net/mlx5e: Improve ethtool rxnfc callback structure

Don't choose who implements the rxnfc "get/set" callbacks according to
CONFIG_MLX5_EN_RXNFC, instead have the callbacks always available and
delegate to a function of a different driver module when needed
(en_fs_ethtool.c), have stubs in en/fs.h to fallback to when
en_fs_ethtool.c is compiled out, to avoid complications and ifdefs in
en_main.c.
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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

@@ -132,12 +132,17 @@ struct mlx5e_ethtool_steering {
 
 void mlx5e_ethtool_init_steering(struct mlx5e_priv *priv);
 void mlx5e_ethtool_cleanup_steering(struct mlx5e_priv *priv);
-int mlx5e_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd);
-int mlx5e_get_rxnfc(struct net_device *dev,
+int mlx5e_ethtool_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd);
+int mlx5e_ethtool_get_rxnfc(struct net_device *dev,
 			    struct ethtool_rxnfc *info, u32 *rule_locs);
 #else
 static inline void mlx5e_ethtool_init_steering(struct mlx5e_priv *priv)    { }
 static inline void mlx5e_ethtool_cleanup_steering(struct mlx5e_priv *priv) { }
+static inline int mlx5e_ethtool_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
+{ return -EOPNOTSUPP; }
+static inline int mlx5e_ethtool_get_rxnfc(struct net_device *dev,
+					  struct ethtool_rxnfc *info, u32 *rule_locs)
+{ return -EOPNOTSUPP; }
 #endif /* CONFIG_MLX5_EN_RXNFC */
 
 #ifdef CONFIG_MLX5_EN_ARFS

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

@@ -1888,21 +1888,27 @@ static u32 mlx5e_get_priv_flags(struct net_device *netdev)
 	return priv->channels.params.pflags;
 }
 
-#ifndef CONFIG_MLX5_EN_RXNFC
-/* When CONFIG_MLX5_EN_RXNFC=n we only support ETHTOOL_GRXRINGS
- * otherwise this function will be defined from en_fs_ethtool.c
- */
 static int mlx5e_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info, u32 *rule_locs)
 {
 	struct mlx5e_priv *priv = netdev_priv(dev);
 
-	if (info->cmd != ETHTOOL_GRXRINGS)
-		return -EOPNOTSUPP;
-	/* ring_count is needed by ethtool -x */
+	/* ETHTOOL_GRXRINGS is needed by ethtool -x which is not part
+	 * of rxnfc. We keep this logic out of mlx5e_ethtool_get_rxnfc,
+	 * to avoid breaking "ethtool -x" when mlx5e_ethtool_get_rxnfc
+	 * is compiled out via CONFIG_MLX5_EN_RXNFC=n.
+	 */
+	if (info->cmd == ETHTOOL_GRXRINGS) {
 		info->data = priv->channels.params.num_channels;
 		return 0;
+	}
+
+	return mlx5e_ethtool_get_rxnfc(dev, info, rule_locs);
+}
+
+static int mlx5e_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
+{
+	return mlx5e_ethtool_set_rxnfc(dev, cmd);
 }
-#endif
 
 const struct ethtool_ops mlx5e_ethtool_ops = {
 	.get_drvinfo       = mlx5e_get_drvinfo,
@@ -1923,9 +1929,7 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
 	.get_rxfh          = mlx5e_get_rxfh,
 	.set_rxfh          = mlx5e_set_rxfh,
 	.get_rxnfc         = mlx5e_get_rxnfc,
-#ifdef CONFIG_MLX5_EN_RXNFC
 	.set_rxnfc         = mlx5e_set_rxnfc,
-#endif
 	.get_tunable       = mlx5e_get_tunable,
 	.set_tunable       = mlx5e_set_tunable,
 	.get_pauseparam    = mlx5e_get_pauseparam,

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

@@ -887,10 +887,10 @@ static int mlx5e_get_rss_hash_opt(struct mlx5e_priv *priv,
 	return 0;
 }
 
-int mlx5e_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
+int mlx5e_ethtool_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
 {
-	int err = 0;
 	struct mlx5e_priv *priv = netdev_priv(dev);
+	int err = 0;
 
 	switch (cmd->cmd) {
 	case ETHTOOL_SRXCLSRLINS:
@@ -910,16 +910,13 @@ int mlx5e_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
 	return err;
 }
 
-int mlx5e_get_rxnfc(struct net_device *dev,
+int mlx5e_ethtool_get_rxnfc(struct net_device *dev,
 			    struct ethtool_rxnfc *info, u32 *rule_locs)
 {
 	struct mlx5e_priv *priv = netdev_priv(dev);
 	int err = 0;
 
 	switch (info->cmd) {
-	case ETHTOOL_GRXRINGS:
-		info->data = priv->channels.params.num_channels;
-		break;
 	case ETHTOOL_GRXCLSRLCNT:
 		info->rule_cnt = priv->fs.ethtool.tot_num_rules;
 		break;