Function intr_event_remove_handler

freebsd/kern/kern_intr.c:821–901

}

int
intr_event_remove_handler(void *cookie)
{
	struct intr_handler *handler = (struct intr_handler *)cookie;
	struct intr_event *ie;
	struct intr_handler *ih;
	struct intr_handler **prevptr;
#ifdef notyet
	int dead;
#endif

	if (handler == NULL)
		return (EINVAL);
	ie = handler->ih_event;
	KASSERT(ie != NULL,
	    ("interrupt handler \"%s\" has a NULL interrupt event",
	    handler->ih_name));

	mtx_lock(&ie->ie_lock);
	CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
	    ie->ie_name);
	CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
		if (ih == handler)
			break;
	}
	if (ih == NULL) {
		panic("interrupt handler \"%s\" not found in "
		    "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
	}

	/*
	 * If there is no ithread, then directly remove the handler.  Note that
	 * intr_event_handle() iterates ie_handlers in a lock-less fashion, so
	 * care needs to be taken to keep ie_handlers consistent and to free
	 * the removed handler only when ie_handlers is quiescent.
	 */
	if (ie->ie_thread == NULL) {
		CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
		intr_event_barrier(ie);
		intr_event_update(ie);
		mtx_unlock(&ie->ie_lock);
		free(handler, M_ITHREAD);
		return (0);
	}

	/*
	 * Let the interrupt thread do the job.
	 * The interrupt source is disabled when the interrupt thread is
	 * running, so it does not have to worry about interaction with
	 * intr_event_handle().
	 */
	KASSERT((handler->ih_flags & IH_DEAD) == 0,
	    ("duplicate handle remove"));
	handler->ih_flags |= IH_DEAD;
	intr_event_schedule_thread(ie);
	while (handler->ih_flags & IH_DEAD)
		msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
	intr_event_update(ie);