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Diffstat (limited to 'net/ipv4/tcp_cong.c')
-rw-r--r--net/ipv4/tcp_cong.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 4451750b478c..3a6be23d222f 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -274,6 +274,27 @@ 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;
+
+ if (!sk_can_gso(sk))
+ return 0;
+
+ left = tp->snd_cwnd - in_flight;
+ if (sysctl_tcp_tso_win_divisor)
+ return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
+ else
+ return left <= tcp_max_burst(tp);
+}
+EXPORT_SYMBOL_GPL(tcp_is_cwnd_limited);
/*
* Slow start is used when congestion window is less than slow start