driver core fixes: make_class_name() retval checks

Make make_class_name() return NULL on error and fixup callers in the
driver core.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index c60114d..6fee3e6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -527,9 +527,13 @@
 					  &dev->kobj, dev->bus_id);
 #ifdef CONFIG_SYSFS_DEPRECATED
 		if (parent) {
-			sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
-			class_name = make_class_name(dev->class->name, &dev->kobj);
-			sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
+			sysfs_create_link(&dev->kobj, &dev->parent->kobj,
+							"device");
+			class_name = make_class_name(dev->class->name,
+							&dev->kobj);
+			if (class_name)
+				sysfs_create_link(&dev->parent->kobj,
+						  &dev->kobj, class_name);
 		}
 #endif
 	}
@@ -672,7 +676,9 @@
 		if (parent) {
 			char *class_name = make_class_name(dev->class->name,
 							   &dev->kobj);
-			sysfs_remove_link(&dev->parent->kobj, class_name);
+			if (class_name)
+				sysfs_remove_link(&dev->parent->kobj,
+						  class_name);
 			kfree(class_name);
 			sysfs_remove_link(&dev->kobj, "device");
 		}
@@ -975,8 +981,7 @@
 
 	class_name = make_class_name(dev->class->name, &dev->kobj);
 	if (!class_name) {
-		error = PTR_ERR(class_name);
-		class_name = NULL;
+		error = -ENOMEM;
 		goto out;
 	}
 	if (old_parent) {