1 files changed, 36 insertions, 5 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index fa601b085eb..29f6af554e7 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -152,7 +152,11 @@ static ssize_t driver_unbind(struct device_driver *drv,
 
         dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
         if (dev && dev->driver == drv) {
+                if (dev->parent)        /* Needed for USB */
+                        down(&dev->parent->sem);
                 device_release_driver(dev);
+                if (dev->parent)
+                        up(&dev->parent->sem);
                 err = count;
         }
         put_device(dev);
@@ -175,9 +179,13 @@ static ssize_t driver_bind(struct device_driver *drv,
 
         dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
         if (dev && dev->driver == NULL) {
+                if (dev->parent)        /* Needed for USB */
+                        down(&dev->parent->sem);
                 down(&dev->sem);
                 err = driver_probe_device(drv, dev);
                 up(&dev->sem);
+                if (dev->parent)
+                        up(&dev->parent->sem);
         }
         put_device(dev);
         put_bus(bus);
@@ -420,6 +428,26 @@ static void driver_remove_attrs(struct bus_type * bus, struct device_driver * dr
         }
 }
 
+#ifdef CONFIG_HOTPLUG
+/*
+ * Thanks to drivers making their tables __devinit, we can't allow manual
+ * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
+ */
+static void add_bind_files(struct device_driver *drv)
+{
+        driver_create_file(drv, &driver_attr_unbind);
+        driver_create_file(drv, &driver_attr_bind);
+}
+
+static void remove_bind_files(struct device_driver *drv)
+{
+        driver_remove_file(drv, &driver_attr_bind);
+        driver_remove_file(drv, &driver_attr_unbind);
+}
+#else
+static inline void add_bind_files(struct device_driver *drv) {}
+static inline void remove_bind_files(struct device_driver *drv) {}
+#endif
 
 /**
  *      bus_add_driver - Add a driver to the bus.
@@ -449,8 +477,7 @@ int bus_add_driver(struct device_driver * drv)
                 module_add_driver(drv->owner, drv);
 
                 driver_add_attrs(bus, drv);
-                driver_create_file(drv, &driver_attr_unbind);
-                driver_create_file(drv, &driver_attr_bind);
+                add_bind_files(drv);
         }
         return error;
 }
@@ -468,8 +495,7 @@ int bus_add_driver(struct device_driver * drv)
 void bus_remove_driver(struct device_driver * drv)
 {
         if (drv->bus) {
-                driver_remove_file(drv, &driver_attr_bind);
-                driver_remove_file(drv, &driver_attr_unbind);
+                remove_bind_files(drv);
                 driver_remove_attrs(drv->bus, drv);
                 klist_remove(&drv->knode_bus);
                 pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
@@ -484,8 +510,13 @@ void bus_remove_driver(struct device_driver * drv)
 /* Helper for bus_rescan_devices's iter */
 static int bus_rescan_devices_helper(struct device *dev, void *data)
 {
-        if (!dev->driver)
+        if (!dev->driver) {
+                if (dev->parent)        /* Needed for USB */
+                        down(&dev->parent->sem);
                 device_attach(dev);
+                if (dev->parent)
+                        up(&dev->parent->sem);
+        }
         return 0;
 }