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,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 74388C4363D for ; Wed, 7 Oct 2020 12:58:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E882B2083B for ; Wed, 7 Oct 2020 12:58:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="HLP5cVy/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728356AbgJGM6q (ORCPT ); Wed, 7 Oct 2020 08:58:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728177AbgJGM6p (ORCPT ); Wed, 7 Oct 2020 08:58:45 -0400 Received: from mail-ot1-x341.google.com (mail-ot1-x341.google.com [IPv6:2607:f8b0:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C537C061755 for ; Wed, 7 Oct 2020 05:58:45 -0700 (PDT) Received: by mail-ot1-x341.google.com with SMTP id f37so2026992otf.12 for ; Wed, 07 Oct 2020 05:58:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RqJhQ9wl4HnfFJba5qafgVA83HvKuODOv14/VuzQKBc=; b=HLP5cVy/+ivPAr8S6VW2DODWQvroNZFg7BttjeOcbezz6CNNniUIHSIARYKF8Ijk1T rmy9z7yE9flAapP4YSBu9HIymzY2iBki4HzaALq9rM2UBFkXQlEaW3TvVZzqH2LSayDe 1rPcp7GgFX99YVk0vI8HYbxifKX0pBDMeSfv0= 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=RqJhQ9wl4HnfFJba5qafgVA83HvKuODOv14/VuzQKBc=; b=emuGd80gKgVwTUv6kxN+iq1XWj4rb8Q5jt3EtuZtFWgMvW8Yy+08Gyvki7m+W1i+/1 S9U6qtUlglzgEJXQfts0Xhu505lB75pm9ToPdaavWYdnzZrLtj6/ISyl+UvCk385qC1l 4UyH58YbzLSwoSnBOeE/QCoNd1Fe+nJ51mun+X2sIDimgMOUQyv1nli1Rg9tFZSG2t+h +m3ND/aSRAPsfHfRtNjRV63IEYkwQ/MpZlVJxAOeJ20hk3l+zqjsgocvvXRYi2e7f4ak tGMN6RDU3s8bpimFFgfWShpx6GzeMZbzt1UY87xEinxS+KAs6CBgrdP2yZ/HN9DlQ6Al BBXA== X-Gm-Message-State: AOAM530qQLnzUwQPlXpCU04aIJ33OKPuQa6ALgkDrbadRpEg/D8+b4sO XZAPGaTKalRPbrDfoCDdcpHwkfPbvBvA3IpHuCDv1A== X-Google-Smtp-Source: ABdhPJwvOqDF0PtNvyjRy9NUPdpqckHeo5Pb4aBKzEFyLCyusu6A+MJ6CRQQIQu70npKdaR3NW8xVD0BDZv4+5HBzkA= X-Received: by 2002:a05:6830:1e56:: with SMTP id e22mr1696603otj.303.1602075524433; Wed, 07 Oct 2020 05:58:44 -0700 (PDT) MIME-Version: 1.0 References: <20201002175303.390363-1-daniel.vetter@ffwll.ch> <20201002175303.390363-2-daniel.vetter@ffwll.ch> <20201002180603.GL9916@ziepe.ca> <20201002233118.GM9916@ziepe.ca> <725819e9-4f07-3f04-08f8-b6180406b339@samsung.com> <20201007124409.GN5177@ziepe.ca> In-Reply-To: From: Daniel Vetter Date: Wed, 7 Oct 2020 14:58:33 +0200 Message-ID: Subject: Re: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM To: Tomasz Figa Cc: Jason Gunthorpe , Marek Szyprowski , DRI Development , LKML , Daniel Vetter , Andrew Morton , John Hubbard , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jan Kara , Dan Williams , Linux MM , Linux ARM , Pawel Osciak , Kyungmin Park , Inki Dae , Joonyoung Shim , Seung-Woo Kim , linux-samsung-soc , "open list:DMA BUFFER SHARING FRAMEWORK" , Oded Gabbay Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 7, 2020 at 2:48 PM Tomasz Figa wrote: > > On Wed, Oct 7, 2020 at 2:44 PM Jason Gunthorpe wrote: > > > > On Wed, Oct 07, 2020 at 02:33:56PM +0200, Marek Szyprowski wrote: > > > Well, it was in vb2_get_vma() function, but now I see that it has been > > > lost in fb639eb39154 and 6690c8c78c74 some time ago... > > > > There is no guarentee that holding a get on the file says anthing > > about the VMA. This needed to check that the file was some special > > kind of file that promised the VMA layout and file lifetime are > > connected. > > > > Also, cloning a VMA outside the mm world is just really bad. That > > would screw up many assumptions the drivers make. > > > > If it is all obsolete I say we hide it behind a default n config > > symbol and taint the kernel if anything uses it. > > > > Add a big comment above the follow_pfn to warn others away from this > > code. > > Sadly it's just verbally declared as deprecated and not formally noted > anyway. There are a lot of userspace applications relying on user > pointer support. userptr can stay, it's the userptr abuse for zerocpy buffer sharing which doesn't work anymore. At least without major surgery (you'd need an mmu notifier to zap mappings and recreate them, and that pretty much breaks the v4l model of preallocating all buffers to make sure we never underflow the buffer queue). And static mappings are not coming back I think, we'll go ever more into the direction of dynamic mappings and moving stuff around as needed. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch 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=-4.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 8DADDC4363D for ; Wed, 7 Oct 2020 13:00:21 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 D2FBA20789 for ; 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Wed, 07 Oct 2020 05:58:44 -0700 (PDT) MIME-Version: 1.0 References: <20201002175303.390363-1-daniel.vetter@ffwll.ch> <20201002175303.390363-2-daniel.vetter@ffwll.ch> <20201002180603.GL9916@ziepe.ca> <20201002233118.GM9916@ziepe.ca> <725819e9-4f07-3f04-08f8-b6180406b339@samsung.com> <20201007124409.GN5177@ziepe.ca> In-Reply-To: From: Daniel Vetter Date: Wed, 7 Oct 2020 14:58:33 +0200 Message-ID: Subject: Re: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM To: Tomasz Figa X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201007_085846_726287_C0FAEAFB X-CRM114-Status: GOOD ( 22.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Oded Gabbay , Inki Dae , linux-samsung-soc , Jan Kara , Joonyoung Shim , Pawel Osciak , Linux MM , John Hubbard , Seung-Woo Kim , LKML , DRI Development , Kyungmin Park , Jason Gunthorpe , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Daniel Vetter , Andrew Morton , "open list:DMA BUFFER SHARING FRAMEWORK" , Dan Williams , Linux ARM , Marek Szyprowski Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Oct 7, 2020 at 2:48 PM Tomasz Figa wrote: > > On Wed, Oct 7, 2020 at 2:44 PM Jason Gunthorpe wrote: > > > > On Wed, Oct 07, 2020 at 02:33:56PM +0200, Marek Szyprowski wrote: > > > Well, it was in vb2_get_vma() function, but now I see that it has been > > > lost in fb639eb39154 and 6690c8c78c74 some time ago... > > > > There is no guarentee that holding a get on the file says anthing > > about the VMA. This needed to check that the file was some special > > kind of file that promised the VMA layout and file lifetime are > > connected. > > > > Also, cloning a VMA outside the mm world is just really bad. That > > would screw up many assumptions the drivers make. > > > > If it is all obsolete I say we hide it behind a default n config > > symbol and taint the kernel if anything uses it. > > > > Add a big comment above the follow_pfn to warn others away from this > > code. > > Sadly it's just verbally declared as deprecated and not formally noted > anyway. There are a lot of userspace applications relying on user > pointer support. userptr can stay, it's the userptr abuse for zerocpy buffer sharing which doesn't work anymore. At least without major surgery (you'd need an mmu notifier to zap mappings and recreate them, and that pretty much breaks the v4l model of preallocating all buffers to make sure we never underflow the buffer queue). And static mappings are not coming back I think, we'll go ever more into the direction of dynamic mappings and moving stuff around as needed. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-3.5 required=3.0 tests=BAYES_00,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 EBB75C41604 for ; Wed, 7 Oct 2020 12:58:47 +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 BFB0A2080A for ; Wed, 7 Oct 2020 12:58:46 +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="HLP5cVy/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFB0A2080A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CCE296E8D5; Wed, 7 Oct 2020 12:58:45 +0000 (UTC) Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2A2016E8D5 for ; Wed, 7 Oct 2020 12:58:45 +0000 (UTC) Received: by mail-ot1-x344.google.com with SMTP id 60so2095817otw.3 for ; Wed, 07 Oct 2020 05:58:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RqJhQ9wl4HnfFJba5qafgVA83HvKuODOv14/VuzQKBc=; b=HLP5cVy/+ivPAr8S6VW2DODWQvroNZFg7BttjeOcbezz6CNNniUIHSIARYKF8Ijk1T rmy9z7yE9flAapP4YSBu9HIymzY2iBki4HzaALq9rM2UBFkXQlEaW3TvVZzqH2LSayDe 1rPcp7GgFX99YVk0vI8HYbxifKX0pBDMeSfv0= 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=RqJhQ9wl4HnfFJba5qafgVA83HvKuODOv14/VuzQKBc=; b=GsN1JJjtwXdZsah40uiyiZNQ41QPCQzh3t58oDNjJQE/DTlT2NXV5TJHhltlsZrpkl cyj948zoiLcmBzCam5Vu6UH1clPwydrNl455scgekJBug0p5WADC8yt9raXoJJAwdAyS m61gGrDq9s9XVOWNZbZev2fjo6m8SWAUO6fS53xCmPqs8JcPzeY5bUGqP0Y25RKV6vXV T4V3m6XffSw5dD01b/TNRGVWWvMi47ZL96UiqYfQ4/tYQISMA7nx/DJDiY3W9xBGV90a SCD+vY+LRWpw4L3N1mWSx2vb+DQgO0AdvEJq82AAOEimcRQ3zG5Ozki7A/Fjr4+miohz rMCA== X-Gm-Message-State: AOAM5336R/aJv32TgOGczEOem/+7J+6cN8SVNL3eVIbayrgf7GVv1dNW /MPx+qUi8nhMpWo9QQeF+FFOaMx/2Q3GQu1zwvYFhA== X-Google-Smtp-Source: ABdhPJwvOqDF0PtNvyjRy9NUPdpqckHeo5Pb4aBKzEFyLCyusu6A+MJ6CRQQIQu70npKdaR3NW8xVD0BDZv4+5HBzkA= X-Received: by 2002:a05:6830:1e56:: with SMTP id e22mr1696603otj.303.1602075524433; Wed, 07 Oct 2020 05:58:44 -0700 (PDT) MIME-Version: 1.0 References: <20201002175303.390363-1-daniel.vetter@ffwll.ch> <20201002175303.390363-2-daniel.vetter@ffwll.ch> <20201002180603.GL9916@ziepe.ca> <20201002233118.GM9916@ziepe.ca> <725819e9-4f07-3f04-08f8-b6180406b339@samsung.com> <20201007124409.GN5177@ziepe.ca> In-Reply-To: From: Daniel Vetter Date: Wed, 7 Oct 2020 14:58:33 +0200 Message-ID: Subject: Re: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM To: Tomasz Figa X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-samsung-soc , Jan Kara , Joonyoung Shim , Pawel Osciak , Linux MM , John Hubbard , Seung-Woo Kim , LKML , DRI Development , Kyungmin Park , Jason Gunthorpe , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Daniel Vetter , Andrew Morton , "open list:DMA BUFFER SHARING FRAMEWORK" , Dan Williams , Linux ARM , Marek Szyprowski Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Oct 7, 2020 at 2:48 PM Tomasz Figa wrote: > > On Wed, Oct 7, 2020 at 2:44 PM Jason Gunthorpe wrote: > > > > On Wed, Oct 07, 2020 at 02:33:56PM +0200, Marek Szyprowski wrote: > > > Well, it was in vb2_get_vma() function, but now I see that it has been > > > lost in fb639eb39154 and 6690c8c78c74 some time ago... > > > > There is no guarentee that holding a get on the file says anthing > > about the VMA. This needed to check that the file was some special > > kind of file that promised the VMA layout and file lifetime are > > connected. > > > > Also, cloning a VMA outside the mm world is just really bad. That > > would screw up many assumptions the drivers make. > > > > If it is all obsolete I say we hide it behind a default n config > > symbol and taint the kernel if anything uses it. > > > > Add a big comment above the follow_pfn to warn others away from this > > code. > > Sadly it's just verbally declared as deprecated and not formally noted > anyway. There are a lot of userspace applications relying on user > pointer support. userptr can stay, it's the userptr abuse for zerocpy buffer sharing which doesn't work anymore. At least without major surgery (you'd need an mmu notifier to zap mappings and recreate them, and that pretty much breaks the v4l model of preallocating all buffers to make sure we never underflow the buffer queue). And static mappings are not coming back I think, we'll go ever more into the direction of dynamic mappings and moving stuff around as needed. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel