linux-kernel - Re: [PATCH v3 3/3] ACPI: processor: Do not expose the global acpi_idle

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Message-ID: <CAJZ5v0hb19Xy8dOP4itU-F5F7OjDXBVNGYiwoxAVc_yGuUv=Aw@mail.gmail.com>
Date: Wed, 17 Sep 2025 22:01:58 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Huisong Li <lihuisong@...wei.com>
Cc: rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linuxarm@...wei.com, 
	jonathan.cameron@...wei.com, zhanjie9@...ilicon.com, zhenglifeng1@...wei.com, 
	yubowen8@...wei.com
Subject: Re: [PATCH v3 3/3] ACPI: processor: Do not expose the global
 acpi_idle_driver variable

On Thu, Sep 11, 2025 at 1:24 PM Huisong Li <lihuisong@...wei.com> wrote:
>
> Currently, processor_driver just use the global acpi_idle_driver variable
> to check if the cpuidle driver is acpi_idle_driver. Actually, there is no
> need to expose this global variable defined in processor_idle.c to outside.
> So move the related logical to acpi_processor_power_init() and do not
> expose it.

And it can also be made static, can't it?

Please do that too.

> Signed-off-by: Huisong Li <lihuisong@...wei.com>
> ---
>  drivers/acpi/processor_driver.c | 3 +--
>  drivers/acpi/processor_idle.c   | 5 +++++
>  include/acpi/processor.h        | 1 -
>  3 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
> index bc9f58a02c1d..5d824435b26b 100644
> --- a/drivers/acpi/processor_driver.c
> +++ b/drivers/acpi/processor_driver.c
> @@ -166,8 +166,7 @@ static int __acpi_processor_start(struct acpi_device *device)
>         if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
>                 dev_dbg(&device->dev, "CPPC data invalid or not present\n");
>
> -       if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
> -               acpi_processor_power_init(pr);
> +       acpi_processor_power_init(pr);
>
>         acpi_pss_perf_init(pr);
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 5dacf41d7cc0..967fb13f38fa 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -1404,6 +1404,11 @@ int acpi_processor_power_init(struct acpi_processor *pr)
>  {
>         int retval;
>         struct cpuidle_device *dev;
> +       struct cpuidle_driver *drv;
> +
> +       drv = cpuidle_get_driver();
> +       if (drv && drv != &acpi_idle_driver)
> +               return 0;
>
>         if (disabled_by_idle_boot_param())
>                 return 0;
> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
> index 6ee4a69412de..bd96dde5eef5 100644
> --- a/include/acpi/processor.h
> +++ b/include/acpi/processor.h
> @@ -417,7 +417,6 @@ 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
>  int acpi_processor_power_init(struct acpi_processor *pr);
>  int acpi_processor_power_exit(struct acpi_processor *pr);
> --