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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 53E2DC43441 for ; Wed, 10 Oct 2018 23:44:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 036C32086D for ; Wed, 10 Oct 2018 23:44:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 036C32086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726300AbeJKHIa (ORCPT ); Thu, 11 Oct 2018 03:08:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54146 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725968AbeJKHI3 (ORCPT ); Thu, 11 Oct 2018 03:08:29 -0400 Received: from localhost.localdomain (c-24-4-154-175.hsd1.ca.comcast.net [24.4.154.175]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id D7D3BA85; Wed, 10 Oct 2018 23:44:00 +0000 (UTC) Date: Wed, 10 Oct 2018 16:43:59 -0700 From: Andrew Morton To: John Hubbard Cc: Jan Kara , , Matthew Wilcox , Michal Hocko , Christopher Lameter , Jason Gunthorpe , Dan Williams , , LKML , linux-rdma , , Al Viro , Jerome Glisse , Christoph Hellwig , Ralph Campbell Subject: Re: [PATCH v4 2/3] mm: introduce put_user_page*(), placeholder versions Message-Id: <20181010164359.292d938b51cbd57b38a1bd99@linux-foundation.org> In-Reply-To: <62492f47-d51f-5c41-628c-ff17de21829e@nvidia.com> References: <20181008211623.30796-1-jhubbard@nvidia.com> <20181008211623.30796-3-jhubbard@nvidia.com> <20181008171442.d3b3a1ea07d56c26d813a11e@linux-foundation.org> <20181009083025.GE11150@quack2.suse.cz> <20181009162012.c662ef0b041993557e150035@linux-foundation.org> <62492f47-d51f-5c41-628c-ff17de21829e@nvidia.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Oct 2018 17:32:16 -0700 John Hubbard wrote: > > I'm not really understanding. Patch 3/3 changes just one infiniband > > driver to use put_user_page(). But the changelogs here imply (to me) > > that every user of get_user_pages() needs to be converted to > > s/put_page/put_user_page/. > > > > Methinks a bit more explanation is needed in these changelogs? > > > > OK, yes, it does sound like the explanation is falling short. I'll work on something > clearer. Did the proposed steps in the changelogs, such as: > > [2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubbard@nvidia.com > Proposed steps for fixing get_user_pages() + DMA problems. > > help at all, or is it just too many references, and I should write the words > directly in the changelog? > > Anyway, patch 3/3 is a just a working example (which we do want to submit, though), and > many more conversions will follow. But they don't have to be done all upfront--they > can be done in follow up patchsets. > > The put_user_page*() routines are, at this point, not going to significantly change > behavior. > > I'm working on an RFC that will show what the long-term fix to get_user_pages and > put_user_pages will look like. But meanwhile it's good to get started on converting > all of the call sites. I see. Yes, please do put all of it into the changelog[s].