RDMA/mlx5: Track netdev to avoid deadlock during netdev notifier unregister

When removing a network namespace with mlx5 devlink instance being in
it, following callchain is performed:

cleanup_net (takes down_read(&pernet_ops_rwsem)
devlink_pernet_pre_exit()
devlink_reload()
mlx5_devlink_reload_down()
mlx5_unload_one_devl_locked()
mlx5_detach_device()
del_adev()
mlx5r_remove()
__mlx5_ib_remove()
mlx5_ib_roce_cleanup()
mlx5_remove_netdev_notifier()
unregister_netdevice_notifier (takes down_write(&pernet_ops_rwsem)

This deadlocks.

Resolve this by converting to register_netdevice_notifier_dev_net()
which does not take pernet_ops_rwsem and moves the notifier block around
according to netdev it takes as arg.

Use previously introduced netdev added/removed events to track uplink
netdev to be used for register_netdevice_notifier_dev_net() purposes.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 8b91babdd4c0..7394e7f36ba7 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -832,6 +832,9 @@ struct mlx5_roce {
 	rwlock_t		netdev_lock;
 	struct net_device	*netdev;
 	struct notifier_block	nb;
+	struct netdev_net_notifier nn;
+	struct notifier_block	mdev_nb;
+	struct net_device	*tracking_netdev;
 	atomic_t		tx_port_affinity;
 	enum ib_port_state last_port_state;
 	struct mlx5_ib_dev	*dev;