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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 E6E1AC432C0 for ; Mon, 18 Nov 2019 12:01:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5F3320895 for ; Mon, 18 Nov 2019 12:01:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727302AbfKRMBs (ORCPT ); Mon, 18 Nov 2019 07:01:48 -0500 Received: from mx2.suse.de ([195.135.220.15]:37574 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726895AbfKRMB1 (ORCPT ); Mon, 18 Nov 2019 07:01:27 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E731CB061; Mon, 18 Nov 2019 12:01:20 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 7EC421E4B09; Mon, 18 Nov 2019 11:16:58 +0100 (CET) Date: Mon, 18 Nov 2019 11:16:58 +0100 From: Jan Kara To: John Hubbard Cc: 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" , Ira Weiny , 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 v5 11/24] goldish_pipe: convert to pin_user_pages() and put_user_page() Message-ID: <20191118101658.GG17319@quack2.suse.cz> References: <20191115055340.1825745-1-jhubbard@nvidia.com> <20191115055340.1825745-12-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191115055340.1825745-12-jhubbard@nvidia.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu 14-11-19 21:53:27, John Hubbard wrote: > 1. Call the new global pin_user_pages_fast(), from pin_goldfish_pages(). > > 2. As required by pin_user_pages(), release these pages via > put_user_page(). In this case, do so via put_user_pages_dirty_lock(). > > That has the side effect of calling set_page_dirty_lock(), instead > of set_page_dirty(). This is probably more accurate. > > As Christoph Hellwig put it, "set_page_dirty() is only safe if we are > dealing with a file backed page where we have reference on the inode it > hangs off." [1] > > Another side effect is that the release code is simplified because > the page[] loop is now in gup.c instead of here, so just delete the > local release_user_pages() entirely, and call > put_user_pages_dirty_lock() directly, instead. > > [1] https://lore.kernel.org/r/20190723153640.GB720@lst.de > > Reviewed-by: Ira Weiny > Signed-off-by: John Hubbard Looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > drivers/platform/goldfish/goldfish_pipe.c | 17 +++-------------- > 1 file changed, 3 insertions(+), 14 deletions(-) > > diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c > index 7ed2a21a0bac..635a8bc1b480 100644 > --- a/drivers/platform/goldfish/goldfish_pipe.c > +++ b/drivers/platform/goldfish/goldfish_pipe.c > @@ -274,7 +274,7 @@ static int pin_goldfish_pages(unsigned long first_page, > *iter_last_page_size = last_page_size; > } > > - ret = get_user_pages_fast(first_page, requested_pages, > + ret = pin_user_pages_fast(first_page, requested_pages, > !is_write ? FOLL_WRITE : 0, > pages); > if (ret <= 0) > @@ -285,18 +285,6 @@ static int pin_goldfish_pages(unsigned long first_page, > return ret; > } > > -static void release_user_pages(struct page **pages, int pages_count, > - int is_write, s32 consumed_size) > -{ > - int i; > - > - for (i = 0; i < pages_count; i++) { > - if (!is_write && consumed_size > 0) > - set_page_dirty(pages[i]); > - put_page(pages[i]); > - } > -} > - > /* Populate the call parameters, merging adjacent pages together */ > static void populate_rw_params(struct page **pages, > int pages_count, > @@ -372,7 +360,8 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe, > > *consumed_size = pipe->command_buffer->rw_params.consumed_size; > > - release_user_pages(pipe->pages, pages_count, is_write, *consumed_size); > + put_user_pages_dirty_lock(pipe->pages, pages_count, > + !is_write && *consumed_size > 0); > > mutex_unlock(&pipe->lock); > return 0; > -- > 2.24.0 > -- Jan Kara SUSE Labs, CR