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Diffstat (limited to 'drivers/ata/libata-scsi.c')
-rw-r--r--drivers/ata/libata-scsi.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index aa6cb6dcec41..48e388800f5a 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -987,29 +987,32 @@ int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth)
struct ata_port *ap = ata_shost_to_port(sdev->host);
struct ata_device *dev;
unsigned long flags;
- int max_depth;
- if (queue_depth < 1)
+ if (queue_depth < 1 || queue_depth == sdev->queue_depth)
return sdev->queue_depth;
dev = ata_scsi_find_dev(ap, sdev);
if (!dev || !ata_dev_enabled(dev))
return sdev->queue_depth;
- max_depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
- max_depth = min(ATA_MAX_QUEUE - 1, max_depth);
- if (queue_depth > max_depth)
- queue_depth = max_depth;
-
- scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, queue_depth);
-
+ /* NCQ enabled? */
spin_lock_irqsave(ap->lock, flags);
- if (queue_depth > 1)
- dev->flags &= ~ATA_DFLAG_NCQ_OFF;
- else
+ dev->flags &= ~ATA_DFLAG_NCQ_OFF;
+ if (queue_depth == 1 || !ata_ncq_enabled(dev)) {
dev->flags |= ATA_DFLAG_NCQ_OFF;
+ queue_depth = 1;
+ }
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 - 1);
+
+ if (sdev->queue_depth == queue_depth)
+ return -EINVAL;
+
+ scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, queue_depth);
return queue_depth;
}