net/mlx5e: Change flow flags type to unsigned long

To remove dependency on rtnl lock and allow concurrent modification of
'flags' field of tc flow structure, change flow flag type to unsigned long
and use atomic bit ops for reading and changing the flags. Implement
auxiliary functions for setting, resetting and getting specific flag, and
for checking most often used flag values.

Always set flags with smp_mb__before_atomic() to ensure that all
mlx5e_tc_flow are updated before concurrent readers can read new flags
value. Rearrange all code paths to actually set flow->rule[] pointers
before setting the OFFLOADED flag. On read side, use smp_mb__after_atomic()
when accessing flags to ensure that offload-related flow fields are only
read after the flags.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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

@@ -3429,7 +3429,7 @@ static int mlx5e_setup_tc_mqprio(struct mlx5e_priv *priv,
 #ifdef CONFIG_MLX5_ESWITCH
 static int mlx5e_setup_tc_cls_flower(struct mlx5e_priv *priv,
 				     struct flow_cls_offload *cls_flower,
-				     int flags)
+				     unsigned long flags)
 {
 	switch (cls_flower->command) {
 	case FLOW_CLS_REPLACE:
@@ -3449,12 +3449,12 @@ static int mlx5e_setup_tc_cls_flower(struct mlx5e_priv *priv,
 static int mlx5e_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
 				   void *cb_priv)
 {
+	unsigned long flags = MLX5_TC_FLAG(INGRESS) | MLX5_TC_FLAG(NIC_OFFLOAD);
 	struct mlx5e_priv *priv = cb_priv;
 
 	switch (type) {
 	case TC_SETUP_CLSFLOWER:
-		return mlx5e_setup_tc_cls_flower(priv, type_data, MLX5E_TC_INGRESS |
-						 MLX5E_TC_NIC_OFFLOAD);
+		return mlx5e_setup_tc_cls_flower(priv, type_data, flags);
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -3647,7 +3647,7 @@ static int set_feature_tc_num_filters(struct net_device *netdev, bool enable)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 
-	if (!enable && mlx5e_tc_num_filters(priv, MLX5E_TC_NIC_OFFLOAD)) {
+	if (!enable && mlx5e_tc_num_filters(priv, MLX5_TC_FLAG(NIC_OFFLOAD))) {
 		netdev_err(netdev,
 			   "Active offloaded tc filters, can't turn hw_tc_offload off\n");
 		return -EINVAL;

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

@@ -659,8 +659,8 @@ mlx5e_rep_indr_offload(struct net_device *netdev,
 		       struct flow_cls_offload *flower,
 		       struct mlx5e_rep_indr_block_priv *indr_priv)
 {
+	unsigned long flags = MLX5_TC_FLAG(EGRESS) | MLX5_TC_FLAG(ESW_OFFLOAD);
 	struct mlx5e_priv *priv = netdev_priv(indr_priv->rpriv->netdev);
-	int flags = MLX5E_TC_EGRESS | MLX5E_TC_ESW_OFFLOAD;
 	int err = 0;
 
 	switch (flower->command) {
@@ -1159,12 +1159,12 @@ mlx5e_rep_setup_tc_cls_flower(struct mlx5e_priv *priv,
 static int mlx5e_rep_setup_tc_cb(enum tc_setup_type type, void *type_data,
 				 void *cb_priv)
 {
+	unsigned long flags = MLX5_TC_FLAG(INGRESS) | MLX5_TC_FLAG(ESW_OFFLOAD);
 	struct mlx5e_priv *priv = cb_priv;
 
 	switch (type) {
 	case TC_SETUP_CLSFLOWER:
-		return mlx5e_rep_setup_tc_cls_flower(priv, type_data, MLX5E_TC_INGRESS |
-						     MLX5E_TC_ESW_OFFLOAD);
+		return mlx5e_rep_setup_tc_cls_flower(priv, type_data, flags);
 	default:
 		return -EOPNOTSUPP;
 	}

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

@@ -40,13 +40,15 @@
 #ifdef CONFIG_MLX5_ESWITCH
 
 enum {
-	MLX5E_TC_INGRESS = BIT(0),
-	MLX5E_TC_EGRESS  = BIT(1),
-	MLX5E_TC_NIC_OFFLOAD = BIT(2),
-	MLX5E_TC_ESW_OFFLOAD = BIT(3),
-	MLX5E_TC_LAST_EXPORTED_BIT = 3,
+	MLX5E_TC_FLAG_INGRESS_BIT,
+	MLX5E_TC_FLAG_EGRESS_BIT,
+	MLX5E_TC_FLAG_NIC_OFFLOAD_BIT,
+	MLX5E_TC_FLAG_ESW_OFFLOAD_BIT,
+	MLX5E_TC_FLAG_LAST_EXPORTED_BIT = MLX5E_TC_FLAG_ESW_OFFLOAD_BIT,
 };
 
+#define MLX5_TC_FLAG(flag) BIT(MLX5E_TC_FLAG_##flag##_BIT)
+
 int mlx5e_tc_nic_init(struct mlx5e_priv *priv);
 void mlx5e_tc_nic_cleanup(struct mlx5e_priv *priv);
 
@@ -54,12 +56,12 @@ int mlx5e_tc_esw_init(struct rhashtable *tc_ht);
 void mlx5e_tc_esw_cleanup(struct rhashtable *tc_ht);
 
 int mlx5e_configure_flower(struct net_device *dev, struct mlx5e_priv *priv,
-			   struct flow_cls_offload *f, int flags);
+			   struct flow_cls_offload *f, unsigned long flags);
 int mlx5e_delete_flower(struct net_device *dev, struct mlx5e_priv *priv,
-			struct flow_cls_offload *f, int flags);
+			struct flow_cls_offload *f, unsigned long flags);
 
 int mlx5e_stats_flower(struct net_device *dev, struct mlx5e_priv *priv,
-		       struct flow_cls_offload *f, int flags);
+		       struct flow_cls_offload *f, unsigned long flags);
 
 struct mlx5e_encap_entry;
 void mlx5e_tc_encap_flows_add(struct mlx5e_priv *priv,
@@ -70,7 +72,7 @@ void mlx5e_tc_encap_flows_del(struct mlx5e_priv *priv,
 struct mlx5e_neigh_hash_entry;
 void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe);
 
-int mlx5e_tc_num_filters(struct mlx5e_priv *priv, int flags);
+int mlx5e_tc_num_filters(struct mlx5e_priv *priv, unsigned long flags);
 
 void mlx5e_tc_reoffload_flows_work(struct work_struct *work);
 
@@ -80,7 +82,11 @@ bool mlx5e_is_valid_eswitch_fwd_dev(struct mlx5e_priv *priv,
 #else /* CONFIG_MLX5_ESWITCH */
 static inline int  mlx5e_tc_nic_init(struct mlx5e_priv *priv) { return 0; }
 static inline void mlx5e_tc_nic_cleanup(struct mlx5e_priv *priv) {}
-static inline int  mlx5e_tc_num_filters(struct mlx5e_priv *priv, int flags) { return 0; }
+static inline int  mlx5e_tc_num_filters(struct mlx5e_priv *priv,
+					unsigned long flags)
+{
+	return 0;
+}
 #endif
 
 #endif /* __MLX5_EN_TC_H__ */