From: Eric Dumazet <edumazet@google.com>
Date: Mon, 23 Dec 2019 20:27:51 +0000 (-0800)
Subject: tcp_cubic: remove one conditional from hystart_update()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=35821fc2b41c51161e503bade3630603668dd3af;p=linux.git

tcp_cubic: remove one conditional from hystart_update()

If we initialize ca->curr_rtt to ~0U, we do not need to test
for zero value in hystart_update()

We only read ca->curr_rtt if at least HYSTART_MIN_SAMPLES have
been processed, and thus ca->curr_rtt will have a sane value.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 297936033c335..5eff762acd7fe 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -133,7 +133,7 @@ static inline void bictcp_hystart_reset(struct sock *sk)
 
 	ca->round_start = ca->last_ack = bictcp_clock();
 	ca->end_seq = tp->snd_nxt;
-	ca->curr_rtt = 0;
+	ca->curr_rtt = ~0U;
 	ca->sample_cnt = 0;
 }
 
@@ -402,7 +402,7 @@ static void hystart_update(struct sock *sk, u32 delay)
 	if (hystart_detect & HYSTART_DELAY) {
 		/* obtain the minimum delay of more than sampling packets */
 		if (ca->sample_cnt < HYSTART_MIN_SAMPLES) {
-			if (ca->curr_rtt == 0 || ca->curr_rtt > delay)
+			if (ca->curr_rtt > delay)
 				ca->curr_rtt = delay;
 
 			ca->sample_cnt++;