1 files changed, 31 insertions, 19 deletions

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index f3e7396e3191..6c07025011ed 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -1023,7 +1023,6 @@ EXPORT_SYMBOL_GPL(dev_attr_sw_activity);
 /**
  *	ata_change_queue_depth - Set a device maximum queue depth
  *	@ap: ATA port of the target device
- *	@dev: target ATA device
  *	@sdev: SCSI device to configure queue depth for
  *	@queue_depth: new queue depth
  *
@@ -1031,33 +1030,47 @@ EXPORT_SYMBOL_GPL(dev_attr_sw_activity);
  *	and libata.
  *
  */
-int ata_change_queue_depth(struct ata_port *ap, struct ata_device *dev,
-			   struct scsi_device *sdev, int queue_depth)
+int ata_change_queue_depth(struct ata_port *ap, struct scsi_device *sdev,
+			   int queue_depth)
 {
+	struct ata_device *dev;
 	unsigned long flags;
+	int max_queue_depth;
 
-	if (!dev || !ata_dev_enabled(dev))
-		return sdev->queue_depth;
+	spin_lock_irqsave(ap->lock, flags);
 
-	if (queue_depth < 1 || queue_depth == sdev->queue_depth)
+	dev = ata_scsi_find_dev(ap, sdev);
+	if (!dev || queue_depth < 1 || queue_depth == sdev->queue_depth) {
+		spin_unlock_irqrestore(ap->lock, flags);
 		return sdev->queue_depth;
+	}
 
-	/* NCQ enabled? */
-	spin_lock_irqsave(ap->lock, flags);
-	dev->flags &= ~ATA_DFLAG_NCQ_OFF;
-	if (queue_depth == 1 || !ata_ncq_enabled(dev)) {
+	/*
+	 * Make sure that the queue depth requested does not exceed the device
+	 * capabilities.
+	 */
+	max_queue_depth = min(ATA_MAX_QUEUE, sdev->host->can_queue);
+	max_queue_depth = min(max_queue_depth, ata_id_queue_depth(dev->id));
+	if (queue_depth > max_queue_depth) {
+		spin_unlock_irqrestore(ap->lock, flags);
+		return -EINVAL;
+	}
+
+	/*
+	 * If NCQ is not supported by the device or if the target queue depth
+	 * is 1 (to disable drive side command queueing), turn off NCQ.
+	 */
+	if (queue_depth == 1 || !ata_ncq_supported(dev)) {
 		dev->flags |= ATA_DFLAG_NCQ_OFF;
 		queue_depth = 1;
+	} else {
+		dev->flags &= ~ATA_DFLAG_NCQ_OFF;
 	}
-	spin_unlock_irqrestore(ap->lock, flags);
 
-	/* limit and apply queue depth */
-	queue_depth = min(queue_depth, sdev->host->can_queue);
-	queue_depth = min(queue_depth, ata_id_queue_depth(dev->id));
-	queue_depth = min(queue_depth, ATA_MAX_QUEUE);
+	spin_unlock_irqrestore(ap->lock, flags);
 
-	if (sdev->queue_depth == queue_depth)
-		return -EINVAL;
+	if (queue_depth == sdev->queue_depth)
+		return sdev->queue_depth;
 
 	return scsi_change_queue_depth(sdev, queue_depth);
 }
@@ -1082,8 +1095,7 @@ int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth)
 {
 	struct ata_port *ap = ata_shost_to_port(sdev->host);
 
-	return ata_change_queue_depth(ap, ata_scsi_find_dev(ap, sdev),
-				      sdev, queue_depth);
+	return ata_change_queue_depth(ap, sdev, queue_depth);
 }
 EXPORT_SYMBOL_GPL(ata_scsi_change_queue_depth);