net/mlx5e: Support ethtool tcp-data-split settings

In mlx5, tcp header-data split requires HW GRO to be on.

Enabling it fails when HW GRO is off.
mlx5e_fix_features now keeps HW GRO on when tcp data split is enabled.
Finally, when tcp data split is disabled, features are updated to maybe
remove the forced HW GRO.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250616141441.1243044-12-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -32,6 +32,7 @@
 
 #include <linux/dim.h>
 #include <linux/ethtool_netlink.h>
+#include <net/netdev_queues.h>
 
 #include "en.h"
 #include "en/channels.h"
@@ -365,11 +366,6 @@ void mlx5e_ethtool_get_ringparam(struct mlx5e_priv *priv,
 	param->tx_max_pending = 1 << MLX5E_PARAMS_MAXIMUM_LOG_SQ_SIZE;
 	param->rx_pending     = 1 << priv->channels.params.log_rq_mtu_frames;
 	param->tx_pending     = 1 << priv->channels.params.log_sq_size;
-
-	kernel_param->tcp_data_split =
-		(priv->channels.params.packet_merge.type == MLX5E_PACKET_MERGE_SHAMPO) ?
-		ETHTOOL_TCP_DATA_SPLIT_ENABLED :
-		ETHTOOL_TCP_DATA_SPLIT_DISABLED;
 }
 
 static void mlx5e_get_ringparam(struct net_device *dev,
@@ -382,6 +378,27 @@ static void mlx5e_get_ringparam(struct net_device *dev,
 	mlx5e_ethtool_get_ringparam(priv, param, kernel_param);
 }
 
+static bool mlx5e_ethtool_set_tcp_data_split(struct mlx5e_priv *priv,
+					     u8 tcp_data_split,
+					     struct netlink_ext_ack *extack)
+{
+	struct net_device *dev = priv->netdev;
+
+	if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    !(dev->features & NETIF_F_GRO_HW)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "TCP-data-split is not supported when GRO HW is disabled");
+		return false;
+	}
+
+	/* Might need to disable HW-GRO if it was kept on due to hds. */
+	if (tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_DISABLED &&
+	    dev->cfg->hds_config == ETHTOOL_TCP_DATA_SPLIT_ENABLED)
+		netdev_update_features(priv->netdev);
+
+	return true;
+}
+
 int mlx5e_ethtool_set_ringparam(struct mlx5e_priv *priv,
 				struct ethtool_ringparam *param,
 				struct netlink_ext_ack *extack)
@@ -440,6 +457,11 @@ static int mlx5e_set_ringparam(struct net_device *dev,
 {
 	struct mlx5e_priv *priv = netdev_priv(dev);
 
+	if (!mlx5e_ethtool_set_tcp_data_split(priv,
+					      kernel_param->tcp_data_split,
+					      extack))
+		return -EINVAL;
+
 	return mlx5e_ethtool_set_ringparam(priv, param, extack);
 }
 
@@ -2623,6 +2645,7 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
 				     ETHTOOL_COALESCE_USE_ADAPTIVE |
 				     ETHTOOL_COALESCE_USE_CQE,
 	.supported_input_xfrm = RXH_XFRM_SYM_OR_XOR,
+	.supported_ring_params = ETHTOOL_RING_USE_TCP_DATA_SPLIT,
 	.get_drvinfo       = mlx5e_get_drvinfo,
 	.get_link          = ethtool_op_get_link,
 	.get_link_ext_state  = mlx5e_get_link_ext_state,

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

@@ -4413,6 +4413,7 @@ static netdev_features_t mlx5e_fix_uplink_rep_features(struct net_device *netdev
 static netdev_features_t mlx5e_fix_features(struct net_device *netdev,
 					    netdev_features_t features)
 {
+	struct netdev_config *cfg = netdev->cfg_pending;
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 	struct mlx5e_vlan_table *vlan;
 	struct mlx5e_params *params;
@@ -4479,6 +4480,13 @@ static netdev_features_t mlx5e_fix_features(struct net_device *netdev,
 		}
 	}
 
+	/* The header-data split ring param requires HW GRO to stay enabled. */
+	if (cfg && cfg->hds_config == ETHTOOL_TCP_DATA_SPLIT_ENABLED &&
+	    !(features & NETIF_F_GRO_HW)) {
+		netdev_warn(netdev, "Keeping HW-GRO enabled, TCP header-data split depends on it\n");
+		features |= NETIF_F_GRO_HW;
+	}
+
 	if (mlx5e_is_uplink_rep(priv)) {
 		features = mlx5e_fix_uplink_rep_features(netdev, features);
 		netdev->netns_immutable = true;