From patchwork Wed Dec 4 21:36:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11273637 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 C09B36C1 for ; Wed, 4 Dec 2019 21:36:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8C85E206DF for ; Wed, 4 Dec 2019 21:36:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="eCFl7oV6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C85E206DF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4F1756B0CAB; Wed, 4 Dec 2019 16:36:08 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 4A1096B0CAC; Wed, 4 Dec 2019 16:36:08 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3900D6B0CAD; Wed, 4 Dec 2019 16:36:08 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id 09C3A6B0CAC for ; Wed, 4 Dec 2019 16:36:08 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 94301180AD80F for ; Wed, 4 Dec 2019 21:36:07 +0000 (UTC) X-FDA: 76228767174.14.route63_356751d111c29 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,jhubbard@nvidia.com,:akpm@linux-foundation.org:jgg@ziepe.ca:leon@kernel.org:hch@infradead.org:ira.weiny@intel.com:linux-rdma@vger.kernel.org::linux-kernel@vger.kernel.org:jhubbard@nvidia.com:hch@lst.de,RULES_HIT:30054:30064:30069,0,RBL:216.228.121.64:@nvidia.com:.lbl8.mailshell.net-62.18.0.100 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: route63_356751d111c29 X-Filterd-Recvd-Size: 4087 Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Dec 2019 21:36:06 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 04 Dec 2019 13:36:01 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 04 Dec 2019 13:36:05 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 04 Dec 2019 13:36:05 -0800 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 4 Dec 2019 21:36:04 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Wed, 4 Dec 2019 21:36:04 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Wed, 04 Dec 2019 13:36:04 -0800 From: John Hubbard To: Andrew Morton , Jason Gunthorpe , Leon Romanovsky , Christoph Hellwig CC: Ira Weiny , , , LKML , John Hubbard , Christoph Hellwig Subject: [PATCH v2 1/2] mm/gup: allow FOLL_FORCE for get_user_pages_fast() Date: Wed, 4 Dec 2019 13:36:02 -0800 Message-ID: <20191204213603.464373-2-jhubbard@nvidia.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191204213603.464373-1-jhubbard@nvidia.com> References: <20191204213603.464373-1-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=1575495361; bh=D5FKf6o88yrnam68mO83xEuXphYTA3McnnbS0GFu5aA=; 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=eCFl7oV6N1zFHWhmaXu9MCkZmrub7KXbOYWLH/D/jUkygF0DtjswPT2qe+aARAZFH jalNYGfDUmDPJZcLuaNkfZQs5g8cxMa8gn/wgOSGkjteGuJH6rxi6NZuRw1Vlaqb2E 7uzMo7yCYyx1ZuotG2ThIsFANYlKuS2hdorpsuhz/r8JOAo/QWLOsWH+ytGPxUtk/8 Ge1jG58RtT9eRllOlBhF4qIJXXoZlK8xvAZ47WoMzWeGx9KoUM3NYZ65MgiySrtka4 w41lEaiz0oliyAhaKRxPeLlCM2bWfLxMhWhwnoW+cxAjJU3TqbQlXWqq9wKural0c/ P45ahLYmbnzlA== 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: 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 Signed-off-by: John Hubbard Reviewed-by: Leon Romanovsky --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index 7646bf993b25..5244b8090440 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2415,7 +2415,8 @@ 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;