net/switchdev: Export the same parent ID service function

This helper serves to know if two switchdev port netdevices belong to the
same HW ASIC, e.g to figure out if forwarding offload is possible between them.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/switchdev.h

@@ -227,6 +227,8 @@ void switchdev_port_fwd_mark_set(struct net_device *dev,
 				 struct net_device *group_dev,
 				 bool joining);
 
+bool switchdev_port_same_parent_id(struct net_device *a,
+				   struct net_device *b);
 #else
 
 static inline void switchdev_deferred_process(void)
@@ -351,6 +353,12 @@ static inline void switchdev_port_fwd_mark_set(struct net_device *dev,
 {
 }
 
+static inline bool switchdev_port_same_parent_id(struct net_device *a,
+						 struct net_device *b)
+{
+	return false;
+}
+
 #endif
 
 #endif /* _LINUX_SWITCHDEV_H_ */

net/switchdev/switchdev.c

@@ -1286,7 +1286,7 @@ void switchdev_fib_ipv4_abort(struct fib_info *fi)
 }
 EXPORT_SYMBOL_GPL(switchdev_fib_ipv4_abort);
 
-static bool switchdev_port_same_parent_id(struct net_device *a,
+bool switchdev_port_same_parent_id(struct net_device *a,
 				   struct net_device *b)
 {
 	struct switchdev_attr a_attr = {
@@ -1323,6 +1323,7 @@ static u32 switchdev_port_fwd_mark_get(struct net_device *dev,
 
 	return dev->ifindex;
 }
+EXPORT_SYMBOL_GPL(switchdev_port_same_parent_id);
 
 static void switchdev_port_fwd_mark_reset(struct net_device *group_dev,
 					  u32 old_mark, u32 *reset_mark)