net/mlx5e: TC, Hold sample_attr on stack instead of pointer

In later commit we are going to instantiate multiple attr instances
for flow instead of single attr.
Parsing TC sample allocates a new memory but there is no symmetric
cleanup in the infrastructure.
To avoid asymmetric alloc/free use sample_attr as part of the flow attr
and not allocated and held as a pointer.
This will avoid a cleanup leak when sample action is not on the first
attr.
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/sample.c

@@ -28,11 +28,7 @@ tc_act_parse_sample(struct mlx5e_tc_act_parse_state *parse_state,
 		    struct mlx5e_priv *priv,
 		    struct mlx5_flow_attr *attr)
 {
-	struct mlx5e_sample_attr *sample_attr;
-
-	sample_attr = kzalloc(sizeof(*attr->sample_attr), GFP_KERNEL);
-	if (!sample_attr)
-		return -ENOMEM;
+	struct mlx5e_sample_attr *sample_attr = &attr->sample_attr;
 
 	sample_attr->rate = act->sample.rate;
 	sample_attr->group_num = act->sample.psample_group->group_num;
@@ -40,7 +36,6 @@ tc_act_parse_sample(struct mlx5e_tc_act_parse_state *parse_state,
 	if (act->sample.truncate)
 		sample_attr->trunc_size = act->sample.trunc_size;
 
-	attr->sample_attr = sample_attr;
 	flow_flag_set(parse_state->flow, SAMPLE);
 
 	return 0;

drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c

@@ -513,7 +513,7 @@ mlx5e_tc_sample_offload(struct mlx5e_tc_psample *tc_psample,
 	sample_flow = kzalloc(sizeof(*sample_flow), GFP_KERNEL);
 	if (!sample_flow)
 		return ERR_PTR(-ENOMEM);
-	sample_attr = attr->sample_attr;
+	sample_attr = &attr->sample_attr;
 	sample_attr->sample_flow = sample_flow;
 
 	/* For NICs with reg_c_preserve support or decap action, use
@@ -546,6 +546,7 @@ mlx5e_tc_sample_offload(struct mlx5e_tc_psample *tc_psample,
 		err = PTR_ERR(sample_flow->sampler);
 		goto err_sampler;
 	}
+	sample_attr->sampler_id = sample_flow->sampler->sampler_id;
 
 	/* Create an id mapping reg_c0 value to sample object. */
 	restore_obj.type = MLX5_MAPPED_OBJ_SAMPLE;
@@ -585,8 +586,7 @@ mlx5e_tc_sample_offload(struct mlx5e_tc_psample *tc_psample,
 	pre_attr->outer_match_level = attr->outer_match_level;
 	pre_attr->chain = attr->chain;
 	pre_attr->prio = attr->prio;
-	pre_attr->sample_attr = attr->sample_attr;
-	sample_attr->sampler_id = sample_flow->sampler->sampler_id;
+	pre_attr->sample_attr = *sample_attr;
 	pre_esw_attr = pre_attr->esw_attr;
 	pre_esw_attr->in_mdev = esw_attr->in_mdev;
 	pre_esw_attr->in_rep = esw_attr->in_rep;
@@ -633,11 +633,11 @@ mlx5e_tc_sample_unoffload(struct mlx5e_tc_psample *tc_psample,
 	 * will hit fw syndromes.
 	 */
 	esw = tc_psample->esw;
-	sample_flow = attr->sample_attr->sample_flow;
+	sample_flow = attr->sample_attr.sample_flow;
 	mlx5_eswitch_del_offloaded_rule(esw, sample_flow->pre_rule, sample_flow->pre_attr);
 
 	sample_restore_put(tc_psample, sample_flow->restore);
-	mapping_remove(esw->offloads.reg_c0_obj_pool, attr->sample_attr->restore_obj_id);
+	mapping_remove(esw->offloads.reg_c0_obj_pool, attr->sample_attr.restore_obj_id);
 	sampler_put(tc_psample, sample_flow->sampler);
 	if (sample_flow->post_act_handle)
 		mlx5e_tc_post_act_del(tc_psample->post_act, sample_flow->post_act_handle);

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -1682,7 +1682,6 @@ static void mlx5e_tc_del_fdb_flow(struct mlx5e_priv *priv,
 	if (flow_flag_test(flow, L3_TO_L2_DECAP))
 		mlx5e_detach_decap(priv, flow);
 
-	kfree(attr->sample_attr);
 	kvfree(attr->esw_attr->rx_tun_attr);
 	kvfree(attr->parse_attr);
 	kfree(flow->attr);

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

@@ -71,7 +71,7 @@ struct mlx5_flow_attr {
 	struct mlx5_fc *counter;
 	struct mlx5_modify_hdr *modify_hdr;
 	struct mlx5_ct_attr ct_attr;
-	struct mlx5e_sample_attr *sample_attr;
+	struct mlx5e_sample_attr sample_attr;
 	struct mlx5e_tc_flow_parse_attr *parse_attr;
 	u32 chain;
 	u16 prio;

drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c

@@ -201,12 +201,12 @@ esw_cleanup_decap_indir(struct mlx5_eswitch *esw,
 static int
 esw_setup_sampler_dest(struct mlx5_flow_destination *dest,
 		       struct mlx5_flow_act *flow_act,
-		       struct mlx5_flow_attr *attr,
+		       u32 sampler_id,
 		       int i)
 {
 	flow_act->flags |= FLOW_ACT_IGNORE_FLOW_LEVEL;
 	dest[i].type = MLX5_FLOW_DESTINATION_TYPE_FLOW_SAMPLER;
-	dest[i].sampler_id = attr->sample_attr->sampler_id;
+	dest[i].sampler_id = sampler_id;
 
 	return 0;
 }
@@ -466,7 +466,7 @@ esw_setup_dests(struct mlx5_flow_destination *dest,
 		attr->flags |= MLX5_ESW_ATTR_FLAG_SRC_REWRITE;
 
 	if (attr->flags & MLX5_ESW_ATTR_FLAG_SAMPLE) {
-		esw_setup_sampler_dest(dest, flow_act, attr, *i);
+		esw_setup_sampler_dest(dest, flow_act, attr->sample_attr.sampler_id, *i);
 		(*i)++;
 	} else if (attr->dest_ft) {
 		esw_setup_ft_dest(dest, flow_act, esw, attr, spec, *i);