vlan: fix bond/team enslave of vlan challenged slave/port

In vlan_uses_dev() check for number of vlan devs rather than existence
of vlan_info. The reason is that vlan id 0 is there without appropriate
vlan dev on it by default which prevented from enslaving vlan challenged
dev.

Reported-by: Jon Stanley <jstanley@rmrf.net>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 1 deletions

diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index fbbf1fa00940..65e06abe023f 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -366,6 +366,13 @@ EXPORT_SYMBOL(vlan_vids_del_by_dev);
 
 bool vlan_uses_dev(const struct net_device *dev)
 {
-        return rtnl_dereference(dev->vlan_info) ? true : false;
+        struct vlan_info *vlan_info;
+
+        ASSERT_RTNL();
+
+        vlan_info = rtnl_dereference(dev->vlan_info);
+        if (!vlan_info)
+                return false;
+        return vlan_info->grp.nr_vlan_devs ? true : false;
 }
 EXPORT_SYMBOL(vlan_uses_dev);