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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Fri, 23 Apr 2021 17:12:44 -0700
Message-ID: <CAADnVQJyX718j1FNEDVYVXv2R4Zgm3xPT1wKr-F_Kwe+Pckgqw@mail.gmail.com>
Subject: Re: [PATCH bpf-next] bpf: Document the pahole release info related to
 libbpf in bpf_devel_QA.rst
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Yonghong Song <yhs@fb.com>, Tiezhu Yang <yangtiezhu@loongson.cn>,
        Jonathan Corbet <corbet@lwn.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>
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On Fri, Apr 23, 2021 at 11:20 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Thu, Apr 22, 2021 at 09:12:19PM -0700, Yonghong Song escreveu:
> >
> >
> > On 4/22/21 6:23 PM, Tiezhu Yang wrote:
> > > pahole starts to use libbpf definitions and APIs since v1.13 after the
> > > commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > > It works well with the git repository because the libbpf submodule will
> > > use "git submodule update --init --recursive" to update.
> > >
> > > Unfortunately, the default github release source code does not contain
> > > libbpf submodule source code and this will cause build issues, the tarball
> > > from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > > github, you can get the source tarball with corresponding libbpf submodule
> > > codes from
> > >
> > > https://fedorapeople.org/~acme/dwarves
> > >
> > > This change documents the above issues to give more information so that
> > > we can get the tarball from the right place, early discussion is here:
> > >
> > > https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/
> > >
> > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> > > ---
> > >   Documentation/bpf/bpf_devel_QA.rst | 13 +++++++++++++
> > >   1 file changed, 13 insertions(+)
> > >
> > > diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
> > > index d05e67e..253496a 100644
> > > --- a/Documentation/bpf/bpf_devel_QA.rst
> > > +++ b/Documentation/bpf/bpf_devel_QA.rst
> > > @@ -449,6 +449,19 @@ from source at
> > >   https://github.com/acmel/dwarves
> > > +pahole starts to use libbpf definitions and APIs since v1.13 after the
> > > +commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > > +It works well with the git repository because the libbpf submodule will
> > > +use "git submodule update --init --recursive" to update.
> > > +
> > > +Unfortunately, the default github release source code does not contain
> > > +libbpf submodule source code and this will cause build issues, the tarball
> > > +from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > > +github, you can get the source tarball with corresponding libbpf submodule
> > > +codes from
> > > +
> > > +https://fedorapeople.org/~acme/dwarves
> > > +
> >
> > Arnaldo, could you take a look at this patch? Thanks!
>
> Sure, he documented it as I expected from a previous interaction about
> this. Would be good to add a paragraph stating how to grab libbpf and
> graft it even on a tarball not containing it tho.
>
> Bonus points if the cmake files gets changed in a way that this gets
> notified to the user in the error message.
>
> But these suggestions can come in another patch, for this I can give my:
>
> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Applied. Thanks everyone.