From bce552fd6f6e37f9567c85c4f0d6d1987eef379f Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Tue, 14 Nov 2017 11:27:01 -0800 Subject: [PATCH] netem: use 64 bit divide by rate Since times are now expressed in nanosecond, need to now do true 64 bit divide. Old code would truncate rate at 32 bits. Rename function to better express current usage. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/sched/sch_netem.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index b686e755fda9..644323d6081c 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -339,10 +339,8 @@ static s64 tabledist(s64 mu, s64 sigma, return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; } -static u64 packet_len_2_sched_time(unsigned int len, - struct netem_sched_data *q) +static u64 packet_time_ns(u64 len, const struct netem_sched_data *q) { - u64 offset; len += q->packet_overhead; if (q->cell_size) { @@ -352,9 +350,8 @@ static u64 packet_len_2_sched_time(unsigned int len, cells++; len = cells * (q->cell_size + q->cell_overhead); } - offset = (u64)len * NSEC_PER_SEC; - do_div(offset, q->rate); - return offset; + + return div64_u64(len * NSEC_PER_SEC, q->rate); } static void tfifo_reset(struct Qdisc *sch) @@ -556,7 +553,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, now = last->time_to_send; } - delay += packet_len_2_sched_time(qdisc_pkt_len(skb), q); + delay += packet_time_ns(qdisc_pkt_len(skb), q); } cb->time_to_send = now + delay; -- 2.30.2