 EXPORT_SYMBOL(scsi_adjust_queue_depth);
794 * Function: scsi_track_queue_full()
796 * Purpose: This function will track successive QUEUE_FULL events on a
797 * specific SCSI device to determine if and when there is a
798 * need to adjust the queue depth on the device.
800 * Arguments: sdev - SCSI Device in question
801 * depth - Current number of outstanding SCSI commands on
802 * this device, not counting the one returned as
805 * Returns: 0 - No change needed
806 * >0 - Adjust queue depth to this new depth
807 * -1 - Drop back to untagged operation using host->cmd_per_lun
808 * as the untagged command depth
810 * Lock Status: None held on entry
812 * Notes: Low level drivers may call this at any time and we will do
813 * "The Right Thing." We are interrupt context safe.
815 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
817 if ((jiffies >> 4) == sdev->last_queue_full_time)
820 sdev->last_queue_full_time = (jiffies >> 4);
821 if (sdev->last_queue_full_depth != depth) {
822 sdev->last_queue_full_count = 1;
823 sdev->last_queue_full_depth = depth;
825 sdev->last_queue_full_count++;
828 if (sdev->last_queue_full_count <= 10)
830 if (sdev->last_queue_full_depth < 8) {
831 /* Drop back to untagged */
832 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
836 if (sdev->ordered_tags)
837 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
839 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
842 EXPORT_SYMBOL(scsi_track_queue_full);
845 * scsi_device_get - get an addition reference to a scsi_device
846 * @sdev: device to get a reference to
848 * Gets a reference to the scsi_device and increments the use count
849 * of the underlying LLDD module. You must hold host_lock of the
850 * parent Scsi_Host or already have a reference when calling this.
852 int scsi_device_get(struct scsi_device *sdev)
854 if (sdev->sdev_state == SDEV_DEL)
856 if (!get_device(&sdev->sdev_gendev))
858 /* We can fail this if we're doing SCSI operations
859 * from module exit (like cache flush) */
860 try_module_get(sdev->host->hostt->module);
864 EXPORT_SYMBOL(scsi_device_get);
867 * scsi_device_put - release a reference to a scsi_device
868 * @sdev: device to release a reference on.
870 * Release a reference to the scsi_device and decrements the use count
871 * of the underlying LLDD module. The device is freed once the last
874 void scsi_device_put(struct scsi_device *sdev)
876 struct module *module = sdev->host->hostt->module;
878 #ifdef CONFIG_MODULE_UNLOAD
879 /* The module refcount will be zero if scsi_device_get()
880 * was called from a module removal routine */
881 if (module && module_refcount(module) != 0)
884 put_device(&sdev->sdev_gendev);
886 EXPORT_SYMBOL(scsi_device_put);
888 /* helper for shost_for_each_device, thus not documented */
889 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
890 struct scsi_device *prev)
892 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
893 struct scsi_device *next = NULL;
896 spin_lock_irqsave(shost->host_lock, flags);
897 while (list->next != &shost->__devices) {
898 next = list_entry(list->next, struct scsi_device, siblings);
899 /* skip devices that we can't get a reference to */
900 if (!scsi_device_get(next))
905 spin_unlock_irqrestore(shost->host_lock, flags);
908 scsi_device_put(prev);
911 EXPORT_SYMBOL(__scsi_iterate_devices);
914 * starget_for_each_device - helper to walk all devices of a target
915 * @starget: target whose devices we want to iterate over.
917 * This traverses over each devices of @shost. The devices have
918 * a reference that must be released by scsi_host_put when breaking
921 void starget_for_each_device(struct scsi_target *starget, void * data,
922 void (*fn)(struct scsi_device *, void *))
924 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
925 struct scsi_device *sdev;
927 shost_for_each_device(sdev, shost) {
928 if ((sdev->channel == starget->channel) &&
929 (sdev->id == starget->id))
933 EXPORT_SYMBOL(starget_for_each_device);
936 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
937 * @starget: SCSI target pointer
938 * @lun: SCSI Logical Unit Number
940 * Looks up the scsi_device with the specified @lun for a give
941 * @starget. The returned scsi_device does not have an additional
942 * reference. You must hold the host's host_lock over this call and
943 * any access to the returned scsi_device.
945 * Note: The only reason why drivers would want to use this is because
946 * they're need to access the device list in irq context. Otherwise you
947 * really want to use scsi_device_lookup_by_target instead.
949 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
952 struct scsi_device *sdev;
954 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
961 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
964 * scsi_device_lookup_by_target - find a device given the target
965 * @starget: SCSI target pointer
966 * @lun: SCSI Logical Unit Number
968 * Looks up the scsi_device with the specified @channel, @id, @lun for a
969 * give host. The returned scsi_device has an additional reference that
970 * needs to be release with scsi_host_put once you're done with it.
972 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
975 struct scsi_device *sdev;
976 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
979 spin_lock_irqsave(shost->host_lock, flags);
980 sdev = __scsi_device_lookup_by_target(starget, lun);
981 if (sdev && scsi_device_get(sdev))
983 spin_unlock_irqrestore(shost->host_lock, flags);
987 EXPORT_SYMBOL(scsi_device_lookup_by_target);
990 * scsi_device_lookup - find a device given the host (UNLOCKED)
991 * @shost: SCSI host pointer
992 * @channel: SCSI channel (zero if only one channel)
993 * @pun: SCSI target number (physical unit number)
994 * @lun: SCSI Logical Unit Number
996 * Looks up the scsi_device with the specified @channel, @id, @lun for a
997 * give host. The returned scsi_device does not have an additional reference.
998 * You must hold the host's host_lock over this call and any access to the
999 * returned scsi_device.
1001 * Note: The only reason why drivers would want to use this is because
1002 * they're need to access the device list in irq context. Otherwise you
1003 * really want to use scsi_device_lookup instead.
1005 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1006 uint channel, uint id, uint lun)
1008 struct scsi_device *sdev;
1010 list_for_each_entry(sdev, &shost->__devices, siblings) {
1011 if (sdev->channel == channel && sdev->id == id &&
1018 EXPORT_SYMBOL(__scsi_device_lookup);
1021 * scsi_device_lookup - find a device given the host
1022 * @shost: SCSI host pointer
1023 * @channel: SCSI channel (zero if only one channel)
1024 * @id: SCSI target number (physical unit number)
1025 * @lun: SCSI Logical Unit Number
1027 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1028 * give host. The returned scsi_device has an additional reference that
1029 * needs to be release with scsi_host_put once you're done with it.
1031 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1032 uint channel, uint id, uint lun)
1034 struct scsi_device *sdev;
1035 unsigned long flags;
1037 spin_lock_irqsave(shost->host_lock, flags);
1038 sdev = __scsi_device_lookup(shost, channel, id, lun);
1039 if (sdev && scsi_device_get(sdev))
1041 spin_unlock_irqrestore(shost->host_lock, flags);
1045 EXPORT_SYMBOL(scsi_device_lookup);
1048 * scsi_device_cancel - cancel outstanding IO to this device
1049 * @sdev: Pointer to struct scsi_device
1050 * @recovery: Boolean instructing function to recover device or not.
1053 int scsi_device_cancel(struct scsi_device *sdev, int recovery)
1055 struct scsi_cmnd *scmd;
1056 LIST_HEAD(active_list);
1057 struct list_head *lh, *lh_sf;
1058 unsigned long flags;
1060 scsi_device_set_state(sdev, SDEV_CANCEL);
1062 spin_lock_irqsave(&sdev->list_lock, flags);
1063 list_for_each_entry(scmd, &sdev->cmd_list, list) {
1064 if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) {
1066 * If we are unable to remove the timer, it means
1067 * that the command has already timed out or
1070 if (!scsi_delete_timer(scmd))
1072 list_add_tail(&scmd->eh_entry, &active_list);
1075 spin_unlock_irqrestore(&sdev->list_lock, flags);
1077 if (!list_empty(&active_list)) {
1078 list_for_each_safe(lh, lh_sf, &active_list) {
1079 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1082 !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)) {
1083 scmd->result = (DID_ABORT << 16);
1084 scsi_finish_command(scmd);
1091 EXPORT_SYMBOL(scsi_device_cancel);
1093 MODULE_DESCRIPTION("SCSI core");
1094 MODULE_LICENSE("GPL");
1096 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1097 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1099 static int __init init_scsi(void)
1103 error = scsi_init_queue();
1106 error = scsi_init_procfs();
1109 error = scsi_init_devinfo();
1111 goto cleanup_procfs;
1112 error = scsi_init_hosts();
1114 goto cleanup_devlist;
1115 error = scsi_init_sysctl();
1118 error = scsi_sysfs_register();
1120 goto cleanup_sysctl;
1122 for_each_possible_cpu(i)
1123 INIT_LIST_HEAD(&per_cpu(scsi_done_q, i));
1125 scsi_netlink_init();
1127 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1135 scsi_exit_devinfo();
1140 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1145 static void __exit exit_scsi(void)
1147 scsi_netlink_exit();
1148 scsi_sysfs_unregister();
1151 scsi_exit_devinfo();
1156 subsys_initcall(init_scsi);
1157 module_exit(exit_scsi);