mlxsw: spectrum: Support general qdisc stats

Add support for ndo_setup_tc with enum tc_setup_type value of
TC_SETUP_QDISC_STATS. This call updates the generic qdisc stats from the
cache if the handle ID that is asked for matching the root qdisc ID and
fails otherwise.
Currently doesn't support qlen and rqueues.
Signed-off-by: Nogah Frankel <nogahf@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.h

@@ -220,6 +220,11 @@ struct mlxsw_sp_qdisc {
 			u64 wred_drop_base;
 		} red;
 	} xstats;
+
+	u64 tx_bytes;
+	u64 tx_packets;
+	u64 drops;
+	u64 overlimits;
 };
 
 /* No need an internal lock; At worse - miss a single periodic iteration */

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

@@ -85,14 +85,24 @@ mlxsw_sp_setup_tc_qdisc_clean_stats(struct mlxsw_sp_port *mlxsw_sp_port,
 {
 	struct red_stats *xstats_base = &mlxsw_sp_qdisc->xstats_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;
+
+	mlxsw_sp_qdisc->tx_packets = stats->tx_packets;
+	mlxsw_sp_qdisc->tx_bytes = stats->tx_bytes;
 
 	switch (mlxsw_sp_qdisc->type) {
 	case MLXSW_SP_QDISC_RED:
 		xstats_base->prob_mark = xstats->ecn;
 		xstats_base->prob_drop = xstats->wred_drop[tclass_num];
 		xstats_base->pdrop = xstats->tail_drop[tclass_num];
+
+		mlxsw_sp_qdisc->overlimits = xstats_base->prob_drop +
+					     xstats_base->prob_mark;
+		mlxsw_sp_qdisc->drops = xstats_base->prob_drop +
+					xstats_base->pdrop;
 		break;
 	default:
 		break;
@@ -193,6 +203,43 @@ mlxsw_sp_qdisc_get_red_xstats(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
 	return 0;
 }
 
+static int
+mlxsw_sp_qdisc_get_red_stats(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
+			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
+			     int tclass_num,
+			     struct tc_red_qopt_offload_stats *res)
+{
+	u64 tx_bytes, tx_packets, overlimits, drops;
+	struct mlxsw_sp_port_xstats *xstats;
+	struct rtnl_link_stats64 *stats;
+
+	if (mlxsw_sp_qdisc->handle != handle ||
+	    mlxsw_sp_qdisc->type != MLXSW_SP_QDISC_RED)
+		return -EOPNOTSUPP;
+
+	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
+	stats = &mlxsw_sp_port->periodic_hw_stats.stats;
+
+	tx_bytes = stats->tx_bytes - mlxsw_sp_qdisc->tx_bytes;
+	tx_packets = stats->tx_packets - mlxsw_sp_qdisc->tx_packets;
+	overlimits = xstats->wred_drop[tclass_num] + xstats->ecn -
+		     mlxsw_sp_qdisc->overlimits;
+	drops = xstats->wred_drop[tclass_num] + xstats->tail_drop[tclass_num] -
+		mlxsw_sp_qdisc->drops;
+
+	_bstats_update(res->bstats, tx_bytes, tx_packets);
+	res->qstats->overlimits += overlimits;
+	res->qstats->drops += drops;
+	res->qstats->backlog += mlxsw_sp_cells_bytes(mlxsw_sp_port->mlxsw_sp,
+						xstats->backlog[tclass_num]);
+
+	mlxsw_sp_qdisc->drops +=  drops;
+	mlxsw_sp_qdisc->overlimits += overlimits;
+	mlxsw_sp_qdisc->tx_bytes += tx_bytes;
+	mlxsw_sp_qdisc->tx_packets += tx_packets;
+	return 0;
+}
+
 #define MLXSW_SP_PORT_DEFAULT_TCLASS 0
 
 int mlxsw_sp_setup_tc_red(struct mlxsw_sp_port *mlxsw_sp_port,
@@ -219,6 +266,10 @@ int mlxsw_sp_setup_tc_red(struct mlxsw_sp_port *mlxsw_sp_port,
 		return mlxsw_sp_qdisc_get_red_xstats(mlxsw_sp_port, p->handle,
 						     mlxsw_sp_qdisc, tclass_num,
 						     p->xstats);
+	case TC_RED_STATS:
+		return mlxsw_sp_qdisc_get_red_stats(mlxsw_sp_port, p->handle,
+						    mlxsw_sp_qdisc, tclass_num,
+						    &p->stats);
 	default:
 		return -EOPNOTSUPP;
 	}