Re: [PATCH v4 09/25] mm: Add folio_index, folio_page and folio_contains

[Christoph Hellwig]

On Sat, Mar 13, 2021 at 12:37:16PM -0800, Andrew Morton wrote:
> On Fri,  5 Mar 2021 04:18:45 +0000 "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> wrote:
> 
> > folio_index() is the equivalent of page_index() for folios.  folio_page()
> > finds the page in a folio for a page cache index.  folio_contains()
> > tells you whether a folio contains a particular page cache index.
> > 
> 
> copy-paste changelog into each function's covering comment?

Yes, I think documenting all these helpers would be very useful.  The
lack of good commens on some of the page related existing helpers has
driven me insane sometimes.