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);
+        }
 }