SUNRPC: Clean up xs_udp_data_receive()

	struct sock *sk;

	int err;

restart:

	mutex_lock(&transport->recv_mutex);

	sk = transport->inet;

	if (sk == NULL)

		goto out;

	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);

	for (;;) {

		skb = skb_recv_udp(sk, 0, 1, &err);

		if (skb != NULL) {

		if (skb == NULL)

			break;

		xs_udp_data_read_skb(&transport->xprt, sk, skb);

		consume_skb(skb);

			continue;

		}

		if (!test_and_clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))

			break;

		if (need_resched()) {

			mutex_unlock(&transport->recv_mutex);

		cond_resched();

			goto restart;

		}

	}

out:

	mutex_unlock(&transport->recv_mutex);