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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 11094C433E0 for ; Tue, 26 May 2020 22:57:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D88632075F for ; Tue, 26 May 2020 22:57:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="GAmK3J9Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404597AbgEZW5r (ORCPT ); Tue, 26 May 2020 18:57:47 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:5598 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403871AbgEZW5q (ORCPT ); Tue, 26 May 2020 18:57:46 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 26 May 2020 15:56:17 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 26 May 2020 15:57:46 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 26 May 2020 15:57:46 -0700 Received: from [10.2.50.17] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 26 May 2020 22:57:45 +0000 Subject: Re: [PATCH] drm/radeon: Convert get_user_pages() --> pin_user_pages() To: Souptick Joarder , , , , CC: , , References: <1590526802-3008-1-git-send-email-jrdr.linux@gmail.com> X-Nvconfidentiality: public From: John Hubbard Message-ID: <69a033cf-63b2-7da6-6a5e-a5bbc94b8afb@nvidia.com> Date: Tue, 26 May 2020 15:57:45 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <1590526802-3008-1-git-send-email-jrdr.linux@gmail.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1590533777; bh=+/fm5fCUttIpqWTs0jSX13YUVmAx0K1Rl+iVpdhLRU4=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=GAmK3J9YLRYobQGF3pU5h7D1OHgDb3X9cRCMTdfTrpn9a6Ug+ktStJkaSedHNhev7 Fo0vLXo87hVswKPIZrVmA4Qad4UngVJEtHMrQH6kwS9m4O6rMu72TLsc0S0AgpXtp0 6YrG8FclCWX5vGNFF0Z9qZftM0wEKd9HoofGhsVFt/HwaXv+MgZhVZTAdTs1Xfnfbv kVSbGn0HLF8g3M/GXt6hCipT4+nlfZjlc+fjVw48lSwCraUg53VW+Jbc/m5oQrP4h+ /0B7f5m2/ezoX/4zBj0oJOW8iGBUcdUjgFfggXIl8HMpaNNy0dCV3q1BwLksAfrQ/w 3HQlFGHaa5r1w== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-05-26 14:00, Souptick Joarder wrote: > This code was using get_user_pages(), in a "Case 2" scenario > (DMA/RDMA), using the categorization from [1]. That means that it's > time to convert the get_user_pages() + release_pages() calls to > pin_user_pages() + unpin_user_pages() calls. > > There is some helpful background in [2]: basically, this is a small > part of fixing a long-standing disconnect between pinning pages, and > file systems' use of those pages. > > [1] Documentation/core-api/pin_user_pages.rst > > [2] "Explicit pinning of user-space pages": > https://lwn.net/Articles/807108/ > > Signed-off-by: Souptick Joarder > Cc: John Hubbard > > Hi, > > I'm compile tested this, but unable to run-time test, so any testing > help is much appriciated. > --- > drivers/gpu/drm/radeon/radeon_ttm.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c > index 5d50c9e..e927de2 100644 > --- a/drivers/gpu/drm/radeon/radeon_ttm.c > +++ b/drivers/gpu/drm/radeon/radeon_ttm.c > @@ -506,7 +506,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm) > uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE; > struct page **pages = ttm->pages + pinned; > > - r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0, > + r = pin_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0, > pages, NULL); > if (r < 0) > goto release_pages; > @@ -535,7 +535,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm) > kfree(ttm->sg); > > release_pages: > - release_pages(ttm->pages, pinned); > + unpin_user_pages(ttm->pages, pinned); > return r; > } > > @@ -562,7 +562,7 @@ static void radeon_ttm_tt_unpin_userptr(struct ttm_tt *ttm) > set_page_dirty(page); Maybe we also need a preceding patch, to fix the above? It should be set_page_dirty_lock(), rather than set_page_dirty(), unless I'm overlooking something (which is very possible!). Either way, from a tunnel vision perspective of changing gup to pup, this looks good to me, so Acked-by: John Hubbard thanks, -- John Hubbard NVIDIA > > mark_page_accessed(page); > - put_page(page); > + unpin_user_page(page); > } > > sg_free_table(ttm->sg); >