X-Git-Url: http://bbs.cooldavid.org/git/?a=blobdiff_plain;f=drivers%2Fcpufreq%2Fcpufreq.c;h=3938c7817095d0747a44045b51cff3c680e6e78a;hb=395913d0b1db37092ea3d9d69b832183b1dd84c5;hp=4da28444b23559e28028cfa2f517993f41071520;hpb=0e625ac153126a0a62b7635fa9dc91f87ff39e38;p=net-next-2.6.git

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 4da28444b23..3938c781709 100644
--- 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;