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 D3476408627; Mon, 29 Jun 2026 12:24:31 +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=1782735872; cv=none; b=UHoLJ+KN2HnzWoPVXTcGLkk5N/c9D2ChUiqwtnnlnwcwd286n3w9PTA6UF7P/xNMR3hLaJYn+PeWMJXceLkS8AgH1dnIGMN9vysoSVOcRybMoudH45D26to+ECNJDlSjEdA/vbNvCGjpebhhOGD7mExQWcFvi7jD+pKiWyzAIqI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782735872; c=relaxed/simple; bh=tlohIfU/GkJ0Rl/MxN6Kwa79ovpFTOB5ftLX3CCYYEQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nQeiciKlRFOOjchpRO/A6w7GUIyh9twY4ZVDSz9/4RQLT4cgOtVJI/CRfNRG34XTcQpzTwPjPfgO7STstkxE/Cozg0lCsLvoZxtfEsfM2qjUuklRH5qpZX76EzbNBm2ABgEY4aFY8GlDZASKP5FbXeP9DSQhpuaKRzs0QT2/rvU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gbRlBt02; 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="gbRlBt02" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B55091F00A3A; Mon, 29 Jun 2026 12:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782735871; bh=lDqHHLYLI8SULeQcrQbbmm1Xqv4SbCojm3yMjIkoYS4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gbRlBt02eZV32vXAx1N9ysOeq0S6bwI9Ce2BPgKuRfpVZlRZdgJ+Rc9bshTzbaA/Y W14Sww3HyjEdedsUcYMcpQ9oUG/ausaLK7qwWO/ObfDuCVFHpJi681zlmHI1oY44qw JuYWfnS14KRRMRCqN6X7rVTIgwoB+b+Q7CFljrLUmX4CHXFe+lXtsfDfiR+NpSZg/6 VFAgvA186XL/RNO5OBNYDw+9qoiTSPd1SJA4VjVv6xPifTqqwKvmIhr/L00cadwwD/ Av7DzDW/ixy/Z1oRx3ExXlGkJB1de3WNQx1EoGzP7SZH1bGKaVpj5CUFZ1WpGLIrVF Z+35Yut2os7Xw== From: Lorenzo Stoakes To: Andrew Morton Cc: 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, Pedro Falcato , Rik van Riel , Harry Yoo , Jann Horn Subject: [PATCH 12/30] mm/vma: clean up anon_vma_compatible() Date: Mon, 29 Jun 2026 13:23:23 +0100 Message-ID: <5a7a07bd2a774989849b0fea84f758059ed914df.1782735110.git.ljs@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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); } /* -- 2.54.0