From mboxrd@z Thu Jan 1 00:00:00 1970 From: jianhai luan Subject: Re: [Xen-devel] xen-netback notify DomU to send ARP. Date: Wed, 09 Jan 2013 20:28:05 +0800 Message-ID: <50ED6255.7020006@oracle.com> References: <50EC099D.6020407@oracle.com> <50EC297A02000078000B3BB5@nat28.tlf.novell.com> <1357652541.7989.179.camel@zakaz.uk.xensource.com> <50EC3DFD.8060206@oracle.com> <1357660834.12649.103.camel@dagon.hellion.org.uk> <50ED1EB3.3080605@oracle.com> <50ED4F1D02000078000B3F87@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------090002070100000502000305" Cc: xen-devel@lists.xensource.com, netdev@vger.kernel.org, Jan Beulich , Konrad Rzeszutek Wilk To: Jan Beulich Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:26424 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757608Ab3AIM21 (ORCPT ); Wed, 9 Jan 2013 07:28:27 -0500 In-Reply-To: <50ED4F1D02000078000B3F87@nat28.tlf.novell.com> Sender: netdev-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------090002070100000502000305 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 2013-1-9 18:06, Jan Beulich wrote: >>>> On 09.01.13 at 08:39, jianhai luan 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: > --------------090002070100000502000305 Content-Type: text/plain; charset=gb18030; name="0001-xen-netback-notify-DomU-to-send-ARP.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="0001-xen-netback-notify-DomU-to-send-ARP.patch" >>From a64d80cc0c780bee7a8d6e842126cb5f7d17f0d2 Mon Sep 17 00:00:00 2001 From: Jason Luan Date: Fri, 28 Dec 2012 15:43:06 +0800 Subject: [PATCH] xen-netback notify DomU to send ARP. When Xen Dom0's network circumstance changed, DomU should be notified in some special condition. For example the below circumstance: ping from Guest A to DomU: Guest A --> eth0 - bond0 - xenbr0 --VIF(DOMU) eth1 / when eth0 inactive, and eth1 active. Guest A --> eth0 bond0 - xenbr0 --VIF(DOMU) eth1 / Guest A will don't reach to DomU. After Guest A send ARP request and DomU respond, Guest A will reach DomU. But some more second will be elapsed. eth0 bond0 - xenbr0 --VIF(DOMU) Guest A --> eth1/ If Xen netback watch the network change, will notify DomU by change it own status. So netfront will watch netback's change, and DomU send ARP initiative. Signed-off-by: Jason Luan --- drivers/net/xen-netback/xenbus.c | 33 +++++++++++++++++++++++++++++++++ 1 files changed, 33 insertions(+), 0 deletions(-) diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 410018c..17a3990 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -26,6 +26,7 @@ struct backend_info { struct xenvif *vif; enum xenbus_state frontend_state; struct xenbus_watch hotplug_status_watch; + struct notifier_block vif_notifier; u8 have_hotplug_status_watch:1; }; @@ -34,11 +35,39 @@ 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 = ptr; + 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) + return NOTIFY_DONE; + + switch (event) { + case NETDEV_NOTIFY_PEERS: + /* Notify frontend to Send gratuitous ARP */ + xenbus_switch_state(be->dev, XenbusStateInitialised); + xenbus_switch_state(be->dev, XenbusStateConnected); + break; + } + + 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 +158,10 @@ static int netback_probe(struct xenbus_device *dev, /* This kicks hotplug scripts, so do it immediately. */ backend_create_xenvif(be); + /* Register Frontend Event Notify */ + be->vif_notifier.notifier_call = netback_netdev_event; + register_netdevice_notifier(&be->vif_notifier); + return 0; abort_transaction: -- 1.7.6.5 --------------090002070100000502000305--