From c2f7030a172acb62e93b73c8f59624c56ec9d0f4 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Thu, 13 Oct 2011 22:25:23 +0000
Subject: [PATCH] --- yaml --- r: 266865 b: refs/heads/master c:
 850a545bd8a41648445bfc5541afe36ca105b0b8 h: refs/heads/master i:   266863:
 bbecfcbe64a68f7bc24f03647e9036edbf294117 v: v3

---
 [refs]               | 2 +-
 trunk/net/core/dev.c | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index a1b7c54fa887..4ff21e1e925d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 06a59ecb921de1d44efcf2cdf543bc689fe2e0d8
+refs/heads/master: 850a545bd8a41648445bfc5541afe36ca105b0b8
diff --git a/trunk/net/core/dev.c b/trunk/net/core/dev.c
index cbb5918e4fc5..09aef266d4d1 100644
--- a/trunk/net/core/dev.c
+++ b/trunk/net/core/dev.c
@@ -5235,7 +5235,7 @@ static void rollback_registered_many(struct list_head *head)
 	dev = list_first_entry(head, struct net_device, unreg_list);
 	call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
 
-	rcu_barrier();
+	synchronize_net();
 
 	list_for_each_entry(dev, head, unreg_list)
 		dev_put(dev);
@@ -5748,6 +5748,12 @@ void netdev_run_todo(void)
 
 	__rtnl_unlock();
 
+	/* Wait for rcu callbacks to finish before attempting to drain
+	 * the device list.  This usually avoids a 250ms wait.
+	 */
+	if (!list_empty(&list))
+		rcu_barrier();
+
 	while (!list_empty(&list)) {
 		struct net_device *dev
 			= list_first_entry(&list, struct net_device, todo_list);