net/mlx5: Use one completion vector if eth is disabled

If eth is disabled by devlink, use only a single completion vector to
have minimum performance of all users of completion vectors. This also
affects Infiniband performance.

The rest of the vectors can be used by other consumers on a first come
first served basis.

mlx5_vdpa will make use of this to allocate dedicated vectors for its
own use.
Signed-off-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

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

@@ -35,6 +35,7 @@
 #include <linux/mlx5/mlx5_ifc_vdpa.h>
 #include <linux/mlx5/vport.h>
 #include "mlx5_core.h"
+#include "devlink.h"
 
 /* intf dev list mutex */
 static DEFINE_MUTEX(mlx5_intf_mutex);
@@ -109,17 +110,6 @@ bool mlx5_eth_supported(struct mlx5_core_dev *dev)
 	return true;
 }
 
-static bool is_eth_enabled(struct mlx5_core_dev *dev)
-{
-	union devlink_param_value val;
-	int err;
-
-	err = devl_param_driverinit_value_get(priv_to_devlink(dev),
-					      DEVLINK_PARAM_GENERIC_ID_ENABLE_ETH,
-					      &val);
-	return err ? false : val.vbool;
-}
-
 bool mlx5_vnet_supported(struct mlx5_core_dev *dev)
 {
 	if (!IS_ENABLED(CONFIG_MLX5_VDPA_NET))
@@ -251,7 +241,7 @@ static const struct mlx5_adev_device {
 					 .is_enabled = &is_ib_enabled },
 	[MLX5_INTERFACE_PROTOCOL_ETH] = { .suffix = "eth",
 					  .is_supported = &mlx5_eth_supported,
-					  .is_enabled = &is_eth_enabled },
+					  .is_enabled = &mlx5_core_is_eth_enabled },
 	[MLX5_INTERFACE_PROTOCOL_ETH_REP] = { .suffix = "eth-rep",
 					   .is_supported = &is_eth_rep_supported },
 	[MLX5_INTERFACE_PROTOCOL_IB_REP] = { .suffix = "rdma-rep",

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

@@ -44,4 +44,15 @@ void mlx5_devlink_free(struct devlink *devlink);
 int mlx5_devlink_params_register(struct devlink *devlink);
 void mlx5_devlink_params_unregister(struct devlink *devlink);
 
+static inline bool mlx5_core_is_eth_enabled(struct mlx5_core_dev *dev)
+{
+	union devlink_param_value val;
+	int err;
+
+	err = devl_param_driverinit_value_get(priv_to_devlink(dev),
+					      DEVLINK_PARAM_GENERIC_ID_ENABLE_ETH,
+					      &val);
+	return err ? false : val.vbool;
+}
+
 #endif /* __MLX5_DEVLINK_H__ */

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

@@ -1120,6 +1120,13 @@ static int get_num_eqs(struct mlx5_core_dev *dev)
 	int max_eqs_sf;
 	int num_eqs;
 
+	/* If ethernet is disabled we use just a single completion vector to
+	 * have the other vectors available for other drivers using mlx5_core. For
+	 * example, mlx5_vdpa
+	 */
+	if (!mlx5_core_is_eth_enabled(dev) && mlx5_eth_supported(dev))
+		return 1;
+
 	max_dev_eqs = MLX5_CAP_GEN(dev, max_num_eqs) ?
 		      MLX5_CAP_GEN(dev, max_num_eqs) :
 		      1 << MLX5_CAP_GEN(dev, log_max_eq);