Re: [RFC PATCH 1/9] include/linux/pagemap.h: introduce set/clear_fs_page_private

[Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>]

Hi Christoph,

On 4/27/20 7:52 AM, Christoph Hellwig wrote:
> Why not attach_page_private and clear_page_private as that conveys
> the use case a little better?

Yes, thanks for the good suggestion. Will rename them if no one else
has new idea ...

> > +static inline void *set_fs_page_private(struct page *page, void *data)
> > +{
> > +	get_page(page);
> > +	set_page_private(page, (unsigned long)data);
> > +	SetPagePrivate(page);
> > +
> > +	return data;
> > +}
> > +
> > +static inline void *clear_fs_page_private(struct page *page)
> > +{
> > +	void *data = (void *)page_private(page);
> > +
> > +	if (!PagePrivate(page))
> > +		return NULL;
> > +	ClearPagePrivate(page);
> > +	set_page_private(page, 0);
> > +	put_page(page);
> > +
> > +	return data;
> > +}
> Can you add kerneldoc comments describing them, including why we
> take the refernces?

Ok, will do.

> Also what is the point of the return value of set_fs_page_private?

In this way, iomap_page_create can just return the function, but you
don't like this way as you replied, will change the return value to "void".

Thanks,
Guoqing