On Mon 17-10-16 13:40:41, Ross Zwisler wrote:
> On Tue, Sep 27, 2016 at 06:08:15PM +0200, Jan Kara wrote:
> > We don't check whether vma->vm_ops is NULL in do_shared_fault() so
> > there's hardly any point in checking it in wp_page_shared() which gets
> > called only for shared file mappings as well.
> >
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > mm/memory.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/mm/memory.c b/mm/memory.c
> > index a4522e8999b2..63d9c1a54caf 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -2301,7 +2301,7 @@ static int wp_page_shared(struct vm_fault *vmf, struct page *old_page)
> >
> > get_page(old_page);
> >
> > - if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
> > + if (vma->vm_ops->page_mkwrite) {
> > int tmp;
> >
> > pte_unmap_unlock(vmf->pte, vmf->ptl);
> > --
> > 2.6.6
>
> Does this apply equally to the check in wp_pfn_shared()? Both
> wp_page_shared() and wp_pfn_shared() are called for shared file mappings via
> do_wp_page().
Yes, it does apply there as well. Added to the commit. There are actually
more places with these checks which don't seem necessary but I didn't want
to do more cleanups than I need... But at least these two come logically
together.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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