[PATCH] staging: greybus: Clear up precedence for gcam logging macros

[PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Jackson Chui]

Reported by checkpatch:

CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
precedence issues

Disambiguates '&' (address-of) operator and '->' operator precedence,
accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
'struct device*', which is required by the dev_{dbg,info,err} driver
model diagnostic macros. Issue found by checkpatch.

Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
---
 drivers/staging/greybus/camera.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
index a8173aa3a995..d82a2d2abdca 100644
--- a/drivers/staging/greybus/camera.c
+++ b/drivers/staging/greybus/camera.c
@@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
 
 #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
 
-#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
-#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
-#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
+#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
+#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
+#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
 
 static int gb_camera_operation_sync_flags(struct gb_connection *connection,
 					  int type, unsigned int flags,
-- 
2.34.1

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Alex Elder]

On 4/3/24 7:16 PM, Jackson Chui wrote:
> Reported by checkpatch:
> 
> CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
> precedence issues

I agree with your argument about the way the macro should be
defined.  But perhaps these gcam_*() functions could just
be eliminated?

I see 15 calls to gcam_err(), 1 call to gcam_dbg(), and none
to gcam_info().  It would be a different patch, but maybe
you could do that instead?

					-Alex


> 
> Disambiguates '&' (address-of) operator and '->' operator precedence,
> accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
> 'struct device*', which is required by the dev_{dbg,info,err} driver
> model diagnostic macros. Issue found by checkpatch.
> 
> Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
> ---
>   drivers/staging/greybus/camera.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> index a8173aa3a995..d82a2d2abdca 100644
> --- a/drivers/staging/greybus/camera.c
> +++ b/drivers/staging/greybus/camera.c
> @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
>   
>   #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
>   
> -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
> -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
> -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
> +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
> +#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
> +#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
>   
>   static int gb_camera_operation_sync_flags(struct gb_connection *connection,
>   					  int type, unsigned int flags,

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Jackson Chui]

On Thu, Apr 04, 2024 at 05:05:09PM -0500, Alex Elder wrote:
> On 4/3/24 7:16 PM, Jackson Chui wrote:
> > Reported by checkpatch:
> > 
> > CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
> > precedence issues
> 
> I agree with your argument about the way the macro should be
> defined.  But perhaps these gcam_*() functions could just
> be eliminated?
> 
> I see 15 calls to gcam_err(), 1 call to gcam_dbg(), and none
> to gcam_info().  It would be a different patch, but maybe
> you could do that instead?
> 
> 					-Alex
> 
> 
> > 
> > Disambiguates '&' (address-of) operator and '->' operator precedence,
> > accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
> > 'struct device*', which is required by the dev_{dbg,info,err} driver
> > model diagnostic macros. Issue found by checkpatch.
> > 
> > Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
> > ---
> >   drivers/staging/greybus/camera.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> > index a8173aa3a995..d82a2d2abdca 100644
> > --- a/drivers/staging/greybus/camera.c
> > +++ b/drivers/staging/greybus/camera.c
> > @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
> >   #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
> > -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
> > -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
> > -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
> > +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
> > +#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
> > +#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
> >   static int gb_camera_operation_sync_flags(struct gb_connection *connection,
> >   					  int type, unsigned int flags,
>

Thanks for the feedback, Alex!

I thought about refactoring it, but I feel it is worth keeping
the macro around. It acts as an apdater between callers, who 
have 'gcam' and want to log and what the dynamic debug macros 
expect. Without it, the code gets pretty ugly.

Jackson

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Dan Carpenter]

On Fri, Apr 05, 2024 at 02:22:05PM -0700, Jackson Chui wrote:
> On Thu, Apr 04, 2024 at 05:05:09PM -0500, Alex Elder wrote:
> > On 4/3/24 7:16 PM, Jackson Chui wrote:
> > > Reported by checkpatch:
> > > 
> > > CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
> > > precedence issues
> > 
> > I agree with your argument about the way the macro should be
> > defined.  But perhaps these gcam_*() functions could just
> > be eliminated?
> > 
> > I see 15 calls to gcam_err(), 1 call to gcam_dbg(), and none
> > to gcam_info().  It would be a different patch, but maybe
> > you could do that instead?
> > 
> > 					-Alex
> > 
> > 
> > > 
> > > Disambiguates '&' (address-of) operator and '->' operator precedence,
> > > accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
> > > 'struct device*', which is required by the dev_{dbg,info,err} driver
> > > model diagnostic macros. Issue found by checkpatch.
> > > 
> > > Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
> > > ---
> > >   drivers/staging/greybus/camera.c | 6 +++---
> > >   1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> > > index a8173aa3a995..d82a2d2abdca 100644
> > > --- a/drivers/staging/greybus/camera.c
> > > +++ b/drivers/staging/greybus/camera.c
> > > @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
> > >   #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
> > > -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
> > > -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
> > > -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
> > > +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
> > > +#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
> > > +#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
> > >   static int gb_camera_operation_sync_flags(struct gb_connection *connection,
> > >   					  int type, unsigned int flags,
> >
> 
> Thanks for the feedback, Alex!
> 
> I thought about refactoring it, but I feel it is worth keeping
> the macro around. It acts as an apdater between callers, who 
> have 'gcam' and want to log and what the dynamic debug macros 
> expect. Without it, the code gets pretty ugly.

Another idea would be to create a function:

struct device *gcam_dev(struct gb_camera *gcam)
{
	return &gcam->bundle->dev;
}

	dev_dbg(gcam_dev(gcam), "received metadata ...

(I don't know how to actually compile this code so I haven't tried it).

regards,
dan carpenter

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Alex Elder]

On 4/6/24 4:09 AM, Dan Carpenter wrote:
> On Fri, Apr 05, 2024 at 02:22:05PM -0700, Jackson Chui wrote:
>> On Thu, Apr 04, 2024 at 05:05:09PM -0500, Alex Elder wrote:
>>> On 4/3/24 7:16 PM, Jackson Chui wrote:
>>>> Reported by checkpatch:
>>>>
>>>> CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
>>>> precedence issues
>>>
>>> I agree with your argument about the way the macro should be
>>> defined.  But perhaps these gcam_*() functions could just
>>> be eliminated?
>>>
>>> I see 15 calls to gcam_err(), 1 call to gcam_dbg(), and none
>>> to gcam_info().  It would be a different patch, but maybe
>>> you could do that instead?
>>>
>>> 					-Alex
>>>
>>>
>>>>
>>>> Disambiguates '&' (address-of) operator and '->' operator precedence,
>>>> accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
>>>> 'struct device*', which is required by the dev_{dbg,info,err} driver
>>>> model diagnostic macros. Issue found by checkpatch.
>>>>
>>>> Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
>>>> ---
>>>>    drivers/staging/greybus/camera.c | 6 +++---
>>>>    1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
>>>> index a8173aa3a995..d82a2d2abdca 100644
>>>> --- a/drivers/staging/greybus/camera.c
>>>> +++ b/drivers/staging/greybus/camera.c
>>>> @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
>>>>    #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
>>>> -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
>>>> -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
>>>> -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
>>>> +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
>>>> +#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
>>>> +#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
>>>>    static int gb_camera_operation_sync_flags(struct gb_connection *connection,
>>>>    					  int type, unsigned int flags,
>>>
>>
>> Thanks for the feedback, Alex!
>>
>> I thought about refactoring it, but I feel it is worth keeping
>> the macro around. It acts as an apdater between callers, who
>> have 'gcam' and want to log and what the dynamic debug macros
>> expect. Without it, the code gets pretty ugly.
> 
> Another idea would be to create a function:
> 
> struct device *gcam_dev(struct gb_camera *gcam)
> {
> 	return &gcam->bundle->dev;
> }
> 
> 	dev_dbg(gcam_dev(gcam), "received metadata ...
> 
> (I don't know how to actually compile this code so I haven't tried it).

Yes, I prefer this over the original suggestion.  But
even here the gcam_dev() function doesn't add all that
much value; it saves four characters I guess.

Jackson, the basic principle that makes me say I don't
like the wrapper macros is that the wrapper obscures
the simple call(s) to dev_dbg(), etc.  If there was
something you wanted to do every time--along with
calling dev_dbg()--then maybe the wrapper would be
helpful, but instead it simply hides the standard call.
Better to have the code just use the functions kernel
programmers recognize.

					-Alex
> 
> regards,
> dan carpenter

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Jackson Chui]

On Sat, Apr 06, 2024 at 11:45:51AM -0500, Alex Elder wrote:
> On 4/6/24 4:09 AM, Dan Carpenter wrote:
> > On Fri, Apr 05, 2024 at 02:22:05PM -0700, Jackson Chui wrote:
> > > On Thu, Apr 04, 2024 at 05:05:09PM -0500, Alex Elder wrote:
> > > > On 4/3/24 7:16 PM, Jackson Chui wrote:
> > > > > Reported by checkpatch:
> > > > > 
> > > > > CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
> > > > > precedence issues
> > > > 
> > > > I agree with your argument about the way the macro should be
> > > > defined.  But perhaps these gcam_*() functions could just
> > > > be eliminated?
> > > > 
> > > > I see 15 calls to gcam_err(), 1 call to gcam_dbg(), and none
> > > > to gcam_info().  It would be a different patch, but maybe
> > > > you could do that instead?
> > > > 
> > > > 					-Alex
> > > > 
> > > > 
> > > > > 
> > > > > Disambiguates '&' (address-of) operator and '->' operator precedence,
> > > > > accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
> > > > > 'struct device*', which is required by the dev_{dbg,info,err} driver
> > > > > model diagnostic macros. Issue found by checkpatch.
> > > > > 
> > > > > Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
> > > > > ---
> > > > >    drivers/staging/greybus/camera.c | 6 +++---
> > > > >    1 file changed, 3 insertions(+), 3 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> > > > > index a8173aa3a995..d82a2d2abdca 100644
> > > > > --- a/drivers/staging/greybus/camera.c
> > > > > +++ b/drivers/staging/greybus/camera.c
> > > > > @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
> > > > >    #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
> > > > > -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
> > > > > -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
> > > > > -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
> > > > > +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)
> > > > > +#define gcam_info(gcam, format...)	dev_info(&((gcam)->bundle->dev), format)
> > > > > +#define gcam_err(gcam, format...)	dev_err(&((gcam)->bundle->dev), format)
> > > > >    static int gb_camera_operation_sync_flags(struct gb_connection *connection,
> > > > >    					  int type, unsigned int flags,
> > > > 
> > > 
> > > Thanks for the feedback, Alex!
> > > 
> > > I thought about refactoring it, but I feel it is worth keeping
> > > the macro around. It acts as an apdater between callers, who
> > > have 'gcam' and want to log and what the dynamic debug macros
> > > expect. Without it, the code gets pretty ugly.
> > 
> > Another idea would be to create a function:
> > 
> > struct device *gcam_dev(struct gb_camera *gcam)
> > {
> > 	return &gcam->bundle->dev;
> > }
> > 
> > 	dev_dbg(gcam_dev(gcam), "received metadata ...
> > 
> > (I don't know how to actually compile this code so I haven't tried it).
> 
> Yes, I prefer this over the original suggestion.  But
> even here the gcam_dev() function doesn't add all that
> much value; it saves four characters I guess.
> 
> Jackson, the basic principle that makes me say I don't
> like the wrapper macros is that the wrapper obscures
> the simple call(s) to dev_dbg(), etc.  If there was
> something you wanted to do every time--along with
> calling dev_dbg()--then maybe the wrapper would be
> helpful, but instead it simply hides the standard call.
> Better to have the code just use the functions kernel
> programmers recognize.
> 
> 					-Alex

Dan, Alex I think both of you are spot on.

I like the suggestion of adding 'gcam_dev()' as an accessor
function and directly calling to 'dev_*'. I'm busy this weekend
but will send out a new patch with this change next week.

Jackson

> > 
> > regards,
> > dan carpenter
> 

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Greg Kroah-Hartman]

On Wed, Apr 03, 2024 at 05:16:28PM -0700, Jackson Chui wrote:
> Reported by checkpatch:
> 
> CHECK: Macro argument 'gcam' may be better as '(gcam)' to avoid
> precedence issues
> 
> Disambiguates '&' (address-of) operator and '->' operator precedence,
> accounting for how '(gcam)->bundle->dev' is a 'struct device' and not a
> 'struct device*', which is required by the dev_{dbg,info,err} driver
> model diagnostic macros. Issue found by checkpatch.

This really is not an issue at all, as you are dealing with pointers and
structures and nothing else.

> 
> Signed-off-by: Jackson Chui <jacksonchui.qwerty@gmail.com>
> ---
>  drivers/staging/greybus/camera.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/greybus/camera.c b/drivers/staging/greybus/camera.c
> index a8173aa3a995..d82a2d2abdca 100644
> --- a/drivers/staging/greybus/camera.c
> +++ b/drivers/staging/greybus/camera.c
> @@ -180,9 +180,9 @@ static const struct gb_camera_fmt_info *gb_camera_get_format_info(u16 gb_fmt)
>  
>  #define GB_CAMERA_MAX_SETTINGS_SIZE	8192
>  
> -#define gcam_dbg(gcam, format...)	dev_dbg(&gcam->bundle->dev, format)
> -#define gcam_info(gcam, format...)	dev_info(&gcam->bundle->dev, format)
> -#define gcam_err(gcam, format...)	dev_err(&gcam->bundle->dev, format)
> +#define gcam_dbg(gcam, format...)	dev_dbg(&((gcam)->bundle->dev), format)

Again, the original code here is fine.  Getting rid of the gcam_*()
functions would be nice, as hiding dev_*() calls isn't really needed.

thanks,

greg k-h

Re: [PATCH] staging: greybus: Clear up precedence for gcam logging macros

[Dan Carpenter]

On Sat, Apr 06, 2024 at 06:35:22PM -0400, Jackson Chui wrote:
> > 					-Alex
> 
> Dan, Alex I think both of you are spot on.
> 
> I like the suggestion of adding 'gcam_dev()' as an accessor
> function and directly calling to 'dev_*'. I'm busy this weekend
> but will send out a new patch with this change next week.

Nah, don't bother with adding the gcam_dev() function.  Like Alex says,
it's only 4 characters shorter.  Just get rid of the macros and do:

                dev_err(&gcam->bundle->dev,
                        "Unsupported unsolicited event: %u\n", op->type);

regards,
dan carpenter