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Message-ID: <CABb0KFGhSLAHAsa3nk-pyMe2j9MU4u3xkQR21HOoS65ZB2dKsw@mail.gmail.com>
Date: Wed, 21 Jun 2023 15:42:20 +0200
From: Michał Mirosław <emmir@...gle.com>
To: Muhammad Usama Anjum <usama.anjum@...labora.com>
Cc: Peter Xu <peterx@...hat.com>, David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Andrei Vagin <avagin@...il.com>,
Danylo Mocherniuk <mdanylo@...gle.com>,
Paul Gofman <pgofman@...eweavers.com>,
Cyrill Gorcunov <gorcunov@...il.com>,
Mike Rapoport <rppt@...nel.org>, Nadav Amit <namit@...are.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Shuah Khan <shuah@...nel.org>,
Christian Brauner <brauner@...nel.org>,
Yang Shi <shy828301@...il.com>,
Vlastimil Babka <vbabka@...e.cz>,
"Liam R . Howlett" <Liam.Howlett@...cle.com>,
Yun Zhou <yun.zhou@...driver.com>,
Suren Baghdasaryan <surenb@...gle.com>,
Alex Sierra <alex.sierra@....com>,
Matthew Wilcox <willy@...radead.org>,
Pasha Tatashin <pasha.tatashin@...een.com>,
Axel Rasmussen <axelrasmussen@...gle.com>,
"Gustavo A . R . Silva" <gustavoars@...nel.org>,
Dan Williams <dan.j.williams@...el.com>,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
Greg KH <gregkh@...uxfoundation.org>, kernel@...labora.com
Subject: Re: [PATCH v20 2/5] fs/proc/task_mmu: Implement IOCTL to get and
optionally clear info about PTEs
On Wed, 21 Jun 2023 at 09:24, Muhammad Usama Anjum
<usama.anjum@...labora.com> wrote:
[...]
> +static int pagemap_scan_test_walk(unsigned long start, unsigned long end,
> + struct mm_walk *walk)
> +{
> + struct pagemap_scan_private *p = walk->private;
> + struct vm_area_struct *vma = walk->vma;
> +
> + if ((p->flags & PM_SCAN_REQUIRE_UFFD) && (!userfaultfd_wp_async(vma) ||
> + !userfaultfd_wp_use_markers(vma)))
> + return -EPERM;
> +
> + if (vma->vm_flags & VM_PFNMAP)
> + return 1;
> +
> + return 0;
> +}
This could actually short-circuit all vma flags (e.g. IS_FILE): if
(required_mask & IS_FILE && vma is not file-backed) return 0;
Best Regards
Michał Mirosław
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