net/mlx5: fs, add support for no append at software level

Native capability for some steering engines lacks support for adding an
additional match with the same value to the same flow group. To accommodate
the NO APPEND flag in these scenarios, we include the new rule in the
existing flow table entry (fte) without immediate hardware commitment. When
a request is made to delete the corresponding hardware rule, we then commit
the pending rule to hardware.

Only one pending rule is supported because NO_APPEND is primarily used
during replacement operations. In this scenario, a rule is initially added.
When it needs replacement, the new rule is added with NO_APPEND set. Only
after the insertion of the new rule is the original rule deleted.
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20240911201757.1505453-9-saeed@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -1071,7 +1071,7 @@ static int mlx5_cmd_create_match_definer(struct mlx5_flow_root_namespace *ns,
 static u32 mlx5_cmd_get_capabilities(struct mlx5_flow_root_namespace *ns,
 				     enum fs_flow_table_type ft_type)
 {
-	return 0;
+	return MLX5_FLOW_STEERING_CAP_DUPLICATE_MATCH;
 }
 
 static const struct mlx5_flow_cmds mlx5_flow_cmds = {

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

@@ -133,6 +133,7 @@ enum mlx5_flow_steering_capabilty {
 	MLX5_FLOW_STEERING_CAP_VLAN_PUSH_ON_RX = 1UL << 0,
 	MLX5_FLOW_STEERING_CAP_VLAN_POP_ON_TX = 1UL << 1,
 	MLX5_FLOW_STEERING_CAP_MATCH_RANGES = 1UL << 2,
+	MLX5_FLOW_STEERING_CAP_DUPLICATE_MATCH = 1UL << 3,
 };
 
 struct mlx5_flow_steering {
@@ -238,12 +239,18 @@ struct fs_fte_action {
 	struct mlx5_flow_act		action;
 };
 
+struct fs_fte_dup {
+	struct list_head children;
+	struct fs_fte_action act_dests;
+};
+
 /* Type of children is mlx5_flow_rule */
 struct fs_fte {
 	struct fs_node			node;
 	struct mlx5_fs_dr_rule		fs_dr_rule;
 	u32				val[MLX5_ST_SZ_DW_MATCH_PARAM];
 	struct fs_fte_action		act_dests;
+	struct fs_fte_dup		*dup;
 	u32				index;
 	enum fs_fte_status		status;
 	struct rhash_head		hash;

drivers/net/ethernet/mellanox/mlx5/core/steering/fs_dr.c

@@ -813,11 +813,11 @@ static int mlx5_cmd_dr_destroy_ns(struct mlx5_flow_root_namespace *ns)
 static u32 mlx5_cmd_dr_get_capabilities(struct mlx5_flow_root_namespace *ns,
 					enum fs_flow_table_type ft_type)
 {
-	u32 steering_caps = 0;
+	u32 steering_caps = MLX5_FLOW_STEERING_CAP_DUPLICATE_MATCH;
 
 	if (ft_type != FS_FT_FDB ||
 	    MLX5_CAP_GEN(ns->dev, steering_format_version) == MLX5_STEERING_FORMAT_CONNECTX_5)
-		return 0;
+		return steering_caps;
 
 	steering_caps |= MLX5_FLOW_STEERING_CAP_VLAN_PUSH_ON_RX;
 	steering_caps |= MLX5_FLOW_STEERING_CAP_VLAN_POP_ON_TX;