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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2434AC43331 for ; Wed, 13 Nov 2019 01:36:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DDF5A222D3 for ; Wed, 13 Nov 2019 01:36:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="pgvm7B7M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDF5A222D3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7F23E6B0005; Tue, 12 Nov 2019 20:36:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7A3D86B0006; Tue, 12 Nov 2019 20:36:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 692936B0007; Tue, 12 Nov 2019 20:36:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id 50CF96B0005 for ; Tue, 12 Nov 2019 20:36:00 -0500 (EST) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id E4DD68249980 for ; Wed, 13 Nov 2019 01:35:59 +0000 (UTC) X-FDA: 76149538038.10.wash95_8b719e5125826 X-HE-Tag: wash95_8b719e5125826 X-Filterd-Recvd-Size: 5851 Received: from mail-ot1-f67.google.com (mail-ot1-f67.google.com [209.85.210.67]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Wed, 13 Nov 2019 01:35:58 +0000 (UTC) Received: by mail-ot1-f67.google.com with SMTP id z9so197475otq.6 for ; Tue, 12 Nov 2019 17:35:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tA9TOCxBga9LLC7wRjd3ONed6e5UCLIuIdqzN/pcWuk=; b=pgvm7B7MKRNHPnnm+UXqpNAxEKn59mgIkjpVIugT59Mu8TwvXIAzzyQhvDiVCxIl0p vI+Yj+13Wusmq5tADceFQlsKUjuwgmmDrjkNeYGEIUHh9w8tZNldmP6Q5WtjVpISdJ0i r3oVh4apWhwsDdj9Nw0bWAyVdq8zxIhXTRj/8PmhzFCoHQ/9X/Dg5B4Hj6Y0ruPyQaaR rEPfI8qEDLrnHlL1idX+oRviz/9wQZUiz6o40remYNFeKqLceiYDgbAXk1ppNt84zSqw zf+6WmCRWk7Wod/xBPOURyhyWoKZqScoLNTr5ASvgI3i5qH5c+mNJETCAbPrPmJU7Yqj fNKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tA9TOCxBga9LLC7wRjd3ONed6e5UCLIuIdqzN/pcWuk=; b=UBmT0RLMyjOrwYxcCdsm1fFmoziRM8DbWzWUCkE29ZaF3nD40nAGsxudsf/5siRIZ4 6qZQyaVKfJRQlouZt/9fboSi8UgkOOSR1Cmy1O8+YDbhW9rigD+fpihXfzQAKNA9F588 eNtr8LhkK2WtXSlV+HGOELd2udJm2Y8NCHD/SZBH8i7tvzqt63g86DA15bfCv39L6Wi3 m0Q8Wi8FPdIfuEErBEejudoOkLrHMJFLMzVCotWRerdHCsX7z9AaEkG2xb7A80GBYSv9 Knd/FviYgMO2lqQpGPuAJGGsk2PfTIsV+DH4217zhQYt4HsUfy1WLMYUf+eT2kBd082g pVcA== X-Gm-Message-State: APjAAAXciui0ic07QBXGEg6SnL1CSaKau2ZVxN3inYoU/scwyUV4j6ql sjLJNQ/ML5u7ej/Y4QQTymq2UtSVjFe5CBHUieanzw== X-Google-Smtp-Source: APXvYqzyV061KEXPKPAkyAkGRgXJ6fWU+P7KwNCWCXXtSomJ5IUaejCErE/o1rH0NBMapixozrDCWZBdHagrZr75cJE= X-Received: by 2002:a05:6830:1b70:: with SMTP id d16mr411248ote.71.1573608957281; Tue, 12 Nov 2019 17:35:57 -0800 (PST) MIME-Version: 1.0 References: <20191112000700.3455038-1-jhubbard@nvidia.com> <20191112000700.3455038-9-jhubbard@nvidia.com> <20191112204338.GE5584@ziepe.ca> <0db36e86-b779-01af-77e7-469af2a2e19c@nvidia.com> <20191112234250.GA19615@ziepe.ca> <28355eb0-4ee5-3418-b430-59302d15b478@nvidia.com> In-Reply-To: <28355eb0-4ee5-3418-b430-59302d15b478@nvidia.com> From: Dan Williams Date: Tue, 12 Nov 2019 17:35:46 -0800 Message-ID: Subject: Re: [PATCH v3 08/23] vfio, mm: fix get_user_pages_remote() and FOLL_LONGTERM To: John Hubbard Cc: Jason Gunthorpe , Andrew Morton , Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Christoph Hellwig , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Ira Weiny , 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 , bpf@vger.kernel.org, Maling list - DRI developers , KVM list , linux-block@vger.kernel.org, Linux Doc Mailing List , linux-fsdevel , linux-kselftest@vger.kernel.org, "Linux-media@vger.kernel.org" , linux-rdma , linuxppc-dev , Netdev , Linux MM , LKML Content-Type: text/plain; charset="UTF-8" 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 Tue, Nov 12, 2019 at 5:08 PM John Hubbard wrote: > > On 11/12/19 4:58 PM, Dan Williams wrote: > ... > >>> It's not redundant relative to upstream which does not do anything the > >>> FOLL_LONGTERM in the gup-slow path... but I have not looked at patches > >>> 1-7 to see if something there made it redundant. > >> > >> Oh, the hunk John had below for get_user_pages_remote() also needs to > >> call __gup_longterm_locked() when FOLL_LONGTERM is specified, then > >> that calls check_dax_vmas() which duplicates the vma_is_fsdax() check > >> above. > > > > Oh true, good eye. It is redundant if it does additionally call > > __gup_longterm_locked(), and it needs to do that otherwises it undoes > > the CMA migration magic that Aneesh added. > > > > OK. So just to be clear, I'll be removing this from the patch: > > /* > * 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]); > } > > (and the declaration of "vmas", as well). ...and add a call to __gup_longterm_locked internal to get_user_pages_remote(), right?