switchdev: add new switchdev_port_bridge_getlink

Like bridge_setlink, add switchdev wrapper to handle bridge_getlink and
call into port driver to get port attrs.  For now, only BR_LEARNING and
BR_LEARNING_SYNC are returned.  To add more, we'll probably want to break
away from ndo_dflt_bridge_getlink() and build the netlink skb directly in
the switchdev code.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 397b1e6..e081d67 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -126,6 +126,9 @@
 int unregister_switchdev_notifier(struct notifier_block *nb);
 int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
 			     struct switchdev_notifier_info *info);
+int switchdev_port_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
+				  struct net_device *dev, u32 filter_mask,
+				  int nlflags);
 int switchdev_port_bridge_setlink(struct net_device *dev,
 				  struct nlmsghdr *nlh, u16 flags);
 int switchdev_port_bridge_dellink(struct net_device *dev,
@@ -179,6 +182,13 @@
 	return NOTIFY_DONE;
 }
 
+static inline int switchdev_port_bridge_getlink(struct sk_buff *skb, u32 pid,
+					    u32 seq, struct net_device *dev,
+					    u32 filter_mask, int nlflags)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int switchdev_port_bridge_setlink(struct net_device *dev,
 						struct nlmsghdr *nlh,
 						u16 flags)