Re: [PATCH 01/19] mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags

How about the following incremental update? It allows ->mmap_validate()
to be used as a full replacement for ->mmap() and it limits the error
code freedom to a centralized mmap_status_errno() routine:

Nah - my earlier comment was simply misinformed because I didn't
read the whole patch and the _validate name mislead me.

So I think the current calling conventions are ok, I'd just like a
better name (mmap_flags maybe?) and avoid the need the file system
also has to implement ->mmap.