From patchwork Sat Feb 1 03:40:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11360899 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 A25D5139A for ; Sat, 1 Feb 2020 03:41:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 813172173E for ; Sat, 1 Feb 2020 03:41:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="ZWO0bU5d" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727176AbgBADkj (ORCPT ); Fri, 31 Jan 2020 22:40:39 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:4472 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727152AbgBADkj (ORCPT ); Fri, 31 Jan 2020 22:40:39 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 31 Jan 2020 19:39:43 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 31 Jan 2020 19:40:36 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 31 Jan 2020 19:40:36 -0800 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 1 Feb 2020 03:40:36 +0000 Received: from rnnvemgw01.nvidia.com (10.128.109.123) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Sat, 1 Feb 2020 03:40:36 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by rnnvemgw01.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Fri, 31 Jan 2020 19:40:35 -0800 From: John Hubbard To: Andrew Morton CC: Al Viro , Christoph Hellwig , Dan Williams , Dave Chinner , Ira Weiny , Jan Kara , Jason Gunthorpe , Jonathan Corbet , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , "Kirill A . Shutemov" , Michal Hocko , Mike Kravetz , Shuah Khan , Vlastimil Babka , Matthew Wilcox , , , , , , LKML , John Hubbard Subject: [PATCH v3 06/12] mm/gup: require FOLL_GET for get_user_pages_fast() Date: Fri, 31 Jan 2020 19:40:23 -0800 Message-ID: <20200201034029.4063170-7-jhubbard@nvidia.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200201034029.4063170-1-jhubbard@nvidia.com> References: <20200201034029.4063170-1-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=1580528383; bh=Z9uI90D5Af1XE4HB0iXcZz0iIFq8KeG+V2UZnNU7A3I=; 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=ZWO0bU5dS7wz1ASmGWmadruPr2XEHoOFdREk1Ke1iHPAZZYuUNzk8uz50X9vueHEB uwZ73YDTr6KYSQ5E35pOxHJiQdkGf/7OBL7iAThpFgXJ5kFHPa2HQfK4FXXFAYbQIY ALJmyCjklVhburx0FZrCWyjGGCwHjjdOiNsKV9uGTTYydQVra9MWa06V2rAMKrEZBD /hte6FfbtMYdBoQesavwuEUktsLBXWBDV1datYFOopPbrrylpSx2VMlMeiYzqr0Pmc 0vyAxJ/hJYGjVsdN5jmGh/tEVce6NMxA2cwxv6ZAPWdatb5VoYIOQmysiRemQGmLYa o5oselPb3l4tQ== Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Internal to mm/gup.c, require that get_user_pages_fast() and __get_user_pages_fast() identify themselves, by setting FOLL_GET. This is required in order to be able to make decisions based on "FOLL_PIN, or FOLL_GET, or both or neither are set", in upcoming patches. Signed-off-by: John Hubbard Acked-by: Kirill A. Shutemov Reviewed-by: Jan Kara --- mm/gup.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 83473c2165f4..e899d2e6398c 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2390,6 +2390,14 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, unsigned long len, end; unsigned long flags; int nr = 0; + /* + * Internally (within mm/gup.c), gup fast variants must set FOLL_GET, + * because gup fast is always a "pin with a +1 page refcount" request. + */ + unsigned int gup_flags = FOLL_GET; + + if (write) + gup_flags |= FOLL_WRITE; start = untagged_addr(start) & PAGE_MASK; len = (unsigned long) nr_pages << PAGE_SHIFT; @@ -2415,7 +2423,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) && gup_fast_permitted(start, end)) { local_irq_save(flags); - gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr); + gup_pgd_range(start, end, gup_flags, pages, &nr); local_irq_restore(flags); } @@ -2454,7 +2462,7 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages, int nr = 0, ret = 0; if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | - FOLL_FORCE | FOLL_PIN))) + FOLL_FORCE | FOLL_PIN | FOLL_GET))) return -EINVAL; start = untagged_addr(start) & PAGE_MASK; @@ -2521,6 +2529,13 @@ int get_user_pages_fast(unsigned long start, int nr_pages, if (WARN_ON_ONCE(gup_flags & FOLL_PIN)) return -EINVAL; + /* + * The caller may or may not have explicitly set FOLL_GET; either way is + * OK. However, internally (within mm/gup.c), gup fast variants must set + * FOLL_GET, because gup fast is always a "pin with a +1 page refcount" + * request. + */ + gup_flags |= FOLL_GET; return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages); } EXPORT_SYMBOL_GPL(get_user_pages_fast);