* [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable
@ 2019-02-08 8:49 Hans Verkuil
2019-02-08 9:06 ` Sakari Ailus
0 siblings, 1 reply; 4+ messages in thread
From: Hans Verkuil @ 2019-02-08 8:49 UTC (permalink / raw)
To: Linux Media Mailing List; +Cc: Sakari Ailus, Laurent Pinchart
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@xs4all.nl>
---
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; \
})
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable
2019-02-08 8:49 [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable Hans Verkuil
@ 2019-02-08 9:06 ` Sakari Ailus
2019-02-08 9:08 ` Hans Verkuil
0 siblings, 1 reply; 4+ messages in thread
From: Sakari Ailus @ 2019-02-08 9:06 UTC (permalink / raw)
To: Hans Verkuil; +Cc: Linux Media Mailing List, Laurent Pinchart
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@xs4all.nl>
Nice one!
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
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@linux.intel.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable
2019-02-08 9:06 ` Sakari Ailus
@ 2019-02-08 9:08 ` Hans Verkuil
2019-02-08 10:37 ` Laurent Pinchart
0 siblings, 1 reply; 4+ messages in thread
From: Hans Verkuil @ 2019-02-08 9:08 UTC (permalink / raw)
To: Sakari Ailus; +Cc: Linux Media Mailing List, Laurent Pinchart
On 2/8/19 10:06 AM, Sakari Ailus wrote:
> 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@xs4all.nl>
>
> Nice one!
>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>
> I wonder if this addresses some of the sparse issues related to using a
> macro to come up with sd?
It does solve those as well, in fact :-)
I rejected the omap3/4 patches in favor of this one, which is a much, much
cleaner solution.
Regards,
Hans
>
>> ---
>> 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; \
>> })
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable
2019-02-08 9:08 ` Hans Verkuil
@ 2019-02-08 10:37 ` Laurent Pinchart
0 siblings, 0 replies; 4+ messages in thread
From: Laurent Pinchart @ 2019-02-08 10:37 UTC (permalink / raw)
To: Hans Verkuil; +Cc: Sakari Ailus, Linux Media Mailing List
Hi Hans,
On Fri, Feb 08, 2019 at 10:08:22AM +0100, Hans Verkuil wrote:
> On 2/8/19 10:06 AM, Sakari Ailus wrote:
> > 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@xs4all.nl>
> >
> > Nice one!
> >
> > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> >
> > I wonder if this addresses some of the sparse issues related to using a
> > macro to come up with sd?
>
> It does solve those as well, in fact :-)
>
> I rejected the omap3/4 patches in favor of this one, which is a much, much
> cleaner solution.
Thank you for looking into this. Great work :-)
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >> ---
> >> 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; \
> >> })
> >>
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-02-08 10:37 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-02-08 8:49 [PATCH] v4l2-subdev.h: v4l2_subdev_call: use temp __sd variable Hans Verkuil
2019-02-08 9:06 ` Sakari Ailus
2019-02-08 9:08 ` Hans Verkuil
2019-02-08 10:37 ` Laurent Pinchart
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).