[PATCH net-next] net/mlx5e: Report link down on administrative close

[Manjunath Patil <manjunath.b.patil@oracle.com>]

mlx5e_update_carrier() reports both link-up and link-down carrier
changes, but an administrative down does not reach it in practice. The
close path first changes the port admin state and then clears
MLX5E_STATE_OPENED and drops carrier silently in mlx5e_close_locked().
Any queued carrier worker will skip update_carrier() once the device is
no longer opened.

This leaves "ip link set dev <dev> down" without a matching netdev
"Link down" message, while reopening the device still reports "Link up".

Report the link-down transition in mlx5e_close() before the common close
helper clears the opened state and drops carrier. Guard the message with
the current opened and carrier state to avoid duplicates when the netdev
is already closed or carrier is already down.

Assisted-by: Codex:gpt-5
Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com>
---
Validation:
- Built an OL8 mainline test kernel from this change.
- Booted 7.1.0-rc6.bug123456.el8.v1.x86_64 on an mlx5-backed VM.
- Confirmed `ip link set dev re0 down/up` and `re1 down/up` now emit
  netdev `Link down` and `Link up` messages, alongside the existing RDMA
  port state notifications.

 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 8f2b3abe0092..a04a89f0eddf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -3628,6 +3628,9 @@ int mlx5e_close(struct net_device *netdev)
 
 	mutex_lock(&priv->state_lock);
 	mlx5e_modify_admin_state(priv->mdev, MLX5_PORT_DOWN);
+	if (test_bit(MLX5E_STATE_OPENED, &priv->state) &&
+	    netif_carrier_ok(netdev))
+		netdev_info(netdev, "Link down\n");
 	err = mlx5e_close_locked(netdev);
 	mutex_unlock(&priv->state_lock);
 

base-commit: e43ffb69e0438cddd72aaa30898b4dc446f664f8
-- 
2.47.3