From patchwork Thu Aug 31 01:36:02 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Verma, Vishal L" X-Patchwork-Id: 9931033 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7E975602F0 for ; Thu, 31 Aug 2017 01:38:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 71BD8287FE for ; Thu, 31 Aug 2017 01:38:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 665612880A; Thu, 31 Aug 2017 01:38:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7331A28813 for ; Thu, 31 Aug 2017 01:38:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750814AbdHaBiK (ORCPT ); Wed, 30 Aug 2017 21:38:10 -0400 Received: from mga06.intel.com ([134.134.136.31]:54299 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774AbdHaBiK (ORCPT ); Wed, 30 Aug 2017 21:38:10 -0400 Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga104.jf.intel.com with ESMTP; 30 Aug 2017 18:38:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,451,1498546800"; d="scan'208";a="146520839" Received: from omniknight.lm.intel.com ([10.232.112.27]) by fmsmga006.fm.intel.com with ESMTP; 30 Aug 2017 18:38:09 -0700 From: Vishal Verma To: Cc: Dan Williams , Jeff Moyer , Toshi Kani , Vishal Verma , linux-acpi@vger.kernel.org, Robert Moore , "Rafael J . Wysocki" Subject: [PATCH v7 5/6] libnvdimm: fix potential deadlock while clearing errors Date: Wed, 30 Aug 2017 19:36:02 -0600 Message-Id: <20170831013603.16997-6-vishal.l.verma@intel.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20170831013603.16997-1-vishal.l.verma@intel.com> References: <20170831013603.16997-1-vishal.l.verma@intel.com> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With the ACPI NFIT 'DSM' methods, acpi can be called from IO paths. Specifically, the DSM to clear media errors is called during writes, so that we can provide a writes-fix-errors model. However it is easy to imagine a scenario like: -> write through the nvdimm driver -> acpi allocation -> writeback, causes more IO through the nvdimm driver -> deadlock Fix this by using memalloc_noio_{save,restore}, which sets the GFP_NOIO flag for the current scope when issuing commands/IOs that are expected to clear errors. Cc: Cc: Cc: Dan Williams Cc: Robert Moore Cc: Rafael J. Wysocki Signed-off-by: Vishal Verma --- drivers/nvdimm/bus.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index 937fafa..a18c291 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -11,6 +11,7 @@ * General Public License for more details. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -234,6 +235,7 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys, struct nd_cmd_clear_error clear_err; struct nd_cmd_ars_cap ars_cap; u32 clear_err_unit, mask; + unsigned int noio_flag; int cmd_rc, rc; if (!nvdimm_bus) @@ -250,8 +252,10 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys, memset(&ars_cap, 0, sizeof(ars_cap)); ars_cap.address = phys; ars_cap.length = len; + noio_flag = memalloc_noio_save(); rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, &ars_cap, sizeof(ars_cap), &cmd_rc); + memalloc_noio_restore(noio_flag); if (rc < 0) return rc; if (cmd_rc < 0) @@ -266,8 +270,10 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys, memset(&clear_err, 0, sizeof(clear_err)); clear_err.address = phys; clear_err.length = len; + noio_flag = memalloc_noio_save(); rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_CLEAR_ERROR, &clear_err, sizeof(clear_err), &cmd_rc); + memalloc_noio_restore(noio_flag); if (rc < 0) return rc; if (cmd_rc < 0)