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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 EFCA2FC6196 for ; Thu, 7 Nov 2019 02:25:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB99B21848 for ; Thu, 7 Nov 2019 02:25:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733009AbfKGCZK (ORCPT ); Wed, 6 Nov 2019 21:25:10 -0500 Received: from mga12.intel.com ([192.55.52.136]:35901 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727778AbfKGCZK (ORCPT ); Wed, 6 Nov 2019 21:25:10 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Nov 2019 18:25:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,276,1569308400"; d="scan'208";a="227685020" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by fmsmga004.fm.intel.com with ESMTP; 06 Nov 2019 18:25:08 -0800 Date: Wed, 6 Nov 2019 18:25:08 -0800 From: Ira Weiny To: John Hubbard Cc: Mike Rapoport , Andrew Morton , Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?iso-8859-1?B?Suly9G1l?= Glisse , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , bpf@vger.kernel.org, dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org, linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-mm@kvack.org, LKML Subject: Re: [PATCH v2 05/18] mm/gup: introduce pin_user_pages*() and FOLL_PIN Message-ID: <20191107022508.GB32084@iweiny-DESK2.sc.intel.com> References: <20191103211813.213227-1-jhubbard@nvidia.com> <20191103211813.213227-6-jhubbard@nvidia.com> <20191105131032.GG25005@rapoport-lnx> <9ac948a4-59bf-2427-2007-e460aad2848a@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ac948a4-59bf-2427-2007-e460aad2848a@nvidia.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > ... > >> +This document describes the following functions: :: > >> + > >> + pin_user_pages > >> + pin_user_pages_fast > >> + pin_user_pages_remote > >> + > >> + pin_longterm_pages > >> + pin_longterm_pages_fast > >> + pin_longterm_pages_remote > >> + > >> +Basic description of FOLL_PIN > >> +============================= > >> + > >> +A new flag for get_user_pages ("gup") has been added: FOLL_PIN. FOLL_PIN has > > > > Consider reading this after, say, half a year ;-) > > > > OK, OK. I knew when I wrote that that it was not going to stay new forever, but > somehow failed to write the right thing anyway. :) > > Here's a revised set of paragraphs: > > Basic description of FOLL_PIN > ============================= > > FOLL_PIN and FOLL_LONGTERM are flags that can be passed to the get_user_pages*() > ("gup") family of functions. FOLL_PIN has significant interactions and > interdependencies with FOLL_LONGTERM, so both are covered here. > > Both FOLL_PIN and FOLL_LONGTERM are internal to gup, meaning that neither > FOLL_PIN nor FOLL_LONGTERM should not appear at the gup call sites. This allows > the associated wrapper functions (pin_user_pages() and others) to set the > correct combination of these flags, and to check for problems as well. I like this revision as well. Ira