Re: [PATCH] drm/mediatek: mtk_drm_drv: switch to use devm_kmemdup_array()

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

On Tue, 2025-08-19 at 17:25 +0800, zhang.enpei@zte.com.cn wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> From: Zhang Enpei <zhang.enpei@zte.com.cn>
> 
> Use devm_kmemdup_array() to avoid multiplication or possible overflows.
> 
> Signed-off-by: Zhang Enpei <zhang.enpei@zte.com.cn>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index d5e6bab36414..e700c0f0a3a2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -1003,7 +1003,8 @@ static int mtk_drm_of_ddp_path_build_one(struct device *dev, enum mtk_crtc_path
>                 return -EINVAL;
>         }
> 
> -       final_ddp_path = devm_kmemdup(dev, temp_path, idx * sizeof(temp_path[0]), GFP_KERNEL);
> +       final_ddp_path = devm_kmemdup_array(dev, temp_path, idx,
> +                                           sizeof(*temp_path), GFP_KERNEL);

idx and sizeof(*temp_path) are so small, it's not necessary to worry overflow.
devm_kmemdup_array() would use built-in multiply, it's also a multiplication.

Regards,
CK

>         if (!final_ddp_path)
>                 return -ENOMEM;
> 
> --
> 2.25.1