DM_DEV_WAIT_CMD  1680 drivers/md/dm-ioctl.c 		{DM_DEV_WAIT_CMD, 0, dev_wait},
DM_DEV_WAIT_CMD   260 include/uapi/linux/dm-ioctl.h #define DM_DEV_WAIT      _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)