bridge: netlink: export root path cost

Add IFLA_BR_ROOT_PATH_COST and export it via netlink.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 652db1c..cd0488b 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -857,6 +857,7 @@
 	       nla_total_size(sizeof(struct ifla_bridge_id)) +   /* IFLA_BR_ROOT_ID */
 	       nla_total_size(sizeof(struct ifla_bridge_id)) +   /* IFLA_BR_BRIDGE_ID */
 	       nla_total_size(sizeof(u16)) +    /* IFLA_BR_ROOT_PORT */
+	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_ROOT_PATH_COST */
 	       0;
 }
 
@@ -890,7 +891,8 @@
 	    nla_put_u16(skb, IFLA_BR_GROUP_FWD_MASK, group_fwd_mask) ||
 	    nla_put(skb, IFLA_BR_ROOT_ID, sizeof(root_id), &root_id) ||
 	    nla_put(skb, IFLA_BR_BRIDGE_ID, sizeof(bridge_id), &bridge_id) ||
-	    nla_put_u16(skb, IFLA_BR_ROOT_PORT, br->root_port))
+	    nla_put_u16(skb, IFLA_BR_ROOT_PORT, br->root_port) ||
+	    nla_put_u32(skb, IFLA_BR_ROOT_PATH_COST, br->root_path_cost))
 		return -EMSGSIZE;
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING