[PATCH] netem: fix 64 bit divide

[Stephen Hemminger <stephen@networkplumber.org>]

Since times are now expressed in 64 bit nanosecond, need to now do
true 64 bit divide. Change the name of the function to bette express
the new units.

Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in nanoseconds")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 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;
-- 
2.11.0