commit 3451a495ef244a88ed6317a035299d835554d579 upstream.
Add an additional bit flag to the device_private 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.
One additional change added was that I pulled the check for dev->driver out of the __device_attach_driver call and instead placed it in the __device_attach_async_helper call. This was motivated by the fact that the only other caller of this, __device_attach, had already taken the device_lock() and checked for dev->driver. Instead of testing for this twice in this path it makes more sense to just consolidate the dev->dead and dev->driver checks together into one set of checks.
Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Alexander Duyck alexander.h.duyck@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/base.h | 4 ++++ drivers/base/core.c | 11 +++++++++++ drivers/base/dd.c | 22 +++++++++++----------- 3 files changed, 26 insertions(+), 11 deletions(-)
diff --git a/drivers/base/base.h b/drivers/base/base.h index 7a419a7a6235b..559b047de9f75 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -66,6 +66,9 @@ struct driver_private { * probed first. * @device - pointer back to the struct device that this structure is * associated with. + * @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. * * Nothing outside of the driver core should ever touch these fields. */ @@ -76,6 +79,7 @@ struct device_private { struct klist_node knode_bus; struct list_head deferred_probe; struct device *device; + u8 dead:1; }; #define to_device_private_parent(obj) \ container_of(obj, struct device_private, knode_parent) diff --git a/drivers/base/core.c b/drivers/base/core.c index 92e2c32c22270..37a90d72f3736 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2050,6 +2050,17 @@ 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->p->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 d48b310c47603..11d24a552ee49 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -725,15 +725,6 @@ static int __device_attach_driver(struct device_driver *drv, void *_data) bool async_allowed; int ret;
- /* - * Check if device has already been claimed. This may - * happen with driver loading, device discovery/registration, - * and deferred probe processing happens all at once with - * multiple threads. - */ - if (dev->driver) - return -EBUSY; - ret = driver_match_device(drv, dev); if (ret == 0) { /* no match */ @@ -768,6 +759,15 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
device_lock(dev);
+ /* + * Check if device has already been removed or claimed. This may + * happen with driver loading, device discovery/registration, + * and deferred probe processing happens all at once with + * multiple threads. + */ + if (dev->p->dead || dev->driver) + goto out_unlock; + if (dev->parent) pm_runtime_get_sync(dev->parent);
@@ -778,7 +778,7 @@ 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); @@ -891,7 +891,7 @@ 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->p->dead && !dev->driver) driver_probe_device(drv, dev); device_unlock(dev); if (dev->parent && dev->bus->need_parent_lock)