Function intr_handler_barrier

freebsd/kern/kern_intr.c:760–780

}

static void
intr_handler_barrier(struct intr_handler *handler)
{
	struct intr_event *ie;

	ie = handler->ih_event;
	mtx_assert(&ie->ie_lock, MA_OWNED);
	KASSERT((handler->ih_flags & IH_DEAD) == 0,
	    ("update for a removed handler"));

	if (ie->ie_thread == NULL) {
		intr_event_barrier(ie);
		return;
	}
	if ((handler->ih_flags & IH_CHANGED) == 0) {
		handler->ih_flags |= IH_CHANGED;
		intr_event_schedule_thread(ie);
	}
	while ((handler->ih_flags & IH_CHANGED) != 0)
		msleep(handler, &ie->ie_lock, 0, "ih_barr", 0);
}

/*
 * Sleep until an ithread finishes executing an interrupt handler.