Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6

[pandora-kernel.git] / net / ipv4 / tcp_cong.c

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index bbf2d66..e688c68 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -174,6 +174,34 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
        return err;
 }
 
+
+/*
+ * Linear increase during slow start
+ */
+void tcp_slow_start(struct tcp_sock *tp)
+{
+       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;
+
+               /* We MAY increase by 2 if discovered delayed ack */
+               if (sysctl_tcp_abc > 1 && tp->bytes_acked > 2*tp->mss_cache) {
+                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                               tp->snd_cwnd++;
+               }
+       }
+       tp->bytes_acked = 0;
+
+       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+               tp->snd_cwnd++;
+}
+EXPORT_SYMBOL_GPL(tcp_slow_start);
+
 /*
  * TCP Reno congestion control
  * This is special case used for fallback as well.
@@ -186,24 +214,32 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 rtt, u32 in_flight,
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       if (in_flight < tp->snd_cwnd)
+       if (!tcp_is_cwnd_limited(sk, in_flight))
                return;
 
-        if (tp->snd_cwnd <= tp->snd_ssthresh) {
-                /* In "safe" area, increase. */
-               if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                       tp->snd_cwnd++;
-       } else {
-                /* In dangerous area, increase slowly.
-                * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
-                */
-               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-                               tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               } else
-                       tp->snd_cwnd_cnt++;
-       }
+       /* In "safe" area, increase. */
+        if (tp->snd_cwnd <= tp->snd_ssthresh)
+               tcp_slow_start(tp);
+
+       /* In dangerous area, increase slowly. */
+       else if (sysctl_tcp_abc) {
+               /* RFC3465: Apppriate Byte Count
+                * increase once for each full cwnd acked
+                */
+               if (tp->bytes_acked >= tp->snd_cwnd*tp->mss_cache) {
+                       tp->bytes_acked -= tp->snd_cwnd*tp->mss_cache;
+                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                               tp->snd_cwnd++;
+               }
+       } else {
+               /* In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd */
+               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+                       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                               tp->snd_cwnd++;
+                       tp->snd_cwnd_cnt = 0;
+               } else
+                       tp->snd_cwnd_cnt++;
+       }
 }
 EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);