driver core: Implement tagged directory support for device classes.

This patch enables tagging on every class directory if struct class
has tag_ops.

In addition device_del and device_rename were modified to use
sysfs_delete_link and sysfs_rename_link respectively to ensure
when these operations happen on devices whose classes have
tag_ops that they work properly.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
---
 drivers/base/class.c   |   30 ++++++++++++++++++++++++++----
 drivers/base/core.c    |   41 +++++++++++++++++++++++------------------
 include/linux/device.h |    2 ++
 3 files changed, 51 insertions(+), 22 deletions(-)

Index: linux-mm/drivers/base/class.c
===================================================================
--- linux-mm.orig/drivers/base/class.c
+++ linux-mm/drivers/base/class.c
@@ -135,6 +135,17 @@ static void remove_class_attrs(struct cl
 	}
 }
 
+static int class_setup_tagging(struct class *cls)
+{
+	const struct sysfs_tagged_dir_operations *tag_ops;
+
+	tag_ops = cls->tag_ops;
+	if (!tag_ops)
+		return 0;
+
+	return sysfs_enable_tagging(&cls->p->class_subsys.kobj, tag_ops);
+}
+
 int __class_register(struct class *cls, struct lock_class_key *key)
 {
 	struct class_private *cp;
@@ -171,13 +182,24 @@ int __class_register(struct class *cls, 
 	cls->p = cp;
 
 	error = kset_register(&cp->class_subsys);
-	if (error) {
-		kfree(cp);
-		return error;
-	}
+	if (error)
+		goto out_free_cp;
+
+	error = class_setup_tagging(cls);
+	if (error)
+		goto out_unregister;
+
 	error = add_class_attrs(class_get(cls));
 	class_put(cls);
+	if (error)
+		goto out_unregister;
+out:
 	return error;
+out_unregister:
+	kset_unregister(&cp->class_subsys);
+out_free_cp:
+	kfree(cp);
+	goto out;
 }
 EXPORT_SYMBOL_GPL(__class_register);
 
Index: linux-mm/drivers/base/core.c
===================================================================
--- linux-mm.orig/drivers/base/core.c
+++ linux-mm/drivers/base/core.c
@@ -618,6 +618,10 @@ static struct kobject *get_device_parent
 			kobject_put(k);
 			return NULL;
 		}
+		/* If we created a new class-directory setup tagging */
+		if (dev->class->tag_ops)
+			sysfs_enable_tagging(k, dev->class->tag_ops);
+
 		/* do not emit an uevent for this simple "glue" directory */
 		return k;
 	}
@@ -754,13 +758,14 @@ static void device_remove_class_symlinks
 
 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
+		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
 				  dev_name(dev));
 #else
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
 
-	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
+			  dev_name(dev));
 #endif
 
 	sysfs_remove_link(&dev->kobj, "subsystem");
@@ -1349,6 +1354,16 @@ int device_rename(struct device *dev, ch
 	strlcpy(old_device_name, dev_name(dev), BUS_ID_SIZE);
 	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
 
+#ifndef CONFIG_SYSFS_DEPRECATED
+	if (dev->class &&
+	    (dev->kobj.parent != &dev->class->p->class_subsys.kobj)) {
+		error = sysfs_rename_link(&dev->class->p->class_subsys.kobj,
+			&dev->kobj, old_device_name, new_name);
+		if (error)
+			goto out;
+	}
+#endif
+
 	error = kobject_rename(&dev->kobj, new_name);
 	if (error) {
 		strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
@@ -1357,23 +1372,13 @@ int device_rename(struct device *dev, ch
 
 #ifdef CONFIG_SYSFS_DEPRECATED
 	if (old_class_name) {
+		error = -ENOMEM;
 		new_class_name = make_class_name(dev->class->name, &dev->kobj);
-		if (new_class_name) {
-			error = sysfs_create_link(&dev->parent->kobj,
-						  &dev->kobj, new_class_name);
-			if (error)
-				goto out;
-			sysfs_remove_link(&dev->parent->kobj, old_class_name);
-		}
-	}
-#else
-	if (dev->class) {
-		error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
-					  &dev->kobj, dev_name(dev));
-		if (error)
-			goto out;
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
-				  old_device_name);
+		if (new_class_name)
+			error = sysfs_rename_link(&dev->parent->kobj,
+						  &dev->kobj,
+						  old_class_name,
+						  new_class_name);
 	}
 #endif
 
Index: linux-mm/include/linux/device.h
===================================================================
--- linux-mm.orig/include/linux/device.h
+++ linux-mm/include/linux/device.h
@@ -195,6 +195,8 @@ struct class {
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
 
+	const struct sysfs_tagged_dir_operations *tag_ops;
+
 	struct pm_ops *pm;
 	struct class_private *p;
 };

-- 
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