[PATCH] driver core: add helper device_is_registered()

add the helper and use it instead of open coding the klist_node_attached() check
(which is a layering violation IMHO)

idea by Alan Stern.

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 10 insertions, 5 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 91ea8e4777f3..dbb3eb0e330b 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -437,7 +437,7 @@ __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
         if (cdev->dev.driver_data) {
                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
                 if (get_device(&gdev->dev)) {
-                        if (klist_node_attached(&gdev->dev.knode_bus))
+                        if (device_is_registered(&gdev->dev))
                                 return gdev;
                         put_device(&gdev->dev);
                 }
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index c47c8052b486..f1fb67fe22a8 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -987,7 +987,7 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
 
                         /* remove this interface if it has been registered */
                         interface = dev->actconfig->interface[i];
-                        if (!klist_node_attached(&interface->dev.knode_bus))
+                        if (!device_is_registered(&interface->dev))
                                 continue;
                         dev_dbg (&dev->dev, "unregistering interface %s\n",
                                 interface->dev.bus_id);
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 087af73a59dd..7d131509e419 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -303,7 +303,7 @@ int usb_driver_claim_interface(struct usb_driver *driver,
         /* if interface was already added, bind now; else let
          * the future device_add() bind it, bypassing probe()
          */
-        if (klist_node_attached(&dev->knode_bus))
+        if (device_is_registered(dev))
                 device_bind_driver(dev);
 
         return 0;
@@ -336,8 +336,8 @@ void usb_driver_release_interface(struct usb_driver *driver,
         if (iface->condition != USB_INTERFACE_BOUND)
                 return;
 
-        /* release only after device_add() */
-        if (klist_node_attached(&dev->knode_bus)) {
+        /* don't release if the interface hasn't been added yet */
+        if (device_is_registered(dev)) {
                 iface->condition = USB_INTERFACE_UNBINDING;
                 device_release_driver(dev);
         }
diff --git a/include/linux/device.h b/include/linux/device.h
index 06e5d42f2c7b..95d607a48f06 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -317,6 +317,11 @@ dev_set_drvdata (struct device *dev, void *data)
         dev->driver_data = data;
 }
 
+static inline int device_is_registered(struct device *dev)
+{
+        return klist_node_attached(&dev->knode_bus);
+}
+
 /*
  * High level routines for use by the bus drivers
  */