[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)

[net-next-2.6.git] / drivers / cpufreq / cpufreq.c

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 4da28444b23559e28028cfa2f517993f41071520..3938c7817095d0747a44045b51cff3c680e6e78a 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -61,6 +61,8 @@ static DEFINE_SPINLOCK(cpufreq_driver_lock);
  *   are concerned with are online after they get the lock.
  * - Governor routines that can be called in cpufreq hotplug path should not
  *   take this sem as top level hotplug notifier handler takes this.
+ * - Lock should not be held across
+ *     __cpufreq_governor(data, CPUFREQ_GOV_STOP);
  */
 static DEFINE_PER_CPU(int, policy_cpu);
 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
@@ -1707,8 +1709,17 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
                        dprintk("governor switch\n");
 
                        /* end old governor */
-                       if (data->governor)
+                       if (data->governor) {
+                               /*
+                                * Need to release the rwsem around governor
+                                * stop due to lock dependency between
+                                * cancel_delayed_work_sync and the read lock
+                                * taken in the delayed work handler.
+                                */
+                               unlock_policy_rwsem_write(data->cpu);
                                __cpufreq_governor(data, CPUFREQ_GOV_STOP);
+                               lock_policy_rwsem_write(data->cpu);
+                       }
 
                        /* start new governor */
                        data->governor = policy->governor;