From patchwork Wed Jul 26 23:35:45 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: 9866013 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 A34F0603F9 for ; Wed, 26 Jul 2017 23:37:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9542B287CF for ; Wed, 26 Jul 2017 23:37:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A54B287E0; Wed, 26 Jul 2017 23:37:48 +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 1F418287CF for ; Wed, 26 Jul 2017 23:37:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751459AbdGZXhq (ORCPT ); Wed, 26 Jul 2017 19:37:46 -0400 Received: from mga07.intel.com ([134.134.136.100]:21047 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751445AbdGZXho (ORCPT ); Wed, 26 Jul 2017 19:37:44 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP; 26 Jul 2017 16:37:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,417,1496127600"; d="scan'208";a="883202700" Received: from omniknight.lm.intel.com ([10.232.112.27]) by FMSMGA003.fm.intel.com with ESMTP; 26 Jul 2017 16:37:43 -0700 From: Vishal Verma To: Cc: , Dan Williams , Jeff Moyer , "Rafael J. Wysocki" , Toshi Kani , Vishal Verma , Robert Moore Subject: [PATCH v4 5/6] libnvdimm: fix potential deadlock while clearing errors Date: Wed, 26 Jul 2017 17:35:45 -0600 Message-Id: <20170726233546.29052-6-vishal.l.verma@intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170726233546.29052-1-vishal.l.verma@intel.com> References: <20170726233546.29052-1-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)