Re: [PATCH] block: Remove special-casing of compound pages

On Mon, Aug 14, 2023 at 03:41:00PM +0100, Matthew Wilcox (Oracle) wrote:

void __bio_release_pages(struct bio *bio, bool mark_dirty) {

• struct bvec_iter_all iter_all;
• struct bio_vec *bvec;

• struct folio_iter fi;
• bio_for_each_folio_all(fi, bio) {

• struct page *page;
  

• size_t done = 0;
  

• bio_for_each_segment_all(bvec, bio, iter_all) {

• if (mark_dirty && !PageCompound(bvec->bv_page))
  

• 	set_page_dirty_lock(bvec->bv_page);
  

• bio_release_page(bio, bvec->bv_page);
  

• if (mark_dirty) {
  

• 	folio_lock(fi.folio);
  

• 	folio_mark_dirty(fi.folio);
  

• 	folio_unlock(fi.folio);
  

• }
  

• page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
  

• do {
  

• 	bio_release_page(bio, page++);
  

• 	done += PAGE_SIZE;
  

• } while (done < fi.length);
  

  }

}

Is it okay to release same-folio pages while creating the bio instead of releasing all the pages at the completion? If so, the completion could provide just the final bio_release_page() instead looping. I'm more confirming if that's an appropriate way to use folios here.