Function zio_wait

freebsd/contrib/openzfs/module/zfs/zio.c:2211–2255

* ========================================================================== * Initiate I/O, either sync or async * ========================================================================== */

 * ==========================================================================
 */
int
zio_wait(zio_t *zio)
{
	/*
	 * Some routines, like zio_free_sync(), may return a NULL zio
	 * to avoid the performance overhead of creating and then destroying
	 * an unneeded zio.  For the callers' simplicity, we accept a NULL
	 * zio and ignore it.
	 */
	if (zio == NULL)
		return (0);

	long timeout = MSEC_TO_TICK(zfs_deadman_ziotime_ms);
	int error;

	ASSERT3S(zio->io_stage, ==, ZIO_STAGE_OPEN);
	ASSERT3P(zio->io_executor, ==, NULL);

	zio->io_waiter = curthread;
	ASSERT0(zio->io_queued_timestamp);
	zio->io_queued_timestamp = gethrtime();

	__zio_execute(zio);

	mutex_enter(&zio->io_lock);
	while (zio->io_executor != NULL) {
		error = cv_timedwait_io(&zio->io_cv, &zio->io_lock,
		    ddi_get_lbolt() + timeout);

		if (zfs_deadman_enabled && error == -1 &&
		    gethrtime() - zio->io_queued_timestamp >
		    spa_deadman_ziotime(zio->io_spa)) {
			mutex_exit(&zio->io_lock);
			timeout = MSEC_TO_TICK(zfs_deadman_checktime_ms);
			zio_deadman(zio, FTAG);
			mutex_enter(&zio->io_lock);
		}
	}
	mutex_exit(&zio->io_lock);

	error = zio->io_error;
	zio_destroy(zio);

	return (error);
}

void
zio_nowait(zio_t *zio)