From patchwork Wed Jan 29 03:24:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11355457 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 6FE31924 for ; Wed, 29 Jan 2020 03:25:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F31F20CC7 for ; Wed, 29 Jan 2020 03:25:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="EhqNcx+B" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726834AbgA2DYY (ORCPT ); Tue, 28 Jan 2020 22:24:24 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:6363 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726821AbgA2DYX (ORCPT ); Tue, 28 Jan 2020 22:24:23 -0500 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 28 Jan 2020 19:23:29 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Tue, 28 Jan 2020 19:24:19 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Tue, 28 Jan 2020 19:24:19 -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, 29 Jan 2020 03:24:19 +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, 29 Jan 2020 03:24:19 +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, 28 Jan 2020 19:24:19 -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 , , , , , , LKML , John Hubbard Subject: [PATCH v2 2/8] mm/gup: split get_user_pages_remote() into two routines Date: Tue, 28 Jan 2020 19:24:11 -0800 Message-ID: <20200129032417.3085670-3-jhubbard@nvidia.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200129032417.3085670-1-jhubbard@nvidia.com> References: <20200129032417.3085670-1-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=1580268209; bh=OqBHG8Cvzy5SUmSIVRhUFA6MUB8FlDhy13/SE4T+y3g=; 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=EhqNcx+BId5ScdK+8BMY3I/PtU+jyKecY6pV0vMefq0prO4cXpetrJaJ5PHh6xGaZ eU3OGY49mCA8O/v7N9MGRqIvYndPComezY4hbrqVVKhTtQupjlXKlfezeWjbQOEYzx CFHAKZmXD5oJ/WIjZR/q0fjLYncCWMa5vBxQc0aofppP4JFA8a7DpZ3kpnVofKMYeh vRQW882CJadvtV0E4NNYqfhk6Y32VNjdvMcckCOh+U+DAIyilI+N1b3UAoPKpTRCZ8 oiQ/GBLvR2SHBS3WPh6TtL2ZCPeL6m2DAHdS2XuZE6o85azFfCgPFgtZnecQFtUSO8 TYLXdYjcsIrag== Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org An upcoming patch requires reusing the implementation of get_user_pages_remote(). Split up get_user_pages_remote() into an outer routine that checks flags, and an implementation routine that will be reused. This makes subsequent changes much easier to understand. There should be no change in behavior due to this patch. Signed-off-by: John Hubbard --- mm/gup.c | 56 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 33 insertions(+), 23 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 1b521e0ac1de..b699500da077 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1557,6 +1557,37 @@ static __always_inline long __gup_longterm_locked(struct task_struct *tsk, } #endif /* CONFIG_FS_DAX || CONFIG_CMA */ +#ifdef CONFIG_MMU +static long __get_user_pages_remote(struct task_struct *tsk, + struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + unsigned int gup_flags, struct page **pages, + struct vm_area_struct **vmas, int *locked) +{ + /* + * Parts of FOLL_LONGTERM behavior are incompatible with + * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on + * vmas. However, this only comes up if locked is set, and there are + * callers that do request FOLL_LONGTERM, but do not set locked. So, + * allow what we can. + */ + if (gup_flags & FOLL_LONGTERM) { + if (WARN_ON_ONCE(locked)) + return -EINVAL; + /* + * This will check the vmas (even if our vmas arg is NULL) + * and return -ENOTSUPP if DAX isn't allowed in this case: + */ + return __gup_longterm_locked(tsk, mm, start, nr_pages, pages, + vmas, gup_flags | FOLL_TOUCH | + FOLL_REMOTE); + } + + return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, + locked, + gup_flags | FOLL_TOUCH | FOLL_REMOTE); +} + /* * get_user_pages_remote() - pin user pages in memory * @tsk: the task_struct to use for page fault accounting, or @@ -1619,7 +1650,6 @@ static __always_inline long __gup_longterm_locked(struct task_struct *tsk, * should use get_user_pages because it cannot pass * FAULT_FLAG_ALLOW_RETRY to handle_mm_fault. */ -#ifdef CONFIG_MMU long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, @@ -1632,28 +1662,8 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, if (WARN_ON_ONCE(gup_flags & FOLL_PIN)) return -EINVAL; - /* - * Parts of FOLL_LONGTERM behavior are incompatible with - * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on - * vmas. However, this only comes up if locked is set, and there are - * callers that do request FOLL_LONGTERM, but do not set locked. So, - * allow what we can. - */ - if (gup_flags & FOLL_LONGTERM) { - if (WARN_ON_ONCE(locked)) - return -EINVAL; - /* - * This will check the vmas (even if our vmas arg is NULL) - * and return -ENOTSUPP if DAX isn't allowed in this case: - */ - return __gup_longterm_locked(tsk, mm, start, nr_pages, pages, - vmas, gup_flags | FOLL_TOUCH | - FOLL_REMOTE); - } - - return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, - locked, - gup_flags | FOLL_TOUCH | FOLL_REMOTE); + return __get_user_pages_remote(tsk, mm, start, nr_pages, gup_flags, + pages, vmas, locked); } EXPORT_SYMBOL(get_user_pages_remote);