X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fscsi%2Fscsi_lib.c;h=6c4b620ac3c1152f6fdc49acd8f902c10af02e79;hb=c6e92669dd2703bd2243c2b16cd5a5283135151b;hp=f85cfa6c47b5212982bcbfcd9065936c27360f3d;hpb=9545eb61e5bb70055fd9358f25f95387f7398cba;p=pandora-kernel.git

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f85cfa6c47b5..6c4b620ac3c1 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -406,10 +406,6 @@ static void scsi_run_queue(struct request_queue *q)
 	LIST_HEAD(starved_list);
 	unsigned long flags;
 
-	/* if the device is dead, sdev will be NULL, so no queue to run */
-	if (!sdev)
-		return;
-
 	shost = sdev->host;
 	if (scsi_target(sdev)->single_lun)
 		scsi_single_lun_run(sdev);
@@ -483,15 +479,26 @@ void scsi_requeue_run_queue(struct work_struct *work)
  */
 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
 {
+	struct scsi_device *sdev = cmd->device;
 	struct request *req = cmd->request;
 	unsigned long flags;
 
+	/*
+	 * We need to hold a reference on the device to avoid the queue being
+	 * killed after the unlock and before scsi_run_queue is invoked which
+	 * may happen because scsi_unprep_request() puts the command which
+	 * releases its reference on the device.
+	 */
+	get_device(&sdev->sdev_gendev);
+
 	spin_lock_irqsave(q->queue_lock, flags);
 	scsi_unprep_request(req);
 	blk_requeue_request(q, req);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
 	scsi_run_queue(q);
+
+	put_device(&sdev->sdev_gendev);
 }
 
 void scsi_next_command(struct scsi_cmnd *cmd)
@@ -1374,24 +1381,27 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
  * may be changed after request stacking drivers call the function,
  * regardless of taking lock or not.
  *
- * When scsi can't dispatch I/Os anymore and needs to kill I/Os
- * (e.g. !sdev), scsi needs to return 'not busy'.
- * Otherwise, request stacking drivers may hold requests forever.
+ * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
+ * needs to return 'not busy'. Otherwise, request stacking drivers
+ * may hold requests forever.
  */
 static int scsi_lld_busy(struct request_queue *q)
 {
 	struct scsi_device *sdev = q->queuedata;
 	struct Scsi_Host *shost;
-	struct scsi_target *starget;
 
-	if (!sdev)
+	if (blk_queue_dead(q))
 		return 0;
 
 	shost = sdev->host;
-	starget = scsi_target(sdev);
 
-	if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) ||
-	    scsi_target_is_busy(starget) || scsi_device_is_busy(sdev))
+	/*
+	 * Ignore host/starget busy state.
+	 * Since block layer does not have a concept of fairness across
+	 * multiple queues, congestion of host/starget needs to be handled
+	 * in SCSI layer.
+	 */
+	if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
 		return 1;
 
 	return 0;
@@ -1491,12 +1501,6 @@ static void scsi_request_fn(struct request_queue *q)
 	struct scsi_cmnd *cmd;
 	struct request *req;
 
-	if (!sdev) {
-		while ((req = blk_peek_request(q)) != NULL)
-			scsi_kill_request(req, q);
-		return;
-	}
-
 	if(!get_device(&sdev->sdev_gendev))
 		/* We must be tearing the block queue down already */
 		return;
@@ -1698,20 +1702,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
 	return q;
 }
 
-void scsi_free_queue(struct request_queue *q)
-{
-	unsigned long flags;
-
-	WARN_ON(q->queuedata);
-
-	/* cause scsi_request_fn() to kill all non-finished requests */
-	spin_lock_irqsave(q->queue_lock, flags);
-	q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	blk_cleanup_queue(q);
-}
-
 /*
  * Function:    scsi_block_requests()
  *