extern struct io_u *__get_io_u(struct thread_data *);
extern struct io_u *get_io_u(struct thread_data *);
extern void put_io_u(struct thread_data *, struct io_u *);
+extern void clear_io_u(struct thread_data *, struct io_u *);
extern void requeue_io_u(struct thread_data *, struct io_u **);
extern int __must_check io_u_sync_complete(struct thread_data *, struct io_u *, unsigned long *);
extern int __must_check io_u_queued_complete(struct thread_data *, int, unsigned long *);