[NETLINK]: Directly return -EINTR from netlink_dump_start()

Now that all users of netlink_dump_start() use netlink_run_queue()
to process the receive queue, it is possible to return -EINTR from
netlink_dump_start() directly, therefore simplying the callers.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 1823b7c..2cbf168 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1426,7 +1426,12 @@
 
 	netlink_dump(sk);
 	sock_put(sk);
-	return 0;
+
+	/* We successfully started a dump, by returning -EINTR we
+	 * signal the queue mangement to interrupt processing of
+	 * any netlink messages so userspace gets a chance to read
+	 * the results. */
+	return -EINTR;
 }
 
 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)