rblkdev
static int backend_open(struct rblkdev *, const char *);
static int backend_close(struct rblkdev *);
struct rblkdev *rblk;
struct rblkdev *rblk;
struct rblkdev *rblk;
backend_open(struct rblkdev *rblk, const char *path)
backend_close(struct rblkdev *rblk)
struct rblkdev *rblk = &minors[minor(dev)];
struct rblkdev *rblk = &minors[dmin];
struct rblkdev *rblk = &minors[minor(bp->b_dev)];