Linux Ethernet Bridging - Apr 2007 - [Bridge] [PATCH] (6/6) bridge: receive path optimization

From: Stephen Hemminger <shemminger@osdl.org>
Date: Thu, 26 May 2005 11:04:25 -0700
> This improves the bridge local receive path by avoiding going
> through another softirq.  The bridge receive path is already being called 
> from a netif_receive_skb() there is no point in going through another
> receiveq round trip. 
> 
> Recursion is limited because bridge can never be a port of a bridge
> so handle_bridge() always returns.
I applied all 6 patches, but this one in particular I'd like
to comment on.

Remember all of those bridge netfilter stack usage issues
we have a few months ago?  This could edge us back into
those problems again.

This improves the bridge local receive path by avoiding going
through another softirq.  The bridge receive path is already being called 
from a netif_receive_skb() there is no point in going through another
receiveq round trip. 

Recursion is limited because bridge can never be a port of a bridge
so handle_bridge() always returns.

Index: bridge/net/bridge/br_input.c
==================================================================---
bridge.orig/net/bridge/br_input.c
+++ bridge/net/bridge/br_input.c
@@ -26,7 +26,7 @@ static int br_pass_frame_up_finish(struc
 #ifdef CONFIG_NETFILTER_DEBUG
 	skb->nf_debug = 0;
 #endif
-	netif_rx(skb);
+	netif_receive_skb(skb);
 
 	return 0;
 }