[BRIDGE]: forwarding remove unneeded preempt and bh diasables

Optimize the forwarding and transmit paths. Both places are
called with bottom half/no preempt so there is no need to use
spin_lock_bh or rcu_read_lock.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_device.c

@@ -27,6 +27,7 @@ static struct net_device_stats *br_dev_get_stats(struct net_device *dev)
 	return &br->statistics;
 }
 
+/* net device transmit always called with no BH (preempt_disabled) */
 int br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct net_bridge *br = netdev_priv(dev);
@@ -39,7 +40,6 @@ int br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 	skb->mac.raw = skb->data;
 	skb_pull(skb, ETH_HLEN);
 
-	rcu_read_lock();
 	if (dest[0] & 1) 
 		br_flood_deliver(br, skb, 0);
 	else if ((dst = __br_fdb_get(br, dest)) != NULL)
@@ -47,7 +47,6 @@ int br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 	else
 		br_flood_deliver(br, skb, 0);
 
-	rcu_read_unlock();
 	return 0;
 }
 

net/bridge/br_fdb.c

@@ -341,7 +341,6 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 	if (hold_time(br) == 0)
 		return;
 
-	rcu_read_lock();
 	fdb = fdb_find(head, addr);
 	if (likely(fdb)) {
 		/* attempt to update an entry for a local interface */
@@ -356,13 +355,12 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 			fdb->ageing_timer = jiffies;
 		}
 	} else {
-		spin_lock_bh(&br->hash_lock);
+		spin_lock(&br->hash_lock);
 		if (!fdb_find(head, addr))
 			fdb_create(head, source, addr, 0);
 		/* else  we lose race and someone else inserts
 		 * it first, don't bother updating
 		 */
-		spin_unlock_bh(&br->hash_lock);
+		spin_unlock(&br->hash_lock);
 	}
-	rcu_read_unlock();
 }