Eventfd_ctx_remove_wait_queue (9) Linux Manual Page

eventfd_ctx_remove_wait_queue – Read the current counter and removes wait queue.

Synopsis

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.