From e06b1b56f9bfcc91e1f175fe8d8bf3e35dafa080 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 24 Mar 2009 14:17:19 -0700 Subject: [PATCH] x86: Correct behaviour of irq affinity Impact: get correct smp_affinity as user requested The effect of setting desc->affinity (ie. from userspace via sysfs) has varied over time. In 2.6.27, the 32-bit code anded the value with cpu_online_map, and both 32 and 64-bit did that anding whenever a cpu was unplugged. 2.6.29 consolidated this into one routine (and fixed hotplug) but introduced another variation: anding the affinity with cfg->domain. We should just set it to what the user said - if possible. (cpu_mask_to_apicid_and already takes cpu_online_mask into account) Signed-off-by: Yinghai Lu Acked-by: "Eric W. Biederman" Cc: Andrew Morton LKML-Reference: <49C94DDF.2010703@kernel.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/io_apic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 1ed6c0600cd..d990408ca06 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -594,9 +594,10 @@ set_desc_affinity(struct irq_desc *desc, const struct cpumask *mask) /* check that before desc->addinity get updated */ set_extra_move_desc(desc, mask); - cpumask_and(desc->affinity, cfg->domain, mask); - return apic->cpu_mask_to_apicid_and(desc->affinity, cpu_online_mask); + cpumask_copy(desc->affinity, mask); + + return apic->cpu_mask_to_apicid_and(desc->affinity, cfg->domain); } static void -- 2.41.1