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/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 1bc5df4..ee69b82 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -799,8 +799,7 @@
 	if (devinfo->flags & US_FL_NO_REPORT_OPCODES)
 		sdev->no_report_opcodes = 1;
 
-	scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
-	scsi_activate_tcq(sdev, devinfo->qdepth - 2);
+	scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, devinfo->qdepth - 2);
 	return 0;
 }
 
@@ -824,6 +823,7 @@
 	 * allocator.
 	 */
 	.disable_blk_mq = true,
+	.use_blk_tags = 1,
 };
 
 #define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \