Re: [PATCH] thermal: devfreq_cooling: Fix kernel-doc

From: Nathan Chancellor <nathan@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>,
	Yang Li <yang.lee@linux.alibaba.com>
Cc: Zhang Rui <rui.zhang@intel.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	amitk@kernel.org, linux-pm@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] thermal: devfreq_cooling: Fix kernel-doc
Date: Tue, 8 Jun 2021 11:49:40 -0700	[thread overview]
Message-ID: <6335deba-9e94-61e0-89a1-8905be0e35a1@kernel.org> (raw)
In-Reply-To: <CAKwvOdmyXV09ZxcDqQ6x43f+Eze4h40W2AoKcCmUhGM2gUWsnQ@mail.gmail.com>

On 6/8/2021 11:39 AM, Nick Desaulniers wrote:
> On Tue, Jun 8, 2021 at 2:46 AM Yang Li <yang.lee@linux.alibaba.com> wrote:
>>
>> Fix function name in devfreq_cooling.c kernel-doc comment
>> to remove a warning found by clang(make W=1 LLVM=1).
>>
>> drivers/thermal/devfreq_cooling.c:479: warning: expecting prototype for
>> devfreq_cooling_em_register_power(). Prototype was for
>> devfreq_cooling_em_register() instead.
>>
>> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
>> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
> 
> That compiler warning doesn't come from kernel-doc.  Your diff looks
> good (the comment was wrong), but the commit message is curious.

No, this is indeed kernel-doc complaining. Clang should not even be 
mentioned in the commit message:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kernel-doc?h=v5.13-rc5#n1228

The warning could probably be improved to say "definition" instead of 
"prototype" in certain cases but *shrugs*.

This warning is similar to -Wmissing-prototypes from clang but refers to 
the fact that the comment claims it is documenting one function but it 
is really documenting another.

Cheers,
Nathan

> Usually that warning is from when the function prototype does not
> exist for a function with extern linkage.  It looks like that's always
> provided though in include/linux/devfreq_cooling.h.  Can you share a
> link to the original report?
> 
>> ---
>>   drivers/thermal/devfreq_cooling.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
>> index 3a788ac..5a86cff 100644
>> --- a/drivers/thermal/devfreq_cooling.c
>> +++ b/drivers/thermal/devfreq_cooling.c
>> @@ -458,7 +458,7 @@ struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
>>   EXPORT_SYMBOL_GPL(devfreq_cooling_register);
>>
>>   /**
>> - * devfreq_cooling_em_register_power() - Register devfreq cooling device with
>> + * devfreq_cooling_em_register() - Register devfreq cooling device with
>>    *             power information and automatically register Energy Model (EM)
>>    * @df:                Pointer to devfreq device.
>>    * @dfc_power: Pointer to devfreq_cooling_power.
>> --
>> 1.8.3.1
>>
> 
> 