On Thu, Apr 30, 2020 at 11:44:42PM +0200, Guoqing Jiang wrote: > +/** > + * attach_page_private - attach data to page's private field and set PG_private. > + * @page: page to be attached and set flag. > + * @data: data to attach to page's private field. > + * > + * Need to take reference as mm.h said "Setting PG_private should also increment > + * the refcount". > + */ I don't think this will read well when added to the API documentation. Try this: /** * attach_page_private - Attach private data to a page. * @page: Page to attach data to. * @data: Data to attach to page. * * Attaching private data to a page increments the page's reference count. * The data must be detached before the page will be freed. */ > +/** > + * clear_page_private - clear page's private field and PG_private. > + * @page: page to be cleared. > + * > + * The counterpart function of attach_page_private. > + * Return: private data of page or NULL if page doesn't have private data. > + */ Seems to me that the opposite of "attach" is "detach", not "clear". /** * detach_page_private - Detach private data from a page. * @page: Page to detach data from. * * Removes the data that was previously attached to the page and decrements * the refcount on the page. * * Return: Data that was attached to the page. */