linux/kernel/irq
Thomas Gleixner 8397913303 genirq/cpuhotplug: Revert "Set force affinity flag on hotplug migration"
That commit was part of the changes moving x86 to the generic CPU hotplug
interrupt migration code. The force flag was required on x86 before the
hierarchical irqdomain rework, but invoking set_affinity() with force=true
stayed and had no side effects.

At some point in the past, the force flag got repurposed to support the
exynos timer interrupt affinity setting to a not yet online CPU, so the
interrupt controller callback does not verify the supplied affinity mask
against cpu_online_mask.

Setting the flag in the CPU hotplug code causes the cpu online masking to
be blocked on these irq controllers and results in potentially affining an
interrupt to the CPU which is unplugged, i.e. instead of moving it away,
it's just reassigned to it.

As the force flags is not longer needed on x86, it's safe to revert that
patch so the ARM irqchips which use the force flag work again.

Add comments to that effect, so this won't happen again.

Note: The online mask handling should be done in the generic code and the
force flag and the masking in the irq chips removed all together, but
that's not a change possible for 4.13. 

Fixes: 77f85e66aa ("genirq/cpuhotplug: Set force affinity flag on hotplug migration")
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1707271217590.3109@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-07-27 15:40:02 +02:00
..
Kconfig genirq/timings: Add infrastructure to track the interrupt timings 2017-06-24 11:44:11 +02:00
Makefile genirq/timings: Add infrastructure to track the interrupt timings 2017-06-24 11:44:11 +02:00
affinity.c pci-v4.13-changes 2017-07-08 15:51:57 -07:00
autoprobe.c genirq: Add force argument to irq_startup() 2017-06-22 18:21:24 +02:00
chip.c genirq/PM: Properly pretend disabled state when force resuming interrupts 2017-07-17 22:32:20 +02:00
cpuhotplug.c genirq/cpuhotplug: Revert "Set force affinity flag on hotplug migration" 2017-07-27 15:40:02 +02:00
debug.h irq: hide debug macros so they don't collide with others. 2012-04-23 12:30:03 -04:00
debugfs.c genirq/debugfs: Remove pointless NULL pointer check 2017-06-24 11:43:53 +02:00
devres.c irq/generic-chip: Provide devm_irq_setup_generic_chip() 2017-06-21 15:53:11 +02:00
dummychip.c Merge branch 'linus' into irq/core 2015-06-05 22:25:01 +02:00
generic-chip.c irq/generic-chip: Export irq_init_generic_chip() locally 2017-06-21 15:53:11 +02:00
handle.c There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00
internals.h genirq/PM: Properly pretend disabled state when force resuming interrupts 2017-07-17 22:32:20 +02:00
ipi.c genirq: Fix missing irq allocation affinity hint 2016-07-19 10:49:47 +02:00
irqdesc.c Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-09 10:24:46 -07:00
irqdomain.c irqdomain: Allow ACPI device nodes to be used as irqdomain identifiers 2017-07-07 12:13:29 +02:00
manage.c genirq: Keep chip buslock across irq_request/release_resources() 2017-07-12 10:14:42 +02:00
migration.c genirq: Provide irq_fixup_move_pending() 2017-06-22 18:21:13 +02:00
msi.c genirq/irqdomain: Remove auto-recursive hierarchy support 2017-06-22 18:29:34 +02:00
pm.c genirq/PM: Properly pretend disabled state when force resuming interrupts 2017-07-17 22:32:20 +02:00
proc.c genirq: Introduce effective affinity mask 2017-06-22 18:21:20 +02:00
resend.c genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
settings.h genirq: Add flag to force mask in disable_irq[_nosync]() 2015-10-11 11:33:42 +02:00
spurious.c genirq: Clarify logic calculating bogus irqreturn_t values 2017-02-16 15:32:19 +01:00
timings.c genirq/timings: Add infrastructure for estimating the next interrupt arrival time 2017-06-24 11:44:39 +02:00