linux-kernel - Re: [PATCH v7 03/16] ACPI: processor: Drop duplicated check on

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Message-ID: <CAJZ5v0g9g=W9o8=BNDP+3TEUEN4ByjQU9SJPJepE6eFrcRv2+A@mail.gmail.com>
Date: Mon, 22 Apr 2024 20:48:01 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Peter Zijlstra <peterz@...radead.org>, linux-pm@...r.kernel.org, 
	loongarch@...ts.linux.dev, linux-acpi@...r.kernel.org, 
	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, x86@...nel.org, 
	Russell King <linux@...linux.org.uk>, "Rafael J . Wysocki" <rafael@...nel.org>, 
	Miguel Luis <miguel.luis@...cle.com>, James Morse <james.morse@....com>, 
	Salil Mehta <salil.mehta@...wei.com>, Jean-Philippe Brucker <jean-philippe@...aro.org>, 
	Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, linuxarm@...wei.com, justin.he@....com, 
	jianyong.wu@....com
Subject: Re: [PATCH v7 03/16] ACPI: processor: Drop duplicated check on _STA
 (enabled + present)

On Thu, Apr 18, 2024 at 3:55 PM Jonathan Cameron
<Jonathan.Cameron@...wei.com> wrote:
>
> The ACPI bus scan will only result in acpi_processor_add() being called
> if _STA has already been checked and the result is that the
> processor is enabled and present.  Hence drop this additional check.
>
> Suggested-by: Rafael J. Wysocki <rafael@...nel.org>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

LGTM, so

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
> v7: No change
> v6: New patch to drop this unnecessary code. Now I think we only
>     need to explicitly read STA to print a warning in the ARM64
>     arch_unregister_cpu() path where we want to know if the
>     present bit has been unset as well.
> ---
>  drivers/acpi/acpi_processor.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 7fc924aeeed0..ba0a6f0ac841 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -186,17 +186,11 @@ static void __init acpi_pcc_cpufreq_init(void) {}
>  #ifdef CONFIG_ACPI_HOTPLUG_CPU
>  static int acpi_processor_hotadd_init(struct acpi_processor *pr)
>  {
> -       unsigned long long sta;
> -       acpi_status status;
>         int ret;
>
>         if (invalid_phys_cpuid(pr->phys_id))
>                 return -ENODEV;
>
> -       status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
> -       if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
> -               return -ENODEV;
> -
>         cpu_maps_update_begin();
>         cpus_write_lock();
>
> --