From patchwork Tue Aug 22 22:19:14 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: 9916255 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 362ED60381 for ; Tue, 22 Aug 2017 22:21:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27EA228889 for ; Tue, 22 Aug 2017 22:21:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1CE53288D8; Tue, 22 Aug 2017 22:21:17 +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=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=unavailable version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DE06E28889 for ; Tue, 22 Aug 2017 22:21:16 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 025C621E2DA77; Tue, 22 Aug 2017 15:18:42 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 24C0621E2DA5F for ; Tue, 22 Aug 2017 15:18:39 -0700 (PDT) Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP; 22 Aug 2017 15:21:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,414,1498546800"; d="scan'208";a="140891276" Received: from omniknight.lm.intel.com ([10.232.112.27]) by orsmga005.jf.intel.com with ESMTP; 22 Aug 2017 15:21:11 -0700 From: Vishal Verma To: Subject: [PATCH v6 5/6] libnvdimm: fix potential deadlock while clearing errors Date: Tue, 22 Aug 2017 16:19:14 -0600 Message-Id: <20170822221915.1732-6-vishal.l.verma@intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170822221915.1732-1-vishal.l.verma@intel.com> References: <20170822221915.1732-1-vishal.l.verma@intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Rafael J . Wysocki" , Robert Moore , linux-acpi@vger.kernel.org MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" 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)