get_futex_key
extern int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key,
ret = get_futex_key(uaddr, flags, &key, FUTEX_WRITE);
ret = get_futex_key(uaddr, flags, &q.key, FUTEX_WRITE);
ret = get_futex_key(uaddr1, flags1, &key1, FUTEX_READ);
ret = get_futex_key(uaddr2, flags2, &key2,
ret = get_futex_key(uaddr2, flags, &key2, FUTEX_WRITE);
ret = get_futex_key(uaddr, flags, &key, FUTEX_READ);
ret = get_futex_key(uaddr1, flags, &key1, FUTEX_READ);
ret = get_futex_key(uaddr2, flags, &key2, FUTEX_WRITE);
ret = get_futex_key(u64_to_user_ptr(vs[i].w.uaddr),
ret = get_futex_key(uaddr, flags, &q->key, FUTEX_READ);