diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 922e8b6fb422316a02aef5157fef3f16455f4286..1ab4f920f1091d925531ecbb6527eac7059c464c 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -323,6 +323,10 @@ struct pernet_operations {
 	 * have to keep in mind all other pernet_operations and
 	 * to introduce a locking, if they share common resources.
 	 *
+	 * The only time they are called with exclusive lock is
+	 * from register_pernet_subsys(), unregister_pernet_subsys()
+	 * register_pernet_device() and unregister_pernet_device().
+	 *
 	 * Exit methods using blocking RCU primitives, such as
 	 * synchronize_rcu(), should be implemented via exit_batch.
 	 * Then, destruction of a group of net requires single
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 9e8ee4640451bc9d12f18064c4efbff9547a6a67..b5796d17a3020513e0b4d087e357b1e747cf4b23 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -43,6 +43,8 @@ static bool init_net_initialized;
 /*
  * pernet_ops_rwsem: protects: pernet_list, net_generic_ids,
  * init_net_initialized and first_device pointer.
+ * This is internal net namespace object. Please, don't use it
+ * outside.
  */
 DECLARE_RWSEM(pernet_ops_rwsem);
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 73011a60434c21ca982014abc48ab01a88b99955..2d3949789cef4148f1325ab5b881201a1b598a26 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -459,7 +459,7 @@ static void rtnl_lock_unregistering_all(void)
  */
 void rtnl_link_unregister(struct rtnl_link_ops *ops)
 {
-	/* Close the race with cleanup_net() */
+	/* Close the race with setup_net() and cleanup_net() */
 	down_write(&pernet_ops_rwsem);
 	rtnl_lock_unregistering_all();
 	__rtnl_link_unregister(ops);