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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 6B0A6C433E2 for ; Fri, 17 Jul 2020 07:49:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2F54920768 for ; Fri, 17 Jul 2020 07:49:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F54920768 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B0F9A8D0003; Fri, 17 Jul 2020 03:49:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AC1F28D0001; Fri, 17 Jul 2020 03:49:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9B02C8D0003; Fri, 17 Jul 2020 03:49:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0135.hostedemail.com [216.40.44.135]) by kanga.kvack.org (Postfix) with ESMTP id 853B88D0001 for ; Fri, 17 Jul 2020 03:49:20 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 18A838248047 for ; Fri, 17 Jul 2020 07:49:20 +0000 (UTC) X-FDA: 77046792480.04.van23_5015a2026f09 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 496B980217EE for ; Fri, 17 Jul 2020 07:47:47 +0000 (UTC) X-HE-Tag: van23_5015a2026f09 X-Filterd-Recvd-Size: 3265 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Fri, 17 Jul 2020 07:45:44 +0000 (UTC) IronPort-SDR: IO7KM0BkDpnGo67CYphJwCvl16qYPigqvjbGPzuzlKG4vop8EXS6lNqqL/cSI8E6eveWF3KfMw UoeLLqHl7T5g== X-IronPort-AV: E=McAfee;i="6000,8403,9684"; a="167682242" X-IronPort-AV: E=Sophos;i="5.75,362,1589266800"; d="scan'208";a="167682242" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2020 00:21:09 -0700 IronPort-SDR: YpmkIwj70j6oVnuZCPgm7Puk0Ze/LdT6Mtx+PLsWg4I1ZRpbL4Ii+GQfOj73MXeOUOarxnJ+rq LsrpPStzFBzg== X-IronPort-AV: E=Sophos;i="5.75,362,1589266800"; d="scan'208";a="282708053" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2020 00:21:08 -0700 From: ira.weiny@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Cc: Ira Weiny , x86@kernel.org, Dave Hansen , Dan Williams , Vishal Verma , Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: [PATCH RFC V2 14/17] dax: Stray write protection for dax_direct_access() Date: Fri, 17 Jul 2020 00:20:53 -0700 Message-Id: <20200717072056.73134-15-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20200717072056.73134-1-ira.weiny@intel.com> References: <20200717072056.73134-1-ira.weiny@intel.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 496B980217EE X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 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: From: Ira Weiny dax_direct_access() is a special case of accessing pmem via a page offset and without a struct page. Because the dax driver is well aware of the special protections it has mapped memory with, call dev_access_[en|dis]able() directly instead of the unnecessary overhead of trying to get a page to kmap. Like kmap though, leverage the existing dax_read[un]lock() functions because they are already required to surround the use of the memory returned from dax_direct_access(). Signed-off-by: Ira Weiny --- drivers/dax/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 021739768093..e8d0a28e6ed2 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -30,12 +30,14 @@ static DEFINE_SPINLOCK(dax_host_lock); =20 int dax_read_lock(void) { + dev_access_enable(); return srcu_read_lock(&dax_srcu); } EXPORT_SYMBOL_GPL(dax_read_lock); =20 void dax_read_unlock(int id) { + dev_access_disable(); srcu_read_unlock(&dax_srcu, id); } EXPORT_SYMBOL_GPL(dax_read_unlock); --=20 2.28.0.rc0.12.gb6a658bd00c9