diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index e8c77d3..93a8c34 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -85,6 +85,20 @@
 	struct list_head        policy_list;
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
+
+	/*
+	 * The rules for this semaphore:
+	 * - Any routine that wants to read from the policy structure will
+	 *   do a down_read on this semaphore.
+	 * - Any routine that will write to the policy structure and/or may take away
+	 *   the policy altogether (eg. CPU hotplug), will hold this lock in write
+	 *   mode before doing so.
+	 *
+	 * Additional rules:
+	 * - Lock should not be held across
+	 *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+	 */
+	struct rw_semaphore	rwsem;
 };
 
 /* Only for ACPI */