[PATCH] BRIDGE: Fix faulty check in br_stp_recalculate_bridge_id()

There is a regression in 2.6.15.
One of the conversions from memcmp to compare_ether_addr is incorrect.
We need to do relative comparison to determine min MAC address to
use in bridge id. This will cause the wrong bridge id to be chosen
which violates 802.1d Spanning Tree Protocol, and may create forwarding
loops.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/bridge/br_stp_if.c

@@ -158,7 +158,7 @@ void br_stp_recalculate_bridge_id(struct net_bridge *br)
 
 	list_for_each_entry(p, &br->port_list, list) {
 		if (addr == br_mac_zero ||
-		    compare_ether_addr(p->dev->dev_addr, addr) < 0)
+		    memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 			addr = p->dev->dev_addr;
 
 	}