From 35cc2980d9393c16c69dfe5a3f9faddb77eb6811 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Wed, 6 May 2009 17:35:40 -0700
Subject: [PATCH] datapath: Call rcu_barrier() before unloading module.

According to article "RCU and Unloadable Modules" available at lwn.net,
a module that uses RCU callbacks should call rcu_barrier() before
unloading, because synchronize_rcu() does not ensure that all RCU callbacks
have actually completed, only that a grace period has elapsed.
---
 datapath/datapath.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 252e3e00..d3dd6909 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1648,6 +1648,7 @@ error:
 
 static void dp_cleanup(void)
 {
+	rcu_barrier();
 	unregister_chrdev(major, "openvswitch");
 	unregister_netdevice_notifier(&dp_device_notifier);
 	flow_exit();
-- 
2.30.2