linux-kernel - Re: [PATCH v3 7/8] media: uvcvideo: Refactor __uvc_ctrl_add

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Date:   Tue, 3 Jan 2023 22:22:01 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Ricardo Ribalda <ribalda@...omium.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Hans Verkuil <hans.verkuil@...co.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>
Subject: Re: [PATCH v3 7/8] media: uvcvideo: Refactor __uvc_ctrl_add_mapping

Hi Ricardo,

Thank you for the patch.

On Tue, Jan 03, 2023 at 03:36:25PM +0100, Ricardo Ribalda wrote:
> Simplify the exit code with a common error tag freeing all the memory.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> ---
>  drivers/media/usb/uvc/uvc_ctrl.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index aa7a668f60a7..4830120e6506 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -2296,32 +2296,30 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>  	unsigned int i;
>  
>  	/*
> -	 * Most mappings come from static kernel data and need to be duplicated.
> +	 * Most mappings come from static kernel data, and need to be duplicated.
>  	 * Mappings that come from userspace will be unnecessarily duplicated,
>  	 * this could be optimized.
>  	 */
>  	map = kmemdup(mapping, sizeof(*mapping), GFP_KERNEL);
> -	if (map == NULL)
> +	if (!map)
>  		return -ENOMEM;
>  
> +	map->name = NULL;
> +	map->menu_info = NULL;
> +
>  	/* For UVCIOC_CTRL_MAP custom control */
>  	if (mapping->name) {
>  		map->name = kstrdup(mapping->name, GFP_KERNEL);
> -		if (!map->name) {
> -			kfree(map);
> -			return -ENOMEM;
> -		}
> +		if (!map->name)
> +			goto nomem;
>  	}
>  
>  	INIT_LIST_HEAD(&map->ev_subs);
>  
>  	size = sizeof(*mapping->menu_info) * fls(mapping->menu_mask);
>  	map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
> -	if (map->menu_info == NULL) {
> -		kfree(map->name);
> -		kfree(map);
> -		return -ENOMEM;
> -	}
> +	if (!map->menu_info)
> +		goto nomem;
>  
>  	if (map->get == NULL)
>  		map->get = uvc_get_le_value;
> @@ -2342,6 +2340,12 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>  		ctrl->info.selector);
>  
>  	return 0;
> +
> +nomem:

As it's an error label, I'd name it err_nomem. I'll fix that when
applying.

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> +	kfree(map->menu_info);
> +	kfree(map->name);
> +	kfree(map);
> +	return -ENOMEM;
>  }
>  
>  int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> 

-- 
Regards,

Laurent Pinchart