From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:52165 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752442Ab2DPQcn (ORCPT ); Mon, 16 Apr 2012 12:32:43 -0400 Received: by mail-pb0-f46.google.com with SMTP id un15so6539626pbc.19 for ; Mon, 16 Apr 2012 09:32:43 -0700 (PDT) From: Jiang Liu To: Yinghai Lu , Kenji Kaneshige , Bjorn Helgaas , Dan Zink , Greg Kroah-Hartman , Dely Sy Cc: Jiang Liu , Jiang Liu , Keping Chen , linux-pci@vger.kernel.org Subject: [PATCH RFC 05/17] PCI: correctly flush workqueue when destroy pcie hotplug controller Date: Tue, 17 Apr 2012 00:28:59 +0800 Message-Id: <1334593751-5916-6-git-send-email-jiang.liu@huawei.com> In-Reply-To: <1334593751-5916-1-git-send-email-jiang.liu@huawei.com> References: <1334593751-5916-1-git-send-email-jiang.liu@huawei.com> Sender: linux-pci-owner@vger.kernel.org List-ID: When destroying a PCIe hotplug controller, all work items associated with that controller should be flushed. Function pcie_cleanup_slot() calls cancel_delayed_work() and flush_workqueue() to achieve that. Function flush_workqueue() will flush all work items already submitted, but new work items submitted by those already submitted work items may still be in live state when returning from flush_workqueue(). For the extreme case, pciehp driver may expierence following calling path: 1) pcie_isr() -> pciehp_handle_xxx() -> queue_interrupt_event()->queue_work() 2) interrupt_event_handler() -> handle_button_press_event() -> queue_delayed_work() 3) pciehp_queue_pushbutton_work() -> queue_work() So enhance pcie_cleanup_slot() to correctly flush workqueue when destroying PCIe hotplug controller. Signed-off-by: Jiang Liu Reviewed-by: Kenji Kaneshige --- drivers/pci/hotplug/pciehp_hpc.c | 14 +++++++++++++- 1 files changed, 13 insertions(+), 1 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index a960fae..98b775f 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -889,8 +889,20 @@ static int pcie_init_slot(struct controller *ctrl) static void pcie_cleanup_slot(struct controller *ctrl) { struct slot *slot = ctrl->slot; - cancel_delayed_work(&slot->work); + + /* + * Following workqueue flushing logic is to deal with the special + * call path: + * 1) pcie_isr() -> pciehp_handle_xxx() -> + * queue_interrupt_event(pciehp_wq_event)->queue_work(pciehp_wq) + * 2) interrupt_event_handler() -> handle_button_press_event() -> + * queue_delayed_work(pciehp_wq) + * 3) pciehp_queue_pushbutton_work() -> queue_work(pciehp_wq) + */ flush_workqueue(pciehp_wq); + cancel_delayed_work_sync(&slot->work); + flush_workqueue(pciehp_wq); + kfree(slot); } -- 1.7.5.4