From: Will Deacon Date: Fri, 27 Apr 2012 11:56:24 +0000 (+0100) Subject: ARM: 7406/1: hotplug: copy the affinity mask when forcefully migrating IRQs X-Git-Tag: firefly_0821_release~3680^2~2968^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5e7371ded05adfcfcee44a8bc070bfc37979b8f2;p=firefly-linux-kernel-4.4.55.git ARM: 7406/1: hotplug: copy the affinity mask when forcefully migrating IRQs When a CPU is hotplugged off, we migrate any IRQs currently affine to it away and onto another online CPU by calling the irq_set_affinity function of the relevant interrupt controller chip. This function returns either IRQ_SET_MASK_OK or IRQ_SET_MASK_OK_NOCOPY, to indicate whether irq_data.affinity was updated. If we are forcefully migrating an interrupt (because the affinity mask no longer identifies any online CPUs) then we should update the IRQ affinity mask to reflect the new CPU set. Failure to do so can potentially leave /proc/irq/n/smp_affinity identifying only offline CPUs, which may confuse userspace IRQ balancing daemons. This patch updates migrate_one_irq to copy the affinity mask when the interrupt chip returns IRQ_SET_MASK_OK after forcefully changing the affinity of an interrupt. Cc: stable@vger.kernel.org Reported-by: Leif Lindholm Signed-off-by: Will Deacon Signed-off-by: Russell King --- diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 71ccdbfed662..8349d4e97e2b 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -155,10 +155,10 @@ static bool migrate_one_irq(struct irq_desc *desc) } c = irq_data_get_irq_chip(d); - if (c->irq_set_affinity) - c->irq_set_affinity(d, affinity, true); - else + if (!c->irq_set_affinity) pr_debug("IRQ%u: unable to set affinity\n", d->irq); + else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) + cpumask_copy(d->affinity, affinity); return ret; }