[PATCH] ARM: perf: ensure the cpu is available to scheduler when set irq affinity

[roy.qing.li@gmail.com]

From: Li RongQing <roy.qing.li@gmail.com> 

when there are 4 cpus, but only one is available to schedule, the warning
will be generated when run the below command:
    # perf record -g -e cpu-clock -- find / -name "*.ko"
    CPU PMU: unable to set irq affinity (irq=28, cpu=1)
    CPU PMU: unable to set irq affinity (irq=29, cpu=2)
    CPU PMU: unable to set irq affinity (irq=30, cpu=3)

so ensure the cpu is available to scheduler when set irq affinity

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
---
 drivers/perf/arm_pmu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 2365a32..9401aa8 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -619,6 +619,9 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
 			if (cpu_pmu->irq_affinity)
 				cpu = cpu_pmu->irq_affinity[i];
 
+			if (!cpu_online(cpu))
+				continue;
+
 			if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
 				continue;
 			irq = platform_get_irq(pmu_device, i);
@@ -665,6 +668,9 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 			if (cpu_pmu->irq_affinity)
 				cpu = cpu_pmu->irq_affinity[i];
 
+			if (!cpu_online(cpu))
+				continue;
+
 			/*
 			 * If we have a single PMU interrupt that we can't shift,
 			 * assume that we're running on a uniprocessor machine and
-- 
2.1.4