USB: Export URB statistics for powertop

powertop currently tracks interrupts generated by uhci, ehci, and ohci,
but it has no way of telling which USB device to blame USB bus activity on.
This patch exports the number of URBs that are submitted for a given device.
Cat the file 'urbnum' in /sys/bus/usb/devices/.../

Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 2c79aa6ca2b..3dd997df850 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1176,6 +1176,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
          */
         usb_get_urb(urb);
         atomic_inc(&urb->use_count);
+        atomic_inc(&urb->dev->urbnum);
         usbmon_urb_submit(&hcd->self, urb);
 
         /* NOTE requirements on root-hub callers (usbfs and the hub
@@ -1197,6 +1198,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
                 urb->hcpriv = NULL;
                 INIT_LIST_HEAD(&urb->urb_list);
                 atomic_dec(&urb->use_count);
+                atomic_dec(&urb->dev->urbnum);
                 if (urb->reject)
                         wake_up(&usb_kill_urb_queue);
                 usb_put_urb(urb);