[PATCH] br: fix race on bridge del if

[Stephen Hemminger <shemminger@xxxxxxxx>]

This fixes the RCU race on bridge delete interface.  Basically,
the network device has to be detached from the bridge in the first
step (pre-RCU), rather than later. At that point, no more bridge traffic
will come in, and the other code will not think that network device
is part of a bridge.

This should also fix the XEN test problems. If there is another
2.6.13-stable, add it as well.

Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxx>

Index: nexgate-test/net/bridge/br_if.c
===================================================================
--- nexgate-test.orig/net/bridge/br_if.c
+++ nexgate-test/net/bridge/br_if.c
@@ -79,7 +79,6 @@ static void destroy_nbp(struct net_bridg
 {
        struct net_device *dev = p->dev;
 
-       dev->br_port = NULL;
        p->br = NULL;
        p->dev = NULL;
        dev_put(dev);
@@ -100,6 +99,7 @@ static void del_nbp(struct net_bridge_po
        struct net_bridge *br = p->br;
        struct net_device *dev = p->dev;
 
+       dev->br_port = NULL;
        dev_set_promiscuity(dev, -1);
 
        spin_lock_bh(&br->lock);