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 0B4A7CA9ECE for ; Thu, 31 Oct 2019 23:35:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF9CE208E3 for ; Thu, 31 Oct 2019 23:35:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727648AbfJaXfW (ORCPT ); Thu, 31 Oct 2019 19:35:22 -0400 Received: from mga01.intel.com ([192.55.52.88]:53761 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbfJaXfV (ORCPT ); Thu, 31 Oct 2019 19:35:21 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Oct 2019 16:35:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,253,1569308400"; d="scan'208";a="206259359" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by FMSMGA003.fm.intel.com with ESMTP; 31 Oct 2019 16:35:19 -0700 Date: Thu, 31 Oct 2019 16:35:19 -0700 From: Ira Weiny 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" , 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 08/19] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() Message-ID: <20191031233519.GH14771@iweiny-DESK2.sc.intel.com> References: <20191030224930.3990755-1-jhubbard@nvidia.com> <20191030224930.3990755-9-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030224930.3990755-9-jhubbard@nvidia.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Wed, Oct 30, 2019 at 03:49:19PM -0700, John Hubbard wrote: > Convert process_vm_access to use the new pin_user_pages_remote() > call, which sets FOLL_PIN. Setting FOLL_PIN is now required for > code that requires tracking of pinned pages. > > Also, release the pages via put_user_page*(). > > Also, rename "pages" to "pinned_pages", as this makes for > easier reading of process_vm_rw_single_vec(). Ok... but it made review a bit harder... Reviewed-by: Ira Weiny > > Signed-off-by: John Hubbard > --- > mm/process_vm_access.c | 28 +++++++++++++++------------- > 1 file changed, 15 insertions(+), 13 deletions(-) > > diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c > index 357aa7bef6c0..fd20ab675b85 100644 > --- a/mm/process_vm_access.c > +++ b/mm/process_vm_access.c > @@ -42,12 +42,11 @@ static int process_vm_rw_pages(struct page **pages, > if (copy > len) > copy = len; > > - if (vm_write) { > + if (vm_write) > copied = copy_page_from_iter(page, offset, copy, iter); > - set_page_dirty_lock(page); > - } else { > + else > copied = copy_page_to_iter(page, offset, copy, iter); > - } > + > len -= copied; > if (copied < copy && iov_iter_count(iter)) > return -EFAULT; > @@ -96,7 +95,7 @@ static int process_vm_rw_single_vec(unsigned long addr, > flags |= FOLL_WRITE; > > while (!rc && nr_pages && iov_iter_count(iter)) { > - int pages = min(nr_pages, max_pages_per_loop); > + int pinned_pages = min(nr_pages, max_pages_per_loop); > int locked = 1; > size_t bytes; > > @@ -106,14 +105,15 @@ static int process_vm_rw_single_vec(unsigned long addr, > * current/current->mm > */ > down_read(&mm->mmap_sem); > - pages = get_user_pages_remote(task, mm, pa, pages, flags, > - process_pages, NULL, &locked); > + pinned_pages = pin_user_pages_remote(task, mm, pa, pinned_pages, > + flags, process_pages, > + NULL, &locked); > if (locked) > up_read(&mm->mmap_sem); > - if (pages <= 0) > + if (pinned_pages <= 0) > return -EFAULT; > > - bytes = pages * PAGE_SIZE - start_offset; > + bytes = pinned_pages * PAGE_SIZE - start_offset; > if (bytes > len) > bytes = len; > > @@ -122,10 +122,12 @@ static int process_vm_rw_single_vec(unsigned long addr, > vm_write); > len -= bytes; > start_offset = 0; > - nr_pages -= pages; > - pa += pages * PAGE_SIZE; > - while (pages) > - put_page(process_pages[--pages]); > + nr_pages -= pinned_pages; > + pa += pinned_pages * PAGE_SIZE; > + > + /* If vm_write is set, the pages need to be made dirty: */ > + put_user_pages_dirty_lock(process_pages, pinned_pages, > + vm_write); > } > > return rc; > -- > 2.23.0 >