tcp: update reordering first before detecting loss

tcp_mark_lost_retrans is not used when FACK is disabled. Since
tcp_update_reordering may disable FACK, it should be called first
before tcp_mark_lost_retrans.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_input.c

@@ -1820,14 +1820,12 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
 	for (j = 0; j < used_sacks; j++)
 		tp->recv_sack_cache[i++] = sp[j];
 
-	tcp_mark_lost_retrans(sk);
-
-	tcp_verify_left_out(tp);
-
 	if ((state.reord < tp->fackets_out) &&
 	    ((inet_csk(sk)->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker))
 		tcp_update_reordering(sk, tp->fackets_out - state.reord, 0);
 
+	tcp_mark_lost_retrans(sk);
+	tcp_verify_left_out(tp);
 out:
 
 #if FASTRETRANS_DEBUG > 0