mlxsw: spectrum: qdiscs: Collect stats for sch_red based on priomap

Priority counters count packets according to their packet priority.
Collect the stats for sch_red based on these counters, so the qdisc bstats
will be the sum of counters matching the priorities marked in the qdisc
priomap.
Changing the mapping of the priorities to bands while traffic is running
can result in losing the stats of the bands qdiscs from their last dump
call to this change, as if the qdisc was unoffloaded and re-offloaded. It
will not affect the traffic behaviour according to sch_red.

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>

drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c

@@ -208,6 +208,23 @@ mlxsw_sp_qdisc_get_xstats(struct mlxsw_sp_port *mlxsw_sp_port,
 	return -EOPNOTSUPP;
 }
 
+static void
+mlxsw_sp_qdisc_bstats_per_priority_get(struct mlxsw_sp_port_xstats *xstats,
+				       u8 prio_bitmap, u64 *tx_packets,
+				       u64 *tx_bytes)
+{
+	int i;
+
+	*tx_packets = 0;
+	*tx_bytes = 0;
+	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+		if (prio_bitmap & BIT(i)) {
+			*tx_packets += xstats->tx_packets[i];
+			*tx_bytes += xstats->tx_bytes[i];
+		}
+	}
+}
+
 static int
 mlxsw_sp_tclass_congestion_enable(struct mlxsw_sp_port *mlxsw_sp_port,
 				  int tclass_num, u32 min, u32 max,
@@ -253,17 +270,16 @@ mlxsw_sp_setup_tc_qdisc_red_clean_stats(struct mlxsw_sp_port *mlxsw_sp_port,
 	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
 	struct mlxsw_sp_qdisc_stats *stats_base;
 	struct mlxsw_sp_port_xstats *xstats;
-	struct rtnl_link_stats64 *stats;
 	struct red_stats *red_base;
 
 	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
-	stats = &mlxsw_sp_port->periodic_hw_stats.stats;
 	stats_base = &mlxsw_sp_qdisc->stats_base;
 	red_base = &mlxsw_sp_qdisc->xstats_base.red;
 
-	stats_base->tx_packets = stats->tx_packets;
-	stats_base->tx_bytes = stats->tx_bytes;
-
+	mlxsw_sp_qdisc_bstats_per_priority_get(xstats,
+					       mlxsw_sp_qdisc->prio_bitmap,
+					       &stats_base->tx_packets,
+					       &stats_base->tx_bytes);
 	red_base->prob_mark = xstats->ecn;
 	red_base->prob_drop = xstats->wred_drop[tclass_num];
 	red_base->pdrop = xstats->tail_drop[tclass_num];
@@ -380,14 +396,16 @@ mlxsw_sp_qdisc_get_red_stats(struct mlxsw_sp_port *mlxsw_sp_port,
 	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
 	struct mlxsw_sp_qdisc_stats *stats_base;
 	struct mlxsw_sp_port_xstats *xstats;
-	struct rtnl_link_stats64 *stats;
 
 	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
-	stats = &mlxsw_sp_port->periodic_hw_stats.stats;
 	stats_base = &mlxsw_sp_qdisc->stats_base;
 
-	tx_bytes = stats->tx_bytes - stats_base->tx_bytes;
-	tx_packets = stats->tx_packets - stats_base->tx_packets;
+	mlxsw_sp_qdisc_bstats_per_priority_get(xstats,
+					       mlxsw_sp_qdisc->prio_bitmap,
+					       &tx_packets, &tx_bytes);
+	tx_bytes = tx_bytes - stats_base->tx_bytes;
+	tx_packets = tx_packets - stats_base->tx_packets;
+
 	overlimits = xstats->wred_drop[tclass_num] + xstats->ecn -
 		     stats_base->overlimits;
 	drops = xstats->wred_drop[tclass_num] + xstats->tail_drop[tclass_num] -
@@ -493,18 +511,31 @@ mlxsw_sp_qdisc_prio_replace(struct mlxsw_sp_port *mlxsw_sp_port,
 			    void *params)
 {
 	struct tc_prio_qopt_offload_params *p = params;
-	int tclass, i;
+	struct mlxsw_sp_qdisc *child_qdisc;
+	int tclass, i, band;
+	u8 old_priomap;
 	int err;
 
-	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++)
-		mlxsw_sp_port->tclass_qdiscs[i].prio_bitmap = 0;
-
-	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
-		tclass = MLXSW_SP_PRIO_BAND_TO_TCLASS(p->priomap[i]);
-		err = mlxsw_sp_port_prio_tc_set(mlxsw_sp_port, i, tclass);
-		if (err)
-			return err;
-		mlxsw_sp_port->tclass_qdiscs[tclass].prio_bitmap |= BIT(i);
+	for (band = 0; band < p->bands; band++) {
+		tclass = MLXSW_SP_PRIO_BAND_TO_TCLASS(band);
+		child_qdisc = &mlxsw_sp_port->tclass_qdiscs[tclass];
+		old_priomap = child_qdisc->prio_bitmap;
+		child_qdisc->prio_bitmap = 0;
+		for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+			if (p->priomap[i] == band) {
+				child_qdisc->prio_bitmap |= BIT(i);
+				if (BIT(i) & old_priomap)
+					continue;
+				err = mlxsw_sp_port_prio_tc_set(mlxsw_sp_port,
+								i, tclass);
+				if (err)
+					return err;
+			}
+		}
+		if (old_priomap != child_qdisc->prio_bitmap &&
+		    child_qdisc->ops && child_qdisc->ops->clean_stats)
+			child_qdisc->ops->clean_stats(mlxsw_sp_port,
+						      child_qdisc);
 	}
 
 	return 0;