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=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 425DEC433DF for ; Thu, 18 Jun 2020 14:42:42 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C034B20773 for ; Thu, 18 Jun 2020 14:42:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="Yv00WEyi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C034B20773 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 581126E3FE; Thu, 18 Jun 2020 14:42:41 +0000 (UTC) Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by gabe.freedesktop.org (Postfix) with ESMTPS id C05A86E3FE for ; Thu, 18 Jun 2020 14:42:40 +0000 (UTC) Received: by mail-wr1-x442.google.com with SMTP id p5so6312006wrw.9 for ; Thu, 18 Jun 2020 07:42:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=pdYzXGFouE6m4FSIkgrBziaqe3C5lzqdVFEvi65td6k=; b=Yv00WEyiSIg66gxJEUUQwcy2Tlc1E6Wc6zvKRDzYUlRDO6iCWLetHtRbnLoDvvQlXe zOvWWpAvNNuvZIWHgr0fKWDsU8iNkZKTU9Ci4Vt8EkYVQUyV00qvQSrVYglPeqw2m8hn YqvRGf3NKI0NMSmp82ufCgdaCILt0ba9vFJX0= 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 :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=pdYzXGFouE6m4FSIkgrBziaqe3C5lzqdVFEvi65td6k=; b=PVv3oap/VcXgSo7gW0pnOPfZmLicCRPDvaJ7cKQdwGnV/uIunHP9h1r8TRwmk7zB5a OX1Ld29tAE0LeLzdzDtgA6lLBoKyEJDFfxt6vDRgvz9Ysq6MXfymg6J2e0roPfJj/sfO Q/Ca094ZAuGwsw3Xl/OHWQhl1BtCu6KLRA3tMq2Ja8d34oafwCusXVXATmK9i/+49Be/ xn09CeOIOfUFQqHcUaqp/U4wvVk6j2O5cR26qbPReMaCLcWERsXPnbQcHdoHh+Gj1wK0 dLJjNMoRdixFNK2w1a166R5Sq0aTPb4Gx728tcskY/P6dxViOvHlVHLsusLRCH8Eko+H LeBA== X-Gm-Message-State: AOAM530UHJ7INvwQFjlRuoz2xmm9cuPmKb7o4G1LbiiRvjBMTFO7Fgno eQyza1/YinPq2NJ2HKXgZCvgPA== X-Google-Smtp-Source: ABdhPJxnVXjNFjlZjZjkcFFWafgkcwR6ZwnMtNAx31PJPXgT9P8/Pv/85bqfzuCJe/q/lkXd/e/Xbg== X-Received: by 2002:adf:cf0c:: with SMTP id o12mr4325124wrj.265.1592491359458; Thu, 18 Jun 2020 07:42:39 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id g25sm3649693wmh.18.2020.06.18.07.42.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Jun 2020 07:42:38 -0700 (PDT) Date: Thu, 18 Jun 2020 16:42:36 +0200 From: Daniel Vetter To: Jason Gunthorpe Message-ID: <20200618144236.GR20149@phenom.ffwll.local> Mail-Followup-To: Jason Gunthorpe , Thomas =?iso-8859-1?Q?Hellstr=F6m_=28Intel=29?= , DRI Development , linux-rdma , Intel Graphics Development , Maarten Lankhorst , LKML , amd-gfx list , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Thomas Hellstrom , Daniel Vetter , "open list:DMA BUFFER SHARING FRAMEWORK" , Christian =?iso-8859-1?Q?K=F6nig?= , Mika Kuoppala References: <20200604081224.863494-1-daniel.vetter@ffwll.ch> <20200604081224.863494-5-daniel.vetter@ffwll.ch> <20200611083430.GD20149@phenom.ffwll.local> <20200611141515.GW6578@ziepe.ca> <20200616120719.GL20149@phenom.ffwll.local> <20200616145312.GC6578@ziepe.ca> <20200617152940.GG6578@ziepe.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200617152940.GG6578@ziepe.ca> X-Operating-System: Linux phenom 5.6.0-1-amd64 Subject: Re: [Intel-gfx] [Linaro-mm-sig] [PATCH 04/18] dma-fence: prime lockdep annotations X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-rdma , LKML , DRI Development , Christian =?iso-8859-1?Q?K=F6nig?= , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Thomas Hellstrom , amd-gfx list , Daniel Vetter , Mika Kuoppala , Intel Graphics Development , "open list:DMA BUFFER SHARING FRAMEWORK" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Jun 17, 2020 at 12:29:40PM -0300, Jason Gunthorpe wrote: > On Wed, Jun 17, 2020 at 09:57:54AM +0200, Daniel Vetter wrote: > > > > At the very least I think there should be some big warning that > > > dma_fence in notifiers should be avoided. > > > > Yeah I'm working on documentation, and also the notifiers here > > hopefully make it clear it's massive pain. I think we could even make > > a hard rule that dma_fence in mmu notifier outside of drivers/gpu is a > > bug/misfeature. > > Yep! > > > Might be a good idea to add a MAINTAINERS entry with a K: regex > > pattern, so that you can catch such modifiers. We do already have such > > a pattern for dma-fence, to catch abuse. So if you want I could type > > up a documentation patch for this, get your and others acks and the > > dri-devel folks would enforce that the dma_fence_wait madness doesn't > > leak beyond drivers/gpu > > It seems like the best thing Just thought about where to best put this, and I think including it as another paragraph in the next round of this series makes the most sense. You'll get cc'ed for acking when that happens - might take a while since there's a lot of details here all over to sort out. -Daniel > > > Oded has agreed to remove the dma-fence usage, since they really don't > > need it (and all the baggage that comes with it), plain old completion > > is enough for their use. This use is also why I added the regex to > > MAINTAINERS, so that in the future we can catch people who try to use > > dma_fence because it looks cute and useful, and are completely > > oblivious to all the pain and headaches involved. > > This is good! > > Thanks, > Jason -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx