On Mon, Jan 11, 2021 at 05:25:33PM +0300, Kirill A. Shutemov wrote:
> On Fri, Jan 08, 2021 at 05:15:16PM +0000, Will Deacon wrote:
> > diff --git a/mm/filemap.c b/mm/filemap.c
> > index c1f2dc89b8a7..0fb9d1714797 100644
> > --- a/mm/filemap.c
> > +++ b/mm/filemap.c
> > @@ -3051,14 +3051,18 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
> > if (!pte_none(*vmf->pte))
> > goto unlock;
> >
> > + /* We're about to handle the fault */
> > + if (vmf->address == address) {
> > + vmf->flags &= ~FAULT_FLAG_PREFAULT;
> > + ret = VM_FAULT_NOPAGE;
> > + } else {
> > + vmf->flags |= FAULT_FLAG_PREFAULT;
> > + }
> > +
>
> Do we need to restore the oririnal status of the bit once we are done?
I can certainly add that, although it doesn't look like we do that for
vmf->pte, so it's hard to tell what the rules are here. It certainly feels
odd to restore some fields but not others, as it looks like vmf->address
will be out-of-whack with vmf->pte when filemap_map_pages() returns. Am I
missing something?
Will
