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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7353C88E72 for ; Mon, 14 Sep 2026 22:12:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E5DBD10F2C3; Mon, 14 Sep 2026 22:12:45 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="Sqjj6lfp"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id F3C9A10F2C3 for ; Mon, 14 Sep 2026 22:12:44 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 471C660252; Mon, 14 Sep 2026 22:12:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B6FB1F000FF; Mon, 14 Sep 2026 22:12:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789423964; bh=EqtoLGLw88FFajVWqs/rzfLrA2MDhzukA4NQOYCEbPk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Sqjj6lfpmaCkN65cA8V6wT0WTZLQcFj8ssq4R0nHe1hmDVny9Tzazr9pFTMtZ60YZ CjqnCNDJY8ccvXZmTbnBEYewdKAKwo8vkkas2oC6SHLofxyHSh4OimaaTzcKfaS0TM M+NSy6lZ7gmVxIf3nPnqEm8mMXPsYOm/qnpoK+pjsvnfGsj1iiTyC23HIUnaQL4JNy O39UoN2Sd8O9+rH2pSexkE8trmIzWnl4LhVR4qbYCFcQI5k8LaaqoWZskpFGe12Poc Yk/1bWvV6dF7T2cPz7BBeAZWmtSWqtqAbkg6PE18Z1Q5kzNjRoICBrblv5IwQ21o0I B7WRBSQd9W6Vg== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 31/40] mm/vma: introduce vma[_flags]_is_persistent() To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: linux-rdma@vger.kernel.org, "Heiko Carstens" , linux-trace-kernel@vger.kernel.org, "Oliver Upton" , linux-perf-users@vger.kernel.org, kvmarm@lists.linux.dev, selinux@vger.kernel.org, "Alexander Gordeev" , kvm@vger.kernel.org, linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, "Vasily Gorbik" , dri-devel@lists.freedesktop.org, "Christian Borntraeger" , bpf@vger.kernel.org, "Marc Zyngier" In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-31-7d9781ed5361@kernel.org> References: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org> <20260914-b4-mmap-prepare-vma-flag-sanify-v2-31-7d9781ed5361@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 14 Sep 2026 22:12:42 +0000 Message-Id: <20260914221243.2B6FB1F000FF@smtp.kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" > Introduce vma[_flags]_is_persistent() for the purposes of identifying > mappings that are persistent in the sense that bytes to the mapping stay > there, and bytes read from the mapping are the same unless changed by > actions taken by userland. >=20 > Kernel-owned mappings do not fall into this category, as their owner may > change the contents without the user having initiated it, and nor of cour= se > does memory-mapped I/O. >=20 > We exclude fixed mappings as these are singled out as being unmergeable a= nd > so cannot be guaranteed to persist user data. >=20 > hugetlb mappings are fixed mappings, but their contents are entirely the > user's, so they are explicitly carved out as persistent, as the MADV_DODU= MP > check already does. >=20 > It excludes droppable mappings, which by their nature are ephemeral. >=20 > Use this functionality to update the madvise MADV_DODUMP check to test for > persistence rather than open-coding this. >=20 > This replaces the VM_SPECIAL check which means it no longer checks for > VMA_IO_BIT, however this is safe as we have established the invariant that > only kernel-owned mappings may set VMA_IO_BIT, so we implicitly include > these. >=20 > No functional change intended. >=20 > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260914-b4-mmap-pr= epare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org?part=3D31