usbcore: store each usb_device's level in the tree

This patch (as778) adds a field to struct usb_device to store the
device's level in the USB tree.  In itself this number isn't really
important.  But the overhead is very low, and in a later patch it will
be used for preventing bogus warnings from the lockdep checker.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 2 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index f5adce049b35..78e910b2046c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2414,6 +2414,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
                 usb_set_device_state(udev, USB_STATE_POWERED);
                 udev->speed = USB_SPEED_UNKNOWN;
                 udev->bus_mA = hub->mA_per_port;
+                udev->level = hdev->level + 1;
 
                 /* set the address */
                 choose_address(udev);
diff --git a/include/linux/usb.h b/include/linux/usb.h
index c66303285a45..df5c93eb3ce9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -348,6 +348,7 @@ struct usb_device {
 
         unsigned short bus_mA;          /* Current available from the bus */
         u8 portnum;                     /* Parent port number (origin 1) */
+        u8 level;                       /* Number of USB hub ancestors */
 
         int have_langid;                /* whether string_langid is valid */
         int string_langid;              /* language ID for strings */