net: sched: implement qstat helper routines

This adds helpers to manipulate qstats logic and replaces locations
that touch the counters directly. This simplifies future patches
to push qstats onto per cpu counters.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 633e32d..6c0534c 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -74,7 +74,7 @@
 		break;
 
 	case RED_PROB_MARK:
-		sch->qstats.overlimits++;
+		qdisc_qstats_overlimit(sch);
 		if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
 			q->stats.prob_drop++;
 			goto congestion_drop;
@@ -84,7 +84,7 @@
 		break;
 
 	case RED_HARD_MARK:
-		sch->qstats.overlimits++;
+		qdisc_qstats_overlimit(sch);
 		if (red_use_harddrop(q) || !red_use_ecn(q) ||
 		    !INET_ECN_set_ce(skb)) {
 			q->stats.forced_drop++;
@@ -100,7 +100,7 @@
 		sch->q.qlen++;
 	} else if (net_xmit_drop_count(ret)) {
 		q->stats.pdrop++;
-		sch->qstats.drops++;
+		qdisc_qstats_drop(sch);
 	}
 	return ret;
 
@@ -142,7 +142,7 @@
 
 	if (child->ops->drop && (len = child->ops->drop(child)) > 0) {
 		q->stats.other++;
-		sch->qstats.drops++;
+		qdisc_qstats_drop(sch);
 		sch->q.qlen--;
 		return len;
 	}