diff --git a/block/blk-mq.c b/block/blk-mq.c
index b04ff6f56926..953f08354c8c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -681,6 +681,21 @@ out_queue_exit:
 }
 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
 
+static void blk_mq_finish_request(struct request *rq)
+{
+	struct request_queue *q = rq->q;
+
+	if (rq->rq_flags & RQF_USE_SCHED) {
+		q->elevator->type->ops.finish_request(rq);
+		/*
+		 * For postflush request that may need to be
+		 * completed twice, we should clear this flag
+		 * to avoid double finish_request() on the rq.
+		 */
+		rq->rq_flags &= ~RQF_USE_SCHED;
+	}
+}
+
 static void __blk_mq_free_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;
@@ -707,9 +722,7 @@ void blk_mq_free_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;
 
-	if ((rq->rq_flags & RQF_USE_SCHED) &&
-	    q->elevator->type->ops.finish_request)
-		q->elevator->type->ops.finish_request(rq);
+	blk_mq_finish_request(rq);
 
 	if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
 		laptop_io_completion(q->disk->bdi);
@@ -1020,6 +1033,8 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
 	if (blk_mq_need_time_stamp(rq))
 		__blk_mq_end_request_acct(rq, ktime_get_ns());
 
+	blk_mq_finish_request(rq);
+
 	if (rq->end_io) {
 		rq_qos_done(rq->q, rq);
 		if (rq->end_io(rq, error) == RQ_END_IO_FREE)
@@ -1074,6 +1089,8 @@ void blk_mq_end_request_batch(struct io_comp_batch *iob)
 		if (iob->need_ts)
 			__blk_mq_end_request_acct(rq, now);
 
+		blk_mq_finish_request(rq);
+
 		rq_qos_done(rq->q, rq);
 
 		/*
diff --git a/block/elevator.c b/block/elevator.c
index 8400e303fbcb..5ff093cb3cf8 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -499,6 +499,9 @@ void elv_unregister_queue(struct request_queue *q)
 
 int elv_register(struct elevator_type *e)
 {
+	/* finish request is mandatory */
+	if (WARN_ON_ONCE(!e->ops.finish_request))
+		return -EINVAL;
 	/* insert_requests and dispatch_request are mandatory */
 	if (WARN_ON_ONCE(!e->ops.insert_requests || !e->ops.dispatch_request))
 		return -EINVAL;