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From:   Eric Dumazet <edumazet@google.com>
Date:   Fri, 13 May 2022 10:12:54 -0700
Message-ID: <CANn89iJ8XyXLZ1vdTS+vgZsFKsC_BHzi8dMLjfYLKV60rcwatw@mail.gmail.com>
Subject: Re: [PATCH v6 net-next 13/13] mlx5: support BIG TCP packets
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Saeed Mahameed <saeedm@nvidia.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        Alexander Duyck <alexanderduyck@fb.com>,
        Coco Li <lixiaoyan@google.com>,
        Tariq Toukan <tariqt@nvidia.com>,
        Leon Romanovsky <leon@kernel.org>
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On Fri, May 13, 2022 at 10:04 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Fri, 13 May 2022 06:05:36 -0700 Eric Dumazet wrote:
> > The problem is that  skb_cow_head() can fail.
> >
> > Really we have thought about this already.
> >
> > A common helper for drivers is mostly unusable, you would have to
> > pre-allocate a per TX-ring slot to store the headers.
> > We would end up with adding complexity at queue creation/dismantle.
> >
> > We could do that later, because some NICs do not inline the headers in
> > TX descriptor, but instead request
> > one mapped buffer for the headers part only.
> >
> > BTW, I know Tariq already reviewed, the issue at hand is about
> > CONFIG_FORTIFY which is blocking us.
> >
> > This is why I was considering not submitting mlx5 change until Kees
> > Cook and others come up with a solution.
>
> We do have the solution, no?
>
> commit 43213daed6d6 ("fortify: Provide a memcpy trap door for sharp
> corners")

Oh I missed this was already merged.

I will rebase then.

Hopefully ARCH=hexagon|awesome won't trigger a new issue :)

Thanks.