extern void elv_dispatch_add_tail(struct request_queue *, struct request *);
extern void elv_add_request(struct request_queue *, struct request *, int);
extern void __elv_add_request(struct request_queue *, struct request *, int);
-extern void elv_insert(struct request_queue *, struct request *, int);
extern int elv_merge(struct request_queue *, struct request **, struct bio *);
extern int elv_try_merge(struct request *, struct bio *);
extern void elv_merge_requests(struct request_queue *, struct request *,