netdev - Re: [PATCH -next] bpf: remove set but not used variable 'dst

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Message-ID: <F68FB33A-1B98-45C1-8056-457EFA52F84F@fb.com>
Date:   Wed, 15 Apr 2020 07:23:02 +0000
From:   Song Liu <songliubraving@...com>
To:     maowenan <maowenan@...wei.com>
CC:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin Lau <kafai@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andriin@...com>,
        "john.fastabend@...il.com" <john.fastabend@...il.com>,
        "kpsingh@...omium.org" <kpsingh@...omium.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH -next] bpf: remove set but not used variable 'dst_known'



> On Apr 14, 2020, at 6:37 PM, maowenan <maowenan@...wei.com> wrote:
> 
> On 2020/4/15 6:05, Song Liu wrote:
>> 
>> 
>>> On Apr 13, 2020, at 4:37 AM, Mao Wenan <maowenan@...wei.com> wrote:
>>> 
>>> Fixes gcc '-Wunused-but-set-variable' warning:
>>> 
>>> kernel/bpf/verifier.c:5603:18: warning: variable ‘dst_known’
>>> set but not used [-Wunused-but-set-variable]
>>> 
>>> It is not used since commit f1174f77b50c ("bpf/verifier:
>>> rework value tracking")
>> 
>> The fix makes sense. But I think f1174f77b50c introduced dst_known, 
>> so this statement is not accurate. 
>> 
> thanks for review, yes, f1174f77b50c introduced dst_known, and below commit
> doesn't deference variable dst_known. So I send v2 later?
> 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")

I don't think we need to back port this to stable. So it is OK not to 
include Fixes tag. We can just remove this statement in the commit log.

bpf-next is not open yet. Please send v2 when bpf-next is open. 

Thanks,
Song