@@ -3458,6 +3458,122 @@ int device_move(struct device *dev, struct device *new_parent,
}
EXPORT_SYMBOL_GPL(device_move);
+static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
+ kgid_t kgid)
+{
+ struct kobject *kobj = &dev->kobj;
+ struct class *class = dev->class;
+ const struct device_type *type = dev->type;
+ int error;
+
+ if (class) {
+ /*
+ * Change the device groups of the device class for @dev to
+ * @kuid/@kgid.
+ */
+ error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
+ kgid);
+ if (error)
+ return error;
+ }
+
+ if (type) {
+ /*
+ * Change the device groups of the device type for @dev to
+ * @kuid/@kgid.
+ */
+ error = sysfs_groups_change_owner(kobj, type->groups, kuid,
+ kgid);
+ if (error)
+ return error;
+ }
+
+ /* Change the device groups of @dev to @kuid/@kgid. */
+ error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
+ if (error)
+ return error;
+
+ if (device_supports_offline(dev) && !dev->offline_disabled) {
+ /* Change online device attributes of @dev to @kuid/@kgid. */
+ error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
+ kuid, kgid);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
+/**
+ * device_change_owner - change the owner of an existing device.
+ * @dev: device.
+ * @kuid: new owner's kuid
+ * @kgid: new owner's kgid
+ *
+ * This changes the owner of @dev and its corresponding sysfs entries to
+ * @kuid/@kgid. This function closely mirrors how @dev was added via driver
+ * core.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
+{
+ int error;
+ struct kobject *kobj = &dev->kobj;
+
+ dev = get_device(dev);
+ if (!dev)
+ return -EINVAL;
+
+ /*
+ * Change the kobject and the default attributes and groups of the
+ * ktype associated with it to @kuid/@kgid.
+ */
+ error = sysfs_change_owner(kobj, kuid, kgid);
+ if (error)
+ goto out;
+
+ /*
+ * Change the uevent file for @dev to the new owner. The uevent file
+ * was created in a separate step when @dev got added and we mirror
+ * that step here.
+ */
+ error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
+ kgid);
+ if (error)
+ goto out;
+
+ /*
+ * Change the device groups, the device groups associated with the
+ * device class, and the groups associated with the device type of @dev
+ * to @kuid/@kgid.
+ */
+ error = device_attrs_change_owner(dev, kuid, kgid);
+ if (error)
+ goto out;
+
+#ifdef CONFIG_BLOCK
+ if (sysfs_deprecated && dev->class == &block_class)
+ goto out;
+#endif
+
+ /*
+ * Change the owner of the symlink located in the class directory of
+ * the device class associated with @dev which points to the actual
+ * directory entry for @dev to @kuid/@kgid. This ensures that the
+ * symlink shows the same permissions as its target.
+ */
+ error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
+ dev_name(dev), kuid, kgid);
+ if (error)
+ goto out;
+
+out:
+ put_device(dev);
+ return error;
+}
+EXPORT_SYMBOL_GPL(device_change_owner);
+
/**
* device_shutdown - call ->shutdown() on each device to shutdown.
*/
@@ -817,6 +817,7 @@ extern struct device *device_find_child_by_name(struct device *parent,
extern int device_rename(struct device *dev, const char *new_name);
extern int device_move(struct device *dev, struct device *new_parent,
enum dpm_order dpm_order);
+extern int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid);
extern const char *device_get_devnode(struct device *dev,
umode_t *mode, kuid_t *uid, kgid_t *gid,
const char **tmp);