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 <ccross@android.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 2c9bf2692232e51a66e5455368d9881383ccfc2f..c24dda03c143eec8845c8162e155c2e0fde16067 100644 (file)
--- 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);