[NET]: Convert xtime.tv_sec to get_seconds()

[linux-2.6-omap-h63xx.git] / net / ipv4 / tcp_cong.c

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 5ca7723d07987a604bb6382f0fdefc3f1850b2cb..ccd88407e0cdf56e4154c858b120605756f05c14 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -12,6 +12,8 @@
 #include <linux/list.h>
 #include <net/tcp.h>
 
+int sysctl_tcp_max_ssthresh = 0;
+
 static DEFINE_SPINLOCK(tcp_cong_list_lock);
 static LIST_HEAD(tcp_cong_list);
 
@@ -29,7 +31,7 @@ static struct tcp_congestion_ops *tcp_ca_find(const char *name)
 }
 
 /*
- * Attach new congestion control algorthim to the list
+ * Attach new congestion control algorithm to the list
  * of available options.
  */
 int tcp_register_congestion_control(struct tcp_congestion_ops *ca)
@@ -77,18 +79,19 @@ void tcp_init_congestion_control(struct sock *sk)
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_congestion_ops *ca;
 
-       if (icsk->icsk_ca_ops != &tcp_init_congestion_ops)
-               return;
+       /* if no choice made yet assign the current value set as default */
+       if (icsk->icsk_ca_ops == &tcp_init_congestion_ops) {
+               rcu_read_lock();
+               list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
+                       if (try_module_get(ca->owner)) {
+                               icsk->icsk_ca_ops = ca;
+                               break;
+                       }
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
-               if (try_module_get(ca->owner)) {
-                       icsk->icsk_ca_ops = ca;
-                       break;
+                       /* fallback to next available */
                }
-
+               rcu_read_unlock();
        }
-       rcu_read_unlock();
 
        if (icsk->icsk_ca_ops->init)
                icsk->icsk_ca_ops->init(sk);
@@ -236,6 +239,7 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
 
        rcu_read_lock();
        ca = tcp_ca_find(name);
+
        /* no change asking for existing value */
        if (ca == icsk->icsk_ca_ops)
                goto out;
@@ -261,7 +265,8 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
        else {
                tcp_cleanup_congestion_control(sk);
                icsk->icsk_ca_ops = ca;
-               if (icsk->icsk_ca_ops->init)
+
+               if (sk->sk_state != TCP_CLOSE && icsk->icsk_ca_ops->init)
                        icsk->icsk_ca_ops->init(sk);
        }
  out:
@@ -271,10 +276,13 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
 
 
 /*
- * Linear increase during slow start
+ * Slow start (exponential increase) with
+ * RFC3742 Limited Slow Start (fast linear increase) support.
  */
 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
@@ -283,17 +291,25 @@ void tcp_slow_start(struct tcp_sock *tp)
                 */
                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++;
-               }
        }
+
+       if (sysctl_tcp_max_ssthresh > 0 &&
+           tp->snd_cwnd > sysctl_tcp_max_ssthresh)
+               cnt += sysctl_tcp_max_ssthresh>>1;
+       else
+               cnt += tp->snd_cwnd;
+
+       /* RFC3465: 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;
 
-       if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-               tp->snd_cwnd++;
+       tp->snd_cwnd_cnt += cnt;
+       while (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+               tp->snd_cwnd_cnt -= tp->snd_cwnd;
+               if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                       tp->snd_cwnd++;
+       }
 }
 EXPORT_SYMBOL_GPL(tcp_slow_start);
 
@@ -313,28 +329,28 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 rtt, u32 in_flight,
                return;
 
        /* In "safe" area, increase. */
-        if (tp->snd_cwnd <= tp->snd_ssthresh)
+       if (tp->snd_cwnd <= tp->snd_ssthresh)
                tcp_slow_start(tp);
 
-       /* In dangerous area, increase slowly. */
+       /* In dangerous area, increase slowly. */
        else if (sysctl_tcp_abc) {
-               /* RFC3465: Appropriate 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++;
-       }
+               /* RFC3465: Appropriate 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);