net/mlx5e: TC, Add sampler object API

In order to offload sample action, HW introduces sampler object. The
sampler object samples packets according to the provided sample ratio.
Sampled packets are duplicated. One copy is processed by a termination
table, named the sample table, which sends the packet up to software.
The second copy is processed by the default table.

Instantiate sampler object. Re-use identical sampler object for
the same sample ratio, sample table and default table as a prestep for
offloading tc sample actions.

Signed-off-by: Chris Mi <cmi@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

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

@@ -3,11 +3,28 @@
 
 #include "esw/sample.h"
 #include "eswitch.h"
+#include "en_tc.h"
+#include "fs_core.h"
 
 struct mlx5_esw_psample {
 	struct mlx5e_priv *priv;
 	struct mlx5_flow_table *termtbl;
 	struct mlx5_flow_handle *termtbl_rule;
+	DECLARE_HASHTABLE(hashtbl, 8);
+	struct mutex ht_lock; /* protect hashtbl */
+};
+
+struct mlx5_sampler {
+	struct hlist_node hlist;
+	u32 sampler_id;
+	u32 sample_ratio;
+	u32 sample_table_id;
+	u32 default_table_id;
+	int count;
+};
+
+struct mlx5_sample_flow {
+	struct mlx5_sampler *sampler;
 };
 
 static int
@@ -64,6 +81,117 @@ sampler_termtbl_destroy(struct mlx5_esw_psample *esw_psample)
 	mlx5_destroy_flow_table(esw_psample->termtbl);
 }
 
+static int
+sampler_obj_create(struct mlx5_core_dev *mdev, struct mlx5_sampler *sampler)
+{
+	u32 in[MLX5_ST_SZ_DW(create_sampler_obj_in)] = {};
+	u32 out[MLX5_ST_SZ_DW(general_obj_out_cmd_hdr)];
+	u64 general_obj_types;
+	void *obj;
+	int err;
+
+	general_obj_types = MLX5_CAP_GEN_64(mdev, general_obj_types);
+	if (!(general_obj_types & MLX5_HCA_CAP_GENERAL_OBJECT_TYPES_SAMPLER))
+		return -EOPNOTSUPP;
+	if (!MLX5_CAP_ESW_FLOWTABLE_FDB(mdev, ignore_flow_level))
+		return -EOPNOTSUPP;
+
+	obj = MLX5_ADDR_OF(create_sampler_obj_in, in, sampler_object);
+	MLX5_SET(sampler_obj, obj, table_type, FS_FT_FDB);
+	MLX5_SET(sampler_obj, obj, ignore_flow_level, 1);
+	MLX5_SET(sampler_obj, obj, level, 1);
+	MLX5_SET(sampler_obj, obj, sample_ratio, sampler->sample_ratio);
+	MLX5_SET(sampler_obj, obj, sample_table_id, sampler->sample_table_id);
+	MLX5_SET(sampler_obj, obj, default_table_id, sampler->default_table_id);
+	MLX5_SET(general_obj_in_cmd_hdr, in, opcode, MLX5_CMD_OP_CREATE_GENERAL_OBJECT);
+	MLX5_SET(general_obj_in_cmd_hdr, in, obj_type, MLX5_GENERAL_OBJECT_TYPES_SAMPLER);
+
+	err = mlx5_cmd_exec(mdev, in, sizeof(in), out, sizeof(out));
+	if (!err)
+		sampler->sampler_id = MLX5_GET(general_obj_out_cmd_hdr, out, obj_id);
+
+	return err;
+}
+
+static void
+sampler_obj_destroy(struct mlx5_core_dev *mdev, u32 sampler_id)
+{
+	u32 in[MLX5_ST_SZ_DW(general_obj_in_cmd_hdr)] = {};
+	u32 out[MLX5_ST_SZ_DW(general_obj_out_cmd_hdr)];
+
+	MLX5_SET(general_obj_in_cmd_hdr, in, opcode, MLX5_CMD_OP_DESTROY_GENERAL_OBJECT);
+	MLX5_SET(general_obj_in_cmd_hdr, in, obj_type, MLX5_GENERAL_OBJECT_TYPES_SAMPLER);
+	MLX5_SET(general_obj_in_cmd_hdr, in, obj_id, sampler_id);
+
+	mlx5_cmd_exec(mdev, in, sizeof(in), out, sizeof(out));
+}
+
+static u32
+sampler_hash(u32 sample_ratio, u32 default_table_id)
+{
+	return jhash_2words(sample_ratio, default_table_id, 0);
+}
+
+static int
+sampler_cmp(u32 sample_ratio1, u32 default_table_id1, u32 sample_ratio2, u32 default_table_id2)
+{
+	return sample_ratio1 != sample_ratio2 || default_table_id1 != default_table_id2;
+}
+
+static struct mlx5_sampler *
+sampler_get(struct mlx5_esw_psample *esw_psample, u32 sample_ratio, u32 default_table_id)
+{
+	struct mlx5_sampler *sampler;
+	u32 hash_key;
+	int err;
+
+	mutex_lock(&esw_psample->ht_lock);
+	hash_key = sampler_hash(sample_ratio, default_table_id);
+	hash_for_each_possible(esw_psample->hashtbl, sampler, hlist, hash_key)
+		if (!sampler_cmp(sampler->sample_ratio, sampler->default_table_id,
+				 sample_ratio, default_table_id))
+			goto add_ref;
+
+	sampler = kzalloc(sizeof(*sampler), GFP_KERNEL);
+	if (!sampler) {
+		err = -ENOMEM;
+		goto err_alloc;
+	}
+
+	sampler->sample_table_id = esw_psample->termtbl->id;
+	sampler->default_table_id = default_table_id;
+	sampler->sample_ratio = sample_ratio;
+
+	err = sampler_obj_create(esw_psample->priv->mdev, sampler);
+	if (err)
+		goto err_create;
+
+	hash_add(esw_psample->hashtbl, &sampler->hlist, hash_key);
+
+add_ref:
+	sampler->count++;
+	mutex_unlock(&esw_psample->ht_lock);
+	return sampler;
+
+err_create:
+	kfree(sampler);
+err_alloc:
+	mutex_unlock(&esw_psample->ht_lock);
+	return ERR_PTR(err);
+}
+
+static void
+sampler_put(struct mlx5_esw_psample *esw_psample, struct mlx5_sampler *sampler)
+{
+	mutex_lock(&esw_psample->ht_lock);
+	if (--sampler->count == 0) {
+		hash_del(&sampler->hlist);
+		sampler_obj_destroy(esw_psample->priv->mdev, sampler->sampler_id);
+		kfree(sampler);
+	}
+	mutex_unlock(&esw_psample->ht_lock);
+}
+
 struct mlx5_esw_psample *
 mlx5_esw_sample_init(struct mlx5e_priv *priv)
 {
@@ -78,6 +206,8 @@ mlx5_esw_sample_init(struct mlx5e_priv *priv)
 	if (err)
 		goto err_termtbl;
 
+	mutex_init(&esw_psample->ht_lock);
+
 	return esw_psample;
 
 err_termtbl:
@@ -91,6 +221,7 @@ mlx5_esw_sample_cleanup(struct mlx5_esw_psample *esw_psample)
 	if (IS_ERR_OR_NULL(esw_psample))
 		return;
 
+	mutex_destroy(&esw_psample->ht_lock);
 	sampler_termtbl_destroy(esw_psample);
 	kfree(esw_psample);
 }