From patchwork Thu Nov 8 18:07:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 10674817 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 1AD6914E2 for ; Thu, 8 Nov 2018 18:07:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C7CC2DE66 for ; Thu, 8 Nov 2018 18:07:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0032A2DE5F; Thu, 8 Nov 2018 18:07:09 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6DCCA2DF1D for ; Thu, 8 Nov 2018 18:07:08 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 634462118DC4E; Thu, 8 Nov 2018 10:07:08 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=192.55.52.43; helo=mga05.intel.com; envelope-from=alexander.h.duyck@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id A2D9D2118DC4D for ; Thu, 8 Nov 2018 10:07:06 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Nov 2018 10:07:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,480,1534834800"; d="scan'208";a="106592079" Received: from ahduyck-desk1.jf.intel.com ([10.7.198.76]) by orsmga001.jf.intel.com with ESMTP; 08 Nov 2018 10:07:06 -0800 Subject: [driver-core PATCH v6 5/9] driver core: Establish clear order of operations for deferred probe and remove From: Alexander Duyck To: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Date: Thu, 08 Nov 2018 10:07:06 -0800 Message-ID: <154170042611.12967.14256799141542560553.stgit@ahduyck-desk1.jf.intel.com> In-Reply-To: <154170028986.12967.2108024712555179678.stgit@ahduyck-desk1.jf.intel.com> References: <154170028986.12967.2108024712555179678.stgit@ahduyck-desk1.jf.intel.com> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: len.brown@intel.com, bvanassche@acm.org, linux-pm@vger.kernel.org, alexander.h.duyck@linux.intel.com, rafael@kernel.org, jiangshanlai@gmail.com, linux-nvdimm@lists.01.org, pavel@ucw.cz, zwisler@kernel.org, tj@kernel.org, akpm@linux-foundation.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Add an additional bit flag to the device struct named async_probe. This additional flag allows us to guarantee ordering between probe and remove operations. This allows us to guarantee that if we execute a remove operation or a driver load attempt on a given interface it will not attempt to update the driver member asynchronously following the earlier operation. Previously this guarantee was not present and could result in us attempting to remove a driver from an interface only to have it show up later when it is asynchronously loaded. One change I made in addition is I replaced the use of "bool X:1" to define the bitfield to a "u8 X:1" setup in order to resolve some checkpatch warnings. Signed-off-by: Alexander Duyck Reviewed-by: Bart Van Assche --- drivers/base/dd.c | 104 +++++++++++++++++++++++++++--------------------- include/linux/device.h | 3 + 2 files changed, 62 insertions(+), 45 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index e74cefeb5b69..ed19cf0d6f9a 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -472,6 +472,8 @@ static int really_probe(struct device *dev, struct device_driver *drv) drv->bus->name, __func__, drv->name, dev_name(dev)); WARN_ON(!list_empty(&dev->devres_head)); + /* clear async_probe flag as we are no longer deferring driver load */ + dev->async_probe = false; re_probe: dev->driver = drv; @@ -771,6 +773,10 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) device_lock(dev); + /* nothing to do if async_probe has been cleared */ + if (!dev->async_probe) + goto out_unlock; + if (dev->parent) pm_runtime_get_sync(dev->parent); @@ -781,7 +787,7 @@ 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); @@ -826,6 +832,7 @@ static int __device_attach(struct device *dev, bool allow_async) */ dev_dbg(dev, "scheduling asynchronous probe\n"); get_device(dev); + dev->async_probe = true; async_schedule(__device_attach_async_helper, dev); } else { pm_request_idle(dev); @@ -971,62 +978,69 @@ EXPORT_SYMBOL_GPL(driver_attach); */ static void __device_release_driver(struct device *dev, struct device *parent) { - struct device_driver *drv; + struct device_driver *drv = dev->driver; - drv = dev->driver; - if (drv) { - while (device_links_busy(dev)) { - __device_driver_unlock(dev, parent); + /* + * In the event that we are asked to release the driver on an + * interface that is still waiting on a probe we can just terminate + * the probe by setting async_probe to false. When the async call + * is finally completed it will see this state and just exit. + */ + dev->async_probe = false; + if (!drv) + return; - device_links_unbind_consumers(dev); + while (device_links_busy(dev)) { + __device_driver_unlock(dev, parent); - __device_driver_lock(dev, parent); - /* - * A concurrent invocation of the same function might - * have released the driver successfully while this one - * was waiting, so check for that. - */ - if (dev->driver != drv) - return; - } + device_links_unbind_consumers(dev); - pm_runtime_get_sync(dev); - pm_runtime_clean_up_links(dev); + __device_driver_lock(dev, parent); + /* + * A concurrent invocation of the same function might + * have released the driver successfully while this one + * was waiting, so check for that. + */ + if (dev->driver != drv) + return; + } - driver_sysfs_remove(dev); + pm_runtime_get_sync(dev); + pm_runtime_clean_up_links(dev); - if (dev->bus) - blocking_notifier_call_chain(&dev->bus->p->bus_notifier, - BUS_NOTIFY_UNBIND_DRIVER, - dev); + driver_sysfs_remove(dev); - pm_runtime_put_sync(dev); + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->p->bus_notifier, + BUS_NOTIFY_UNBIND_DRIVER, + dev); - if (dev->bus && dev->bus->remove) - dev->bus->remove(dev); - else if (drv->remove) - drv->remove(dev); + pm_runtime_put_sync(dev); - device_links_driver_cleanup(dev); - arch_teardown_dma_ops(dev); + if (dev->bus && dev->bus->remove) + dev->bus->remove(dev); + else if (drv->remove) + drv->remove(dev); - devres_release_all(dev); - dev->driver = NULL; - dev_set_drvdata(dev, NULL); - if (dev->pm_domain && dev->pm_domain->dismiss) - dev->pm_domain->dismiss(dev); - pm_runtime_reinit(dev); - dev_pm_set_driver_flags(dev, 0); + device_links_driver_cleanup(dev); + arch_teardown_dma_ops(dev); + + devres_release_all(dev); + dev->driver = NULL; + dev_set_drvdata(dev, NULL); + if (dev->pm_domain && dev->pm_domain->dismiss) + dev->pm_domain->dismiss(dev); + pm_runtime_reinit(dev); + dev_pm_set_driver_flags(dev, 0); - klist_remove(&dev->p->knode_driver); - device_pm_check_callbacks(dev); - if (dev->bus) - blocking_notifier_call_chain(&dev->bus->p->bus_notifier, - BUS_NOTIFY_UNBOUND_DRIVER, - dev); + klist_remove(&dev->p->knode_driver); + device_pm_check_callbacks(dev); + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->p->bus_notifier, + BUS_NOTIFY_UNBOUND_DRIVER, + dev); - kobject_uevent(&dev->kobj, KOBJ_UNBIND); - } + kobject_uevent(&dev->kobj, KOBJ_UNBIND); } void device_release_driver_internal(struct device *dev, diff --git a/include/linux/device.h b/include/linux/device.h index 1b25c7a43f4c..4d2eb2c74149 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -957,6 +957,8 @@ struct dev_links_info { * device. * @dma_coherent: this particular device is dma coherent, even if the * architecture supports non-coherent devices. + * @async_probe: This device has an asynchronous probe event pending. Should + * only be updated while holding device lock. * * 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 +1053,7 @@ struct device { defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) bool dma_coherent:1; #endif + bool async_probe:1; }; static inline struct device *kobj_to_dev(struct kobject *kobj)