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From:   Yan Zhai <yan@cloudflare.com>
Date:   Tue, 17 Oct 2023 20:41:50 -0500
Message-ID: <CAO3-Pbod3qc7rdg0bN0z5TjeoxO-SAADEwPZm6jcT42Gya8s=g@mail.gmail.com>
Subject: Re: [PATCH v2 net-next] ipv6: avoid atomic fragment on GSO packets
To:     Florian Westphal <fw@strlen.de>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Aya Levin <ayal@nvidia.com>,
        Tariq Toukan <tariqt@nvidia.com>, linux-kernel@vger.kernel.org,
        kernel-team@cloudflare.com,
        Willem de Bruijn <willemdebruijn.kernel@gmail.com>
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On Tue, Oct 17, 2023 at 3:02=E2=80=AFPM Florian Westphal <fw@strlen.de> wro=
te:
>
> Yan Zhai <yan@cloudflare.com> wrote:
> > Refactor __ip6_finish_output code to separate GSO and non-GSO packet
> > processing. It mirrors __ip_finish_output logic now. Add an extra check
> > in GSO handling to avoid atomic fragments. Lastly, drop dst_allfrag
> > check, which is no longer true since commit 9d289715eb5c ("ipv6: stop
> > sending PTB packets for MTU < 1280").
>
>
> > -     if ((skb->len > mtu && !skb_is_gso(skb)) ||
> > -         dst_allfrag(skb_dst(skb)) ||
>
> My preference is to first remove dst_allfrag, i.e. do this in
> a separate change.

You mean completely removing all dst_allfrag references and related
stuff such like IP cork flags/socket flags? I was debating, it might
be cleaner that way but it does not fit so well with the subject of
this patch. I can open a new patchset to clean that up separately. For
this one, I guess I can keep dst_allfrag for now and come back with a
V3. Does that sound good to you?

Yan