Re: [PATCH v4 1/6] userfaultfd: convert mfill_atomic_pte_copy() to use a folio

[Matthew Wilcox]

On Thu, Mar 30, 2023 at 10:02:52AM -0700, Sidhartha Kumar wrote:
> On 3/30/23 6:40 AM, Peng Zhang wrote:
> > From: ZhangPeng <zhangpeng362@xxxxxxxxxx>
> > 
> > Call vma_alloc_folio() directly instead of alloc_page_vma(). Add an
> > assertion that this is a single-page folio and removes several calls to
> > compound_head().

There's no added assertion in this patch any more, so I'd drop that
part of the description.

> >   	if (!*pagep) {
> >   		ret = -ENOMEM;
> > -		page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, dst_vma, dst_addr);
> > -		if (!page)
> > +		folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, dst_vma, dst_addr, false);
> > +		if (!folio)
> >   			goto out;
> > -		page_kaddr = kmap_local_page(page);
> > +		page_kaddr = kmap_local_folio(folio, 0);
> 
> Should this variable name be kept as page_kaddr or should it be changed to
> something like folio_kaddr? kmap_local_folio() returns page_address(), so
> maybe page_kaddr is better.

I'd just call it 'kaddr'.  Or 'addr'.