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>
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 71d5f2f..43bb34c 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -342,9 +342,11 @@
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;
}