Re: [PATCH bpf-next v3 5/8] selftests: bpf: test bpf_skc_to_mptcp_sock

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: Mat Martineau <mathew.j.martineau@linux.intel.com>,
	Networking <netdev@vger.kernel.org>,  bpf <bpf@vger.kernel.org>,
	Geliang Tang <geliang.tang@suse.com>,
	 Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	 Andrii Nakryiko <andrii@kernel.org>,
	mptcp@lists.linux.dev
Subject: Re: [PATCH bpf-next v3 5/8] selftests: bpf: test bpf_skc_to_mptcp_sock
Date: Mon, 9 May 2022 14:00:18 -0700	[thread overview]
Message-ID: <CAEf4BzbwGHtoEooE3wFotgoYi8uDRYJcK=Y0Vdt-JUtWi4rqhg@mail.gmail.com> (raw)
In-Reply-To: <8afe6b33-49c1-5060-87ed-80ef21096bbb@tessares.net>

On Mon, May 9, 2022 at 2:00 AM Matthieu Baerts
<matthieu.baerts@tessares.net> wrote:
>
> Hi Andrii,
>
> Thank you for the review!
>
> On 07/05/2022 00:26, Andrii Nakryiko wrote:
> > On Mon, May 2, 2022 at 2:12 PM Mat Martineau
> > <mathew.j.martineau@linux.intel.com> wrote:
>
> (...)
>
> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> index 359afc617b92..d48d3cb6abbc 100644
> >> --- a/MAINTAINERS
> >> +++ b/MAINTAINERS
> >> @@ -13780,6 +13780,7 @@ F:      include/net/mptcp.h
> >>  F:     include/trace/events/mptcp.h
> >>  F:     include/uapi/linux/mptcp.h
> >>  F:     net/mptcp/
> >> +F:     tools/testing/selftests/bpf/bpf_mptcp_helpers.h
> >>  F:     tools/testing/selftests/bpf/*/*mptcp*.c
> >>  F:     tools/testing/selftests/net/mptcp/
> >>
> >> diff --git a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
> >> new file mode 100644
> >> index 000000000000..18da4cc65e89
> >> --- /dev/null
> >> +++ b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
> >> @@ -0,0 +1,14 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 */
> >> +/* Copyright (c) 2022, SUSE. */
> >> +
> >> +#ifndef __BPF_MPTCP_HELPERS_H
> >> +#define __BPF_MPTCP_HELPERS_H
> >> +
> >> +#include "bpf_tcp_helpers.h"
> >> +
> >> +struct mptcp_sock {
> >> +       struct inet_connection_sock     sk;
> >> +
> >> +} __attribute__((preserve_access_index));
> >
> > why can't all this live in bpf_tcp_helpers.h? why do we need extra header?
>
> The main reason is related to the maintenance: to have MPTCP ML being
> cc'd for all patches modifying this file.
>
> Do you prefer if all these specific MPTCP structures and macros and
> mixed with TCP ones?
>

These definitions don't even have to be 1:1 w/ whatever is kernel
defining in terms of having all the fields, or their order, etc. So I
think it won't require active maintenance and thus can be merged into
bpf_tcp_helpers.h to keep it in one place.

> Cheers,
> Matt
> --
> Tessares | Belgium | Hybrid Access Solutions
> www.tessares.net