msync & MS_INVALIDATE question

The man page I have for msync(MS_INVALIDATE) says it should invalidate all other mappings. I.e. get all other mappings.

The implementation does something quite different, that is related to only the present mapping.

Was this a pure documentation bug. Was MS_INVALIDATE not implemented correctly because of no reverse maps? Or is something else going on here?

I know in the context of MAP_SHARED invalidating other mappings seems like a reasonable proposition.

Eric