diff --git a/block/blk-merge.c b/block/blk-merge.c
index 044bff9afa5e724147bddd530250b82c2abf1bff..d24a6c9398ed80767fe379ad88b7d9c096134b6e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -477,13 +477,20 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 }
 EXPORT_SYMBOL(blk_rq_map_sg);
 
+static inline unsigned int blk_rq_get_max_segments(struct request *rq)
+{
+	if (req_op(rq) == REQ_OP_DISCARD)
+		return queue_max_discard_segments(rq->q);
+	return queue_max_segments(rq->q);
+}
+
 static inline int ll_new_hw_segment(struct request_queue *q,
 				    struct request *req,
 				    struct bio *bio)
 {
 	int nr_phys_segs = bio_phys_segments(q, bio);
 
-	if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q))
+	if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req))
 		goto no_merge;
 
 	if (blk_integrity_merge_bio(q, req, bio) == false)
@@ -606,7 +613,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 		total_phys_segments--;
 	}
 
-	if (total_phys_segments > queue_max_segments(q))
+	if (total_phys_segments > blk_rq_get_max_segments(req))
 		return 0;
 
 	if (blk_integrity_merge_rq(q, req, next) == false)