linux-kernel - Re: [PATCH v2 2/5] userfaultfd, shmem: use a VMA callback to handle UFFDIO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ab2044e8-5d9e-4ccb-b430-dcfdd5e32e3a@kernel.org>
Date: Wed, 26 Nov 2025 11:21:26 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: Mike Rapoport <rppt@...nel.org>, linux-mm@...ck.org
Cc: Andrea Arcangeli <aarcange@...hat.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Axel Rasmussen <axelrasmussen@...gle.com>,
 Baolin Wang <baolin.wang@...ux.alibaba.com>, Hugh Dickins
 <hughd@...gle.com>, James Houghton <jthoughton@...gle.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, Michal Hocko
 <mhocko@...e.com>, Nikita Kalyazin <kalyazin@...zon.com>,
 Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
 Sean Christopherson <seanjc@...gle.com>, Shuah Khan <shuah@...nel.org>,
 Suren Baghdasaryan <surenb@...gle.com>, Vlastimil Babka <vbabka@...e.cz>,
 linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
 linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 2/5] userfaultfd, shmem: use a VMA callback to handle
 UFFDIO_CONTINUE

On 11/25/25 19:38, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>
> 
> When userspace resolves a page fault in a shmem VMA with UFFDIO_CONTINUE
> it needs to get a folio that already exists in the pagecache backing
> that VMA.
> 
> Instead of using shmem_get_folio() for that, add a get_folio() method to
> 'struct vm_operations_struct' that will return a folio if it exists in
> the VMA's pagecache at given pgoff.
> 
> Implement get_folio() method for shmem and slightly refactor
> userfaultfd's mfill_atomic() and mfill_atomic_pte_continue() to support
> this new API.
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
> ---

Acked-by: David Hildenbrand (Red Hat) <david@...nel.org>

-- 
Cheers

David