Re: [PATCH 4/5] mm/vma: Replace all remaining open encodings with vma_set_anonymous()

[Kirill A. Shutemov]

On Mon, Feb 17, 2020 at 10:33:52AM +0530, Anshuman Khandual wrote:
> This replaces all remaining open encodings with vma_set_anonymous().
> 
> Cc: Sudeep Dutt <sudeep.dutt@xxxxxxxxx>
> Cc: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
> Cc: Allison Randal <allison@xxxxxxxxxxx>
> Cc: Richard Fontana <rfontana@xxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
>  drivers/misc/mic/scif/scif_mmap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/mic/scif/scif_mmap.c b/drivers/misc/mic/scif/scif_mmap.c
> index a151d416f39c..1f0dec5df994 100644
> --- a/drivers/misc/mic/scif/scif_mmap.c
> +++ b/drivers/misc/mic/scif/scif_mmap.c
> @@ -580,7 +580,7 @@ static void scif_munmap(struct vm_area_struct *vma)
>  	 * The kernel probably zeroes these out but we still want
>  	 * to clean up our own mess just in case.
>  	 */
> -	vma->vm_ops = NULL;
> +	vma_set_anonymous(vma);
>  	vma->vm_private_data = NULL;
>  	kref_put(&vmapvt->ref, vma_pvt_release);
>  	scif_delete_vma(ep, vma);

This is misleading. The VMA doesn't become anonymous here. This is undo of
the previously overwritten vm_ops. I think we should leave it opencodded.

-- 
 Kirill A. Shutemov