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References: <20230613-so-reuseport-v3-2-907b4cbb7b99@isovalent.com> <20230626173249.57682-1-kuniyu@amazon.com>
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From:   Lorenz Bauer <lmb@isovalent.com>
Date:   Tue, 27 Jun 2023 09:56:42 +0100
Message-ID: <CAN+4W8hnPzhuKPorSjHeOQHFgAuk=A9oa1hW5jckUPoF=5zEQQ@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3 2/7] net: export inet_lookup_reuseport and inet6_lookup_reuseport
To:     Kuniyuki Iwashima <kuniyu@amazon.com>
Cc:     andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        daniel@iogearbox.net, davem@davemloft.net, dsahern@kernel.org,
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        kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, martin.lau@linux.dev,
        mykolal@fb.com, netdev@vger.kernel.org, pabeni@redhat.com,
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On Mon, Jun 26, 2023 at 6:33=E2=80=AFPM Kuniyuki Iwashima <kuniyu@amazon.co=
m> wrote:
>
> From: Lorenz Bauer <lmb@isovalent.com>
> Date: Mon, 26 Jun 2023 16:08:59 +0100
> > Rename the existing reuseport helpers for IPv4 and IPv6 so that they
> > can be invoked in the follow up commit. Export them so that DCCP which
> > may be built as a module can access them.
>
> We need not export the functions unless there is a real user.
>
> I added a deprecation notice for DCCP recently, so I bet DCCP
> will not get SO_REUSEPORT support.
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=
=3Db144fcaf46d4

Misleading commit message, it turns out that ipv6 as a module also
needs (the v6 functions at least) to be EXPORT_SYMBOL'd. That's
because of some special shenanigans where inet6_hashtables.c is linked
into vmlinux even when CONFIG_IPV6=3Dm.

Also not sure how to work around this: DCCP may be deprecated but
without the export a module build of it fails.