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Subject: Re: [Linux-kernel] [PATCH] net: bpf: add static in net/core/filter.c
From:   Ben Dooks <ben.dooks@codethink.co.uk>
To:     Daniel Borkmann <daniel@iogearbox.net>
Cc:     linux-kernel@lists.codethink.co.uk,
        Song Liu <songliubraving@fb.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        netdev@vger.kernel.org, John Fastabend <john.fastabend@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
        bpf@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        linux-kernel@vger.kernel.org
References: <20191016110446.24622-1-ben.dooks@codethink.co.uk>
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Organization: Codethink Limited.
Message-ID: <16a0fe4a-f63a-7e33-62a2-d3dfbccd8f63@codethink.co.uk>
Date:   Wed, 16 Oct 2019 14:24:39 +0100
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On 16/10/2019 14:11, Ben Dooks wrote:
> On 16/10/2019 14:10, Daniel Borkmann wrote:
>> On Wed, Oct 16, 2019 at 02:02:31PM +0100, Ben Dooks wrote:
>>> On 16/10/2019 13:26, Daniel Borkmann wrote:
>>>> On Wed, Oct 16, 2019 at 12:04:46PM +0100, Ben Dooks (Codethink) wrote:
>>>>> There are a number of structs in net/core/filter.c
>>>>> that are not exported or declared outside of the
>>>>> file. Fix the following warnings by making these
>>>>> all static:
>>>>>
>>>>> net/core/filter.c:8465:31: warning: symbol 'sk_filter_verifier_ops' 
>>>>> was not declared. Should it be static?
>>>>> net/core/filter.c:8472:27: warning: symbol 'sk_filter_prog_ops' was 
>>>>> not declared. Should it be static?
>>>> [...]
>>>>> net/core/filter.c:8935:27: warning: symbol 'sk_reuseport_prog_ops' 
>>>>> was not declared. Should it be static?
>>>>>
>>>>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>>>>> ---
>>>>> Cc: Alexei Starovoitov <ast@kernel.org>
>>>>> Cc: Daniel Borkmann <daniel@iogearbox.net>
>>>>> Cc: Martin KaFai Lau <kafai@fb.com>
>>>>> Cc: Song Liu <songliubraving@fb.com>
>>>>> Cc: Yonghong Song <yhs@fb.com>
>>>>> Cc: "David S. Miller" <davem@davemloft.net>
>>>>> Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
>>>>> Cc: Jesper Dangaard Brouer <hawk@kernel.org>
>>>>> Cc: John Fastabend <john.fastabend@gmail.com>
>>>>> Cc: netdev@vger.kernel.org
>>>>> Cc: bpf@vger.kernel.org
>>>>> Cc: linux-kernel@vger.kernel.org
>>>>> ---
>>>>>    net/core/filter.c | 60 
>>>>> +++++++++++++++++++++++------------------------
>>>>>    1 file changed, 30 insertions(+), 30 deletions(-)
>>>>>
>>>>> diff --git a/net/core/filter.c b/net/core/filter.c
>>>>> index ed6563622ce3..f7338fee41f8 100644
>>>>> --- a/net/core/filter.c
>>>>> +++ b/net/core/filter.c
>>>>> @@ -8462,18 +8462,18 @@ static u32 sk_msg_convert_ctx_access(enum 
>>>>> bpf_access_type type,
>>>>>        return insn - insn_buf;
>>>>>    }
>>>>> -const struct bpf_verifier_ops sk_filter_verifier_ops = {
>>>>> +static const struct bpf_verifier_ops sk_filter_verifier_ops = {
>>>>>        .get_func_proto        = sk_filter_func_proto,
>>>>>        .is_valid_access    = sk_filter_is_valid_access,
>>>>>        .convert_ctx_access    = bpf_convert_ctx_access,
>>>>>        .gen_ld_abs        = bpf_gen_ld_abs,
>>>>>    };
>>>>
>>>> Big obvious NAK. I'm puzzled that you try to fix a compile warning, 
>>>> but without
>>>> even bothering to compile the result after your patch ...
>>>
>>> builds fine. maybe some effort to stop this happening again should be 
>>> made.
>>
>> It doesn't build, because they are used/needed outside:
> 
> Hmm, your config it does, I get /none/ of these warnings.
> 
> I guess a lot of this is being built whether or not is then used.

Without CONFIG_BPF_SYSCALL, a part of net/core/filter.c is being
built but then not declared or used. Should this be split up or
the areas not being built be removed?

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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