[RFC PATCH v6 3/3] arm: fix a migrating irq bug when hotplug cpu

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Wed, Oct 21, 2015 at 01:47:49PM +0200, Geert Uytterhoeven wrote:
> On Thu, Sep 24, 2015 at 11:32 AM, Yang Yingliang
> <yangyingliang@huawei.com> wrote:
> > When cpu is disabled, all irqs will be migratged to another cpu.
> > In some cases, a new affinity is different, the old affinity need
> > to be updated and if irq_set_affinity's return value is IRQ_SET_MASK_OK_DONE,
> > the old affinity can not be updated. Fix it by using irq_do_set_affinity.
> >
> > And migrating interrupts is a core code matter, so use the generic
> > function irq_migrate_all_off_this_cpu() to migrate interrupts in
> > kernel/irq/migration.c.
> >
> > Cc: Jiang Liu <jiang.liu@linux.intel.com>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Marc Zyngier <marc.zyngier@arm.com>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
> > Cc: Hanjun Guo <hanjun.guo@linaro.org>
> > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > ---
> >  arch/arm/Kconfig           |  1 +
> >  arch/arm/include/asm/irq.h |  1 -
> >  arch/arm/kernel/irq.c      | 62 ----------------------------------------------
> >  arch/arm/kernel/smp.c      |  2 +-
> >  4 files changed, 2 insertions(+), 64 deletions(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 72ad724..bffba78 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1492,6 +1492,7 @@ config NR_CPUS
> >  config HOTPLUG_CPU
> >         bool "Support for hot-pluggable CPUs"
> >         depends on SMP
> > +       select GENERIC_IRQ_MIGRATION
> 
> This causes the following warnings during s2ram on r8a7791/koelsch
> (dual-core CA15):

Thanks for the report.  I'll see what tonight's boot run says for my
platforms.  Hopefully, the author of these changes can help debug
this.

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