[PATCH] genirq: Make sure the affinity to be set is not empty

[Srinivas Ramana]

If the default_affinity is managed/initialized by a system and
all the cpus present in irq_default_affinity are hotplugged out
we may end up passing a cpumask of 0 to irq_do_set_affinity().

Fix this by falling back to cpu_online_mask in case the
calculated affinity becomes zero.

Signed-off-by: Srinivas Ramana <sramana@xxxxxxxxxxxxxx>
---
 kernel/irq/manage.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 9dbdccab3b6a..5c0ba5ca5930 100644
--- 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);
 
-- 
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