Re: [1/5] follow_page: do not put_page if FOLL_GET not specified.

Peter Zijlstra
2006-05-23T18:29:10Z

On Tue, 2006-05-23 at 10:43 -0700, Christoph Lameter wrote:
> follow: no put_page() if FOLL_GET not specified.
>
> Seems that one of the side effects of the dirty pages patch in
> 2.6.17-rc4-mm3 is that follow_pages does a page_put if FOLL_GET is
> not set in the flags passed to it. This breaks sys_move_pages()
> page status determination.
>
> Only put_page if we did a get_page() before.
>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

However, Andrew dropped the patches from -mm. I'll do a new series that
incorporates the suggestions from Hugh.

> Index: linux-2.6.17-rc4-mm3/mm/memory.c
> =================================> --- linux-2.6.17-rc4-mm3.orig/mm/memory.c 2006-05-22 18:03:32.280767264 -0700
> +++ linux-2.6.17-rc4-mm3/mm/memory.c 2006-05-23 10:01:48.917295988 -0700
> @@ -964,7 +964,7 @@ struct page *follow_page(struct vm_area_
> set_page_dirty(page);
> mark_page_accessed(page);
> }
> - if (!(flags & FOLL_GET))
> + if (!(flags & FOLL_GET) && (flags & FOLL_TOUCH))
> put_page(page);
> goto out;
>