From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 16F19E63F08 for ; Sun, 15 Feb 2026 17:48:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C2CDB6B0088; Sun, 15 Feb 2026 12:47:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C05756B0089; Sun, 15 Feb 2026 12:47:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B3A8E6B008A; Sun, 15 Feb 2026 12:47:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 8EF6C6B0088 for ; Sun, 15 Feb 2026 12:47:49 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 20F22C2061 for ; Sun, 15 Feb 2026 17:47:33 +0000 (UTC) X-FDA: 84447423186.29.6AB7617 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf17.hostedemail.com (Postfix) with ESMTP id 87F6440003 for ; Sun, 15 Feb 2026 17:47:31 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=fbrYBjCS; spf=pass (imf17.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1771177651; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=QYNqRb5/SExj93Wn0ufGj8S+4ofEOfqonLngGkSFFRo=; b=abmMwvCZrJu0VWCbAgYteBbCRt+ErJ5j/cHrLw+HIorZ1mK35gbYUcbiSKRtC9G83RSFXS uKi1BWR7tHIlawDyidOBilngOru7RyT6RvOxKDvDVEQXGIZpGKyCwEpQNldWFw2Q04O+77 NUSFq8ytF9Hm5dDF7aaZLaN1Hmyq/hA= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=fbrYBjCS; spf=pass (imf17.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1771177651; a=rsa-sha256; cv=none; b=dNs/mWExeaekBiA5Ak5sCzucGeYEF0jz2oPkjzYBo19Ot5IjLi06VP4X4CUChWCCFMoVo2 evmwxy+F0rLrWNAm4L5x8daAG/Dlje1c6Sm1o5G7ZLZl7EJRUE26vjX0e9jDPaMc2/2jTF 6UGSwGlr8AgWyOaS325sYshXYG4OjRA= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id A1FB560008; Sun, 15 Feb 2026 17:47:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54B06C4CEF7; Sun, 15 Feb 2026 17:47:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771177650; bh=WauyYvE1fxZu8CMoxtW1HF3J+YpjZ/sOClCwhExhX3w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fbrYBjCS7QUw/rE+JE8LWK3tTpdARCB19ZpCOzFQFJYGvUsGOHm6o4hP+P7BDXHS6 1Ra7umuePXGYH6F/+80Rm0n5TmkfK14mAyS9ntBXHkWecssXL0KP48r5LlHdNKCB/v Yikkfr4c84VgkViQbjDlEPjtnJr8q/+vckh4k7MX3co2ZRshjaZYmP5lR8kUhoF2lk XG9vwuHdbwOddDuJB7oSLZ4+XvlH5VSCO7CBJdBL+lBg3Wv8xOtfQ/eBwGNFheDjU/ Eituud2nlH0GtfZ47cgpkILBkjYqEq3d7GDUZKTTTqcgd7VR2xlMlt0CBgwzA5r05Z SFgCDu9R+kG4Q== Date: Sun, 15 Feb 2026 19:47:19 +0200 From: Mike Rapoport To: Peter Xu Cc: linux-mm@kvack.org, Andrea Arcangeli , Andrew Morton , Axel Rasmussen , Baolin Wang , David Hildenbrand , Hugh Dickins , James Houghton , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH RFC 07/17] userfaultfd: introduce vm_uffd_ops Message-ID: References: <20260127192936.1250096-1-rppt@kernel.org> <20260127192936.1250096-8-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 87F6440003 X-Stat-Signature: s43cnrkfaipxtooj36ohxw9x769hehtt X-Rspam-User: X-HE-Tag: 1771177651-462314 X-HE-Meta: U2FsdGVkX1+dII2/92rbUcFBJWaHzpcb5iX4mUF4mOhRwW4LsiRn9Uhnfup10xqGHTdrp+rGVEu8G0jfUA866vgQj5DaRhUrQsk8nBb87Cpx80s5Kun0U8p6eN9iMKKOBVLDRILgVs7/XxBui1Rz/mBqGiC4olam42FhiDtGn2OxBCDSMKPnxuQ/P09U5VH5dtFsbo/KLTz5YRBFHW6PRQXGgBxB8YqEaiuLxZXSbjj0mDsy9FXnm/CBGtL/dUVXEWEi7TCUEh6PBmz5Om4+XIx4HI0g3wrdFikfaWyHHq5kSp47MP+gQYOB2+BnVlVc8qkb3CUP5Jkx+YVNZuEfGyG0FfFKJvnzqSoDBaeGRCkOGiPHKD8/+xw/BauDmplFt7SYdZ3fSyMsdqhmXaVN++Dvhy5H3sQ4hYFo4IHwVjDAQ4K0651NKMSKOJpZOE7mSSuafExsAfZ18NAQnVi0TiORBggMbPq1dyvtpzaWSM9BkCS4SPNbRcO1r28w5A1yGJfzM6t5mKTjA6kv/jOPp9v0iolIwfLfShvi0q34C75k9oqSW0jUvkz+hjAJc5ARYM6+m3NgvFSmXjjLQk1A6kocAyIJ5AY5cizBOkq0ilGmakEIGE0iVnv+Z5cOMDBl/a6lz9WeR3AwY32Arg/s+EMnqAWRLf+FIH59IzXUU3IdBaPShxv+G5qeadP7QvXEwt5GwGUTospqSAwsglVVBhSXV9iLEsiVgT+QMWwnCJywElSEW19cqsd7wGg0i/9I0ntf3YbgRVnVnuk9J+Msot4OK5dwzahGz5s4AEcwEf4IrOe1ZMSSEeQH/J+oXRl179jj+D9bjuITLTnaCZuArC2DOvAvlzHEZAIZhilQWQB50saIRAiuwCsxgyxP9bJ0gl50ge1uvVu1AM84wJ6HDhYSg2QQOKckVo0cA+SbNqtbSJ/3BTVXPGtiZsDNuGhxWSVZKoY2b4r8miCZAKg 1yd9wIZ5 W9FfFac1EVrj91bgEsNaALoHsPlO5IqwOWiihZHSKJ83xIpodRGqGbU32FLPQ93nE3mXpFNiPg7mOQ6BaifoqLD7ApECkgsFebjzJa76azrTrS88K4D8LgB2F3o0PMs6Gl6QFkMZeFmw0tVv814ksf9J6xsdrYGksKMzJJIFde3kocb7E54JcknwY9hSgvkZW7FR31oClFw6yowDIyVVwUzDySu4bV0QsYPoWDjgTJty5HsKJJZSt/RyyaoRieHTgad2qIyM7BoLg8gZi8Vjgkw9csDmZ9zIv+WYBl5jeqzL5DxY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Feb 11, 2026 at 02:35:23PM -0500, Peter Xu wrote: > On Sun, Feb 08, 2026 at 12:13:45PM +0200, Mike Rapoport wrote: > > > > > > I understand you wanted to also make anon to be a driver, so this line > > > won't apply to anon. However IMHO anon is special enough so we can still > > > make this in the generic path. > > > > Well, the idea is to drop all vma_is*() in can_userfault(). And maybe > > eventually in entire mm/userfaultfd.c > > > > If all page cache filesystems need this, something like this should work, > > right? > > > > if (!uffd_supports_wp_marker() && (vma->vm_flags & VM_SHARED) && > > (vm_flags & VM_UFFD_WP)) > > return false; > > Sorry for a late response. > > IMHO using vma_is_anonymous() for one more time should be better than > leaking pte marker whole concept to modules. So the driver should only > report if the driver supports UFFD_WP in general. It shouldn't care about > anything the core mm would already do otherwise, including this one on > "whether system config / arch has globally enabled pte markers" and the > relation between that config and the WP feature impl details. I agree. Will move the check for the markers back into userfaultfd.c > Thanks, > > -- > Peter Xu > -- Sincerely yours, Mike.