scsi: provide a generic change_queue_type method
Most drivers use exactly the same implementation, so provide it as a
library function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index bc52bbd..9baeff0 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -867,6 +867,26 @@
EXPORT_SYMBOL(scsi_track_queue_full);
/**
+ * scsi_change_queue_type() - Change a device's queue type
+ * @sdev: The SCSI device whose queue depth is to change
+ * @tag_type: Identifier for queue type
+ */
+int scsi_change_queue_type(struct scsi_device *sdev, int tag_type)
+{
+ if (sdev->tagged_supported) {
+ scsi_set_tag_type(sdev, tag_type);
+ if (tag_type)
+ scsi_activate_tcq(sdev, sdev->queue_depth);
+ else
+ scsi_deactivate_tcq(sdev, sdev->queue_depth);
+ } else
+ tag_type = 0;
+
+ return tag_type;
+}
+EXPORT_SYMBOL(scsi_change_queue_type);
+
+/**
* scsi_vpd_inquiry - Request a device provide us with a VPD page
* @sdev: The device to ask
* @buffer: Where to put the result