netdev - Re: [PATCH] net: cls_api: remove unneeded local variable in tc_dump

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Message-ID: <20201030140641.4fbeb575@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net>
Date:   Fri, 30 Oct 2020 14:06:41 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Lukas Bulwahn <lukas.bulwahn@...il.com>
Cc:     Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, clang-built-linux@...glegroups.com,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-safety@...ts.elisa.tech
Subject: Re: [PATCH] net: cls_api: remove unneeded local variable in
 tc_dump_chain()

On Wed, 28 Oct 2020 12:35:33 +0100 Lukas Bulwahn wrote:
> make clang-analyzer on x86_64 defconfig caught my attention with:
> 
> net/sched/cls_api.c:2964:3: warning: Value stored to 'parent' is never read
>   [clang-analyzer-deadcode.DeadStores]
>                 parent = 0;
>                 ^
> 
> net/sched/cls_api.c:2977:4: warning: Value stored to 'parent' is never read
>   [clang-analyzer-deadcode.DeadStores]
>                         parent = q->handle;
>                         ^
> 
> Commit 32a4f5ecd738 ("net: sched: introduce chain object to uapi")
> introduced tc_dump_chain() and this initial implementation already
> contained these unneeded dead stores.
> 
> Simplify the code to make clang-analyzer happy.
> 
> As compilers will detect these unneeded assignments and optimize this
> anyway, the resulting binary is identical before and after this change.
> 
> No functional change. No change in object code.
> 
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@...il.com>
> ---
> applies cleanly on current master and next-20201028
> 
> Jamal, Cong, Jiri, please ack.
> David, Jakub, please pick this minor non-urgent clean-up patch.

Applied, thanks!