[GENETLINK] ctrl: Avoid empty CTRL_ATTR_OPS attribute when dumping

Based on Jamal's patch but compiled and even tested. :-)
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/genetlink.c

@@ -394,10 +394,7 @@ static struct genl_family genl_ctrl = {
 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 			  u32 flags, struct sk_buff *skb, u8 cmd)
 {
-	struct nlattr *nla_ops;
-	struct genl_ops *ops;
 	void *hdr;
-	int idx = 1;
 
 	hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 	if (hdr == NULL)
@@ -409,6 +406,11 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 	NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 	NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 
+	if (!list_empty(&family->ops_list)) {
+		struct nlattr *nla_ops;
+		struct genl_ops *ops;
+		int idx = 1;
+
 		nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 		if (nla_ops == NULL)
 			goto nla_put_failure;
@@ -436,6 +438,7 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 		}
 
 		nla_nest_end(skb, nla_ops);
+	}
 
 	return genlmsg_end(skb, hdr);