From 3f769c7c981af1fa99aa05c960b67aab2f2e6047 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 7 Oct 2008 15:50:03 -0700
Subject: [PATCH] --- yaml --- r: 110235 b: refs/heads/master c:
 58ec3b4db9eb5a28e3aec5f407a54e28f7039c19 h: refs/heads/master i:   110233:
 31730940a97b2d0e4af173b896e7acf1f4fd5aae   110231:
 bf78cb420f19c3a98f23925903a01c495d5f2d97 v: v3

---
 [refs]                     |  2 +-
 trunk/net/core/dev.c       | 27 ++++++---------------------
 trunk/net/core/rtnetlink.c |  2 +-
 3 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/[refs] b/[refs]
index 958ef84f671e..039aed5be3d1 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 742201e7baf66c64995fdd033d706220e6208fab
+refs/heads/master: 58ec3b4db9eb5a28e3aec5f407a54e28f7039c19
diff --git a/trunk/net/core/dev.c b/trunk/net/core/dev.c
index fd992c0f2717..0ae08d3f57e7 100644
--- a/trunk/net/core/dev.c
+++ b/trunk/net/core/dev.c
@@ -3812,14 +3812,11 @@ static int dev_new_index(struct net *net)
 }
 
 /* Delayed registration/unregisteration */
-static DEFINE_SPINLOCK(net_todo_list_lock);
 static LIST_HEAD(net_todo_list);
 
 static void net_set_todo(struct net_device *dev)
 {
-	spin_lock(&net_todo_list_lock);
 	list_add_tail(&dev->todo_list, &net_todo_list);
-	spin_unlock(&net_todo_list_lock);
 }
 
 static void rollback_registered(struct net_device *dev)
@@ -4146,33 +4143,24 @@ static void netdev_wait_allrefs(struct net_device *dev)
  *	free_netdev(y1);
  *	free_netdev(y2);
  *
- * We are invoked by rtnl_unlock() after it drops the semaphore.
+ * We are invoked by rtnl_unlock().
  * This allows us to deal with problems:
  * 1) We can delete sysfs objects which invoke hotplug
  *    without deadlocking with linkwatch via keventd.
  * 2) Since we run with the RTNL semaphore not held, we can sleep
  *    safely in order to wait for the netdev refcnt to drop to zero.
+ *
+ * We must not return until all unregister events added during
+ * the interval the lock was held have been completed.
  */
-static DEFINE_MUTEX(net_todo_run_mutex);
 void netdev_run_todo(void)
 {
 	struct list_head list;
 
-	/* Need to guard against multiple cpu's getting out of order. */
-	mutex_lock(&net_todo_run_mutex);
-
-	/* Not safe to do outside the semaphore.  We must not return
-	 * until all unregister events invoked by the local processor
-	 * have been completed (either by this todo run, or one on
-	 * another cpu).
-	 */
-	if (list_empty(&net_todo_list))
-		goto out;
-
 	/* Snapshot list, allow later requests */
-	spin_lock(&net_todo_list_lock);
 	list_replace_init(&net_todo_list, &list);
-	spin_unlock(&net_todo_list_lock);
+
+	__rtnl_unlock();
 
 	while (!list_empty(&list)) {
 		struct net_device *dev
@@ -4204,9 +4192,6 @@ void netdev_run_todo(void)
 		/* Free network device */
 		kobject_put(&dev->dev.kobj);
 	}
-
-out:
-	mutex_unlock(&net_todo_run_mutex);
 }
 
 static struct net_device_stats *internal_stats(struct net_device *dev)
diff --git a/trunk/net/core/rtnetlink.c b/trunk/net/core/rtnetlink.c
index 71edb8b36341..d6381c2a4693 100644
--- a/trunk/net/core/rtnetlink.c
+++ b/trunk/net/core/rtnetlink.c
@@ -73,7 +73,7 @@ void __rtnl_unlock(void)
 
 void rtnl_unlock(void)
 {
-	mutex_unlock(&rtnl_mutex);
+	/* This fellow will unlock it for us. */
 	netdev_run_todo();
 }