genirq: Make sure the initial affinity is not empty

[ Upstream commit bddda606ec76550dd63592e32a6e87e7d32583f7 ]

If all CPUs in the irq_default_affinity mask are offline when an interrupt
is initialized then irq_setup_affinity() can set an empty affinity mask for
a newly allocated interrupt.

Fix this by falling back to cpu_online_mask in case the resulting affinity
mask is zero.

Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-msm@vger.kernel.org
Link: https://lkml.kernel.org/r/1545312957-8504-1-git-send-email-sramana@codeaurora.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 9dbdcca..5c0ba5c 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -393,6 +393,9 @@ int irq_setup_affinity(struct irq_desc *desc)
        }
 
        cpumask_and(&mask, cpu_online_mask, set);
+       if (cpumask_empty(&mask))
+               cpumask_copy(&mask, cpu_online_mask);
+
        if (node != NUMA_NO_NODE) {
                const struct cpumask *nodemask = cpumask_of_node(node);