From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A3A5C3F2D8 for ; Tue, 3 Mar 2020 18:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3ED94208C3 for ; Tue, 3 Mar 2020 18:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258974; bh=wwYAtY6bjKNZ28ZOO+yoynbjZWU+rFBQW1m8byw9ZuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uRiN1punBdeszCaNafxVPO9OS0RSsHXUsXkXsq7fD/nXHeIbwS6uPMHRLj5Gu2N77 gp6kxb8N8bfWmLkkp485AL1jYFITTBmWBQIFf4ZnJCUzagT/N9SQ6Il7Q8NAzQ3Mko 9x2hju3PK46AFgf7H+r/6dI3bKkIb5ypPle/mDAs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730890AbgCCRwP (ORCPT ); Tue, 3 Mar 2020 12:52:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:60438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbgCCRwK (ORCPT ); Tue, 3 Mar 2020 12:52:10 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC9DB206D5; Tue, 3 Mar 2020 17:52:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257930; bh=wwYAtY6bjKNZ28ZOO+yoynbjZWU+rFBQW1m8byw9ZuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1YHuZyhsrVbzcxVVkMjWVSWJTp0lklt5woKqTmYWKHZ5i4JhebZmOsTC3kZUwyaM5 R0NWX5b8K/9GCpIqjy2qhVUDSblX3q6u7WCSOAQBT2/891dyafw5oaIDLMGvoDfVnF pqY9e8i4zayc0wXcj3jklqBiMDNT9Z7XBTsZgwvE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Hubbard , Leon Romanovsky , Jan Kara , Christoph Hellwig , Alex Williamson , "Aneesh Kumar K.V" , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Daniel Vetter , Dan Williams , Hans Verkuil , Ira Weiny , Jason Gunthorpe , Jason Gunthorpe , Jens Axboe , Jerome Glisse , Jonathan Corbet , "Kirill A. Shutemov" , Mauro Carvalho Chehab , Mike Rapoport , Andrew Morton , Linus Torvalds Subject: [PATCH 5.5 172/176] mm/gup: allow FOLL_FORCE for get_user_pages_fast() Date: Tue, 3 Mar 2020 18:43:56 +0100 Message-Id: <20200303174323.801359431@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174304.593872177@linuxfoundation.org> References: <20200303174304.593872177@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: John Hubbard commit f4000fdf435b8301a11cf85237c561047f8c4c72 upstream. 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(). Link: http://lkml.kernel.org/r/20200107224558.2362728-9-jhubbard@nvidia.com Fixes: 817be129e6f2 ("mm: validate get_user_pages_fast flags") Signed-off-by: John Hubbard Reviewed-by: Leon Romanovsky Reviewed-by: Jan Kara Cc: Christoph Hellwig Cc: Alex Williamson Cc: Aneesh Kumar K.V Cc: Björn Töpel Cc: Daniel Vetter Cc: Dan Williams Cc: Hans Verkuil Cc: Ira Weiny Cc: Jason Gunthorpe Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Jerome Glisse Cc: Jonathan Corbet Cc: Kirill A. Shutemov Cc: Mauro Carvalho Chehab Cc: Mike Rapoport Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/gup.c +++ b/mm/gup.c @@ -2415,7 +2415,8 @@ int get_user_pages_fast(unsigned long st 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;