Function test_eventfd

test/defer-taskrun.c:68–118

static int test_eventfd(void)
{
	struct io_uring ring;
	int ret;
	int fda, fdb;
	struct io_uring_cqe *cqe;

	ret = io_uring_queue_init(8, &ring, IORING_SETUP_SINGLE_ISSUER |
					    IORING_SETUP_DEFER_TASKRUN);
	if (ret)
		return ret;

	fda = eventfd(0, EFD_NONBLOCK);
	fdb = eventfd(0, EFD_NONBLOCK);

	CHECK(fda >= 0 && fdb >= 0);

	ret = io_uring_register_eventfd(&ring, fda);
	if (ret)
		return ret;

	CHECK(!can_read(fda));
	CHECK(!can_read(fdb));

	io_uring_prep_poll_add(io_uring_get_sqe(&ring), fdb, POLLIN);
	io_uring_submit(&ring);
	CHECK(!can_read(fda)); /* poll should not have completed */

	io_uring_prep_nop(io_uring_get_sqe(&ring));
	io_uring_submit(&ring);
	CHECK(can_read(fda)); /* nop should have */

	CHECK(io_uring_peek_cqe(&ring, &cqe) == 0);
	CHECK(cqe->res == 0);
	io_uring_cqe_seen(&ring, cqe);
	eventfd_clear(fda);

	eventfd_trigger(fdb);
	/* can take time due to rcu_call */
	CHECK(can_read_t(fda, 1000));

	/* should not have processed the cqe yet */
	CHECK(io_uring_cq_ready(&ring) == 0);

	io_uring_get_events(&ring);
	CHECK(io_uring_cq_ready(&ring) == 1);


	io_uring_queue_exit(&ring);
	return 0;
}

struct thread_data {
	struct io_uring ring;