Hi Dan,
On Fri, Nov 03, 2023 at 10:24:40AM +0300, Dan Carpenter wrote:
> On Fri, Nov 03, 2023 at 07:00:01AM +0000, Sakari Ailus wrote:
> > Hi Dan,
> >
> > Thanks for the patch.
> >
> > On Fri, Nov 03, 2023 at 09:34:25AM +0300, Dan Carpenter wrote:
> > > The problem is this line here from subdev_do_ioctl().
> > >
> > > client_cap->capabilities &= ~V4L2_SUBDEV_CLIENT_CAP_STREAMS;
> > >
> > > The "client_cap->capabilities" variable is a u64. The AND operation
> > > is supposed to clear out the V4L2_SUBDEV_CLIENT_CAP_STREAMS flag. But
> > > because it's a 32 bit variable it accidentally clears our the high 32
> > > bits as well.
> > >
> > > Currently we only use BIT(0) and none ofthe upper bits so this doesn't
> > > affect runtime behavior.
> > >
> > > Fixes: f57fa2959244 ("media: v4l2-subdev: Add new ioctl for client capabilities")
> > > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > > ---
> > > include/uapi/linux/v4l2-subdev.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> > > index 4a195b68f28f..21d149969119 100644
> > > --- a/include/uapi/linux/v4l2-subdev.h
> > > +++ b/include/uapi/linux/v4l2-subdev.h
> > > @@ -239,7 +239,7 @@ struct v4l2_subdev_routing {
> > > * set (which is the default), the 'stream' fields will be forced to 0 by the
> > > * kernel.
> > > */
> > > - #define V4L2_SUBDEV_CLIENT_CAP_STREAMS (1U << 0)
> > > + #define V4L2_SUBDEV_CLIENT_CAP_STREAMS BIT_ULL(0)
> >
> > This is a UAPI header but BIT_ULL() is defined in kernel-only headers.
> >
> > So (1ULL << 0) ?
> >
> > uapi/linux/const.h also has _BITULL().
>
> Let's just do 1ULL < 0. I'll resend. Is there an automated way I could
> have caught this?
I don't know. :-) Remember to use shift left for bit definitions in UAPI
headers?
--
Regards,
Sakari Ailus
