linux-kernel - Re: [PATCH v3] udf: Use kvzalloc() in udf_sb_alloc

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Date:   Thu, 27 Aug 2020 17:29:25 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Denis Efremov <efremov@...ux.com>, Jan Kara <jack@...e.com>
Cc:     linux-kernel@...r.kernel.org, Joe Perches <joe@...ches.com>
Subject: Re: [PATCH v3] udf: Use kvzalloc() in udf_sb_alloc_bitmap()



On 8/27/20 17:16, Denis Efremov wrote:
> Use kvzalloc() in udf_sb_alloc_bitmap() instead of open-coding it.
> Size computation wrapped in struct_size() macro to prevent potential
> integer overflows.
> 
> Signed-off-by: Denis Efremov <efremov@...ux.com>

Looks good. :)

Reviewed-by: Gustavo A. R. Silva <gustavoars@...nel.org>

Thanks
--
Gustavo

> ---
> Changes in v2:
>  - size computation wrapped in struct_size()
> Changes in v3:
>  - int size dropped
> 
>  fs/udf/super.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index 1c42f544096d..d9eabbe368ff 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -1006,18 +1006,10 @@ int udf_compute_nr_groups(struct super_block *sb, u32 partition)
>  static struct udf_bitmap *udf_sb_alloc_bitmap(struct super_block *sb, u32 index)
>  {
>  	struct udf_bitmap *bitmap;
> -	int nr_groups;
> -	int size;
> -
> -	nr_groups = udf_compute_nr_groups(sb, index);
> -	size = sizeof(struct udf_bitmap) +
> -		(sizeof(struct buffer_head *) * nr_groups);
> -
> -	if (size <= PAGE_SIZE)
> -		bitmap = kzalloc(size, GFP_KERNEL);
> -	else
> -		bitmap = vzalloc(size); /* TODO: get rid of vzalloc */
> +	int nr_groups = udf_compute_nr_groups(sb, index);
>  
> +	bitmap = kvzalloc(struct_size(bitmap, s_block_bitmap, nr_groups),
> +			  GFP_KERNEL);
>  	if (!bitmap)
>  		return NULL;
>  
>