linux-kernel - Re: [PATCH v2 3/7] ACPI / processor: Introduce invalid_logical

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Date:	Tue, 05 May 2015 21:15:00 +0800
From:	Hanjun Guo <hanjun.guo@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Sudeep Holla <Sudeep.Holla@....com>,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linaro-acpi@...ts.linaro.org
Subject: Re: [PATCH v2 3/7] ACPI / processor: Introduce invalid_logical_cpuid()

On 2015年05月05日 20:01, Rafael J. Wysocki wrote:
> On Tuesday, May 05, 2015 10:46:34 AM Hanjun Guo wrote:
>> In ACPI processor drivers, we use direct comparisons of cpu logical
>> id with -1 which are error prone in case logical cpuid is accidentally
>> assinged an error code and prevents us from returning an error-encoding
>> cpuid directly in some cases.
>>
>> So introduce invalid_logical_cpuid() to identify cpu with invalid
>> logical cpu num, then it will be used to replace the direct comparisons
>> with -1.
>>
>> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
>> ---
>>   drivers/acpi/acpi_processor.c | 4 ++--
>>   drivers/acpi/processor_pdc.c  | 5 +----
>>   include/linux/acpi.h          | 5 +++++
>>   3 files changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
>> index 95492d0..62c846b 100644
>> --- a/drivers/acpi/acpi_processor.c
>> +++ b/drivers/acpi/acpi_processor.c
>> @@ -274,7 +274,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
>>   		 * Handle UP system running SMP kernel, with no CPU
>>   		 * entry in MADT
>>   		 */
>> -		if ((pr->id == -1) && (num_online_cpus() == 1))
>> +		if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1))
>>   			pr->id = 0;
>>   	}
>>
>> @@ -283,7 +283,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
>>   	 *  less than the max # of CPUs. They should be ignored _iff
>>   	 *  they are physically not present.
>>   	 */
>> -	if (pr->id == -1) {
>> +	if (invalid_logical_cpuid(pr->id)) {
>>   		int ret = acpi_processor_hotadd_init(pr);
>>   		if (ret)
>>   			return ret;
>> diff --git a/drivers/acpi/processor_pdc.c b/drivers/acpi/processor_pdc.c
>> index e5dd808..6dd98d0 100644
>> --- a/drivers/acpi/processor_pdc.c
>> +++ b/drivers/acpi/processor_pdc.c
>> @@ -52,10 +52,7 @@ static bool __init processor_physically_present(acpi_handle handle)
>>   	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
>>   	cpuid = acpi_get_cpuid(handle, type, acpi_id);
>>
>> -	if (cpuid == -1)
>> -		return false;
>> -
>> -	return true;
>> +	return invalid_logical_cpuid(cpuid) ? false : true;
>
> What about
>
> 	return !invalid_logical_cpuid(cpuid);

yes, cleaner, will update my patch.

Thanks
Hanjun
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