From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80EFC40801E; Wed, 1 Jul 2026 10:20:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901224; cv=none; b=k5UpckVfxLuvjJanlA3/jxEg+4Jmyj1n1VcAjDYgswqwnVnEDjMlCb8E0Nw1fCl8cBTEWzpvH+Qc74qNwImSFVhZ6PwJiTzU030h9KwHaK2J3GjEXGDLlcDKBuued859wbhPRIOpqppo06z9FW6xKY9VH32m7iJxwx8+GIpMBWg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901224; c=relaxed/simple; bh=101zV9Ua8MrulHr52ErsPaWpqloDAxtIiKCTYSX1KW8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dCHw5Ws+6S7uzW5Dx8V0B7AkkaqIUxzo3ID3Tyc3L0fP1amjClXjvhWSPGi1NP01c8NLTgmCt07TbqusOiADMfYtANB5HQkL1G1OhkweuwyTik9/spoeh+oUcgFd1ZS/7QVuObNE3QAsmiknO0cYxZBPvvGUdc6ISjz7iv7EOoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cuGMmNGU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cuGMmNGU" 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> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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