From: MaJun <majun258@huawei.com>
Date: Thu, 18 May 2017 16:19:13 +0800
Subject: irqchip/gicv3-its: Skip irq affinity setting when target cpu is the
 same as current setting
Patch-mainline: v4.13-rc1
Git-commit: 8b8d94a72fd4e773320173efbc745ed8fe677ac5
References: FATE#323954

Just skip the irq affinity setting when the target cpu is the same as
current setting.
This is a small optimization for irq affinity setting logic.

Signed-off-by: MaJun <majun258@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
 drivers/irqchip/irq-gic-v3-its.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -644,9 +644,12 @@
 	if (cpu >= nr_cpu_ids)
 		return -EINVAL;
 
-	target_col = &its_dev->its->collections[cpu];
-	its_send_movi(its_dev, target_col, id);
-	its_dev->event_map.col_map[id] = cpu;
+	/* don't set the affinity when the target cpu is same as current one */
+	if (cpu != its_dev->event_map.col_map[id]) {
+		target_col = &its_dev->its->collections[cpu];
+		its_send_movi(its_dev, target_col, id);
+		its_dev->event_map.col_map[id] = cpu;
+	}
 
 	return IRQ_SET_MASK_OK_DONE;
 }