Driver core: fix deprectated sysfs structure for nested class devices

Nested class devices used to have 'device' symlink point to a real
(physical) device instead of a parent class device.  When converting
subsystems to struct device we need to keep doing what class devices did if
CONFIG_SYSFS_DEPRECATED is Y, otherwise parts of udev break.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Greg KH <greg@kroah.com>
Tested-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/core.c

@@ -679,14 +679,26 @@ static int device_add_class_symlinks(struct device *dev)
 			goto out_subsys;
 	}
 	if (dev->parent) {
-		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
-					  "device");
-		if (error)
-			goto out_busid;
 #ifdef CONFIG_SYSFS_DEPRECATED
 		{
-			char * class_name = make_class_name(dev->class->name,
-								&dev->kobj);
+			struct device *parent = dev->parent;
+			char *class_name;
+
+			/*
+			 * In old sysfs stacked class devices had 'device'
+			 * link pointing to real device instead of parent
+			 */
+			while (parent->class && !parent->bus && parent->parent)
+				parent = parent->parent;
+
+			error = sysfs_create_link(&dev->kobj,
+						  &parent->kobj,
+						  "device");
+			if (error)
+				goto out_busid;
+
+			class_name = make_class_name(dev->class->name,
+							&dev->kobj);
 			if (class_name)
 				error = sysfs_create_link(&dev->parent->kobj,
 							&dev->kobj, class_name);
@@ -694,6 +706,11 @@ static int device_add_class_symlinks(struct device *dev)
 			if (error)
 				goto out_device;
 		}
+#else
+		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
+					  "device");
+		if (error)
+			goto out_busid;
 #endif
 	}
 	return 0;