Must I implement the vm_operations while rtdm_mmap_to_user function is to be called?

[孙世龙]

Hi,
      Must I implement the vm_operations while
rtdm_mmap_to_user function is to be called?
      Vm_operations is to be executed on the vm_area
of the user memory range, as per the documentation,
https://xenomai.org/documentation/xenomai-3/html/xeno3prm/group__rtdm__util.html#ga819ed9b5bbfd95e4f833c7f70732cebd
.
     I wonder when the vm_operations is to be called
and what function it supplys.When should I
implement the vm_operations.

     Thanks for your attention.