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>
58 #include <scsi/scsi.h>
59 #include <scsi/scsi_cmnd.h>
60 #include <scsi/scsi_dbg.h>
61 #include <scsi/scsi_device.h>
62 #include <scsi/scsi_driver.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 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
100 * You may not alter any existing entry (although adding new ones is
101 * encouraged once assigned by ANSI/INCITS T10
103 static const char *const scsi_device_types[] = {
126 * scsi_device_type - Return 17 char string indicating device type.
127 * @type: type number to look up
130 const char * scsi_device_type(unsigned type)
133 return "Well-known LUN ";
136 if (type >= ARRAY_SIZE(scsi_device_types))
138 return scsi_device_types[type];
141 EXPORT_SYMBOL(scsi_device_type);
143 struct scsi_host_cmd_pool {
144 struct kmem_cache *cmd_slab;
145 struct kmem_cache *sense_slab;
149 unsigned int slab_flags;
153 static struct scsi_host_cmd_pool scsi_cmd_pool = {
154 .cmd_name = "scsi_cmd_cache",
155 .sense_name = "scsi_sense_cache",
156 .slab_flags = SLAB_HWCACHE_ALIGN,
159 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
160 .cmd_name = "scsi_cmd_cache(DMA)",
161 .sense_name = "scsi_sense_cache(DMA)",
162 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
163 .gfp_mask = __GFP_DMA,
166 static DEFINE_MUTEX(host_cmd_pool_mutex);
169 * scsi_pool_alloc_command - internal function to get a fully allocated command
170 * @pool: slab pool to allocate the command from
171 * @gfp_mask: mask for the allocation
173 * Returns a fully allocated command (with the allied sense buffer) or
176 static struct scsi_cmnd *
177 scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
179 struct scsi_cmnd *cmd;
181 cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
185 memset(cmd, 0, sizeof(*cmd));
187 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
188 gfp_mask | pool->gfp_mask);
189 if (!cmd->sense_buffer) {
190 kmem_cache_free(pool->cmd_slab, cmd);
198 * scsi_pool_free_command - internal function to release a command
199 * @pool: slab pool to allocate the command from
200 * @cmd: command to release
202 * the command must previously have been allocated by
203 * scsi_pool_alloc_command.
206 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
207 struct scsi_cmnd *cmd)
209 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
210 kmem_cache_free(pool->cmd_slab, cmd);
214 * __scsi_get_command - Allocate a struct scsi_cmnd
215 * @shost: host to transmit command
216 * @gfp_mask: allocation mask
218 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
219 * host's free_list if necessary.
221 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
223 struct scsi_cmnd *cmd;
226 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
228 if (unlikely(!cmd)) {
231 spin_lock_irqsave(&shost->free_list_lock, flags);
232 if (likely(!list_empty(&shost->free_list))) {
233 cmd = list_entry(shost->free_list.next,
234 struct scsi_cmnd, list);
235 list_del_init(&cmd->list);
237 spin_unlock_irqrestore(&shost->free_list_lock, flags);
240 buf = cmd->sense_buffer;
241 memset(cmd, 0, sizeof(*cmd));
242 cmd->sense_buffer = buf;
248 EXPORT_SYMBOL_GPL(__scsi_get_command);
251 * scsi_get_command - Allocate and setup a scsi command block
252 * @dev: parent scsi device
253 * @gfp_mask: allocator flags
255 * Returns: The allocated scsi command structure.
257 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
259 struct scsi_cmnd *cmd;
261 /* Bail if we can't get a reference to the device */
262 if (!get_device(&dev->sdev_gendev))
265 cmd = __scsi_get_command(dev->host, gfp_mask);
267 if (likely(cmd != NULL)) {
271 init_timer(&cmd->eh_timeout);
272 INIT_LIST_HEAD(&cmd->list);
273 spin_lock_irqsave(&dev->list_lock, flags);
274 list_add_tail(&cmd->list, &dev->cmd_list);
275 spin_unlock_irqrestore(&dev->list_lock, flags);
276 cmd->jiffies_at_alloc = jiffies;
278 put_device(&dev->sdev_gendev);
282 EXPORT_SYMBOL(scsi_get_command);
285 * __scsi_put_command - Free a struct scsi_cmnd
287 * @cmd: Command to free
288 * @dev: parent scsi device
290 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
295 /* changing locks here, don't need to restore the irq state */
296 spin_lock_irqsave(&shost->free_list_lock, flags);
297 if (unlikely(list_empty(&shost->free_list))) {
298 list_add(&cmd->list, &shost->free_list);
301 spin_unlock_irqrestore(&shost->free_list_lock, flags);
303 if (likely(cmd != NULL))
304 scsi_pool_free_command(shost->cmd_pool, cmd);
308 EXPORT_SYMBOL(__scsi_put_command);
311 * scsi_put_command - Free a scsi command block
312 * @cmd: command block to free
316 * Notes: The command must not belong to any lists.
318 void scsi_put_command(struct scsi_cmnd *cmd)
320 struct scsi_device *sdev = cmd->device;
323 /* serious error if the command hasn't come from a device list */
324 spin_lock_irqsave(&cmd->device->list_lock, flags);
325 BUG_ON(list_empty(&cmd->list));
326 list_del_init(&cmd->list);
327 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
329 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
331 EXPORT_SYMBOL(scsi_put_command);
333 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
335 struct scsi_host_cmd_pool *retval = NULL, *pool;
337 * Select a command slab for this host and create it if not
340 mutex_lock(&host_cmd_pool_mutex);
341 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
344 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
345 sizeof(struct scsi_cmnd), 0,
346 pool->slab_flags, NULL);
350 pool->sense_slab = kmem_cache_create(pool->sense_name,
351 SCSI_SENSE_BUFFERSIZE, 0,
352 pool->slab_flags, NULL);
353 if (!pool->sense_slab) {
354 kmem_cache_destroy(pool->cmd_slab);
362 mutex_unlock(&host_cmd_pool_mutex);
366 static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
368 struct scsi_host_cmd_pool *pool;
370 mutex_lock(&host_cmd_pool_mutex);
371 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
374 * This may happen if a driver has a mismatched get and put
375 * of the command pool; the driver should be implicated in
378 BUG_ON(pool->users == 0);
380 if (!--pool->users) {
381 kmem_cache_destroy(pool->cmd_slab);
382 kmem_cache_destroy(pool->sense_slab);
384 mutex_unlock(&host_cmd_pool_mutex);
388 * scsi_allocate_command - get a fully allocated SCSI command
389 * @gfp_mask: allocation mask
391 * This function is for use outside of the normal host based pools.
392 * It allocates the relevant command and takes an additional reference
393 * on the pool it used. This function *must* be paired with
394 * scsi_free_command which also has the identical mask, otherwise the
395 * free pool counts will eventually go wrong and you'll trigger a bug.
397 * This function should *only* be used by drivers that need a static
398 * command allocation at start of day for internal functions.
400 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
402 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
407 return scsi_pool_alloc_command(pool, gfp_mask);
409 EXPORT_SYMBOL(scsi_allocate_command);
412 * scsi_free_command - free a command allocated by scsi_allocate_command
413 * @gfp_mask: mask used in the original allocation
414 * @cmd: command to free
416 * Note: using the original allocation mask is vital because that's
417 * what determines which command pool we use to free the command. Any
418 * mismatch will cause the system to BUG eventually.
420 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
422 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
425 * this could trigger if the mask to scsi_allocate_command
426 * doesn't match this mask. Otherwise we're guaranteed that this
427 * succeeds because scsi_allocate_command must have taken a reference
432 scsi_pool_free_command(pool, cmd);
434 * scsi_put_host_cmd_pool is called twice; once to release the
435 * reference we took above, and once to release the reference
436 * originally taken by scsi_allocate_command
438 scsi_put_host_cmd_pool(gfp_mask);
439 scsi_put_host_cmd_pool(gfp_mask);
441 EXPORT_SYMBOL(scsi_free_command);
444 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
445 * @shost: host to allocate the freelist for.
447 * Description: The command freelist protects against system-wide out of memory
448 * deadlock by preallocating one SCSI command structure for each host, so the
449 * system can always write to a swap file on a device associated with that host.
453 int scsi_setup_command_freelist(struct Scsi_Host *shost)
455 struct scsi_cmnd *cmd;
456 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
458 spin_lock_init(&shost->free_list_lock);
459 INIT_LIST_HEAD(&shost->free_list);
461 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
463 if (!shost->cmd_pool)
467 * Get one backup command for this host.
469 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
471 scsi_put_host_cmd_pool(gfp_mask);
472 shost->cmd_pool = NULL;
475 list_add(&cmd->list, &shost->free_list);
480 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
481 * @shost: host whose freelist is going to be destroyed
483 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
486 * If cmd_pool is NULL the free list was not initialized, so
487 * do not attempt to release resources.
489 if (!shost->cmd_pool)
492 while (!list_empty(&shost->free_list)) {
493 struct scsi_cmnd *cmd;
495 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
496 list_del_init(&cmd->list);
497 scsi_pool_free_command(shost->cmd_pool, cmd);
499 shost->cmd_pool = NULL;
500 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
503 #ifdef CONFIG_SCSI_LOGGING
504 void scsi_log_send(struct scsi_cmnd *cmd)
509 * If ML QUEUE log level is greater than or equal to:
511 * 1: nothing (match completion)
513 * 2: log opcode + command of all commands
515 * 3: same as 2 plus dump cmd address
517 * 4: same as 3 plus dump extra junk
519 if (unlikely(scsi_logging_level)) {
520 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
521 SCSI_LOG_MLQUEUE_BITS);
523 scmd_printk(KERN_INFO, cmd, "Send: ");
525 printk("0x%p ", cmd);
527 scsi_print_command(cmd);
529 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
530 " queuecommand 0x%p\n",
531 scsi_sglist(cmd), scsi_bufflen(cmd),
532 cmd->device->host->hostt->queuecommand);
539 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
544 * If ML COMPLETE log level is greater than or equal to:
546 * 1: log disposition, result, opcode + command, and conditionally
547 * sense data for failures or non SUCCESS dispositions.
549 * 2: same as 1 but for all command completions.
551 * 3: same as 2 plus dump cmd address
553 * 4: same as 3 plus dump extra junk
555 if (unlikely(scsi_logging_level)) {
556 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
557 SCSI_LOG_MLCOMPLETE_BITS);
558 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
560 scmd_printk(KERN_INFO, cmd, "Done: ");
562 printk("0x%p ", cmd);
564 * Dump truncated values, so we usually fit within
567 switch (disposition) {
582 * If called via scsi_times_out.
589 scsi_print_result(cmd);
590 scsi_print_command(cmd);
591 if (status_byte(cmd->result) & CHECK_CONDITION)
592 scsi_print_sense("", cmd);
594 scmd_printk(KERN_INFO, cmd,
595 "scsi host busy %d failed %d\n",
596 cmd->device->host->host_busy,
597 cmd->device->host->host_failed);
604 * scsi_cmd_get_serial - Assign a serial number to a command
605 * @host: the scsi host
606 * @cmd: command to assign serial number to
608 * Description: a serial number identifies a request for error recovery
609 * and debugging purposes. Protected by the Host_Lock of host.
611 static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
613 cmd->serial_number = host->cmd_serial_number++;
614 if (cmd->serial_number == 0)
615 cmd->serial_number = host->cmd_serial_number++;
619 * scsi_dispatch_command - Dispatch a command to the low-level driver.
620 * @cmd: command block we are dispatching.
622 * Return: nonzero return request was rejected and device's queue needs to be
625 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
627 struct Scsi_Host *host = cmd->device->host;
628 unsigned long flags = 0;
629 unsigned long timeout;
632 /* check if the device is still usable */
633 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
634 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
635 * returns an immediate error upwards, and signals
636 * that the device is no longer present */
637 cmd->result = DID_NO_CONNECT << 16;
638 atomic_inc(&cmd->device->iorequest_cnt);
640 /* return 0 (because the command has been processed) */
644 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
645 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
647 * in SDEV_BLOCK, the command is just put back on the device
648 * queue. The suspend state has already blocked the queue so
649 * future requests should not occur until the device
650 * transitions out of the suspend state.
652 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
654 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
657 * NOTE: rtn is still zero here because we don't need the
658 * queue to be plugged on return (it's already stopped)
664 * If SCSI-2 or lower, store the LUN value in cmnd.
666 if (cmd->device->scsi_level <= SCSI_2 &&
667 cmd->device->scsi_level != SCSI_UNKNOWN) {
668 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
669 (cmd->device->lun << 5 & 0xe0);
673 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
674 * we can avoid the drive not being ready.
676 timeout = host->last_reset + MIN_RESET_DELAY;
678 if (host->resetting && time_before(jiffies, timeout)) {
679 int ticks_remaining = timeout - jiffies;
681 * NOTE: This may be executed from within an interrupt
682 * handler! This is bad, but for now, it'll do. The irq
683 * level of the interrupt handler has been masked out by the
684 * platform dependent interrupt handling code already, so the
685 * sti() here will not cause another call to the SCSI host's
686 * interrupt handler (assuming there is one irq-level per
689 while (--ticks_remaining >= 0)
690 mdelay(1 + 999 / HZ);
695 * AK: unlikely race here: for some reason the timer could
696 * expire before the serial number is set up below.
698 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
703 * We will use a queued command if possible, otherwise we will
704 * emulate the queuing and calling of completion function ourselves.
706 atomic_inc(&cmd->device->iorequest_cnt);
709 * Before we queue this command, check if the command
710 * length exceeds what the host adapter can handle.
712 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
714 printk("queuecommand : command too long.\n"));
715 cmd->result = (DID_ABORT << 16);
721 spin_lock_irqsave(host->host_lock, flags);
722 scsi_cmd_get_serial(host, cmd);
724 if (unlikely(host->shost_state == SHOST_DEL)) {
725 cmd->result = (DID_NO_CONNECT << 16);
728 rtn = host->hostt->queuecommand(cmd, scsi_done);
730 spin_unlock_irqrestore(host->host_lock, flags);
732 if (scsi_delete_timer(cmd)) {
733 atomic_inc(&cmd->device->iodone_cnt);
734 scsi_queue_insert(cmd,
735 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
736 rtn : SCSI_MLQUEUE_HOST_BUSY);
739 printk("queuecommand : request rejected\n"));
743 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
748 * scsi_req_abort_cmd -- Request command recovery for the specified command
749 * @cmd: pointer to the SCSI command of interest
751 * This function requests that SCSI Core start recovery for the
752 * command by deleting the timer and adding the command to the eh
753 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
754 * implement their own error recovery MAY ignore the timeout event if
755 * they generated scsi_req_abort_cmd.
757 void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
759 if (!scsi_delete_timer(cmd))
763 EXPORT_SYMBOL(scsi_req_abort_cmd);
766 * scsi_done - Enqueue the finished SCSI command into the done queue.
767 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
768 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
770 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
771 * which regains ownership of the SCSI command (de facto) from a LLDD, and
772 * enqueues the command to the done queue for further processing.
774 * This is the producer of the done queue who enqueues at the tail.
776 * This function is interrupt context safe.
778 static void scsi_done(struct scsi_cmnd *cmd)
781 * We don't have to worry about this one timing out anymore.
782 * If we are unable to remove the timer, then the command
783 * has already timed out. In which case, we have no choice but to
784 * let the timeout function run, as we have no idea where in fact
785 * that function could really be. It might be on another processor,
788 if (!scsi_delete_timer(cmd))
793 /* Private entry to scsi_done() to complete a command when the timer
794 * isn't running --- used by scsi_times_out */
795 void __scsi_done(struct scsi_cmnd *cmd)
797 struct request *rq = cmd->request;
800 * Set the serial numbers back to zero
802 cmd->serial_number = 0;
804 atomic_inc(&cmd->device->iodone_cnt);
806 atomic_inc(&cmd->device->ioerr_cnt);
811 * The uptodate/nbytes values don't matter, as we allow partial
812 * completes and thus will check this in the softirq callback
814 rq->completion_data = cmd;
815 blk_complete_request(rq);
818 /* Move this to a header if it becomes more generally useful */
819 static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
821 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
825 * scsi_finish_command - cleanup and pass command back to upper layer
828 * Description: Pass command off to upper layer for finishing of I/O
829 * request, waking processes that are waiting on results,
832 void scsi_finish_command(struct scsi_cmnd *cmd)
834 struct scsi_device *sdev = cmd->device;
835 struct Scsi_Host *shost = sdev->host;
836 struct scsi_driver *drv;
837 unsigned int good_bytes;
839 scsi_device_unbusy(sdev);
842 * Clear the flags which say that the device/host is no longer
843 * capable of accepting new commands. These are set in scsi_queue.c
844 * for both the queue full condition on a device, and for a
845 * host full condition on the host.
847 * XXX(hch): What about locking?
849 shost->host_blocked = 0;
850 sdev->device_blocked = 0;
853 * If we have valid sense information, then some kind of recovery
854 * must have taken place. Make a note of this.
856 if (SCSI_SENSE_VALID(cmd))
857 cmd->result |= (DRIVER_SENSE << 24);
859 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
860 "Notifying upper driver of completion "
861 "(result %x)\n", cmd->result));
863 good_bytes = scsi_bufflen(cmd);
864 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
865 drv = scsi_cmd_to_driver(cmd);
867 good_bytes = drv->done(cmd);
869 scsi_io_completion(cmd, good_bytes);
871 EXPORT_SYMBOL(scsi_finish_command);
874 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
875 * @sdev: SCSI Device in question
876 * @tagged: Do we use tagged queueing (non-0) or do we treat
877 * this device as an untagged device (0)
878 * @tags: Number of tags allowed if tagged queueing enabled,
879 * or number of commands the low level driver can
880 * queue up in non-tagged mode (as per cmd_per_lun).
884 * Lock Status: None held on entry
886 * Notes: Low level drivers may call this at any time and we will do
887 * the right thing depending on whether or not the device is
888 * currently active and whether or not it even has the
889 * command blocks built yet.
891 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
896 * refuse to set tagged depth to an unworkable size
901 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
903 /* Check to see if the queue is managed by the block layer.
904 * If it is, and we fail to adjust the depth, exit. */
905 if (blk_queue_tagged(sdev->request_queue) &&
906 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
909 sdev->queue_depth = tags;
911 case MSG_ORDERED_TAG:
912 sdev->ordered_tags = 1;
913 sdev->simple_tags = 1;
916 sdev->ordered_tags = 0;
917 sdev->simple_tags = 1;
920 sdev_printk(KERN_WARNING, sdev,
921 "scsi_adjust_queue_depth, bad queue type, "
924 sdev->ordered_tags = sdev->simple_tags = 0;
925 sdev->queue_depth = tags;
929 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
931 EXPORT_SYMBOL(scsi_adjust_queue_depth);
934 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
935 * @sdev: SCSI Device in question
936 * @depth: Current number of outstanding SCSI commands on this device,
937 * not counting the one returned as QUEUE_FULL.
939 * Description: This function will track successive QUEUE_FULL events on a
940 * specific SCSI device to determine if and when there is a
941 * need to adjust the queue depth on the device.
943 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
944 * -1 - Drop back to untagged operation using host->cmd_per_lun
945 * as the untagged command depth
947 * Lock Status: None held on entry
949 * Notes: Low level drivers may call this at any time and we will do
950 * "The Right Thing." We are interrupt context safe.
952 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
954 if ((jiffies >> 4) == sdev->last_queue_full_time)
957 sdev->last_queue_full_time = (jiffies >> 4);
958 if (sdev->last_queue_full_depth != depth) {
959 sdev->last_queue_full_count = 1;
960 sdev->last_queue_full_depth = depth;
962 sdev->last_queue_full_count++;
965 if (sdev->last_queue_full_count <= 10)
967 if (sdev->last_queue_full_depth < 8) {
968 /* Drop back to untagged */
969 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
973 if (sdev->ordered_tags)
974 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
976 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
979 EXPORT_SYMBOL(scsi_track_queue_full);
982 * scsi_device_get - get an additional reference to a scsi_device
983 * @sdev: device to get a reference to
985 * Description: Gets a reference to the scsi_device and increments the use count
986 * of the underlying LLDD module. You must hold host_lock of the
987 * parent Scsi_Host or already have a reference when calling this.
989 int scsi_device_get(struct scsi_device *sdev)
991 if (sdev->sdev_state == SDEV_DEL)
993 if (!get_device(&sdev->sdev_gendev))
995 /* We can fail this if we're doing SCSI operations
996 * from module exit (like cache flush) */
997 try_module_get(sdev->host->hostt->module);
1001 EXPORT_SYMBOL(scsi_device_get);
1004 * scsi_device_put - release a reference to a scsi_device
1005 * @sdev: device to release a reference on.
1007 * Description: Release a reference to the scsi_device and decrements the use
1008 * count of the underlying LLDD module. The device is freed once the last
1011 void scsi_device_put(struct scsi_device *sdev)
1013 #ifdef CONFIG_MODULE_UNLOAD
1014 struct module *module = sdev->host->hostt->module;
1016 /* The module refcount will be zero if scsi_device_get()
1017 * was called from a module removal routine */
1018 if (module && module_refcount(module) != 0)
1021 put_device(&sdev->sdev_gendev);
1023 EXPORT_SYMBOL(scsi_device_put);
1025 /* helper for shost_for_each_device, see that for documentation */
1026 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1027 struct scsi_device *prev)
1029 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1030 struct scsi_device *next = NULL;
1031 unsigned long flags;
1033 spin_lock_irqsave(shost->host_lock, flags);
1034 while (list->next != &shost->__devices) {
1035 next = list_entry(list->next, struct scsi_device, siblings);
1036 /* skip devices that we can't get a reference to */
1037 if (!scsi_device_get(next))
1042 spin_unlock_irqrestore(shost->host_lock, flags);
1045 scsi_device_put(prev);
1048 EXPORT_SYMBOL(__scsi_iterate_devices);
1051 * starget_for_each_device - helper to walk all devices of a target
1052 * @starget: target whose devices we want to iterate over.
1053 * @data: Opaque passed to each function call.
1054 * @fn: Function to call on each device
1056 * This traverses over each device of @starget. The devices have
1057 * a reference that must be released by scsi_host_put when breaking
1060 void starget_for_each_device(struct scsi_target *starget, void *data,
1061 void (*fn)(struct scsi_device *, void *))
1063 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1064 struct scsi_device *sdev;
1066 shost_for_each_device(sdev, shost) {
1067 if ((sdev->channel == starget->channel) &&
1068 (sdev->id == starget->id))
1072 EXPORT_SYMBOL(starget_for_each_device);
1075 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1076 * @starget: target whose devices we want to iterate over.
1077 * @data: parameter for callback @fn()
1078 * @fn: callback function that is invoked for each device
1080 * This traverses over each device of @starget. It does _not_
1081 * take a reference on the scsi_device, so the whole loop must be
1082 * protected by shost->host_lock.
1084 * Note: The only reason why drivers would want to use this is because
1085 * they need to access the device list in irq context. Otherwise you
1086 * really want to use starget_for_each_device instead.
1088 void __starget_for_each_device(struct scsi_target *starget, void *data,
1089 void (*fn)(struct scsi_device *, void *))
1091 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1092 struct scsi_device *sdev;
1094 __shost_for_each_device(sdev, shost) {
1095 if ((sdev->channel == starget->channel) &&
1096 (sdev->id == starget->id))
1100 EXPORT_SYMBOL(__starget_for_each_device);
1103 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1104 * @starget: SCSI target pointer
1105 * @lun: SCSI Logical Unit Number
1107 * Description: Looks up the scsi_device with the specified @lun for a given
1108 * @starget. The returned scsi_device does not have an additional
1109 * reference. You must hold the host's host_lock over this call and
1110 * any access to the returned scsi_device.
1112 * Note: The only reason why drivers should use this is because
1113 * they need to access the device list in irq context. Otherwise you
1114 * really want to use scsi_device_lookup_by_target instead.
1116 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1119 struct scsi_device *sdev;
1121 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1122 if (sdev->lun ==lun)
1128 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1131 * scsi_device_lookup_by_target - find a device given the target
1132 * @starget: SCSI target pointer
1133 * @lun: SCSI Logical Unit Number
1135 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1136 * for a given host. The returned scsi_device has an additional reference that
1137 * needs to be released with scsi_device_put once you're done with it.
1139 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1142 struct scsi_device *sdev;
1143 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1144 unsigned long flags;
1146 spin_lock_irqsave(shost->host_lock, flags);
1147 sdev = __scsi_device_lookup_by_target(starget, lun);
1148 if (sdev && scsi_device_get(sdev))
1150 spin_unlock_irqrestore(shost->host_lock, flags);
1154 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1157 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1158 * @shost: SCSI host pointer
1159 * @channel: SCSI channel (zero if only one channel)
1160 * @id: SCSI target number (physical unit number)
1161 * @lun: SCSI Logical Unit Number
1163 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1164 * for a given host. The returned scsi_device does not have an additional
1165 * reference. You must hold the host's host_lock over this call and any access
1166 * to the returned scsi_device.
1168 * Note: The only reason why drivers would want to use this is because
1169 * they need to access the device list in irq context. Otherwise you
1170 * really want to use scsi_device_lookup instead.
1172 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1173 uint channel, uint id, uint lun)
1175 struct scsi_device *sdev;
1177 list_for_each_entry(sdev, &shost->__devices, siblings) {
1178 if (sdev->channel == channel && sdev->id == id &&
1185 EXPORT_SYMBOL(__scsi_device_lookup);
1188 * scsi_device_lookup - find a device given the host
1189 * @shost: SCSI host pointer
1190 * @channel: SCSI channel (zero if only one channel)
1191 * @id: SCSI target number (physical unit number)
1192 * @lun: SCSI Logical Unit Number
1194 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1195 * for a given host. The returned scsi_device has an additional reference that
1196 * needs to be released with scsi_device_put once you're done with it.
1198 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1199 uint channel, uint id, uint lun)
1201 struct scsi_device *sdev;
1202 unsigned long flags;
1204 spin_lock_irqsave(shost->host_lock, flags);
1205 sdev = __scsi_device_lookup(shost, channel, id, lun);
1206 if (sdev && scsi_device_get(sdev))
1208 spin_unlock_irqrestore(shost->host_lock, flags);
1212 EXPORT_SYMBOL(scsi_device_lookup);
1214 MODULE_DESCRIPTION("SCSI core");
1215 MODULE_LICENSE("GPL");
1217 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1218 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1220 static int __init init_scsi(void)
1224 error = scsi_init_queue();
1227 error = scsi_init_procfs();
1230 error = scsi_init_devinfo();
1232 goto cleanup_procfs;
1233 error = scsi_init_hosts();
1235 goto cleanup_devlist;
1236 error = scsi_init_sysctl();
1239 error = scsi_sysfs_register();
1241 goto cleanup_sysctl;
1243 scsi_netlink_init();
1245 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1253 scsi_exit_devinfo();
1258 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1263 static void __exit exit_scsi(void)
1265 scsi_netlink_exit();
1266 scsi_sysfs_unregister();
1269 scsi_exit_devinfo();
1274 subsys_initcall(init_scsi);
1275 module_exit(exit_scsi);