new helper: memcpy_from_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index c559bcd..cc7a828 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -346,8 +346,7 @@
 	skb_put(skb, 2);
 
 	/* Copy user data into skb */
-	error = memcpy_fromiovec(skb_put(skb, total_len), m->msg_iov,
-				 total_len);
+	error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
 	if (error < 0) {
 		kfree_skb(skb);
 		goto error_put_sess_tun;