Re: [PATCH 1/6] cpufreq: Use existing stub functions instead of IS_ENABLED macro

[Daniel Lezcano]

On 22/06/2019 11:12, Rafael J. Wysocki wrote:
> On Fri, Jun 21, 2019 at 3:23 PM Daniel Lezcano
> <daniel.lezcano@xxxxxxxxxx> wrote:
>>
>> The functions stub already exist for the condition the IS_ENABLED
>> is trying to avoid.
>>
>> Remove the IS_ENABLED macros as they are pointless.
> 
> AFAICS, the IS_ENABLED checks are an optimization to avoid generating
> pointless code (including a branch) in case CONFIG_CPU_THERMAL is not
> set.
> 
> Why do you think that it is not useful?

I agree but I'm not a big fan of IS_ENABLED macros in the code when it
is possible to avoid them.

What about adding a stub for that like:

#ifdef CPU_THERMAL
static inline int cpufreq_is_cooling_dev(struct cpufreq_driver *drv)
{
	return drv->flags & CPUFREQ_IS_COOLING_DEV;
}
#else
static inline int cpufreq_is_cooling_dev(struct cpufreq_driver *drv)
{
	return 0;
}
#endif

?

>> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
>> ---
>>  drivers/cpufreq/cpufreq.c | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>> index 85ff958e01f1..7c72f7d3509c 100644
>> --- a/drivers/cpufreq/cpufreq.c
>> +++ b/drivers/cpufreq/cpufreq.c
>> @@ -1378,8 +1378,7 @@ static int cpufreq_online(unsigned int cpu)
>>         if (cpufreq_driver->ready)
>>                 cpufreq_driver->ready(policy);
>>
>> -       if (IS_ENABLED(CONFIG_CPU_THERMAL) &&
>> -           cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV)
>> +       if (cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV)
>>                 policy->cdev = of_cpufreq_cooling_register(policy);
>>
>>         pr_debug("initialization complete\n");
>> @@ -1469,8 +1468,7 @@ static int cpufreq_offline(unsigned int cpu)
>>                 goto unlock;
>>         }
>>
>> -       if (IS_ENABLED(CONFIG_CPU_THERMAL) &&
>> -           cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV) {
>> +       if (cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV) {
>>                 cpufreq_cooling_unregister(policy->cdev);
>>                 policy->cdev = NULL;
>>         }
>> --
>> 2.17.1
>>


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