On Wed, Nov 03, 2021 at 09:00:57AM -0700, Darrick J. Wong wrote: > > - wpc->ops->discard_folio(page_folio(page), file_offset); > > + wpc->ops->discard_folio(folio, pos); > > /me wonders why this wouldn't have been done in whichever patch added > folio as a local variable, but fmeh, the end result is the same: Found it and fixed it. > > @@ -1474,17 +1474,15 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data) > > * memory is zeroed when mapped, and writes to that region are > > * not written out to the file." > > */ > > - zero_user_segment(page, poff, PAGE_SIZE); > > - > > - /* Adjust the end_offset to the end of file */ > > + zero_user_segment(&folio->page, poff, folio_size(folio)); > > Question: is &folio->page != page here? I guess the idea is that we > have a (potentially multi-page) folio straddling i_size, and we need to > zero everything in the whole folio after i_size. But then why not pass > the whole folio? Ugh, thanks. You made me realise that zero_user_segments() is still conditional on CONFIG_TRANSPARENT_HUGEPAGE. It's a relic of when I was going to do all of this with THP; before I switched to the folio mental model. So now we're going to get folio_zero_segments(), folio_zero_segment() and folio_zero_range().
