From: Jiri Pirko <jpirko@redhat.com>
Date: Tue, 26 Apr 2011 11:12:04 -0400
Subject: [net] bridge: fix initial packet flood if !STP
Message-id: <1303816324-4941-1-git-send-email-jpirko@redhat.com>
Patchwork-id: 35618
O-Subject: [rhel5 PATCH] net: bridge: fix initial packet flood if !STP
Bugzilla: 695369
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Thomas Graf <tgraf@redhat.com>
RH-Acked-by: David S. Miller <davem@redhat.com>

BZ695369

upstream:
commit 4f0611af47e25807cf18cd2b4d4e94206c75b29e
Author: Stephen Hemminger <shemminger@vyatta.com>
Date:   Fri May 15 06:11:58 2009 +0000

    bridge: fix initial packet flood if !STP

    If bridge is configured with no STP and forwarding delay of 0 (which
    is typical for virtualization) then when link starts it will flood all
    packets for the first 20 seconds.

    This bug was introduced by a combination of earlier changes:
      * forwarding database uses hold time of zero to indicate
        user wants to always flood packets
      * optimzation of the case of forwarding delay of 0 avoids the initial
        timer tick

    The fix is to just skip all the topology change detection code if
    kernel STP is not being used.

brew:
https://brewweb.devel.redhat.com/taskinfo?taskID=3260785

Tested by customer

Signed-off-by: Jiri Pirko <jpirko@redhat.com>

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index 59dd541..184f0de 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -298,6 +298,9 @@ void br_topology_change_detection(struct net_bridge *br)
 {
 	int isroot = br_is_root_bridge(br);
 
+	if (!br->stp_enabled)
+		return;
+
 	pr_info("%s: topology change detected, %s\n", br->dev->name,
 		isroot ? "propagating" : "sending tcn bpdu");