net/mlx5: CT: Allow static allocation of mod headers

As each CT rule uses at least 4 modify header actions, each rule
causes at least 3 reallocations by the mod header actions api.

Allow initial static allocation of the mod acts array, and use it for
CT rules. If the static allocation is exceeded go back to dynamic
allocation.
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en/mod_hdr.c

@@ -176,11 +176,20 @@ mlx5e_mod_hdr_alloc(struct mlx5_core_dev *mdev, int namespace,
 	new_sz = MLX5_MH_ACT_SZ * new_num_actions;
 	old_sz = mod_hdr_acts->max_actions * MLX5_MH_ACT_SZ;
 
-	ret = krealloc(mod_hdr_acts->actions, new_sz, GFP_KERNEL);
+	if (mod_hdr_acts->is_static) {
+		ret = kzalloc(new_sz, GFP_KERNEL);
+		if (ret) {
+			memcpy(ret, mod_hdr_acts->actions, old_sz);
+			mod_hdr_acts->is_static = false;
+		}
+	} else {
+		ret = krealloc(mod_hdr_acts->actions, new_sz, GFP_KERNEL);
+		if (ret)
+			memset(ret + old_sz, 0, new_sz - old_sz);
+	}
 	if (!ret)
 		return ERR_PTR(-ENOMEM);
 
-	memset(ret + old_sz, 0, new_sz - old_sz);
 	mod_hdr_acts->actions = ret;
 	mod_hdr_acts->max_actions = new_num_actions;
 
@@ -191,7 +200,9 @@ mlx5e_mod_hdr_alloc(struct mlx5_core_dev *mdev, int namespace,
 void
 mlx5e_mod_hdr_dealloc(struct mlx5e_tc_mod_hdr_acts *mod_hdr_acts)
 {
-	kfree(mod_hdr_acts->actions);
+	if (!mod_hdr_acts->is_static)
+		kfree(mod_hdr_acts->actions);
+
 	mod_hdr_acts->actions = NULL;
 	mod_hdr_acts->num_actions = 0;
 	mod_hdr_acts->max_actions = 0;

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

@@ -7,14 +7,27 @@
 #include <linux/hashtable.h>
 #include <linux/mlx5/fs.h>
 
+#define MLX5_MH_ACT_SZ MLX5_UN_SZ_BYTES(set_add_copy_action_in_auto)
+
 struct mlx5e_mod_hdr_handle;
 
 struct mlx5e_tc_mod_hdr_acts {
 	int num_actions;
 	int max_actions;
+	bool is_static;
 	void *actions;
 };
 
+#define DECLARE_MOD_HDR_ACTS_ACTIONS(name, len) \
+	u8 name[len][MLX5_MH_ACT_SZ] = {}
+
+#define DECLARE_MOD_HDR_ACTS(name, acts_arr) \
+	struct mlx5e_tc_mod_hdr_acts name = { \
+		.max_actions = ARRAY_SIZE(acts_arr), \
+		.is_static = true, \
+		.actions = acts_arr, \
+	}
+
 char *mlx5e_mod_hdr_alloc(struct mlx5_core_dev *mdev, int namespace,
 			  struct mlx5e_tc_mod_hdr_acts *mod_hdr_acts);
 void mlx5e_mod_hdr_dealloc(struct mlx5e_tc_mod_hdr_acts *mod_hdr_acts);

drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c

@@ -36,6 +36,12 @@
 #define MLX5_CT_LABELS_BITS (mlx5e_tc_attr_to_reg_mappings[LABELS_TO_REG].mlen)
 #define MLX5_CT_LABELS_MASK GENMASK(MLX5_CT_LABELS_BITS - 1, 0)
 
+/* Statically allocate modify actions for
+ * ipv6 and port nat (5) + tuple fields (4) + nic mode zone restore (1) = 10.
+ * This will be increased dynamically if needed (for the ipv6 snat + dnat).
+ */
+#define MLX5_CT_MIN_MOD_ACTS 10
+
 #define ct_dbg(fmt, args...)\
 	netdev_dbg(ct_priv->netdev, "ct_debug: " fmt "\n", ##args)
 
@@ -645,7 +651,8 @@ mlx5_tc_ct_entry_create_mod_hdr(struct mlx5_tc_ct_priv *ct_priv,
 				struct mlx5e_mod_hdr_handle **mh,
 				u8 zone_restore_id, bool nat)
 {
-	struct mlx5e_tc_mod_hdr_acts mod_acts = {};
+	DECLARE_MOD_HDR_ACTS_ACTIONS(actions_arr, MLX5_CT_MIN_MOD_ACTS);
+	DECLARE_MOD_HDR_ACTS(mod_acts, actions_arr);
 	struct flow_action_entry *meta;
 	u16 ct_state = 0;
 	int err;