net/mlx5e: kTLS, Add debugfs

Add TLS debugfs to improve observability by exposing the size of the tls
TX pool.

To observe the size of the TX pool:
$ cat /sys/kernel/debug/mlx5/<pci>/nic/tls/tx/pool_size
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Co-developed-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls.c

 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
 // Copyright (c) 2019 Mellanox Technologies.
 
+#include <linux/debugfs.h>
 #include "en.h"
 #include "lib/mlx5.h"
 #include "en_accel/ktls.h"
@@ -177,6 +178,15 @@ void mlx5e_ktls_cleanup_rx(struct mlx5e_priv *priv)
 	destroy_workqueue(priv->tls->rx_wq);
 }
 
+static void mlx5e_tls_debugfs_init(struct mlx5e_tls *tls,
+				   struct dentry *dfs_root)
+{
+	if (IS_ERR_OR_NULL(dfs_root))
+		return;
+
+	tls->debugfs.dfs = debugfs_create_dir("tls", dfs_root);
+}
+
 int mlx5e_ktls_init(struct mlx5e_priv *priv)
 {
 	struct mlx5e_tls *tls;
@@ -189,11 +199,23 @@ int mlx5e_ktls_init(struct mlx5e_priv *priv)
 		return -ENOMEM;
 
 	priv->tls = tls;
+	priv->tls->mdev = priv->mdev;
+
+	mlx5e_tls_debugfs_init(tls, priv->dfs_root);
+
 	return 0;
 }
 
 void mlx5e_ktls_cleanup(struct mlx5e_priv *priv)
 {
+	struct mlx5e_tls *tls = priv->tls;
+
+	if (!mlx5e_is_ktls_device(priv->mdev))
+		return;
+
+	debugfs_remove_recursive(tls->debugfs.dfs);
+	tls->debugfs.dfs = NULL;
+
 	kfree(priv->tls);
 	priv->tls = NULL;
 }

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls.h

@@ -4,6 +4,7 @@
 #ifndef __MLX5E_KTLS_H__
 #define __MLX5E_KTLS_H__
 
+#include <linux/debugfs.h>
 #include <linux/tls.h>
 #include <net/tls.h>
 #include "en.h"
@@ -72,10 +73,17 @@ struct mlx5e_tls_sw_stats {
 	atomic64_t rx_tls_del;
 };
 
+struct mlx5e_tls_debugfs {
+	struct dentry *dfs;
+	struct dentry *dfs_tx;
+};
+
 struct mlx5e_tls {
+	struct mlx5_core_dev *mdev;
 	struct mlx5e_tls_sw_stats sw_stats;
 	struct workqueue_struct *rx_wq;
 	struct mlx5e_tls_tx_pool *tx_pool;
+	struct mlx5e_tls_debugfs debugfs;
 };
 
 int mlx5e_ktls_init(struct mlx5e_priv *priv);

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c

 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
 // Copyright (c) 2019 Mellanox Technologies.
 
+#include <linux/debugfs.h>
 #include "en_accel/ktls.h"
 #include "en_accel/ktls_txrx.h"
 #include "en_accel/ktls_utils.h"
@@ -886,8 +887,24 @@ bool mlx5e_ktls_handle_tx_skb(struct net_device *netdev, struct mlx5e_txqsq *sq,
 	return false;
 }
 
+static void mlx5e_tls_tx_debugfs_init(struct mlx5e_tls *tls,
+				      struct dentry *dfs_root)
+{
+	if (IS_ERR_OR_NULL(dfs_root))
+		return;
+
+	tls->debugfs.dfs_tx = debugfs_create_dir("tx", dfs_root);
+	if (!tls->debugfs.dfs_tx)
+		return;
+
+	debugfs_create_size_t("pool_size", 0400, tls->debugfs.dfs_tx,
+			      &tls->tx_pool->size);
+}
+
 int mlx5e_ktls_init_tx(struct mlx5e_priv *priv)
 {
+	struct mlx5e_tls *tls = priv->tls;
+
 	if (!mlx5e_is_ktls_tx(priv->mdev))
 		return 0;
 
@@ -895,6 +912,8 @@ int mlx5e_ktls_init_tx(struct mlx5e_priv *priv)
 	if (!priv->tls->tx_pool)
 		return -ENOMEM;
 
+	mlx5e_tls_tx_debugfs_init(tls, tls->debugfs.dfs);
+
 	return 0;
 }
 
@@ -903,6 +922,9 @@ void mlx5e_ktls_cleanup_tx(struct mlx5e_priv *priv)
 	if (!mlx5e_is_ktls_tx(priv->mdev))
 		return;
 
+	debugfs_remove_recursive(priv->tls->debugfs.dfs_tx);
+	priv->tls->debugfs.dfs_tx = NULL;
+
 	mlx5e_tls_tx_pool_cleanup(priv->tls->tx_pool);
 	priv->tls->tx_pool = NULL;
 }