From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD3E6C2D0FB for ; Wed, 13 May 2020 01:50:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9943E20714 for ; Wed, 13 May 2020 01:50:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728797AbgEMBuL (ORCPT ); Tue, 12 May 2020 21:50:11 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:4398 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726028AbgEMBuK (ORCPT ); Tue, 12 May 2020 21:50:10 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 73FC533283DC5F6787D9; Wed, 13 May 2020 09:50:08 +0800 (CST) Received: from [10.65.58.147] (10.65.58.147) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Wed, 13 May 2020 09:50:00 +0800 Subject: Re: [PATCH v1 1/1] PCI/ERR: Handle fatal error recovery for non-hotplug capable devices To: Jay Vosburgh , References: <18609.1588812972@famine> <9908.1589311230@famine> CC: , , , , liudongdong 00290354 , Linuxarm From: Yicong Yang Message-ID: <1216d38b-bc0a-b4d5-967f-f5a86d96287c@hisilicon.com> Date: Wed, 13 May 2020 09:50:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <9908.1589311230@famine> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.65.58.147] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/5/13 3:20, Jay Vosburgh wrote: > sathyanarayanan.kuppuswamy@linux.intel.com wrote: > >> From: Kuppuswamy Sathyanarayanan >> >> If there are non-hotplug capable devices connected to a given >> port, then during the fatal error recovery(triggered by DPC or >> AER), after calling reset_link() function, we cannot rely on >> hotplug handler to detach and re-enumerate the device drivers >> in the affected bus. Instead, we will have to let the error >> recovery handler call report_slot_reset() for all devices in >> the bus to notify about the reset operation. Although this is >> only required for non hot-plug capable devices, doing it for >> hotplug capable devices should not affect the functionality. > Yicong, > > Does the patch below also resolve the issue for you, as with > your changed version of my original patch? Yes. It works. > > -J > >> Along with above issue, this fix also applicable to following >> issue. >> >> Commit 6d2c89441571 ("PCI/ERR: Update error status after >> reset_link()") added support to store status of reset_link() >> call. Although this fixed the error recovery issue observed if >> the initial value of error status is PCI_ERS_RESULT_DISCONNECT >> or PCI_ERS_RESULT_NO_AER_DRIVER, it also discarded the status >> result from report_frozen_detected. This can cause a failure to >> recover if _NEED_RESET is returned by report_frozen_detected and >> report_slot_reset is not invoked. >> >> Such an event can be induced for testing purposes by reducing the >> Max_Payload_Size of a PCIe bridge to less than that of a device >> downstream from the bridge, and then initiating I/O through the >> device, resulting in oversize transactions. In the presence of DPC, >> this results in a containment event and attempted reset and recovery >> via pcie_do_recovery. After 6d2c89441571 report_slot_reset is not >> invoked, and the device does not recover. >> >> [original patch is from jay.vosburgh@canonical.com] >> [original patch link https://lore.kernel.org/linux-pci/18609.1588812972@famine/] >> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") >> Signed-off-by: Jay Vosburgh >> Signed-off-by: Kuppuswamy Sathyanarayanan >> --- >> drivers/pci/pcie/err.c | 19 +++++++++++++++---- >> 1 file changed, 15 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c >> index 14bb8f54723e..db80e1ecb2dc 100644 >> --- a/drivers/pci/pcie/err.c >> +++ b/drivers/pci/pcie/err.c >> @@ -165,13 +165,24 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, >> pci_dbg(dev, "broadcast error_detected message\n"); >> if (state == pci_channel_io_frozen) { >> pci_walk_bus(bus, report_frozen_detected, &status); >> - status = reset_link(dev); >> - if (status != PCI_ERS_RESULT_RECOVERED) { >> + status = PCI_ERS_RESULT_NEED_RESET; >> + } else { >> + pci_walk_bus(bus, report_normal_detected, &status); >> + } >> + >> + if (status == PCI_ERS_RESULT_NEED_RESET) { >> + if (reset_link) { >> + if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) >> + status = PCI_ERS_RESULT_DISCONNECT; >> + } else { >> + if (pci_bus_error_reset(dev)) >> + status = PCI_ERS_RESULT_DISCONNECT; >> + } >> + >> + if (status == PCI_ERS_RESULT_DISCONNECT) { >> pci_warn(dev, "link reset failed\n"); >> goto failed; >> } >> - } else { >> - pci_walk_bus(bus, report_normal_detected, &status); >> } >> >> if (status == PCI_ERS_RESULT_CAN_RECOVER) { >> -- >> 2.17.1 >> > --- > -Jay Vosburgh, jay.vosburgh@canonical.com > . >