From 776e53a8d90699f74f969dc51dfbff988728940b Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Sat, 14 Mar 2009 18:01:41 -0700
Subject: [PATCH] brcompat: When adding or removing datapath ports, wait for
 them to appear/disappear.

---
 datapath/brcompat.c                      | 34 ++++++++++++++++++++----
 datapath/linux-2.6/compat-2.6/compat26.h |  6 +++++
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/datapath/brcompat.c b/datapath/brcompat.c
index 02a15b82..10d8c8ce 100644
--- a/datapath/brcompat.c
+++ b/datapath/brcompat.c
@@ -1,10 +1,12 @@
 #include <linux/kernel.h>
 #include <asm/uaccess.h>
 #include <linux/completion.h>
+#include <linux/delay.h>
 #include <linux/etherdevice.h>
 #include <linux/if_bridge.h>
 #include <linux/rculist.h>
 #include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
 #include <net/genetlink.h>
 
 #include "compat.h"
@@ -157,12 +159,11 @@ old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 		struct net_device *port;
 		int err;
 
-		port = dev_get_by_index(&init_net, args[1]);
+		port = __dev_get_by_index(&init_net, args[1]);
 		if (!port) 
 			return -EINVAL;
 
 		err = brc_send_port_add_del(dev, port, args[0] == BRCTL_ADD_IF);
-		dev_put(port);
 		return err;
 	}
 
@@ -225,12 +226,11 @@ brc_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 		case SIOCBRDELIF: {
 			struct net_device *port;
 
-			port = dev_get_by_index(&init_net, rq->ifr_ifindex);
+			port = __dev_get_by_index(&init_net, rq->ifr_ifindex);
 			if (!port) 
 				return -EINVAL;
 
 			err = brc_send_port_add_del(dev, port, cmd == SIOCBRADDIF);
-			dev_put(port);
 			break;
 		}
 
@@ -358,7 +358,9 @@ int brc_send_port_add_del(struct net_device *dev, struct net_device *port,
 	struct dp_dev *dp_dev = netdev_priv(dev);
 	struct datapath *dp = dp_dev->dp;
 	struct sk_buff *skb;
+	int error;
 	void *data;
+	int i;
 
 	skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb == NULL)
@@ -388,7 +390,29 @@ int brc_send_port_add_del(struct net_device *dev, struct net_device *port,
 	NLA_PUT_STRING(skb, BRC_GENL_A_PORT_NAME, port->name);
 
 	genlmsg_end(skb, data);
-	return genlmsg_multicast(skb, 0, brc_mc_group.id, GFP_KERNEL);
+	error = genlmsg_multicast(skb, 0, brc_mc_group.id, GFP_KERNEL);
+	if (error)
+		return error;
+
+	for (i = 0; i < 100; i++) {
+		int dev_ifindex = dev->ifindex;
+		int port_ifindex = port->ifindex;
+
+		rtnl_unlock();
+		msleep(10);
+		rtnl_lock();
+
+		dev = __dev_get_by_index(&init_net, dev_ifindex);
+		port = __dev_get_by_index(&init_net, port_ifindex);
+		if (!dev || !port)
+			return ENODEV;
+
+		if (add && port->br_port)
+			return port->br_port->dev ? 0 : -EBUSY;
+		else if (!add && !port->br_port)
+			return 0;
+	}
+	return -ETIMEDOUT;
 
 nla_put_failure:
 err:
diff --git a/datapath/linux-2.6/compat-2.6/compat26.h b/datapath/linux-2.6/compat-2.6/compat26.h
index 37f6a4f8..61448d63 100644
--- a/datapath/linux-2.6/compat-2.6/compat26.h
+++ b/datapath/linux-2.6/compat-2.6/compat26.h
@@ -17,6 +17,12 @@
 #define dev_get_by_index(net, ifindex) \
 		dev_get_by_index((ifindex))
 
+#define __dev_get_by_name(net, name) \
+		__dev_get_by_name((name))
+
+#define __dev_get_by_index(net, ifindex) \
+		__dev_get_by_index((ifindex))
+
 #endif /* linux kernel <= 2.6.23 */
 
 
-- 
2.30.2