elevator: make elevator_init_fn() return 0/-errno

elevator_ops->elevator_init_fn() has a weird return value.  It returns
a void * which the caller should assign to q->elevator->elevator_data
and %NULL return denotes init failure.

Update such that it returns integer 0/-errno and sets elevator_data
directly as necessary.

This makes the interface more conventional and eases further cleanup.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 7d4e0356f329..97fb2557a18c 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -33,7 +33,7 @@ typedef void (elevator_put_req_fn) (struct request *);
 typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
 typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
 
-typedef void *(elevator_init_fn) (struct request_queue *);
+typedef int (elevator_init_fn) (struct request_queue *);
 typedef void (elevator_exit_fn) (struct elevator_queue *);
 
 struct elevator_ops