block: loop: don't handle REQ_FUA explicitly

block core handles REQ_FUA by its flush state machine, so
won't do it in loop explicitly.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/loop.c

@@ -459,23 +459,15 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
 	pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
 
 	if (rq->cmd_flags & REQ_WRITE) {
-
 		if (rq->cmd_flags & REQ_FLUSH)
 			ret = lo_req_flush(lo, rq);
-
-		if (rq->cmd_flags & REQ_DISCARD) {
+		else if (rq->cmd_flags & REQ_DISCARD)
 			ret = lo_discard(lo, rq, pos);
-			goto out;
-		}
-
-		ret = lo_send(lo, rq, pos);
-
-		if ((rq->cmd_flags & REQ_FUA) && !ret)
-			ret = lo_req_flush(lo, rq);
+		else
+			ret = lo_send(lo, rq, pos);
 	} else
 		ret = lo_receive(lo, rq, lo->lo_blocksize, pos);
 
-out:
 	return ret;
 }