Dear Hans,
On Thu, 2020-08-06 at 09:42 +0200, Hans Verkuil wrote:
> On 06/08/2020 09:29, frederic.chen@xxxxxxxxxxxx wrote:
> > From: Frederic Chen <frederic.chen@xxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxx>
> > ---
> > 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.
I got it. I will remove the cast in the next patch.
>
> Regards,
>
> Hans
Sincerely,
Frederic Chen
