From: Nogah Frankel <nogahf@mellanox.com>
Date: Wed, 10 Jan 2018 14:59:59 +0100
Subject: net: sch: red: Change offloaded xstats to be incremental
Patch-mainline: v4.16-rc1
Git-commit: f8253df553537518e9f87fa2eb599d68a2df092b
References: bsc#1109837

Change the value of the xstats requested from the driver for offloaded RED
to be incremental, like the normal stats.
It increases consistency - if a qdisc stops being offloaded its xstats
don't change.

Signed-off-by: Nogah Frankel <nogahf@mellanox.com>
Reviewed-by: Yuval Mintz <yuvalm@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c |   15 +++++++++--
 net/sched/sch_red.c                                  |   24 ++++++-------------
 2 files changed, 20 insertions(+), 19 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
@@ -213,6 +213,7 @@ mlxsw_sp_qdisc_get_red_xstats(struct mlx
 {
 	struct red_stats *xstats_base = &mlxsw_sp_qdisc->xstats_base;
 	struct mlxsw_sp_port_xstats *xstats;
+	int early_drops, marks, pdrops;
 
 	if (mlxsw_sp_qdisc->handle != handle ||
 	    mlxsw_sp_qdisc->type != MLXSW_SP_QDISC_RED)
@@ -220,9 +221,17 @@ mlxsw_sp_qdisc_get_red_xstats(struct mlx
 
 	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
 
-	res->prob_drop = xstats->wred_drop[tclass_num] - xstats_base->prob_drop;
-	res->prob_mark = xstats->ecn - xstats_base->prob_mark;
-	res->pdrop = xstats->tail_drop[tclass_num] - xstats_base->pdrop;
+	early_drops = xstats->wred_drop[tclass_num] - xstats_base->prob_drop;
+	marks = xstats->ecn - xstats_base->prob_mark;
+	pdrops = xstats->tail_drop[tclass_num] - xstats_base->pdrop;
+
+	res->pdrop += pdrops;
+	res->prob_drop += early_drops;
+	res->prob_mark += marks;
+
+	xstats_base->pdrop += pdrops;
+	xstats_base->prob_drop += early_drops;
+	xstats_base->prob_mark += marks;
 	return 0;
 }
 
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -342,32 +342,24 @@ static int red_dump_stats(struct Qdisc *
 {
 	struct red_sched_data *q = qdisc_priv(sch);
 	struct net_device *dev = qdisc_dev(sch);
-	struct tc_red_xstats st = {
-		.early	= q->stats.prob_drop + q->stats.forced_drop,
-		.pdrop	= q->stats.pdrop,
-		.other	= q->stats.other,
-		.marked	= q->stats.prob_mark + q->stats.forced_mark,
-	};
+	struct tc_red_xstats st = {0};
 
 	if (sch->flags & TCQ_F_OFFLOADED) {
-		struct red_stats hw_stats = {0};
 		struct tc_red_qopt_offload hw_stats_request = {
 			.command = TC_RED_XSTATS,
 			.handle = sch->handle,
 			.parent = sch->parent,
 			{
-				.xstats = &hw_stats,
+				.xstats = &q->stats,
 			},
 		};
-		if (!dev->netdev_ops->ndo_setup_tc(dev,
-						   TC_SETUP_QDISC_RED,
-						   &hw_stats_request)) {
-			st.early += hw_stats.prob_drop + hw_stats.forced_drop;
-			st.pdrop += hw_stats.pdrop;
-			st.other += hw_stats.other;
-			st.marked += hw_stats.prob_mark + hw_stats.forced_mark;
-		}
+		dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
+					      &hw_stats_request);
 	}
+	st.early = q->stats.prob_drop + q->stats.forced_drop;
+	st.pdrop = q->stats.pdrop;
+	st.other = q->stats.other;
+	st.marked = q->stats.prob_mark + q->stats.forced_mark;
 
 	return gnet_stats_copy_app(d, &st, sizeof(st));
 }