[TCP]: congestion control API pass RTT in microseconds
This patch changes the API for the callback that is done after an ACK is
received. It solves a couple of issues:
* Some congestion controls want higher resolution value of RTT
(controlled by TCP_CONG_RTT_SAMPLE flag). These don't really want a ktime, but
all compute a RTT in microseconds.
* Other congestion control could use RTT at jiffies resolution.
To keep API consistent the units should be the same for both cases, just the
resolution should change.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index cc5de6f..64f1cba 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -83,18 +83,16 @@
}
/* Measure RTT for each ack. */
-static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
+static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, s32 rtt)
{
struct illinois *ca = inet_csk_ca(sk);
- u32 rtt;
ca->acked = pkts_acked;
- if (ktime_equal(last, net_invalid_timestamp()))
+ /* dup ack, no rtt sample */
+ if (rtt < 0)
return;
- rtt = ktime_to_us(net_timedelta(last));
-
/* ignore bogus values, this prevents wraparound in alpha math */
if (rtt > RTT_MAX)
rtt = RTT_MAX;