Re: [RFC PATCH net-next v4 4/6] ice: Implement devlink-rate API

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

From:   Michal Wilczynski <michal.wilczynski@intel.com>
Date:   Thu, 15 Sep 2022 15:42:37 +0200

> There is a need to support modification of Tx scheduler topology, in the
> ice driver. This will allow user to control Tx settings of each node in
> the internal hierarchy of nodes. A number of parameters is supported per
> each node: tx_max, tx_share, tx_priority and tx_weight.
> 
> Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_devlink.c | 511 +++++++++++++++++++
>  drivers/net/ethernet/intel/ice/ice_devlink.h |   2 +
>  2 files changed, 513 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_devlink.c b/drivers/net/ethernet/intel/ice/ice_devlink.c
> index e6ec20079ced..925283605b59 100644
> --- a/drivers/net/ethernet/intel/ice/ice_devlink.c
> +++ b/drivers/net/ethernet/intel/ice/ice_devlink.c
> @@ -713,6 +713,490 @@ ice_devlink_port_unsplit(struct devlink *devlink, struct devlink_port *port,
>  	return ice_devlink_port_split(devlink, port, 1, extack);
>  }
>  
> +/**
> + * ice_traverse_tx_tree - traverse Tx scheduler tree
> + * @devlink: devlink struct
> + * @node: current node, used for recursion
> + * @tc_node: tc_node struct, that is treated as a root
> + * @pf: pf struct
> + *
> + * This function traverses Tx scheduler tree and exports
> + * entire structure to the devlink-rate.
> + */
> +static void ice_traverse_tx_tree(struct devlink *devlink, struct ice_sched_node *node,
> +				 struct ice_sched_node *tc_node, struct ice_pf *pf)
> +{
> +	struct ice_vf *vf;
> +	int i;
> +
> +	devl_lock(devlink);
> +
> +	if (node->parent == tc_node) {
> +		/* create root node */
> +		devl_rate_node_create(devlink, node, node->name, NULL);
> +	} else if (node->info.data.elem_type == ICE_AQC_ELEM_TYPE_LEAF &&
> +		   node->parent->name) {
> +		devl_rate_queue_create(devlink, node->parent->name, node->tx_queue_id, node);
> +	} else if (node->vsi_handle &&
> +		   pf->vsi[node->vsi_handle]->vf) {
> +		vf = pf->vsi[node->vsi_handle]->vf;
> +		snprintf(node->name, DEVLINK_RATE_NAME_MAX_LEN, "vport_%u", vf->devlink_port.index);
> +		if (!vf->devlink_port.devlink_rate)
> +			devl_rate_vport_create(&vf->devlink_port, node, node->parent->name);
> +	} else {
> +		devl_rate_node_create(devlink, node, node->name, node->parent->name);
> +	}
> +
> +	devl_unlock(devlink);

I would move devlink locking into ice_devlink_rate_init_tx_topology(),
so it would be locked only once for the whole tree walking.

> +
> +	for (i = 0; i < node->num_children; i++)
> +		ice_traverse_tx_tree(devlink, node->children[i], tc_node, pf);
> +}
> +
> +/**
> + * ice_devlink_rate_init_tx_topology - export Tx scheduler tree to devlink rate
> + * @devlink: devlink struct
> + * @vsi: main vsi struct
> + *
> + * This function finds a root node, then calls ice_traverse_tx tree, which
> + * traverses the tree and export it's contents to devlink rate.
> + */
> +int ice_devlink_rate_init_tx_topology(struct devlink *devlink, struct ice_vsi *vsi)
> +{
> +	struct ice_port_info *pi = vsi->port_info;
> +	struct ice_sched_node *tc_node;
> +	struct ice_pf *pf = vsi->back;
> +	int i;
> +
> +	tc_node = pi->root->children[0];
> +	mutex_lock(&pi->sched_lock);
> +	for (i = 0; i < tc_node->num_children; i++)
> +		ice_traverse_tx_tree(devlink, tc_node->children[i], tc_node, pf);
> +	mutex_unlock(&pi->sched_lock);
> +
> +	return 0;
> +}

// snip

>  static int
> @@ -893,6 +1399,9 @@ void ice_devlink_register(struct ice_pf *pf)
>   */
>  void ice_devlink_unregister(struct ice_pf *pf)
>  {
> +	devl_lock(priv_to_devlink(pf));
> +	devl_rate_objects_destroy(priv_to_devlink(pf));
> +	devl_unlock(priv_to_devlink(pf));
>  	devlink_unregister(priv_to_devlink(pf));
>  }
>

Maybe it's now worth a variable for priv_to_devlink(pf)?

[...]

--Przemek