Credits goes to Al Viro for solution.
replace
return skb_copy_datagram_iovec(skb, 0, &iov, len);
with
struct iov_iter to;
iov_iter_init(&to, READ, &iov, 1, len);
return skb_copy_datagram_iter(skb, 0, &to, len);
and everything compiled and working now 