Re: [PATCH v24 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs

[Andrei Vagin <avagin@gmail.com>]

On Tue, Jul 11, 2023 at 5:53 AM Muhammad Usama Anjum
<usama.anjum@collabora.com> wrote:

<snip>

> +static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
> +                                int depth, struct mm_walk *walk)
> +{
> +       unsigned long n_pages = (end - addr)/PAGE_SIZE;
> +       struct pagemap_scan_private *p = walk->private;
> +       struct vm_area_struct *vma = walk->vma;
> +       int ret = 0;
> +
> +       if (!vma)
> +               return 0;
> +
> +       if (IS_PM_SCAN_GET(p->flags)) {
> +               if (n_pages > p->max_pages - p->found_pages)
> +                       n_pages = p->max_pages - p->found_pages;
> +
> +               ret = pagemap_scan_output(PM_SCAN_FLAGS(false, false, false,
> +                                         false, false), p, addr, n_pages);

Why do we report holes unconditionally?

> +       }
> +
> +       if (IS_PM_SCAN_WP(p->flags) &&
> +           uffd_wp_range(vma, addr, end - addr, true) < 0)
> +               ret = -EINVAL;
> +
> +       return ret;
> +}

Thanks,
Andrei