xen-netback: Don't destroy the netdev until the vif is shut down

[ upstream commit id: 279f438e36c0a70b23b86d2090aeec50155034a9 ]

Without this patch, if a frontend cycles through states Closing
and Closed (which Windows frontends need to do) then the netdev
will be destroyed and requires re-invocation of hotplug scripts
to restore state before the frontend can move to Connected. Thus
when udev is not in use the backend gets stuck in InitWait.

With this patch, the netdev is left alone whilst the backend is
still online and is only de-registered and freed just prior to
destroying the vif (which is also nicely symmetrical with the
netdev allocation and registration being done during probe) so
no re-invocation of hotplug scripts is required.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 9d7f1723dd8f750126337d7792a0614fea8ca601..1a285083d24ac01180e92679b3511cd1e797dd2d 100644 (file)
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -115,6 +115,7 @@ struct xenvif *xenvif_alloc(struct device *parent,
 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
                   unsigned long rx_ring_ref, unsigned int evtchn);
 void xenvif_disconnect(struct xenvif *vif);
+void xenvif_free(struct xenvif *vif);
 
 void xenvif_get(struct xenvif *vif);
 void xenvif_put(struct xenvif *vif);

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index d984141684857c1708085af50ad8fed208a06f85..3a294c2528d5a22af3d078aa688be3b0ec594cbc 100644 (file)
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -304,6 +304,9 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
        }
 
        netdev_dbg(dev, "Successfully created xenvif\n");
+
+       __module_get(THIS_MODULE);
+
        return vif;
 }
 
@@ -369,9 +372,14 @@ void xenvif_disconnect(struct xenvif *vif)
        if (vif->irq)
                unbind_from_irqhandler(vif->irq, vif);
 
-       unregister_netdev(vif->dev);
-
        xen_netbk_unmap_frontend_rings(vif);
+}
+
+void xenvif_free(struct xenvif *vif)
+{
+       unregister_netdev(vif->dev);
 
        free_netdev(vif->dev);
+
+       module_put(THIS_MODULE);
 }

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 410018c4c52818f0b3a697d64e4300a505825f91..abe24ff000f0d7a96a4f99a5a02183c16ac9bac9 100644 (file)
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -42,7 +42,7 @@ static int netback_remove(struct xenbus_device *dev)
        if (be->vif) {
                kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
                xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
-               xenvif_disconnect(be->vif);
+               xenvif_free(be->vif);
                be->vif = NULL;
        }
        kfree(be);
@@ -203,9 +203,18 @@ static void disconnect_backend(struct xenbus_device *dev)
 {
        struct backend_info *be = dev_get_drvdata(&dev->dev);
 
+       if (be->vif)
+               xenvif_disconnect(be->vif);
+}
+
+static void destroy_backend(struct xenbus_device *dev)
+{
+       struct backend_info *be = dev_get_drvdata(&dev->dev);
+
        if (be->vif) {
+               kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
                xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
-               xenvif_disconnect(be->vif);
+               xenvif_free(be->vif);
                be->vif = NULL;
        }
 }
@@ -237,14 +246,11 @@ static void frontend_changed(struct xenbus_device *dev,
        case XenbusStateConnected:
                if (dev->state == XenbusStateConnected)
                        break;
-               backend_create_xenvif(be);
                if (be->vif)
                        connect(be);
                break;
 
        case XenbusStateClosing:
-               if (be->vif)
-                       kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
                disconnect_backend(dev);
                xenbus_switch_state(dev, XenbusStateClosing);
                break;
@@ -253,6 +259,7 @@ static void frontend_changed(struct xenbus_device *dev,
                xenbus_switch_state(dev, XenbusStateClosed);
                if (xenbus_dev_is_online(dev))
                        break;
+               destroy_backend(dev);
                /* fall through if not online */
        case XenbusStateUnknown:
                device_unregister(&dev->dev);