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

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