linux-kernel - Re: [PATCH v2] sysctl: Remove redundant assignment to first

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Message-ID: <20210510185948.GW4332@42.do-not-panic.com>
Date:   Mon, 10 May 2021 18:59:48 +0000
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     keescook@...omium.org, yzaikin@...gle.com, ast@...nel.org,
        daniel@...earbox.net, andrii@...nel.org, kafai@...com,
        songliubraving@...com, yhs@...com, john.fastabend@...il.com,
        kpsingh@...nel.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Subject: Re: [PATCH v2] sysctl: Remove redundant assignment to first

On Sat, May 08, 2021 at 06:33:10PM +0800, Jiapeng Chong wrote:
> Variable first is set to '0', but this value is never read as it is
> not used later on, hence it is a redundant assignment and can be
> removed.
> 
> Clean up the following clang-analyzer warning:
> 
> kernel/sysctl.c:1562:4: warning: Value stored to 'first' is never read
> [clang-analyzer-deadcode.DeadStores].
> 
> Reported-by: Abaci Robot <abaci@...ux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>

To re-iterate, this does not fix anything, it is just a clean up.

Acked-by: Luis Chamberlain <mcgrof@...nel.org>

  Luis

> ---
> Changes in v2:
>   -For the follow advice: https://lore.kernel.org/patchwork/patch/1422497/
> 
>  kernel/sysctl.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 14edf84..23de0d9 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1474,7 +1474,6 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
>  			 void *buffer, size_t *lenp, loff_t *ppos)
>  {
>  	int err = 0;
> -	bool first = 1;
>  	size_t left = *lenp;
>  	unsigned long bitmap_len = table->maxlen;
>  	unsigned long *bitmap = *(unsigned long **) table->data;
> @@ -1559,12 +1558,12 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
>  			}
>  
>  			bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
> -			first = 0;
>  			proc_skip_char(&p, &left, '\n');
>  		}
>  		left += skipped;
>  	} else {
>  		unsigned long bit_a, bit_b = 0;
> +		bool first = 1;
>  
>  		while (left) {
>  			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
> -- 
> 1.8.3.1
>