Re: [Xen-devel] xen-netback notify DomU to send ARP.

[jianhai luan <jianhai.luan@xxxxxxxxxx>]

On 2013-1-9 18:06, Jan Beulich wrote:
> > > > On 09.01.13 at 08:39, jianhai luan <jianhai.luan@xxxxxxxxxx> wrote:
> > @@ -34,11 +35,42 @@ static void connect(struct backend_info *);
> > static void backend_create_xenvif(struct backend_info *be);
> > static void unregister_hotplug_status_watch(struct backend_info *be);
> >
> > +#define nb_to_backend(nb) container_of(nb, struct backend_info, vif_notifier)
> > +/**
> > + * When network condition of vif change, notify the frontend.
> > + */
> > +static int netback_netdev_event(struct notifier_block *this,
> > +                               unsigned long event, void *ptr)
> > +{
> > +       struct net_device *event_dev = (struct net_device *)ptr;
> Pointless cast.
>
> > +       struct backend_info *be = nb_to_backend(this);
> > +
> > +       pr_debug("event_dev: %s, event: %lx\n",
> > +                event_dev ? event_dev->name : "None", event);
> > +
> > +       if (!be->vif)
> > +               goto out;
> > +
> > +       switch (event) {
> > +       case NETDEV_NOTIFY_PEERS:
> > +               /* Notify frontend to Send gratuitous ARP */
> > +               xenbus_switch_state(be->dev, XenbusStateInitialised);
> > +               xenbus_switch_state(be->dev, );
> This is the sort of change that clearly isn't acceptable, as I don't
> think you have ways to check _all_ existing frontends for their
> compatibility with this. A connected -> connected transition
> might be acceptable (that was done in the block frontend too, for
> implementing dynamic resize), but will likely need to be
> accompanied by a frontend side patch to handle that (which so
> far should be a no-op).
The latest xen net-frontent driver have handled the condition. State 
XenbusStateInitialised will do nothing,
but change to XenbusStateConnected will trigger 
netdev_notify_peers(netdev) to send ARP.
> > +               break;
> > +       default:
> > +               break;
> Pointless default case.
>
> > +       }
> > +
> > +out:
> I don't think you really need the label (and the goto above) - just
> put a return there.
>
> > +       return NOTIFY_DONE;
> > +}
> > +
> > static int netback_remove(struct xenbus_device *dev)
> > {
> >         struct backend_info *be = dev_get_drvdata(&dev->dev);
> >
> >         unregister_hotplug_status_watch(be);
> > +       unregister_netdevice_notifier(&be->vif_notifier);
> >         if (be->vif) {
> >                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
> >                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
> > @@ -129,6 +161,10 @@ static int netback_probe(struct xenbus_device *dev,
> >         /* This kicks hotplug scripts, so do it immediately. */
> >         backend_create_xenvif(be);
> >
> > +       /*   Event Notify */
> > +       (be->vif_notifier).notifier_call = netback_netdev_event;
> Pointless parentheses.
>
> Jan
>
> > +       register_netdevice_notifier(&be->vif_notifier);
> > +
> >         return 0;
> >
> > abort_transaction:

Attachment: 0001-xen-netback-notify-DomU-to-send-ARP.patch
Description: Text document

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