From patchwork Thu Jul 4 07:50:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiongfeng Wang X-Patchwork-Id: 1127388 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45fVZj6Rlyz9sBp for ; Thu, 4 Jul 2019 17:53:01 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727279AbfGDHxA (ORCPT ); Thu, 4 Jul 2019 03:53:00 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:8140 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727180AbfGDHxA (ORCPT ); Thu, 4 Jul 2019 03:53:00 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id EF7DE4A3A00B8D6F92BC; Thu, 4 Jul 2019 15:52:57 +0800 (CST) Received: from linux-ibm.site (10.175.102.37) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Thu, 4 Jul 2019 15:52:49 +0800 From: Xiongfeng Wang To: , CC: , , , , , Subject: [RFC PATCH] pciehp: use completion to wait irq_thread 'pciehp_ist' Date: Thu, 4 Jul 2019 15:50:38 +0800 Message-ID: <1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com> X-Mailer: git-send-email 1.7.12.4 MIME-Version: 1.0 X-Originating-IP: [10.175.102.37] X-CFilter-Loop: Reflected Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When I use the following command to power on a slot which has been powered off already. echo 1 > /sys/bus/pci/slots/22/power It prints the following error: -bash: echo: write error: No such device But the slot is actually powered on and the devices is probed. In function 'pciehp_sysfs_enable_slot()', we use 'wait_event()' to wait until 'ctrl->pending_events' is cleared in 'pciehp_ist()'. But in some situation, when 'pciehp_ist()' is woken up on a nearby CPU after 'pciehp_request' is called, 'ctrl->pending_events' is cleared before we go into sleep state. 'wait_event()' will check the condition before going into sleep. So we return immediately and '-ENODEV' is return. This patch use struct completion to wait until irq_thread 'pciehp_ist' is completed. Signed-off-by: Xiongfeng Wang Reported-by: Xiongfeng Wang Signed-off-by: Lukas Wunner --- drivers/pci/hotplug/pciehp.h | 2 +- drivers/pci/hotplug/pciehp_ctrl.c | 8 ++++---- drivers/pci/hotplug/pciehp_hpc.c | 4 ++-- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 8c51a04..f8c3826 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -102,7 +102,7 @@ struct controller { struct hotplug_slot hotplug_slot; /* hotplug core interface */ struct rw_semaphore reset_lock; int request_result; - wait_queue_head_t requester; + struct completion requester; }; /** diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index 631ced0..2237793 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -366,9 +366,9 @@ int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot) * card before the thread wakes up, so initialize to -ENODEV. */ ctrl->request_result = -ENODEV; + reinit_completion(&ctrl->requester); pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC); - wait_event(ctrl->requester, - !atomic_read(&ctrl->pending_events)); + wait_for_completion(&ctrl->requester); return ctrl->request_result; case POWERON_STATE: ctrl_info(ctrl, "Slot(%s): Already in powering on state\n", @@ -399,9 +399,9 @@ int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot) case BLINKINGOFF_STATE: case ON_STATE: mutex_unlock(&ctrl->state_lock); + reinit_completion(&ctrl->requester); pciehp_request(ctrl, DISABLE_SLOT); - wait_event(ctrl->requester, - !atomic_read(&ctrl->pending_events)); + wait_for_completion(&ctrl->requester); return ctrl->request_result; case POWEROFF_STATE: ctrl_info(ctrl, "Slot(%s): Already in powering off state\n", diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index bd990e3..0a74b48 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -654,7 +654,7 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) up_read(&ctrl->reset_lock); pci_config_pm_runtime_put(pdev); - wake_up(&ctrl->requester); + complete(&ctrl->requester); return IRQ_HANDLED; } @@ -862,7 +862,7 @@ struct controller *pcie_init(struct pcie_device *dev) mutex_init(&ctrl->ctrl_lock); mutex_init(&ctrl->state_lock); init_rwsem(&ctrl->reset_lock); - init_waitqueue_head(&ctrl->requester); + init_completion(&ctrl->requester); init_waitqueue_head(&ctrl->queue); INIT_DELAYED_WORK(&ctrl->button_work, pciehp_queue_pushbutton_work); dbg_ctrl(ctrl);