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Subject: Re: [PATCH v7 03/16] ACPI: processor: Drop duplicated check on _STA
 (enabled + present)
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>, Thomas Gleixner
	<tglx@linutronix.de>, Peter Zijlstra <peterz@infradead.org>,
	<linux-pm@vger.kernel.org>, <loongarch@lists.linux.dev>,
	<linux-acpi@vger.kernel.org>, <linux-arch@vger.kernel.org>,
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	<kvmarm@lists.linux.dev>, <x86@kernel.org>, Russell King
	<linux@armlinux.org.uk>, "Rafael J . Wysocki" <rafael@kernel.org>, Miguel
 Luis <miguel.luis@oracle.com>, James Morse <james.morse@arm.com>, Salil Mehta
	<salil.mehta@huawei.com>, Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
CC: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Dave
 Hansen <dave.hansen@linux.intel.com>, <linuxarm@huawei.com>,
	<justin.he@arm.com>, <jianyong.wu@arm.com>
References: <20240418135412.14730-1-Jonathan.Cameron@huawei.com>
 <20240418135412.14730-4-Jonathan.Cameron@huawei.com>
From: Hanjun Guo <guohanjun@huawei.com>
Message-ID: <c13f7424-3a7f-4c3e-3e8d-81e9fcf0caf7@huawei.com>
Date: Tue, 23 Apr 2024 14:49:13 +0800
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On 2024/4/18 21:53, Jonathan Cameron 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@kernel.org>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.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();

Since the status bits were checked before acpi_processor_add() being
called, do we need to remove the if (!acpi_device_is_enabled(device))
check in acpi_processor_add() as well?

Thanks
Hanjun