1 files changed, 168 insertions, 114 deletions

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 0fb1709ce5e3..1a9fba6a9f92 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -122,6 +122,11 @@ 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 +141,45 @@ 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);
 
+/**
+ * __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;
+        unsigned char *buf;
 
-        cmd = kmem_cache_alloc(shost->cmd_pool->slab,
-                        gfp_mask | shost->cmd_pool->gfp_mask);
+        cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
+                               gfp_mask | shost->cmd_pool->gfp_mask);
 
         if (unlikely(!cmd)) {
                 unsigned long flags;
@@ -173,19 +191,32 @@ 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) {
+                        buf = cmd->sense_buffer;
+                        memset(cmd, 0, sizeof(*cmd));
+                        cmd->sense_buffer = buf;
+                }
+        } else {
+                buf = kmem_cache_alloc(shost->cmd_pool->sense_slab,
+                                       gfp_mask | shost->cmd_pool->gfp_mask);
+                if (likely(buf)) {
+                        memset(cmd, 0, sizeof(*cmd));
+                        cmd->sense_buffer = buf;
+                } else {
+                        kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
+                        cmd = NULL;
+                }
         }
 
         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.
  */
@@ -202,7 +233,6 @@ 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);
@@ -217,6 +247,12 @@ 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)
 {
@@ -230,19 +266,19 @@ 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);
+        if (likely(cmd != NULL)) {
+                kmem_cache_free(shost->cmd_pool->sense_slab,
+                                cmd->sense_buffer);
+                kmem_cache_free(shost->cmd_pool->cmd_slab, 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.
  *
@@ -263,12 +299,13 @@ 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.
+/**
+ * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
+ * @shost: host to allocate the freelist for.
  *
- * Arguments:   shost   - host to allocate the freelist for.
+ * 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.
  *
  * Returns:     Nothing.
  */
@@ -282,16 +319,24 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
 
         /*
          * 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);
         if (!pool->users) {
-                pool->slab = kmem_cache_create(pool->name,
-                                sizeof(struct scsi_cmnd), 0,
-                                pool->slab_flags, 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++;
@@ -301,29 +346,36 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
         /*
          * Get one backup command for this host.
          */
-        cmd = kmem_cache_alloc(shost->cmd_pool->slab,
-                        GFP_KERNEL | shost->cmd_pool->gfp_mask);
+        cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
+                               GFP_KERNEL | shost->cmd_pool->gfp_mask);
         if (!cmd)
                 goto fail2;
-        list_add(&cmd->list, &shost->free_list);                
+
+        cmd->sense_buffer = kmem_cache_alloc(shost->cmd_pool->sense_slab,
+                                             GFP_KERNEL |
+                                             shost->cmd_pool->gfp_mask);
+        if (!cmd->sense_buffer)
+                goto fail2;
+
+        list_add(&cmd->list, &shost->free_list);
         return 0;
 
  fail2:
-        if (!--pool->users)
-                kmem_cache_destroy(pool->slab);
-        return -ENOMEM;
+        if (cmd)
+                kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
+        mutex_lock(&host_cmd_pool_mutex);
+        if (!--pool->users) {
+                kmem_cache_destroy(pool->cmd_slab);
+                kmem_cache_destroy(pool->sense_slab);
+        }
  fail:
         mutex_unlock(&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
+/**
+ * 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)
 {
@@ -332,12 +384,16 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost)
 
                 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
                 list_del_init(&cmd->list);
-                kmem_cache_free(shost->cmd_pool->slab, cmd);
+                kmem_cache_free(shost->cmd_pool->sense_slab,
+                                cmd->sense_buffer);
+                kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
         }
 
         mutex_lock(&host_cmd_pool_mutex);
-        if (!--shost->cmd_pool->users)
-                kmem_cache_destroy(shost->cmd_pool->slab);
+        if (!--shost->cmd_pool->users) {
+                kmem_cache_destroy(shost->cmd_pool->cmd_slab);
+                kmem_cache_destroy(shost->cmd_pool->sense_slab);
+        }
         mutex_unlock(&host_cmd_pool_mutex);
 }
 
@@ -441,8 +497,12 @@ void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
 }
 #endif
 
-/* 
- * Assign a serial number 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)
@@ -452,14 +512,12 @@ static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd
                 cmd->serial_number = host->cmd_serial_number++;
 }
 
-/*
- * 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)
 {
@@ -585,7 +643,7 @@ 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
+ * @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
@@ -606,9 +664,9 @@ EXPORT_SYMBOL(scsi_req_abort_cmd);
  * @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.
  *
@@ -617,7 +675,7 @@ 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.
+         * We don't have to worry about this one timing out anymore.
          * 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
@@ -660,10 +718,11 @@ static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
         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.
  */
@@ -708,18 +767,14 @@ void scsi_finish_command(struct scsi_cmnd *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).
+/**
+ * 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
  *
@@ -742,8 +797,8 @@ 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 */
+        /* 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;
@@ -772,20 +827,17 @@ 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
  *
@@ -824,10 +876,10 @@ 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_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.
  */
@@ -849,8 +901,8 @@ 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)
@@ -867,7 +919,7 @@ 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)
 {
@@ -895,6 +947,8 @@ 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 device of @starget.  The devices have
  * a reference that must be released by scsi_host_put when breaking
@@ -946,13 +1000,13 @@ EXPORT_SYMBOL(__starget_for_each_device);
  * @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.
  *
- * 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,
@@ -974,9 +1028,9 @@ 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 @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_by_target(struct scsi_target *starget,
                                                  uint lun)
@@ -996,19 +1050,19 @@ 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,
@@ -1033,9 +1087,9 @@ 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)