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!

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);