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=-21.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 C26BEC43214 for ; Fri, 27 Aug 2021 14:40:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 421DB60E93 for ; Fri, 27 Aug 2021 14:40:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 421DB60E93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cn.fujitsu.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B4C518D0002; Fri, 27 Aug 2021 10:40:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AFD328D0001; Fri, 27 Aug 2021 10:40:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9EA778D0002; Fri, 27 Aug 2021 10:40:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id 8385C8D0001 for ; Fri, 27 Aug 2021 10:40:23 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 28345256E9 for ; Fri, 27 Aug 2021 14:40:23 +0000 (UTC) X-FDA: 78521121126.36.003FB3E Received: from heian.cn.fujitsu.com (mail.cn.fujitsu.com [183.91.158.132]) by imf29.hostedemail.com (Postfix) with ESMTP id 64E2A9000247 for ; Fri, 27 Aug 2021 14:40:22 +0000 (UTC) IronPort-HdrOrdr: =?us-ascii?q?A9a23=3A2npoUagCEbajKHeHnHDuQbZJ3XBQXr8ji2hC?= =?us-ascii?q?6mlwRA09TyX4raCTdZsguCMc5Ax6ZJhCo7G90cu7Lk80nKQdieIs1N+ZLWrbUQ?= =?us-ascii?q?CTQL2Kg7GN/wHd?= X-IronPort-AV: E=Sophos;i="5.84,356,1620662400"; d="scan'208";a="113573694" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 27 Aug 2021 22:40:18 +0800 Received: from G08CNEXMBPEKD04.g08.fujitsu.local (unknown [10.167.33.201]) by cn.fujitsu.com (Postfix) with ESMTP id F288C4D0DC6D; Fri, 27 Aug 2021 22:40:14 +0800 (CST) Received: from G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.85) by G08CNEXMBPEKD04.g08.fujitsu.local (10.167.33.201) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Fri, 27 Aug 2021 22:40:15 +0800 Received: from localhost.localdomain (10.167.225.141) by G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.23 via Frontend Transport; Fri, 27 Aug 2021 22:40:14 +0800 From: Li Zhijian To: , , , , CC: , , Li Zhijian , Subject: [PATCH] mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled Date: Fri, 27 Aug 2021 22:45:00 +0800 Message-ID: <20210827144500.2148-1-lizhijian@cn.fujitsu.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Type: text/plain X-yoursite-MailScanner-ID: F288C4D0DC6D.AEC5F X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: lizhijian@fujitsu.com Authentication-Results: imf29.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=fujitsu.com (policy=none); spf=none (imf29.hostedemail.com: domain of lizhijian@fujitsu.com has no SPF policy when checking 183.91.158.132) smtp.mailfrom=lizhijian@fujitsu.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 64E2A9000247 X-Stat-Signature: wn81hxfu8jc7qhug89c17so37in33yzr X-HE-Tag: 1630075222-395587 Content-Transfer-Encoding: quoted-printable 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: Previously, we noticed the one rpma example was failed[1] since 36f30e486= d, where it will use ODP feature to do RDMA WRITE between fsdax files. After digging into the code, we found hmm_vma_handle_pte() will still return EFAULT even though all the its requesting flags has been fulfilled. That's because a DAX page will be marked as (_PAGE_SPECIAL | PAGE_DEVMAP) by pte_mkdevmap(). [1]: https://github.com/pmem/rpma/issues/1142 CC: stable@vger.kernel.org Signed-off-by: Li Zhijian --- mm/hmm.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/hmm.c b/mm/hmm.c index fad6be2bf072..4766bdefb6c3 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -294,6 +294,12 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, = unsigned long addr, if (required_fault) goto fault; =20 + /* + * just bypass devmap pte such as DAX page when all pfn requested + * flags(pfn_req_flags) are fulfilled. + */ + if (pte_devmap(pte)) + goto out; /* * Since each architecture defines a struct page for the zero page, jus= t * fall through and treat it like a normal page. @@ -307,6 +313,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, u= nsigned long addr, return 0; } =20 +out: *hmm_pfn =3D pte_pfn(pte) | cpu_flags; return 0; =20 --=20 2.31.1