net: add netlink_ext_ack argument to rtnl_link_ops.slave_validate

Add support for extended error reporting.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/rtnetlink.h

@@ -91,7 +91,8 @@ struct rtnl_link_ops {
 	int			slave_maxtype;
 	const struct nla_policy	*slave_policy;
 	int			(*slave_validate)(struct nlattr *tb[],
-						  struct nlattr *data[]);
+						  struct nlattr *data[],
+						  struct netlink_ext_ack *extack);
 	int			(*slave_changelink)(struct net_device *dev,
 						    struct net_device *slave_dev,
 						    struct nlattr *tb[],

net/core/rtnetlink.c

@@ -2601,7 +2601,8 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 				slave_data = slave_attr;
 			}
 			if (m_ops->slave_validate) {
-				err = m_ops->slave_validate(tb, slave_data);
+				err = m_ops->slave_validate(tb, slave_data,
+							    extack);
 				if (err < 0)
 					return err;
 			}