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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD68BC6FA99 for ; Tue, 7 Mar 2023 01:24:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229841AbjCGBYa (ORCPT ); Mon, 6 Mar 2023 20:24:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229834AbjCGBY2 (ORCPT ); Mon, 6 Mar 2023 20:24:28 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75CA66E89 for ; Mon, 6 Mar 2023 17:23:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678152220; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VqFd56y4+LzHfJxq40JHsrzkzmxYaLDJMh6dCS+VZKQ=; b=C0kAeLZ4m80kQ4W4REDmVUtUNvdH71ufoL66+MFJQcGyuqIkGfNppwFbe4jSHyzbvaQnyj t6xAqIUceq+fI32Pio566tw018E1mehq4s2XcmtiGgimP8DkQojH2Wr+koeHkdsho8PX2Y Imuov6DiiRJ8Uqa3mDmjklKLEbbdtCY= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-368-tyl07KeNOn2ML-TyqfK8-Q-1; Mon, 06 Mar 2023 20:23:39 -0500 X-MC-Unique: tyl07KeNOn2ML-TyqfK8-Q-1 Received: by mail-qk1-f199.google.com with SMTP id e14-20020a05620a208e00b0074270b9960dso6509247qka.22 for ; Mon, 06 Mar 2023 17:23:39 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678152218; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=VqFd56y4+LzHfJxq40JHsrzkzmxYaLDJMh6dCS+VZKQ=; b=4H7LzAYMg8qwrsmdQ1zeBrXqs24dlzWqA1K3JcziZ1E33BnzA/z1uvE75F6ttmAPE7 RqUlwiSyhUeUmA0Vfs9nM67dUY1sRyvY+Cr07qroTfCN6Z8Ms7XGSEAhmJJpPzwQ30fH BxGUfIHJ9+DcPPb7pbiScoFJAUe0QfCTYKxzJcCFXveQvQgfRCVKeEFs5ZXR+FT0QQ/j czV7u+1SUV7XR5VVIb1rBPp0BcpLUAMDfPJqrvLwu0kAwIjeOsljismNEPMfarsQNJEq zfY04HaPXq9L08e5h1TgmfQI3yIOnPaM5WGjYlQbkiYtyZ2u0yOLjg/LfdgKqR9JfCA8 Mjpg== X-Gm-Message-State: AO0yUKXVbgeJ8xymtqnkTNJaTzvtOIQrGOsfvdzCHibC3YwxoVt5DtQ+ 7xDmYymnrorlqYAJmOi2PwL1bbKCkCTbbWlWKQdiD+NSON8q1F5mwwj/JF2kGY41GV+M1X4HZAR 9r+q8N+7MBNLb+xWAMZeDkvu2y3q3hv8UCA== X-Received: by 2002:ac8:4e49:0:b0:3b6:309e:dfe1 with SMTP id e9-20020ac84e49000000b003b6309edfe1mr22807073qtw.3.1678152218570; Mon, 06 Mar 2023 17:23:38 -0800 (PST) X-Google-Smtp-Source: AK7set9NpW+IRYzeTwvzpjcmeG0lCpLiSMH4ix2ZZfLC9vuxmSNZLU9/wHTDN/VWK1ddDO5/7LNY8w== X-Received: by 2002:ac8:4e49:0:b0:3b6:309e:dfe1 with SMTP id e9-20020ac84e49000000b003b6309edfe1mr22807045qtw.3.1678152218368; Mon, 06 Mar 2023 17:23:38 -0800 (PST) Received: from x1n (bras-base-aurron9127w-grc-56-70-30-145-63.dsl.bell.ca. [70.30.145.63]) by smtp.gmail.com with ESMTPSA id e15-20020ac85dcf000000b003bfad864e81sm8708948qtx.69.2023.03.06.17.23.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Mar 2023 17:23:37 -0800 (PST) Date: Mon, 6 Mar 2023 20:23:36 -0500 From: Peter Xu To: Axel Rasmussen Cc: Alexander Viro , Andrew Morton , Hugh Dickins , Jan Kara , "Liam R. Howlett" , Matthew Wilcox , Mike Kravetz , Mike Rapoport , Muchun Song , Nadav Amit , Shuah Khan , James Houghton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v3 5/5] mm: userfaultfd: add UFFDIO_CONTINUE_MODE_WP to install WP PTEs Message-ID: References: <20230306225024.264858-1-axelrasmussen@google.com> <20230306225024.264858-6-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230306225024.264858-6-axelrasmussen@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Mar 06, 2023 at 02:50:24PM -0800, Axel Rasmussen wrote: > UFFDIO_COPY already has UFFDIO_COPY_MODE_WP, so when installing a new > PTE to resolve a missing fault, one can install a write-protected one. > This is useful when using UFFDIO_REGISTER_MODE_{MISSING,WP} in > combination. > > So, add an analogous UFFDIO_CONTINUE_MODE_WP, which does the same thing > but for *minor* faults. > > Update the selftest to do some very basic exercising of the new flag. > > Signed-off-by: Axel Rasmussen Some mentioning on the use case would be nice. :) No objection having it. Acked-by: Peter Xu Thanks, -- Peter Xu