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 06D7EC61DC7 for ; Thu, 27 Aug 2026 07:49:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 29B1E6B008A; Thu, 27 Aug 2026 03:49:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 24BC86B008C; Thu, 27 Aug 2026 03:49:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 13D2C6B0098; Thu, 27 Aug 2026 03:49:47 -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 E7AEF6B008A for ; Thu, 27 Aug 2026 03:49:46 -0400 (EDT) Received: from smtpin20.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 66AF516032A for ; Thu, 27 Aug 2026 07:49:46 +0000 (UTC) X-FDA: 85146275172.20.5490506 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf24.hostedemail.com (Postfix) with ESMTP id C0E2A180009 for ; Thu, 27 Aug 2026 07:49:44 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=XP5GUoKs; spf=pass (imf24.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787816984; 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=pXKPSGKEnYpUCi4b1Zk1PpaxxASDBVDKKvWhbUsQzzE=; b=8ENvzJ+fo+lEeGqP38sY99I4R5RrF0uS0kq8YTrK3cAJP9G9m8TykhJmqtS9fRaV/GGhJV zEtqVTOotAndOTMZf3hC/7ZFuqajseoUe56NTcYxHoKcw3W10nmIDGfCVzDIEQ1T3P7WgB HD6xNyviCFQosijAjsjFBwcaItIFXG0= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=XP5GUoKs; spf=pass (imf24.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787816984; b=LjxFr+S/d2vc1fvE3zQTNKLDyvgdQSFV5u78hQmJ9sPafbKFbT0M8kuCL/hs99qQleSECu S9+EiTKH1PMA7Bzzp6Q39oKw7aYZX3U4td/d11l7bmiEBpKpRUOAqpve6JQL/4tfILPnvf 8qNsfQlaOJCMZNFPwhiC3b4AoRsTjxE= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 03E3442E08; Thu, 27 Aug 2026 07:49:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1DFB1F000E9; Thu, 27 Aug 2026 07:49:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787816983; bh=pXKPSGKEnYpUCi4b1Zk1PpaxxASDBVDKKvWhbUsQzzE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XP5GUoKscwLfu7Wd9nUZA5nENI+S/18k7abGqbbmVOSzWIZOZFrV9h7aPu5Asmf7U OwJFJSoNI9m1vYcI4QoNpM5xvoy8mOk6jaM1Q97ewpFzcC1YTjN1uSUpnYNCOKnOwk 6j7TJRULs5vWsgaNPseFCq3o9vlEli8peP2xq6qfnlFJ60vivszWc0cYPoskntdmIv +q4aMFrl0i+M+oKTIqkT1+z5EdtxBtdRNeTn9qouluLVwxVfm7s09i/032hvBQHd+D d/tiFEHJfC3XWiDyJzXWpQM4SBVsoSAqHACxmgKU+e97L6OVESE17Qpvxy508ZLpxM mF/83rFlBH63Q== Date: Thu, 27 Aug 2026 10:49:30 +0300 From: Mike Rapoport To: "David Hildenbrand (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" , Lorenzo Stoakes , 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> <5bb86e34-6196-4b50-b553-be2ff7c1fa32@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5bb86e34-6196-4b50-b553-be2ff7c1fa32@kernel.org> X-Stat-Signature: ajphe9zchjyqfubwyq7wk9rtjkcfd9z3 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: C0E2A180009 X-Rspam-User: X-HE-Tag: 1787816984-975064 X-HE-Meta: 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 jR1pt3so ixb36WJ3pW5VOl7ET34D8QG7/H912xeGzVxMczl9v5XIWtmrMKURcPSKN7q9Bg06essbpTOY6XMWZ7tSt2Z1tkRhyTTiIAH2VNUFDPLZKg1Ull74MjyYdyN5FbpObDIO0qlEzKdKu6kvCHGXPrQ4QGVC2SSuJekjWLO3Qoz9dIzaFdIFI4pIdbHahs2YmU4kAEEeQNTxr0BuoxIcVNCgfmo3l8jOnqna5CFRnP8RXq4uRqVRW3GS4pEnyfmNDKL5jnaa0jXA4RN/9Lpb7h6w5nC2IGA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 24, 2026 at 04:46:14PM +0200, David Hildenbrand (Arm) wrote: > On 8/23/26 14:17, Mike Rapoport (Microsoft) wrote: > > Introduce enum uffd_reason to define reasons for user faults rather than > > overload VM_UFFD_* VMA flags for that. > > > > Using a dedicated enum makes the code clearer and decoupling the fault > > reason from VMA flags clears the way for moving the uffd mode bits out > > of VMA namespace. > > > > No functional change. > > > > Assisted-by: copilot:claude-opus-4.6 > > Signed-off-by: Mike Rapoport (Microsoft) > > --- > > include/linux/userfaultfd_k.h | 16 ++++++++++++++-- > > include/uapi/linux/userfaultfd.h | 6 +++--- > > mm/huge_memory.c | 6 +++--- > > mm/hugetlb.c | 10 +++++----- > > mm/memory.c | 10 +++++----- > > mm/shmem.c | 4 ++-- > > mm/userfaultfd.c | 30 +++++++++++++++--------------- > > 7 files changed, 47 insertions(+), 35 deletions(-) > > > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > > index 45355bdb4ec7..f401623f315d 100644 > > --- a/include/linux/userfaultfd_k.h > > +++ b/include/linux/userfaultfd_k.h > > @@ -9,6 +9,18 @@ > > #ifndef _LINUX_USERFAULTFD_K_H > > #define _LINUX_USERFAULTFD_K_H > > > > +#include > > + > > +/* Fault reason #PF handler passes to handle_userfault() */ > > +enum uf_reason { > > Can we just call this "userfault_reason" or "uffd_reason" ? Maybe the latter is > actually what we want? userfault_reason sounds better to me. It describes what kind of user fault we are handling and the 'fd' part has nothing to do with it. We do use uffd as a short name for the subsystem, but still most if not all userfaultfd "external" APIs use userfault_ prefix. uf_ was an attempt to make it wee shorter :) > -- > Cheers, > David -- Sincerely yours, Mike.