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 X-Spam-Level: X-Spam-Status: No, score=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC98DC433E1 for ; Mon, 24 Aug 2020 09:20:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2C9B20738 for ; Mon, 24 Aug 2020 09:20:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="S1z/AmmN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726610AbgHXJUh (ORCPT ); Mon, 24 Aug 2020 05:20:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730496AbgHXJUa (ORCPT ); Mon, 24 Aug 2020 05:20:30 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 281F4C061574 for ; Mon, 24 Aug 2020 02:20:29 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id n3so2949783pjq.1 for ; Mon, 24 Aug 2020 02:20:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=KQzdEJUadSVD+lgD6sVSSDMTvkRGkwdel+4+TdgeUE4=; b=S1z/AmmNOCH9afSNr/qrDInALgK0j4q5VYp45vGoszL08gQOq77XWvhovm91maa4+P FqKO0IvQQ1zgFOTeD7xwiYdXCC4eSy866y0i4iOHUdhtIcu9OyTLXqq9sIjITeHIlDP/ TqDQL3++BGqzXH8U95cUEVFQg9f7Oyelz1pTusAebmjo7UGy1iK4oNwyu8zu1fDcAfPX nbF7uSCxB/11Zqo85kx55hx/wYlWNGXWIUW2MXqUz8acgYZGRkoKmiKOAMbN76qrQ5Ur CsLY7wA5OwEKSwWBknbMM6OhsOsgmjQ3BQKlOzM52TKrjGMbACD7aubcslrIXV21mpIp D4Mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=KQzdEJUadSVD+lgD6sVSSDMTvkRGkwdel+4+TdgeUE4=; b=ACGQwWkyFAU9oHr1qBZRTOjAJ8NvROhjbVzg30DsGHvrVP0TFfVqu/+i3+4azQ5Qpp gX1rTOrEI5WKrV1tzD236RM9CH17QIuRLIeg6z8PICKmMGAH/qVN0DZSyT5i1lbkMqsE 7aGefyof7Bp96iJKxMXx6hkDnYNBrZSu36l+As9bJtoeUeda563Xp0b5GmF2VOakltXR 8quaFsMyJmgpdkVpvIsI97ju+8fQE/xDoRBhZ/rzHGuWZxhZftmRYIbt6Fa4+bSSK/XW nKr0ET0wDL7xgxnmMt0/GnghqCWz7emahMBIpjwymuDB11yGxV3PM0CNe/m7/qynjtG5 nE7Q== X-Gm-Message-State: AOAM53061unMjGEwLiykHECOAFCgLNdVJQZFKTgQJLlJPhxyoOJIKHBs qBSn4QPYtZzTRoWguQiX3raIRA== X-Google-Smtp-Source: ABdhPJyCrZvD6mxlThjGGxFBbEkhy5RNyLB5+uuwXeW5h1XhNu5PQ5mV/pcyDAllrzYkYjEheHn/mA== X-Received: by 2002:a17:90a:f994:: with SMTP id cq20mr3717444pjb.229.1598260828641; Mon, 24 Aug 2020 02:20:28 -0700 (PDT) Received: from [192.168.1.182] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id x144sm897257pfc.82.2020.08.24.02.20.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 Aug 2020 02:20:27 -0700 (PDT) Subject: Re: [PATCH 4/5] bio: introduce BIO_FOLL_PIN flag To: Christoph Hellwig , John Hubbard Cc: Andrew Morton , Alexander Viro , Ilya Dryomov , Jeff Layton , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, ceph-devel@vger.kernel.org, linux-mm@kvack.org, LKML References: <20200822042059.1805541-1-jhubbard@nvidia.com> <20200822042059.1805541-5-jhubbard@nvidia.com> <20200823062559.GA32480@infradead.org> From: Jens Axboe Message-ID: Date: Mon, 24 Aug 2020 03:20:26 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200823062559.GA32480@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 8/23/20 12:25 AM, Christoph Hellwig wrote: > On Fri, Aug 21, 2020 at 09:20:58PM -0700, John Hubbard wrote: >> Add a new BIO_FOLL_PIN flag to struct bio, whose "short int" flags field >> was full, thuse triggering an expansion of the field from 16, to 32 >> bits. This allows for a nice assertion in bio_release_pages(), that the >> bio page release mechanism matches the page acquisition mechanism. >> >> Set BIO_FOLL_PIN whenever pin_user_pages_fast() is used, and check for >> BIO_FOLL_PIN before using unpin_user_page(). > > When would the flag not be set when BIO_NO_PAGE_REF is not set? > > Also I don't think we can't just expand the flags field, but I can send > a series to kill off two flags. (not relevant to this series as this patch has thankfully already been dropped, just in general - but yes, definitely need a *strong* justification to bump the bio size). Would actually be nice to kill off a few flags, if possible, so the flags space isn't totally full. -- Jens Axboe