net_sched: restore "overhead xxx" handling

commit 56b765b79 ("htb: improved accuracy at high rates")
broke the "overhead xxx" handling, as well as the "linklayer atm"
attribute.

tc class add ... htb rate X ceil Y linklayer atm overhead 10

This patch restores the "overhead xxx" handling, for htb, tbf
and act_police

The "linklayer atm" thing needs a separate fix.

Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vimalkumar <j.vimal@gmail.com>
Cc: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index eac7e0e..2022408 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -898,14 +898,16 @@
 	WARN_ON(timer_pending(&dev->watchdog_timer));
 }
 
-void psched_ratecfg_precompute(struct psched_ratecfg *r, u32 rate)
+void psched_ratecfg_precompute(struct psched_ratecfg *r,
+			       const struct tc_ratespec *conf)
 {
 	u64 factor;
 	u64 mult;
 	int shift;
 
-	r->rate_bps = (u64)rate << 3;
-	r->shift = 0;
+	memset(r, 0, sizeof(*r));
+	r->overhead = conf->overhead;
+	r->rate_bps = (u64)conf->rate << 3;
 	r->mult = 1;
 	/*
 	 * Calibrate mult, shift so that token counting is accurate