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 11CC8C61DBE for ; Tue, 25 Aug 2026 11:38:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 03C586B009F; Tue, 25 Aug 2026 07:38:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 012CF6B00B6; Tue, 25 Aug 2026 07:38:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E926B6B00B7; Tue, 25 Aug 2026 07:38:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C860D6B009F for ; Tue, 25 Aug 2026 07:38:26 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id A85D51603DD for ; Tue, 25 Aug 2026 11:38:24 +0000 (UTC) X-FDA: 85139593728.01.D16BD31 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf26.hostedemail.com (Postfix) with ESMTP id 2290F14000B for ; Tue, 25 Aug 2026 11:38:22 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=nBsTwrPQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf26.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787657903; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=kYx8aeMEaBJjieFEUuIAbUN5rp+4oyE9/j58DZHMqKw=; b=t66fsLtxF64hg6GTPxD5+Qh6+HU1njuUSJk7DwOgoISZDB8dwr+R5KMFsfW7BFU+x5VDIK pHWYkALdRB2+B21hC+d7WII07y/PKTcE045zqXb5dZmAbCI1y4c+EOyvvFOEw2hOpFMQJA r0G4dCu0hVVw9QCI2n48JIRuY8e5dgs= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=nBsTwrPQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf26.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787657903; b=E2nq+K/jXFjrX+ARlk5VrRo3oikmz2gjprVehkriBjCwAFWnaTmhCAkBN3ElXbD3eKv4T8 Pl+p3y1jLFTcTpEJQg0E8zLNx1AausLb2PyiW8D8Z+oJTzBBs/9gPDfKWnBK192zoS5Th7 HRnjHxRV4jqPwtOlR1hQVI5szHFXW6c= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 9BFEA6013A; Tue, 25 Aug 2026 11:38:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA1C21F000E9; Tue, 25 Aug 2026 11:38:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787657902; bh=kYx8aeMEaBJjieFEUuIAbUN5rp+4oyE9/j58DZHMqKw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=nBsTwrPQM1EQ8ZVvH2h8CSQlt+V+fybz/E5HCoH1g/6G4NmVlh47TTU4WNrrp7BTQ otqVRkJ8bbmT80kozyp9ZvsMUg5aBhbrwe0yHgKbbNAYPIhIaQu02bC2LrQk2qqb9n AB75JmSK9W2uBSF4XKy5BXp7jwWI3ljH6atrax4n1CxRmyLlMV1oJg5csmXS2gGHog fQcR4lL4xGda1kycL3mKxp7F7Ho3WSZUcQ7cAfviSNgwcvlbo1IReMLbNd8TfUU4ZO fIgy01nc4DqVMvUcIHG5+dXyvvi1epORsPRXyxX/D1/XsphHrPL3o2MmxlGgrWv3Bf TaHkq6xODc69A== Date: Tue, 25 Aug 2026 12:38:12 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Mike Rapoport , 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 Subject: Re: [PATCH 5/6] userfaultfd: decouple fault reason from VMA flags Message-ID: References: <20260823-uffd-vm-flags-v1-v1-0-3086981b33cf@kernel.org> <20260823-uffd-vm-flags-v1-v1-5-3086981b33cf@kernel.org> <1bd9eac9-e078-42c2-b12c-bd8b92efeae5@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1bd9eac9-e078-42c2-b12c-bd8b92efeae5@kernel.org> X-Rspam-User: X-Rspamd-Queue-Id: 2290F14000B X-Rspamd-Server: rspam07 X-Stat-Signature: sjz1p9o6ddgxixhtbsrxwbur68gujca9 X-HE-Tag: 1787657902-232201 X-HE-Meta: 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 ou0/TipK 1cl6IvctZktcRAYKL/33sf8n0cPAZK4YIsHtkK9rgaD9LqVM7uXFIc7kijPDCLaeZVe5jOToiVOSHRAUcAf728kUNp7/SHjuE8oZV/4nMhZwsv5lc2X6cC/UMvqoINUWAlhc2vfYBI9RN+GDOF/tM54W+nI4DMikILauKIr4+YhUsZnFH+6VAiFT/92kG+oV5sTc12oQaQvcYhEeSl53cRe2UyLxdP9SCxM6L6PooqI6MGU7G8+LUsMsYMYO9inYVeGvG Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 25, 2026 at 01:08:33PM +0200, David Hildenbrand (Arm) wrote: > > >>> @@ -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. I find the general inconsistent different sets of flags/bits but not really/naming all a bit of a mess. But these are largely aesthetic and I don't maintain this file so I guess you guys can live without my tag here... > > -- > Cheers, > > David -- Cheers, Lorenzo