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>

1 files changed, 18 insertions, 10 deletions

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 4e2c6df8d3cc..932f68e6ad19 100644
--- 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);