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 <[email protected]> --- 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) _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
