int (*bo_unmap)(struct bo *bo, struct vma *vma);
int (*bo_invalidate)(struct bo *bo, struct mapping *mapping);
int (*bo_flush)(struct bo *bo, struct mapping *mapping);
int (*bo_unmap)(struct bo *bo, struct vma *vma);
int (*bo_invalidate)(struct bo *bo, struct mapping *mapping);
int (*bo_flush)(struct bo *bo, struct mapping *mapping);