bridge: add support for user mode STP

This patchset based on work by Aji_Srinivas@emc.com provides allows
spanning tree to be controled from userspace.  Like hotplug, it
uses call_usermodehelper when spanning tree is enabled so there
is no visible API change. If call to start usermode STP fails
it falls back to existing kernel STP.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index f9ff4d57b0d7..ebb0861e9bd5 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -370,11 +370,11 @@ static void br_make_blocking(struct net_bridge_port *p)
 static void br_make_forwarding(struct net_bridge_port *p)
 {
         if (p->state == BR_STATE_BLOCKING) {
-                if (p->br->stp_enabled) {
+                if (p->br->stp_enabled == BR_KERNEL_STP)
                         p->state = BR_STATE_LISTENING;
-                } else {
+                else
                         p->state = BR_STATE_LEARNING;
-                }
+
                 br_log_state(p);
                 mod_timer(&p->forward_delay_timer, jiffies + p->br->forward_delay);     }
 }
@@ -384,6 +384,10 @@ void br_port_state_selection(struct net_bridge *br)
 {
         struct net_bridge_port *p;
 
+        /* Don't change port states if userspace is handling STP */
+        if (br->stp_enabled == BR_USER_STP)
+                return;
+
         list_for_each_entry(p, &br->port_list, list) {
                 if (p->state != BR_STATE_DISABLED) {
                         if (p->port_no == br->root_port) {