Function intr_event_add_handler

freebsd/kern/kern_intr.c:571–644

}

int
intr_event_add_handler(struct intr_event *ie, const char *name,
    driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
    enum intr_type flags, void **cookiep)
{
	struct intr_handler *ih, *temp_ih;
	struct intr_handler **prevptr;
	struct intr_thread *it;

	if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
		return (EINVAL);

	/* Allocate and populate an interrupt handler structure. */
	ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
	ih->ih_filter = filter;
	ih->ih_handler = handler;
	ih->ih_argument = arg;
	strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
	ih->ih_event = ie;
	ih->ih_pri = pri;
	if (flags & INTR_EXCL)
		ih->ih_flags = IH_EXCLUSIVE;
	if (flags & INTR_MPSAFE)
		ih->ih_flags |= IH_MPSAFE;
	if (flags & INTR_ENTROPY)
		ih->ih_flags |= IH_ENTROPY;
	if (flags & INTR_TYPE_NET)
		ih->ih_flags |= IH_NET;

	/* We can only have one exclusive handler in a event. */
	mtx_lock(&ie->ie_lock);
	if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
		if ((flags & INTR_EXCL) ||
		    (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
			mtx_unlock(&ie->ie_lock);
			free(ih, M_ITHREAD);
			return (EINVAL);
		}
	}

	/* Create a thread if we need one. */
	while (ie->ie_thread == NULL && handler != NULL) {
		if (ie->ie_flags & IE_ADDING_THREAD)
			msleep(ie, &ie->ie_lock, 0, "ithread", 0);
		else {
			ie->ie_flags |= IE_ADDING_THREAD;
			mtx_unlock(&ie->ie_lock);
			it = ithread_create("intr: newborn");
			mtx_lock(&ie->ie_lock);
			ie->ie_flags &= ~IE_ADDING_THREAD;
			ie->ie_thread = it;
			it->it_event = ie;
			ithread_update(it);
			wakeup(ie);
		}
	}

	/* Add the new handler to the event in priority order. */