1 files changed, 16 insertions, 3 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 76e3702..923a913 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -242,9 +242,11 @@ int elevator_init(struct request_queue *q, char *name)
 {
 	struct elevator_type *e = NULL;
 	struct elevator_queue *eq;
-	int ret = 0;
 	void *data;
 
+	if (unlikely(q->elevator))
+		return 0;
+
 	INIT_LIST_HEAD(&q->queue_head);
 	q->last_merge = NULL;
 	q->end_sector = 0;
@@ -284,7 +286,7 @@ int elevator_init(struct request_queue *q, char *name)
 	}
 
 	elevator_attach(q, eq, data);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(elevator_init);
 
@@ -539,6 +541,15 @@ void elv_merge_requests(struct request_queue *q, struct request *rq,
 	q->last_merge = rq;
 }
 
+void elv_bio_merged(struct request_queue *q, struct request *rq,
+			struct bio *bio)
+{
+	struct elevator_queue *e = q->elevator;
+
+	if (e->ops->elevator_bio_merged_fn)
+		e->ops->elevator_bio_merged_fn(q, rq, bio);
+}
+
 void elv_requeue_request(struct request_queue *q, struct request *rq)
 {
 	/*
@@ -921,6 +932,7 @@ int elv_register_queue(struct request_queue *q)
 	}
 	return error;
 }
+EXPORT_SYMBOL(elv_register_queue);
 
 static void __elv_unregister_queue(struct elevator_queue *e)
 {
@@ -933,6 +945,7 @@ void elv_unregister_queue(struct request_queue *q)
 	if (q)
 		__elv_unregister_queue(q->elevator);
 }
+EXPORT_SYMBOL(elv_unregister_queue);
 
 void elv_register(struct elevator_type *e)
 {
@@ -1086,7 +1099,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
 	struct elevator_type *__e;
 	int len = 0;
 
-	if (!q->elevator)
+	if (!q->elevator || !blk_queue_stackable(q))
 		return sprintf(name, "none\n");
 
 	elv = e->elevator_type;