From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D73F226159E; Mon, 23 Mar 2026 15:51:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774281115; cv=none; b=c0kZmJghE9fLDBxGytJmtgEa0/ib/u0xVnWWVQM/DfKQ6gbzlltedODadFpdiu3MrEb4004D+ljeozhA8QeXU9vxQevYavSDSAkKDicX0B3MNzMKOegfLSb/zhwu8uQh3FZPj8ONOp5ME3ArW/pUaL+4wvN8O5kLzz+4uIpCc78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774281115; c=relaxed/simple; bh=vZdm4GONA/O1jK4+M6185Q0giqh3AS1i2sFB5Pfd/2Y=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WC/Su5DSfbmKx/hjjLx/LWUbWOrLtkC+iAtlSS3Ov8uRSbFx+FSuKN5K9Y7423IO//a3uq1zVVBsKflkqLnS2RxcBs+9CJeJYk9SLvxeYLMbT8sPvlYBC/w0ZotbH2yLYJvHqZxWSXc+2/FG2D737L1EOieH3Ivfyp0uqVdkFYE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o1THjGW8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="o1THjGW8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCA5BC4CEF7; Mon, 23 Mar 2026 15:51:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774281115; bh=vZdm4GONA/O1jK4+M6185Q0giqh3AS1i2sFB5Pfd/2Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=o1THjGW87BBZn2ZRvUB/ZbG6Bpk46OGuXu9+rNxgEX1JPplRd0PmhhIVaepJQX2x+ tNfnZZ2oJ/LEW/V1kb+Kd4rSlee9+4uD+RKeGWfnc/xNRMj7aASQw2bbJQ+4aFpnT4 D5oU71wAa1icX022onJ8SXq1egN+wMrKLzs0GkJXDMxvnSocAjVWuUsitbcyyxaQfV JJXP9c4lBWKh9RLPX/Xy30cKFsVybbnBnhAp26jeybHA0vntxV0OkXb/w0rzQv6/lE VQ33MGCeDpT2FONGoMZBv7aFNGtJEznzEExGGKYXFQSBLYixZR0A4kZUSTFL4AAduW zfBJEYhpa4mqQ== Message-ID: <47f796ed-ac66-4a75-98c9-64afc8929f35@kernel.org> Date: Mon, 23 Mar 2026 16:51:41 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 25/25] mm: simplify VMA flag tests of excluded flags To: "Lorenzo Stoakes (Oracle)" , Andrew Morton Cc: David Hildenbrand , "Liam R . Howlett" , Jann Horn , Pedro Falcato , Mike Rapoport , Suren Baghdasaryan , Kees Cook , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Brian Cain , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Dinh Nguyen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Richard Weinberger , Anton Ivanov , Johannes Berg , Alexander Viro , Christian Brauner , Jan Kara , Xu Xin , Chengming Zhou , Michal Hocko , Paul Moore , Stephen Smalley , Ondrej Mosnacek , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, linux-fsdevel@vger.kernel.org, selinux@vger.kernel.org References: From: "Vlastimil Babka (SUSE)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/20/26 8:38 PM, Lorenzo Stoakes (Oracle) wrote: > We have implemented flag mask comparisons of the form: > > if ((vm_flags & (VM_FOO|VM_BAR|VM_BAZ) == VM_FOO) { ... } > > Like-for-like in the code using a bitwise-and mask via vma_flags_and() and > using vma_flags_same() to ensure the final result equals only the required > flag value. > > This is fine but confusing, make things clearer by instead explicitly > excluding undesired flags and including the desired one via tests of the > form: > > if (vma_flags_test(&flags, VMA_FOO_BIT) && > !vma_flags_test_any(&flags, VMA_BAR_BIT, VMA_BAZ_BIT)) { ... } > > Which makes it easier to understand what is going on. > > No functional change intended. > > Suggested-by: Vlastimil Babka (SUSE) > Signed-off-by: Lorenzo Stoakes (Oracle) Acked-by: Vlastimil Babka (SUSE)