Re: [RFC PATCH v2 12/47] hugetlb: add hugetlb_hgm_walk and hugetlb_walk_step

[Jane Chu]

> + * @stop_at_none determines what we do when we encounter an empty PTE. If true,
> + * we return that PTE. If false and @sz is less than the current PTE's size,
> + * we make that PTE point to the next level down, going until @sz is the same
> + * as our current PTE.
[..]
> +int hugetlb_hgm_walk(struct mm_struct *mm, struct vm_area_struct *vma,
> +		     struct hugetlb_pte *hpte, unsigned long addr,
> +		     unsigned long sz, bool stop_at_none)
> +{
[..]
> +	while (hugetlb_pte_size(hpte) > sz && !ret) {
> +		pte = huge_ptep_get(hpte->ptep);
> +		if (!pte_present(pte)) {
> +			if (stop_at_none)
> +				return 0;
> +			if (unlikely(!huge_pte_none(pte)))
> +				return -EEXIST;

If 'stop_at_none' means settling down on the just encountered empty PTE,
should the above two "if" clauses switch order?  I thought Peter has
raised this question too, but I'm not seeing a response.

Regards,
-jane


> +		} else if (hugetlb_pte_present_leaf(hpte, pte))
> +			return 0;
> +		ret = hugetlb_walk_step(mm, hpte, addr, sz);
> +	}
> +
> +	return ret;
> +}
> +