sock: permit SO_ZEROCOPY on PF_RDS socket

allow the application to set SO_ZEROCOPY on the underlying sk
of a PF_RDS socket
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -1049,18 +1049,21 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case SO_ZEROCOPY:
-		if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
-			ret = -ENOTSUPP;
-		else if (sk->sk_protocol != IPPROTO_TCP)
+		if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6) {
+			if (sk->sk_protocol != IPPROTO_TCP)
 				ret = -ENOTSUPP;
 			else if (sk->sk_state != TCP_CLOSE)
 				ret = -EBUSY;
-		else if (val < 0 || val > 1)
+		} else if (sk->sk_family != PF_RDS) {
+			ret = -ENOTSUPP;
+		}
+		if (!ret) {
+			if (val < 0 || val > 1)
 				ret = -EINVAL;
 			else
 				sock_valbool_flag(sk, SOCK_ZEROCOPY, valbool);
 			break;
-
+		}
 	default:
 		ret = -ENOPROTOOPT;
 		break;