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[212.51.149.33]) by smtp.gmail.com with ESMTPSA id g13-20020a50ec0d000000b0045b3853c4b7sm7352935edr.51.2022.11.16.02.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 02:48:58 -0800 (PST) Date: Wed, 16 Nov 2022 11:48:56 +0100 From: Daniel Vetter To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-ID: Mail-Followup-To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-Operating-System: Linux phenom 5.19.0-2-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 0DBC3C4332F for ; Wed, 16 Nov 2022 10:49:03 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 48C7910E08D; Wed, 16 Nov 2022 10:49:02 +0000 (UTC) Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by gabe.freedesktop.org (Postfix) with ESMTPS id C483710E08D for ; Wed, 16 Nov 2022 10:49:00 +0000 (UTC) Received: by mail-ej1-x636.google.com with SMTP id kt23so43092386ejc.7 for ; Wed, 16 Nov 2022 02:49:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=VJ17UkTNHUXDMc38lOye7y2paGd4FOYHBRYpe2vgelPuC55Z4g5rnX+xNi0NFRGTrN mdMUVKijrbkJJfn3y8Tm8vf3pLdF4omxIOM6UM8S6CVz2p3NrVUPvz4FNRN3RF3rQ/lN 9z9ibLXy5LDPJfO5cF7QIpPDKsW5E+659K7gg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=PsT/N/+O5poPpVwXC/mP6Go73w9ViruXWQv5SYrgCcusxCCvKD7fdoVSw2FlJtw/U5 oPcKEgPDbL6WNaADozztRQv47pH0tvzbBSUPbHKLLoVh+QT/zxxUy/beDv1yihkuTs3r 1WsreyUc0PrUGdBkFbdj3Xk6dVHwJue8nE3TZtIJzTp9UTrVA1OdGUDW01Lc14L/qh+d tUqynrvY3YuIuuLBejzO1xfJpniRsm1iJe0V34C8dHGOhHePSvm9UiVcnv3H5TpG8jd2 uptd7CHY47+Qf1zRLFG57+ha16WxrjmfwsRX6VLdpe+CwCJqqGgunNIbDziw319uxJ5+ y4LQ== X-Gm-Message-State: ANoB5pkj86rMSZ4OeUQ2Hr3fsUO6OwJ3durXZkVRAauEl6kPiDU4Xw5V 5WuvkjaRiuQDnlfnCcorJ/82ng== X-Google-Smtp-Source: AA0mqf6lc5lrEzUlEqYgu67h96R4r19JtBnDlqqKBl9ey0VuIf1EYIOTKVPSxvCTipQmxuaB88n35Q== X-Received: by 2002:a17:906:970e:b0:7ad:ccae:a30d with SMTP id k14-20020a170906970e00b007adccaea30dmr18079730ejx.704.1668595739329; Wed, 16 Nov 2022 02:48:59 -0800 (PST) Received: from phenom.ffwll.local (212-51-149-33.fiber7.init7.net. [212.51.149.33]) by smtp.gmail.com with ESMTPSA id g13-20020a50ec0d000000b0045b3853c4b7sm7352935edr.51.2022.11.16.02.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 02:48:58 -0800 (PST) Date: Wed, 16 Nov 2022 11:48:56 +0100 From: Daniel Vetter To: David Hildenbrand Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-ID: Mail-Followup-To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-Operating-System: Linux phenom 5.19.0-2-amd64 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-ia64@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , Vlastimil Babka , Greg Kroah-Hartman , Oded Gabbay , Linus Torvalds , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, Mike Kravetz Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0598C433FE for ; Wed, 16 Nov 2022 10:51:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5QEvBHXUL1m/oAeHq1ghZihijYN6O5ctefPLgOBJz9k=; b=Efjw5buXq8qJRr zCySfd4DLQnLHvhsXbB1Eq3dM7P+ZdbhlSSC7D1JAmtjqmYWJ+eBSGLEU1V5d93wdLCEZQQZc9GXP s1WK7rjFgwfFrjmy/i+ef5ZX7mQzJNqz4rz2Ap/AvU3CiMbHAyhlnfLc1IXnKAfW/2n26F4kq1fMp D0G5QYi6OmBuynXQHuuIzzzvKU6l1jA6UbLOMej14YxkdSGyIlI7m15tML2t/ZonFBlmAOfuUVP6O ajcm+3hlUkkQ8s5apOJ9MbTHLL1ntf4Vf7E7TVCq4Z7xz0EbpdZ4s2LG1eSoVhh8x8v3Q9Ubj1stg 9eUYDOghEKaR0EMKBMxA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovFz5-002RIx-U9; Wed, 16 Nov 2022 10:49:36 +0000 Received: from mail-ej1-x62e.google.com ([2a00:1450:4864:20::62e]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovFyc-002Qno-8E for linux-arm-kernel@lists.infradead.org; Wed, 16 Nov 2022 10:49:08 +0000 Received: by mail-ej1-x62e.google.com with SMTP id bj12so43006556ejb.13 for ; Wed, 16 Nov 2022 02:49:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=VJ17UkTNHUXDMc38lOye7y2paGd4FOYHBRYpe2vgelPuC55Z4g5rnX+xNi0NFRGTrN mdMUVKijrbkJJfn3y8Tm8vf3pLdF4omxIOM6UM8S6CVz2p3NrVUPvz4FNRN3RF3rQ/lN 9z9ibLXy5LDPJfO5cF7QIpPDKsW5E+659K7gg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=A+59xcpZcHByX18E+YMu+dZX8EoCwCnW/TywggfwU5g52y2RyBIh+PQ71ujnVa/Qj+ s457ePFzsuUliDQOB9me+cpSjt+KJLMs/HzStTtlj+zKu9h+poFxTfVOdArRjH5GYAWg IWy4ciTuIPnB3Vk0vHwuY02ApU0enytK4cPYIV5eBj3giVkmxt26IWYaU+0TC7vIMOHv UWHZiWyNlvDtCyIG4Yl2hapVnjVwFke0ax3eyFTgflwndQLvScXjGFtMSkuf+LudrcX/ UWjWRl7c/y/MpfNLTCfOBzz7q/vsptyK6s14kZX33CYEaB7nUr2/bZ+Xwd36Mo/mA1f0 v9IQ== X-Gm-Message-State: ANoB5pn9uofrbpn+Wo5mwpfSb/I09ldSBt2oqFVb5CAcwGba8xQ539/X /IaBiXp+LpUydjze4wyb9WiVNA== X-Google-Smtp-Source: AA0mqf6lc5lrEzUlEqYgu67h96R4r19JtBnDlqqKBl9ey0VuIf1EYIOTKVPSxvCTipQmxuaB88n35Q== X-Received: by 2002:a17:906:970e:b0:7ad:ccae:a30d with SMTP id k14-20020a170906970e00b007adccaea30dmr18079730ejx.704.1668595739329; Wed, 16 Nov 2022 02:48:59 -0800 (PST) Received: from phenom.ffwll.local (212-51-149-33.fiber7.init7.net. [212.51.149.33]) by smtp.gmail.com with ESMTPSA id g13-20020a50ec0d000000b0045b3853c4b7sm7352935edr.51.2022.11.16.02.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 02:48:58 -0800 (PST) Date: Wed, 16 Nov 2022 11:48:56 +0100 From: Daniel Vetter To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-ID: Mail-Followup-To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-Operating-System: Linux phenom 5.19.0-2-amd64 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221116_024906_332081_D2F26C33 X-CRM114-Status: GOOD ( 24.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- 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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF688C433FE for ; Wed, 16 Nov 2022 10:49:58 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4NC0Dj2zflz3f8C for ; Wed, 16 Nov 2022 21:49:57 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=ffwll.ch header.i=@ffwll.ch header.a=rsa-sha256 header.s=google header.b=VJ17UkTN; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=ffwll.ch (client-ip=2a00:1450:4864:20::630; helo=mail-ej1-x630.google.com; envelope-from=daniel@ffwll.ch; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; secure) header.d=ffwll.ch header.i=@ffwll.ch header.a=rsa-sha256 header.s=google header.b=VJ17UkTN; dkim-atps=neutral Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4NC0Ch4Z4Hz2xml for ; Wed, 16 Nov 2022 21:49:03 +1100 (AEDT) Received: by mail-ej1-x630.google.com with SMTP id gv23so10355054ejb.3 for ; Wed, 16 Nov 2022 02:49:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=VJ17UkTNHUXDMc38lOye7y2paGd4FOYHBRYpe2vgelPuC55Z4g5rnX+xNi0NFRGTrN mdMUVKijrbkJJfn3y8Tm8vf3pLdF4omxIOM6UM8S6CVz2p3NrVUPvz4FNRN3RF3rQ/lN 9z9ibLXy5LDPJfO5cF7QIpPDKsW5E+659K7gg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=2gouWEQ5zS+YCg551IQygwnK5fTDzOnzOalg+tQtprfg7t7aCxV7RDt59qQODcxljA twY1of+ec+3fxZ8rELeq+En0izM8cOREmV+CJxecfBKnZkcLwxzPpI9EjCB6EIQ7GdhI LxiBQuV54ZQN5Pe4wr719VSG01HgYQnqfoWgN6b4vhsK96Tg0LD5K7P5No8hzbJldVHL 7M+RUSKjZmHhVh4TEWVmzxpBbf8+ZdmVNTF408Mi+VN5MrSoM9rJ1a6B5tESJ50jzaL/ YGyko9J6dKwRrdWsbbnK6mOwmPmY/rlkqbq0+oNyaqEK+6opF6yO8wCt9lsxW2wtb8Hz 2xmw== X-Gm-Message-State: ANoB5pkyLhexCQcIVzxxTroMIq0wx8UzCrhX2niNAQEh60qofc7YE0cx rPW6dQJ+3lVGx0CABO6wLJ0nEg== X-Google-Smtp-Source: AA0mqf6lc5lrEzUlEqYgu67h96R4r19JtBnDlqqKBl9ey0VuIf1EYIOTKVPSxvCTipQmxuaB88n35Q== X-Received: by 2002:a17:906:970e:b0:7ad:ccae:a30d with SMTP id k14-20020a170906970e00b007adccaea30dmr18079730ejx.704.1668595739329; Wed, 16 Nov 2022 02:48:59 -0800 (PST) Received: from phenom.ffwll.local (212-51-149-33.fiber7.init7.net. [212.51.149.33]) by smtp.gmail.com with ESMTPSA id g13-20020a50ec0d000000b0045b3853c4b7sm7352935edr.51.2022.11.16.02.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 02:48:58 -0800 (PST) Date: Wed, 16 Nov 2022 11:48:56 +0100 From: Daniel Vetter To: David Hildenbrand Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-ID: Mail-Followup-To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-Operating-System: Linux phenom 5.19.0-2-amd64 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , Vlastimil Babka , Greg Kroah-Hartman , Oded Gabbay , Linus Torvalds , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A127C433FE for ; Wed, 16 Nov 2022 10:49:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=INWIfUHFRbl90xzhr0CHQ4JiGdZqRbHtKdBLkiWqp60=; b=CG8b/haI9QQOsC T2vKniX3Lay+rYlckATJ3SrS4Sc6KrCyzrjQkO2D8Z3570Jo8OrF3PiVFMmCJNCcC/YW14EskNhLs 0TgZzH9ohGc5L5opTMgLs9/pod5/C7iu1z7gCqiiHvoUqZF2wNZ20ROVvCF83qC9uuIKign062hxC diYZRqLG1nDp4Ceyu6xh65f/00iX6XRekHrvCh9FK6dtT4pw1tYh29KZXfPwgmHFR7unM2uOkNagv PFG8vAoGAmv5yPE0WpvWaOjDQcJBIyle7S8Pi/hl+WQiWIdWEEfgQGAA8hh47CJDNnDDkxZEfl8JB ET7Mzm55Xd3m7eYZhr7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovFz2-002RFk-4U; Wed, 16 Nov 2022 10:49:32 +0000 Received: from mail-ej1-x632.google.com ([2a00:1450:4864:20::632]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovFyc-002Qnp-89 for linux-um@lists.infradead.org; Wed, 16 Nov 2022 10:49:08 +0000 Received: by mail-ej1-x632.google.com with SMTP id n20so22495990ejh.0 for ; Wed, 16 Nov 2022 02:49:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=VJ17UkTNHUXDMc38lOye7y2paGd4FOYHBRYpe2vgelPuC55Z4g5rnX+xNi0NFRGTrN mdMUVKijrbkJJfn3y8Tm8vf3pLdF4omxIOM6UM8S6CVz2p3NrVUPvz4FNRN3RF3rQ/lN 9z9ibLXy5LDPJfO5cF7QIpPDKsW5E+659K7gg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=4SLlxnXp6FfBaRtx/f67XOSbEyad3Ah52pVodpyrqYh0rgGvZ7tCXpVVjtCtoomPyq B5ZedsO/ioQMH5ZDt9TIwnaUKRCNXuy9FSszi/sZEFWWqWGBQVdN4nuCmS+aDjMSTCD7 YZzBhNr5vg6d6Y9CQa+3hXo3fvkoEftvOAPdX8c2dUouSqf3uR+8/284/TFk85ITQYvL 3FzRnm+etuRBWOtDP945IQ9WpEIUtDu4uhck3TDDoU19XoQqhY+WzHt6ds7unSTKec8L 0c/lnIboHoAubpQrRUPxoyz9luV9kNY5aF6Hf4Fp8+9H58/7KB450VGBwAOFriLtwVD1 vu3A== X-Gm-Message-State: ANoB5pmPLDdagvw5mA+WXRiiI0G8g0a18fRqCuvIxs/YmED5P4mYU3un 3YkOG3uvEOEeiwZVXbl44tiqSQ== X-Google-Smtp-Source: AA0mqf6lc5lrEzUlEqYgu67h96R4r19JtBnDlqqKBl9ey0VuIf1EYIOTKVPSxvCTipQmxuaB88n35Q== X-Received: by 2002:a17:906:970e:b0:7ad:ccae:a30d with SMTP id k14-20020a170906970e00b007adccaea30dmr18079730ejx.704.1668595739329; Wed, 16 Nov 2022 02:48:59 -0800 (PST) Received: from phenom.ffwll.local (212-51-149-33.fiber7.init7.net. [212.51.149.33]) by smtp.gmail.com with ESMTPSA id g13-20020a50ec0d000000b0045b3853c4b7sm7352935edr.51.2022.11.16.02.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 02:48:58 -0800 (PST) Date: Wed, 16 Nov 2022 11:48:56 +0100 From: Daniel Vetter To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-ID: Mail-Followup-To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-Operating-System: Linux phenom 5.19.0-2-amd64 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221116_024906_341590_2E9EE046 X-CRM114-Status: GOOD ( 23.01 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Date: Wed, 16 Nov 2022 10:48:56 +0000 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-Id: List-Id: References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> In-Reply-To: <20221116102659.70287-14-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Greg Kroah-Hartman , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Oded Gabbay , linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , Mike Kravetz On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL = dma->pages) > return -ENOMEM; > > - if (rw = READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Date: Wed, 16 Nov 2022 11:48:56 +0100 Message-ID: References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=OSCwvxDUrivspPm0mWYSEKkrMB19obOv39RUwyA0PH0=; b=VJ17UkTNHUXDMc38lOye7y2paGd4FOYHBRYpe2vgelPuC55Z4g5rnX+xNi0NFRGTrN mdMUVKijrbkJJfn3y8Tm8vf3pLdF4omxIOM6UM8S6CVz2p3NrVUPvz4FNRN3RF3rQ/lN 9z9ibLXy5LDPJfO5cF7QIpPDKsW5E+659K7gg= Content-Disposition: inline In-Reply-To: <20221116102659.70287-14-david@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane-mx.org@lists.ozlabs.org Sender: "Linuxppc-dev" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: David Hildenbrand Cc: linux-ia64@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, Nadav Amit , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , Andrea Arcangeli , linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , Matthew Wilcox , Christoph Hellwig , Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, Arnd Bergmann , John Hubbard , linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, Alex Williamson , Peter Xu , Muchun Song , e.com, , Mauro Carvalho Chehab , Vlastimil Babka , Greg On Wed, Nov 16, 2022 at 11:26:52AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand I looked at this a while ago when going through some of the follow_pfn stuff, so Reviewed-by: Daniel Vetter > --- > drivers/media/v4l2-core/videobuf-dma-sg.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c > index f75e5eedeee0..234e9f647c96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-sg.c > +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c > @@ -151,17 +151,16 @@ static void videobuf_dma_init(struct videobuf_dmabuf *dma) > static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > int direction, unsigned long data, unsigned long size) > { > + unsigned int gup_flags = FOLL_LONGTERM; > unsigned long first, last; > - int err, rw = 0; > - unsigned int flags = FOLL_FORCE; > + int err; > > dma->direction = direction; > switch (dma->direction) { > case DMA_FROM_DEVICE: > - rw = READ; > + gup_flags |= FOLL_WRITE; > break; > case DMA_TO_DEVICE: > - rw = WRITE; > break; > default: > BUG(); > @@ -177,14 +176,11 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, > if (NULL == dma->pages) > return -ENOMEM; > > - if (rw == READ) > - flags |= FOLL_WRITE; > - > dprintk(1, "init user [0x%lx+0x%lx => %lu pages]\n", > data, size, dma->nr_pages); > > - err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, > - flags | FOLL_LONGTERM, dma->pages, NULL); > + err = pin_user_pages(data & PAGE_MASK, dma->nr_pages, gup_flags, > + dma->pages, NULL); > > if (err != dma->nr_pages) { > dma->nr_pages = (err >= 0) ? err : 0; > -- > 2.38.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch