[SCSI] lpfc 8.3.25: Adapter Interface fixes and changes
[linux-2.6.git] / drivers / scsi / scsi.c
index f33e2eb..2aeb2e9 100644 (file)
@@ -40,7 +40,6 @@
 #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>
@@ -60,6 +59,7 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_tcq.h>
@@ -67,6 +67,9 @@
 #include "scsi_priv.h"
 #include "scsi_logging.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/scsi.h>
+
 static void scsi_done(struct scsi_cmnd *cmd);
 
 /*
@@ -79,15 +82,6 @@ static void scsi_done(struct scsi_cmnd *cmd);
 #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.
  */
@@ -122,6 +116,11 @@ static const char *const scsi_device_types[] = {
        "Automation/Drive ",
 };
 
+/**
+ * scsi_device_type - Return 17 char string indicating device type.
+ * @type: type number to look up
+ */
+
 const char * scsi_device_type(unsigned type)
 {
        if (type == 0x1e)
@@ -136,32 +135,116 @@ const char * scsi_device_type(unsigned type)
 EXPORT_SYMBOL(scsi_device_type);
 
 struct scsi_host_cmd_pool {
-       struct kmem_cache       *slab;
-       unsigned int    users;
-       char            *name;
-       unsigned int    slab_flags;
-       gfp_t           gfp_mask;
+       struct kmem_cache       *cmd_slab;
+       struct kmem_cache       *sense_slab;
+       unsigned int            users;
+       char                    *cmd_name;
+       char                    *sense_name;
+       unsigned int            slab_flags;
+       gfp_t                   gfp_mask;
 };
 
 static struct scsi_host_cmd_pool scsi_cmd_pool = {
-       .name           = "scsi_cmd_cache",
+       .cmd_name       = "scsi_cmd_cache",
+       .sense_name     = "scsi_sense_cache",
        .slab_flags     = SLAB_HWCACHE_ALIGN,
 };
 
 static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
-       .name           = "scsi_cmd_cache(DMA)",
+       .cmd_name       = "scsi_cmd_cache(DMA)",
+       .sense_name     = "scsi_sense_cache(DMA)",
        .slab_flags     = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
        .gfp_mask       = __GFP_DMA,
 };
 
 static DEFINE_MUTEX(host_cmd_pool_mutex);
 
-struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
+/**
+ * scsi_pool_alloc_command - internal function to get a fully allocated command
+ * @pool:      slab pool to allocate the command from
+ * @gfp_mask:  mask for the allocation
+ *
+ * Returns a fully allocated command (with the allied sense buffer) or
+ * NULL on failure
+ */
+static struct scsi_cmnd *
+scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
 {
        struct scsi_cmnd *cmd;
 
-       cmd = kmem_cache_alloc(shost->cmd_pool->slab,
-                       gfp_mask | shost->cmd_pool->gfp_mask);
+       cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
+       if (!cmd)
+               return NULL;
+
+       cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
+                                            gfp_mask | pool->gfp_mask);
+       if (!cmd->sense_buffer) {
+               kmem_cache_free(pool->cmd_slab, cmd);
+               return NULL;
+       }
+
+       return cmd;
+}
+
+/**
+ * scsi_pool_free_command - internal function to release a command
+ * @pool:      slab pool to allocate the command from
+ * @cmd:       command to release
+ *
+ * the command must previously have been allocated by
+ * scsi_pool_alloc_command.
+ */
+static void
+scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
+                        struct scsi_cmnd *cmd)
+{
+       if (cmd->prot_sdb)
+               kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
+
+       kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
+       kmem_cache_free(pool->cmd_slab, cmd);
+}
+
+/**
+ * scsi_host_alloc_command - internal function to allocate command
+ * @shost:     SCSI host whose pool to allocate from
+ * @gfp_mask:  mask for the allocation
+ *
+ * Returns a fully allocated command with sense buffer and protection
+ * data buffer (where applicable) or NULL on failure
+ */
+static struct scsi_cmnd *
+scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
+{
+       struct scsi_cmnd *cmd;
+
+       cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+       if (!cmd)
+               return NULL;
+
+       if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
+               cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
+
+               if (!cmd->prot_sdb) {
+                       scsi_pool_free_command(shost->cmd_pool, cmd);
+                       return NULL;
+               }
+       }
+
+       return cmd;
+}
+
+/**
+ * __scsi_get_command - Allocate a struct scsi_cmnd
+ * @shost: host to transmit command
+ * @gfp_mask: allocation mask
+ *
+ * Description: allocate a struct scsi_cmd from host's slab, recycling from the
+ *              host's free_list if necessary.
+ */
+struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
+{
+       struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
 
        if (unlikely(!cmd)) {
                unsigned long flags;
@@ -173,19 +256,28 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
                        list_del_init(&cmd->list);
                }
                spin_unlock_irqrestore(&shost->free_list_lock, flags);
+
+               if (cmd) {
+                       void *buf, *prot;
+
+                       buf = cmd->sense_buffer;
+                       prot = cmd->prot_sdb;
+
+                       memset(cmd, 0, sizeof(*cmd));
+
+                       cmd->sense_buffer = buf;
+                       cmd->prot_sdb = prot;
+               }
        }
 
        return cmd;
 }
 EXPORT_SYMBOL_GPL(__scsi_get_command);
 
-/*
- * Function:   scsi_get_command()
- *
- * Purpose:    Allocate and setup a scsi command block
- *
- * Arguments:  dev     - parent scsi device
- *             gfp_mask- allocator flags
+/**
+ * scsi_get_command - Allocate and setup a scsi command block
+ * @dev: parent scsi device
+ * @gfp_mask: allocator flags
  *
  * Returns:    The allocated scsi command structure.
  */
@@ -202,9 +294,7 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
        if (likely(cmd != NULL)) {
                unsigned long flags;
 
-               memset(cmd, 0, sizeof(*cmd));
                cmd->device = dev;
-               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);
@@ -217,6 +307,12 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
 }
 EXPORT_SYMBOL(scsi_get_command);
 
+/**
+ * __scsi_put_command - Free a struct scsi_cmnd
+ * @shost: dev->host
+ * @cmd: Command to free
+ * @dev: parent scsi device
+ */
 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
                        struct device *dev)
 {
@@ -231,18 +327,15 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
        spin_unlock_irqrestore(&shost->free_list_lock, flags);
 
        if (likely(cmd != NULL))
-               kmem_cache_free(shost->cmd_pool->slab, cmd);
+               scsi_pool_free_command(shost->cmd_pool, cmd);
 
        put_device(dev);
 }
 EXPORT_SYMBOL(__scsi_put_command);
 
-/*
- * Function:   scsi_put_command()
- *
- * Purpose:    Free a scsi command block
- *
- * Arguments:  cmd     - command block to free
+/**
+ * scsi_put_command - Free a scsi command block
+ * @cmd: command block to free
  *
  * Returns:    Nothing.
  *
@@ -263,89 +356,180 @@ void scsi_put_command(struct scsi_cmnd *cmd)
 }
 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)
+static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
 {
-       struct scsi_host_cmd_pool *pool;
-       struct scsi_cmnd *cmd;
-
-       spin_lock_init(&shost->free_list_lock);
-       INIT_LIST_HEAD(&shost->free_list);
-
+       struct scsi_host_cmd_pool *retval = NULL, *pool;
        /*
         * Select a command slab for this host and create it if not
-        * yet existant.
+        * yet existent.
         */
        mutex_lock(&host_cmd_pool_mutex);
-       pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
+       pool = (gfp_mask & __GFP_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)
+               pool->cmd_slab = kmem_cache_create(pool->cmd_name,
+                                                  sizeof(struct scsi_cmnd), 0,
+                                                  pool->slab_flags, NULL);
+               if (!pool->cmd_slab)
+                       goto fail;
+
+               pool->sense_slab = kmem_cache_create(pool->sense_name,
+                                                    SCSI_SENSE_BUFFERSIZE, 0,
+                                                    pool->slab_flags, NULL);
+               if (!pool->sense_slab) {
+                       kmem_cache_destroy(pool->cmd_slab);
                        goto fail;
+               }
        }
 
        pool->users++;
-       shost->cmd_pool = pool;
+       retval = pool;
+ fail:
        mutex_unlock(&host_cmd_pool_mutex);
+       return retval;
+}
+
+static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
+{
+       struct scsi_host_cmd_pool *pool;
 
+       mutex_lock(&host_cmd_pool_mutex);
+       pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
+               &scsi_cmd_pool;
        /*
-        * Get one backup command for this host.
+        * This may happen if a driver has a mismatched get and put
+        * of the command pool; the driver should be implicated in
+        * the stack trace
         */
-       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;
+       BUG_ON(pool->users == 0);
 
- fail2:
-       if (!--pool->users)
-               kmem_cache_destroy(pool->slab);
-       return -ENOMEM;
- fail:
+       if (!--pool->users) {
+               kmem_cache_destroy(pool->cmd_slab);
+               kmem_cache_destroy(pool->sense_slab);
+       }
        mutex_unlock(&host_cmd_pool_mutex);
-       return -ENOMEM;
+}
 
+/**
+ * scsi_allocate_command - get a fully allocated SCSI command
+ * @gfp_mask:  allocation mask
+ *
+ * This function is for use outside of the normal host based pools.
+ * It allocates the relevant command and takes an additional reference
+ * on the pool it used.  This function *must* be paired with
+ * scsi_free_command which also has the identical mask, otherwise the
+ * free pool counts will eventually go wrong and you'll trigger a bug.
+ *
+ * This function should *only* be used by drivers that need a static
+ * command allocation at start of day for internal functions.
+ */
+struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
+{
+       struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
+
+       if (!pool)
+               return NULL;
+
+       return scsi_pool_alloc_command(pool, gfp_mask);
 }
+EXPORT_SYMBOL(scsi_allocate_command);
 
-/*
- * Function:   scsi_destroy_command_freelist()
+/**
+ * scsi_free_command - free a command allocated by scsi_allocate_command
+ * @gfp_mask:  mask used in the original allocation
+ * @cmd:       command to free
+ *
+ * Note: using the original allocation mask is vital because that's
+ * what determines which command pool we use to free the command.  Any
+ * mismatch will cause the system to BUG eventually.
+ */
+void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
+{
+       struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
+
+       /*
+        * this could trigger if the mask to scsi_allocate_command
+        * doesn't match this mask.  Otherwise we're guaranteed that this
+        * succeeds because scsi_allocate_command must have taken a reference
+        * on the pool
+        */
+       BUG_ON(!pool);
+
+       scsi_pool_free_command(pool, cmd);
+       /*
+        * scsi_put_host_cmd_pool is called twice; once to release the
+        * reference we took above, and once to release the reference
+        * originally taken by scsi_allocate_command
+        */
+       scsi_put_host_cmd_pool(gfp_mask);
+       scsi_put_host_cmd_pool(gfp_mask);
+}
+EXPORT_SYMBOL(scsi_free_command);
+
+/**
+ * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
+ * @shost: host to allocate the freelist for.
  *
- * Purpose:    Release the command freelist for a scsi host.
+ * Description: The command freelist protects against system-wide out of memory
+ * deadlock by preallocating one SCSI command structure for each host, so the
+ * system can always write to a swap file on a device associated with that host.
  *
- * Arguments:  shost   - host that's freelist is going to be destroyed
+ * Returns:    Nothing.
+ */
+int scsi_setup_command_freelist(struct Scsi_Host *shost)
+{
+       struct scsi_cmnd *cmd;
+       const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
+
+       spin_lock_init(&shost->free_list_lock);
+       INIT_LIST_HEAD(&shost->free_list);
+
+       shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
+
+       if (!shost->cmd_pool)
+               return -ENOMEM;
+
+       /*
+        * Get one backup command for this host.
+        */
+       cmd = scsi_host_alloc_command(shost, gfp_mask);
+       if (!cmd) {
+               scsi_put_host_cmd_pool(gfp_mask);
+               shost->cmd_pool = NULL;
+               return -ENOMEM;
+       }
+       list_add(&cmd->list, &shost->free_list);
+       return 0;
+}
+
+/**
+ * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
+ * @shost: host whose freelist is going to be destroyed
  */
 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
 {
+       /*
+        * If cmd_pool is NULL the free list was not initialized, so
+        * do not attempt to release resources.
+        */
+       if (!shost->cmd_pool)
+               return;
+
        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);
+               scsi_pool_free_command(shost->cmd_pool, cmd);
        }
-
-       mutex_lock(&host_cmd_pool_mutex);
-       if (!--shost->cmd_pool->users)
-               kmem_cache_destroy(shost->cmd_pool->slab);
-       mutex_unlock(&host_cmd_pool_mutex);
+       shost->cmd_pool = NULL;
+       scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
 }
 
 #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:
@@ -362,22 +546,16 @@ void scsi_log_send(struct scsi_cmnd *cmd)
                level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
                                       SCSI_LOG_MLQUEUE_BITS);
                if (level > 1) {
-                       sdev = cmd->device;
-                       sdev_printk(KERN_INFO, sdev, "send ");
+                       scmd_printk(KERN_INFO, cmd, "Send: ");
                        if (level > 2)
                                printk("0x%p ", cmd);
-                       /*
-                        * spaces to match disposition and cmd->result
-                        * output in scsi_log_completion.
-                        */
-                       printk("                 ");
+                       printk("\n");
                        scsi_print_command(cmd);
                        if (level > 3) {
                                printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
-                                      " done = 0x%p, queuecommand 0x%p\n",
-                                       cmd->request_buffer, cmd->request_bufflen,
-                                       cmd->done,
-                                       sdev->host->hostt->queuecommand);
+                                      " queuecommand 0x%p\n",
+                                       scsi_sglist(cmd), scsi_bufflen(cmd),
+                                       cmd->device->host->hostt->queuecommand);
 
                        }
                }
@@ -387,7 +565,6 @@ void scsi_log_send(struct scsi_cmnd *cmd)
 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:
@@ -406,8 +583,7 @@ void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
                                       SCSI_LOG_MLCOMPLETE_BITS);
                if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
                    (level > 1)) {
-                       sdev = cmd->device;
-                       sdev_printk(KERN_INFO, sdev, "done ");
+                       scmd_printk(KERN_INFO, cmd, "Done: ");
                        if (level > 2)
                                printk("0x%p ", cmd);
                        /*
@@ -416,96 +592,92 @@ void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
                         */
                        switch (disposition) {
                        case SUCCESS:
-                               printk("SUCCESS");
+                               printk("SUCCESS\n");
                                break;
                        case NEEDS_RETRY:
-                               printk("RETRY  ");
+                               printk("RETRY\n");
                                break;
                        case ADD_TO_MLQUEUE:
-                               printk("MLQUEUE");
+                               printk("MLQUEUE\n");
                                break;
                        case FAILED:
-                               printk("FAILED ");
+                               printk("FAILED\n");
                                break;
                        case TIMEOUT_ERROR:
                                /* 
                                 * If called via scsi_times_out.
                                 */
-                               printk("TIMEOUT");
+                               printk("TIMEOUT\n");
                                break;
                        default:
-                               printk("UNKNOWN");
+                               printk("UNKNOWN\n");
                        }
-                       printk(" %8x ", cmd->result);
+                       scsi_print_result(cmd);
                        scsi_print_command(cmd);
-                       if (status_byte(cmd->result) & CHECK_CONDITION) {
-                               /*
-                                * XXX The scsi_print_sense formatting/prefix
-                                * doesn't match this function.
-                                */
+                       if (status_byte(cmd->result) & CHECK_CONDITION)
                                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);
-                       }
+                       if (level > 3)
+                               scmd_printk(KERN_INFO, cmd,
+                                           "scsi host busy %d failed %d\n",
+                                           cmd->device->host->host_busy,
+                                           cmd->device->host->host_failed);
                }
        }
 }
 #endif
 
-/* 
- * Assign a serial number and pid to the request for error recovery
+/**
+ * scsi_cmd_get_serial - Assign a serial number to a command
+ * @host: the scsi host
+ * @cmd: command to assign serial number to
+ *
+ * Description: a serial number identifies a 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)
+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++;
 }
+EXPORT_SYMBOL(scsi_cmd_get_serial);
 
-/*
- * Function:    scsi_dispatch_command
- *
- * Purpose:     Dispatch a command to the low-level driver.
- *
- * Arguments:   cmd - command block we are dispatching.
+/**
+ * scsi_dispatch_command - Dispatch a command to the low-level driver.
+ * @cmd: command block we are dispatching.
  *
- * Notes:
+ * Return: nonzero return request was rejected and device's queue needs to be
+ * plugged.
  */
 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;
 
+       atomic_inc(&cmd->device->iorequest_cnt);
+
        /* 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);
+               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)) {
+       /* Check to see if the scsi lld made this device blocked. */
+       if (unlikely(scsi_device_blocked(cmd->device))) {
                /* 
-                * 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.
+                * in blocked state, 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"));
@@ -548,50 +720,40 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
                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.
-        */
-       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) {
+       if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
                SCSI_LOG_MLQUEUE(3,
-                               printk("queuecommand : command too long.\n"));
+                       printk("queuecommand : command too long. "
+                              "cdb_size=%d host->max_cmd_len=%d\n",
+                              cmd->cmd_len, cmd->device->host->max_cmd_len));
                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(host->shost_state == SHOST_DEL)) {
                cmd->result = (DID_NO_CONNECT << 16);
                scsi_done(cmd);
        } else {
-               rtn = host->hostt->queuecommand(cmd, scsi_done);
+               trace_scsi_dispatch_cmd_start(cmd);
+               cmd->scsi_done = scsi_done;
+               rtn = host->hostt->queuecommand(host, cmd);
        }
-       spin_unlock_irqrestore(host->host_lock, flags);
+
        if (rtn) {
-               if (scsi_delete_timer(cmd)) {
-                       atomic_inc(&cmd->device->iodone_cnt);
-                       scsi_queue_insert(cmd,
-                                         (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
-                                         rtn : SCSI_MLQUEUE_HOST_BUSY);
-               }
+               trace_scsi_dispatch_cmd_error(cmd, rtn);
+               if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
+                   rtn != SCSI_MLQUEUE_TARGET_BUSY)
+                       rtn = SCSI_MLQUEUE_HOST_BUSY;
+
+               scsi_queue_insert(cmd, rtn);
+
                SCSI_LOG_MLQUEUE(3,
                    printk("queuecommand : request rejected\n"));
        }
@@ -602,31 +764,13 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 }
 
 /**
- * scsi_req_abort_cmd -- Request command recovery for the specified command
- * cmd: pointer to the SCSI command of interest
- *
- * This function requests that SCSI Core start recovery for the
- * command by deleting the timer and adding the command to the eh
- * queue.  It can be called by either LLDDs or SCSI Core.  LLDDs who
- * implement their own error recovery MAY ignore the timeout event if
- * they generated scsi_req_abort_cmd.
- */
-void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
-{
-       if (!scsi_delete_timer(cmd))
-               return;
-       scsi_times_out(cmd);
-}
-EXPORT_SYMBOL(scsi_req_abort_cmd);
-
-/**
  * 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.
+ * Description: 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.
  *
@@ -634,55 +778,31 @@ EXPORT_SYMBOL(scsi_req_abort_cmd);
  */
 static 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);
+       trace_scsi_dispatch_cmd_done(cmd);
+       blk_complete_request(cmd->request);
 }
 
-/* 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)
+/* Move this to a header if it becomes more generally useful */
+static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
 {
-       struct request *rq = cmd->request;
-
-       /*
-        * Set the serial numbers back to zero
-        */
-       cmd->serial_number = 0;
-
-       atomic_inc(&cmd->device->iodone_cnt);
-       if (cmd->result)
-               atomic_inc(&cmd->device->ioerr_cnt);
-
-       BUG_ON(!rq);
-
-       /*
-        * The uptodate/nbytes values don't matter, as we allow partial
-        * completes and thus will check this in the softirq callback
-        */
-       rq->completion_data = cmd;
-       blk_complete_request(rq);
+       return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
 }
 
-/*
- * Function:    scsi_finish_command
+/**
+ * scsi_finish_command - cleanup and pass command back to upper layer
+ * @cmd: the command
  *
- * Purpose:     Pass command off to upper layer for finishing of I/O
+ * Description: 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_target *starget = scsi_target(sdev);
        struct Scsi_Host *shost = sdev->host;
+       struct scsi_driver *drv;
+       unsigned int good_bytes;
 
        scsi_device_unbusy(sdev);
 
@@ -695,6 +815,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
         * XXX(hch): What about locking?
          */
         shost->host_blocked = 0;
+       starget->target_blocked = 0;
         sdev->device_blocked = 0;
 
        /*
@@ -708,22 +829,33 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
                                "Notifying upper driver of completion "
                                "(result %x)\n", cmd->result));
 
-       cmd->done(cmd);
+       good_bytes = scsi_bufflen(cmd);
+        if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
+               int old_good_bytes = good_bytes;
+               drv = scsi_cmd_to_driver(cmd);
+               if (drv->done)
+                       good_bytes = drv->done(cmd);
+               /*
+                * USB may not give sense identifying bad sector and
+                * simply return a residue instead, so subtract off the
+                * residue if drv->done() error processing indicates no
+                * change to the completion length.
+                */
+               if (good_bytes == old_good_bytes)
+                       good_bytes -= scsi_get_resid(cmd);
+       }
+       scsi_io_completion(cmd, good_bytes);
 }
 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).
+/**
+ * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
+ * @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
  *
@@ -746,11 +878,20 @@ void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
 
        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;
+       /*
+        * Check to see if the queue is managed by the block layer.
+        * If it is, and we fail to adjust the depth, exit.
+        *
+        * Do not resize the tag map if it is a host wide share bqt,
+        * because the size should be the hosts's can_queue. If there
+        * is more IO than the LLD's can_queue (so there are not enuogh
+        * tags) request_fn's host queue ready check will handle it.
+        */
+       if (!sdev->host->bqt) {
+               if (blk_queue_tagged(sdev->request_queue) &&
+                   blk_queue_resize_tags(sdev->request_queue, tags) != 0)
+                       goto out;
+       }
 
        sdev->queue_depth = tags;
        switch (tagged) {
@@ -776,20 +917,17 @@ void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
 }
 EXPORT_SYMBOL(scsi_adjust_queue_depth);
 
-/*
- * Function:   scsi_track_queue_full()
+/**
+ * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
+ * @sdev: SCSI Device in question
+ * @depth: Current number of outstanding SCSI commands on this device,
+ *         not counting the one returned as QUEUE_FULL.
  *
- * Purpose:    This function will track successive QUEUE_FULL events on a
+ * Description:        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
+ * 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
  *
@@ -800,10 +938,16 @@ EXPORT_SYMBOL(scsi_adjust_queue_depth);
  */
 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
 {
-       if ((jiffies >> 4) == sdev->last_queue_full_time)
+
+       /*
+        * Don't let QUEUE_FULLs on the same
+        * jiffies count, they could all be from
+        * same event.
+        */
+       if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
                return 0;
 
-       sdev->last_queue_full_time = (jiffies >> 4);
+       sdev->last_queue_full_time = jiffies;
        if (sdev->last_queue_full_depth != depth) {
                sdev->last_queue_full_count = 1;
                sdev->last_queue_full_depth = depth;
@@ -828,10 +972,101 @@ int scsi_track_queue_full(struct scsi_device *sdev, int depth)
 EXPORT_SYMBOL(scsi_track_queue_full);
 
 /**
- * scsi_device_get  -  get an addition reference to a scsi_device
+ * scsi_vpd_inquiry - Request a device provide us with a VPD page
+ * @sdev: The device to ask
+ * @buffer: Where to put the result
+ * @page: Which Vital Product Data to return
+ * @len: The length of the buffer
+ *
+ * This is an internal helper function.  You probably want to use
+ * scsi_get_vpd_page instead.
+ *
+ * Returns 0 on success or a negative error number.
+ */
+static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
+                                                       u8 page, unsigned len)
+{
+       int result;
+       unsigned char cmd[16];
+
+       cmd[0] = INQUIRY;
+       cmd[1] = 1;             /* EVPD */
+       cmd[2] = page;
+       cmd[3] = len >> 8;
+       cmd[4] = len & 0xff;
+       cmd[5] = 0;             /* Control byte */
+
+       /*
+        * I'm not convinced we need to try quite this hard to get VPD, but
+        * all the existing users tried this hard.
+        */
+       result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
+                                 len, NULL, 30 * HZ, 3, NULL);
+       if (result)
+               return result;
+
+       /* Sanity check that we got the page back that we asked for */
+       if (buffer[1] != page)
+               return -EIO;
+
+       return 0;
+}
+
+/**
+ * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
+ * @sdev: The device to ask
+ * @page: Which Vital Product Data to return
+ * @buf: where to store the VPD
+ * @buf_len: number of bytes in the VPD buffer area
+ *
+ * SCSI devices may optionally supply Vital Product Data.  Each 'page'
+ * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
+ * If the device supports this VPD page, this routine returns a pointer
+ * to a buffer containing the data from that page.  The caller is
+ * responsible for calling kfree() on this pointer when it is no longer
+ * needed.  If we cannot retrieve the VPD page this routine returns %NULL.
+ */
+int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
+                     int buf_len)
+{
+       int i, result;
+
+       /* Ask for all the pages supported by this device */
+       result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
+       if (result)
+               goto fail;
+
+       /* If the user actually wanted this page, we can skip the rest */
+       if (page == 0)
+               return 0;
+
+       for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
+               if (buf[i + 4] == page)
+                       goto found;
+
+       if (i < buf[3] && i >= buf_len - 4)
+               /* ran off the end of the buffer, give us benefit of doubt */
+               goto found;
+       /* The device claims it doesn't support the requested page */
+       goto fail;
+
+ found:
+       result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
+       if (result)
+               goto fail;
+
+       return 0;
+
+ fail:
+       return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
+
+/**
+ * scsi_device_get  -  get an additional reference to a scsi_device
  * @sdev:      device to get a reference to
  *
- * Gets a reference to the scsi_device and increments the use count
+ * Description: 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.
  */
@@ -853,8 +1088,8 @@ 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
+ * Description: 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)
@@ -871,7 +1106,7 @@ void scsi_device_put(struct scsi_device *sdev)
 }
 EXPORT_SYMBOL(scsi_device_put);
 
-/* helper for shost_for_each_device, thus not documented */
+/* helper for shost_for_each_device, see that for documentation */
 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
                                           struct scsi_device *prev)
 {
@@ -899,12 +1134,14 @@ 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.
+ * @data:      Opaque passed to each function call.
+ * @fn:                Function to call on each device
  *
- * This traverses over each devices of @shost.  The devices have
+ * This traverses over each device of @starget.  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 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);
@@ -919,17 +1156,46 @@ void starget_for_each_device(struct scsi_target *starget, void * data,
 EXPORT_SYMBOL(starget_for_each_device);
 
 /**
+ * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
+ * @starget:   target whose devices we want to iterate over.
+ * @data:      parameter for callback @fn()
+ * @fn:                callback function that is invoked for each device
+ *
+ * This traverses over each device of @starget.  It does _not_
+ * take a reference on the scsi_device, so the whole loop must be
+ * protected by shost->host_lock.
+ *
+ * Note:  The only reason why drivers would want to use this is because
+ * they need to access the device list in irq context.  Otherwise you
+ * really want to use starget_for_each_device instead.
+ **/
+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
+ * Description: Looks up the scsi_device with the specified @lun for a given
+ * @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.
+ * any access to the returned scsi_device. A scsi_device in state
+ * SDEV_DEL is skipped.
  *
- * 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
+ * Note:  The only reason why drivers should use this is because
+ * they 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,
@@ -938,6 +1204,8 @@ struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
        struct scsi_device *sdev;
 
        list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
+               if (sdev->sdev_state == SDEV_DEL)
+                       continue;
                if (sdev->lun ==lun)
                        return sdev;
        }
@@ -951,9 +1219,9 @@ EXPORT_SYMBOL(__scsi_device_lookup_by_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.
+ * Description: Looks up the scsi_device with the specified @lun for a given
+ * @starget.  The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
  **/
 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
                                                 uint lun)
@@ -973,19 +1241,19 @@ struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
 EXPORT_SYMBOL(scsi_device_lookup_by_target);
 
 /**
- * scsi_device_lookup - find a device given the host (UNLOCKED)
+ * __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)
+ * @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 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.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given 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
+ * they 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,
@@ -1010,9 +1278,9 @@ EXPORT_SYMBOL(__scsi_device_lookup);
  * @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.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host.  The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
  **/
 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
                uint channel, uint id, uint lun)
@@ -1030,52 +1298,6 @@ struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
 }
 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) {
-                       /*
-                        * 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)) {
-                               scmd->result = (DID_ABORT << 16);
-                               scsi_finish_command(scmd);
-                       }
-               }
-       }
-
-       return 0;
-}
-EXPORT_SYMBOL(scsi_device_cancel);
-
 MODULE_DESCRIPTION("SCSI core");
 MODULE_LICENSE("GPL");