From patchwork Wed Aug 9 00:07:44 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: 9889331 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 8907A603F9 for ; Wed, 9 Aug 2017 00:09:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7C9F028908 for ; Wed, 9 Aug 2017 00:09:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7152528A0F; Wed, 9 Aug 2017 00:09:44 +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 0C99A28908 for ; Wed, 9 Aug 2017 00:09:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752267AbdHIAJk (ORCPT ); Tue, 8 Aug 2017 20:09:40 -0400 Received: from mga11.intel.com ([192.55.52.93]:36787 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752250AbdHIAJj (ORCPT ); Tue, 8 Aug 2017 20:09:39 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2017 17:09:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,345,1498546800"; d="scan'208";a="1180525951" Received: from omniknight.lm.intel.com ([10.232.112.27]) by fmsmga001.fm.intel.com with ESMTP; 08 Aug 2017 17:09:38 -0700 From: Vishal Verma To: Cc: , Dan Williams , Jeff Moyer , "Rafael J. Wysocki" , Toshi Kani , Vishal Verma , Robert Moore Subject: [PATCH v5 5/7] libnvdimm: fix potential deadlock while clearing errors Date: Tue, 8 Aug 2017 18:07:44 -0600 Message-Id: <20170809000746.10585-6-vishal.l.verma@intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170809000746.10585-1-vishal.l.verma@intel.com> References: <20170809000746.10585-1-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)