new helper: memcpy_to_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c239f47..435443b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1349,7 +1349,7 @@
 
 		if (len > 0) {
 			if (!(flags & MSG_TRUNC))
-				err = memcpy_toiovec(msg->msg_iov, &c, 1);
+				err = memcpy_to_msg(msg, &c, 1);
 			len = 1;
 		} else
 			msg->msg_flags |= MSG_TRUNC;