[patch]a lockless method to alter pm count

Hi,

some drivers'll need a lockless method to alter the pm count in order
to take locks by themselves in correct order.

	Regards
		Oliver

Signed-off-by: Oliver Neukum <[email protected]>
-- 

--- a/include/linux/usb.h	2007-04-24 14:12:23.000000000 +0200
+++ b/include/linux/usb.h	2007-04-24 14:25:13.000000000 +0200
@@ -424,6 +424,8 @@ extern struct usb_device *usb_find_devic
 extern int usb_autopm_set_interface(struct usb_interface *intf);
 extern int usb_autopm_get_interface(struct usb_interface *intf);
 extern void usb_autopm_put_interface(struct usb_interface *intf);
+extern int usb_autopm_do_interface(struct usb_interface *intf, int inc_usage_cnt);
+extern int __usb_autopm_do_interface(struct usb_interface *intf, int inc_usage_cnt);
 
 static inline void usb_autopm_enable(struct usb_interface *intf)
 {
@@ -451,6 +453,11 @@ static inline void usb_autopm_enable(str
 { }
 static inline void usb_autopm_disable(struct usb_interface *intf)
 { }
+extern int usb_autopm_do_interface(struct usb_interface *intf, int inc_usage_cnt);
+{ return 0; }
+extern int __usb_autopm_do_interface(struct usb_interface *intf, int inc_usage_cnt);
+{ return 0; }
+
 #endif
 
 /*-------------------------------------------------------------------------*/
--- a/drivers/usb/core/driver.c	2007-04-24 13:48:42.000000000 +0200
+++ b/drivers/usb/core/driver.c	2007-04-24 14:20:45.000000000 +0200
@@ -1276,13 +1276,12 @@ int usb_autoresume_device(struct usb_dev
 /* Internal routine to adjust an interface's usage counter and change
  * its device's autosuspend state.
  */
-static int usb_autopm_do_interface(struct usb_interface *intf,
+int __usb_autopm_do_interface(struct usb_interface *intf,
 		int inc_usage_cnt)
 {
 	struct usb_device	*udev = interface_to_usbdev(intf);
 	int			status = 0;
 
-	usb_pm_lock(udev);
 	if (intf->condition == USB_INTERFACE_UNBOUND)
 		status = -ENODEV;
 	else {
@@ -1296,10 +1295,23 @@ static int usb_autopm_do_interface(struc
 			queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
 					udev->autosuspend_delay);
 	}
-	usb_pm_unlock(udev);
 	return status;
 }
+EXPORT_SYMBOL_GPL(__usb_autopm_do_interface);
+
+int usb_autopm_do_interface(struct usb_interface *intf,
+		int inc_usage_cnt)
+{
+	int r;
+	struct usb_device	*udev = interface_to_usbdev(intf);
 
+	usb_pm_lock(udev);
+	r = __usb_autopm_do_interface(intf, inc_usage_cnt);
+	usb_pm_unlock(udev);
+
+	return r;
+}
+EXPORT_SYMBOL_GPL(usb_autopm_do_interface);
 /**
  * usb_autopm_put_interface - decrement a USB interface's PM-usage counter
  * @intf: the usb_interface whose counter should be decremented


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