Re: [PATCH v4 3/5] acpi_processor: do not mark present at boot but not onlined CPU as onlined

[Igor Mammedov]

On Tue, 15 Apr 2014 07:48:30 +0200
"Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> wrote:

> On Monday, April 14, 2014 05:11:15 PM Igor Mammedov wrote:
> > acpi_processor_add() assumes that present at boot CPUs
> > are always onlined, it is not so if a CPU failed to become
> > onlined. As result acpi_processor_add() will mark such CPU
> > device as onlined in sysfs and following attempts to
> > online/offline it using /sys/device/system/cpu/cpuX/online
> > attribute will fail.
> > 
> > Do not poke into device internals in acpi_processor_add()
> > and touch "struct device { .offline }" attribute, since
> > for CPUs onlined at boot it's set by:
> >   topology_init() -> arch_register_cpu() -> register_cpu()
> > before ACPI device tree is parsed, and for hotplugged
> > CPUs it's set when userspace onlines CPU via sysfs.
> > 
> > Signed-off-by: Igor Mammedov <imammedo@xxxxxxxxxx>
> > ---
> > v2:
> >  - fix regression in v1 leading to NULL pointer dereference
> >    on CPU unplug, do not remove "pr->dev = dev;"
> 
> Yeah.
> 
> Does this patch depend on any other patches in the series?
> 
> I don't think so, but just asking.
> 
> If it doesn't, why is it part of this series at all?
It's doesn't depend on any other patches in here, it was just
convenient to post it as a part of fixes found in CPU hotplug
code and nothing more.

> 
> > ---
> >  drivers/acpi/acpi_processor.c |    1 -
> >  1 files changed, 0 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> > index c29c2c3..42d66f8 100644
> > --- a/drivers/acpi/acpi_processor.c
> > +++ b/drivers/acpi/acpi_processor.c
> > @@ -404,7 +404,6 @@ static int acpi_processor_add(struct acpi_device *device,
> >  		goto err;
> >  
> >  	pr->dev = dev;
> > -	dev->offline = pr->flags.need_hotplug_init;
> >  
> >  	/* Trigger the processor driver's .probe() if present. */
> >  	if (device_attach(dev) >= 0)
> > 
> 

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