ipv6: remove redundant check

err varibale will be set everytime,like -ENOBUFS and in if (err < 0),
 when code gets into this path. This check will just slowdown
the execution and that's all.
Signed-off-by: Xi Huang <xuiagnh@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20240820115442.49366-1-xuiagnh@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv6/addrconf.c

@@ -5619,7 +5619,6 @@ static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa)
 	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFADDR, NULL, GFP_ATOMIC);
 	return;
 errout:
-	if (err < 0)
 	rtnl_set_sk_err(net, RTNLGRP_IPV6_IFADDR, err);
 }
 
@@ -6175,7 +6174,6 @@ void inet6_ifinfo_notify(int event, struct inet6_dev *idev)
 	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_IFINFO, NULL, GFP_ATOMIC);
 	return;
 errout:
-	if (err < 0)
 	rtnl_set_sk_err(net, RTNLGRP_IPV6_IFINFO, err);
 }
 
@@ -6243,7 +6241,6 @@ static void inet6_prefix_notify(int event, struct inet6_dev *idev,
 	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_PREFIX, NULL, GFP_ATOMIC);
 	return;
 errout:
-	if (err < 0)
 	rtnl_set_sk_err(net, RTNLGRP_IPV6_PREFIX, err);
 }