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-rw-r--r--block/elevator.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 06e203426410..85d0d4adbb64 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -522,6 +522,10 @@ void elv_unregister_queue(struct request_queue *q)
int elv_register(struct elevator_type *e)
{
+ /* insert_requests and dispatch_request are mandatory */
+ if (WARN_ON_ONCE(!e->ops.insert_requests || !e->ops.dispatch_request))
+ return -EINVAL;
+
/* create icq_cache if requested */
if (e->icq_size) {
if (WARN_ON(e->icq_size < sizeof(struct io_cq)) ||