On Thu, Apr 04, 2019 at 05:28:02PM -0400, Qian Cai wrote:
> On Thu, 2019-04-04 at 16:45 +0300, Kirill A. Shutemov wrote:
> > What about this:
> >
> > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> > index f939e004c5d1..2e8438a1216a 100644
> > --- a/include/linux/pagemap.h
> > +++ b/include/linux/pagemap.h
> > @@ -335,12 +335,15 @@ static inline struct page *grab_cache_page_nowait(struct
> > address_space *mapping,
> >
> > static inline struct page *find_subpage(struct page *page, pgoff_t offset)
> > {
> > - unsigned long index = page_index(page);
> > + unsigned long mask;
> > +
> > + if (PageHuge(page))
> > + return page;
> >
> > VM_BUG_ON_PAGE(PageTail(page), page);
> > - VM_BUG_ON_PAGE(index > offset, page);
> > - VM_BUG_ON_PAGE(index + (1 << compound_order(page)) <= offset, page);
> > - return page - index + offset;
> > +
> > + mask = (1UL << compound_order(page)) - 1;
> > + return page + (offset & mask);
> > }
> >
> > struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
>
> It works fine.
Nice.
Matthew, does it look fine to you?
--
Kirill A. Shutemov
