[dpdk-stable] [PATCH] net/mlx5: fix switchdev mode recognition

[Viacheslav Ovsiienko]

The new kernels might add the switch_id attribute to the
Netlink replies and this caused the wrong recognition
of the E-Switch presence. The single uplink device was
erroneously recognized as master and it caused the
extending match for source vport index on all installed
flows, including the default ones, and adding extra hops
in the steering engine, that affected the maximal
throughput packet rate.

The extra check for the new device name format (it supposes
the new kernel) and the device is only one is added. If this
check succeeds the E-Switch presence is considered as wrongly
detected and overridden.

Fixes: 30a86157f6d5 ("net/mlx5: support PF representor")
Cc: stable at dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx5/linux/mlx5_os.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index 54e4a1fe60..92b3009786 100644
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -2290,6 +2290,18 @@ mlx5_os_pci_probe_pf(struct rte_pci_device *pci_dev,
 			ret = -rte_errno;
 			goto exit;
 		}
+		/*
+		 * New kernels may add the switch_id attribute for the case
+		 * there is no E-Switch and we wrongly recognized the
+		 * only device as master. Override this if there is the
+		 * single device with single port and new device name
+		 * format present.
+		 */
+		if (nd == 1 &&
+		    list[0].info.name_type == MLX5_PHYS_PORT_NAME_TYPE_UPLINK) {
+			list[0].info.master = 0;
+			list[0].info.representor = 0;
+		}
 	}
 	MLX5_ASSERT(ns);
 	/*
-- 
2.18.1