Revert "USB: Close usb_find_interface race"

This reverts commit a2582bd478c13c574d4c16ef1209d333f2a25935.

It turned out to be buggy and broke USB printers from working.

Cc: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 4e2c6df8d3cc6b0427f3d7ffa645c0073531490e..932f68e6ad194fc31f803f8d92ef1ddd42b8188c 100644 (file)
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -167,17 +167,24 @@ struct usb_host_interface *usb_altnum_to_altsetting(
 }
 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
 
+struct find_interface_arg {
+       int minor;
+       struct usb_interface *interface;
+};
+
 static int __find_interface(struct device *dev, void *data)
 {
-       int *minor = data;
+       struct find_interface_arg *arg = data;
        struct usb_interface *intf;
 
        if (!is_usb_interface(dev))
                return 0;
 
        intf = to_usb_interface(dev);
-       if (intf->minor != -1 && intf->minor == *minor)
+       if (intf->minor != -1 && intf->minor == arg->minor) {
+               arg->interface = intf;
                return 1;
+       }
        return 0;
 }
 
@@ -186,20 +193,21 @@ static int __find_interface(struct device *dev, void *data)
  * @drv: the driver whose current configuration is considered
  * @minor: the minor number of the desired device
  *
- * This walks the bus device list and returns a pointer to the interface
+ * This walks the driver device list and returns a pointer to the interface
  * with the matching minor.  Note, this only works for devices that share the
  * USB major number.
  */
 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
 {
-       struct device *dev;
-
-       dev = bus_find_device(&usb_bus_type, NULL, &minor, __find_interface);
-
-       /* Drop reference count from bus_find_device */
-       put_device(dev);
+       struct find_interface_arg argb;
+       int retval;
 
-       return dev ? to_usb_interface(dev) : NULL;
+       argb.minor = minor;
+       argb.interface = NULL;
+       /* eat the error, it will be in argb.interface */
+       retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
+                                       __find_interface);
+       return argb.interface;
 }
 EXPORT_SYMBOL_GPL(usb_find_interface);