[PATCH v2 hmm 7/9] mm/hmm: do not unconditionally set pfns when returning EBUSY

[Christoph Hellwig]

On Mon, Mar 23, 2020 at 10:14:55PM -0300, Jason Gunthorpe wrote:
>  	if (pte_none(pte)) {
>  		required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0);
>  		if (required_fault)
>  			goto fault;
> +		*pfn = range->values[HMM_PFN_NONE];
>  		return 0;
>  	}
>  
> @@ -274,8 +274,10 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
>  		}
>  
>  		required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0);
> -		if (!required_fault)
> +		if (!required_fault) {
> +			*pfn = range->values[HMM_PFN_NONE];
>  			return 0;
> +		}

Maybe throw in a goto hole to consolidaste the set PFN and return
0 cases?

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch at lst.de>