linux/include
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
..
acpi More ACPI updates for v4.13-rc1 2017-07-10 15:19:40 -07:00
asm-generic Merge branch 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 11:17:52 -07:00
clocksource
crypto crypto: engine - replace pr_xxx by dev_xxx 2017-06-19 14:19:54 +08:00
drm i915, amd and some core fixes + mediatek color support 2017-07-13 11:26:18 -07:00
dt-bindings Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-07-15 10:59:54 -07:00
keys
kvm
linux genirq/cpuhotplug: Revert "Set force affinity flag on hotplug migration" 2017-07-27 15:40:02 +02:00
math-emu
media main drm pull for v4.13 2017-07-09 18:48:37 -07:00
memory
misc cxl: Export library to support IBM XSL 2017-07-03 23:07:03 +10:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-07-20 16:33:39 -07:00
pcmcia
ras trace, ras: add ARM processor error trace event 2017-06-22 18:22:05 +01:00
rdma IB/cma: Fix reference count leak when no ipv4 addresses are set 2017-07-20 11:24:13 -04:00
rxrpc
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-07-13 14:27:32 -07:00
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
sound ASoC: Updates for v4.13 2017-07-03 19:51:42 +02:00
target iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
trace mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
uapi TTY/Serial fixes for 4.13-rc2 2017-07-22 09:00:24 -07:00
video
xen xen/balloon: don't online new memory initially 2017-07-23 08:13:18 +02:00