linux-kernel - Re: [PATCH] hv_balloon: Remove redundant assignment to region

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Message-ID: <20210504125447.wy5e6kar7u5kvc2v@liuwe-devbox-debian-v2>
Date:   Tue, 4 May 2021 12:54:47 +0000
From:   Wei Liu <wei.liu@...nel.org>
To:     Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>
Cc:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        wei.liu@...nel.org, linux-hyperv@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hv_balloon: Remove redundant assignment to region_start

On Thu, Apr 29, 2021 at 06:21:21PM +0800, Jiapeng Chong wrote:
> Variable region_start is set to pg_start but this value is never
> read as it is overwritten later on, hence it is a redundant
> assignment and can be removed.

Indeed. It is overwritten a few lines below.

> 
> Cleans up the following clang-analyzer warning:
> 
> drivers/hv/hv_balloon.c:1013:3: warning: Value stored to 'region_start'
> 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>

Applied to hyperv-next. Thanks.

Wei.

> ---
>  drivers/hv/hv_balloon.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> index 58af84e..7f11ea0 100644
> --- a/drivers/hv/hv_balloon.c
> +++ b/drivers/hv/hv_balloon.c
> @@ -1010,7 +1010,6 @@ static void hot_add_req(struct work_struct *dummy)
>  		 * that need to be hot-added while ensuring the alignment
>  		 * and size requirements of Linux as it relates to hot-add.
>  		 */
> -		region_start = pg_start;
>  		region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
>  		if (pfn_cnt % HA_CHUNK)
>  			region_size += HA_CHUNK;
> -- 
> 1.8.3.1
>