timed_fence
struct timed_fence tf;
struct timed_fence *tf = timer_container_of(tf, t, timer);
void timed_fence_init(struct timed_fence *tf, unsigned long expires)
void timed_fence_fini(struct timed_fence *tf)
void timed_fence_init(struct timed_fence *tf, unsigned long expires);
void timed_fence_fini(struct timed_fence *tf);