mdu_disk_info_t    41 include/uapi/linux/raid/md_u.h #define GET_DISK_INFO		_IOR (MD_MAJOR, 0x12, mdu_disk_info_t)
mdu_disk_info_t    47 include/uapi/linux/raid/md_u.h #define ADD_NEW_DISK		_IOW (MD_MAJOR, 0x21, mdu_disk_info_t)