netdev - [PATCH net 2/2] net/mlx4_en: Avoid unregister

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Date:	Mon, 20 Jun 2016 17:35:09 +0300
From:	Tariq Toukan <tariqt@...lanox.com>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, Eran Ben Elisha <eranbe@...lanox.com>,
	Tariq Toukan <tariqt@...lanox.com>
Subject: [PATCH net 2/2] net/mlx4_en: Avoid unregister_netdev at shutdown flow

From: Eran Ben Elisha <eranbe@...lanox.com>

This allows a clean shutdown, even if some netdev clients do not
release their reference from this netdev. It is enough to release
the HW resources only as the kernel is shutting down.

Fixes: 2ba5fbd62b25 ('net/mlx4_core: Handle AER flow properly')
Signed-off-by: Eran Ben Elisha <eranbe@...lanox.com>
Signed-off-by: Tariq Toukan <tariqt@...lanox.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 17 +++++++++++++++--
 drivers/net/ethernet/mellanox/mlx4/main.c      |  5 ++++-
 include/linux/mlx4/device.h                    |  1 +
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 43f505e..0c0dfd6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2036,11 +2036,20 @@ err:
 	return -ENOMEM;
 }
 
+static void mlx4_en_shutdown(struct net_device *dev)
+{
+	rtnl_lock();
+	netif_device_detach(dev);
+	mlx4_en_close(dev);
+	rtnl_unlock();
+}
 
 void mlx4_en_destroy_netdev(struct net_device *dev)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_dev *mdev = priv->mdev;
+	bool shutdown = mdev->dev->persist->interface_state &
+					    MLX4_INTERFACE_STATE_SHUTDOWN;
 
 	en_dbg(DRV, priv, "Destroying netdev on port:%d\n", priv->port);
 
@@ -2048,7 +2057,10 @@ void mlx4_en_destroy_netdev(struct net_device *dev)
 	if (priv->registered) {
 		devlink_port_type_clear(mlx4_get_devlink_port(mdev->dev,
 							      priv->port));
-		unregister_netdev(dev);
+		if (shutdown)
+			mlx4_en_shutdown(dev);
+		else
+			unregister_netdev(dev);
 	}
 
 	if (priv->allocated)
@@ -2073,7 +2085,8 @@ void mlx4_en_destroy_netdev(struct net_device *dev)
 	kfree(priv->tx_ring);
 	kfree(priv->tx_cq);
 
-	free_netdev(dev);
+	if (!shutdown)
+		free_netdev(dev);
 }
 
 static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu)
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 372ebfa..546fab0 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -4135,8 +4135,11 @@ static void mlx4_shutdown(struct pci_dev *pdev)
 
 	mlx4_info(persist->dev, "mlx4_shutdown was called\n");
 	mutex_lock(&persist->interface_state_mutex);
-	if (persist->interface_state & MLX4_INTERFACE_STATE_UP)
+	if (persist->interface_state & MLX4_INTERFACE_STATE_UP) {
+		/* Notify mlx4 clients that the kernel is being shut down */
+		persist->interface_state |= MLX4_INTERFACE_STATE_SHUTDOWN;
 		mlx4_unload_one(pdev);
+	}
 	mutex_unlock(&persist->interface_state_mutex);
 }
 
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 80dec87..d46a0e7 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -466,6 +466,7 @@ enum {
 enum {
 	MLX4_INTERFACE_STATE_UP		= 1 << 0,
 	MLX4_INTERFACE_STATE_DELETION	= 1 << 1,
+	MLX4_INTERFACE_STATE_SHUTDOWN	= 1 << 2,
 };
 
 #define MSTR_SM_CHANGE_MASK (MLX4_EQ_PORT_INFO_MSTR_SM_SL_CHANGE_MASK | \
-- 
1.8.3.1