[PATCH net] ipv4: nexthop: handle errors in nexthop_init()

[Minhong He]

nexthop_init() ignores errors from register_pernet_subsys(),
register_netdevice_notifier() and rtnl_register_many(), so a partial
initialization can appear successful.

Check each step and unwind the registrations that already succeeded.

Signed-off-by: Minhong He <heminhong@xxxxxxxxxx>
---
 net/ipv4/nexthop.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 6205bd57aa85..0ad40d93e3b5 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -4192,12 +4192,26 @@ static const struct rtnl_msg_handler nexthop_rtnl_msg_handlers[] __initconst = {
 
 static int __init nexthop_init(void)
 {
-	register_pernet_subsys(&nexthop_net_ops);
+	int err;
+
+	err = register_pernet_subsys(&nexthop_net_ops);
+	if (err)
+		return err;
 
-	register_netdevice_notifier(&nh_netdev_notifier);
+	err = register_netdevice_notifier(&nh_netdev_notifier);
+	if (err)
+		goto err_unregister_pernet;
 
-	rtnl_register_many(nexthop_rtnl_msg_handlers);
+	err = rtnl_register_many(nexthop_rtnl_msg_handlers);
+	if (err)
+		goto err_unregister_notifier;
 
 	return 0;
+
+err_unregister_notifier:
+	unregister_netdevice_notifier(&nh_netdev_notifier);
+err_unregister_pernet:
+	unregister_pernet_subsys(&nexthop_net_ops);
+	return err;
 }
 subsys_initcall(nexthop_init);
-- 
2.25.1