tcp: fix false undo corner cases

[android-x86/kernel.git] / net / ipv4 / tcp_output.c

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index d92bce0..179b51e 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2525,8 +2525,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
                if (!tp->retrans_stamp)
                        tp->retrans_stamp = TCP_SKB_CB(skb)->when;
 
-               tp->undo_retrans += tcp_skb_pcount(skb);
-
                /* snd_nxt is stored to detect loss of retransmitted segment,
                 * see tcp_input.c tcp_sacktag_write_queue().
                 */
@@ -2534,6 +2532,10 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
        } else if (err != -EBUSY) {
                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL);
        }
+
+       if (tp->undo_retrans < 0)
+               tp->undo_retrans = 0;
+       tp->undo_retrans += tcp_skb_pcount(skb);
        return err;
 }