Re: [PATCH v7 03/16] ACPI: processor: Drop duplicated check on _STA (enabled + present)

[Hanjun Guo]

On 2024/4/23 17:31, Rafael J. Wysocki wrote:
> On Tue, Apr 23, 2024 at 8:49 AM Hanjun Guo <guohanjun@xxxxxxxxxx> wrote:
> > 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@xxxxxxxxxx>
> > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > >
> > > ---
> > > 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?
>
> No, because its caller only checks the present bit.  The function
> itself checks the enabled bit.

Thanks for the pointer, I can see the detail in the acpi_bus_attach()
now,

Reviewed-by: Hanjun Guo <guohanjun@xxxxxxxxxx>

Thanks
Hanjun