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 1C154C43458 for ; Wed, 1 Jul 2026 10:20:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 63F3210E36A; Wed, 1 Jul 2026 10:20:26 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="cuGMmNGU"; 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 8217210E36A; Wed, 1 Jul 2026 10:20:24 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 69CE6601DE; Wed, 1 Jul 2026 10:20:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB7771F000E9; Wed, 1 Jul 2026 10:20:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782901223; bh=D5+bWR29OngXVj5rwG1+zYSN1WwMk4/7ECM6WfNh2uI=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=cuGMmNGU7E65Dg68eYFJaoaIWAAXeqkJUg8FZQJgjFh+i1j9q01MpEqRw5mq7z2rO rkXRZR9NGSQ9sII7fZOwfSIwzleA8JRMW111/zeCE0qmHsxiY/HLQ0Dm8xGge55Nbo /rPxBfTmGORtHvvZPyK97uPKTZnGWvFXgU7p2RkSdlG4PEyzwi19N3lXnrYxEkZX5b zl9UvB9/CJ8gR1giihtd/aBTGzdpN/Ulj4oApN/i9Aqbvc2Mp6sFjuGNqa0yzOHDgG nR1WDpWllVqYqSGN3pkdhjkgYYrs6JaUJqiQNQpkXzrrwNWf/Am7VMbc8hwnba0Luf /Q1TqhzeWdoGA== Date: Wed, 1 Jul 2026 11:20:01 +0100 From: Lorenzo Stoakes To: Pedro Falcato Cc: Andrew Morton , Russell King , Dinh Nguyen , Simon Schuster , "James E . J . Bottomley" , Helge Deller , Jarkko Sakkinen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Ian Abbott , H Hartley Sweeten , Lucas Stach , David Airlie , Simona Vetter , Patrik Jakobsson , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , Dmitry Baryshkov , Tomi Valkeinen , Thierry Reding , Mikko Perttunen , Jonathan Hunter , Christian Koenig , Huang Rui , Ankit Agrawal , Alex Williamson , Alexander Viro , Christian Brauner , Dan Williams , Muchun Song , Oscar Salvador , David Hildenbrand , Suren Baghdasaryan , "Liam R . Howlett" , Matthew Wilcox , Marek Szyprowski , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Masami Hiramatsu , Oleg Nesterov , Steven Rostedt , SeongJae Park , Miaohe Lin , Hugh Dickins , Mike Rapoport , Kees Cook , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, linux-sgx@vger.kernel.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-tegra@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org, iommu@lists.linux.dev, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kasan-dev@googlegroups.com, damon@lists.linux.dev, Rik van Riel , Harry Yoo , Jann Horn Subject: Re: [PATCH 12/30] mm/vma: clean up anon_vma_compatible() Message-ID: References: <5a7a07bd2a774989849b0fea84f758059ed914df.1782735110.git.ljs@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Jun 30, 2026 at 05:36:18PM +0100, Pedro Falcato wrote: > On Mon, Jun 29, 2026 at 01:23:23PM +0100, Lorenzo Stoakes wrote: > > Break up the existing very large conditional, add comments and use > > vma_[start/end]_pgoff() to make clearer what we're doing here. > > > > No functional change intended. > > > > Signed-off-by: Lorenzo Stoakes > > --- > > mm/vma.c | 21 ++++++++++++++++----- > > 1 file changed, 16 insertions(+), 5 deletions(-) > > > > diff --git a/mm/vma.c b/mm/vma.c > > index b60375c6c5c3..6296acecf3b7 100644 > > --- a/mm/vma.c > > +++ b/mm/vma.c > > @@ -1967,14 +1967,25 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct * > > { > > vma_flags_t diff = vma_flags_diff_pair(&a->flags, &b->flags); > > > > + /* Ignore flags that mprotect() can change. */ > > vma_flags_clear_mask(&diff, VMA_ACCESS_FLAGS); > > + /* Ignore flags that do not impact merging. */ > > vma_flags_clear_mask(&diff, VMA_IGNORE_MERGE_FLAGS); > > > > - return a->vm_end == b->vm_start && > > - mpol_equal(vma_policy(a), vma_policy(b)) && > > - a->vm_file == b->vm_file && > > - vma_flags_empty(&diff) && > > - b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); > > + /* Must be adjacent. */ > > + if (a->vm_end != b->vm_start) > > + return false; > > + /* Must have matching policy. */ > > + if (!mpol_equal(vma_policy(a), vma_policy(b))) > > + return false; > > + /* Must both be anon or map the same file (MAP_PRIVATE case). */ > > + if (a->vm_file != b->vm_file) > > + return false; > > + /* Flags must be equivalent modulo mprotect(). */ > > + if (!vma_flags_empty(&diff)) > > + return false; > > + /* Page offset must align. */ > > + return vma_end_pgoff(a) == vma_start_pgoff(b); > > Very nice. > > Reviewed-by: Pedro Falcato Thanks :) > > -- > Pedro Cheers, Lorenzo