Function get_sqe

examples/proxy.c:656–671

* Special cased for SQPOLL only, as we don't control when SQEs are consumed if * that is used. Hence we may need to wait for the SQPOLL thread to keep up * until we can get a new SQE. All other cases will break immediately, with a * fresh SQE. * * If we grossly undersized our SQ ring, getting a NULL sqe can happen even * for the !SQPOLL case if we're handling a lot of CQEs in our event loop

 * a single submission cycle.
 */
static struct io_uring_sqe *get_sqe(struct io_uring *ring)
{
	struct io_uring_sqe *sqe;

	do {
		sqe = io_uring_get_sqe(ring);
		if (sqe)
			break;
		if (!sqpoll)
			io_uring_submit(ring);
		else
			io_uring_sqring_wait(ring);
	} while (1);

	return sqe;
}

/*
 * See __encode_userdata() for how we encode sqe->user_data, which is passed