[PATCH 09/10] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

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@xxxxxxxxxxxx>
---
 drivers/base/class.c   |   30 ++++++++++++++++++++++++---
 drivers/base/core.c    |   51 +++++++++++++++++++++++++----------------------
 include/linux/device.h |    2 +
 3 files changed, 55 insertions(+), 28 deletions(-)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index c4f8843..ed9393d 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -135,6 +135,17 @@ static void remove_class_attrs(struct class * cls)
 	}
 }
 
+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->subsys.kobj, tag_ops);
+}
+
 int class_register(struct class * cls)
 {
 	int error;
@@ -160,11 +171,22 @@ int class_register(struct class * cls)
 	cls->subsys.kobj.ktype = &class_ktype;
 
 	error = kset_register(&cls->subsys);
-	if (!error) {
-		error = add_class_attrs(class_get(cls));
-		class_put(cls);
-	}
+	if (error)
+		goto out;
+
+	error = class_setup_tagging(cls);
+	if (error)
+		goto out_unregister;
+
+	error = add_class_attrs(cls);
+	if (error)
+		goto out_unregister;
+
+out:
 	return error;
+out_unregister:
+	kset_unregister(&cls->subsys);
+	goto out;
 }
 
 void class_unregister(struct class * cls)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index a2c3d4e..f9d3fcf 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -600,16 +600,20 @@ static struct kobject *get_device_parent(struct device *dev,
 			return kobj;
 
 		/* or create a new class-directory at the parent device */
-		k = kobject_create(dev->class->name, parent_kobj);
-		if (!k)
+bser		kobj = kobject_create(dev->class->name, parent_kobj);
+		if (!kobj)
 			return NULL;
-		k->kset = &dev->class->class_dirs;
-		retval = kobject_register(k);
+		kobj->kset = &dev->class->class_dirs;
+		retval = kobject_register(kobj);
 		if (retval < 0) {
-			kfree(k);
+			kfree(kobj);
 			return NULL;
 		}
-		return k;
+		/* If we created a new class-directory setup tagging */
+		if (kobj && dev->class->tag_ops)
+			sysfs_enable_tagging(k, dev->class->tag_ops);
+
+		return kobj;
 	}
 
 	if (parent)
@@ -758,7 +762,8 @@ static void device_remove_class_symlinks(struct device *dev)
 
 	if (dev->kobj.parent != &dev->class->subsys.kobj &&
 	    dev->type != &part_type)
-		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+		sysfs_delete_link(&dev->class->subsys.kobj,
+				  &dev->kobj, dev->bus_id);
 #else
 	if (dev->parent && dev->type != &part_type)
 		sysfs_remove_link(&dev->kobj, "device");
@@ -1223,6 +1228,15 @@ int device_rename(struct device *dev, char *new_name)
 	strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
 	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
 
+#ifndef CONFIG_SYSFS_DEPRECATED
+	if (dev->class && (dev->kobj.parent != &dev->class->subsys.kobj)) {
+		error = sysfs_rename_link(&dev->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);
@@ -1231,24 +1245,13 @@ int device_rename(struct device *dev, char *new_name)
 
 #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) {
-		sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
-		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
-					  dev->bus_id);
-		if (error) {
-			dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
-				__FUNCTION__, error);
-		}
+		if (new_class_name)
+			error = sysfs_rename_link(&dev->parent->kobj,
+						  &dev->kobj,
+						  old_class_name,
+						  new_class_name);
 	}
 #endif
 
diff --git a/include/linux/device.h b/include/linux/device.h
index ed38712..80ba08f 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -187,6 +187,8 @@ struct class {
 
 	int	(*suspend)(struct device *, pm_message_t state);
 	int	(*resume)(struct device *);
+
+	const struct sysfs_tagged_dir_operations *tag_ops;
 };
 
 extern int __must_check class_register(struct class *);
-- 
1.5.3.rc6.17.g1911

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