1 files changed, 13 insertions, 0 deletions
diff --git a/block/elevator.c b/block/elevator.c
index ca86192..2d511f9 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -100,6 +100,19 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
 	if (bio_integrity(bio) != blk_integrity_rq(rq))
 		return 0;
 
+	/*
+	 * Don't merge if failfast settings don't match.
+	 *
+	 * FIXME: The negation in front of each condition is necessary
+	 * because bio and request flags use different bit positions
+	 * and the accessors return those bits directly.  This
+	 * ugliness will soon go away.
+	 */
+	if (!bio_failfast_dev(bio)	 != !blk_failfast_dev(rq)	||
+	    !bio_failfast_transport(bio) != !blk_failfast_transport(rq)	||
+	    !bio_failfast_driver(bio)	 != !blk_failfast_driver(rq))
+		return 0;
+
 	if (!elv_iosched_allow_merge(rq, bio))
 		return 0;