[SCSI] do not manipulate device reference counts in scsi_get/put_command

Many callers won't need this and we can optimize them away.  In addition
the handling in the __-prefixed variants was inconsistant to start with.

Based on an earlier patch from Bart Van Assche.

[jejb: fix kerneldoc probelm picked up by Fengguang Wu]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 12 insertions, 25 deletions

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fb86479ffd4..2b12983d2b2 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -284,27 +284,19 @@ EXPORT_SYMBOL_GPL(__scsi_get_command);
  */
 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
 {
-	struct scsi_cmnd *cmd;
+	struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
+	unsigned long flags;
 
-	/* Bail if we can't get a reference to the device */
-	if (!get_device(&dev->sdev_gendev))
+	if (unlikely(cmd == NULL))
 		return NULL;
 
-	cmd = __scsi_get_command(dev->host, gfp_mask);
-
-	if (likely(cmd != NULL)) {
-		unsigned long flags;
-
-		cmd->device = dev;
-		INIT_LIST_HEAD(&cmd->list);
-		INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
-		spin_lock_irqsave(&dev->list_lock, flags);
-		list_add_tail(&cmd->list, &dev->cmd_list);
-		spin_unlock_irqrestore(&dev->list_lock, flags);
-		cmd->jiffies_at_alloc = jiffies;
-	} else
-		put_device(&dev->sdev_gendev);
-
+	cmd->device = dev;
+	INIT_LIST_HEAD(&cmd->list);
+	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
+	spin_lock_irqsave(&dev->list_lock, flags);
+	list_add_tail(&cmd->list, &dev->cmd_list);
+	spin_unlock_irqrestore(&dev->list_lock, flags);
+	cmd->jiffies_at_alloc = jiffies;
 	return cmd;
 }
 EXPORT_SYMBOL(scsi_get_command);
@@ -313,10 +305,8 @@ 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)
+void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 {
 	unsigned long flags;
 
@@ -331,8 +321,6 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
 
 	if (likely(cmd != NULL))
 		scsi_pool_free_command(shost->cmd_pool, cmd);
-
-	put_device(dev);
 }
 EXPORT_SYMBOL(__scsi_put_command);
 
@@ -346,7 +334,6 @@ EXPORT_SYMBOL(__scsi_put_command);
  */
 void scsi_put_command(struct scsi_cmnd *cmd)
 {
-	struct scsi_device *sdev = cmd->device;
 	unsigned long flags;
 
 	/* serious error if the command hasn't come from a device list */
@@ -357,7 +344,7 @@ void scsi_put_command(struct scsi_cmnd *cmd)
 
 	cancel_delayed_work(&cmd->abort_work);
 
-	__scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
+	__scsi_put_command(cmd->device->host, cmd);
 }
 EXPORT_SYMBOL(scsi_put_command);