int sock_register(const struct net_proto_family *ops)
{
	int err;

	if (ops->family >= NPROTO) {
		printk(KERN_CRIT "protocol %d >= NPROTO(%d)\n", ops->family,
		       NPROTO);
		return -ENOBUFS;
	}

	spin_lock(&net_family_lock);
	if (rcu_dereference_protected(net_families[ops->family],
				      lockdep_is_held(&net_family_lock)))
		err = -EEXIST;
	else {
		rcu_assign_pointer(net_families[ops->family], ops);
		err = 0;
	}
	spin_unlock(&net_family_lock);

	printk(KERN_INFO "NET: Registered protocol family %d\n", ops->family);
	return err;
}
int sock_register(const struct net_proto_family *ops)
{
	int err;

	if (ops->family >= NPROTO) {
		printk(KERN_CRIT "protocol %d >= NPROTO(%d)\n", ops->family,
		       NPROTO);
		return -ENOBUFS;
	}

	spin_lock(&net_family_lock);
	if (rcu_dereference_protected(net_families[ops->family],
				      lockdep_is_held(&net_family_lock)))
		err = -EEXIST;
	else {
		rcu_assign_pointer(net_families[ops->family], ops);
		err = 0;
	}
	spin_unlock(&net_family_lock);

	printk(KERN_INFO "NET: Registered protocol family %d\n", ops->family);
	return err;
}