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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 70D0CC04EB8 for ; Sat, 8 Dec 2018 18:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3523A2083D for ; Sat, 8 Dec 2018 18:26:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="kmhyFYsN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3523A2083D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726298AbeLHS0P (ORCPT ); Sat, 8 Dec 2018 13:26:15 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48836 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726142AbeLHS0P (ORCPT ); Sat, 8 Dec 2018 13:26:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LBRTYd/n8sZthRzRMvHQ53RvvZe2kPi8PcMY/Qi5xBw=; b=kmhyFYsNyN3d/ly5PUn+Qsv6w mEtcQwA80JMWPgBdmQJUM13DGCCc5wJBwbXmUO8OqfefiVESbKff3A9LsBH0Ci69ljiEWjqgH7/oK kw+IYqrUQ5GOT7woyBT6ZeUwBZZf6RQvXjmYsWgf8EHQRzf85Kx9gCQdzJALVLBrvKTTUOwE5A3GG 7dqoIl4K6/W67pWFTe3ln3TGcs3O/5JtFB2bY4zP/UN+zTdofYldsuk562+uqthy5why7Yd8a/JZs Ph++M4vQYaf/RwUqy0/g7TmessSJ2l0k251wfKB9fAP0PQn7YQCc7CKG2qQAGRJoD3ruJNMazra56 z3A4dtYwQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVhIi-0007gY-Nv; Sat, 08 Dec 2018 18:26:04 +0000 Date: Sat, 8 Dec 2018 10:26:04 -0800 From: Christoph Hellwig To: Jerome Glisse Cc: Christoph Hellwig , Dan Williams , John Hubbard , Matthew Wilcox , John Hubbard , Andrew Morton , Linux MM , Jan Kara , tom@talpey.com, Al Viro , benve@cisco.com, Christopher Lameter , "Dalessandro, Dennis" , Doug Ledford , Jason Gunthorpe , Michal Hocko , Mike Marciniszyn , rcampbell@nvidia.com, Linux Kernel Mailing List , linux-fsdevel Subject: Re: [PATCH 1/2] mm: introduce put_user_page*(), placeholder versions Message-ID: <20181208182604.GA24564@infradead.org> References: <20181205011519.GV10377@bombadil.infradead.org> <20181205014441.GA3045@redhat.com> <59ca5c4b-fd5b-1fc6-f891-c7986d91908e@nvidia.com> <7b4733be-13d3-c790-ff1b-ac51b505e9a6@nvidia.com> <20181207191620.GD3293@redhat.com> <3c4d46c0-aced-f96f-1bf3-725d02f11b60@nvidia.com> <20181208163353.GA2952@redhat.com> <20181208164825.GA26154@infradead.org> <20181208174730.GB2952@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181208174730.GB2952@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 08, 2018 at 12:47:30PM -0500, Jerome Glisse wrote: > Most of the user of GUP are well behave (everything under driver/gpu and > so is mellanox driver and many other) ie they abide by mmu notifier > invalidation call backs. They are a handfull of device driver that thought > they could just do GUP and ignore the mmu notifier part and those are the > one being problematic. So to me it feels like bystander are be shot for no > good reasons. get_user_pages is used by every single direct I/O, and while the race windows in that case are small they very much exists.