linux-kernel - Re: [PATCH] btrfs: Remove redundant assignment to ret

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Date:   Mon, 10 May 2021 15:41:02 +0200
From:   David Sterba <dsterba@...e.cz>
To:     Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>
Cc:     clm@...com, josef@...icpanda.com, dsterba@...e.com,
        linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] btrfs: Remove redundant assignment to ret

On Sat, May 08, 2021 at 06:38:49PM +0800, Jiapeng Chong wrote:
> Variable ret is set to zero, but this value is never read as it is
> overwritten or not used later on, hence it is a redundant assignment
> and can be removed.
> 
> Clean up the following clang-analyzer warning:
> 
> fs/btrfs/extent_io.c:5357:4: warning: Value stored to 'ret' 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>
> ---
>  fs/btrfs/extent_io.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 074a78a..cea58be 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -5354,7 +5354,6 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
>  				goto out_free;
>  			if (ret)
>  				flags |= FIEMAP_EXTENT_SHARED;
> -			ret = 0;

This leaves the scope where the value of 'ret' has been used for
something and it's reset to 0 for clarity. This is a pattern that we use
and will not change it just to silence clang analyzer.