void *tq_pop(struct thread_q *tq, const struct timespec *abstime)
{
	struct tq_ent *ent;
	void *rval = NULL;
	int rc;

	mutex_lock(&tq->mutex);

	if (!list_empty(&tq->q))
		goto pop;

	if (abstime)
		rc = pthread_cond_timedwait(&tq->cond, &tq->mutex, abstime);
	else
		rc = pthread_cond_wait(&tq->cond, &tq->mutex);
	if (rc)
		goto out;
	if (list_empty(&tq->q))
		goto out;

pop:
	ent = list_entry(tq->q.next, struct tq_ent, q_node);
	rval = ent->data;

	list_del(&ent->q_node);
	free(ent);

out:
	mutex_unlock(&tq->mutex);
	return rval;
}
Unknown