Hi Jacopo,
On Tue, Apr 28, 2020 at 03:40:36PM +0200, Jacopo Mondi wrote:
> On Mon, Apr 27, 2020 at 12:05:48AM +0300, Laurent Pinchart wrote:
> > Hi Jacopo,
> >
> > Thank you for the patch.
> >
>
> [snip]
>
> > > +
> > > +static int imx219_get_selection(struct v4l2_subdev *sd,
> > > + struct v4l2_subdev_pad_config *cfg,
> > > + struct v4l2_subdev_selection *sel)
> > > +{
> > > + struct imx219 *imx219 = to_imx219(sd);
> > > + const struct v4l2_rect *__crop;
> > > +
> > > + if (sel->pad != 0)
> > > + return -EINVAL;
> > > +
> > > + mutex_lock(&imx219->mutex);
> > > +
> > > + switch (sel->target) {
> > > + case V4L2_SEL_TGT_NATIVE_SIZE:
> > > + sel->r.top = 0;
> > > + sel->r.left = 0;
> > > + sel->r.width = IMX219_NATIVE_WIDTH;
> > > + sel->r.height = IMX219_NATIVE_HEIGHT;
> > > + mutex_unlock(&imx219->mutex);
> > > +
> > > + return 0;
> > > +
> > > + case V4L2_SEL_TGT_CROP_DEFAULT:
> > > + sel->r.top = IMX219_PIXEL_ARRAY_TOP;
> > > + sel->r.left = IMX219_PIXEL_ARRAY_LEFT;
> > > + sel->r.width = IMX219_PIXEL_ARRAY_WIDTH;
> > > + sel->r.height = IMX219_PIXEL_ARRAY_HEIGHT;
> > > + mutex_unlock(&imx219->mutex);
> > > +
> > > + return 0;
> > > +
> > > + case V4L2_SEL_TGT_CROP:
> > > + __crop = __imx219_get_pad_crop(imx219, cfg, sel->pad,
> > > + sel->which);
> > > + sel->r = *__crop;
> > > + mutex_unlock(&imx219->mutex);
> >
> > I should have thought about it before, but only this case requires
> > locking. Maybe
>
> I should have thought it better, yes
>
> >
> > __crop = __imx219_get_pad_crop(imx219, cfg, sel->pad,
> > sel->which);
> > mutex_lock(&imx219->mutex);
>
> Actually, retreiveing __crop should be protected too, as the crop
> rectangle is part of the imx219->mode, which is updated by the set_fmt
> operation.
__crop is a pointer, retrieving the pointer doesn't need protection.
Accessing its contents does. No big deal though, it's cheap, as long as
we don't lock for the bounds and default cases.
> I'll wrap the whole case content in a critical session.
>
> > sel->r = *__crop;
> > mutex_unlock(&imx219->mutex);
> >
> > and removing the mutex_lock() at the beginning ?
> >
> > > +
> > > + return 0;
> > > + }
> > > +
> > > + mutex_unlock(&imx219->mutex);
> > > +
> > > + return -EINVAL;
> > > +}
> > > +
> > > static int imx219_start_streaming(struct imx219 *imx219)
> > > {
> > > struct i2c_client *client = v4l2_get_subdevdata(&imx219->sd);
> > > @@ -1152,6 +1248,7 @@ static const struct v4l2_subdev_pad_ops imx219_pad_ops = {
> > > .enum_mbus_code = imx219_enum_mbus_code,
> > > .get_fmt = imx219_get_pad_format,
> > > .set_fmt = imx219_set_pad_format,
> > > + .get_selection = imx219_get_selection,
> > > .enum_frame_size = imx219_enum_frame_size,
> > > };
> > >
--
Regards,
Laurent Pinchart
