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/esas2r/esas2r_main.c b/drivers/scsi/esas2r/esas2r_main.c
index be09c62..a020b09 100644
--- a/drivers/scsi/esas2r/esas2r_main.c
+++ b/drivers/scsi/esas2r/esas2r_main.c
@@ -260,6 +260,7 @@
 	.change_queue_depth		= esas2r_change_queue_depth,
 	.change_queue_type		= scsi_change_queue_type,
 	.max_sectors			= 0xFFFF,
+	.use_blk_tags			= 1,
 };
 
 int sgl_page_size = 512;
@@ -1278,13 +1279,10 @@
 	esas2r_log_dev(ESAS2R_LOG_INFO, &(dev->sdev_gendev),
 		       "esas2r_slave_configure()");
 
-	if (dev->tagged_supported) {
-		scsi_set_tag_type(dev, MSG_SIMPLE_TAG);
-		scsi_activate_tcq(dev, cmd_per_lun);
-	} else {
-		scsi_set_tag_type(dev, 0);
-		scsi_deactivate_tcq(dev, cmd_per_lun);
-	}
+	if (dev->tagged_supported)
+		scsi_adjust_queue_depth(dev, MSG_SIMPLE_TAG, cmd_per_lun);
+	else
+		scsi_adjust_queue_depth(dev, 0, cmd_per_lun);
 
 	return 0;
 }