diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a2e496f..bd55b1d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -630,6 +630,9 @@
 static inline void elv_dispatch_add_tail(struct request_queue *q,
 					 struct request *rq)
 {
+	if (q->last_merge == rq)
+		q->last_merge = NULL;
+
 	q->end_sector = rq_end_sector(rq);
 	q->boundary_rq = rq;
 	list_add_tail(&rq->queuelist, &q->queue_head);