Messages in this thread | | | Date | Tue, 20 Dec 2011 15:14:37 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm: hugetlb: fix pgoff computation when unmapping page from vma |
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[CCing Mel]
On Tue 20-12-11 21:45:51, Hillf Danton wrote: > The computation for pgoff is incorrect, at least with > > (vma->vm_pgoff >> PAGE_SHIFT) > > involved. It is fixed with the available method if HPAGE_SIZE is concerned in > page cache lookup.
Have you seen this as a real issue? I guess nobody noticed as it is quite rare error case. Anyways, yes, looks good.
> Cc: Michal Hocko <mhocko@suse.cz> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
> --- > > --- a/mm/hugetlb.c Tue Dec 20 21:26:30 2011 > +++ b/mm/hugetlb.c Tue Dec 20 21:40:44 2011 > @@ -2315,8 +2315,7 @@ static int unmap_ref_private(struct mm_s > * from page cache lookup which is in HPAGE_SIZE units. > */ > address = address & huge_page_mask(h); > - pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) > - + (vma->vm_pgoff >> PAGE_SHIFT); > + pgoff = linear_hugepage_index(vma, address);
You have hstate so you can use vma_hugecache_offset directly
> mapping = (struct address_space *)page_private(page); > > /* >
Thanks -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic
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