tcp: convert retransmit_cnt_hint to seqno

Main benefit in this is that we can then freely point
the retransmit_skb_hint to anywhere we want to because
there's no longer need to know what would be the count
changes involve, and since this is really used only as a
terminator, unnecessary work is one time walk at most,
and if some retransmissions are necessary after that
point later on, the walk is not full waste of time
anyway.

Since retransmit_high must be kept valid, all lost
markers must ensure that.

Now I also have learned how those "holes" in the
rexmittable skbs can appear, mtu probe does them. So
I removed the misleading comment as well.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 2e2557388e36..d7637c4b2840 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -358,7 +358,7 @@ struct tcp_sock {
                                          */
 
         int     lost_cnt_hint;
-        int     retransmit_cnt_hint;
+        u32     retransmit_high;        /* L-bits may be on up to this seqno */
 
         u32     lost_retrans_low;       /* Sent seq after any rxmit (lowest) */
 
diff --git a/include/net/tcp.h b/include/net/tcp.h
index b71676326950..d0e90c50722b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -472,6 +472,8 @@ extern void tcp_send_delayed_ack(struct sock *sk);
 
 /* tcp_input.c */
 extern void tcp_cwnd_application_limited(struct sock *sk);
+extern void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp,
+                                            struct sk_buff *skb);
 
 /* tcp_timer.c */
 extern void tcp_init_xmit_timers(struct sock *);