Re: [PATCH 06/12] parisc: Replace cpu_up/down with device_online/offline

Qais Yousef
2019-11-20T11:09:39Z

On 10/30/19 15:38, Qais Yousef wrote:
> The core device API performs extra housekeeping bits that are missing
> from directly calling cpu_up/down.
>
> See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
> serialization during LPM") for an example description of what might go
> wrong.
>
> This also prepares to make cpu_up/down a private interface for anything
> but the cpu subsystem.
>
> Signed-off-by: Qais Yousef <qais.yousef@arm.com>
> CC: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> CC: Helge Deller <deller@gmx.de>
> CC: Richard Fontana <rfontana@redhat.com>
> CC: Armijn Hemel <armijn@tjaldur.nl>
> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: linux-parisc@vger.kernel.org
> CC: linux-kernel@vger.kernel.org
> ---
>
> Couldn't compile test this one.
>
> I'm not confident that this is a correct patch to be honest. This __init
> indicates we're booting the secondary cpus and that might be too early in the
> process to use the core API..?

Helge, James

Do you have any comment on this? I have no means to test it and I'd
appreciate if you can spin it through one of your systems.

Thanks

--
Qais Yousef

>
>
> arch/parisc/kernel/processor.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/parisc/kernel/processor.c b/arch/parisc/kernel/processor.c
> index 13f771f74ee3..4dde5fe78f0c 100644
> --- a/arch/parisc/kernel/processor.c
> +++ b/arch/parisc/kernel/processor.c
> @@ -212,7 +212,9 @@ static int __init processor_probe(struct parisc_device *dev)
> #ifdef CONFIG_SMP
> if (cpuid) {
> set_cpu_present(cpuid, true);
> - cpu_up(cpuid);
> + lock_device_hotplug();
> + device_online(get_cpu_device(cpuid));
> + unlock_device_hotplug();
> }
> #endif
>
> --
> 2.17.1
>