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Date:   Wed, 12 Jul 2023 08:16:34 +0500
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Cc:     Muhammad Usama Anjum <usama.anjum@collabora.com>,
        Peter Xu <peterx@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
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        Mike Rapoport <rppt@kernel.org>, Nadav Amit <namit@vmware.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Shuah Khan <shuah@kernel.org>,
        Christian Brauner <brauner@kernel.org>,
        Yang Shi <shy828301@gmail.com>,
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        Matthew Wilcox <willy@infradead.org>,
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        Axel Rasmussen <axelrasmussen@google.com>,
        "Gustavo A . R . Silva" <gustavoars@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
        Greg KH <gregkh@linuxfoundation.org>, kernel@collabora.com
Subject: Re: [PATCH v24 2/5] fs/proc/task_mmu: Implement IOCTL to get and
 optionally clear info about PTEs
To:     Andrei Vagin <avagin@gmail.com>
References: <20230711125241.1587820-1-usama.anjum@collabora.com>
 <20230711125241.1587820-3-usama.anjum@collabora.com>
 <CANaxB-zvYpKw-aeF8nd_spARdkV29H7ZJDDhusnmqOPZX1xXtw@mail.gmail.com>
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From:   Muhammad Usama Anjum <usama.anjum@collabora.com>
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On 7/12/23 12:42 AM, Andrei Vagin wrote:
> 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?
It seems I've missed the filtering part for holes. It got missed and no
test/reviewer caught it earlier. I'll add it pretty quickly.

Are you satisfied with the remaining patch and can you sent reviewed/acked
by tag?

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

-- 
BR,
Muhammad Usama Anjum