net/mlx5e: Add accelerated RFS support

Implement ndo_rx_flow_steer ndo.
A new flow steering rule will be composed from the
skb 4-tuple and added to the hardware aRFS flow table.

Each rule is stored in an internal hash table, if such
skb 4-tuple rule already exists we update the corresponding
hardware steering rule with the new destination.

For garbage collection rps_may_expire_flow will be
invoked for a limited amount of old rules upon any
ndo_rx_flow_steer invocation.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Maor Gottlieb

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

@@ -448,9 +448,12 @@ struct mlx5e_ttc_table {
 	struct mlx5_flow_rule	 *rules[MLX5E_NUM_TT];
 };
 
+#define ARFS_HASH_SHIFT BITS_PER_BYTE
+#define ARFS_HASH_SIZE BIT(BITS_PER_BYTE)
 struct arfs_table {
 	struct mlx5e_flow_table  ft;
 	struct mlx5_flow_rule    *default_rule;
+	struct hlist_head	 rules_hash[ARFS_HASH_SIZE];
 };
 
 enum  arfs_type {
@@ -463,6 +466,11 @@ enum  arfs_type {
 
 struct mlx5e_arfs_tables {
 	struct arfs_table arfs_tables[ARFS_NUM_TYPES];
+	/* Protect aRFS rules list */
+	spinlock_t                     arfs_lock;
+	struct list_head               rules;
+	int                            last_filter_id;
+	struct workqueue_struct        *wq;
 };
 
 /* NIC prio FTS */
@@ -685,6 +693,8 @@ static inline void mlx5e_arfs_destroy_tables(struct mlx5e_priv *priv) {}
 #else
 int mlx5e_arfs_create_tables(struct mlx5e_priv *priv);
 void mlx5e_arfs_destroy_tables(struct mlx5e_priv *priv);
+int mlx5e_rx_flow_steer(struct net_device *dev, const struct sk_buff *skb,
+			u16 rxq_index, u32 flow_id);
 #endif
 
 u16 mlx5e_get_max_inline_cap(struct mlx5_core_dev *mdev);