Subject: [PATCH v3 net 5/6] mpls: Handle error of rtnl_register_module().

From: Kuniyuki Iwashima <[email-masked]>
Date: Mon, 7 Oct 2024 05:44:58 -0700

Since introduced, mpls_init() has been ignoring the returned
value of rtnl_register_module(), which could fail.

Let's handle the errors by rtnl_register_many().

Fixes: 03c0566542f4 ("mpls: Netlink commands to add, remove, and dump routes")
Signed-off-by: Kuniyuki Iwashima <[email-masked]>
---
Cc: "Eric W. Biederman" <[email-masked]>
---
 net/mpls/af_mpls.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index aba983531ed3..df62638b6498 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -2728,6 +2728,15 @@ static struct rtnl_af_ops mpls_af_ops __read_mostly = {
 	.get_stats_af_size = mpls_get_stats_af_size,
 };
 
+static const struct rtnl_msg_handler mpls_rtnl_msg_handlers[] __initdata_or_module = {
+	{THIS_MODULE, PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, 0},
+	{THIS_MODULE, PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, 0},
+	{THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes, 0},
+	{THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
+	 mpls_netconf_get_devconf, mpls_netconf_dump_devconf,
+	 RTNL_FLAG_DUMP_UNLOCKED},
+};
+
 static int __init mpls_init(void)
 {
 	int err;
@@ -2746,24 +2755,25 @@ static int __init mpls_init(void)
 
 	rtnl_af_register(&mpls_af_ops);
 
-	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_NEWROUTE,
-			     mpls_rtm_newroute, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_DELROUTE,
-			     mpls_rtm_delroute, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETROUTE,
-			     mpls_getroute, mpls_dump_routes, 0);
-	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
-			     mpls_netconf_get_devconf,
-			     mpls_netconf_dump_devconf,
-			     RTNL_FLAG_DUMP_UNLOCKED);
-	err = ipgre_tunnel_encap_add_mpls_ops();
+	err = rtnl_register_many(mpls_rtnl_msg_handlers);
 	if (err)
+		goto out_unregister_rtnl_af;
+
+	err = ipgre_tunnel_encap_add_mpls_ops();
+	if (err) {
 		pr_err("Can't add mpls over gre tunnel ops\n");
+		goto out_unregister_rtnl;
+	}
 
 	err = 0;
 out:
 	return err;
 
+out_unregister_rtnl:
+	rtnl_unregister_many(mpls_rtnl_msg_handlers);
+out_unregister_rtnl_af:
+	rtnl_af_unregister(&mpls_af_ops);
+	dev_remove_pack(&mpls_packet_type);
 out_unregister_pernet:
 	unregister_pernet_subsys(&mpls_net_ops);
 	goto out;
-- 
2.30.2