Messages in this thread | | | Date | Mon, 9 Jul 2018 09:53:57 -0600 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/2] mm: introduce put_user_page(), placeholder version |
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On Mon, Jul 09, 2018 at 01:05:53AM -0700, john.hubbard@gmail.com wrote: > From: John Hubbard <jhubbard@nvidia.com> > > Introduces put_user_page(), which simply calls put_page(). > This provides a safe way to update all get_user_pages*() callers, > so that they call put_user_page(), instead of put_page(). > > Also adds release_user_pages(), a drop-in replacement for > release_pages(). This is intended to be easily grep-able, > for later performance improvements, since release_user_pages > is not batched like release_pages is, and is significantly > slower. > > Subsequent patches will add functionality to put_user_page(). > > Signed-off-by: John Hubbard <jhubbard@nvidia.com> > include/linux/mm.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index a0fbb9ffe380..db4a211aad79 100644 > +++ b/include/linux/mm.h > @@ -923,6 +923,20 @@ static inline void put_page(struct page *page) > __put_page(page); > } > > +/* Placeholder version, until all get_user_pages*() callers are updated. */ > +static inline void put_user_page(struct page *page) > +{ > + put_page(page); > +} > + > +/* A drop-in replacement for release_pages(): */ > +static inline void release_user_pages(struct page **pages, > + unsigned long npages) > +{ > + while (npages) > + put_user_page(pages[--npages]); > +} > + > #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) > #define SECTION_IN_PAGE_FLAGS > #endif
Just as question: Do you think it is worthwhile to have a release_user_page_dirtied() helper as well?
Ie to indicate that a pages that were grabbed under GUP FOLL_WRITE were actually written too?
Keeps more of these unimportant details out of the drivers..
Jason
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