From patchwork Wed Dec 5 17:25:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 10714675 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 390F0109C for ; Wed, 5 Dec 2018 17:25:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 284E32E1E7 for ; Wed, 5 Dec 2018 17:25:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1C0CB2E1EE; Wed, 5 Dec 2018 17:25:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AA9472E1E7 for ; Wed, 5 Dec 2018 17:25:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728440AbeLERZZ (ORCPT ); Wed, 5 Dec 2018 12:25:25 -0500 Received: from mga11.intel.com ([192.55.52.93]:30644 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728359AbeLERZY (ORCPT ); Wed, 5 Dec 2018 12:25:24 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Dec 2018 09:25:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,318,1539673200"; d="scan'208";a="116247768" Received: from ahduyck-desk1.jf.intel.com ([10.7.198.76]) by orsmga001.jf.intel.com with ESMTP; 05 Dec 2018 09:25:24 -0800 Subject: [driver-core PATCH v8 2/9] driver core: Establish order of operations for device_add and device_del via bitflag From: Alexander Duyck To: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Cc: mcgrof@kernel.org, linux-nvdimm@lists.01.org, tj@kernel.org, akpm@linux-foundation.org, linux-pm@vger.kernel.org, jiangshanlai@gmail.com, rafael@kernel.org, len.brown@intel.com, pavel@ucw.cz, zwisler@kernel.org, dan.j.williams@intel.com, dave.jiang@intel.com, bvanassche@acm.org, alexander.h.duyck@linux.intel.com Date: Wed, 05 Dec 2018 09:25:24 -0800 Message-ID: <154403072403.11544.10419282512791659652.stgit@ahduyck-desk1.jf.intel.com> In-Reply-To: <154403054034.11544.3978949383914046587.stgit@ahduyck-desk1.jf.intel.com> References: <154403054034.11544.3978949383914046587.stgit@ahduyck-desk1.jf.intel.com> User-Agent: StGit/unknown-version MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add an additional bit flag to the device struct named "dead". This additional flag provides a guarantee that when a device_del is executed on a given interface an async worker will not attempt to attach the driver following the earlier device_del call. Previously this guarantee was not present and could result in the device_del call attempting to remove a driver from an interface only to have the async worker attempt to probe the driver later when it finally completes the asynchronous probe call. Signed-off-by: Alexander Duyck --- drivers/base/core.c | 11 +++++++++++ drivers/base/dd.c | 8 ++++++-- include/linux/device.h | 5 +++++ 3 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index f3e6ca4170b4..70358327303b 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2075,6 +2075,17 @@ void device_del(struct device *dev) struct kobject *glue_dir = NULL; struct class_interface *class_intf; + /* + * Hold the device lock and set the "dead" flag to guarantee that + * the update behavior is consistent with the other bitfields near + * it and that we cannot have an asynchronous probe routine trying + * to run while we are tearing out the bus/class/sysfs from + * underneath the device. + */ + device_lock(dev); + dev->dead = true; + device_unlock(dev); + /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 88713f182086..3bb8c3e0f3da 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -774,6 +774,10 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) device_lock(dev); + /* device is or has been removed from the bus, just bail out */ + if (dev->dead) + goto out_unlock; + if (dev->parent) pm_runtime_get_sync(dev->parent); @@ -784,7 +788,7 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) if (dev->parent) pm_runtime_put(dev->parent); - +out_unlock: device_unlock(dev); put_device(dev); @@ -897,7 +901,7 @@ static int __driver_attach(struct device *dev, void *data) if (dev->parent && dev->bus->need_parent_lock) device_lock(dev->parent); device_lock(dev); - if (!dev->driver) + if (!dev->dead && !dev->driver) driver_probe_device(drv, dev); device_unlock(dev); if (dev->parent && dev->bus->need_parent_lock) diff --git a/include/linux/device.h b/include/linux/device.h index 4921a6192f6b..393704e5b602 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -957,6 +957,10 @@ struct dev_links_info { * device. * @dma_coherent: this particular device is dma coherent, even if the * architecture supports non-coherent devices. + * @dead: This device is currently either in the process of or has + * been removed from the system. Any asynchronous events + * scheduled for this device should exit without taking any + * action. * * At the lowest level, every device in a Linux system is represented by an * instance of struct device. The device structure contains the information @@ -1051,6 +1055,7 @@ struct device { defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) bool dma_coherent:1; #endif + bool dead:1; }; static inline struct device *kobj_to_dev(struct kobject *kobj)