net/mlx5: Cache the system image guid

The system image guid is a read-only field which is used by the TC
offloads code to determine if two mlx5 devices belong to the same
ASIC while adding flows.

Read this once and save it on the core device rather than querying each
time an offloaded flow is added.
Signed-off-by: Alaa Hleihel <alaa@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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

@@ -2040,8 +2040,8 @@ static bool same_hw_devs(struct mlx5e_priv *priv, struct mlx5e_priv *peer_priv)
 	fmdev = priv->mdev;
 	pmdev = peer_priv->mdev;
 
-	mlx5_query_nic_vport_system_image_guid(fmdev, &fsystem_guid);
-	mlx5_query_nic_vport_system_image_guid(pmdev, &psystem_guid);
+	fsystem_guid = mlx5_query_nic_system_image_guid(fmdev);
+	psystem_guid = mlx5_query_nic_system_image_guid(pmdev);
 
 	return (fsystem_guid == psystem_guid);
 }

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

@@ -1201,3 +1201,12 @@ int mlx5_nic_vport_unaffiliate_multiport(struct mlx5_core_dev *port_mdev)
 	return err;
 }
 EXPORT_SYMBOL_GPL(mlx5_nic_vport_unaffiliate_multiport);
+
+u64 mlx5_query_nic_system_image_guid(struct mlx5_core_dev *mdev)
+{
+	if (!mdev->sys_image_guid)
+		mlx5_query_nic_vport_system_image_guid(mdev, &mdev->sys_image_guid);
+
+	return mdev->sys_image_guid;
+}
+EXPORT_SYMBOL_GPL(mlx5_query_nic_system_image_guid);

include/linux/mlx5/driver.h

@@ -838,6 +838,7 @@ struct mlx5_core_dev {
 		u32 fpga[MLX5_ST_SZ_DW(fpga_cap)];
 		u32 qcam[MLX5_ST_SZ_DW(qcam_reg)];
 	} caps;
+	u64			sys_image_guid;
 	phys_addr_t		iseg_base;
 	struct mlx5_init_seg __iomem *iseg;
 	enum mlx5_device_state	state;

include/linux/mlx5/vport.h

@@ -121,4 +121,6 @@ int mlx5_nic_vport_query_local_lb(struct mlx5_core_dev *mdev, bool *status);
 int mlx5_nic_vport_affiliate_multiport(struct mlx5_core_dev *master_mdev,
 				       struct mlx5_core_dev *port_mdev);
 int mlx5_nic_vport_unaffiliate_multiport(struct mlx5_core_dev *port_mdev);
+
+u64 mlx5_query_nic_system_image_guid(struct mlx5_core_dev *mdev);
 #endif /* __MLX5_VPORT_H__ */