CEPH_FRAME_MAX_SEGMENT_COUNT
int fd_lens[CEPH_FRAME_MAX_SEGMENT_COUNT]; /* logical */
int fd_aligns[CEPH_FRAME_MAX_SEGMENT_COUNT];
BUG_ON(desc->fd_seg_cnt > CEPH_FRAME_MAX_SEGMENT_COUNT);
desc->fd_seg_cnt > CEPH_FRAME_MAX_SEGMENT_COUNT) {