[PATCH hmm 9/8] mm/hmm: do not check pmd_protnone twice in hmm_vma_handle_pmd()

[Ralph Campbell]

On 3/12/20 12:33 PM, Jason Gunthorpe wrote:
> pmd_to_hmm_pfn_flags() already checks it and makes the cpu flags 0. If no
> fault is requested then the pfns should be returned with the not valid
> flags.
> 
> It should not unconditionally fault if faulting is not requested.
> 
> Fixes: 2aee09d8c116 ("mm/hmm: change hmm_vma_fault() to allow write fault on page basis")
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>

Looks good to me.
Reviewed-by: Ralph Campbell <rcampbell at nvidia.com>

> ---
>   mm/hmm.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Bonus patch, this one got found after I made the series..
> 
> diff --git a/mm/hmm.c b/mm/hmm.c
> index ca33d086bdc190..6d9da4b0f0a9f8 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -226,7 +226,7 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
>   	hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags,
>   			     &fault, &write_fault);
>   
> -	if (pmd_protnone(pmd) || fault || write_fault)
> +	if (fault || write_fault)
>   		return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk);
>   
>   	pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
>