[PATCH net-next 10/13] net: sched: red: notify drivers about RED's limit parameter

[Jakub Kicinski <jakub.kicinski@netronome.com>]

RED qdisc's limit parameter changes the behaviour of the qdisc,
for instance if it's set to 0 qdisc will drop all the packets.

When replace operation happens and parameter is set to non-0
a new fifo qdisc will be instantiated and replace the old child
qdisc which will be destroyed.

Drivers need to know the parameter, even if they don't impose
the actual limit to be able to reliably reconstruct the Qdisc
hierarchy.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
---
 include/net/pkt_cls.h | 1 +
 net/sched/sch_red.c   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 5d31820b7e80..c497ada7f591 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -850,6 +850,7 @@ struct tc_red_qopt_offload_params {
 	u32 min;
 	u32 max;
 	u32 probability;
+	u32 limit;
 	bool is_ecn;
 	bool is_harddrop;
 	struct gnet_stats_queue *qstats;
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 4b5ca172ee2d..9df9942340ea 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -166,6 +166,7 @@ static int red_offload(struct Qdisc *sch, bool enable)
 		opt.set.min = q->parms.qth_min >> q->parms.Wlog;
 		opt.set.max = q->parms.qth_max >> q->parms.Wlog;
 		opt.set.probability = q->parms.max_P;
+		opt.set.limit = q->limit;
 		opt.set.is_ecn = red_use_ecn(q);
 		opt.set.is_harddrop = red_use_harddrop(q);
 		opt.set.qstats = &sch->qstats;
-- 
2.17.1