1 files changed, 13 insertions, 0 deletions

diff --git a/block/elevator.c b/block/elevator.c
index ca861927ba41..2d511f9105e1 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;