Re: [PATCH v2 2/3] mm: Allow architectures to request 'old' entries when prefaulting

[Kirill A. Shutemov]

On Fri, Jan 08, 2021 at 05:15:16PM +0000, Will Deacon wrote:
> diff --git a/mm/filemap.c b/mm/filemap.c
> index c1f2dc89b8a7..0fb9d1714797 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -3051,14 +3051,18 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
>  		if (!pte_none(*vmf->pte))
>  			goto unlock;
>  
> +		/* We're about to handle the fault */
> +		if (vmf->address == address) {
> +			vmf->flags &= ~FAULT_FLAG_PREFAULT;
> +			ret = VM_FAULT_NOPAGE;
> +		} else {
> +			vmf->flags |= FAULT_FLAG_PREFAULT;
> +		}
> +

Do we need to restore the oririnal status of the bit once we are done?

-- 
 Kirill A. Shutemov