Re: [PATCH v4 2/3] mm: introduce MAP_VALIDATE a mechanism for adding new mmap flags

[Christoph Hellwig]

On Sat, Sep 16, 2017 at 08:44:14PM -0700, Dan Williams wrote:
> So it wasn't all that easy, and Linus declined to take it. I think we
> should add a new ->mmap_validate() file operation and save the
> tree-wide cleanup until later.

Note that we already have a mmap_capabilities callout for nommu,
I wonder if we could generalize that.