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From:   Ferenc Fejes <fejes@inf.elte.hu>
Date:   Wed, 3 Jun 2020 10:56:55 +0200
Message-ID: <CAAej5NZZNg+0EbZsa-SrP0S_sOPMqdzgQ9hS8z6DYpQp9G+yhw@mail.gmail.com>
Subject: Re: [PATCH bpf] bpf: fix unused-var without NETDEVICES
To:     Matthieu Baerts <matthieu.baerts@tessares.net>
Cc:     netdev@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andriin@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Matthieu Baerts <matthieu.baerts@tessares.net> ezt =C3=ADrta (id=C5=91pont:
2020. j=C3=BAn. 3., Sze, 10:11):
>
> A recent commit added new variables only used if CONFIG_NETDEVICES is
> set.

Thank you for noticing and fixed this!

> A simple fix is to only declare these variables if the same
> condition is valid.
>
> Other solutions could be to move the code related to SO_BINDTODEVICE
> option from _bpf_setsockopt() function to a dedicated one or only
> declare these variables in the related "case" section.

Yes thats indeed a cleaner way to approach this. I will prepare a fix for t=
hat.

>
> Fixes: 70c58997c1e8 ("bpf: Allow SO_BINDTODEVICE opt in bpf_setsockopt")
> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> ---
>
> Notes:
>     This fix currently applies on net-next and bpf-next only. Except that
>     net-next is now closed and -net will get commits from net-next after
>     Linus' pull.
>
>     I hope it is fine to have picked [PATCH bpf] and not bpf-next (or net=
).
>
>  net/core/filter.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index d01a244b5087..ee08c6fcee1a 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4286,9 +4286,11 @@ static const struct bpf_func_proto bpf_get_socket_=
uid_proto =3D {
>  static int _bpf_setsockopt(struct sock *sk, int level, int optname,
>                            char *optval, int optlen, u32 flags)
>  {
> +#ifdef CONFIG_NETDEVICES
>         char devname[IFNAMSIZ];
>         struct net *net;
>         int ifindex;
> +#endif
>         int ret =3D 0;
>         int val;
>
> --
> 2.25.1
>