extern void vfio_group_put_external_user(struct vfio_group *group);
extern struct iommu_group *vfio_file_iommu_group(struct file *file);
extern bool vfio_file_enforced_coherent(struct file *file);
extern void vfio_group_put_external_user(struct vfio_group *group);
extern struct iommu_group *vfio_file_iommu_group(struct file *file);
extern bool vfio_file_enforced_coherent(struct file *file);