Two main issues fixed here are:
 - An improper use of in-struct lock to protect an open count
 - Use of urb status for -EINPROGRESS

Also, along the way:
 - Change usb_unlink_urb to usb_kill_urb. Apparently there's no need
   to use usb_unlink_urb whatsoever in this driver, and the old use of
   usb_kill_urb was outright racy (it unlinked and immediately freed).
 - Fix indentation in adu_write. Looks like it was damaged by a script.
 - Vitaly wants -EBUSY on multiply opens.
 - bInterval was taken from a wrong endpoint.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Tested-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>