ice: update VSI config dynamically

When VSI increases the number of queues dynamically, the scheduler
just needs to add the new required nodes rather than re-adjusting with
previously allocated number of nodes. Readjusting didn't provide enough
parents to add the upper layer nodes also can't place lan and rdma
subtrees separately.

In decrease case, keep the VSI configuration with max number of queues
always. This will leave some extra nodes in the tree but no harm done.
Signed-off-by: Victor Raj <victor.raj@intel.com>
Reviewed-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice_sched.c

@@ -1268,42 +1268,6 @@ ice_sched_add_vsi_child_nodes(struct ice_port_info *pi, u16 vsi_handle,
 	return 0;
 }
 
-/**
- * ice_sched_rm_vsi_child_nodes - remove VSI child nodes from the tree
- * @pi: port information structure
- * @vsi_node: pointer to the VSI node
- * @num_nodes: pointer to the num nodes that needs to be removed per layer
- * @owner: node owner (lan or rdma)
- *
- * This function removes the VSI child nodes from the tree. It gets called for
- * lan and rdma separately.
- */
-static void
-ice_sched_rm_vsi_child_nodes(struct ice_port_info *pi,
-			     struct ice_sched_node *vsi_node, u16 *num_nodes,
-			     u8 owner)
-{
-	struct ice_sched_node *node, *next;
-	u8 i, qgl, vsil;
-	u16 num;
-
-	qgl = ice_sched_get_qgrp_layer(pi->hw);
-	vsil = ice_sched_get_vsi_layer(pi->hw);
-
-	for (i = qgl; i > vsil; i--) {
-		num = num_nodes[i];
-		node = ice_sched_get_first_node(pi->hw, vsi_node, i);
-		while (node && num) {
-			next = node->sibling;
-			if (node->owner == owner && !node->num_children) {
-				ice_free_sched_node(pi, node);
-				num--;
-			}
-			node = next;
-		}
-	}
-}
-
 /**
  * ice_sched_calc_vsi_support_nodes - calculate number of VSI support nodes
  * @hw: pointer to the hw struct
@@ -1444,7 +1408,6 @@ static enum ice_status
 ice_sched_update_vsi_child_nodes(struct ice_port_info *pi, u16 vsi_handle,
 				 u8 tc, u16 new_numqs, u8 owner)
 {
-	u16 prev_num_nodes[ICE_AQC_TOPO_MAX_LEVEL_NUM] = { 0 };
 	u16 new_num_nodes[ICE_AQC_TOPO_MAX_LEVEL_NUM] = { 0 };
 	struct ice_sched_node *vsi_node;
 	struct ice_sched_node *tc_node;
@@ -1452,7 +1415,6 @@ ice_sched_update_vsi_child_nodes(struct ice_port_info *pi, u16 vsi_handle,
 	enum ice_status status = 0;
 	struct ice_hw *hw = pi->hw;
 	u16 prev_numqs;
-	u8 i;
 
 	tc_node = ice_sched_get_tc_node(pi, tc);
 	if (!tc_node)
@@ -1471,33 +1433,22 @@ ice_sched_update_vsi_child_nodes(struct ice_port_info *pi, u16 vsi_handle,
 	else
 		return ICE_ERR_PARAM;
 
-	/* num queues are not changed */
-	if (prev_numqs == new_numqs)
+	/* num queues are not changed or less than the previous number */
+	if (new_numqs <= prev_numqs)
 		return status;
-
-	/* calculate number of nodes based on prev/new number of qs */
-	if (prev_numqs)
-		ice_sched_calc_vsi_child_nodes(hw, prev_numqs, prev_num_nodes);
-
 	if (new_numqs)
 		ice_sched_calc_vsi_child_nodes(hw, new_numqs, new_num_nodes);
-
-	if (prev_numqs > new_numqs) {
-		for (i = 0; i < ICE_AQC_TOPO_MAX_LEVEL_NUM; i++)
-			new_num_nodes[i] = prev_num_nodes[i] - new_num_nodes[i];
-
-		ice_sched_rm_vsi_child_nodes(pi, vsi_node, new_num_nodes,
-					     owner);
-	} else {
-		for (i = 0; i < ICE_AQC_TOPO_MAX_LEVEL_NUM; i++)
-			new_num_nodes[i] -= prev_num_nodes[i];
-
+	/* Keep the max number of queue configuration all the time. Update the
+	 * tree only if number of queues > previous number of queues. This may
+	 * leave some extra nodes in the tree if number of queues < previous
+	 * number but that wouldn't harm anything. Removing those extra nodes
+	 * may complicate the code if those nodes are part of SRL or
+	 * individually rate limited.
+	 */
 	status = ice_sched_add_vsi_child_nodes(pi, vsi_handle, tc_node,
 					       new_num_nodes, owner);
 	if (status)
 		return status;
-	}
-
 	vsi_ctx->sched.max_lanq[tc] = new_numqs;
 
 	return 0;