Re: [PATCH AUTOSEL 6.14 20/54] mptcp: move the whole rx path under msk socket lock protection

[Sasha Levin]

On Thu, Apr 10, 2025 at 01:05:11PM +0200, Matthieu Baerts wrote:
> Hi Sasha,
>
> Thank you for having suggested this patch.
>
> On 03/04/2025 21:01, Sasha Levin wrote:
> > From: Paolo Abeni <pabeni@xxxxxxxxxx>
> >
> > [ Upstream commit bc68b0efa1bf923cef1294a631d8e7416c7e06e4 ]
> >
> > After commit c2e6048fa1cf ("mptcp: fix race in release_cb") we can
> > move the whole MPTCP rx path under the socket lock leveraging the
> > release_cb.
> >
> > We can drop a bunch of spin_lock pairs in the receive functions, use
> > a single receive queue and invoke __mptcp_move_skbs only when subflows
> > ask for it.
> >
> > This will allow more cleanup in the next patch.
> >
> > Some changes are worth specific mention:
> >
> > The msk rcvbuf update now always happens under both the msk and the
> > subflow socket lock: we can drop a bunch of ONCE annotation and
> > consolidate the checks.
> >
> > When the skbs move is delayed at msk release callback time, even the
> > msk rcvbuf update is delayed; additionally take care of such action in
> > __mptcp_move_skbs().
> >
> > Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> > Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
> > Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
> > Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-3-4a47d90d7998@xxxxxxxxxx
> > Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> With Mat, we are unsure why this patch has been selected to be
> backported up to v6.6. An AUTOSEL patch has been sent for v6.6, v6.12,
> v6.13 and v6.14. We think it would be better not to backport this patch:
> this is linked to a new feature, and it changes the way the MPTCP socket
> locks are handled.
>
> Could it then please be possible not to queue this patch to the stable
> queues?

I'll drop it, thanks!

--
Thanks,
Sasha