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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D9F99C61DBE for ; Tue, 25 Aug 2026 11:08:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DE6366B00A4; Tue, 25 Aug 2026 07:08:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D97976B00A5; Tue, 25 Aug 2026 07:08:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C850C6B00A7; Tue, 25 Aug 2026 07:08:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id A04AB6B00A4 for ; Tue, 25 Aug 2026 07:08:46 -0400 (EDT) Received: from smtpin03.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 26858403AB for ; Tue, 25 Aug 2026 11:08:46 +0000 (UTC) X-FDA: 85139519052.03.62A1B8C Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf29.hostedemail.com (Postfix) with ESMTP id 70F9012000E for ; Tue, 25 Aug 2026 11:08:44 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=fr1kC5O7; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf29.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787656124; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FbafY2VwTbcRXjCw+IW3Zrp5SUgLFheVDeMNko0UlpE=; b=SSkdajDy6/rePExM+MzoNmS9pMFLEcpAT8Kar0eK5uAWjGju0Y1BQULUm/SZccMyxoLXhm 8KcuMsv45X7wR/br/t50x6wAbaVNkZ6PQOuXr9aEl60uBiorkDpLQaiZu+ZGkTRFsGBkgH VSv3pN+bwGXRSTsVbCyI63oGt0O7mb0= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=fr1kC5O7; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf29.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787656124; b=xh90hak7uVUmQs7bQPwr+N/xI8SVYdJ46QfeZdsG+ukCO2J7uGs0ThHAg+DB3yXreo1PZp g+8bmNwRz+1xI+z0XRf/B0hApNgjcMKUcEyo6iMBviXpVWFiuV6Ts+zrCWorVVXL/rjj35 Zj6dj8Hr90mCR4Izs6r5cvRHkYdrHj4= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id AE4C06011F; Tue, 25 Aug 2026 11:08:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA13E1F000E9; Tue, 25 Aug 2026 11:08:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787656123; bh=FbafY2VwTbcRXjCw+IW3Zrp5SUgLFheVDeMNko0UlpE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=fr1kC5O7u52AQcmSM8hOLx4OrGvSW/CTEZ4sSs4aQLuFyajHVZd5CanV9rVXwvLBG /f+Be3jCiJMPtdXBHISfXmye4h9n6BfxvGSRpUdACgs1qH8qWAt0H4vuVyFhLXnkkF YUzDKaF6uHIgV8ZQ7TypSbFNfk4bkaUGfAL8dFtVWHGzSbCEzfhVdkjTkk/Mv2N/vC 2MEfhOGTBU8nWaIiXZoJI17LzByAmA3u8ru6tjVKURuJN2niwhdC9lQbjPX1KTEL7d M72dcifVPZV3eSqEIVHwZBnbiq22TrfILYJNlhNM9W7goD1ZyTwSkcwaDgY0K6agxj YYoaITxLum8eQ== Message-ID: <1bd9eac9-e078-42c2-b12c-bd8b92efeae5@kernel.org> Date: Tue, 25 Aug 2026 13:08:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/6] userfaultfd: decouple fault reason from VMA flags To: Mike Rapoport , "Lorenzo Stoakes (ARM)" Cc: Andrew Morton , Baolin Wang , Barry Song , Dev Jain , Hugh Dickins , Jann Horn , Jason Gunthorpe , John Hubbard , Jonathan Corbet , Lance Yang , "Liam R. Howlett" , Masami Hiramatsu , Mathieu Desnoyers , Michal Hocko , Muchun Song , Nico Pache , Oscar Salvador , Pedro Falcato , Peter Xu , Ryan Roberts , Shakeel Butt , Shuah Khan , Steven Rostedt , Suren Baghdasaryan , Usama Arif , Vlastimil Babka , Zi Yan , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org References: <20260823-uffd-vm-flags-v1-v1-0-3086981b33cf@kernel.org> <20260823-uffd-vm-flags-v1-v1-5-3086981b33cf@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 1ua3x78srx7waepepfchgi7heum7m9kq X-Rspamd-Queue-Id: 70F9012000E X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1787656124-673641 X-HE-Meta: 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 +l44qQA7 n5Q6B05b+R5iUAb7hFAPm8O+RsPNLgojm2ZmUmKvi6ZO3HNxyYACR9De8TEuaYqu3iUdOsCjgPChYwo+dc52NFQTcR3juw8AT4nGSxVrBBYkuN+zpvzizNyMo/q5LzEv4dhQ1bY7F/2qfQAelcGqXR7TEUztucecAevS6zYBJy6F0GUb8u0xnGLKqJaKFRH2hQVX6ex6Pz4j01wa1VYJ46ARlNNumyICPOQU+SWZ9DqXTwdzBdqLm8mI/MIhQZptx6Zz/ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >>> @@ -2793,14 +2793,14 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, >>> * If VMA has UFFD WP faults enabled and WP fault, wait for userspace to >>> * resolve the fault. >>> */ >>> - if (!pte_write(ptent) && (reason & VM_UFFD_WP)) >>> + if (!pte_write(ptent) && (reason & USERFAULT_WP)) >> >> I wonder if you could actually >> >> You do this quite a lot and they read a bit horribly with the && and & on the >> same sight-line. With the changes to the enum proposed above you could do: >> >> if (!pte_write(ptent) && test_bit(reason, USERFAULT_WP_BIT)) > > I find && and & perfectly readable and adding _BIT defines looks really > excessive to me. Yeah, that looks alright to me as well. -- Cheers, David