Re: [PATCH-next] fs/btrfs: Fix uninitialized variable

From: David Sterba <dsterba@suse.cz>
To: Khaled ROMDHANI <khaledromdhani216@gmail.com>
Cc: clm@fb.com, josef@toxicpanda.com, dsterba@suse.com,
	linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH-next] fs/btrfs: Fix uninitialized variable
Date: Mon, 26 Apr 2021 22:19:29 +0200	[thread overview]
Message-ID: <20210426201929.GI7604@suse.cz> (raw)
In-Reply-To: <20210423124201.11262-1-khaledromdhani216@gmail.com>

On Fri, Apr 23, 2021 at 01:42:01PM +0100, Khaled ROMDHANI wrote:
> The variable 'zone' is uninitialized which
> introduce some build warning.
> 
> It is not always set or overwritten within
> the function. So explicitly initialize it.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> ---
>  fs/btrfs/zoned.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 432509f4b3ac..42f99b25127f 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -136,7 +136,7 @@ static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zones,
>   */
>  static inline u32 sb_zone_number(int shift, int mirror)
>  {
> -	u64 zone;
> +	u64 zone = 0;

This is exactly same as v1
https://lore.kernel.org/linux-btrfs/20210413130604.11487-1-khaledromdhani216@gmail.com/

It does fix the build warning but does not make sense in the code
because it would would silently let mirror == 4 pass. I think there was
enough feedback under the previous posts how to fix that properly.