This patch is a slightly revised version of as277c, updated to match the
current source.  The only difference from the older version is that this
makes urb->use_count into an atomic_t, to avoid the overhead of an extra
locking step each time an URB is submitted and given back.  The important
features of this patch are:

	-EPERM added to Documentation/usb/error-codes.txt.

	Failure to use URB_ASYNC_UNLINK with usb_unlink_urb() is
	deprecated in the documentation.

	New ->reject and ->use_count fields added to struct urb.
	The reject field is protected by urb->lock, and locking is
	required only in usb_kill_urb() which doesn't have to be fast.

	Single wait_queue used for all processes waiting inside
	usb_kill_urb().  The wait queue is woken up only when an URB
	is given back with ->reject set.

	usb_rh_status_dequeue() changed to return int.  It looks like
	this function should be declared static; it's not used outside
	the hcd.c file.

	Prototype for unlink_urb() in struct usb_operations is changed
	to include a status code argument.  This is necessary so that
	the different unlink paths can return -ENOENT and -ECONNRESET
	as appropriate.

	Support for synchronous usb_unlink_urb() has been removed;
	such calls are passed to usb_kill_urb().

	Kerneldoc for usb_unlink_urb() is updated.

	usb_kill_urb() added to urb.c.

	hc_simple() host driver is partially updated -- it should
	compile but it won't really work right.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>