bridge: Check return of dev_set_promiscuity

dev_set_promiscuity/allmulti might overflow.
Commit: "netdevice: Fix promiscuity and allmulti overflow" in net-next makes
dev_set_promiscuity/allmulti return error number if overflow happened.

Here, we check the positive increment for promiscuity to get error return.
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -373,6 +373,10 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	if (IS_ERR(p))
 		return PTR_ERR(p);
 
+	err = dev_set_promiscuity(dev, 1);
+	if (err)
+		goto put_back;
+
 	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 				   SYSFS_BRIDGE_PORT_ATTR);
 	if (err)
@@ -388,7 +392,6 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 
 	rcu_assign_pointer(dev->br_port, p);
 	dev_disable_lro(dev);
-	dev_set_promiscuity(dev, 1);
 
 	list_add_rcu(&p->list, &br->port_list);
 
@@ -412,12 +415,12 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	br_fdb_delete_by_port(br, p, 1);
 err1:
 	kobject_del(&p->kobj);
-	goto put_back;
 err0:
 	kobject_put(&p->kobj);
-
+	dev_set_promiscuity(dev, -1);
 put_back:
 	dev_put(dev);
+	kfree(p);
 	return err;
 }