[PATCH] USB: Remove USB private semaphore

This patch (as605) removes the private udev->serialize semaphore,
relying instead on the locking provided by the embedded struct device's
semaphore.  The changes are confined to the core, except that the
usb_trylock_device routine now uses the return convention of
down_trylock rather than down_read_trylock (they return opposite values
for no good reason).

A couple of other associated changes are included as well:

	Now that we aren't concerned about HCDs that avoid using the
	hcd glue layer, usb_disconnect no longer needs to acquire the
	usb_bus_lock -- that can be done by usb_remove_hcd where it
	belongs.

	Devices aren't locked over the same scope of code in
	usb_new_device and hub_port_connect_change as they used to be.
	This shouldn't cause any trouble.

Along with the preceding driver core patch, this needs a lot of testing.

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

1 files changed, 4 insertions, 5 deletions

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 2714814..46dc042 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -329,8 +329,6 @@ struct usb_device {
 	struct usb_tt	*tt; 		/* low/full speed dev, highspeed hub */
 	int		ttport;		/* device port on that tt hub */
 
-	struct semaphore serialize;
-
 	unsigned int toggle[2];		/* one bit for each endpoint
 					 * ([0] = IN, [1] = OUT) */
 
@@ -377,11 +375,12 @@ struct usb_device {
 extern struct usb_device *usb_get_dev(struct usb_device *dev);
 extern void usb_put_dev(struct usb_device *dev);
 
-extern void usb_lock_device(struct usb_device *udev);
-extern int usb_trylock_device(struct usb_device *udev);
+/* USB device locking */
+#define usb_lock_device(udev)		down(&(udev)->dev.sem)
+#define usb_unlock_device(udev)		up(&(udev)->dev.sem)
+#define usb_trylock_device(udev)	down_trylock(&(udev)->dev.sem)
 extern int usb_lock_device_for_reset(struct usb_device *udev,
 		struct usb_interface *iface);
-extern void usb_unlock_device(struct usb_device *udev);
 
 /* USB port reset for device reinitialization */
 extern int usb_reset_device(struct usb_device *dev);