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tcp_cubic: fix comparison of jiffies

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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 <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2011-03-14 07:52:13 +00:00 committed by David S. Miller
parent febf081987
commit c54b4b7655
1 changed files with 4 additions and 2 deletions
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6
net/ipv4/tcp_cubic.c
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@ -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;
}