Re: [Xen-devel] [PATCH v3 14/18] xen/pvcalls: disconnect and module_exit

[Juergen Gross <jgross@xxxxxxxx>]

On 02/06/17 21:31, Stefano Stabellini wrote:
> Implement backend_disconnect. Call pvcalls_back_release_active on active
> sockets and pvcalls_back_release_passive on passive sockets.
> 
> Implement module_exit by calling backend_disconnect on frontend
> connections.
> 
> Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> CC: boris.ostrovsky@xxxxxxxxxx
> CC: jgross@xxxxxxxx
> ---
>  drivers/xen/pvcalls-back.c | 49 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
> 
> diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> index b541887..6afe7a0 100644
> --- a/drivers/xen/pvcalls-back.c
> +++ b/drivers/xen/pvcalls-back.c
> @@ -800,6 +800,38 @@ static int backend_connect(struct xenbus_device *dev)
>  
>  static int backend_disconnect(struct xenbus_device *dev)
>  {
> +     struct pvcalls_fedata *priv;
> +     struct sock_mapping *map, *n;
> +     struct sockpass_mapping *mappass;
> +     struct radix_tree_iter iter;
> +     void **slot;
> +
> +
> +     priv = dev_get_drvdata(&dev->dev);
> +
> +     list_for_each_entry_safe(map, n, &priv->socket_mappings, list) {
> +             pvcalls_back_release_active(dev, priv, map);
> +     }

You can drop the {}

> +
> +     radix_tree_for_each_slot(slot, &priv->socketpass_mappings, &iter, 0) {
> +             mappass = radix_tree_deref_slot(slot);
> +             if (!mappass || radix_tree_exception(mappass)) {

This looks fishy.

You might call radix_tree_deref_retry(NULL). Right now this is okay,
but you depend on the radix tree internals here.

> +                     if (radix_tree_deref_retry(mappass)) {
> +                             slot = radix_tree_iter_retry(&iter);
> +                             continue;

The continue; statement is pointless here.

> +                     }
> +             } else
> +                     pvcalls_back_release_passive(dev, priv, mappass);
> +     }
> +
> +     xenbus_unmap_ring_vfree(dev, (void *)priv->sring);

Drop the cast.

> +     unbind_from_irqhandler(priv->irq, dev);
> +
> +     list_del(&priv->list);
> +     destroy_workqueue(priv->wq);
> +     kfree(priv);
> +     dev_set_drvdata(&dev->dev, NULL);
> +
>       return 0;
>  }
>  
> @@ -993,3 +1025,20 @@ static int __init pvcalls_back_init(void)
>       return 0;
>  }
>  module_init(pvcalls_back_init);
> +
> +static void __exit pvcalls_back_fin(void)
> +{
> +     struct pvcalls_fedata *priv, *npriv;
> +
> +     down(&pvcalls_back_global.frontends_lock);
> +     list_for_each_entry_safe(priv, npriv, &pvcalls_back_global.frontends,
> +                              list) {
> +             backend_disconnect(priv->dev);
> +     }
> +     up(&pvcalls_back_global.frontends_lock);
> +
> +     xenbus_unregister_driver(&pvcalls_back_driver);
> +     memset(&pvcalls_back_global, 0, sizeof(pvcalls_back_global));

Why?


Juergen

> +}
> +
> +module_exit(pvcalls_back_fin);
> 


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