elv_register_queue  993 block/blk-sysfs.c 		ret = elv_register_queue(q, false);
elv_register_queue  203 block/blk.h    int elv_register_queue(struct request_queue *q, bool uevent);
elv_register_queue  601 block/elevator.c 		ret = elv_register_queue(q, true);