Re: [PATCH 2/2] media: v4l2-async: Safely unregister an non-registered async subdev

[Sakari Ailus]

Hi Laurent,

On Sat, Feb 27, 2021 at 12:49:38AM +0200, Laurent Pinchart wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> 
> Make the V4L2 async framework a bit more robust by allowing to
> unregister a non-registered async subdev. Otherwise the
> v4l2_async_cleanup() will attempt to delete the async subdev from the
> subdev_list with the corresponding list_head not initialized.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>

Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>

IMO this can be merged through another tree once the first patch is agreed
on. Cc Hans and Mauro, too.

> ---
>  drivers/media/v4l2-core/v4l2-async.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 37cc0263b273..2347b7ac54d4 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -750,6 +750,9 @@ EXPORT_SYMBOL(v4l2_async_register_subdev);
>  
>  void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
>  {
> +	if (list_is_null(&sd->async_list))
> +		return;
> +
>  	mutex_lock(&list_lock);
>  
>  	__v4l2_async_notifier_unregister(sd->subdev_notifier);

-- 
Kind regards,

Sakari Ailus