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

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Message-ID: <20150511163542.GB2942@red-moon>
Date:	Mon, 11 May 2015 17:35:42 +0100
From:	Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:	Hanjun Guo <hanjun.guo@...aro.org>
Cc:	Sudeep Holla <Sudeep.Holla@....com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Will Deacon <Will.Deacon@....com>,
	Catalin Marinas <Catalin.Marinas@....com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linaro-acpi@...ts.linaro.org" <linaro-acpi@...ts.linaro.org>
Subject: Re: [PATCH v2 7/7] ACPI / processor: Introduce invalid_phys_cpuid()

On Tue, May 05, 2015 at 02:14:01PM +0100, Hanjun Guo wrote:
> On 2015???05???05??? 19:25, Sudeep Holla wrote:
> >
> >
> > On 05/05/15 03:46, Hanjun Guo wrote:
> >> Introduce invalid_phys_cpuid() to identify cpu with invalid
> >> physical ID, then used it as replacement of the direct comparisons
> >> with PHYS_CPUID_INVALID.
> >>
> >> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
> >> ---
> >>   drivers/acpi/acpi_processor.c | 4 ++--
> >>   drivers/acpi/processor_core.c | 4 ++--
> >>   include/linux/acpi.h          | 5 +++++
> >>   3 files changed, 9 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/acpi/acpi_processor.c
> >> b/drivers/acpi/acpi_processor.c
> >> index 62c846b..92a5f73 100644
> >> --- a/drivers/acpi/acpi_processor.c
> >
> > [...]
> >
> >> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> >> index 913b49f..cc82ff3 100644
> >> --- a/include/linux/acpi.h
> >> +++ b/include/linux/acpi.h
> >> @@ -163,6 +163,11 @@ static inline bool invalid_logical_cpuid(u32 cpuid)
> >>       return (int)cpuid < 0;
> >>   }
> >>
> >> +static inline bool invalid_phys_cpuid(phys_cpuid_t phys_id)
> >> +{
> >> +    return (int)phys_id < 0;
> >
> > Should this be phys_id == PHYS_CPUID_INVALID ? else I don't see why we
> > need to even define PHYS_CPUID_INVALID
> 
> I'm OK with this. For now, CPU phys_id will be valid value or
> PHYS_CPUID_INVALID in all cases for ACPI processor driver, but
> I want ask Rafael's opinion on this, is it OK to you too, Rafael?

Is your worry related to functions returning error values
other than PHYS_CPUID_INVALID (when they are expected to return a
physical id) ? Is there any in the current kernel ?

static inline bool invalid_phys_cpuid(phys_cpuid_t phys_id)
{
	return phys_id == PHYS_CPUID_INVALID;
}

This should do, and if we need more mapping functions that are supposed
to return physical ids they should return PHYS_CPUID_INVALID on failure.

Lorenzo
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