1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 3b419c9a1e7e..2b905016664d 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -65,7 +65,8 @@ void device_bind_driver(struct device * dev)
  *      This function returns 1 if a match is found, an error if one
  *      occurs (that is not -ENODEV or -ENXIO), and 0 otherwise.
  *
- *      This function must be called with @dev->sem held.
+ *      This function must be called with @dev->sem held.  When called
+ *      for a USB interface, @dev->parent->sem must be held as well.
  */
 int driver_probe_device(struct device_driver * drv, struct device * dev)
 {
@@ -123,6 +124,8 @@ static int __device_attach(struct device_driver * drv, void * data)
  *
  *      Returns 1 if the device was bound to a driver;
  *      0 if no matching device was found; error code otherwise.
+ *
+ *      When called for a USB interface, @dev->parent->sem must be held.
  */
 int device_attach(struct device * dev)
 {
@@ -152,10 +155,14 @@ static int __driver_attach(struct device * dev, void * data)
          * is an error.
          */
 
+        if (dev->parent)        /* Needed for USB */
+                down(&dev->parent->sem);
         down(&dev->sem);
         if (!dev->driver)
                 driver_probe_device(drv, dev);
         up(&dev->sem);
+        if (dev->parent)
+                up(&dev->parent->sem);
 
         return 0;
 }
@@ -181,6 +188,8 @@ void driver_attach(struct device_driver * drv)
  *      Manually detach device from driver.
  *
  *      __device_release_driver() must be called with @dev->sem held.
+ *      When called for a USB interface, @dev->parent->sem must be held
+ *      as well.
  */
 
 static void __device_release_driver(struct device * dev)
@@ -233,10 +242,14 @@ void driver_detach(struct device_driver * drv)
                 get_device(dev);
                 spin_unlock(&drv->klist_devices.k_lock);
 
+                if (dev->parent)        /* Needed for USB */
+                        down(&dev->parent->sem);
                 down(&dev->sem);
                 if (dev->driver == drv)
                         __device_release_driver(dev);
                 up(&dev->sem);
+                if (dev->parent)
+                        up(&dev->parent->sem);
                 put_device(dev);
         }
 }