cpuidle: coupled: fix sleeping while atomic in cpu notifier

The cpu hotplug notifier gets called in both atomic and non-atomic contexts, it is not always safe to lock a mutex. Filter out all events except the six necessary ones, which are all sleepable, before taking the mutex. Signed-off-by: Colin Cross <[email protected]> Reviewed-by: Srivatsa S. Bhat <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>
jadonk · Aug 17, 2012 · 63c6ba4 · 63c6ba4
1 parent 55d7ec4
commit 63c6ba4
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
@@ -678,6 +678,18 @@ static int cpuidle_coupled_cpu_notify(struct notifier_block *nb,
 	int cpu = (unsigned long)hcpu;
 	struct cpuidle_device *dev;
 
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_UP_PREPARE:
+	case CPU_DOWN_PREPARE:
+	case CPU_ONLINE:
+	case CPU_DEAD:
+	case CPU_UP_CANCELED:
+	case CPU_DOWN_FAILED:
+		break;
+	default:
+		return NOTIFY_OK;
+	}
+
 	mutex_lock(&cpuidle_lock);
 
 	dev = per_cpu(cpuidle_devices, cpu);