Received-SPF: pass (google.com: domain of linux-ext4+bounces-1226-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Date: Tue, 13 Feb 2024 17:15:08 +0100
From: Jan Kara <jack@suse.cz>
To: Baokun Li <libaokun1@huawei.com>
Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca,
	jack@suse.cz, ritesh.list@gmail.com, linux-kernel@vger.kernel.org,
	yi.zhang@huawei.com, yangerkun@huawei.com, chengzhihao1@huawei.com,
	yukuai3@huawei.com, stable@kernel.org
Subject: Re: [PATCH 6/7] ext4: set type of ac_groups_linear_remaining to
 __u32 to avoid overflow
Message-ID: <20240213161508.ytowat2xixkd45de@quack3>
References: <20240126085716.1363019-1-libaokun1@huawei.com>
 <20240126085716.1363019-7-libaokun1@huawei.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240126085716.1363019-7-libaokun1@huawei.com>

On Fri 26-01-24 16:57:15, Baokun Li wrote:
> Now ac_groups_linear_remaining is of type __u16 and s_mb_max_linear_groups
> is of type unsigned int, so an overflow occurs when setting a value above
> 65535 through the mb_max_linear_groups sysfs interface. Therefore, the
> type of ac_groups_linear_remaining is set to __u32 to avoid overflow.
> 
> Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
> CC: stable@kernel.org
> Signed-off-by: Baokun Li <libaokun1@huawei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/mballoc.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
> index d7aeb5da7d86..498af2abc5d8 100644
> --- a/fs/ext4/mballoc.h
> +++ b/fs/ext4/mballoc.h
> @@ -194,8 +194,8 @@ struct ext4_allocation_context {
>  
>  	__u32 ac_groups_considered;
>  	__u32 ac_flags;		/* allocation hints */
> +	__u32 ac_groups_linear_remaining;
>  	__u16 ac_groups_scanned;
> -	__u16 ac_groups_linear_remaining;
>  	__u16 ac_found;
>  	__u16 ac_cX_found[EXT4_MB_NUM_CRS];
>  	__u16 ac_tail;
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR