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[PATCH] ACPI: processor: Fix function defined but not used warning

Huisong Li posted 1 patch 4 weeks ago 
include/acpi/processor.h | 34 +++-------------------------------
1 file changed, 3 insertions(+), 31 deletions(-)
[PATCH] ACPI: processor: Fix function defined but not used warning
Posted by Huisong Li 4 weeks ago 
If CONFIG_ACPI_PROCESSOR=n and CONFIG_ACPI_PROCESSOR_IDLE=n, we may
encounter some compling warnings as the following link said.
So remove these empty function definition because they are just used
in processor_driver.c and if CONFIG_ACPI_PROCESSOR is selected and
CONFIG_ACPI_PROCESSOR_IDLE also be selected automatically.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202508300519.tZQHY6HA-lkp@intel.com/

Signed-off-by: Huisong Li <lihuisong@huawei.com>
---
 include/acpi/processor.h | 34 +++-------------------------------
 1 file changed, 3 insertions(+), 31 deletions(-)

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 360b673f05e5..a4e1081fd0da 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -417,40 +417,17 @@ static inline void acpi_processor_throttling_init(void) {}
 #endif	/* CONFIG_ACPI_CPU_FREQ_PSS */
 
 /* in processor_idle.c */
-extern struct cpuidle_driver acpi_idle_driver;
 #ifdef CONFIG_ACPI_PROCESSOR_IDLE
+extern struct cpuidle_driver acpi_idle_driver;
 int acpi_processor_power_init(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr);
 int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
 int acpi_processor_hotplug(struct acpi_processor *pr);
 void acpi_processor_register_idle_driver(void);
 void acpi_processor_unregister_idle_driver(void);
-#else
-static inline int acpi_processor_power_init(struct acpi_processor *pr)
-{
-	return -ENODEV;
-}
-
-static inline int acpi_processor_power_exit(struct acpi_processor *pr)
-{
-	return -ENODEV;
-}
-
-static inline int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
-{
-	return -ENODEV;
-}
 
-static inline int acpi_processor_hotplug(struct acpi_processor *pr)
-{
-	return -ENODEV;
-}
-static inline void acpi_processor_register_idle_driver(void)
-{
-}
-static inline void acpi_processor_unregister_idle_driver(void)
-{
-}
+extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
+extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
 #endif /* CONFIG_ACPI_PROCESSOR_IDLE */
 
 /* in processor_thermal.c */
@@ -473,11 +450,6 @@ static inline void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 }
 #endif	/* CONFIG_CPU_FREQ */
 
-#ifdef CONFIG_ACPI_PROCESSOR_IDLE
-extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
-extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
-#endif
-
 void acpi_processor_init_invariance_cppc(void);
 
 #endif
-- 
2.33.0
Re: [PATCH] ACPI: processor: Fix function defined but not used warning
Posted by Rafael J. Wysocki 4 weeks ago 
On Thu, Sep 4, 2025 at 2:11 PM Huisong Li <lihuisong@huawei.com> wrote:
>
> If CONFIG_ACPI_PROCESSOR=n and CONFIG_ACPI_PROCESSOR_IDLE=n, we may
> encounter some compling warnings as the following link said.
> So remove these empty function definition because they are just used
> in processor_driver.c and if CONFIG_ACPI_PROCESSOR is selected and
> CONFIG_ACPI_PROCESSOR_IDLE also be selected automatically.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202508300519.tZQHY6HA-lkp@intel.com/
>
> Signed-off-by: Huisong Li <lihuisong@huawei.com>
> ---
>  include/acpi/processor.h | 34 +++-------------------------------
>  1 file changed, 3 insertions(+), 31 deletions(-)
>
> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
> index 360b673f05e5..a4e1081fd0da 100644
> --- a/include/acpi/processor.h
> +++ b/include/acpi/processor.h
> @@ -417,40 +417,17 @@ static inline void acpi_processor_throttling_init(void) {}
>  #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
>
>  /* in processor_idle.c */
> -extern struct cpuidle_driver acpi_idle_driver;
>  #ifdef CONFIG_ACPI_PROCESSOR_IDLE
> +extern struct cpuidle_driver acpi_idle_driver;

Are the changes above related to the warning?  If not, maybe move them
to a separate patch?

>  int acpi_processor_power_init(struct acpi_processor *pr);
>  int acpi_processor_power_exit(struct acpi_processor *pr);
>  int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
>  int acpi_processor_hotplug(struct acpi_processor *pr);
>  void acpi_processor_register_idle_driver(void);
>  void acpi_processor_unregister_idle_driver(void);
> -#else
> -static inline int acpi_processor_power_init(struct acpi_processor *pr)
> -{
> -       return -ENODEV;
> -}
> -
> -static inline int acpi_processor_power_exit(struct acpi_processor *pr)
> -{
> -       return -ENODEV;
> -}
> -
> -static inline int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
> -{
> -       return -ENODEV;
> -}
>
> -static inline int acpi_processor_hotplug(struct acpi_processor *pr)
> -{
> -       return -ENODEV;
> -}
> -static inline void acpi_processor_register_idle_driver(void)
> -{
> -}
> -static inline void acpi_processor_unregister_idle_driver(void)
> -{
> -}
> +extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
> +extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);

Please remove the "extern" from these declarations.

>  #endif /* CONFIG_ACPI_PROCESSOR_IDLE */
>
>  /* in processor_thermal.c */
> @@ -473,11 +450,6 @@ static inline void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
>  }
>  #endif /* CONFIG_CPU_FREQ */
>
> -#ifdef CONFIG_ACPI_PROCESSOR_IDLE
> -extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
> -extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
> -#endif
> -
>  void acpi_processor_init_invariance_cppc(void);
>
>  #endif
> --
Re: [PATCH] ACPI: processor: Fix function defined but not used warning
Posted by lihuisong (C) 3 weeks, 6 days ago 
在 2025/9/4 23:23, Rafael J. Wysocki 写道:
> On Thu, Sep 4, 2025 at 2:11 PM Huisong Li <lihuisong@huawei.com> wrote:
>> If CONFIG_ACPI_PROCESSOR=n and CONFIG_ACPI_PROCESSOR_IDLE=n, we may
>> encounter some compling warnings as the following link said.
>> So remove these empty function definition because they are just used
>> in processor_driver.c and if CONFIG_ACPI_PROCESSOR is selected and
>> CONFIG_ACPI_PROCESSOR_IDLE also be selected automatically.
>>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202508300519.tZQHY6HA-lkp@intel.com/
>>
>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>> ---
>>   include/acpi/processor.h | 34 +++-------------------------------
>>   1 file changed, 3 insertions(+), 31 deletions(-)
>>
>> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
>> index 360b673f05e5..a4e1081fd0da 100644
>> --- a/include/acpi/processor.h
>> +++ b/include/acpi/processor.h
>> @@ -417,40 +417,17 @@ static inline void acpi_processor_throttling_init(void) {}
>>   #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
>>
>>   /* in processor_idle.c */
>> -extern struct cpuidle_driver acpi_idle_driver;
>>   #ifdef CONFIG_ACPI_PROCESSOR_IDLE
>> +extern struct cpuidle_driver acpi_idle_driver;
> Are the changes above related to the warning?  If not, maybe move them
> to a separate patch?
Ok, will do it in a separate patch.
>
>>   int acpi_processor_power_init(struct acpi_processor *pr);
>>   int acpi_processor_power_exit(struct acpi_processor *pr);
>>   int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
>>   int acpi_processor_hotplug(struct acpi_processor *pr);
>>   void acpi_processor_register_idle_driver(void);
>>   void acpi_processor_unregister_idle_driver(void);
>> -#else
>> -static inline int acpi_processor_power_init(struct acpi_processor *pr)
>> -{
>> -       return -ENODEV;
>> -}
>> -
>> -static inline int acpi_processor_power_exit(struct acpi_processor *pr)
>> -{
>> -       return -ENODEV;
>> -}
>> -
>> -static inline int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
>> -{
>> -       return -ENODEV;
>> -}
>>
>> -static inline int acpi_processor_hotplug(struct acpi_processor *pr)
>> -{
>> -       return -ENODEV;
>> -}
>> -static inline void acpi_processor_register_idle_driver(void)
>> -{
>> -}
>> -static inline void acpi_processor_unregister_idle_driver(void)
>> -{
>> -}
>> +extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
>> +extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
> Please remove the "extern" from these declarations.
Ack
>
>>   #endif /* CONFIG_ACPI_PROCESSOR_IDLE */
>>
>>   /* in processor_thermal.c */
>> @@ -473,11 +450,6 @@ static inline void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
>>   }
>>   #endif /* CONFIG_CPU_FREQ */
>>
>> -#ifdef CONFIG_ACPI_PROCESSOR_IDLE
>> -extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
>> -extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
>> -#endif
>> -
>>   void acpi_processor_init_invariance_cppc(void);
>>
>>   #endif
>> --

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