1 files changed, 98 insertions, 1 deletions

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index c8f0282bb649..97f0d234482d 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -206,6 +206,65 @@ void xenbus_otherend_changed(struct xenbus_watch *watch,
 }
 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
 
+#define XENBUS_SHOW_STAT(name)						\
+static ssize_t show_##name(struct device *_dev,				\
+			   struct device_attribute *attr,		\
+			   char *buf)					\
+{									\
+	struct xenbus_device *dev = to_xenbus_device(_dev);		\
+									\
+	return sprintf(buf, "%d\n", atomic_read(&dev->name));		\
+}									\
+static DEVICE_ATTR(name, 0444, show_##name, NULL)
+
+XENBUS_SHOW_STAT(event_channels);
+XENBUS_SHOW_STAT(events);
+XENBUS_SHOW_STAT(spurious_events);
+XENBUS_SHOW_STAT(jiffies_eoi_delayed);
+
+static ssize_t show_spurious_threshold(struct device *_dev,
+				       struct device_attribute *attr,
+				       char *buf)
+{
+	struct xenbus_device *dev = to_xenbus_device(_dev);
+
+	return sprintf(buf, "%d\n", dev->spurious_threshold);
+}
+
+static ssize_t set_spurious_threshold(struct device *_dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct xenbus_device *dev = to_xenbus_device(_dev);
+	unsigned int val;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	dev->spurious_threshold = val;
+
+	return count;
+}
+
+static DEVICE_ATTR(spurious_threshold, 0644, show_spurious_threshold,
+		   set_spurious_threshold);
+
+static struct attribute *xenbus_attrs[] = {
+	&dev_attr_event_channels.attr,
+	&dev_attr_events.attr,
+	&dev_attr_spurious_events.attr,
+	&dev_attr_jiffies_eoi_delayed.attr,
+	&dev_attr_spurious_threshold.attr,
+	NULL
+};
+
+static const struct attribute_group xenbus_group = {
+	.name = "xenbus",
+	.attrs = xenbus_attrs,
+};
+
 int xenbus_dev_probe(struct device *_dev)
 {
 	struct xenbus_device *dev = to_xenbus_device(_dev);
@@ -253,6 +312,11 @@ int xenbus_dev_probe(struct device *_dev)
 		return err;
 	}
 
+	dev->spurious_threshold = 1;
+	if (sysfs_create_group(&dev->dev.kobj, &xenbus_group))
+		dev_warn(&dev->dev, "sysfs_create_group on %s failed.\n",
+			 dev->nodename);
+
 	return 0;
 fail_put:
 	module_put(drv->driver.owner);
@@ -269,6 +333,8 @@ int xenbus_dev_remove(struct device *_dev)
 
 	DPRINTK("%s", dev->nodename);
 
+	sysfs_remove_group(&dev->dev.kobj, &xenbus_group);
+
 	free_otherend_watch(dev);
 
 	if (drv->remove) {
@@ -683,7 +749,7 @@ void unregister_xenstore_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 
-void xenbus_probe(void)
+static void xenbus_probe(void)
 {
 	xenstored_ready = 1;
 
@@ -714,6 +780,23 @@ static bool xs_hvm_defer_init_for_callback(void)
 #endif
 }
 
+static int xenbus_probe_thread(void *unused)
+{
+	DEFINE_WAIT(w);
+
+	/*
+	 * We actually just want to wait for *any* trigger of xb_waitq,
+	 * and run xenbus_probe() the moment it occurs.
+	 */
+	prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
+	schedule();
+	finish_wait(&xb_waitq, &w);
+
+	DPRINTK("probing");
+	xenbus_probe();
+	return 0;
+}
+
 static int __init xenbus_probe_initcall(void)
 {
 	/*
@@ -725,6 +808,20 @@ static int __init xenbus_probe_initcall(void)
 	     !xs_hvm_defer_init_for_callback()))
 		xenbus_probe();
 
+	/*
+	 * For XS_LOCAL, spawn a thread which will wait for xenstored
+	 * or a xenstore-stubdom to be started, then probe. It will be
+	 * triggered when communication starts happening, by waiting
+	 * on xb_waitq.
+	 */
+	if (xen_store_domain_type == XS_LOCAL) {
+		struct task_struct *probe_task;
+
+		probe_task = kthread_run(xenbus_probe_thread, NULL,
+					 "xenbus_probe");
+		if (IS_ERR(probe_task))
+			return PTR_ERR(probe_task);
+	}
 	return 0;
 }
 device_initcall(xenbus_probe_initcall);