1 files changed, 52 insertions, 21 deletions

diff --git a/drivers/base/faux.c b/drivers/base/faux.c
index 531e9d789ee0..a8329f88222e 100644
--- a/drivers/base/faux.c
+++ b/drivers/base/faux.c
@@ -25,12 +25,11 @@
 struct faux_object {
 	struct faux_device faux_dev;
 	const struct faux_device_ops *faux_ops;
+	const struct attribute_group **groups;
 };
 #define to_faux_object(dev) container_of_const(dev, struct faux_object, faux_dev.dev)
 
-static struct device faux_bus_root = {
-	.init_name	= "faux",
-};
+static struct device *faux_bus_root;
 
 static int faux_match(struct device *dev, const struct device_driver *drv)
 {
@@ -43,10 +42,21 @@ static int faux_probe(struct device *dev)
 	struct faux_object *faux_obj = to_faux_object(dev);
 	struct faux_device *faux_dev = &faux_obj->faux_dev;
 	const struct faux_device_ops *faux_ops = faux_obj->faux_ops;
-	int ret = 0;
+	int ret;
 
-	if (faux_ops && faux_ops->probe)
+	if (faux_ops && faux_ops->probe) {
 		ret = faux_ops->probe(faux_dev);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * Add groups after the probe succeeds to ensure resources are
+	 * initialized correctly
+	 */
+	ret = device_add_groups(dev, faux_obj->groups);
+	if (ret && faux_ops && faux_ops->remove)
+		faux_ops->remove(faux_dev);
 
 	return ret;
 }
@@ -57,6 +67,8 @@ static void faux_remove(struct device *dev)
 	struct faux_device *faux_dev = &faux_obj->faux_dev;
 	const struct faux_device_ops *faux_ops = faux_obj->faux_ops;
 
+	device_remove_groups(dev, faux_obj->groups);
+
 	if (faux_ops && faux_ops->remove)
 		faux_ops->remove(faux_dev);
 }
@@ -72,6 +84,7 @@ static struct device_driver faux_driver = {
 	.name		= "faux_driver",
 	.bus		= &faux_bus_type,
 	.probe_type	= PROBE_FORCE_SYNCHRONOUS,
+	.suppress_bind_attrs = true,
 };
 
 static void faux_device_release(struct device *dev)
@@ -102,7 +115,9 @@ static void faux_device_release(struct device *dev)
  *
  * Note, when this function is called, the functions specified in struct
  * faux_ops can be called before the function returns, so be prepared for
- * everything to be properly initialized before that point in time.
+ * everything to be properly initialized before that point in time.  If the
+ * probe callback (if one is present) does NOT succeed, the creation of the
+ * device will fail and NULL will be returned.
  *
  * Return:
  * * NULL if an error happened with creating the device
@@ -118,12 +133,16 @@ struct faux_device *faux_device_create_with_groups(const char *name,
 	struct device *dev;
 	int ret;
 
-	faux_obj = kzalloc(sizeof(*faux_obj), GFP_KERNEL);
+	if (!faux_bus_root)
+		return NULL;
+
+	faux_obj = kzalloc_obj(*faux_obj);
 	if (!faux_obj)
 		return NULL;
 
-	/* Save off the callbacks so we can use them in the future */
+	/* Save off the callbacks and groups so we can use them in the future */
 	faux_obj->faux_ops = faux_ops;
+	faux_obj->groups = groups;
 
 	/* Initialize the device portion and register it with the driver core */
 	faux_dev = &faux_obj->faux_dev;
@@ -134,10 +153,10 @@ struct faux_device *faux_device_create_with_groups(const char *name,
 	if (parent)
 		dev->parent = parent;
 	else
-		dev->parent = &faux_bus_root;
+		dev->parent = faux_bus_root;
 	dev->bus = &faux_bus_type;
-	dev->groups = groups;
 	dev_set_name(dev, "%s", name);
+	device_set_pm_not_required(dev);
 
 	ret = device_add(dev);
 	if (ret) {
@@ -147,6 +166,17 @@ struct faux_device *faux_device_create_with_groups(const char *name,
 		return NULL;
 	}
 
+	/*
+	 * Verify that we did bind the driver to the device (i.e. probe worked),
+	 * if not, let's fail the creation as trying to guess if probe was
+	 * successful is almost impossible to determine by the caller.
+	 */
+	if (!dev->driver) {
+		dev_dbg(dev, "probe did not succeed, tearing down the device\n");
+		faux_device_destroy(faux_dev);
+		faux_dev = NULL;
+	}
+
 	return faux_dev;
 }
 EXPORT_SYMBOL_GPL(faux_device_create_with_groups);
@@ -205,28 +235,29 @@ EXPORT_SYMBOL_GPL(faux_device_destroy);
 
 int __init faux_bus_init(void)
 {
+	struct device *root;
 	int ret;
 
-	ret = device_register(&faux_bus_root);
-	if (ret) {
-		put_device(&faux_bus_root);
-		return ret;
-	}
+	root = root_device_register("faux");
+	if (IS_ERR(root))
+		return PTR_ERR(root);
 
 	ret = bus_register(&faux_bus_type);
 	if (ret)
-		goto error_bus;
+		goto err_deregister_root;
 
 	ret = driver_register(&faux_driver);
 	if (ret)
-		goto error_driver;
+		goto err_deregister_bus;
 
-	return ret;
+	faux_bus_root = root;
+
+	return 0;
 
-error_driver:
+err_deregister_bus:
 	bus_unregister(&faux_bus_type);
+err_deregister_root:
+	root_device_unregister(root);
 
-error_bus:
-	device_unregister(&faux_bus_root);
 	return ret;
 }