From 12de798c3944928ed8dae9e5dba774deb3305583 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@helsinki.fi>
Date: Mon, 7 Apr 2008 22:33:07 -0700
Subject: [PATCH] --- yaml --- r: 88255 b: refs/heads/master c:
 882bebaaca4bb1484078d44ef011f918c0e1e14e h: refs/heads/master i:   88253:
 72acfa36e9c4ac01dea9a9f430a09869a1d236df   88251:
 a11c6c68a8f53b4e2d5cfcbc303bab7b19e0af2b   88247:
 208c7a52d8a1f4b43bd7c5be2a8cd6e633a64040   88239:
 74ee94e2e5bd90fa90a45baf2e1e5393add90f64   88223:
 4e3fc94c0fbcde0d319e21dbbc3f0f1a72ca7671   88191:
 4dc3125d74f3dfb5af7f365fbcb4cc5d50148ed7 v: v3

---
 [refs]                      |  2 +-
 trunk/include/net/tcp.h     |  2 ++
 trunk/net/ipv4/tcp_input.c  | 24 ++++++++++++++++++------
 trunk/net/ipv4/tcp_output.c |  3 +++
 4 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/[refs] b/[refs]
index 5f9f9536f332..1d5ea682ac12 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c137f3dda04b0aee1bc6889cdc69185f53df8a82
+refs/heads/master: 882bebaaca4bb1484078d44ef011f918c0e1e14e
diff --git a/trunk/include/net/tcp.h b/trunk/include/net/tcp.h
index 7de4ea3a04d9..4fd3eb2f8ec2 100644
--- a/trunk/include/net/tcp.h
+++ b/trunk/include/net/tcp.h
@@ -752,6 +752,8 @@ static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
 	return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
 }
 
+extern int tcp_limit_reno_sacked(struct tcp_sock *tp);
+
 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
  * The exception is rate halving phase, when cwnd is decreasing towards
  * ssthresh.
diff --git a/trunk/net/ipv4/tcp_input.c b/trunk/net/ipv4/tcp_input.c
index 7d0958785bfb..b4812c3cbbcf 100644
--- a/trunk/net/ipv4/tcp_input.c
+++ b/trunk/net/ipv4/tcp_input.c
@@ -1625,13 +1625,11 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb,
 	return flag;
 }
 
-/* If we receive more dupacks than we expected counting segments
- * in assumption of absent reordering, interpret this as reordering.
- * The only another reason could be bug in receiver TCP.
+/* Limits sacked_out so that sum with lost_out isn't ever larger than
+ * packets_out. Returns zero if sacked_out adjustement wasn't necessary.
  */
-static void tcp_check_reno_reordering(struct sock *sk, const int addend)
+int tcp_limit_reno_sacked(struct tcp_sock *tp)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
 	u32 holes;
 
 	holes = max(tp->lost_out, 1U);
@@ -1639,8 +1637,20 @@ static void tcp_check_reno_reordering(struct sock *sk, const int addend)
 
 	if ((tp->sacked_out + holes) > tp->packets_out) {
 		tp->sacked_out = tp->packets_out - holes;
-		tcp_update_reordering(sk, tp->packets_out + addend, 0);
+		return 1;
 	}
+	return 0;
+}
+
+/* If we receive more dupacks than we expected counting segments
+ * in assumption of absent reordering, interpret this as reordering.
+ * The only another reason could be bug in receiver TCP.
+ */
+static void tcp_check_reno_reordering(struct sock *sk, const int addend)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	if (tcp_limit_reno_sacked(tp))
+		tcp_update_reordering(sk, tp->packets_out + addend, 0);
 }
 
 /* Emulate SACKs for SACKless connection: account for a new dupack. */
@@ -2600,6 +2610,8 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
 	case TCP_CA_Loss:
 		if (flag & FLAG_DATA_ACKED)
 			icsk->icsk_retransmits = 0;
+		if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)
+			tcp_reset_reno_sack(tp);
 		if (!tcp_try_undo_loss(sk)) {
 			tcp_moderate_cwnd(tp);
 			tcp_xmit_retransmit_queue(sk);
diff --git a/trunk/net/ipv4/tcp_output.c b/trunk/net/ipv4/tcp_output.c
index 72b9350006fe..d29ef79c00ca 100644
--- a/trunk/net/ipv4/tcp_output.c
+++ b/trunk/net/ipv4/tcp_output.c
@@ -1808,6 +1808,9 @@ void tcp_simple_retransmit(struct sock *sk)
 	if (!lost)
 		return;
 
+	if (tcp_is_reno(tp))
+		tcp_limit_reno_sacked(tp);
+
 	tcp_verify_left_out(tp);
 
 	/* Don't muck with the congestion window here.