struct ums {
int (*read_sector)(struct ums *ums_dev,
ulong start, lbaint_t blkcnt, void *buf);
int (*write_sector)(struct ums *ums_dev,
ulong start, lbaint_t blkcnt, const void *buf);
struct ums {
int (*read_sector)(struct ums *ums_dev,
ulong start, lbaint_t blkcnt, void *buf);
int (*write_sector)(struct ums *ums_dev,
ulong start, lbaint_t blkcnt, const void *buf);