Read the current counter and removes wait queue.
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx * ctx, wait_queue_t * wait, __u64 * cnt);
ctx
[in] Pointer to eventfd context.
wait
[in] Wait queue to be removed.
cnt
[out] Pointer to the 64-bit counter value.
Returns 0 if successful, or the following error codes:
-EAGAIN : The operation would have blocked.
This is used to atomically remove a wait queue entry from the eventfd wait queue head, and read/reset the counter value.