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/devfs_fs_kernel.h>
52 #include <linux/unistd.h>
53 #include <linux/spinlock.h>
54 #include <linux/kmod.h>
55 #include <linux/interrupt.h>
56 #include <linux/notifier.h>
57 #include <linux/cpu.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>
66 #include <scsi/scsi_request.h>
68 #include "scsi_priv.h"
69 #include "scsi_logging.h"
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)
93 unsigned long scsi_pid;
94 static unsigned long serial_number;
97 * Note - the initial logging level can be set here to log events at boot time.
98 * After the system is up, you may enable logging via the /proc interface.
100 unsigned int scsi_logging_level;
102 const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] = {
120 * Function: scsi_allocate_request
122 * Purpose: Allocate a request descriptor.
124 * Arguments: device - device for which we want a request
125 * gfp_mask - allocation flags passed to kmalloc
127 * Lock status: No locks assumed to be held. This function is SMP-safe.
129 * Returns: Pointer to request block.
131 struct scsi_request *scsi_allocate_request(struct scsi_device *sdev,
134 const int offset = ALIGN(sizeof(struct scsi_request), 4);
135 const int size = offset + sizeof(struct request);
136 struct scsi_request *sreq;
138 sreq = kmalloc(size, gfp_mask);
139 if (likely(sreq != NULL)) {
140 memset(sreq, 0, size);
141 sreq->sr_request = (struct request *)(((char *)sreq) + offset);
142 sreq->sr_device = sdev;
143 sreq->sr_host = sdev->host;
144 sreq->sr_magic = SCSI_REQ_MAGIC;
145 sreq->sr_data_direction = DMA_BIDIRECTIONAL;
151 void __scsi_release_request(struct scsi_request *sreq)
153 struct request *req = sreq->sr_request;
155 /* unlikely because the tag was usually ended earlier by the
156 * mid-layer. However, for layering reasons ULD's don't end
157 * the tag of commands they generate. */
158 if (unlikely(blk_rq_tagged(req))) {
160 struct request_queue *q = req->q;
162 spin_lock_irqsave(q->queue_lock, flags);
163 blk_queue_end_tag(q, req);
164 spin_unlock_irqrestore(q->queue_lock, flags);
168 if (likely(sreq->sr_command != NULL)) {
169 struct scsi_cmnd *cmd = sreq->sr_command;
171 sreq->sr_command = NULL;
172 scsi_next_command(cmd);
177 * Function: scsi_release_request
179 * Purpose: Release a request descriptor.
181 * Arguments: sreq - request to release
183 * Lock status: No locks assumed to be held. This function is SMP-safe.
185 void scsi_release_request(struct scsi_request *sreq)
187 __scsi_release_request(sreq);
191 struct scsi_host_cmd_pool {
195 unsigned int slab_flags;
196 unsigned int gfp_mask;
199 static struct scsi_host_cmd_pool scsi_cmd_pool = {
200 .name = "scsi_cmd_cache",
201 .slab_flags = SLAB_HWCACHE_ALIGN,
204 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
205 .name = "scsi_cmd_cache(DMA)",
206 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
207 .gfp_mask = __GFP_DMA,
210 static DECLARE_MUTEX(host_cmd_pool_mutex);
212 static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost,
215 struct scsi_cmnd *cmd;
217 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
218 gfp_mask | shost->cmd_pool->gfp_mask);
220 if (unlikely(!cmd)) {
223 spin_lock_irqsave(&shost->free_list_lock, flags);
224 if (likely(!list_empty(&shost->free_list))) {
225 cmd = list_entry(shost->free_list.next,
226 struct scsi_cmnd, list);
227 list_del_init(&cmd->list);
229 spin_unlock_irqrestore(&shost->free_list_lock, flags);
236 * Function: scsi_get_command()
238 * Purpose: Allocate and setup a scsi command block
240 * Arguments: dev - parent scsi device
241 * gfp_mask- allocator flags
243 * Returns: The allocated scsi command structure.
245 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, int gfp_mask)
247 struct scsi_cmnd *cmd;
249 /* Bail if we can't get a reference to the device */
250 if (!get_device(&dev->sdev_gendev))
253 cmd = __scsi_get_command(dev->host, gfp_mask);
255 if (likely(cmd != NULL)) {
258 memset(cmd, 0, sizeof(*cmd));
260 cmd->state = SCSI_STATE_UNUSED;
261 cmd->owner = SCSI_OWNER_NOBODY;
262 init_timer(&cmd->eh_timeout);
263 INIT_LIST_HEAD(&cmd->list);
264 spin_lock_irqsave(&dev->list_lock, flags);
265 list_add_tail(&cmd->list, &dev->cmd_list);
266 spin_unlock_irqrestore(&dev->list_lock, flags);
268 put_device(&dev->sdev_gendev);
274 * Function: scsi_put_command()
276 * Purpose: Free a scsi command block
278 * Arguments: cmd - command block to free
282 * Notes: The command must not belong to any lists.
284 void scsi_put_command(struct scsi_cmnd *cmd)
286 struct scsi_device *sdev = cmd->device;
287 struct Scsi_Host *shost = sdev->host;
290 /* serious error if the command hasn't come from a device list */
291 spin_lock_irqsave(&cmd->device->list_lock, flags);
292 BUG_ON(list_empty(&cmd->list));
293 list_del_init(&cmd->list);
294 spin_unlock(&cmd->device->list_lock);
295 /* changing locks here, don't need to restore the irq state */
296 spin_lock(&shost->free_list_lock);
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 kmem_cache_free(shost->cmd_pool->slab, cmd);
306 put_device(&sdev->sdev_gendev);
310 * Function: scsi_setup_command_freelist()
312 * Purpose: Setup the command freelist for a scsi host.
314 * Arguments: shost - host to allocate the freelist for.
318 int scsi_setup_command_freelist(struct Scsi_Host *shost)
320 struct scsi_host_cmd_pool *pool;
321 struct scsi_cmnd *cmd;
323 spin_lock_init(&shost->free_list_lock);
324 INIT_LIST_HEAD(&shost->free_list);
327 * Select a command slab for this host and create it if not
330 down(&host_cmd_pool_mutex);
331 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
333 pool->slab = kmem_cache_create(pool->name,
334 sizeof(struct scsi_cmnd), 0,
335 pool->slab_flags, NULL, NULL);
341 shost->cmd_pool = pool;
342 up(&host_cmd_pool_mutex);
345 * Get one backup command for this host.
347 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
348 GFP_KERNEL | shost->cmd_pool->gfp_mask);
351 list_add(&cmd->list, &shost->free_list);
356 kmem_cache_destroy(pool->slab);
359 up(&host_cmd_pool_mutex);
365 * Function: scsi_destroy_command_freelist()
367 * Purpose: Release the command freelist for a scsi host.
369 * Arguments: shost - host that's freelist is going to be destroyed
371 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
373 while (!list_empty(&shost->free_list)) {
374 struct scsi_cmnd *cmd;
376 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
377 list_del_init(&cmd->list);
378 kmem_cache_free(shost->cmd_pool->slab, cmd);
381 down(&host_cmd_pool_mutex);
382 if (!--shost->cmd_pool->users)
383 kmem_cache_destroy(shost->cmd_pool->slab);
384 up(&host_cmd_pool_mutex);
387 #ifdef CONFIG_SCSI_LOGGING
388 void scsi_log_send(struct scsi_cmnd *cmd)
391 struct scsi_device *sdev;
394 * If ML QUEUE log level is greater than or equal to:
396 * 1: nothing (match completion)
398 * 2: log opcode + command of all commands
400 * 3: same as 2 plus dump cmd address
402 * 4: same as 3 plus dump extra junk
404 if (unlikely(scsi_logging_level)) {
405 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
406 SCSI_LOG_MLQUEUE_BITS);
409 printk(KERN_INFO "scsi <%d:%d:%d:%d> send ",
410 sdev->host->host_no, sdev->channel, sdev->id,
413 printk("0x%p ", cmd);
415 * spaces to match disposition and cmd->result
416 * output in scsi_log_completion.
419 scsi_print_command(cmd);
421 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
422 " done = 0x%p, queuecommand 0x%p\n",
423 cmd->buffer, cmd->bufflen,
425 sdev->host->hostt->queuecommand);
432 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
435 struct scsi_device *sdev;
438 * If ML COMPLETE log level is greater than or equal to:
440 * 1: log disposition, result, opcode + command, and conditionally
441 * sense data for failures or non SUCCESS dispositions.
443 * 2: same as 1 but for all command completions.
445 * 3: same as 2 plus dump cmd address
447 * 4: same as 3 plus dump extra junk
449 if (unlikely(scsi_logging_level)) {
450 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
451 SCSI_LOG_MLCOMPLETE_BITS);
452 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
455 printk(KERN_INFO "scsi <%d:%d:%d:%d> done ",
456 sdev->host->host_no, sdev->channel, sdev->id,
459 printk("0x%p ", cmd);
461 * Dump truncated values, so we usually fit within
464 switch (disposition) {
479 * If called via scsi_times_out.
486 printk(" %8x ", cmd->result);
487 scsi_print_command(cmd);
488 if (status_byte(cmd->result) & CHECK_CONDITION) {
490 * XXX The print_sense formatting/prefix
491 * doesn't match this function.
493 scsi_print_sense("", cmd);
496 printk(KERN_INFO "scsi host busy %d failed %d\n",
497 sdev->host->host_busy,
498 sdev->host->host_failed);
506 * Function: scsi_dispatch_command
508 * Purpose: Dispatch a command to the low-level driver.
510 * Arguments: cmd - command block we are dispatching.
514 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
516 struct Scsi_Host *host = cmd->device->host;
517 unsigned long flags = 0;
518 unsigned long timeout;
521 /* check if the device is still usable */
522 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
523 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
524 * returns an immediate error upwards, and signals
525 * that the device is no longer present */
526 cmd->result = DID_NO_CONNECT << 16;
528 /* return 0 (because the command has been processed) */
532 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
533 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
535 * in SDEV_BLOCK, the command is just put back on the device
536 * queue. The suspend state has already blocked the queue so
537 * future requests should not occur until the device
538 * transitions out of the suspend state.
540 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
542 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
545 * NOTE: rtn is still zero here because we don't need the
546 * queue to be plugged on return (it's already stopped)
551 /* Assign a unique nonzero serial_number. */
552 /* XXX(hch): this is racy */
553 if (++serial_number == 0)
555 cmd->serial_number = serial_number;
556 cmd->pid = scsi_pid++;
559 * If SCSI-2 or lower, store the LUN value in cmnd.
561 if (cmd->device->scsi_level <= SCSI_2) {
562 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
563 (cmd->device->lun << 5 & 0xe0);
567 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
568 * we can avoid the drive not being ready.
570 timeout = host->last_reset + MIN_RESET_DELAY;
572 if (host->resetting && time_before(jiffies, timeout)) {
573 int ticks_remaining = timeout - jiffies;
575 * NOTE: This may be executed from within an interrupt
576 * handler! This is bad, but for now, it'll do. The irq
577 * level of the interrupt handler has been masked out by the
578 * platform dependent interrupt handling code already, so the
579 * sti() here will not cause another call to the SCSI host's
580 * interrupt handler (assuming there is one irq-level per
583 while (--ticks_remaining >= 0)
584 mdelay(1 + 999 / HZ);
588 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
593 * We will use a queued command if possible, otherwise we will
594 * emulate the queuing and calling of completion function ourselves.
597 cmd->state = SCSI_STATE_QUEUED;
598 cmd->owner = SCSI_OWNER_LOWLEVEL;
601 * Before we queue this command, check if the command
602 * length exceeds what the host adapter can handle.
604 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
606 printk("queuecommand : command too long.\n"));
607 cmd->result = (DID_ABORT << 16);
609 spin_lock_irqsave(host->host_lock, flags);
611 spin_unlock_irqrestore(host->host_lock, flags);
615 spin_lock_irqsave(host->host_lock, flags);
616 if (unlikely(test_bit(SHOST_CANCEL, &host->shost_state))) {
617 cmd->result = (DID_NO_CONNECT << 16);
620 rtn = host->hostt->queuecommand(cmd, scsi_done);
622 spin_unlock_irqrestore(host->host_lock, flags);
624 scsi_queue_insert(cmd,
625 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
626 rtn : SCSI_MLQUEUE_HOST_BUSY);
628 printk("queuecommand : request rejected\n"));
632 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
637 * Function: scsi_init_cmd_from_req
639 * Purpose: Queue a SCSI command
640 * Purpose: Initialize a struct scsi_cmnd from a struct scsi_request
642 * Arguments: cmd - command descriptor.
643 * sreq - Request from the queue.
645 * Lock status: None needed.
649 * Notes: Mainly transfer data from the request structure to the
650 * command structure. The request structure is allocated
651 * using the normal memory allocator, and requests can pile
652 * up to more or less any depth. The command structure represents
653 * a consumable resource, as these are allocated into a pool
654 * when the SCSI subsystem initializes. The preallocation is
655 * required so that in low-memory situations a disk I/O request
656 * won't cause the memory manager to try and write out a page.
657 * The request structure is generally used by ioctls and character
660 void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq)
662 sreq->sr_command = cmd;
664 cmd->owner = SCSI_OWNER_MIDLEVEL;
665 cmd->cmd_len = sreq->sr_cmd_len;
666 cmd->use_sg = sreq->sr_use_sg;
668 cmd->request = sreq->sr_request;
669 memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd));
670 cmd->serial_number = 0;
671 cmd->serial_number_at_timeout = 0;
672 cmd->bufflen = sreq->sr_bufflen;
673 cmd->buffer = sreq->sr_buffer;
675 cmd->allowed = sreq->sr_allowed;
676 cmd->done = sreq->sr_done;
677 cmd->timeout_per_command = sreq->sr_timeout_per_command;
678 cmd->sc_data_direction = sreq->sr_data_direction;
679 cmd->sglist_len = sreq->sr_sglist_len;
680 cmd->underflow = sreq->sr_underflow;
681 cmd->sc_request = sreq;
682 memcpy(cmd->cmnd, sreq->sr_cmnd, sizeof(sreq->sr_cmnd));
685 * Zero the sense buffer. Some host adapters automatically request
686 * sense on error. 0 is not a valid sense code.
688 memset(cmd->sense_buffer, 0, sizeof(sreq->sr_sense_buffer));
689 cmd->request_buffer = sreq->sr_buffer;
690 cmd->request_bufflen = sreq->sr_bufflen;
691 cmd->old_use_sg = cmd->use_sg;
692 if (cmd->cmd_len == 0)
693 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
694 cmd->old_cmd_len = cmd->cmd_len;
695 cmd->sc_old_data_direction = cmd->sc_data_direction;
696 cmd->old_underflow = cmd->underflow;
699 * Start the timer ticking.
701 cmd->internal_timeout = NORMAL_TIMEOUT;
702 cmd->abort_reason = 0;
705 SCSI_LOG_MLQUEUE(3, printk("Leaving scsi_init_cmd_from_req()\n"));
709 * Per-CPU I/O completion queue.
711 static DEFINE_PER_CPU(struct list_head, scsi_done_q);
714 * scsi_done - Enqueue the finished SCSI command into the done queue.
715 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
716 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
718 * This function is the mid-level's (SCSI Core) interrupt routine, which
719 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
720 * the command to the done queue for further processing.
722 * This is the producer of the done queue who enqueues at the tail.
724 * This function is interrupt context safe.
726 void scsi_done(struct scsi_cmnd *cmd)
729 * We don't have to worry about this one timing out any more.
730 * If we are unable to remove the timer, then the command
731 * has already timed out. In which case, we have no choice but to
732 * let the timeout function run, as we have no idea where in fact
733 * that function could really be. It might be on another processor,
736 if (!scsi_delete_timer(cmd))
741 /* Private entry to scsi_done() to complete a command when the timer
742 * isn't running --- used by scsi_times_out */
743 void __scsi_done(struct scsi_cmnd *cmd)
748 * Set the serial numbers back to zero
750 cmd->serial_number = 0;
751 cmd->serial_number_at_timeout = 0;
752 cmd->state = SCSI_STATE_BHQUEUE;
753 cmd->owner = SCSI_OWNER_BH_HANDLER;
756 * Next, enqueue the command into the done queue.
757 * It is a per-CPU queue, so we just disable local interrupts
758 * and need no spinlock.
760 local_irq_save(flags);
761 list_add_tail(&cmd->eh_entry, &__get_cpu_var(scsi_done_q));
762 raise_softirq_irqoff(SCSI_SOFTIRQ);
763 local_irq_restore(flags);
767 * scsi_softirq - Perform post-interrupt processing of finished SCSI commands.
769 * This is the consumer of the done queue.
771 * This is called with all interrupts enabled. This should reduce
772 * interrupt latency, stack depth, and reentrancy of the low-level
775 static void scsi_softirq(struct softirq_action *h)
781 list_splice_init(&__get_cpu_var(scsi_done_q), &local_q);
784 while (!list_empty(&local_q)) {
785 struct scsi_cmnd *cmd = list_entry(local_q.next,
786 struct scsi_cmnd, eh_entry);
787 list_del_init(&cmd->eh_entry);
789 disposition = scsi_decide_disposition(cmd);
790 scsi_log_completion(cmd, disposition);
791 switch (disposition) {
793 scsi_finish_command(cmd);
796 scsi_retry_command(cmd);
799 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
802 if (!scsi_eh_scmd_add(cmd, 0))
803 scsi_finish_command(cmd);
809 * Function: scsi_retry_command
811 * Purpose: Send a command back to the low level to be retried.
813 * Notes: This command is always executed in the context of the
814 * bottom half handler, or the error handler thread. Low
815 * level drivers should not become re-entrant as a result of
818 int scsi_retry_command(struct scsi_cmnd *cmd)
821 * Restore the SCSI command state.
823 scsi_setup_cmd_retry(cmd);
826 * Zero the sense information from the last time we tried
829 memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
831 return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
835 * Function: scsi_finish_command
837 * Purpose: Pass command off to upper layer for finishing of I/O
838 * request, waking processes that are waiting on results,
841 void scsi_finish_command(struct scsi_cmnd *cmd)
843 struct scsi_device *sdev = cmd->device;
844 struct Scsi_Host *shost = sdev->host;
845 struct scsi_request *sreq;
847 scsi_device_unbusy(sdev);
850 * Clear the flags which say that the device/host is no longer
851 * capable of accepting new commands. These are set in scsi_queue.c
852 * for both the queue full condition on a device, and for a
853 * host full condition on the host.
855 * XXX(hch): What about locking?
857 shost->host_blocked = 0;
858 sdev->device_blocked = 0;
861 * If we have valid sense information, then some kind of recovery
862 * must have taken place. Make a note of this.
864 if (SCSI_SENSE_VALID(cmd))
865 cmd->result |= (DRIVER_SENSE << 24);
867 SCSI_LOG_MLCOMPLETE(4, printk("Notifying upper driver of completion "
868 "for device %d %x\n", sdev->id, cmd->result));
870 cmd->owner = SCSI_OWNER_HIGHLEVEL;
871 cmd->state = SCSI_STATE_FINISHED;
874 * We can get here with use_sg=0, causing a panic in the upper level
876 cmd->use_sg = cmd->old_use_sg;
879 * If there is an associated request structure, copy the data over
880 * before we call the completion function.
882 sreq = cmd->sc_request;
884 sreq->sr_result = sreq->sr_command->result;
885 if (sreq->sr_result) {
886 memcpy(sreq->sr_sense_buffer,
887 sreq->sr_command->sense_buffer,
888 sizeof(sreq->sr_sense_buffer));
894 EXPORT_SYMBOL(scsi_finish_command);
897 * Function: scsi_adjust_queue_depth()
899 * Purpose: Allow low level drivers to tell us to change the queue depth
900 * on a specific SCSI device
902 * Arguments: sdev - SCSI Device in question
903 * tagged - Do we use tagged queueing (non-0) or do we treat
904 * this device as an untagged device (0)
905 * tags - Number of tags allowed if tagged queueing enabled,
906 * or number of commands the low level driver can
907 * queue up in non-tagged mode (as per cmd_per_lun).
911 * Lock Status: None held on entry
913 * Notes: Low level drivers may call this at any time and we will do
914 * the right thing depending on whether or not the device is
915 * currently active and whether or not it even has the
916 * command blocks built yet.
918 * XXX(hch): What exactly is device_request_lock trying to protect?
920 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
922 static spinlock_t device_request_lock = SPIN_LOCK_UNLOCKED;
926 * refuse to set tagged depth to an unworkable size
931 spin_lock_irqsave(&device_request_lock, flags);
932 spin_lock(sdev->request_queue->queue_lock);
934 /* Check to see if the queue is managed by the block layer
935 * if it is, and we fail to adjust the depth, exit */
936 if (blk_queue_tagged(sdev->request_queue) &&
937 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
940 sdev->queue_depth = tags;
942 case MSG_ORDERED_TAG:
943 sdev->ordered_tags = 1;
944 sdev->simple_tags = 1;
947 sdev->ordered_tags = 0;
948 sdev->simple_tags = 1;
951 printk(KERN_WARNING "(scsi%d:%d:%d:%d) "
952 "scsi_adjust_queue_depth, bad queue type, "
953 "disabled\n", sdev->host->host_no,
954 sdev->channel, sdev->id, sdev->lun);
956 sdev->ordered_tags = sdev->simple_tags = 0;
957 sdev->queue_depth = tags;
961 spin_unlock(sdev->request_queue->queue_lock);
962 spin_unlock_irqrestore(&device_request_lock, flags);
966 * Function: scsi_track_queue_full()
968 * Purpose: This function will track successive QUEUE_FULL events on a
969 * specific SCSI device to determine if and when there is a
970 * need to adjust the queue depth on the device.
972 * Arguments: sdev - SCSI Device in question
973 * depth - Current number of outstanding SCSI commands on
974 * this device, not counting the one returned as
977 * Returns: 0 - No change needed
978 * >0 - Adjust queue depth to this new depth
979 * -1 - Drop back to untagged operation using host->cmd_per_lun
980 * as the untagged command depth
982 * Lock Status: None held on entry
984 * Notes: Low level drivers may call this at any time and we will do
985 * "The Right Thing." We are interrupt context safe.
987 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
989 if ((jiffies >> 4) == sdev->last_queue_full_time)
992 sdev->last_queue_full_time = (jiffies >> 4);
993 if (sdev->last_queue_full_depth != depth) {
994 sdev->last_queue_full_count = 1;
995 sdev->last_queue_full_depth = depth;
997 sdev->last_queue_full_count++;
1000 if (sdev->last_queue_full_count <= 10)
1002 if (sdev->last_queue_full_depth < 8) {
1003 /* Drop back to untagged */
1004 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
1008 if (sdev->ordered_tags)
1009 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
1011 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
1016 * scsi_device_get - get an addition reference to a scsi_device
1017 * @sdev: device to get a reference to
1019 * Gets a reference to the scsi_device and increments the use count
1020 * of the underlying LLDD module. You must hold host_lock of the
1021 * parent Scsi_Host or already have a reference when calling this.
1023 int scsi_device_get(struct scsi_device *sdev)
1025 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
1027 if (!get_device(&sdev->sdev_gendev))
1029 if (!try_module_get(sdev->host->hostt->module)) {
1030 put_device(&sdev->sdev_gendev);
1035 EXPORT_SYMBOL(scsi_device_get);
1038 * scsi_device_put - release a reference to a scsi_device
1039 * @sdev: device to release a reference on.
1041 * Release a reference to the scsi_device and decrements the use count
1042 * of the underlying LLDD module. The device is freed once the last
1045 void scsi_device_put(struct scsi_device *sdev)
1047 module_put(sdev->host->hostt->module);
1048 put_device(&sdev->sdev_gendev);
1050 EXPORT_SYMBOL(scsi_device_put);
1052 /* helper for shost_for_each_device, thus not documented */
1053 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1054 struct scsi_device *prev)
1056 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1057 struct scsi_device *next = NULL;
1058 unsigned long flags;
1060 spin_lock_irqsave(shost->host_lock, flags);
1061 while (list->next != &shost->__devices) {
1062 next = list_entry(list->next, struct scsi_device, siblings);
1063 /* skip devices that we can't get a reference to */
1064 if (!scsi_device_get(next))
1069 spin_unlock_irqrestore(shost->host_lock, flags);
1072 scsi_device_put(prev);
1075 EXPORT_SYMBOL(__scsi_iterate_devices);
1078 * scsi_device_lookup - find a device given the host (UNLOCKED)
1079 * @shost: SCSI host pointer
1080 * @channel: SCSI channel (zero if only one channel)
1081 * @pun: SCSI target number (physical unit number)
1082 * @lun: SCSI Logical Unit Number
1084 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1085 * give host. The returned scsi_device does not have an additional reference.
1086 * You must hold the host's host_lock over this call and any access to the
1087 * returned scsi_device.
1089 * Note: The only reason why drivers would want to use this is because
1090 * they're need to access the device list in irq context. Otherwise you
1091 * really want to use scsi_device_lookup instead.
1093 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1094 uint channel, uint id, uint lun)
1096 struct scsi_device *sdev;
1098 list_for_each_entry(sdev, &shost->__devices, siblings) {
1099 if (sdev->channel == channel && sdev->id == id &&
1106 EXPORT_SYMBOL(__scsi_device_lookup);
1109 * scsi_device_lookup - find a device given the host
1110 * @shost: SCSI host pointer
1111 * @channel: SCSI channel (zero if only one channel)
1112 * @id: SCSI target number (physical unit number)
1113 * @lun: SCSI Logical Unit Number
1115 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1116 * give host. The returned scsi_device has an additional reference that
1117 * needs to be release with scsi_host_put once you're done with it.
1119 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1120 uint channel, uint id, uint lun)
1122 struct scsi_device *sdev;
1123 unsigned long flags;
1125 spin_lock_irqsave(shost->host_lock, flags);
1126 sdev = __scsi_device_lookup(shost, channel, id, lun);
1127 if (sdev && scsi_device_get(sdev))
1129 spin_unlock_irqrestore(shost->host_lock, flags);
1133 EXPORT_SYMBOL(scsi_device_lookup);
1136 * scsi_device_cancel - cancel outstanding IO to this device
1137 * @sdev: Pointer to struct scsi_device
1138 * @recovery: Boolean instructing function to recover device or not.
1141 int scsi_device_cancel(struct scsi_device *sdev, int recovery)
1143 struct scsi_cmnd *scmd;
1144 LIST_HEAD(active_list);
1145 struct list_head *lh, *lh_sf;
1146 unsigned long flags;
1148 scsi_device_set_state(sdev, SDEV_CANCEL);
1150 spin_lock_irqsave(&sdev->list_lock, flags);
1151 list_for_each_entry(scmd, &sdev->cmd_list, list) {
1152 if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) {
1154 * If we are unable to remove the timer, it means
1155 * that the command has already timed out or
1158 if (!scsi_delete_timer(scmd))
1160 list_add_tail(&scmd->eh_entry, &active_list);
1163 spin_unlock_irqrestore(&sdev->list_lock, flags);
1165 if (!list_empty(&active_list)) {
1166 list_for_each_safe(lh, lh_sf, &active_list) {
1167 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1170 scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
1172 scmd->result = (DID_ABORT << 16);
1173 scsi_finish_command(scmd);
1181 #ifdef CONFIG_HOTPLUG_CPU
1182 static int scsi_cpu_notify(struct notifier_block *self,
1183 unsigned long action, void *hcpu)
1185 int cpu = (unsigned long)hcpu;
1189 /* Drain scsi_done_q. */
1190 local_irq_disable();
1191 list_splice_init(&per_cpu(scsi_done_q, cpu),
1192 &__get_cpu_var(scsi_done_q));
1193 raise_softirq_irqoff(SCSI_SOFTIRQ);
1202 static struct notifier_block __devinitdata scsi_cpu_nb = {
1203 .notifier_call = scsi_cpu_notify,
1206 #define register_scsi_cpu() register_cpu_notifier(&scsi_cpu_nb)
1207 #define unregister_scsi_cpu() unregister_cpu_notifier(&scsi_cpu_nb)
1209 #define register_scsi_cpu()
1210 #define unregister_scsi_cpu()
1211 #endif /* CONFIG_HOTPLUG_CPU */
1213 MODULE_DESCRIPTION("SCSI core");
1214 MODULE_LICENSE("GPL");
1216 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1217 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1219 static int __init init_scsi(void)
1223 error = scsi_init_queue();
1226 error = scsi_init_procfs();
1229 error = scsi_init_devinfo();
1231 goto cleanup_procfs;
1232 error = scsi_init_hosts();
1234 goto cleanup_devlist;
1235 error = scsi_init_sysctl();
1238 error = scsi_sysfs_register();
1240 goto cleanup_sysctl;
1242 for (i = 0; i < NR_CPUS; i++)
1243 INIT_LIST_HEAD(&per_cpu(scsi_done_q, i));
1245 devfs_mk_dir("scsi");
1246 open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL);
1247 register_scsi_cpu();
1248 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1256 scsi_exit_devinfo();
1261 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1266 static void __exit exit_scsi(void)
1268 scsi_sysfs_unregister();
1271 scsi_exit_devinfo();
1272 devfs_remove("scsi");
1275 unregister_scsi_cpu();
1278 subsys_initcall(init_scsi);
1279 module_exit(exit_scsi);