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authorChristoph Hellwig <hch@lst.de>2014-10-02 14:39:55 +0200
committerChristoph Hellwig <hch@lst.de>2014-11-12 11:19:39 +0100
commita62182f338b39a22035531c6afc0a8d2928b1df2 (patch)
tree57ca6cea82a09d2655daf5c161024c5015373646 /drivers/scsi/scsi.c
parent1d5203284d8acbdfdf9b478d434450b34f338f28 (diff)
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>
Diffstat (limited to 'drivers/scsi/scsi.c')
-rw-r--r--drivers/scsi/scsi.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index bc52bbd97381..9baeff03dd9b 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -867,6 +867,26 @@ int scsi_track_queue_full(struct scsi_device *sdev, int depth)
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