[PATCH V1] media: mc-device.c: change media_device_request_alloc to match media_ioctl_info

[Hans Verkuil]

On 06/08/2020 09:29, frederic.chen at mediatek.com wrote:
> From: Frederic Chen <frederic.chen at mediatek.com>
> 
> We modified the type of media_device_request_alloc()'s second
> parameter from int* to void* so that it can match the interface
> defined in struct media_ioctl_info.
> 
> Signed-off-by: Frederic Chen <frederic.chen at mediatek.com>
> ---
>  drivers/media/mc/mc-device.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
> index da8088351135..bc5b5ecb6581 100644
> --- a/drivers/media/mc/mc-device.c
> +++ b/drivers/media/mc/mc-device.c
> @@ -370,9 +370,10 @@ static long media_device_get_topology(struct media_device *mdev, void *arg)
>  	return ret;
>  }
>  
> -static long media_device_request_alloc(struct media_device *mdev,
> -				       int *alloc_fd)
> +static long media_device_request_alloc(struct media_device *mdev, void *arg)
>  {
> +	int *alloc_fd = arg;
> +
>  #ifdef CONFIG_MEDIA_CONTROLLER_REQUEST_API
>  	if (!mdev->ops || !mdev->ops->req_validate || !mdev->ops->req_queue)
>  		return -ENOTTY;
> 

This change is fine, but the reason this wasn't noticed before is the cast in
the MEDIA_IOC_ARG define:

#define MEDIA_IOC_ARG(__cmd, func, fl, from_user, to_user)              \
        [_IOC_NR(MEDIA_IOC_##__cmd)] = {                                \
                .cmd = MEDIA_IOC_##__cmd,                               \
                .fn = (long (*)(struct media_device *, void *))func,    \
                .flags = fl,                                            \
                .arg_from_user = from_user,                             \
                .arg_to_user = to_user,                                 \
        }

When assigning to .fn the func is cast to a specific function prototype.
Without that cast the compiler would have warned about the mismatch.

I see no reason for that cast, so drop that cast as well.

Regards,

	Hans