blk_free_devt    1327 block/genhd.c  	blk_free_devt(dev->devt);
blk_free_devt     226 block/partition-generic.c 	blk_free_devt(dev->devt);
blk_free_devt     619 include/linux/genhd.h extern void blk_free_devt(dev_t devt);