net/mlx5: Remove default QoS group and attach vports directly to root TSAR

Currently, the driver creates a default group (`node0`) and attaches
all vports to it unless the user explicitly sets a parent group. As a
result, when a user configures tx_share on a group and tx_share on
a VF, the expectation is for the group and the VF to share bandwidth
relatively. However, since the VF is not connected to the same parent
(but to the default node), the proportional share logic is not applied
correctly.

To fix this, remove the default group (`node0`) and instead connect
vports directly to the root TSAR when no parent is specified. This
ensures that vports and groups share the same root scheduler and their
tx_share values are compared directly under the same hierarchy.

Fixes: 0fe132e ("net/mlx5: E-switch, Allow to add vports to rate groups")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250820133209.389065-3-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: cjubran

drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c

@@ -462,6 +462,7 @@ static int
 esw_qos_vport_create_sched_element(struct mlx5_esw_sched_node *vport_node,
 				   struct netlink_ext_ack *extack)
 {
+	struct mlx5_esw_sched_node *parent = vport_node->parent;
 	u32 sched_ctx[MLX5_ST_SZ_DW(scheduling_context)] = {};
 	struct mlx5_core_dev *dev = vport_node->esw->dev;
 	void *attr;
@@ -477,7 +478,7 @@ esw_qos_vport_create_sched_element(struct mlx5_esw_sched_node *vport_node,
 	attr = MLX5_ADDR_OF(scheduling_context, sched_ctx, element_attributes);
 	MLX5_SET(vport_element, attr, vport_number, vport_node->vport->vport);
 	MLX5_SET(scheduling_context, sched_ctx, parent_element_id,
-		 vport_node->parent->ix);
+		 parent ? parent->ix : vport_node->esw->qos.root_tsar_ix);
 	MLX5_SET(scheduling_context, sched_ctx, max_average_bw,
 		 vport_node->max_rate);
 
@@ -786,48 +787,15 @@ static int esw_qos_create(struct mlx5_eswitch *esw, struct netlink_ext_ack *exta
 		return err;
 	}
 
-	if (MLX5_CAP_QOS(dev, log_esw_max_sched_depth)) {
-		esw->qos.node0 = __esw_qos_create_vports_sched_node(esw, NULL, extack);
-	} else {
-		/* The eswitch doesn't support scheduling nodes.
-		 * Create a software-only node0 using the root TSAR to attach vport QoS to.
-		 */
-		if (!__esw_qos_alloc_node(esw,
-					  esw->qos.root_tsar_ix,
-					  SCHED_NODE_TYPE_VPORTS_TSAR,
-					  NULL))
-			esw->qos.node0 = ERR_PTR(-ENOMEM);
-		else
-			list_add_tail(&esw->qos.node0->entry,
-				      &esw->qos.domain->nodes);
-	}
-	if (IS_ERR(esw->qos.node0)) {
-		err = PTR_ERR(esw->qos.node0);
-		esw_warn(dev, "E-Switch create rate node 0 failed (%d)\n", err);
-		goto err_node0;
-	}
 	refcount_set(&esw->qos.refcnt, 1);
 
 	return 0;
-
-err_node0:
-	if (mlx5_destroy_scheduling_element_cmd(esw->dev, SCHEDULING_HIERARCHY_E_SWITCH,
-						esw->qos.root_tsar_ix))
-		esw_warn(esw->dev, "E-Switch destroy root TSAR failed.\n");
-
-	return err;
 }
 
 static void esw_qos_destroy(struct mlx5_eswitch *esw)
 {
 	int err;
 
-	if (esw->qos.node0->ix != esw->qos.root_tsar_ix)
-		__esw_qos_destroy_node(esw->qos.node0, NULL);
-	else
-		__esw_qos_free_node(esw->qos.node0);
-	esw->qos.node0 = NULL;
-
 	err = mlx5_destroy_scheduling_element_cmd(esw->dev,
 						  SCHEDULING_HIERARCHY_E_SWITCH,
 						  esw->qos.root_tsar_ix);
@@ -990,13 +958,16 @@ esw_qos_vport_tc_enable(struct mlx5_vport *vport, enum sched_node_type type,
 			struct netlink_ext_ack *extack)
 {
 	struct mlx5_esw_sched_node *vport_node = vport->qos.sched_node;
-	int err, new_level, max_level;
+	struct mlx5_esw_sched_node *parent = vport_node->parent;
+	int err;
 
 	if (type == SCHED_NODE_TYPE_TC_ARBITER_TSAR) {
+		int new_level, max_level;
+
 		/* Increase the parent's level by 2 to account for both the
 		 * TC arbiter and the vports TC scheduling element.
 		 */
-		new_level = vport_node->parent->level + 2;
+		new_level = (parent ? parent->level : 2) + 2;
 		max_level = 1 << MLX5_CAP_QOS(vport_node->esw->dev,
 					      log_esw_max_sched_depth);
 		if (new_level > max_level) {
@@ -1033,9 +1004,7 @@ esw_qos_vport_tc_enable(struct mlx5_vport *vport, enum sched_node_type type,
 err_sched_nodes:
 	if (type == SCHED_NODE_TYPE_RATE_LIMITER) {
 		esw_qos_node_destroy_sched_element(vport_node, NULL);
-		list_add_tail(&vport_node->entry,
-			      &vport_node->parent->children);
-		vport_node->level = vport_node->parent->level + 1;
+		esw_qos_node_attach_to_parent(vport_node);
 	} else {
 		esw_qos_tc_arbiter_scheduling_teardown(vport_node, NULL);
 	}
@@ -1083,7 +1052,6 @@ static int esw_qos_set_vport_tcs_min_rate(struct mlx5_vport *vport,
 static void esw_qos_vport_disable(struct mlx5_vport *vport, struct netlink_ext_ack *extack)
 {
 	struct mlx5_esw_sched_node *vport_node = vport->qos.sched_node;
-	struct mlx5_esw_sched_node *parent = vport_node->parent;
 	enum sched_node_type curr_type = vport_node->type;
 
 	if (curr_type == SCHED_NODE_TYPE_VPORT)
@@ -1093,7 +1061,7 @@ static void esw_qos_vport_disable(struct mlx5_vport *vport, struct netlink_ext_a
 
 	vport_node->bw_share = 0;
 	list_del_init(&vport_node->entry);
-	esw_qos_normalize_min_rate(parent->esw, parent, extack);
+	esw_qos_normalize_min_rate(vport_node->esw, vport_node->parent, extack);
 
 	trace_mlx5_esw_vport_qos_destroy(vport_node->esw->dev, vport);
 }
@@ -1103,25 +1071,23 @@ static int esw_qos_vport_enable(struct mlx5_vport *vport,
 				struct mlx5_esw_sched_node *parent,
 				struct netlink_ext_ack *extack)
 {
+	struct mlx5_esw_sched_node *vport_node = vport->qos.sched_node;
 	int err;
 
 	esw_assert_qos_lock_held(vport->dev->priv.eswitch);
 
-	esw_qos_node_set_parent(vport->qos.sched_node, parent);
-	if (type == SCHED_NODE_TYPE_VPORT) {
-		err = esw_qos_vport_create_sched_element(vport->qos.sched_node,
-							 extack);
-	} else {
+	esw_qos_node_set_parent(vport_node, parent);
+	if (type == SCHED_NODE_TYPE_VPORT)
+		err = esw_qos_vport_create_sched_element(vport_node, extack);
+	else
 		err = esw_qos_vport_tc_enable(vport, type, extack);
-	}
 	if (err)
 		return err;
 
-	vport->qos.sched_node->type = type;
-	esw_qos_normalize_min_rate(parent->esw, parent, extack);
-	trace_mlx5_esw_vport_qos_create(vport->dev, vport,
-					vport->qos.sched_node->max_rate,
-					vport->qos.sched_node->bw_share);
+	vport_node->type = type;
+	esw_qos_normalize_min_rate(vport_node->esw, parent, extack);
+	trace_mlx5_esw_vport_qos_create(vport->dev, vport, vport_node->max_rate,
+					vport_node->bw_share);
 
 	return 0;
 }
@@ -1132,17 +1098,20 @@ static int mlx5_esw_qos_vport_enable(struct mlx5_vport *vport, enum sched_node_t
 {
 	struct mlx5_eswitch *esw = vport->dev->priv.eswitch;
 	struct mlx5_esw_sched_node *sched_node;
+	struct mlx5_eswitch *parent_esw;
 	int err;
 
 	esw_assert_qos_lock_held(esw);
 	err = esw_qos_get(esw, extack);
 	if (err)
 		return err;
 
-	parent = parent ?: esw->qos.node0;
-	sched_node = __esw_qos_alloc_node(parent->esw, 0, type, parent);
+	parent_esw = parent ? parent->esw : esw;
+	sched_node = __esw_qos_alloc_node(parent_esw, 0, type, parent);
 	if (!sched_node)
 		return -ENOMEM;
+	if (!parent)
+		list_add_tail(&sched_node->entry, &esw->qos.domain->nodes);
 
 	sched_node->max_rate = max_rate;
 	sched_node->min_rate = min_rate;
@@ -1168,7 +1137,7 @@ void mlx5_esw_qos_vport_disable(struct mlx5_vport *vport)
 		goto unlock;
 
 	parent = vport->qos.sched_node->parent;
-	WARN(parent != esw->qos.node0, "Disabling QoS on port before detaching it from node");
+	WARN(parent, "Disabling QoS on port before detaching it from node");
 
 	esw_qos_vport_disable(vport, NULL);
 	mlx5_esw_qos_vport_qos_free(vport);
@@ -1268,7 +1237,6 @@ static int esw_qos_vport_update(struct mlx5_vport *vport,
 	int err;
 
 	esw_assert_qos_lock_held(vport->dev->priv.eswitch);
-	parent = parent ?: curr_parent;
 	if (curr_type == type && curr_parent == parent)
 		return 0;
 
@@ -1306,16 +1274,16 @@ static int esw_qos_vport_update_parent(struct mlx5_vport *vport, struct mlx5_esw
 
 	esw_assert_qos_lock_held(esw);
 	curr_parent = vport->qos.sched_node->parent;
-	parent = parent ?: esw->qos.node0;
 	if (curr_parent == parent)
 		return 0;
 
 	/* Set vport QoS type based on parent node type if different from
 	 * default QoS; otherwise, use the vport's current QoS type.
 	 */
-	if (parent->type == SCHED_NODE_TYPE_TC_ARBITER_TSAR)
+	if (parent && parent->type == SCHED_NODE_TYPE_TC_ARBITER_TSAR)
 		type = SCHED_NODE_TYPE_RATE_LIMITER;
-	else if (curr_parent->type == SCHED_NODE_TYPE_TC_ARBITER_TSAR)
+	else if (curr_parent &&
+		 curr_parent->type == SCHED_NODE_TYPE_TC_ARBITER_TSAR)
 		type = SCHED_NODE_TYPE_VPORT;
 	else
 		type = vport->qos.sched_node->type;
@@ -1654,9 +1622,10 @@ static bool esw_qos_validate_unsupported_tc_bw(struct mlx5_eswitch *esw,
 static bool esw_qos_vport_validate_unsupported_tc_bw(struct mlx5_vport *vport,
 						     u32 *tc_bw)
 {
-	struct mlx5_eswitch *esw = vport->qos.sched_node ?
-				   vport->qos.sched_node->parent->esw :
-				   vport->dev->priv.eswitch;
+	struct mlx5_esw_sched_node *node = vport->qos.sched_node;
+	struct mlx5_eswitch *esw = vport->dev->priv.eswitch;
+
+	esw = (node && node->parent) ? node->parent->esw : esw;
 
 	return esw_qos_validate_unsupported_tc_bw(esw, tc_bw);
 }
@@ -1763,7 +1732,7 @@ int mlx5_esw_devlink_rate_leaf_tc_bw_set(struct devlink_rate *rate_leaf,
 	if (disable) {
 		if (vport_node->type == SCHED_NODE_TYPE_TC_ARBITER_TSAR)
 			err = esw_qos_vport_update(vport, SCHED_NODE_TYPE_VPORT,
-						   NULL, extack);
+						   vport_node->parent, extack);
 		goto unlock;
 	}
 
@@ -1775,7 +1744,7 @@ int mlx5_esw_devlink_rate_leaf_tc_bw_set(struct devlink_rate *rate_leaf,
 	} else {
 		err = esw_qos_vport_update(vport,
 					   SCHED_NODE_TYPE_TC_ARBITER_TSAR,
-					   NULL, extack);
+					   vport_node->parent, extack);
 	}
 	if (!err)
 		esw_qos_set_tc_arbiter_bw_shares(vport_node, tc_bw, extack);

drivers/net/ethernet/mellanox/mlx5/core/eswitch.h

@@ -373,11 +373,6 @@ struct mlx5_eswitch {
 		refcount_t refcnt;
 		u32 root_tsar_ix;
 		struct mlx5_qos_domain *domain;
-		/* Contains all vports with QoS enabled but no explicit node.
-		 * Cannot be NULL if QoS is enabled, but may be a fake node
-		 * referencing the root TSAR if the esw doesn't support nodes.
-		 */
-		struct mlx5_esw_sched_node *node0;
 	} qos;
 
 	struct mlx5_esw_bridge_offloads *br_offloads;