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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F4F2C4321E for ; Sun, 27 Nov 2022 10:35:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0429A6B0072; Sun, 27 Nov 2022 05:35:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F33496B0073; Sun, 27 Nov 2022 05:35:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DD44E6B0074; Sun, 27 Nov 2022 05:35:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id CDE0F6B0072 for ; Sun, 27 Nov 2022 05:35:15 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 9D3A81A092B for ; Sun, 27 Nov 2022 10:35:15 +0000 (UTC) X-FDA: 80178864990.24.B1BFE73 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf05.hostedemail.com (Postfix) with ESMTP id 028B310000F for ; Sun, 27 Nov 2022 10:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669545314; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=a/FKhEJUKr4Au5jEDV0nA39boCfv1uOAmeL78/XZzlw=; b=O27xJtPpaXX+WGWtRHYJetfQf0LitOuWyYASTvh9BOIc76OBbAvqAJoksVcyj8ihyyybuL K0BzXUXxU998BrnvTHmhdCmjqJ56s5MlltXbtXEOh8pcP8m9+etTCwEOVSMLMxVzLD+KhE 02JICc1N+vm9jg/GhumwHtE2HYBwStg= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-156-fmE22wZ6OLqaV18QCZ72cA-1; Sun, 27 Nov 2022 05:35:13 -0500 X-MC-Unique: fmE22wZ6OLqaV18QCZ72cA-1 Received: by mail-wr1-f70.google.com with SMTP id r23-20020adfa157000000b00241bcae980cso1294854wrr.7 for ; Sun, 27 Nov 2022 02:35:12 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:subject:organization:from :content-language:references:cc:to:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=a/FKhEJUKr4Au5jEDV0nA39boCfv1uOAmeL78/XZzlw=; b=Lb8qY7GNUYYoWqGZ4znXfDVGXbrnXACXVz5VRj1Vc89VTBr7bj2i/VC4tDDIyiPij/ Cz/WyEDRURylh/B/tEy5X8utmQkmVB0KA7eIXt+B3HCQFfh/FU1JrEjZKtjXjaP6pu7f r0rbPJxTOjnWiqsVG+H8hdFB4DBPW/ZurLS+08dZzS1CBl/pL9jUBHeH9tXHhxpRKQBz a0P2RMipsv5GrQ7ytojmHyNIVRtablh/O5Mk+jGdIgXT8KUH8hSaJtuWenHJQSUACPrD zyWZ+xUTPvQ9do4GT5dXeg/oIs+TH90pH6W0CReS74NPFsAM85jjbQFICpEIIInkDBM5 4jSA== X-Gm-Message-State: ANoB5pmsPg06IyzkZiJ90ILA8/s3kUqnMZs9aoQngRRLauojehQRHL2X 3pTY2URkzEc/jV07O8wG+3PoiP/ztzpRldSDwVztMBv6oJ2bmVIKtLeQxqCt/smOmx1NUQ4Qh6p eoK3dAHe0mTE= X-Received: by 2002:a05:600c:4e88:b0:3b5:477:1e80 with SMTP id f8-20020a05600c4e8800b003b504771e80mr34594864wmq.200.1669545312005; Sun, 27 Nov 2022 02:35:12 -0800 (PST) X-Google-Smtp-Source: AA0mqf44zTk6J1KBaqs1seffTqR2+v9TqwwPSmjBWI2JrtJKUPaYELfhGu32bDJHUXiVwBKDfUuj3g== X-Received: by 2002:a05:600c:4e88:b0:3b5:477:1e80 with SMTP id f8-20020a05600c4e8800b003b504771e80mr34594816wmq.200.1669545311706; Sun, 27 Nov 2022 02:35:11 -0800 (PST) Received: from ?IPV6:2003:cb:c724:dc00:5ea8:da59:8609:7da? (p200300cbc724dc005ea8da59860907da.dip0.t-ipconnect.de. [2003:cb:c724:dc00:5ea8:da59:8609:7da]) by smtp.gmail.com with ESMTPSA id u10-20020a05600c19ca00b003c5571c27a1sm14797024wmq.32.2022.11.27.02.35.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 27 Nov 2022 02:35:11 -0800 (PST) Message-ID: <81fb0fa3-2e06-b765-56ac-a7d981194e59@redhat.com> Date: Sun, 27 Nov 2022 11:35:09 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 To: linux-kernel@vger.kernel.org, Hans Verkuil , Andrew Morton 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 , 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 , Marek Szyprowski , Tomasz Figa , Mauro Carvalho Chehab References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-17-david@redhat.com> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH mm-unstable v1 16/20] mm/frame-vector: remove FOLL_FORCE usage In-Reply-To: <20221116102659.70287-17-david@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669545315; a=rsa-sha256; cv=none; b=uDcpKxmL5k0EQ1P3SQqn60EuK58ncNdq+aiXLjdFAEJqhK/YeOJcuHpQMOeMPXoIb+a1nA IZdXrqR8rUiulKO/Jsv78DcOfIjZKd9zXkroDqEZwv3Kca0oCpuIHXX7JP0CTdshP1KHfG Z5Ti7oYvmt5qTPpjv8iPI4NlN8/syqc= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=O27xJtPp; spf=pass (imf05.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669545315; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=a/FKhEJUKr4Au5jEDV0nA39boCfv1uOAmeL78/XZzlw=; b=WtUxPr4Vz0Nlj/k9Xtkr+FIUYPdF3jSkVopvXozp/SRg+qUOSmPfb7gVixPucTd20Mlx4X FYGTu7P74GgVI2L/psKyPqIeQf0GcLYGbFjMXTKqLv0rrMMyc2s/hlgsz/mtYmklC5EXjG K3ewPKAvVfVxOpcIeosRdgtBTZ4NtSE= X-Stat-Signature: 74owz7sgmmzghamo6o5p7mp4c7mrcq3y X-Rspamd-Queue-Id: 028B310000F X-Rspam-User: Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=O27xJtPp; spf=pass (imf05.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam10 X-HE-Tag: 1669545314-226913 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 16.11.22 11:26, David Hildenbrand wrote: > FOLL_FORCE is really only for ptrace access. According to commit > 707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are always > writable"), get_vaddr_frames() currently pins all pages writable as a > workaround for issues with read-only buffers. > > FOLL_FORCE, however, seems to be a legacy leftover as it predates > commit 707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are > always writable"). Let's just remove it. > > Once the read-only buffer issue has been resolved, FOLL_WRITE could > again be set depending on the DMA direction. > > Cc: Hans Verkuil > Cc: Marek Szyprowski > Cc: Tomasz Figa > Cc: Marek Szyprowski > Cc: Mauro Carvalho Chehab > Signed-off-by: David Hildenbrand > --- > drivers/media/common/videobuf2/frame_vector.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c > index 542dde9d2609..062e98148c53 100644 > --- a/drivers/media/common/videobuf2/frame_vector.c > +++ b/drivers/media/common/videobuf2/frame_vector.c > @@ -50,7 +50,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, > start = untagged_addr(start); > > ret = pin_user_pages_fast(start, nr_frames, > - FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM, > + FOLL_WRITE | FOLL_LONGTERM, > (struct page **)(vec->ptrs)); > if (ret > 0) { > vec->got_ref = true; Hi Andrew, see the discussion at [1] regarding a conflict and how to proceed with upstreaming. The conflict would be easy to resolve, however, also the patch description doesn't make sense anymore with [1]. On top of mm-unstable, reverting this patch and applying [1] gives me an updated patch: From 1e66c25f1467c1f1e5f275312f2c6df29308d4df Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 16 Nov 2022 11:26:55 +0100 Subject: [PATCH] mm/frame-vector: remove FOLL_FORCE usage 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. Reviewed-by: Daniel Vetter Acked-by: Hans Verkuil Cc: Hans Verkuil Cc: Marek Szyprowski Cc: Tomasz Figa Cc: Marek Szyprowski Cc: Mauro Carvalho Chehab Signed-off-by: David Hildenbrand --- drivers/media/common/videobuf2/frame_vector.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c index aad72640f055..8606fdacf5b8 100644 --- a/drivers/media/common/videobuf2/frame_vector.c +++ b/drivers/media/common/videobuf2/frame_vector.c @@ -41,7 +41,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, bool write, int ret_pin_user_pages_fast = 0; int ret = 0; int err; - unsigned int gup_flags = FOLL_FORCE | FOLL_LONGTERM; + unsigned int gup_flags = FOLL_LONGTERM; if (nr_frames == 0) return 0; -- 2.38.1 Please let me know how you want to proceed. Ideally, you'd pick up [1] and apply this updated patch. Also, please tell me if I should send this updated patch in a separate mail (e.g., as reply to this mail). [1] https://lkml.kernel.org/r/71bdd3cf-b044-3f12-df58-7c16d5749587@xs4all.nl -- Thanks, David / dhildenb