Hi Hans,
On Thu, Oct 05, 2023 at 12:37:41PM +0200, Hans Verkuil wrote:
> On 03/10/2023 14:08, Sakari Ailus wrote:
> > As the user needs to know what went wrong for S_ROUTING, copy array
> > arguments back to the user.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/v4l2-core/v4l2-ioctl.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > index fb453b7d0c91..6921a72566df 100644
> > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > @@ -3419,7 +3419,8 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg,
> > * in case of failure, but it is not defined here as part of the
> > * 'v4l2_ioctls' array, insert an ad-hoc check to address that.
> > */
> > - if (err < 0 && !always_copy && cmd != VIDIOC_SUBDEV_G_ROUTING)
> > + if (err < 0 && !always_copy && cmd != VIDIOC_SUBDEV_G_ROUTING &&
> > + cmd != VIDIOC_SUBDEV_S_ROUTING)
> > goto out;
> >
> > if (has_array_args) {
>
> This is ugly.
>
> How about this:
>
> if (cmd == VIDIOC_SUBDEV_G_ROUTING || cmd == VIDIOC_SUBDEV_S_ROUTING)
> always_copy = true;
>
> if (err < 0 && !always_copy)
> goto out;
>
> The first 'if' can also be a 'switch', I have no preference.
>
> This cmd check can also be done earlier in the function, right after
> the call to video_get_user(). It might be a better place.
[GS]_ROUTING are already handled here (plus the related comment is right
above) so I prefer this location, i.e. exact lines above you suggested.
It's indeed cleaner.
--
Regards,
Sakari Ailus
