From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 16 Jan 2012 15:41:47 +0000 Subject: [PATCH] ARM: hotplug: ensure that we copy the affinity mask when migrating IRQs Message-ID: <1326728507-9916-1-git-send-email-will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. In the case of the former, the migration code should update the mask itself, as is done by irq_set_affinity. The current code does not update affinity mask and potentially leaves /proc/irq/n/smp_affinity identifying an offline CPU, which confuses 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 changing the affinity of an interrupt. Reported-by: Leif Lindholm Signed-off-by: Will Deacon --- arch/arm/kernel/irq.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 3efd82c..831435d 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -156,10 +156,10 @@ 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) + cpumask_copy(d->affinity, affinity); return ret; } -- 1.7.4.1