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 23737C433FE for ; Wed, 23 Nov 2022 13:17:48 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E114010E552; Wed, 23 Nov 2022 13:17:46 +0000 (UTC) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8B47E10E551; Wed, 23 Nov 2022 13:17:44 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0D2BB61CAD; Wed, 23 Nov 2022 13:17:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3BFC433D6; Wed, 23 Nov 2022 13:17:36 +0000 (UTC) Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> Date: Wed, 23 Nov 2022 14:17:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Content-Language: en-US To: David Hildenbrand , linux-kernel@vger.kernel.org References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> From: Hans Verkuil In-Reply-To: <20221116102659.70287-14-david@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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, 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 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4ED7C3A59F for ; Wed, 23 Nov 2022 13:32:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238625AbiKWNcx (ORCPT ); Wed, 23 Nov 2022 08:32:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238874AbiKWNcT (ORCPT ); Wed, 23 Nov 2022 08:32:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6230E12D28; Wed, 23 Nov 2022 05:17:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1F0B9B81F24; Wed, 23 Nov 2022 13:17:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3BFC433D6; Wed, 23 Nov 2022 13:17:36 +0000 (UTC) Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> Date: Wed, 23 Nov 2022 14:17:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Content-Language: en-US To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Linus Torvalds , Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Shuah Khan , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann , Christoph Hellwig , Alex Williamson , Mauro Carvalho Chehab References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> From: Hans Verkuil In-Reply-To: <20221116102659.70287-14-david@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; 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 58B8FC433FE for ; Wed, 23 Nov 2022 13:18:24 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4NHMBk1bqcz3f58 for ; Thu, 24 Nov 2022 00:18:22 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=srs0=+b1z=3x=xs4all.nl=hverkuil@kernel.org; receiver=) Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4NHMB35k2Cz3bP1 for ; Thu, 24 Nov 2022 00:17:47 +1100 (AEDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0D2BB61CAD; Wed, 23 Nov 2022 13:17:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3BFC433D6; Wed, 23 Nov 2022 13:17:36 +0000 (UTC) Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> Date: Wed, 23 Nov 2022 14:17:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Content-Language: en-US To: David Hildenbrand , linux-kernel@vger.kernel.org References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> From: Hans Verkuil In-Reply-To: <20221116102659.70287-14-david@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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, 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, David Airlie , 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 , Lucas Stach , Linus Torvalds , Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; 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 1803DC433FE for ; Wed, 23 Nov 2022 13:31:58 +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:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZwnlPFFm7Ii5RLgilDpAq0ynEZZxw9g4MMjqUuTmorw=; b=jzaQFqnZljTb2q YbCjBxLiEeo3qRUgGxcH1UePZbNM8+vWw8dNCLhzkFv8G8+AgNO3JWgB80/iZzk0k9FnMr2jjTtQG 0/m7kWE8rUh6Sq9YF6/YQ0dCdkx53OYe5z0QJkbIaI8hAGf+G453Ld4VxODi3vD5HXHXqvkS0VkPH Z0xLeZaeWpfeietfXjVAN8wOHD/zpnKPnaZfXP4m5WzsHq2ItA1JPx//ZFMFCkxhFxkDH7Mkj0fC9 QcshfHwLSyoxVdNJ5GtY8vw1+ySLZmqXzxycEmIIO6wZS5sgKc5/sNLJkVyVeG0oJSaJRQ1U9tMzJ ubRmtA6M0/v/HsVCkPSA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxppS-00HFTo-JS; Wed, 23 Nov 2022 13:30:18 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxpom-00HEmk-8b; Wed, 23 Nov 2022 13:29:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:Content-Type :In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID: Sender:Reply-To:Content-ID:Content-Description; bh=JzBAHGiYGonhKt624puQu+Q7dXE0IseQBohJYpzV3iw=; b=Sb/6Zyho4citOBJKT9yx1TRh6z aYXOZcPE/OaPjdrDsad9Zl6v+CelP/dHX8ivDwborFfFtbPhKBFN2aaRe2VHSbxfy7oJZnGU/Vl1o sHCIRlhC5MIkAaxvDQiyzSpgYiT0zbohqZfo4udtiiE8NbFVrvwyqXdLTDfESm80DsLRkg7ID+0av 5GfIUnwmxQJe447KlFVM+E5sUTNyC7a+ENFQXLPzNYDUL4WVRmAjkQhuB4l//eFWVkWCB9pcJ8lEs cKekjp3ExXCkI67KGAGjn55QJw5CqLi1HDByAbTdgeCVpgdweYu0BPIfiNJj9rvG0WSnLMRpxxMB1 J/axFdvw==; Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxpdL-003n18-Vt; Wed, 23 Nov 2022 13:17:50 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0D2BB61CAD; Wed, 23 Nov 2022 13:17:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3BFC433D6; Wed, 23 Nov 2022 13:17:36 +0000 (UTC) Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> Date: Wed, 23 Nov 2022 14:17:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Content-Language: en-US To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Linus Torvalds , Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Shuah Khan , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann , Christoph Hellwig , Alex Williamson , Mauro Carvalho Chehab References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> From: Hans Verkuil In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221123_131748_447096_2EFF75BA X-CRM114-Status: GOOD ( 20.93 ) 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 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; _______________________________________________ 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 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 34225C433FE for ; Wed, 23 Nov 2022 13:30:33 +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:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=GKwIm+MQq4t01mB/a19WW32uSFfsFIMgPildQSfacQo=; b=synJljJuvhL33D Gx4ultaGlJZa3imLsq1dWV6wTmVHYzP0O2BPBsa5jxD4r0awmR1sL/Pb628ahElEjd3UnCsajXY0w x9BirIo15YCY5yLs1PT7RboKRx0tMr3DM1tYLHo6Eo+kK8HnSB2QD15uMUv8IS24j2EGorptGULfy HsX5ag6tt4rmmfF3Xg7blDa35VZcQVYjwLl2kH9dd6ajMb539+uSaQNa9M7j9rszJgMhNjoKlBpB3 Sqx0XjELBCg9tMJmc3eQpWtPp6CJdrvZIkTQctJkSsZUiKX2KCAjCQSxHGmKPpPQuc2UuHyef89iy kHdW/utCbPWO8OytZV4w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxppg-00HFci-Ax; Wed, 23 Nov 2022 13:30:32 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxpom-00HEmk-8b; Wed, 23 Nov 2022 13:29:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:Content-Type :In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID: Sender:Reply-To:Content-ID:Content-Description; bh=JzBAHGiYGonhKt624puQu+Q7dXE0IseQBohJYpzV3iw=; b=Sb/6Zyho4citOBJKT9yx1TRh6z aYXOZcPE/OaPjdrDsad9Zl6v+CelP/dHX8ivDwborFfFtbPhKBFN2aaRe2VHSbxfy7oJZnGU/Vl1o sHCIRlhC5MIkAaxvDQiyzSpgYiT0zbohqZfo4udtiiE8NbFVrvwyqXdLTDfESm80DsLRkg7ID+0av 5GfIUnwmxQJe447KlFVM+E5sUTNyC7a+ENFQXLPzNYDUL4WVRmAjkQhuB4l//eFWVkWCB9pcJ8lEs cKekjp3ExXCkI67KGAGjn55QJw5CqLi1HDByAbTdgeCVpgdweYu0BPIfiNJj9rvG0WSnLMRpxxMB1 J/axFdvw==; Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxpdL-003n18-Vt; Wed, 23 Nov 2022 13:17:50 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0D2BB61CAD; Wed, 23 Nov 2022 13:17:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3BFC433D6; Wed, 23 Nov 2022 13:17:36 +0000 (UTC) Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> Date: Wed, 23 Nov 2022 14:17:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Content-Language: en-US To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Linus Torvalds , Andrew Morton , Jason Gunthorpe , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit , Vlastimil Babka , Matthew Wilcox , Mike Kravetz , Muchun Song , Shuah Khan , Lucas Stach , David Airlie , Oded Gabbay , Arnd Bergmann , Christoph Hellwig , Alex Williamson , Mauro Carvalho Chehab References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> From: Hans Verkuil In-Reply-To: <20221116102659.70287-14-david@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221123_131748_447096_2EFF75BA X-CRM114-Status: GOOD ( 20.93 ) 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 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; _______________________________________________ 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: Hans Verkuil Date: Wed, 23 Nov 2022 13:17:35 +0000 Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Message-Id: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> 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 , linux-kernel@vger.kernel.org Cc: 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 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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; From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Verkuil Subject: Re: [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: remove FOLL_FORCE usage Date: Wed, 23 Nov 2022 14:17:35 +0100 Message-ID: <73481668-9c41-7d01-d328-bd137a57c0b3@xs4all.nl> References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-14-david@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Content-Language: en-US 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" To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: 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, David Airlie , 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 On 16/11/2022 11:26, 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 Acked-by: Hans Verkuil Looks good! Hans > --- > 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;