Re: [PATCH 1/6] mm/page_io: use a folio in __end_swap_bio_read()

[zhangpeng (AS)]

On 2023/7/17 21:34, Matthew Wilcox wrote:

> On Mon, Jul 17, 2023 at 09:25:57PM +0800, Peng Zhang wrote:
> > +++ b/mm/page_io.c
> > @@ -58,18 +58,18 @@ static void end_swap_bio_write(struct bio *bio)
> >   
> >   static void __end_swap_bio_read(struct bio *bio)
> >   {
> > -	struct page *page = bio_first_page_all(bio);
> > +	struct folio *folio = page_folio(bio_first_page_all(bio));
> Should we have a bio_first_folio_all()?  It wouldn't save any calls to
> compound_head(), but it's slightly easier to use.

Yes, I'll convert bio_first_page_all() to bio_first_folio_all() in a v2.
Thanks.

> >   	if (bio->bi_status) {
> > -		SetPageError(page);
> > -		ClearPageUptodate(page);
> > +		folio_set_error(folio);
> I appreciate this is a 1:1 conversion, but maybe we could think about
> this a bit.  Is there anybody who checks the
> PageError()/folio_test_error() for this page/folio?

Maybe wait_dev_supers() checks the PageError() after write_dev_supers()
in fs/btrfs/disk-io.c?

> > +		folio_clear_uptodate(folio);
> Similarly ... surely the folio is already !uptodate, so we don't need to
> clear the flag?

Indeed, the folio is already !uptodate. I'll drop this line in a v2.
Thanks for your feedback.

--
Best Regards,
Peng