_LINUX32_IOC_SIZESHIFT
#define _LINUX32_IOC_DIRSHIFT (_LINUX32_IOC_SIZESHIFT + _LINUX32_IOC_SIZEBITS)
((size) << _LINUX32_IOC_SIZESHIFT) | \
(((nr) >> _LINUX32_IOC_SIZESHIFT) & _LINUX32_IOC_SIZEMASK)