diff options
| -rw-r--r-- | drivers/base/dd.c | 51 |
1 files changed, 38 insertions, 13 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 8510918109e0..eab2030c506d 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -177,41 +177,66 @@ void driver_attach(struct device_driver * drv) * @dev: device. * * Manually detach device from driver. - * Note that this is called without incrementing the bus - * reference count nor taking the bus's rwsem. Be sure that - * those are accounted for before calling this function. + * + * __device_release_driver() must be called with @dev->sem held. */ -void device_release_driver(struct device * dev) + +static void __device_release_driver(struct device * dev) { struct device_driver * drv; - down(&dev->sem); - if (dev->driver) { - drv = dev->driver; + drv = dev->driver; + if (drv) { + get_driver(drv); sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); sysfs_remove_link(&dev->kobj, "driver"); - klist_del(&dev->knode_driver); + klist_remove(&dev->knode_driver); if (drv->remove) drv->remove(dev); dev->driver = NULL; + put_driver(drv); } - up(&dev->sem); } -static int __remove_driver(struct device * dev, void * unused) +void device_release_driver(struct device * dev) { - device_release_driver(dev); - return 0; + /* + * If anyone calls device_release_driver() recursively from + * within their ->remove callback for the same device, they + * will deadlock right here. + */ + down(&dev->sem); + __device_release_driver(dev); + up(&dev->sem); } + /** * driver_detach - detach driver from all devices it controls. * @drv: driver. */ void driver_detach(struct device_driver * drv) { - driver_for_each_device(drv, NULL, NULL, __remove_driver); + struct device * dev; + + for (;;) { + spin_lock_irq(&drv->klist_devices.k_lock); + if (list_empty(&drv->klist_devices.k_list)) { + spin_unlock_irq(&drv->klist_devices.k_lock); + break; + } + dev = list_entry(drv->klist_devices.k_list.prev, + struct device, knode_driver.n_node); + get_device(dev); + spin_unlock_irq(&drv->klist_devices.k_lock); + + down(&dev->sem); + if (dev->driver == drv) + __device_release_driver(dev); + up(&dev->sem); + put_device(dev); + } } |