From: jbeulich@novell.com
Subject: Module use count must be updated as bridges are created/destroyed
Patch-mainline: unknown
References: 267651

Otherwise 'modprobe -r' on a module having a dependency on bridge will
implicitly unload bridge, bringing down all connectivity that was using
bridges.

---
 net/bridge/br_if.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -291,6 +291,11 @@ int br_add_bridge(struct net *net, const
 	if (!dev)
 		return -ENOMEM;
 
+	if (!try_module_get(THIS_MODULE)) {
+		free_netdev(dev);
+		return -ENOENT;
+	}
+
 	rtnl_lock();
 	if (strchr(dev->name, '%')) {
 		ret = dev_alloc_name(dev, dev->name);
@@ -309,6 +314,8 @@ int br_add_bridge(struct net *net, const
 		unregister_netdevice(dev);
  out:
 	rtnl_unlock();
+	if (ret)
+		module_put(THIS_MODULE);
 	return ret;
 
 out_free:
@@ -340,6 +347,8 @@ int br_del_bridge(struct net *net, const
 		del_br(netdev_priv(dev), NULL);
 
 	rtnl_unlock();
+	if (ret == 0)
+		module_put(THIS_MODULE);
 	return ret;
 }