Re: [PATCH net-next V4 4/4] net/sched: Introduce act_tunnel_key

+static int tunnel_key_init(struct net *net, struct nlattr *nla,
+			   struct nlattr *est, struct tc_action **a,
+			   int ovr, int bind)
+{
+	struct tc_action_net *tn = net_generic(net, tunnel_key_net_id);
+	struct nlattr *tb[TCA_TUNNEL_KEY_MAX + 1];
+	struct metadata_dst *metadata = NULL;
+	struct tc_tunnel_key *parm;
+	struct tcf_tunnel_key *t;
+	struct tcf_tunnel_key_params *params_old;
+	struct tcf_tunnel_key_params *params_new;
+	__be64 key_id;
+	bool exists = false;
+	int ret = 0;
+	int err;
+
+	if (!nla)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_TUNNEL_KEY_MAX, nla, tunnel_key_policy);
+	if (err < 0)
+		return err;
+
+	if (!tb[TCA_TUNNEL_KEY_PARMS])
+		return -EINVAL;
+
+	parm = nla_data(tb[TCA_TUNNEL_KEY_PARMS]);
+	exists = tcf_hash_check(tn, parm->index, a, bind);
+	if (exists && bind)
+		return 0;
+
+	switch (parm->t_action) {
+	case TCA_TUNNEL_KEY_ACT_RELEASE:
+		break;
+	case TCA_TUNNEL_KEY_ACT_SET:
+		if (!tb[TCA_TUNNEL_KEY_ENC_KEY_ID]) {
+			ret = -EINVAL;
+			goto err_out;
+		}
+
+		key_id = key32_to_tunnel_id(nla_get_be32(tb[TCA_TUNNEL_KEY_ENC_KEY_ID]));
+
+		if (tb[TCA_TUNNEL_KEY_ENC_IPV4_SRC] &&
+		    tb[TCA_TUNNEL_KEY_ENC_IPV4_DST]) {
+			__be32 saddr;
+			__be32 daddr;
+
+			saddr = nla_get_in_addr(tb[TCA_TUNNEL_KEY_ENC_IPV4_SRC]);
+			daddr = nla_get_in_addr(tb[TCA_TUNNEL_KEY_ENC_IPV4_DST]);
+
+			metadata = __ip_tun_set_dst(saddr, daddr, 0, 0,
+						    TUNNEL_KEY, key_id, 0);
+		} else if (tb[TCA_TUNNEL_KEY_ENC_IPV6_SRC] &&
+			   tb[TCA_TUNNEL_KEY_ENC_IPV6_DST]) {
+			struct in6_addr saddr;
+			struct in6_addr daddr;
+
+			saddr = nla_get_in6_addr(tb[TCA_TUNNEL_KEY_ENC_IPV6_SRC]);
+			daddr = nla_get_in6_addr(tb[TCA_TUNNEL_KEY_ENC_IPV6_DST]);
+
+			metadata = __ipv6_tun_set_dst(&saddr, &daddr, 0, 0, 0,
+						      TUNNEL_KEY, key_id, 0);
+		}
+
+		if (!metadata) {
+			ret = -EINVAL;
+			goto err_out;
+		}
+
+		metadata->u.tun_info.mode |= IP_TUNNEL_INFO_TX;
+		break;
+	default:
+		goto err_out;
+	}
+
+	if (!exists) {
+		ret = tcf_hash_create(tn, parm->index, est, a,
+				      &act_tunnel_key_ops, bind, true);
+		if (ret)
+			return ret;
+
+		ret = ACT_P_CREATED;
+	} else {
+		tcf_hash_release(*a, bind);
+		if (!ovr)
+			return -EEXIST;
+	}
+
+	t = to_tunnel_key(*a);
+
+	ASSERT_RTNL();
+	params_new = kzalloc(sizeof(*params_new),
+			     GFP_KERNEL);

+	if (unlikely(!params_new)) {
+		if (ovr)
+			tcf_hash_release(*a, bind);
+		return -ENOMEM;

+	}
+
+	params_old = rtnl_dereference(t->params);
+
+	t->tcf_action = parm->action;
+	params_new->tcft_action = parm->t_action;
+	params_new->tcft_enc_metadata = metadata;
+
+	rcu_assign_pointer(t->params, params_new);
+
+	if (params_old)
+		kfree_rcu(params_old, rcu);
+
+	if (ret == ACT_P_CREATED)
+		tcf_hash_insert(tn, *a);
+
+	return ret;
+
+err_out:
+	if (exists)
+		tcf_hash_release(*a, bind);
+	return ret;
+}
+
+static void tunnel_key_release(struct tc_action *a, int bind)
+{
+	struct tcf_tunnel_key *t = to_tunnel_key(a);
+	struct tcf_tunnel_key_params *params;
+
+	rcu_read_lock();
+	params = rcu_dereference(t->params);
+
+	if (params->tcft_action == TCA_TUNNEL_KEY_ACT_SET)
+		dst_release(&params->tcft_enc_metadata->dst);
+
+	rcu_read_unlock();