From patchwork Tue Jan 7 22:45:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11321991 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C90CE6C1 for ; Tue, 7 Jan 2020 22:46:27 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A7417207E0 for ; Tue, 7 Jan 2020 22:46:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="mG+9fbuP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7417207E0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 37A656E14A; Tue, 7 Jan 2020 22:46:09 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from hqnvemgate26.nvidia.com (hqnvemgate26.nvidia.com [216.228.121.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id CA47A6E14C for ; Tue, 7 Jan 2020 22:46:05 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 07 Jan 2020 14:45:48 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 07 Jan 2020 14:46:05 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 07 Jan 2020 14:46:05 -0800 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 7 Jan 2020 22:46:04 +0000 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 7 Jan 2020 22:46:00 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Tue, 7 Jan 2020 22:46:00 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7, 5, 8, 10121) id ; Tue, 07 Jan 2020 14:46:00 -0800 From: John Hubbard To: Andrew Morton Subject: [PATCH v12 08/22] mm/gup: allow FOLL_FORCE for get_user_pages_fast() Date: Tue, 7 Jan 2020 14:45:44 -0800 Message-ID: <20200107224558.2362728-9-jhubbard@nvidia.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200107224558.2362728-1-jhubbard@nvidia.com> References: <20200107224558.2362728-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1578437148; bh=TKqZFchMOwUlq4p7fLQxPoHAtQiavcs6JsnhT764GJ8=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=mG+9fbuPmRlJzn1vkUiL8z+GBw7cTMpiOq//DKxiIsJyjBuW9nskzY9Db1uGxi6bP 3ZIAqNsLjmLRXPSbZYVOBFeMoUwUnDTSa2wxsZxFLuqr5GC9/g9zXt/3Cl7pp+uB71 +IADVEr0VJBH1KiohQW5IgXZN2GTRvi5Xhu9ckuMd8e+2RukQAYcLu5Bad1ZsQoRx5 Z3jS4qtWjHSMNbGSC8r3PEh6d5BoRfQGRPbEhr7FdaPV1nqridJwm1WzOvlvps8ckB t1Bggqn6B8DKgBmn4XZpBuPSSSwSbgVZdTWliRoZQ/RSe00MsS0frDzgg6WKn0Gpod Ob3FCZwyu+hXw== 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: Michal Hocko , Jan Kara , kvm@vger.kernel.org, linux-doc@vger.kernel.org, David Airlie , Dave Chinner , dri-devel@lists.freedesktop.org, LKML , linux-mm@kvack.org, Paul Mackerras , linux-kselftest@vger.kernel.org, Ira Weiny , Christoph Hellwig , Jonathan Corbet , linux-rdma@vger.kernel.org, Michael Ellerman , Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , linux-media@vger.kernel.org, Shuah Khan , John Hubbard , linux-block@vger.kernel.org, Leon Romanovsky , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Al Viro , "Kirill A . Shutemov" , Dan Williams , Mauro Carvalho Chehab , Magnus Karlsson , Jens Axboe , netdev@vger.kernel.org, Alex Williamson , linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "David S . Miller" , Mike Kravetz Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Commit 817be129e6f2 ("mm: validate get_user_pages_fast flags") allowed only FOLL_WRITE and FOLL_LONGTERM to be passed to get_user_pages_fast(). This, combined with the fact that get_user_pages_fast() falls back to "slow gup", which *does* accept FOLL_FORCE, leads to an odd situation: if you need FOLL_FORCE, you cannot call get_user_pages_fast(). There does not appear to be any reason for filtering out FOLL_FORCE. There is nothing in the _fast() implementation that requires that we avoid writing to the pages. So it appears to have been an oversight. Fix by allowing FOLL_FORCE to be set for get_user_pages_fast(). Fixes: 817be129e6f2 ("mm: validate get_user_pages_fast flags") Cc: Christoph Hellwig Reviewed-by: Leon Romanovsky Reviewed-by: Jan Kara Signed-off-by: John Hubbard --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index b61bd5c469ae..a594bc708367 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2411,7 +2411,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, unsigned long addr, len, end; int nr = 0, ret = 0; - if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM))) + if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | + FOLL_FORCE))) return -EINVAL; start = untagged_addr(start) & PAGE_MASK;