Commit c54b4b76 authored Mar 14, 2011 by stephen hemminger Committed by David S. Miller Mar 14, 2011

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 <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent febf0819

net/ipv4/tcp_cubic.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}