From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc:     Yihao Han <hanyihao@vivo.com>, 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>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>, kernel@vivo.com
Subject: Re: [PATCH v2] samples/bpf: xdpsock: fix swap.cocci warning
In-Reply-To: <CAEf4BzYv3ONhy-JnQUtknzgBSK0gpm9GBJYtbAiJQe50_eX7Uw@mail.gmail.com>
References: <20211209092250.56430-1-hanyihao@vivo.com>
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 <CAEf4Bza3a88pdhFEQdR-FnT_gBPqBh+KL-OP-1P3bVfXv=Gbaw@mail.gmail.com>
 <87sfuzuia3.fsf@toke.dk>
 <CAEf4BzYv3ONhy-JnQUtknzgBSK0gpm9GBJYtbAiJQe50_eX7Uw@mail.gmail.com>
Date:   Mon, 13 Dec 2021 13:09:35 +0100
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Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:

> On Sat, Dec 11, 2021 at 10:07 AM Toke H=C3=B8iland-J=C3=B8rgensen <toke@r=
edhat.com> wrote:
>>
>> Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
>>
>> > On Fri, Dec 10, 2021 at 6:26 AM Toke H=C3=B8iland-J=C3=B8rgensen <toke=
@redhat.com> wrote:
>> >>
>> >> Yihao Han <hanyihao@vivo.com> writes:
>> >>
>> >> > Fix following swap.cocci warning:
>> >> > ./samples/bpf/xdpsock_user.c:528:22-23:
>> >> > WARNING opportunity for swap()
>> >> >
>> >> > Signed-off-by: Yihao Han <hanyihao@vivo.com>
>> >>
>> >> Erm, did this get applied without anyone actually trying to compile
>> >> samples? I'm getting build errors as:
>> >
>> > Good news: I actually do build samples/bpf nowadays after fixing a
>> > bunch of compilation issues recently.
>>
>> Awesome!
>>
>> > Bad news: seems like I didn't pay too much attention after building
>> > samples/bpf for this particular patch, sorry about that. I've dropped
>> > this patch, samples/bpf builds for me. We should be good now.
>>
>> Yup, looks good, thanks!
>>
>> >>   CC  /home/build/linux/samples/bpf/xsk_fwd.o
>> >> /home/build/linux/samples/bpf/xsk_fwd.c: In function =E2=80=98swap_ma=
c_addresses=E2=80=99:
>> >> /home/build/linux/samples/bpf/xsk_fwd.c:658:9: warning: implicit decl=
aration of function =E2=80=98swap=E2=80=99; did you mean =E2=80=98swab=E2=
=80=99? [-Wimplicit-function-declaration]
>> >>   658 |         swap(*src_addr, *dst_addr);
>> >>       |         ^~~~
>> >>       |         swab
>> >>
>> >> /usr/bin/ld: /home/build/linux/samples/bpf/xsk_fwd.o: in function `th=
read_func':
>> >> xsk_fwd.c:(.text+0x440): undefined reference to `swap'
>> >> collect2: error: ld returned 1 exit status
>> >>
>> >>
>> >> Could we maybe get samples/bpf added to the BPF CI builds? :)
>> >
>> > Maybe we could, if someone dedicated their effort towards making this
>> > happen.
>>
>> Is it documented anywhere what that would entail? Is it just a matter of
>> submitting a change to https://github.com/kernel-patches/vmtest ?
>
> I think the right way would be to build samples/bpf from
> selftests/bpf's Makefile. At the very least we should not require make
> headers_install (I never understood that with samples/bpf, all those
> up-to-date UAPI headers are right there in the same repo). Once that
> is done, at the very least we'll build tests samples/bpf during CI
> runs.

Alright, sounds fair. I'll look into that, but probably before the
holidays :)

-Toke