[PATCH 20.11 3/3] net/mlx5: fix initial link status detection

[Dmitry Kozlyuk]

[ upstream commit 655c3c26c11e7a6f1b5421afe40b06d580b8f2dd ]

Link status change takes time that depends on the HW and the kernel.
It was checked immediately after the change was issued at probing.
If the port had beed down before probing, a "down" state may be read,
while the port would be "up" imminently.
After that, DPDK reported the port as "down" mistakenly
and "ifconfig $DEV up" did not trigger an LSC event,
because from the system's perspective the port was "up" already.

Install Netlink event handler at port probe before requesting the port
to come up in order to receive LSC event even if it comes up
between probe and start.

Fixes: b6499434b83e ("net/mlx5: fix link status initialization")

Signed-off-by: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
---
 drivers/net/mlx5/linux/mlx5_os.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index 0e738d4a59..f98cf90dd8 100644
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -1519,13 +1519,11 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
 	/* Bring Ethernet device up. */
 	DRV_LOG(DEBUG, "port %u forcing Ethernet interface up",
 		eth_dev->data->port_id);
-	mlx5_set_link_up(eth_dev);
-	/*
-	 * Even though the interrupt handler is not installed yet,
-	 * interrupts will still trigger on the async_fd from
-	 * Verbs context returned by ibv_open_device().
-	 */
 	mlx5_link_update(eth_dev, 0);
+	/* Watch LSC interrupts between port probe and port start. */
+	priv->sh->port[priv->dev_port - 1].nl_ih_port_id =
+							eth_dev->data->port_id;
+	mlx5_set_link_up(eth_dev);
 	/* Detect minimal data bytes to inline. */
 	mlx5_set_min_inline(spawn, config);
 	/* Store device configuration on private structure. */
-- 
2.25.1