X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=net%2Fipv4%2Ftcp_cong.c;h=6a250828b767aef7f037a3cf10d10b1dd74625cb;hb=76d39d0a1947fee4c29976e507fb93188eaa2b38;hp=86b26539e54b8a8572919acd9c3880fe232ec89a;hpb=805f53f085346b6765eda02820721a14ce0d644f;p=linux-2.6-omap-h63xx.git

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 86b26539e54..6a250828b76 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -274,32 +274,55 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
 	return err;
 }
 
+/* RFC2861 Check whether we are limited by application or congestion window
+ * This is the inverse of cwnd check in tcp_tso_should_defer
+ */
+int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
+{
+	const struct tcp_sock *tp = tcp_sk(sk);
+	u32 left;
+
+	if (in_flight >= tp->snd_cwnd)
+		return 1;
+
+	left = tp->snd_cwnd - in_flight;
+	if (sk_can_gso(sk) &&
+	    left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd &&
+	    left * tp->mss_cache < sk->sk_gso_max_size)
+		return 1;
+	return left <= tcp_max_burst(tp);
+}
+EXPORT_SYMBOL_GPL(tcp_is_cwnd_limited);
 
 /*
- * Slow start (exponential increase) with
- * RFC3742 Limited Slow Start (fast linear increase) support.
+ * Slow start is used when congestion window is less than slow start
+ * threshold. This version implements the basic RFC2581 version
+ * and optionally supports:
+ * 	RFC3742 Limited Slow Start  	  - growth limited to max_ssthresh
+ *	RFC3465 Appropriate Byte Counting - growth limited by bytes acknowledged
  */
 void tcp_slow_start(struct tcp_sock *tp)
 {
-	int cnt = 0;
-
-	if (sysctl_tcp_abc) {
-		/* RFC3465: Slow Start
-		 * TCP sender SHOULD increase cwnd by the number of
-		 * previously unacknowledged bytes ACKed by each incoming
-		 * acknowledgment, provided the increase is not more than L
-		 */
-		if (tp->bytes_acked < tp->mss_cache)
-			return;
-	}
+	int cnt; /* increase in packets */
+
+	/* RFC3465: ABC Slow start
+	 * Increase only after a full MSS of bytes is acked
+	 *
+	 * TCP sender SHOULD increase cwnd by the number of
+	 * previously unacknowledged bytes ACKed by each incoming
+	 * acknowledgment, provided the increase is not more than L
+	 */
+	if (sysctl_tcp_abc && tp->bytes_acked < tp->mss_cache)
+		return;
 
-	if (sysctl_tcp_max_ssthresh > 0 &&
-	    tp->snd_cwnd > sysctl_tcp_max_ssthresh)
-		cnt += sysctl_tcp_max_ssthresh>>1;
+	if (sysctl_tcp_max_ssthresh > 0 && tp->snd_cwnd > sysctl_tcp_max_ssthresh)
+		cnt = sysctl_tcp_max_ssthresh >> 1;	/* limited slow start */
 	else
-		cnt += tp->snd_cwnd;
+		cnt = tp->snd_cwnd;			/* exponential increase */
 
-	/* RFC3465: We MAY increase by 2 if discovered delayed ack */
+	/* RFC3465: ABC
+	 * We MAY increase by 2 if discovered delayed ack
+	 */
 	if (sysctl_tcp_abc > 1 && tp->bytes_acked >= 2*tp->mss_cache)
 		cnt <<= 1;
 	tp->bytes_acked = 0;
@@ -320,8 +343,7 @@ EXPORT_SYMBOL_GPL(tcp_slow_start);
 /* This is Jacobson's slow start and congestion avoidance.
  * SIGCOMM '88, p. 328.
  */
-void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 rtt, u32 in_flight,
-			 int flag)
+void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
 {
 	struct tcp_sock *tp = tcp_sk(sk);