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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 778B6C46466 for ; Mon, 5 Oct 2020 18:37:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 125D6212CC for ; Mon, 5 Oct 2020 18:37:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="eN0A5e22" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 125D6212CC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4D9AC900017; Mon, 5 Oct 2020 14:37:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 48AB190000C; Mon, 5 Oct 2020 14:37:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 35244900017; Mon, 5 Oct 2020 14:37:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id 03F3D90000C for ; Mon, 5 Oct 2020 14:37:07 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 95AA1180AD801 for ; Mon, 5 Oct 2020 18:37:07 +0000 (UTC) X-FDA: 77338728894.15.pie28_62159c6271c0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin15.hostedemail.com (Postfix) with ESMTP id 6AE931814B0C7 for ; Mon, 5 Oct 2020 18:37:07 +0000 (UTC) X-HE-Tag: pie28_62159c6271c0 X-Filterd-Recvd-Size: 5543 Received: from mail-qk1-f193.google.com (mail-qk1-f193.google.com [209.85.222.193]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Mon, 5 Oct 2020 18:37:06 +0000 (UTC) Received: by mail-qk1-f193.google.com with SMTP id q63so13113176qkf.3 for ; Mon, 05 Oct 2020 11:37:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=u3J6AKxubCllq2Ls7jrnfIH9wJzGGs2W2keKyCoQZ+g=; b=eN0A5e22fGI+9D7L6SnBKQWwDKTGT6A2sP8lBv5ySLpbcmf3PfBbHF2iMutUZFpPlh w3htf6sVN26BUBiEQwMJl/9SKhV9wenSbaw0Ngblhz/K+BWlCmn4PDdP71seEGgKDhJn EI05euYmWOHnzyl0KxDqo544jd74Rcgi6WhiyS+2C4ZGYV3/oydMjKLmzfnF7Key+1Xw Ma93hb6+RGildfaRFvy5Y2VJL2Rc7rtFtIO56w2vrpHgDx7Atids/vghgSE0VBGyimgQ uvvUuJzw4EU0nPQywaCcIxKzFxDpSAFENlo/i0BFbsFA+61tMShgDjlQrWvTN2JFip4Q P6dA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=u3J6AKxubCllq2Ls7jrnfIH9wJzGGs2W2keKyCoQZ+g=; b=QIkAkr8UqZTOKvREyHyedDUp5SPfGIA4thbOtWfO3FgtimSOCO09tIxjGK1jdMC9qb 3a2cyLZi54B4sxJAC6MiVvlCCn/M/BsIMjOFefr/Q7EB5FFD+cjZhXt3OpHO99nAMFbS gH55nwBmjCd0hyfKibA1Jfmj/m3WUnaKGqt+DUEbQLSQf0DhAheWlfayOP5G6nqdUp0C lDHs4gn78KS7pFy+3hkGlFy1cvypgM7fMVAkdd1onYS8RvuJeKLZqD6UYMVePSODqWFB eJ8TNZscKYXwm8zF90ERmSYxgifP+VWosFf+oqXqhgtyMk6n11s4KDxwmQlcAjykvIDj B+WA== X-Gm-Message-State: AOAM532Jh/aDY2MIoUJZTVKkW7n+EtJfmQZ+E69sCdgf6CPADYZ9t8qY g9tQs1YECkwwx0XLzuTmWEfHOg== X-Google-Smtp-Source: ABdhPJyiYyJ6QGbYxkNE1y766DNr8LNQurJWOP4L2+ndFQuLZsD7R3NQL8Vs0Mi8tA3m1+v8usWh/w== X-Received: by 2002:a05:620a:1266:: with SMTP id b6mr1396650qkl.371.1601923026236; Mon, 05 Oct 2020 11:37:06 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id d21sm387410qtp.97.2020.10.05.11.37.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Oct 2020 11:37:05 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kPVM8-0008jm-C7; Mon, 05 Oct 2020 15:37:04 -0300 Date: Mon, 5 Oct 2020 15:37:04 -0300 From: Jason Gunthorpe To: Daniel Vetter Cc: DRI Development , LKML , Daniel Vetter , Andrew Morton , John Hubbard , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Jan Kara , Dan Williams , Linux MM , Linux ARM , Pawel Osciak , Marek Szyprowski , Kyungmin Park , Tomasz Figa , Inki Dae , Joonyoung Shim , Seung-Woo Kim , linux-samsung-soc , "open list:DMA BUFFER SHARING FRAMEWORK" , Oded Gabbay Subject: Re: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM Message-ID: <20201005183704.GC5177@ziepe.ca> References: <20201002175303.390363-1-daniel.vetter@ffwll.ch> <20201002175303.390363-2-daniel.vetter@ffwll.ch> <20201002180603.GL9916@ziepe.ca> <20201002233118.GM9916@ziepe.ca> <20201004125059.GP9916@ziepe.ca> <20201005172854.GA5177@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Mon, Oct 05, 2020 at 08:16:33PM +0200, Daniel Vetter wrote: > > kvm is some similar hack added for P2P DMA, see commit > > add6a0cd1c5ba51b201e1361b05a5df817083618. It might be protected by notifiers.. > > Yeah my thinking is that kvm (and I think also vfio, also seems to > have mmu notifier nearby) are ok because of the mmu notiifer. Assuming > that one works correctly. vfio doesn't have a notifier, Alex was looking to add a vfio private scheme in the vma->private_data: https://lore.kernel.org/kvm/159017449210.18853.15037950701494323009.stgit@gimli.home/ Guess it never happened. > > So, the answer really is that s390 and media need fixing, and this API > > should go away (or become kvm specific) > > I'm still not clear how you want fo fix this, since your vma->dma_buf > idea is kinda a decade long plan and so just not going to happen: Well, it doesn't mean we have to change every part of dma_buf to participate in this. Just the bits media cares about. Or maybe it is some higher level varient on top of dma_buf. Or don't use dma_buf for this, add a new object that just provides refcounts and P2P DMA connection for IO pfn ranges.. Jason