From patchwork Thu Jan 10 03:22:58 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yijing Wang X-Patchwork-Id: 1958411 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 2BF7A3FC5A for ; Thu, 10 Jan 2013 03:23:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932724Ab3AJDXc (ORCPT ); Wed, 9 Jan 2013 22:23:32 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:57375 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932720Ab3AJDXc (ORCPT ); Wed, 9 Jan 2013 22:23:32 -0500 Received: from 172.24.2.119 (EHLO szxeml213-edg.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.4-GA FastPath queued) with ESMTP id AVR35965; Thu, 10 Jan 2013 11:23:22 +0800 (CST) Received: from SZXEML408-HUB.china.huawei.com (10.82.67.95) by szxeml213-edg.china.huawei.com (172.24.2.30) with Microsoft SMTP Server (TLS) id 14.1.323.3; Thu, 10 Jan 2013 11:23:21 +0800 Received: from localhost (10.135.76.69) by szxeml408-hub.china.huawei.com (10.82.67.95) with Microsoft SMTP Server id 14.1.323.3; Thu, 10 Jan 2013 11:23:14 +0800 From: Yijing Wang To: Bjorn Helgaas CC: Kenji Kaneshige , Yinghai Lu , , Hanjun Guo , , Yijing Wang Subject: [PATCH 1/2] PCI, pciehp: make every slot have its own workqueue to avoid deadlock Date: Thu, 10 Jan 2013 11:22:58 +0800 Message-ID: <1357788179-9764-1-git-send-email-wangyijing@huawei.com> X-Mailer: git-send-email 1.7.11.msysgit.1 MIME-Version: 1.0 X-Originating-IP: [10.135.76.69] X-CFilter-Loop: Reflected Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Currently, pciehp use global pciehp_wq to handle hotplug event from hardware. Hot remove path will be blocked if a hotplug slot connected a IO-BOX(composed of PCIe Switch and some slots which support hotplug). Because The hot removed work was queued into pciehp_wq. But in the hot-remove path, pciehp driver would flush pciehp_wq when the pcie port(support pciehp) was removed. In this case the hot-remove path blocked. This patch remove the global pciehp_wq and create a new workqueue for every slot to avoid above problem. call path: 1. Hot-removal request comes to slot A(eg. 0000:40:07.0 as bellow) 2. Pciehp driver queue hot-remove work into global workqueue "pciehp_wq" 3. Hot-remove work call pci_stop_and_remove_bus_device() to remove child devices. 4. Unregister and remove Pcie port device slot B(eg. 0000:47:15.0). 5. To remove pcie port device, flush_workqueue(pciehp_wq) will be called. 6. Deaklock <== hot-removal work is in progress. -+-[0000:40]-+-00.0-[0000:41]-- | +-01.0-[0000:42]--+-00.0 Intel Corporation 82576 Gigabit Network Connection | | \-00.1 Intel Corporation 82576 Gigabit Network Connection | +-03.0-[0000:43]----00.0 LSI Logic / Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS | +-04.0-[0000:44]-- | +-05.0-[0000:45]-- | +-07.0-[0000:46-4f]----00.0-[0000:47-4f]--+-04.0-[0000:48-49]----00.0-[0000:49]-- | |(slot A) +-08.0-[0000:4a]-- | | +-09.0-[0000:4b]-- | | +-10.0-[0000:4c]-- | | +-11.0-[0000:4d]-- | | +-14.0-[0000:4e]-- | | \-15.0-[0000:4f]--+-00.0 Intel Corporation 82576 Gigabit Network Connection | | (slot B) \-00.1 Intel Corporation 82576 Gigabit Network Connection Reviewed-by: Kenji Kaneshige Signed-off-by: Yijing Wang --- drivers/pci/hotplug/pciehp.h | 2 +- drivers/pci/hotplug/pciehp_core.c | 11 ++--------- drivers/pci/hotplug/pciehp_ctrl.c | 8 ++++---- drivers/pci/hotplug/pciehp_hpc.c | 11 ++++++++++- 4 files changed, 17 insertions(+), 15 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 26ffd3e..2c113de 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -44,7 +44,6 @@ extern bool pciehp_poll_mode; extern int pciehp_poll_time; extern bool pciehp_debug; extern bool pciehp_force; -extern struct workqueue_struct *pciehp_wq; #define dbg(format, arg...) \ do { \ @@ -78,6 +77,7 @@ struct slot { struct hotplug_slot *hotplug_slot; struct delayed_work work; /* work for button event */ struct mutex lock; + struct workqueue_struct *wq; }; struct event_info { diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c index 916bf4f..939bd1d 100644 --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -42,7 +42,6 @@ bool pciehp_debug; bool pciehp_poll_mode; int pciehp_poll_time; bool pciehp_force; -struct workqueue_struct *pciehp_wq; #define DRIVER_VERSION "0.4" #define DRIVER_AUTHOR "Dan Zink , Greg Kroah-Hartman , Dely Sy " @@ -340,18 +339,13 @@ static int __init pcied_init(void) { int retval = 0; - pciehp_wq = alloc_workqueue("pciehp", 0, 0); - if (!pciehp_wq) - return -ENOMEM; - pciehp_firmware_init(); retval = pcie_port_service_register(&hpdriver_portdrv); dbg("pcie_port_service_register = %d\n", retval); info(DRIVER_DESC " version: " DRIVER_VERSION "\n"); - if (retval) { - destroy_workqueue(pciehp_wq); + if (retval) dbg("Failure to register service\n"); - } + return retval; } @@ -359,7 +353,6 @@ static void __exit pcied_cleanup(void) { dbg("unload_pciehpd()\n"); pcie_port_service_unregister(&hpdriver_portdrv); - destroy_workqueue(pciehp_wq); info(DRIVER_DESC " version: " DRIVER_VERSION " unloaded\n"); } diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index 27f4429..38f0186 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -49,7 +49,7 @@ static int queue_interrupt_event(struct slot *p_slot, u32 event_type) info->p_slot = p_slot; INIT_WORK(&info->work, interrupt_event_handler); - queue_work(pciehp_wq, &info->work); + queue_work(p_slot->wq, &info->work); return 0; } @@ -344,7 +344,7 @@ void pciehp_queue_pushbutton_work(struct work_struct *work) kfree(info); goto out; } - queue_work(pciehp_wq, &info->work); + queue_work(p_slot->wq, &info->work); out: mutex_unlock(&p_slot->lock); } @@ -377,7 +377,7 @@ static void handle_button_press_event(struct slot *p_slot) if (ATTN_LED(ctrl)) pciehp_set_attention_status(p_slot, 0); - queue_delayed_work(pciehp_wq, &p_slot->work, 5*HZ); + queue_delayed_work(p_slot->wq, &p_slot->work, 5*HZ); break; case BLINKINGOFF_STATE: case BLINKINGON_STATE: @@ -439,7 +439,7 @@ static void handle_surprise_event(struct slot *p_slot) else p_slot->state = POWERON_STATE; - queue_work(pciehp_wq, &info->work); + queue_work(p_slot->wq, &info->work); } static void interrupt_event_handler(struct work_struct *work) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 13b2eaf..5127f3f 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -773,23 +773,32 @@ static void pcie_shutdown_notification(struct controller *ctrl) static int pcie_init_slot(struct controller *ctrl) { struct slot *slot; + char name[32]; slot = kzalloc(sizeof(*slot), GFP_KERNEL); if (!slot) return -ENOMEM; + snprintf(name, sizeof(name), "pciehp-%u", PSN(ctrl)); + slot->wq = alloc_workqueue(name, 0, 0); + if (!slot->wq) + goto abort; + slot->ctrl = ctrl; mutex_init(&slot->lock); INIT_DELAYED_WORK(&slot->work, pciehp_queue_pushbutton_work); ctrl->slot = slot; return 0; +abort: + kfree(slot); + return -ENOMEM; } static void pcie_cleanup_slot(struct controller *ctrl) { struct slot *slot = ctrl->slot; cancel_delayed_work(&slot->work); - flush_workqueue(pciehp_wq); + destroy_workqueue(slot->wq); kfree(slot); }