static struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
{
	struct xfrm_state_afinfo *afinfo;
	struct xfrm_mode *mode;
	int modload_attempted = 0;

	if (unlikely(encap >= XFRM_MODE_MAX))
		return NULL;

retry:
	afinfo = xfrm_state_get_afinfo(family);
	if (unlikely(afinfo == NULL))
		return NULL;

	mode = READ_ONCE(afinfo->mode_map[encap]);
	if (unlikely(mode && !try_module_get(mode->owner)))
		mode = NULL;

	rcu_read_unlock();
	if (!mode && !modload_attempted) {
		request_module("xfrm-mode-%d-%d", family, encap);
		modload_attempted = 1;
		goto retry;
	}

	return mode;
}
Unknown