Re: [Xen-devel] [PATCH v2 2/2] hvc_xen: implement multiconsole support

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

> +static void xencons_disconnect_backend(struct xencons_info *info)
> +{
> +     if (info->irq > 0)
> +             unbind_from_irqhandler(info->irq, NULL);
> +     info->irq = 0;
> +     if (info->evtchn > 0)
> +             xenbus_free_evtchn(info->xbdev, info->evtchn);
> +     info->evtchn = 0;
> +     if (info->gntref > 0)
> +             gnttab_free_grant_references(info->gntref);
> +     info->gntref = 0;
> +     if (info->hvc != NULL)
> +             hvc_remove(info->hvc);
> +     info->hvc = NULL;
> +}
> +
> +static void xencons_free(struct xencons_info *info)
> +{
> +     xencons_disconnect_backend(info);
> +     free_page((unsigned long)info->intf);
> +     info->intf = NULL;
> +     info->vtermno = 0;
> +     kfree(info);
> +}
> +
> +static int xencons_remove(struct xenbus_device *dev)
> +{
> +     struct xencons_info *info = dev_get_drvdata(&dev->dev);
> +

I would say put
        xencons_disconnect_backend(info)

here, that way it calls hvc_remove first, and then this would
delete an "not-called" anymore structure.

> +     spin_lock(&xencons_lock);
> +     list_del(&info->list);
> +     spin_unlock(&xencons_lock);
> +     xencons_free(info);

>       return 0;
>  }
>

.. snip..
> +
> +static const struct xenbus_device_id xencons_ids[] = {
> +     { "console" },
> +     { "" }
> +};
> +
> +
>  static void __exit xen_hvc_fini(void)
>  {
> -     if (hvc)
> -             hvc_remove(hvc);
> +     struct xencons_info *entry, *next;
> +
> +     if (list_empty(&xenconsoles))
> +                     return;
> +
> +     spin_lock(&xencons_lock);

Take that spin-lock out.

> +     list_for_each_entry_safe(entry, next, &xenconsoles, list) {
> +             list_del(&entry->list);
> +             if (entry->xbdev)
> +                     xencons_remove(entry->xbdev);

This guy deletes itself from the list..
> +             else {
> +                     if (entry->irq > 0)
> +                             unbind_from_irqhandler(entry->irq, NULL);
> +                     if (entry->hvc);
> +                             hvc_remove(entry->hvc);
> +                     kfree(entry);

..but this one does not.  You could make xencons_remove just remove
itself from the list and nothing else. Then rename it to 
'xencons_remove_itself' perhaps?

After that, introduce a new function 'xencons_delete' that would call
xecons_disconnect_backend, xencons_remove_itself, and xencons_free?

> +             }
> +     }
> +     spin_unlock(&xencons_lock);
>  }
>  
>  static int xen_cons_init(void)
> @@ -256,18 +566,31 @@ static int xen_cons_init(void)
>       if (xen_initial_domain())
>               ops = &dom0_hvc_ops;
>       else {
> +             int r;
>               ops = &domU_hvc_ops;
>  
> -             if (xen_pv_domain())
> -                     console_evtchn = xen_start_info->console.domU.evtchn;
> +             if (xen_hvm_domain())
> +                     r = xen_hvm_console_init();
>               else
> -                     xen_hvm_console_init();
> +                     r = xen_pv_console_init();
> +             if (r < 0)
> +                     return r;
>       }
>  
>       hvc_instantiate(HVC_COOKIE, 0, ops);
>       return 0;
>  }
>  
> +static struct xenbus_driver xencons_driver = {

This needs to be wrapped in the new macro that Jan prepared.
DEFINE_XENBUS_DRIVER (73db144b58a32fc39733db6a7e1fe582072ad26a)

> +     .name = "xenconsole",
> +     .owner = THIS_MODULE,
> +     .ids = xencons_ids,
> +     .probe = xencons_probe,
> +     .remove = xencons_remove,
> +     .resume = xencons_resume,
> +     .otherend_changed = xencons_backend_changed,
> +};
> +
>  module_init(xen_hvc_init);
>  module_exit(xen_hvc_fini);
>  console_initcall(xen_cons_init);
> -- 
> 1.7.2.5

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