xen: add backend driver support

Impact: backend device support

Add the basic machinery to support backend drivers.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[corresponds to 79727b851bac in git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 30 insertions, 9 deletions

diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 04c4f0123521..dd31d5a43b40 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -62,6 +62,17 @@ static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type, con
         return err;
 }
 
+static int xenbus_uevent_frontend(struct device *_dev, struct kobj_uevent_env *env)
+{
+        struct xenbus_device *dev = to_xenbus_device(_dev);
+
+        if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
+                return -ENOMEM;
+
+        return 0;
+}
+
+
 static void backend_changed(struct xenbus_watch *watch,
                             const char **vec, unsigned int len)
 {
@@ -81,7 +92,7 @@ static struct xen_bus_type xenbus_frontend = {
         .bus = {
                 .name     = "xen",
                 .match    = xenbus_match,
-                .uevent   = xenbus_uevent,
+                .uevent   = xenbus_uevent_frontend,
                 .probe    = xenbus_dev_probe,
                 .remove   = xenbus_dev_remove,
                 .shutdown = xenbus_dev_shutdown,
@@ -232,8 +243,25 @@ int __xenbus_register_frontend(struct xenbus_driver *drv,
 }
 EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
 
+static int frontend_probe_and_watch(struct notifier_block *notifier,
+                                   unsigned long event,
+                                   void *data)
+{
+        /* Enumerate devices in xenstore and watch for changes. */
+        xenbus_probe_devices(&xenbus_frontend);
+        printk(KERN_CRIT "%s devices probed ok\n", __func__);
+        register_xenbus_watch(&fe_watch);
+        printk(KERN_CRIT "%s watch add ok ok\n", __func__);
+        printk(KERN_CRIT "%s all done\n", __func__);
+        return NOTIFY_DONE;
+}
+
+
 static int __init xenbus_probe_frontend_init(void)
 {
+        static struct notifier_block xenstore_notifier = {
+                .notifier_call = frontend_probe_and_watch
+        };
         int err;
 
         DPRINTK("");
@@ -246,14 +274,7 @@ static int __init xenbus_probe_frontend_init(void)
         }
         printk(KERN_CRIT "%s bus registered ok\n", __func__);
 
-        if (!xen_initial_domain()) {
-                /* Enumerate devices in xenstore and watch for changes. */
-                xenbus_probe_devices(&xenbus_frontend);
-                printk(KERN_CRIT "%s devices probed ok\n", __func__);
-                register_xenbus_watch(&fe_watch);
-                printk(KERN_CRIT "%s watch add ok ok\n", __func__);
-                printk(KERN_CRIT "%s all done\n", __func__);
-        }
+        register_xenstore_notifier(&xenstore_notifier);
 
         return 0;
 }