Revert "RDMA/mlx5: Fix devlink deadlock on net namespace deletion"

commit de641d7 upstream.

This reverts commit fbdd004.

Due to commit in fixes tag, netdevice events were received only in one net
namespace of mlx5_core_dev. Due to this when netdevice events arrive in
net namespace other than net namespace of mlx5_core_dev, they are missed.

This results in empty GID table due to RDMA device being detached from its
net device.

Hence, revert back to receive netdevice events in all net namespaces to
restore back RDMA functionality in non init_net net namespace. The
deadlock will have to be addressed in another patch.

Fixes: fbdd004 ("RDMA/mlx5: Fix devlink deadlock on net namespace deletion")
Link: https://lore.kernel.org/r/20210117092633.10690-1-leon@kernel.org
Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/infiniband/hw/mlx5/main.c

@@ -3305,8 +3305,7 @@ static int mlx5_add_netdev_notifier(struct mlx5_ib_dev *dev, u8 port_num)
 	int err;
 
 	dev->port[port_num].roce.nb.notifier_call = mlx5_netdev_event;
-	err = register_netdevice_notifier_net(mlx5_core_net(dev->mdev),
-					      &dev->port[port_num].roce.nb);
+	err = register_netdevice_notifier(&dev->port[port_num].roce.nb);
 	if (err) {
 		dev->port[port_num].roce.nb.notifier_call = NULL;
 		return err;
@@ -3318,8 +3317,7 @@ static int mlx5_add_netdev_notifier(struct mlx5_ib_dev *dev, u8 port_num)
 static void mlx5_remove_netdev_notifier(struct mlx5_ib_dev *dev, u8 port_num)
 {
 	if (dev->port[port_num].roce.nb.notifier_call) {
-		unregister_netdevice_notifier_net(mlx5_core_net(dev->mdev),
-						  &dev->port[port_num].roce.nb);
+		unregister_netdevice_notifier(&dev->port[port_num].roce.nb);
 		dev->port[port_num].roce.nb.notifier_call = NULL;
 	}
 }

drivers/net/ethernet/mellanox/mlx5/core/lib/mlx5.h

@@ -90,4 +90,9 @@ int mlx5_create_encryption_key(struct mlx5_core_dev *mdev,
 			       u32 key_type, u32 *p_key_id);
 void mlx5_destroy_encryption_key(struct mlx5_core_dev *mdev, u32 key_id);
 
+static inline struct net *mlx5_core_net(struct mlx5_core_dev *dev)
+{
+	return devlink_net(priv_to_devlink(dev));
+}
+
 #endif

include/linux/mlx5/driver.h

@@ -1213,22 +1213,4 @@ static inline bool mlx5_is_roce_enabled(struct mlx5_core_dev *dev)
 	return val.vbool;
 }
 
-/**
- * mlx5_core_net - Provide net namespace of the mlx5_core_dev
- * @dev: mlx5 core device
- *
- * mlx5_core_net() returns the net namespace of mlx5 core device.
- * This can be called only in below described limited context.
- * (a) When a devlink instance for mlx5_core is registered and
- *     when devlink reload operation is disabled.
- *     or
- * (b) during devlink reload reload_down() and reload_up callbacks
- *     where it is ensured that devlink instance's net namespace is
- *     stable.
- */
-static inline struct net *mlx5_core_net(struct mlx5_core_dev *dev)
-{
-	return devlink_net(priv_to_devlink(dev));
-}
-
 #endif /* MLX5_DRIVER_H */