Re: [PATCH v4 1/2] block: add folio awareness instead of looping through pages

[Christoph Hellwig <hch@lst.de>]

On Wed, Jun 05, 2024 at 07:45:23PM +0100, Matthew Wilcox wrote:
> >  	if (bio->bi_vcnt > 0 &&
> >  	    bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],
> > -				page, len, offset, &same_page)) {
> > +				&folio->page, len, offset, &same_page)) {
> 
> Let's make that folio_page(folio, 0)

Or just pass a folio to bvec_try_merge_page (and rename it) if we want
to go all the way, but given that that will go down quite a bit
into xen and zone device code maybe that's not worth it for now as
we should eventually just convert it to a plain phys_addr_t anyway.

> >  	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
> >  	bool same_page = false;
> >  
> > -	if (bio_add_hw_page(q, bio, page, len, offset,
> > +	if (bio_add_hw_page(q, bio, &folio->page, len, offset,
> 
> Likewise.

OTOH replacing / augmenting bio_add_hw_page with a bio_add_hw_folio
should be worthwhile, so I'd love to see that as a prep patch.