From patchwork Sat Oct 3 07:55:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11815105 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0CEDA6CB for ; Sat, 3 Oct 2020 07:57:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F17AC206DB for ; Sat, 3 Oct 2020 07:57:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725813AbgJCH4z (ORCPT ); Sat, 3 Oct 2020 03:56:55 -0400 Received: from mga07.intel.com ([134.134.136.100]:28621 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725772AbgJCH4y (ORCPT ); Sat, 3 Oct 2020 03:56:54 -0400 IronPort-SDR: ubbV0E2aCLjO5UBwksVZK+NIlA6KMWgohZr4/7yI4mL9Nz6wyLS9TtDhF95pBBEvJrDLyE80X+ 6tgWP3Yt9X8A== X-IronPort-AV: E=McAfee;i="6000,8403,9762"; a="227305326" X-IronPort-AV: E=Sophos;i="5.77,330,1596524400"; d="scan'208";a="227305326" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2020 00:56:53 -0700 IronPort-SDR: 7AhYS9jzniPme7rRFE0L8MMCVkp2O6klngze1t7IrAvpgeaCvux9tUNiLdxrIK1PeVua5NTQ5w NLgpaInYcCcw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,330,1596524400"; d="scan'208";a="513063006" Received: from shskylake.sh.intel.com ([10.239.48.137]) by orsmga005.jf.intel.com with ESMTP; 03 Oct 2020 00:56:50 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, xerces.zhao@gmail.com, Ethan Zhao Subject: [PATCH v7 4/5] PCI: only return true when dev io state is really changed Date: Sat, 3 Oct 2020 03:55:13 -0400 Message-Id: <20201003075514.32935-5-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20201003075514.32935-1-haifeng.zhao@intel.com> References: <20201003075514.32935-1-haifeng.zhao@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When uncorrectable error happens, AER driver and DPC driver interrupt handlers likely call pcie_do_recovery() ->pci_walk_bus() ->report_frozen_detected() with pci_channel_io_frozen the same time. If pci_dev_set_io_state() return true even if the original state is pci_channel_io_frozen, that will cause AER or DPC handler re-enter the error detecting and recovery procedure one after another. The result is the recovery flow mixed between AER and DPC. So simplify the pci_dev_set_io_state() function to only return true when dev->error_state is really changed. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Alexandru Gagniuc Reviewed-by: Andy Shevchenko --- Changnes: v2: revise description and code according to suggestion from Andy. v3: change code to simpler. v4: no change. v5: no change. v6: no change. v7: changed based on Bjorn's code and truth table. drivers/pci/pci.h | 53 ++++++++++++++++++----------------------------- 1 file changed, 20 insertions(+), 33 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 455b32187abd..47af1ff2a286 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -354,44 +354,31 @@ struct pci_sriov { * * Must be called with device_lock held. * - * Returns true if state has been changed to the requested state. + * Returns true if state has been really changed to the requested state. */ static inline bool pci_dev_set_io_state(struct pci_dev *dev, pci_channel_state_t new) { - bool changed = false; - device_lock_assert(&dev->dev); - switch (new) { - case pci_channel_io_perm_failure: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - case pci_channel_io_perm_failure: - changed = true; - break; - } - break; - case pci_channel_io_frozen: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - changed = true; - break; - } - break; - case pci_channel_io_normal: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - changed = true; - break; - } - break; - } - if (changed) - dev->error_state = new; - return changed; + +/* + * Truth table: + * requested new state + * current ------------------------------------------ + * state normal frozen perm_failure + * ------------ + ------------- ------------- ------------ + * normal | normal frozen perm_failure + * frozen | normal frozen perm_failure + * perm_failure | perm_failure* perm_failure* perm_failure + */ + + if (dev->error_state == pci_channel_io_perm_failure) + return false; + else if (dev->error_state == new) + return false; + + dev->error_state = new; + return true; } static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)