From c54b4b7655447c1f24f6d50779c22eba9ee0fd24 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 14 Mar 2011 07:52:13 +0000 Subject: [PATCH] tcp_cubic: fix comparison of jiffies Jiffies wraps around therefore the correct way to compare is to use cast to signed value. Note: cubic is not using full jiffies value on 64 bit arch because using full unsigned long makes struct bictcp grow too large for the available ca_priv area. Includes correction from Sangtae Ha to improve ack train detection. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/tcp_cubic.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 71d5f2f29fa..43bb34c9b8b 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -342,9 +342,11 @@ static void hystart_update(struct sock *sk, u32 delay) u32 curr_jiffies = jiffies; /* first detection parameter - ack-train detection */ - if (curr_jiffies - ca->last_jiffies <= msecs_to_jiffies(2)) { + if ((s32)(curr_jiffies - ca->last_jiffies) <= + msecs_to_jiffies(2)) { ca->last_jiffies = curr_jiffies; - if (curr_jiffies - ca->round_start >= ca->delay_min>>4) + if ((s32) (curr_jiffies - ca->round_start) > + ca->delay_min >> 4) ca->found |= HYSTART_ACK_TRAIN; } -- 2.20.1