[TCP]: No need to re-count fackets_out/sacked_out at RTO

Both sacked_out and fackets_out are directly known from how
parameter. Since fackets_out is accurate, there's no need for
recounting (sacked_out was previously unnecessarily counted
in the loop anyway).

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

1 files changed, 16 insertions, 10 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bd18c252dee4..a06603912137 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1711,18 +1711,23 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
         tcp_clear_retrans_hints_partial(tp);
 }
 
-void tcp_clear_retrans(struct tcp_sock *tp)
+static void tcp_clear_retrans_partial(struct tcp_sock *tp)
 {
         tp->retrans_out = 0;
-
-        tp->fackets_out = 0;
-        tp->sacked_out = 0;
         tp->lost_out = 0;
 
         tp->undo_marker = 0;
         tp->undo_retrans = 0;
 }
 
+void tcp_clear_retrans(struct tcp_sock *tp)
+{
+        tcp_clear_retrans_partial(tp);
+
+        tp->fackets_out = 0;
+        tp->sacked_out = 0;
+}
+
 /* Enter Loss state. If "how" is not zero, forget all SACK information
  * and reset tags completely, otherwise preserve SACKs. If receiver
  * dropped its ofo queue, we will know this due to reneging detection.
@@ -1732,7 +1737,6 @@ void tcp_enter_loss(struct sock *sk, int how)
         const struct inet_connection_sock *icsk = inet_csk(sk);
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
-        int cnt = 0;
 
         /* Reduce ssthresh if it has not yet been made inside this window. */
         if (icsk->icsk_ca_state <= TCP_CA_Disorder || tp->snd_una == tp->high_seq ||
@@ -1746,7 +1750,10 @@ void tcp_enter_loss(struct sock *sk, int how)
         tp->snd_cwnd_stamp = tcp_time_stamp;
 
         tp->bytes_acked = 0;
-        tcp_clear_retrans(tp);
+        tcp_clear_retrans_partial(tp);
+
+        if (tcp_is_reno(tp))
+                tcp_reset_reno_sack(tp);
 
         if (!how) {
                 /* Push undo marker, if it was plain RTO and nothing
@@ -1754,13 +1761,15 @@ void tcp_enter_loss(struct sock *sk, int how)
                 tp->undo_marker = tp->snd_una;
                 tcp_clear_retrans_hints_partial(tp);
         } else {
+                tp->sacked_out = 0;
+                tp->fackets_out = 0;
                 tcp_clear_all_retrans_hints(tp);
         }
 
         tcp_for_write_queue(skb, sk) {
                 if (skb == tcp_send_head(sk))
                         break;
-                cnt += tcp_skb_pcount(skb);
+
                 if (TCP_SKB_CB(skb)->sacked&TCPCB_RETRANS)
                         tp->undo_marker = 0;
                 TCP_SKB_CB(skb)->sacked &= (~TCPCB_TAGBITS)|TCPCB_SACKED_ACKED;
@@ -1768,9 +1777,6 @@ void tcp_enter_loss(struct sock *sk, int how)
                         TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED;
                         TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                         tp->lost_out += tcp_skb_pcount(skb);
-                } else {
-                        tp->sacked_out += tcp_skb_pcount(skb);
-                        tp->fackets_out = cnt;
                 }
         }
         tcp_verify_left_out(tp);