fq_codel: should use qdisc backlog as threshold

codel_should_drop() logic allows a packet being not dropped if queue
size is under max packet size.

In fq_codel, we have two possible backlogs : The qdisc global one, and
the flow local one.

The meaningful one for codel_should_drop() should be the global backlog,
not the per flow one, so that thin flows can have a non zero drop/mark
probability.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dave Taht <dave.taht@bufferbloat.net>
Cc: Kathleen Nichols <nichols@pollere.com>
Cc: Van Jacobson <van@pollere.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index 213ef60..2f9ab17 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -77,8 +77,8 @@
 	struct codel_sched_data *q = qdisc_priv(sch);
 	struct sk_buff *skb;
 
-	skb = codel_dequeue(sch, &q->params, &q->vars, &q->stats,
-			    dequeue, &sch->qstats.backlog);
+	skb = codel_dequeue(sch, &q->params, &q->vars, &q->stats, dequeue);
+
 	/* We cant call qdisc_tree_decrease_qlen() if our qlen is 0,
 	 * or HTB crashes. Defer it for next round.
 	 */