From c48c8b829d2b966a6649827426bcdba082ccf922 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 14 Apr 2022 15:00:11 +0100 Subject: [PATCH] genirq: Take the proposed affinity at face value if force==true Although setting the affinity of an interrupt to a set of CPUs that doesn't have any online CPU is generally frowned apon, there are a few limited cases where such affinity is set from a CPUHP notifier, setting the affinity to a CPU that isn't online yet. The saving grace is that this is always done using the 'force' attribute, which gives a hint that the affinity setting can be outside of the online CPU mask and the callsite set this flag with the knowledge that the underlying interrupt controller knows to handle it. This restores the expected behaviour on Marek's system. Fixes: 33de0aa4bae9 ("genirq: Always limit the affinity to online CPUs") Reported-by: Marek Szyprowski Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Tested-by: Marek Szyprowski Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@samsung.com Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@kernel.org --- kernel/irq/manage.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index f71ecc1..f1d5a94 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -266,10 +266,16 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, prog_mask = mask; } - /* Make sure we only provide online CPUs to the irqchip */ + /* + * Make sure we only provide online CPUs to the irqchip, + * unless we are being asked to force the affinity (in which + * case we do as we are told). + */ cpumask_and(&tmp_mask, prog_mask, cpu_online_mask); - if (!cpumask_empty(&tmp_mask)) + if (!force && !cpumask_empty(&tmp_mask)) ret = chip->irq_set_affinity(data, &tmp_mask, force); + else if (force) + ret = chip->irq_set_affinity(data, mask, force); else ret = -EINVAL; -- 2.7.4