scsi: always assign block layer tags if enabled

Allow a driver to ask for block layer tags by setting .use_blk_tags in the
host template, in which case it will always see a valid value in
request->tag, similar to the behavior when using blk-mq.  This means even
SCSI "untagged" commands will now have a tag, which is especially useful
when using a host-wide tag map.

Signed-off-by: Christoph Hellwig <hch@lst.de>
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/csiostor/csio_scsi.c b/drivers/scsi/csiostor/csio_scsi.c
index 8231505..f73155d 100644
--- a/drivers/scsi/csiostor/csio_scsi.c
+++ b/drivers/scsi/csiostor/csio_scsi.c
@@ -2241,11 +2241,7 @@
 static int
 csio_slave_configure(struct scsi_device *sdev)
 {
-	if (sdev->tagged_supported)
-		scsi_activate_tcq(sdev, csio_lun_qdepth);
-	else
-		scsi_deactivate_tcq(sdev, csio_lun_qdepth);
-
+	scsi_adjust_queue_depth(sdev, 0, csio_lun_qdepth);
 	return 0;
 }
 
@@ -2290,6 +2286,7 @@
 	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= csio_fcoe_lport_attrs,
 	.max_sectors		= CSIO_MAX_SECTOR_SIZE,
+	.use_blk_tags		= 1,
 };
 
 struct scsi_host_template csio_fcoe_shost_vport_template = {
@@ -2309,6 +2306,7 @@
 	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= csio_fcoe_vport_attrs,
 	.max_sectors		= CSIO_MAX_SECTOR_SIZE,
+	.use_blk_tags		= 1,
 };
 
 /*