[PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq

[byungchul . park]

From: Byungchul Park <byungchul.park@xxxxxxx>

This patch ensures that the cpu being offlined is not present in the affinity mask.

Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
---
 arch/arm64/kernel/irq.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 473e5db..0c7b79e 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -87,6 +87,7 @@ static bool migrate_one_irq(struct irq_desc *desc)
 {
 	struct irq_data *d = irq_desc_get_irq_data(desc);
 	const struct cpumask *affinity = d->affinity;
+	struct cpumask tmp_affinity;
 	struct irq_chip *c;
 	bool ret = false;
 
@@ -100,6 +101,14 @@ static bool migrate_one_irq(struct irq_desc *desc)
 	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 		affinity = cpu_online_mask;
 		ret = true;
+	} else {
+		/*
+		 * when using forced irq_set_affinity we must ensure that the cpu
+		 * being offlined is not present in the affinity mask, it may be
+		 * selected as the target CPU otherwise
+		 */
+		cpumask_and(&tmp_affinity, affinity, cpu_online_mask);
+		affinity = &tmp_affinity;
 	}
 
 	c = irq_data_get_irq_chip(d);
-- 
1.7.9.5

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