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 00000000000..2e7ab3ab099
--- /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);