From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH net-next] tcp: Check daddr_cache before use in tracepoint
Date: Tue, 17 Oct 2017 10:05:02 -0700
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>
To: David Ahern <dsahern@gmail.com>
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On Tue, Oct 17, 2017 at 8:32 AM, David Ahern <dsahern@gmail.com> wrote:
> On 10/16/17 9:45 PM, Eric Dumazet wrote:
>> IPV6 TCP uses sk->sk_v6_daddr and sk->->sk_v6_rcv_saddr
>
> I moved v2 to those.
>
>> So I would rather remove the need to fetch np = inet6_sk(sk) in the
>> first place, and look at sk->sk_family instead.
>
> I'll spin a v3 with that change.

Note, with CONFIG_IPV6=n, inet6_sk() is just NULL and compiler
could eliminate the if(NULL) branch, I doubt compiler could do same
for sk->sk_family.

Oh, BTW, I thought it is okay to use sk_v6_daddr in if (NULL)
case (aka CONFIG_IPV6=n), but a quick test shows compiler still
complains... so probably need #if IS_ENABLED(CONFIG_IPV6).