new helper: skb_copy_and_csum_datagram_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 78c299f..cbe4b20 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2651,6 +2651,11 @@
 }
 int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen,
 				     struct iovec *iov);
+static inline int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
+			    struct msghdr *msg)
+{
+	return skb_copy_and_csum_datagram_iovec(skb, hlen, msg->msg_iov);
+}
 int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
 				 const struct iovec *from, int from_offset,
 				 int len);