/**
 * module_exit() - driver exit entry point
 * @x: function to be run when driver is removed
 *
 * module_exit() will wrap the driver clean-up code
 * with cleanup_module() when used with rmmod when
 * the driver is a module.  If the driver is statically
 * compiled into the kernel, module_exit() has no effect.
 * There can only be one per module.
 */
#define module_exit(x)  __exitcall(x);

#define __exitcall(fn)            \
  static exitcall_t __exitcall_##fn __exit_call = fn

typedef void (*exitcall_t)(void);