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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/scsi/scsi.c
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Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/scsi/scsi.c')
-rw-r--r--drivers/scsi/scsi.c1375
1 files changed, 1375 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
new file mode 100644
index 000000000000..2e7ab3ab0993
--- /dev/null
+++ b/drivers/scsi/scsi.c
@@ -0,0 +1,1375 @@
+/*
+ * scsi.c Copyright (C) 1992 Drew Eckhardt
+ * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
+ * Copyright (C) 2002, 2003 Christoph Hellwig
+ *
+ * generic mid-level SCSI driver
+ * Initial versions: Drew Eckhardt
+ * Subsequent revisions: Eric Youngdale
+ *
+ * <drew@colorado.edu>
+ *
+ * Bug correction thanks go to :
+ * Rik Faith <faith@cs.unc.edu>
+ * Tommy Thorn <tthorn>
+ * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
+ *
+ * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
+ * add scatter-gather, multiple outstanding request, and other
+ * enhancements.
+ *
+ * Native multichannel, wide scsi, /proc/scsi and hot plugging
+ * support added by Michael Neuffer <mike@i-connect.net>
+ *
+ * Added request_module("scsi_hostadapter") for kerneld:
+ * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
+ * Bjorn Ekwall <bj0rn@blox.se>
+ * (changed to kmod)
+ *
+ * Major improvements to the timeout, abort, and reset processing,
+ * as well as performance modifications for large queue depths by
+ * Leonard N. Zubkoff <lnz@dandelion.com>
+ *
+ * Converted cli() code to spinlocks, Ingo Molnar
+ *
+ * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
+ *
+ * out_of_space hacks, D. Gilbert (dpg) 990608
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/unistd.h>
+#include <linux/spinlock.h>
+#include <linux/kmod.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/cpu.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_tcq.h>
+#include <scsi/scsi_request.h>
+
+#include "scsi_priv.h"
+#include "scsi_logging.h"
+
+
+/*
+ * Definitions and constants.
+ */
+
+#define MIN_RESET_DELAY (2*HZ)
+
+/* Do not call reset on error if we just did a reset within 15 sec. */
+#define MIN_RESET_PERIOD (15*HZ)
+
+/*
+ * Macro to determine the size of SCSI command. This macro takes vendor
+ * unique commands into account. SCSI commands in groups 6 and 7 are
+ * vendor unique and we will depend upon the command length being
+ * supplied correctly in cmd_len.
+ */
+#define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
+ COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
+
+/*
+ * Note - the initial logging level can be set here to log events at boot time.
+ * After the system is up, you may enable logging via the /proc interface.
+ */
+unsigned int scsi_logging_level;
+#if defined(CONFIG_SCSI_LOGGING)
+EXPORT_SYMBOL(scsi_logging_level);
+#endif
+
+const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] = {
+ "Direct-Access ",
+ "Sequential-Access",
+ "Printer ",
+ "Processor ",
+ "WORM ",
+ "CD-ROM ",
+ "Scanner ",
+ "Optical Device ",
+ "Medium Changer ",
+ "Communications ",
+ "Unknown ",
+ "Unknown ",
+ "RAID ",
+ "Enclosure ",
+};
+EXPORT_SYMBOL(scsi_device_types);
+
+/*
+ * Function: scsi_allocate_request
+ *
+ * Purpose: Allocate a request descriptor.
+ *
+ * Arguments: device - device for which we want a request
+ * gfp_mask - allocation flags passed to kmalloc
+ *
+ * Lock status: No locks assumed to be held. This function is SMP-safe.
+ *
+ * Returns: Pointer to request block.
+ */
+struct scsi_request *scsi_allocate_request(struct scsi_device *sdev,
+ int gfp_mask)
+{
+ const int offset = ALIGN(sizeof(struct scsi_request), 4);
+ const int size = offset + sizeof(struct request);
+ struct scsi_request *sreq;
+
+ sreq = kmalloc(size, gfp_mask);
+ if (likely(sreq != NULL)) {
+ memset(sreq, 0, size);
+ sreq->sr_request = (struct request *)(((char *)sreq) + offset);
+ sreq->sr_device = sdev;
+ sreq->sr_host = sdev->host;
+ sreq->sr_magic = SCSI_REQ_MAGIC;
+ sreq->sr_data_direction = DMA_BIDIRECTIONAL;
+ }
+
+ return sreq;
+}
+EXPORT_SYMBOL(scsi_allocate_request);
+
+void __scsi_release_request(struct scsi_request *sreq)
+{
+ struct request *req = sreq->sr_request;
+
+ /* unlikely because the tag was usually ended earlier by the
+ * mid-layer. However, for layering reasons ULD's don't end
+ * the tag of commands they generate. */
+ if (unlikely(blk_rq_tagged(req))) {
+ unsigned long flags;
+ struct request_queue *q = req->q;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_queue_end_tag(q, req);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
+
+
+ if (likely(sreq->sr_command != NULL)) {
+ struct scsi_cmnd *cmd = sreq->sr_command;
+
+ sreq->sr_command = NULL;
+ scsi_next_command(cmd);
+ }
+}
+
+/*
+ * Function: scsi_release_request
+ *
+ * Purpose: Release a request descriptor.
+ *
+ * Arguments: sreq - request to release
+ *
+ * Lock status: No locks assumed to be held. This function is SMP-safe.
+ */
+void scsi_release_request(struct scsi_request *sreq)
+{
+ __scsi_release_request(sreq);
+ kfree(sreq);
+}
+EXPORT_SYMBOL(scsi_release_request);
+
+struct scsi_host_cmd_pool {
+ kmem_cache_t *slab;
+ unsigned int users;
+ char *name;
+ unsigned int slab_flags;
+ unsigned int gfp_mask;
+};
+
+static struct scsi_host_cmd_pool scsi_cmd_pool = {
+ .name = "scsi_cmd_cache",
+ .slab_flags = SLAB_HWCACHE_ALIGN,
+};
+
+static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
+ .name = "scsi_cmd_cache(DMA)",
+ .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
+ .gfp_mask = __GFP_DMA,
+};
+
+static DECLARE_MUTEX(host_cmd_pool_mutex);
+
+static struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost,
+ int gfp_mask)
+{
+ struct scsi_cmnd *cmd;
+
+ cmd = kmem_cache_alloc(shost->cmd_pool->slab,
+ gfp_mask | shost->cmd_pool->gfp_mask);
+
+ if (unlikely(!cmd)) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&shost->free_list_lock, flags);
+ if (likely(!list_empty(&shost->free_list))) {
+ cmd = list_entry(shost->free_list.next,
+ struct scsi_cmnd, list);
+ list_del_init(&cmd->list);
+ }
+ spin_unlock_irqrestore(&shost->free_list_lock, flags);
+ }
+
+ return cmd;
+}
+
+/*
+ * Function: scsi_get_command()
+ *
+ * Purpose: Allocate and setup a scsi command block
+ *
+ * Arguments: dev - parent scsi device
+ * gfp_mask- allocator flags
+ *
+ * Returns: The allocated scsi command structure.
+ */
+struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, int gfp_mask)
+{
+ struct scsi_cmnd *cmd;
+
+ /* Bail if we can't get a reference to the device */
+ if (!get_device(&dev->sdev_gendev))
+ return NULL;
+
+ cmd = __scsi_get_command(dev->host, gfp_mask);
+
+ if (likely(cmd != NULL)) {
+ unsigned long flags;
+
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->device = dev;
+ cmd->state = SCSI_STATE_UNUSED;
+ cmd->owner = SCSI_OWNER_NOBODY;
+ init_timer(&cmd->eh_timeout);
+ INIT_LIST_HEAD(&cmd->list);
+ spin_lock_irqsave(&dev->list_lock, flags);
+ list_add_tail(&cmd->list, &dev->cmd_list);
+ spin_unlock_irqrestore(&dev->list_lock, flags);
+ } else
+ put_device(&dev->sdev_gendev);
+
+ return cmd;
+}
+EXPORT_SYMBOL(scsi_get_command);
+
+/*
+ * Function: scsi_put_command()
+ *
+ * Purpose: Free a scsi command block
+ *
+ * Arguments: cmd - command block to free
+ *
+ * Returns: Nothing.
+ *
+ * Notes: The command must not belong to any lists.
+ */
+void scsi_put_command(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ /* serious error if the command hasn't come from a device list */
+ spin_lock_irqsave(&cmd->device->list_lock, flags);
+ BUG_ON(list_empty(&cmd->list));
+ list_del_init(&cmd->list);
+ spin_unlock(&cmd->device->list_lock);
+ /* changing locks here, don't need to restore the irq state */
+ spin_lock(&shost->free_list_lock);
+ if (unlikely(list_empty(&shost->free_list))) {
+ list_add(&cmd->list, &shost->free_list);
+ cmd = NULL;
+ }
+ spin_unlock_irqrestore(&shost->free_list_lock, flags);
+
+ if (likely(cmd != NULL))
+ kmem_cache_free(shost->cmd_pool->slab, cmd);
+
+ put_device(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL(scsi_put_command);
+
+/*
+ * Function: scsi_setup_command_freelist()
+ *
+ * Purpose: Setup the command freelist for a scsi host.
+ *
+ * Arguments: shost - host to allocate the freelist for.
+ *
+ * Returns: Nothing.
+ */
+int scsi_setup_command_freelist(struct Scsi_Host *shost)
+{
+ struct scsi_host_cmd_pool *pool;
+ struct scsi_cmnd *cmd;
+
+ spin_lock_init(&shost->free_list_lock);
+ INIT_LIST_HEAD(&shost->free_list);
+
+ /*
+ * Select a command slab for this host and create it if not
+ * yet existant.
+ */
+ down(&host_cmd_pool_mutex);
+ pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
+ if (!pool->users) {
+ pool->slab = kmem_cache_create(pool->name,
+ sizeof(struct scsi_cmnd), 0,
+ pool->slab_flags, NULL, NULL);
+ if (!pool->slab)
+ goto fail;
+ }
+
+ pool->users++;
+ shost->cmd_pool = pool;
+ up(&host_cmd_pool_mutex);
+
+ /*
+ * Get one backup command for this host.
+ */
+ cmd = kmem_cache_alloc(shost->cmd_pool->slab,
+ GFP_KERNEL | shost->cmd_pool->gfp_mask);
+ if (!cmd)
+ goto fail2;
+ list_add(&cmd->list, &shost->free_list);
+ return 0;
+
+ fail2:
+ if (!--pool->users)
+ kmem_cache_destroy(pool->slab);
+ return -ENOMEM;
+ fail:
+ up(&host_cmd_pool_mutex);
+ return -ENOMEM;
+
+}
+
+/*
+ * Function: scsi_destroy_command_freelist()
+ *
+ * Purpose: Release the command freelist for a scsi host.
+ *
+ * Arguments: shost - host that's freelist is going to be destroyed
+ */
+void scsi_destroy_command_freelist(struct Scsi_Host *shost)
+{
+ while (!list_empty(&shost->free_list)) {
+ struct scsi_cmnd *cmd;
+
+ cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
+ list_del_init(&cmd->list);
+ kmem_cache_free(shost->cmd_pool->slab, cmd);
+ }
+
+ down(&host_cmd_pool_mutex);
+ if (!--shost->cmd_pool->users)
+ kmem_cache_destroy(shost->cmd_pool->slab);
+ up(&host_cmd_pool_mutex);
+}
+
+#ifdef CONFIG_SCSI_LOGGING
+void scsi_log_send(struct scsi_cmnd *cmd)
+{
+ unsigned int level;
+ struct scsi_device *sdev;
+
+ /*
+ * If ML QUEUE log level is greater than or equal to:
+ *
+ * 1: nothing (match completion)
+ *
+ * 2: log opcode + command of all commands
+ *
+ * 3: same as 2 plus dump cmd address
+ *
+ * 4: same as 3 plus dump extra junk
+ */
+ if (unlikely(scsi_logging_level)) {
+ level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
+ SCSI_LOG_MLQUEUE_BITS);
+ if (level > 1) {
+ sdev = cmd->device;
+ printk(KERN_INFO "scsi <%d:%d:%d:%d> send ",
+ sdev->host->host_no, sdev->channel, sdev->id,
+ sdev->lun);
+ if (level > 2)
+ printk("0x%p ", cmd);
+ /*
+ * spaces to match disposition and cmd->result
+ * output in scsi_log_completion.
+ */
+ printk(" ");
+ scsi_print_command(cmd);
+ if (level > 3) {
+ printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
+ " done = 0x%p, queuecommand 0x%p\n",
+ cmd->buffer, cmd->bufflen,
+ cmd->done,
+ sdev->host->hostt->queuecommand);
+
+ }
+ }
+ }
+}
+
+void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
+{
+ unsigned int level;
+ struct scsi_device *sdev;
+
+ /*
+ * If ML COMPLETE log level is greater than or equal to:
+ *
+ * 1: log disposition, result, opcode + command, and conditionally
+ * sense data for failures or non SUCCESS dispositions.
+ *
+ * 2: same as 1 but for all command completions.
+ *
+ * 3: same as 2 plus dump cmd address
+ *
+ * 4: same as 3 plus dump extra junk
+ */
+ if (unlikely(scsi_logging_level)) {
+ level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
+ SCSI_LOG_MLCOMPLETE_BITS);
+ if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
+ (level > 1)) {
+ sdev = cmd->device;
+ printk(KERN_INFO "scsi <%d:%d:%d:%d> done ",
+ sdev->host->host_no, sdev->channel, sdev->id,
+ sdev->lun);
+ if (level > 2)
+ printk("0x%p ", cmd);
+ /*
+ * Dump truncated values, so we usually fit within
+ * 80 chars.
+ */
+ switch (disposition) {
+ case SUCCESS:
+ printk("SUCCESS");
+ break;
+ case NEEDS_RETRY:
+ printk("RETRY ");
+ break;
+ case ADD_TO_MLQUEUE:
+ printk("MLQUEUE");
+ break;
+ case FAILED:
+ printk("FAILED ");
+ break;
+ case TIMEOUT_ERROR:
+ /*
+ * If called via scsi_times_out.
+ */
+ printk("TIMEOUT");
+ break;
+ default:
+ printk("UNKNOWN");
+ }
+ printk(" %8x ", cmd->result);
+ scsi_print_command(cmd);
+ if (status_byte(cmd->result) & CHECK_CONDITION) {
+ /*
+ * XXX The print_sense formatting/prefix
+ * doesn't match this function.
+ */
+ scsi_print_sense("", cmd);
+ }
+ if (level > 3) {
+ printk(KERN_INFO "scsi host busy %d failed %d\n",
+ sdev->host->host_busy,
+ sdev->host->host_failed);
+ }
+ }
+ }
+}
+#endif
+
+/*
+ * Assign a serial number and pid to the request for error recovery
+ * and debugging purposes. Protected by the Host_Lock of host.
+ */
+static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
+{
+ cmd->serial_number = host->cmd_serial_number++;
+ if (cmd->serial_number == 0)
+ cmd->serial_number = host->cmd_serial_number++;
+
+ cmd->pid = host->cmd_pid++;
+ if (cmd->pid == 0)
+ cmd->pid = host->cmd_pid++;
+}
+
+/*
+ * Function: scsi_dispatch_command
+ *
+ * Purpose: Dispatch a command to the low-level driver.
+ *
+ * Arguments: cmd - command block we are dispatching.
+ *
+ * Notes:
+ */
+int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
+{
+ struct Scsi_Host *host = cmd->device->host;
+ unsigned long flags = 0;
+ unsigned long timeout;
+ int rtn = 0;
+
+ /* check if the device is still usable */
+ if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
+ /* in SDEV_DEL we error all commands. DID_NO_CONNECT
+ * returns an immediate error upwards, and signals
+ * that the device is no longer present */
+ cmd->result = DID_NO_CONNECT << 16;
+ atomic_inc(&cmd->device->iorequest_cnt);
+ scsi_done(cmd);
+ /* return 0 (because the command has been processed) */
+ goto out;
+ }
+
+ /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
+ if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
+ /*
+ * in SDEV_BLOCK, the command is just put back on the device
+ * queue. The suspend state has already blocked the queue so
+ * future requests should not occur until the device
+ * transitions out of the suspend state.
+ */
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
+
+ SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
+
+ /*
+ * NOTE: rtn is still zero here because we don't need the
+ * queue to be plugged on return (it's already stopped)
+ */
+ goto out;
+ }
+
+ /*
+ * If SCSI-2 or lower, store the LUN value in cmnd.
+ */
+ if (cmd->device->scsi_level <= SCSI_2) {
+ cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
+ (cmd->device->lun << 5 & 0xe0);
+ }
+
+ /*
+ * We will wait MIN_RESET_DELAY clock ticks after the last reset so
+ * we can avoid the drive not being ready.
+ */
+ timeout = host->last_reset + MIN_RESET_DELAY;
+
+ if (host->resetting && time_before(jiffies, timeout)) {
+ int ticks_remaining = timeout - jiffies;
+ /*
+ * NOTE: This may be executed from within an interrupt
+ * handler! This is bad, but for now, it'll do. The irq
+ * level of the interrupt handler has been masked out by the
+ * platform dependent interrupt handling code already, so the
+ * sti() here will not cause another call to the SCSI host's
+ * interrupt handler (assuming there is one irq-level per
+ * host).
+ */
+ while (--ticks_remaining >= 0)
+ mdelay(1 + 999 / HZ);
+ host->resetting = 0;
+ }
+
+ /*
+ * AK: unlikely race here: for some reason the timer could
+ * expire before the serial number is set up below.
+ */
+ scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
+
+ scsi_log_send(cmd);
+
+ /*
+ * We will use a queued command if possible, otherwise we will
+ * emulate the queuing and calling of completion function ourselves.
+ */
+
+ cmd->state = SCSI_STATE_QUEUED;
+ cmd->owner = SCSI_OWNER_LOWLEVEL;
+
+ atomic_inc(&cmd->device->iorequest_cnt);
+
+ /*
+ * Before we queue this command, check if the command
+ * length exceeds what the host adapter can handle.
+ */
+ if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
+ SCSI_LOG_MLQUEUE(3,
+ printk("queuecommand : command too long.\n"));
+ cmd->result = (DID_ABORT << 16);
+
+ scsi_done(cmd);
+ goto out;
+ }
+
+ spin_lock_irqsave(host->host_lock, flags);
+ scsi_cmd_get_serial(host, cmd);
+
+ if (unlikely(test_bit(SHOST_CANCEL, &host->shost_state))) {
+ cmd->result = (DID_NO_CONNECT << 16);
+ scsi_done(cmd);
+ } else {
+ rtn = host->hostt->queuecommand(cmd, scsi_done);
+ }
+ spin_unlock_irqrestore(host->host_lock, flags);
+ if (rtn) {
+ atomic_inc(&cmd->device->iodone_cnt);
+ scsi_queue_insert(cmd,
+ (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
+ rtn : SCSI_MLQUEUE_HOST_BUSY);
+ SCSI_LOG_MLQUEUE(3,
+ printk("queuecommand : request rejected\n"));
+ }
+
+ out:
+ SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
+ return rtn;
+}
+
+/*
+ * Function: scsi_init_cmd_from_req
+ *
+ * Purpose: Queue a SCSI command
+ * Purpose: Initialize a struct scsi_cmnd from a struct scsi_request
+ *
+ * Arguments: cmd - command descriptor.
+ * sreq - Request from the queue.
+ *
+ * Lock status: None needed.
+ *
+ * Returns: Nothing.
+ *
+ * Notes: Mainly transfer data from the request structure to the
+ * command structure. The request structure is allocated
+ * using the normal memory allocator, and requests can pile
+ * up to more or less any depth. The command structure represents
+ * a consumable resource, as these are allocated into a pool
+ * when the SCSI subsystem initializes. The preallocation is
+ * required so that in low-memory situations a disk I/O request
+ * won't cause the memory manager to try and write out a page.
+ * The request structure is generally used by ioctls and character
+ * devices.
+ */
+void scsi_init_cmd_from_req(struct scsi_cmnd *cmd, struct scsi_request *sreq)
+{
+ sreq->sr_command = cmd;
+
+ cmd->owner = SCSI_OWNER_MIDLEVEL;
+ cmd->cmd_len = sreq->sr_cmd_len;
+ cmd->use_sg = sreq->sr_use_sg;
+
+ cmd->request = sreq->sr_request;
+ memcpy(cmd->data_cmnd, sreq->sr_cmnd, sizeof(cmd->data_cmnd));
+ cmd->serial_number = 0;
+ cmd->serial_number_at_timeout = 0;
+ cmd->bufflen = sreq->sr_bufflen;
+ cmd->buffer = sreq->sr_buffer;
+ cmd->retries = 0;
+ cmd->allowed = sreq->sr_allowed;
+ cmd->done = sreq->sr_done;
+ cmd->timeout_per_command = sreq->sr_timeout_per_command;
+ cmd->sc_data_direction = sreq->sr_data_direction;
+ cmd->sglist_len = sreq->sr_sglist_len;
+ cmd->underflow = sreq->sr_underflow;
+ cmd->sc_request = sreq;
+ memcpy(cmd->cmnd, sreq->sr_cmnd, sizeof(sreq->sr_cmnd));
+
+ /*
+ * Zero the sense buffer. Some host adapters automatically request
+ * sense on error. 0 is not a valid sense code.
+ */
+ memset(cmd->sense_buffer, 0, sizeof(sreq->sr_sense_buffer));
+ cmd->request_buffer = sreq->sr_buffer;
+ cmd->request_bufflen = sreq->sr_bufflen;
+ cmd->old_use_sg = cmd->use_sg;
+ if (cmd->cmd_len == 0)
+ cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
+ cmd->old_cmd_len = cmd->cmd_len;
+ cmd->sc_old_data_direction = cmd->sc_data_direction;
+ cmd->old_underflow = cmd->underflow;
+
+ /*
+ * Start the timer ticking.
+ */
+ cmd->internal_timeout = NORMAL_TIMEOUT;
+ cmd->abort_reason = 0;
+ cmd->result = 0;
+
+ SCSI_LOG_MLQUEUE(3, printk("Leaving scsi_init_cmd_from_req()\n"));
+}
+
+/*
+ * Per-CPU I/O completion queue.
+ */
+static DEFINE_PER_CPU(struct list_head, scsi_done_q);
+
+/**
+ * scsi_done - Enqueue the finished SCSI command into the done queue.
+ * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
+ * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
+ *
+ * This function is the mid-level's (SCSI Core) interrupt routine, which
+ * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
+ * the command to the done queue for further processing.
+ *
+ * This is the producer of the done queue who enqueues at the tail.
+ *
+ * This function is interrupt context safe.
+ */
+void scsi_done(struct scsi_cmnd *cmd)
+{
+ /*
+ * We don't have to worry about this one timing out any more.
+ * If we are unable to remove the timer, then the command
+ * has already timed out. In which case, we have no choice but to
+ * let the timeout function run, as we have no idea where in fact
+ * that function could really be. It might be on another processor,
+ * etc, etc.
+ */
+ if (!scsi_delete_timer(cmd))
+ return;
+ __scsi_done(cmd);
+}
+
+/* Private entry to scsi_done() to complete a command when the timer
+ * isn't running --- used by scsi_times_out */
+void __scsi_done(struct scsi_cmnd *cmd)
+{
+ unsigned long flags;
+
+ /*
+ * Set the serial numbers back to zero
+ */
+ cmd->serial_number = 0;
+ cmd->serial_number_at_timeout = 0;
+ cmd->state = SCSI_STATE_BHQUEUE;
+ cmd->owner = SCSI_OWNER_BH_HANDLER;
+
+ atomic_inc(&cmd->device->iodone_cnt);
+ if (cmd->result)
+ atomic_inc(&cmd->device->ioerr_cnt);
+
+ /*
+ * Next, enqueue the command into the done queue.
+ * It is a per-CPU queue, so we just disable local interrupts
+ * and need no spinlock.
+ */
+ local_irq_save(flags);
+ list_add_tail(&cmd->eh_entry, &__get_cpu_var(scsi_done_q));
+ raise_softirq_irqoff(SCSI_SOFTIRQ);
+ local_irq_restore(flags);
+}
+
+/**
+ * scsi_softirq - Perform post-interrupt processing of finished SCSI commands.
+ *
+ * This is the consumer of the done queue.
+ *
+ * This is called with all interrupts enabled. This should reduce
+ * interrupt latency, stack depth, and reentrancy of the low-level
+ * drivers.
+ */
+static void scsi_softirq(struct softirq_action *h)
+{
+ int disposition;
+ LIST_HEAD(local_q);
+
+ local_irq_disable();
+ list_splice_init(&__get_cpu_var(scsi_done_q), &local_q);
+ local_irq_enable();
+
+ while (!list_empty(&local_q)) {
+ struct scsi_cmnd *cmd = list_entry(local_q.next,
+ struct scsi_cmnd, eh_entry);
+ list_del_init(&cmd->eh_entry);
+
+ disposition = scsi_decide_disposition(cmd);
+ scsi_log_completion(cmd, disposition);
+ switch (disposition) {
+ case SUCCESS:
+ scsi_finish_command(cmd);
+ break;
+ case NEEDS_RETRY:
+ scsi_retry_command(cmd);
+ break;
+ case ADD_TO_MLQUEUE:
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
+ break;
+ default:
+ if (!scsi_eh_scmd_add(cmd, 0))
+ scsi_finish_command(cmd);
+ }
+ }
+}
+
+/*
+ * Function: scsi_retry_command
+ *
+ * Purpose: Send a command back to the low level to be retried.
+ *
+ * Notes: This command is always executed in the context of the
+ * bottom half handler, or the error handler thread. Low
+ * level drivers should not become re-entrant as a result of
+ * this.
+ */
+int scsi_retry_command(struct scsi_cmnd *cmd)
+{
+ /*
+ * Restore the SCSI command state.
+ */
+ scsi_setup_cmd_retry(cmd);
+
+ /*
+ * Zero the sense information from the last time we tried
+ * this command.
+ */
+ memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
+
+ return scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
+}
+
+/*
+ * Function: scsi_finish_command
+ *
+ * Purpose: Pass command off to upper layer for finishing of I/O
+ * request, waking processes that are waiting on results,
+ * etc.
+ */
+void scsi_finish_command(struct scsi_cmnd *cmd)
+{
+ struct scsi_device *sdev = cmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ struct scsi_request *sreq;
+
+ scsi_device_unbusy(sdev);
+
+ /*
+ * Clear the flags which say that the device/host is no longer
+ * capable of accepting new commands. These are set in scsi_queue.c
+ * for both the queue full condition on a device, and for a
+ * host full condition on the host.
+ *
+ * XXX(hch): What about locking?
+ */
+ shost->host_blocked = 0;
+ sdev->device_blocked = 0;
+
+ /*
+ * If we have valid sense information, then some kind of recovery
+ * must have taken place. Make a note of this.
+ */
+ if (SCSI_SENSE_VALID(cmd))
+ cmd->result |= (DRIVER_SENSE << 24);
+
+ SCSI_LOG_MLCOMPLETE(4, printk("Notifying upper driver of completion "
+ "for device %d %x\n", sdev->id, cmd->result));
+
+ cmd->owner = SCSI_OWNER_HIGHLEVEL;
+ cmd->state = SCSI_STATE_FINISHED;
+
+ /*
+ * We can get here with use_sg=0, causing a panic in the upper level
+ */
+ cmd->use_sg = cmd->old_use_sg;
+
+ /*
+ * If there is an associated request structure, copy the data over
+ * before we call the completion function.
+ */
+ sreq = cmd->sc_request;
+ if (sreq) {
+ sreq->sr_result = sreq->sr_command->result;
+ if (sreq->sr_result) {
+ memcpy(sreq->sr_sense_buffer,
+ sreq->sr_command->sense_buffer,
+ sizeof(sreq->sr_sense_buffer));
+ }
+ }
+
+ cmd->done(cmd);
+}
+EXPORT_SYMBOL(scsi_finish_command);
+
+/*
+ * Function: scsi_adjust_queue_depth()
+ *
+ * Purpose: Allow low level drivers to tell us to change the queue depth
+ * on a specific SCSI device
+ *
+ * Arguments: sdev - SCSI Device in question
+ * tagged - Do we use tagged queueing (non-0) or do we treat
+ * this device as an untagged device (0)
+ * tags - Number of tags allowed if tagged queueing enabled,
+ * or number of commands the low level driver can
+ * queue up in non-tagged mode (as per cmd_per_lun).
+ *
+ * Returns: Nothing
+ *
+ * Lock Status: None held on entry
+ *
+ * Notes: Low level drivers may call this at any time and we will do
+ * the right thing depending on whether or not the device is
+ * currently active and whether or not it even has the
+ * command blocks built yet.
+ */
+void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
+{
+ unsigned long flags;
+
+ /*
+ * refuse to set tagged depth to an unworkable size
+ */
+ if (tags <= 0)
+ return;
+
+ spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
+
+ /* Check to see if the queue is managed by the block layer
+ * if it is, and we fail to adjust the depth, exit */
+ if (blk_queue_tagged(sdev->request_queue) &&
+ blk_queue_resize_tags(sdev->request_queue, tags) != 0)
+ goto out;
+
+ sdev->queue_depth = tags;
+ switch (tagged) {
+ case MSG_ORDERED_TAG:
+ sdev->ordered_tags = 1;
+ sdev->simple_tags = 1;
+ break;
+ case MSG_SIMPLE_TAG:
+ sdev->ordered_tags = 0;
+ sdev->simple_tags = 1;
+ break;
+ default:
+ printk(KERN_WARNING "(scsi%d:%d:%d:%d) "
+ "scsi_adjust_queue_depth, bad queue type, "
+ "disabled\n", sdev->host->host_no,
+ sdev->channel, sdev->id, sdev->lun);
+ case 0:
+ sdev->ordered_tags = sdev->simple_tags = 0;
+ sdev->queue_depth = tags;
+ break;
+ }
+ out:
+ spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+}
+EXPORT_SYMBOL(scsi_adjust_queue_depth);
+
+/*
+ * Function: scsi_track_queue_full()
+ *
+ * Purpose: This function will track successive QUEUE_FULL events on a
+ * specific SCSI device to determine if and when there is a
+ * need to adjust the queue depth on the device.
+ *
+ * Arguments: sdev - SCSI Device in question
+ * depth - Current number of outstanding SCSI commands on
+ * this device, not counting the one returned as
+ * QUEUE_FULL.
+ *
+ * Returns: 0 - No change needed
+ * >0 - Adjust queue depth to this new depth
+ * -1 - Drop back to untagged operation using host->cmd_per_lun
+ * as the untagged command depth
+ *
+ * Lock Status: None held on entry
+ *
+ * Notes: Low level drivers may call this at any time and we will do
+ * "The Right Thing." We are interrupt context safe.
+ */
+int scsi_track_queue_full(struct scsi_device *sdev, int depth)
+{
+ if ((jiffies >> 4) == sdev->last_queue_full_time)
+ return 0;
+
+ sdev->last_queue_full_time = (jiffies >> 4);
+ if (sdev->last_queue_full_depth != depth) {
+ sdev->last_queue_full_count = 1;
+ sdev->last_queue_full_depth = depth;
+ } else {
+ sdev->last_queue_full_count++;
+ }
+
+ if (sdev->last_queue_full_count <= 10)
+ return 0;
+ if (sdev->last_queue_full_depth < 8) {
+ /* Drop back to untagged */
+ scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
+ return -1;
+ }
+
+ if (sdev->ordered_tags)
+ scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
+ else
+ scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
+ return depth;
+}
+EXPORT_SYMBOL(scsi_track_queue_full);
+
+/**
+ * scsi_device_get - get an addition reference to a scsi_device
+ * @sdev: device to get a reference to
+ *
+ * Gets a reference to the scsi_device and increments the use count
+ * of the underlying LLDD module. You must hold host_lock of the
+ * parent Scsi_Host or already have a reference when calling this.
+ */
+int scsi_device_get(struct scsi_device *sdev)
+{
+ if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
+ return -ENXIO;
+ if (!get_device(&sdev->sdev_gendev))
+ return -ENXIO;
+ if (!try_module_get(sdev->host->hostt->module)) {
+ put_device(&sdev->sdev_gendev);
+ return -ENXIO;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(scsi_device_get);
+
+/**
+ * scsi_device_put - release a reference to a scsi_device
+ * @sdev: device to release a reference on.
+ *
+ * Release a reference to the scsi_device and decrements the use count
+ * of the underlying LLDD module. The device is freed once the last
+ * user vanishes.
+ */
+void scsi_device_put(struct scsi_device *sdev)
+{
+ module_put(sdev->host->hostt->module);
+ put_device(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL(scsi_device_put);
+
+/* helper for shost_for_each_device, thus not documented */
+struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
+ struct scsi_device *prev)
+{
+ struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
+ struct scsi_device *next = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ while (list->next != &shost->__devices) {
+ next = list_entry(list->next, struct scsi_device, siblings);
+ /* skip devices that we can't get a reference to */
+ if (!scsi_device_get(next))
+ break;
+ next = NULL;
+ list = list->next;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ if (prev)
+ scsi_device_put(prev);
+ return next;
+}
+EXPORT_SYMBOL(__scsi_iterate_devices);
+
+/**
+ * starget_for_each_device - helper to walk all devices of a target
+ * @starget: target whose devices we want to iterate over.
+ *
+ * This traverses over each devices of @shost. The devices have
+ * a reference that must be released by scsi_host_put when breaking
+ * out of the loop.
+ */
+void starget_for_each_device(struct scsi_target *starget, void * data,
+ void (*fn)(struct scsi_device *, void *))
+{
+ struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
+ struct scsi_device *sdev;
+
+ shost_for_each_device(sdev, shost) {
+ if ((sdev->channel == starget->channel) &&
+ (sdev->id == starget->id))
+ fn(sdev, data);
+ }
+}
+EXPORT_SYMBOL(starget_for_each_device);
+
+/**
+ * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
+ * @starget: SCSI target pointer
+ * @lun: SCSI Logical Unit Number
+ *
+ * Looks up the scsi_device with the specified @lun for a give
+ * @starget. The returned scsi_device does not have an additional
+ * reference. You must hold the host's host_lock over this call and
+ * any access to the returned scsi_device.
+ *
+ * Note: The only reason why drivers would want to use this is because
+ * they're need to access the device list in irq context. Otherwise you
+ * really want to use scsi_device_lookup_by_target instead.
+ **/
+struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
+ uint lun)
+{
+ struct scsi_device *sdev;
+
+ list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
+ if (sdev->lun ==lun)
+ return sdev;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(__scsi_device_lookup_by_target);
+
+/**
+ * scsi_device_lookup_by_target - find a device given the target
+ * @starget: SCSI target pointer
+ * @lun: SCSI Logical Unit Number
+ *
+ * Looks up the scsi_device with the specified @channel, @id, @lun for a
+ * give host. The returned scsi_device has an additional reference that
+ * needs to be release with scsi_host_put once you're done with it.
+ **/
+struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
+ uint lun)
+{
+ struct scsi_device *sdev;
+ struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ sdev = __scsi_device_lookup_by_target(starget, lun);
+ if (sdev && scsi_device_get(sdev))
+ sdev = NULL;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ return sdev;
+}
+EXPORT_SYMBOL(scsi_device_lookup_by_target);
+
+/**
+ * scsi_device_lookup - find a device given the host (UNLOCKED)
+ * @shost: SCSI host pointer
+ * @channel: SCSI channel (zero if only one channel)
+ * @pun: SCSI target number (physical unit number)
+ * @lun: SCSI Logical Unit Number
+ *
+ * Looks up the scsi_device with the specified @channel, @id, @lun for a
+ * give host. The returned scsi_device does not have an additional reference.
+ * You must hold the host's host_lock over this call and any access to the
+ * returned scsi_device.
+ *
+ * Note: The only reason why drivers would want to use this is because
+ * they're need to access the device list in irq context. Otherwise you
+ * really want to use scsi_device_lookup instead.
+ **/
+struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
+ uint channel, uint id, uint lun)
+{
+ struct scsi_device *sdev;
+
+ list_for_each_entry(sdev, &shost->__devices, siblings) {
+ if (sdev->channel == channel && sdev->id == id &&
+ sdev->lun ==lun)
+ return sdev;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL(__scsi_device_lookup);
+
+/**
+ * scsi_device_lookup - find a device given the host
+ * @shost: SCSI host pointer
+ * @channel: SCSI channel (zero if only one channel)
+ * @id: SCSI target number (physical unit number)
+ * @lun: SCSI Logical Unit Number
+ *
+ * Looks up the scsi_device with the specified @channel, @id, @lun for a
+ * give host. The returned scsi_device has an additional reference that
+ * needs to be release with scsi_host_put once you're done with it.
+ **/
+struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
+ uint channel, uint id, uint lun)
+{
+ struct scsi_device *sdev;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ sdev = __scsi_device_lookup(shost, channel, id, lun);
+ if (sdev && scsi_device_get(sdev))
+ sdev = NULL;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ return sdev;
+}
+EXPORT_SYMBOL(scsi_device_lookup);
+
+/**
+ * scsi_device_cancel - cancel outstanding IO to this device
+ * @sdev: Pointer to struct scsi_device
+ * @recovery: Boolean instructing function to recover device or not.
+ *
+ **/
+int scsi_device_cancel(struct scsi_device *sdev, int recovery)
+{
+ struct scsi_cmnd *scmd;
+ LIST_HEAD(active_list);
+ struct list_head *lh, *lh_sf;
+ unsigned long flags;
+
+ scsi_device_set_state(sdev, SDEV_CANCEL);
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_for_each_entry(scmd, &sdev->cmd_list, list) {
+ if (scmd->request && scmd->request->rq_status != RQ_INACTIVE) {
+ /*
+ * If we are unable to remove the timer, it means
+ * that the command has already timed out or
+ * finished.
+ */
+ if (!scsi_delete_timer(scmd))
+ continue;
+ list_add_tail(&scmd->eh_entry, &active_list);
+ }
+ }
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+
+ if (!list_empty(&active_list)) {
+ list_for_each_safe(lh, lh_sf, &active_list) {
+ scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
+ list_del_init(lh);
+ if (recovery) {
+ scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD);
+ } else {
+ scmd->result = (DID_ABORT << 16);
+ scsi_finish_command(scmd);
+ }
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(scsi_device_cancel);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int scsi_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ int cpu = (unsigned long)hcpu;
+
+ switch(action) {
+ case CPU_DEAD:
+ /* Drain scsi_done_q. */
+ local_irq_disable();
+ list_splice_init(&per_cpu(scsi_done_q, cpu),
+ &__get_cpu_var(scsi_done_q));
+ raise_softirq_irqoff(SCSI_SOFTIRQ);
+ local_irq_enable();
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __devinitdata scsi_cpu_nb = {
+ .notifier_call = scsi_cpu_notify,
+};
+
+#define register_scsi_cpu() register_cpu_notifier(&scsi_cpu_nb)
+#define unregister_scsi_cpu() unregister_cpu_notifier(&scsi_cpu_nb)
+#else
+#define register_scsi_cpu()
+#define unregister_scsi_cpu()
+#endif /* CONFIG_HOTPLUG_CPU */
+
+MODULE_DESCRIPTION("SCSI core");
+MODULE_LICENSE("GPL");
+
+module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
+
+static int __init init_scsi(void)
+{
+ int error, i;
+
+ error = scsi_init_queue();
+ if (error)
+ return error;
+ error = scsi_init_procfs();
+ if (error)
+ goto cleanup_queue;
+ error = scsi_init_devinfo();
+ if (error)
+ goto cleanup_procfs;
+ error = scsi_init_hosts();
+ if (error)
+ goto cleanup_devlist;
+ error = scsi_init_sysctl();
+ if (error)
+ goto cleanup_hosts;
+ error = scsi_sysfs_register();
+ if (error)
+ goto cleanup_sysctl;
+
+ for (i = 0; i < NR_CPUS; i++)
+ INIT_LIST_HEAD(&per_cpu(scsi_done_q, i));
+
+ devfs_mk_dir("scsi");
+ open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL);
+ register_scsi_cpu();
+ printk(KERN_NOTICE "SCSI subsystem initialized\n");
+ return 0;
+
+cleanup_sysctl:
+ scsi_exit_sysctl();
+cleanup_hosts:
+ scsi_exit_hosts();
+cleanup_devlist:
+ scsi_exit_devinfo();
+cleanup_procfs:
+ scsi_exit_procfs();
+cleanup_queue:
+ scsi_exit_queue();
+ printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
+ -error);
+ return error;
+}
+
+static void __exit exit_scsi(void)
+{
+ scsi_sysfs_unregister();
+ scsi_exit_sysctl();
+ scsi_exit_hosts();
+ scsi_exit_devinfo();
+ devfs_remove("scsi");
+ scsi_exit_procfs();
+ scsi_exit_queue();
+ unregister_scsi_cpu();
+}
+
+subsys_initcall(init_scsi);
+module_exit(exit_scsi);