Re: [PATCH 1/4] v4l: async: fix unbind error in v4l2_async_notifier_unregister()

[Sakari Ailus <sakari.ailus@iki.fi>]

On Mon, Jul 31, 2017 at 12:31:55AM +0200, Niklas Söderlund wrote:
> The call to v4l2_async_cleanup() will set sd->asd to NULL so passing it
> to notifier->unbind() have no effect and leaves the notifier confused.
> Call the unbind() callback prior to cleaning up the subdevice to avoid
> this.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

This is a bugfix and worthy without any other patches and so should be
applied separately.

I think it'd be safer to store sd->asd locally and call the notifier unbind
with that. Now you're making changes to the order in which things work, and
that's not necessary to achieve the objective of passing the async subdev
pointer to the notifier.

With that changed,

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

> ---
>  drivers/media/v4l2-core/v4l2-async.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 851f128eba2219ad..0acf288d7227ba97 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -226,14 +226,14 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
>  
>  		d = get_device(sd->dev);
>  
> +		if (notifier->unbind)
> +			notifier->unbind(notifier, sd, sd->asd);
> +
>  		v4l2_async_cleanup(sd);
>  
>  		/* If we handled USB devices, we'd have to lock the parent too */
>  		device_release_driver(d);
>  
> -		if (notifier->unbind)
> -			notifier->unbind(notifier, sd, sd->asd);
> -
>  		/*
>  		 * Store device at the device cache, in order to call
>  		 * put_device() on the final step
> -- 
> 2.13.3
> 

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi