#define to_subchannel(n) container_of(n, struct subchannel, dev)
-extern int cio_validate_subchannel (struct subchannel *, struct subchannel_id);
extern int cio_enable_subchannel(struct subchannel *, u32);
extern int cio_disable_subchannel (struct subchannel *);
extern int cio_cancel (struct subchannel *);