From 63c6ba4352009a5f85b32307c001abeb5baebd28 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Wed, 15 Aug 2012 22:10:50 +0200
Subject: [PATCH] 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>
---
drivers/cpuidle/coupled.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 2c9bf2692232e..c24dda03c143e 100644
--- 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);