Re: [PATCH v6 net-next 13/13] mlx5: support BIG TCP packets

On Fri, May 13, 2022 at 10:04 AM Jakub Kicinski [off-list ref] wrote:

On Fri, 13 May 2022 06:05:36 -0700 Eric Dumazet wrote:

quoted

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.