On Fri, Feb 08, 2019 at 09:49:23AM +0100, Hans Verkuil wrote:
> The sd argument of this macro can be a more complex expression. Since it
> is used 5 times in the macro it can be evaluated that many times as well.
>
> So assign it to a temp variable in the beginning and use that instead.
>
> This also avoids any potential side-effects of evaluating sd.
>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Nice one!
Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
I wonder if this addresses some of the sparse issues related to using a
macro to come up with sd?
> ---
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 47af609dc8f1..34da094a3f40 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -1093,13 +1093,14 @@ void v4l2_subdev_init(struct v4l2_subdev *sd,
> */
> #define v4l2_subdev_call(sd, o, f, args...) \
> ({ \
> + struct v4l2_subdev *__sd = (sd); \
> int __result; \
> - if (!(sd)) \
> + if (!__sd) \
> __result = -ENODEV; \
> - else if (!((sd)->ops->o && (sd)->ops->o->f)) \
> + else if (!(__sd->ops->o && __sd->ops->o->f)) \
> __result = -ENOIOCTLCMD; \
> else \
> - __result = (sd)->ops->o->f((sd), ##args); \
> + __result = __sd->ops->o->f(__sd, ##args); \
> __result; \
> })
>
--
Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
