From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hangbin Liu <liuhangbin@gmail.com>
Subject: Re: [PATCH net] ipv6: no need to return rt->dst.error if it is not
 null entry.
Date: Thu, 20 Jul 2017 23:23:52 +0800
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Cc: Roopa Prabhu <roopa@cumulusnetworks.com>,
        WANG Cong <xiyou.wangcong@gmail.com>,
        Hangbin Liu <liuhangbin@gmail.com>
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2017-07-20 23:06 GMT+08:00 Hangbin Liu <liuhangbin@gmail.com>:
>> +++ b/net/ipv6/route.c
>> @@ -3637,12 +3637,6 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
>>                 dst = ip6_route_lookup(net, &fl6, 0);
>>
>>         rt = container_of(dst, struct rt6_info, dst);
>> -       if (rt->dst.error) {
>> -               err = rt->dst.error;
>> -               ip6_rt_put(rt);
>> -               goto errout;
>> -       }
>
> hmm... or instead of remove this check, should we check all the entry? Like
> if ((rt->dst.error && rt != net->ipv6.ip6_null_entry && rt !=
                                                    ^^ mistake here
> net->ipv6.ip6_blk_hole_entry) ||
>      rt == net->ipv6.ip6_null_entry )

Sorry,  there should be no need to check ip6_null_entry since the
error is already
-ENETUNREACH. So how about

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 4d30c96..c290aa4 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3637,13 +3637,8 @@ static int inet6_rtm_getroute(struct sk_buff
*in_skb, struct nlmsghdr *nlh,
                dst = ip6_route_lookup(net, &fl6, 0);

        rt = container_of(dst, struct rt6_info, dst);
-       if (rt->dst.error) {
-               err = rt->dst.error;
-               ip6_rt_put(rt);
-               goto errout;
-       }
-
-       if (rt == net->ipv6.ip6_null_entry) {
+       if (rt->dst.error && rt != net->ipv6.ip6_prohibit_entry &&
+           rt != net->ipv6.ip6_blk_hole_entry) {
                err = rt->dst.error;
                ip6_rt_put(rt);
                goto errout;

Thanks
Hangbin