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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 D137CC432C3 for ; Wed, 13 Nov 2019 20:22:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6102E206F0 for ; Wed, 13 Nov 2019 20:22:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="n1t9MMHi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6102E206F0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 283EA6B0003; Wed, 13 Nov 2019 15:22:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 234EF6B0005; Wed, 13 Nov 2019 15:22:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 123DD6B0006; Wed, 13 Nov 2019 15:22:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0252.hostedemail.com [216.40.44.252]) by kanga.kvack.org (Postfix) with ESMTP id F25A86B0003 for ; Wed, 13 Nov 2019 15:22:41 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 98A13180AD807 for ; Wed, 13 Nov 2019 20:22:41 +0000 (UTC) X-FDA: 76152377322.07.plate87_517dbba5d052c X-HE-Tag: plate87_517dbba5d052c X-Filterd-Recvd-Size: 5173 Received: from hqemgate15.nvidia.com (hqemgate15.nvidia.com [216.228.121.64]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Wed, 13 Nov 2019 20:22:39 +0000 (UTC) Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 13 Nov 2019 12:22:35 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Wed, 13 Nov 2019 12:22:36 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Wed, 13 Nov 2019 12:22:36 -0800 Received: from [10.2.160.107] (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 13 Nov 2019 20:22:35 +0000 Subject: Re: [PATCH v4 08/23] vfio, mm: fix get_user_pages_remote() and FOLL_LONGTERM To: Ira Weiny , Jason Gunthorpe CC: Andrew Morton , Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Jan Kara , Jens Axboe , Jonathan Corbet , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , , , , , , , , , , , , , LKML References: <20191113042710.3997854-1-jhubbard@nvidia.com> <20191113042710.3997854-9-jhubbard@nvidia.com> <20191113130202.GA26068@ziepe.ca> <20191113191705.GE12947@iweiny-DESK2.sc.intel.com> From: John Hubbard X-Nvconfidentiality: public Message-ID: <290ba4aa-247e-6570-9eff-ccf2087e1120@nvidia.com> Date: Wed, 13 Nov 2019 12:19:50 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191113191705.GE12947@iweiny-DESK2.sc.intel.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) 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=1573676555; bh=FW0krwPwWqciO/Z2LS4wGz5Cikl4rg4mIFXWQ1mXpqU=; h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=n1t9MMHier43EuFZpftpwQVDKG8oSo9TdOvV+OMzrOIN0Kprv6dkR4Jpu6/PqCqXm /jCxLMJDxPPXF7oklQ45MeW/Fl3jyAJJ4cfyLvk1YJ3ZXQloakTUN/6QsjTZ2e8wLd Vi5ItQz0+ykvg9G6LEUGgX0gLMaFmq2awJU2Kk5qVpihlMSAmAuGK9LjnFEEtlsHOE JOaWrzJR8vtoHRO1QeIa0YnKmF32io8xAGlhrbiuGj5eUhM/rh5jJ0AdTIvnBhqGbA tSsPrYCj4XsKBHj/d5S4XMsaWdBoBg5n+7WnTPKexUFAUitbBsugmf2TNoS/6cs3Dr dZibHSHNj0z1Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 11/13/19 11:17 AM, Ira Weiny wrote: ... >>> @@ -348,33 +347,13 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, >>> flags |= FOLL_WRITE; >>> >>> down_read(&mm->mmap_sem); >>> - if (mm == current->mm) { >>> - ret = get_user_pages(vaddr, 1, flags | FOLL_LONGTERM, page, >>> - vmas); >>> - } else { >>> - ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page, >>> - vmas, NULL); >>> - /* >>> - * The lifetime of a vaddr_get_pfn() page pin is >>> - * userspace-controlled. In the fs-dax case this could >>> - * lead to indefinite stalls in filesystem operations. >>> - * Disallow attempts to pin fs-dax pages via this >>> - * interface. >>> - */ >>> - if (ret > 0 && vma_is_fsdax(vmas[0])) { >>> - ret = -EOPNOTSUPP; >>> - put_page(page[0]); >>> - } >>> - } >>> - up_read(&mm->mmap_sem); >>> - >>> + ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags | FOLL_LONGTERM, >>> + page, NULL, NULL); >>> if (ret == 1) { >>> *pfn = page_to_pfn(page[0]); >>> return 0; >> >> Mind the return with the lock held this needs some goto unwind > > Ah yea... retract my reviewed by... :-( > ooops, embarrassed that I missed that, good catch. Will repost with it fixed. thanks, -- John Hubbard NVIDIA