netfilter: nf_tables: fix error path in the init functions

We have to unregister chain type if this fails to register netns.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/nf_tables_ipv4.c

@@ -105,8 +105,14 @@ static const struct nf_chain_type filter_ipv4 = {
 
 static int __init nf_tables_ipv4_init(void)
 {
+	int ret;
+
 	nft_register_chain_type(&filter_ipv4);
-	return register_pernet_subsys(&nf_tables_ipv4_net_ops);
+	ret = register_pernet_subsys(&nf_tables_ipv4_net_ops);
+	if (ret < 0)
+		nft_unregister_chain_type(&filter_ipv4);
+
+	return ret;
 }
 
 static void __exit nf_tables_ipv4_exit(void)

net/ipv6/netfilter/nf_tables_ipv6.c

@@ -104,8 +104,14 @@ static const struct nf_chain_type filter_ipv6 = {
 
 static int __init nf_tables_ipv6_init(void)
 {
+	int ret;
+
 	nft_register_chain_type(&filter_ipv6);
-	return register_pernet_subsys(&nf_tables_ipv6_net_ops);
+	ret = register_pernet_subsys(&nf_tables_ipv6_net_ops);
+	if (ret < 0)
+		nft_unregister_chain_type(&filter_ipv6);
+
+	return ret;
 }
 
 static void __exit nf_tables_ipv6_exit(void)

net/netfilter/nf_tables_inet.c

@@ -80,8 +80,14 @@ static const struct nf_chain_type filter_inet = {
 
 static int __init nf_tables_inet_init(void)
 {
+	int ret;
+
 	nft_register_chain_type(&filter_inet);
-	return register_pernet_subsys(&nf_tables_inet_net_ops);
+	ret = register_pernet_subsys(&nf_tables_inet_net_ops);
+	if (ret < 0)
+		nft_unregister_chain_type(&filter_inet);
+
+	return ret;
 }
 
 static void __exit nf_tables_inet_exit(void)