net/mlx5e: Add bond_metadata and its slave entries

Adding bond_metadata and its slave entries to represent a lag device
and its slaves VF representors. Bond_metadata structure includes a
unique metadata shared by slaves VF respresentors, and a list of slaves
representors slave entries.

On enslaving event, create a bond_metadata structure representing
the upper lag device of this slave representor if it has not been
created yet. Create and add entry for the slave representor to the
slaves list.

On unslaving event, free the slave entry of the slave representor.
On the last unslave event, free the bond_metadata structure and its
resources.

Introduce APIs to create and remove bond_metadata and its resources,
enslave and unslave VF representor slave entries.
Signed-off-by: Vu Pham <vuhuong@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en/rep/bond.c

 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
 /* Copyright (c) 2020 Mellanox Technologies Inc. All rights reserved. */
 
+#include <linux/netdevice.h>
+#include <linux/list.h>
 #include <net/lag.h>
 
 #include "mlx5_core.h"
@@ -11,8 +13,132 @@
 struct mlx5e_rep_bond {
 	struct notifier_block nb;
 	struct netdev_net_notifier nn;
+	struct list_head metadata_list;
 };
 
+struct mlx5e_rep_bond_slave_entry {
+	struct list_head list;
+	struct net_device *netdev;
+};
+
+struct mlx5e_rep_bond_metadata {
+	struct list_head list; /* link to global list of rep_bond_metadata */
+	struct mlx5_eswitch *esw;
+	 /* private of uplink holding rep bond metadata list */
+	struct net_device *lag_dev;
+	u32 metadata_reg_c_0;
+
+	struct list_head slaves_list; /* slaves list */
+	int slaves;
+};
+
+static struct mlx5e_rep_bond_metadata *
+mlx5e_lookup_rep_bond_metadata(struct mlx5_rep_uplink_priv *uplink_priv,
+			       const struct net_device *lag_dev)
+{
+	struct mlx5e_rep_bond_metadata *found = NULL;
+	struct mlx5e_rep_bond_metadata *cur;
+
+	list_for_each_entry(cur, &uplink_priv->bond->metadata_list, list) {
+		if (cur->lag_dev == lag_dev) {
+			found = cur;
+			break;
+		}
+	}
+
+	return found;
+}
+
+static struct mlx5e_rep_bond_slave_entry *
+mlx5e_lookup_rep_bond_slave_entry(struct mlx5e_rep_bond_metadata *mdata,
+				  const struct net_device *netdev)
+{
+	struct mlx5e_rep_bond_slave_entry *found = NULL;
+	struct mlx5e_rep_bond_slave_entry *cur;
+
+	list_for_each_entry(cur, &mdata->slaves_list, list) {
+		if (cur->netdev == netdev) {
+			found = cur;
+			break;
+		}
+	}
+
+	return found;
+}
+
+static void mlx5e_rep_bond_metadata_release(struct mlx5e_rep_bond_metadata *mdata)
+{
+	netdev_dbg(mdata->lag_dev, "destroy rep_bond_metadata(%d)\n",
+		   mdata->metadata_reg_c_0);
+	list_del(&mdata->list);
+	WARN_ON(!list_empty(&mdata->slaves_list));
+	kfree(mdata);
+}
+
+/* This must be called under rtnl_lock */
+int mlx5e_rep_bond_enslave(struct mlx5_eswitch *esw, struct net_device *netdev,
+			   struct net_device *lag_dev)
+{
+	struct mlx5e_rep_bond_slave_entry *s_entry;
+	struct mlx5e_rep_bond_metadata *mdata;
+	struct mlx5e_rep_priv *rpriv;
+
+	ASSERT_RTNL();
+
+	rpriv = mlx5_eswitch_get_uplink_priv(esw, REP_ETH);
+	mdata = mlx5e_lookup_rep_bond_metadata(&rpriv->uplink_priv, lag_dev);
+	if (!mdata) {
+		/* First netdev becomes slave, no metadata presents the lag_dev. Create one */
+		mdata = kzalloc(sizeof(*mdata), GFP_KERNEL);
+		if (!mdata)
+			return -ENOMEM;
+
+		mdata->lag_dev = lag_dev;
+		mdata->esw = esw;
+		INIT_LIST_HEAD(&mdata->slaves_list);
+		list_add(&mdata->list, &rpriv->uplink_priv.bond->metadata_list);
+
+		netdev_dbg(lag_dev, "create rep_bond_metadata(%d)\n",
+			   mdata->metadata_reg_c_0);
+	}
+
+	s_entry = kzalloc(sizeof(*s_entry), GFP_KERNEL);
+	if (!s_entry)
+		return -ENOMEM;
+
+	s_entry->netdev = netdev;
+	mdata->slaves++;
+	list_add_tail(&s_entry->list, &mdata->slaves_list);
+
+	return 0;
+}
+
+/* This must be called under rtnl_lock */
+void mlx5e_rep_bond_unslave(struct mlx5_eswitch *esw,
+			    const struct net_device *netdev,
+			    const struct net_device *lag_dev)
+{
+	struct mlx5e_rep_bond_slave_entry *s_entry;
+	struct mlx5e_rep_bond_metadata *mdata;
+	struct mlx5e_rep_priv *rpriv;
+
+	ASSERT_RTNL();
+
+	rpriv = mlx5_eswitch_get_uplink_priv(esw, REP_ETH);
+	mdata = mlx5e_lookup_rep_bond_metadata(&rpriv->uplink_priv, lag_dev);
+	if (!mdata)
+		return;
+
+	s_entry = mlx5e_lookup_rep_bond_slave_entry(mdata, netdev);
+	if (!s_entry)
+		return;
+
+	list_del(&s_entry->list);
+	if (--mdata->slaves == 0)
+		mlx5e_rep_bond_metadata_release(mdata);
+	kfree(s_entry);
+}
+
 static bool mlx5e_rep_is_lag_netdev(struct net_device *netdev)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
@@ -133,6 +259,7 @@ int mlx5e_rep_bond_init(struct mlx5e_rep_priv *rpriv)
 		goto out;
 	}
 
+	INIT_LIST_HEAD(&uplink_priv->bond->metadata_list);
 	uplink_priv->bond->nb.notifier_call = mlx5e_rep_esw_bond_netevent;
 	ret = register_netdevice_notifier_dev_net(netdev,
 						  &uplink_priv->bond->nb,
@@ -142,6 +269,7 @@ int mlx5e_rep_bond_init(struct mlx5e_rep_priv *rpriv)
 		kvfree(uplink_priv->bond);
 		uplink_priv->bond = NULL;
 	}
+
 out:
 	return ret;
 }

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

@@ -217,6 +217,11 @@ void mlx5e_rep_register_vport_reps(struct mlx5_core_dev *mdev);
 void mlx5e_rep_unregister_vport_reps(struct mlx5_core_dev *mdev);
 int mlx5e_rep_bond_init(struct mlx5e_rep_priv *rpriv);
 void mlx5e_rep_bond_cleanup(struct mlx5e_rep_priv *rpriv);
+int mlx5e_rep_bond_enslave(struct mlx5_eswitch *esw, struct net_device *netdev,
+			   struct net_device *lag_dev);
+void mlx5e_rep_bond_unslave(struct mlx5_eswitch *esw,
+			    const struct net_device *netdev,
+			    const struct net_device *lag_dev);
 
 bool mlx5e_is_uplink_rep(struct mlx5e_priv *priv);
 int mlx5e_add_sqs_fwd_rules(struct mlx5e_priv *priv);