net/mlx5: Use devl_ API in mlx5e_devlink_port_register

As part of the flows invoked by mlx5_devlink_eswitch_mode_set() get to
mlx5_rescan_drivers_locked() which can call mlx5e_probe()/mlx5e_remove
and register/unregister mlx5e driver ports accordingly. This can lead to
deadlock once mlx5_devlink_eswitch_mode_set() will use devlink lock.
Use devl_port_register/unregister() instead of
devlink_port_register/unregister() and add devlink instance locks in the
driver paths to this function to have it locked while calling devl_ API
function.

If remove or probe were called by module init or module cleanup flows,
need to lock devlink just before calling devl_port_register(), otherwise
it is called by attach/detach or register/unregister flow and we can
have the flow locked. Added flag to distinguish between these cases.

This will be used by the downstream patch to invoke
mlx5_devlink_eswitch_mode_set() with devlink locked.

Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 27 insertions, 2 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/dev.c b/drivers/net/ethernet/mellanox/mlx5/core/dev.c
index 50422b56a64d..ccf2068d2e79 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/dev.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/dev.c
@@ -335,13 +335,16 @@ static void del_adev(struct auxiliary_device *adev)
 
 int mlx5_attach_device(struct mlx5_core_dev *dev)
 {
+	struct devlink *devlink = priv_to_devlink(dev);
 	struct mlx5_priv *priv = &dev->priv;
 	struct auxiliary_device *adev;
 	struct auxiliary_driver *adrv;
 	int ret = 0, i;
 
+	devl_lock(devlink);
 	mutex_lock(&mlx5_intf_mutex);
 	priv->flags &= ~MLX5_PRIV_FLAGS_DETACH;
+	priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
 	for (i = 0; i < ARRAY_SIZE(mlx5_adev_devices); i++) {
 		if (!priv->adev[i]) {
 			bool is_supported = false;
@@ -389,19 +392,24 @@ int mlx5_attach_device(struct mlx5_core_dev *dev)
 			break;
 		}
 	}
+	priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
 	mutex_unlock(&mlx5_intf_mutex);
+	devl_unlock(devlink);
 	return ret;
 }
 
 void mlx5_detach_device(struct mlx5_core_dev *dev)
 {
+	struct devlink *devlink = priv_to_devlink(dev);
 	struct mlx5_priv *priv = &dev->priv;
 	struct auxiliary_device *adev;
 	struct auxiliary_driver *adrv;
 	pm_message_t pm = {};
 	int i;
 
+	devl_lock(devlink);
 	mutex_lock(&mlx5_intf_mutex);
+	priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
 	for (i = ARRAY_SIZE(mlx5_adev_devices) - 1; i >= 0; i--) {
 		if (!priv->adev[i])
 			continue;
@@ -430,18 +438,24 @@ skip_suspend:
 		del_adev(&priv->adev[i]->adev);
 		priv->adev[i] = NULL;
 	}
+	priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
 	priv->flags |= MLX5_PRIV_FLAGS_DETACH;
 	mutex_unlock(&mlx5_intf_mutex);
+	devl_unlock(devlink);
 }
 
 int mlx5_register_device(struct mlx5_core_dev *dev)
 {
+	struct devlink *devlink;
 	int ret;
 
+	devlink = priv_to_devlink(dev);
+	devl_lock(devlink);
 	mutex_lock(&mlx5_intf_mutex);
 	dev->priv.flags &= ~MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV;
 	ret = mlx5_rescan_drivers_locked(dev);
 	mutex_unlock(&mlx5_intf_mutex);
+	devl_unlock(devlink);
 	if (ret)
 		mlx5_unregister_device(dev);
 
@@ -450,10 +464,15 @@ int mlx5_register_device(struct mlx5_core_dev *dev)
 
 void mlx5_unregister_device(struct mlx5_core_dev *dev)
 {
+	struct devlink *devlink;
+
+	devlink = priv_to_devlink(dev);
+	devl_lock(devlink);
 	mutex_lock(&mlx5_intf_mutex);
 	dev->priv.flags = MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV;
 	mlx5_rescan_drivers_locked(dev);
 	mutex_unlock(&mlx5_intf_mutex);
+	devl_unlock(devlink);
 }
 
 static int add_drivers(struct mlx5_core_dev *dev)
@@ -526,16 +545,22 @@ del_adev:
 int mlx5_rescan_drivers_locked(struct mlx5_core_dev *dev)
 {
 	struct mlx5_priv *priv = &dev->priv;
+	int err = 0;
 
 	lockdep_assert_held(&mlx5_intf_mutex);
 	if (priv->flags & MLX5_PRIV_FLAGS_DETACH)
 		return 0;
 
+	priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
 	delete_drivers(dev);
 	if (priv->flags & MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV)
-		return 0;
+		goto out;
+
+	err = add_drivers(dev);
 
-	return add_drivers(dev);
+out:
+	priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
+	return err;
 }
 
 bool mlx5_same_hw_devs(struct mlx5_core_dev *dev, struct mlx5_core_dev *peer_dev)