--- linux-2.6.15.4-orig/include/linux/pkt_sched.h	2006-02-10 08:22:48.000000000 +0100
+++ linux-2.6.15.4/include/linux/pkt_sched.h	2006-03-01 20:12:01.000000000 +0100
@@ -78,7 +78,7 @@ struct tc_ratespec
 	unsigned char	cell_log;
 	unsigned char	__reserved;
 	unsigned short	feature;
-	short		addend;
+	unsigned short	overhead;
 	unsigned short	mpu;
 	__u32		rate;
 };
--- linux-2.6.15.4-orig/net/sched/sch_htb.c	2006-02-10 08:22:48.000000000 +0100
+++ linux-2.6.15.4/net/sched/sch_htb.c	2006-03-01 20:12:01.000000000 +0100
@@ -206,7 +206,8 @@ struct htb_class
 static __inline__ long L2T(struct htb_class *cl,struct qdisc_rate_table *rate,
 	int size)
 { 
-    int slot = size >> rate->rate.cell_log;
+    int overhead = rate->rate.overhead;
+    int slot = (size-1+overhead) >> rate->rate.cell_log;
     if (slot > 255) {
 	cl->xstats.giants++;
 	slot = 255;