[PATCH v5 08/15] mm: Add unsafe_follow_pfn

[Christoph Hellwig]

On Mon, Nov 02, 2020 at 11:52:56AM -0400, Jason Gunthorpe wrote:
> Need to hold the lock to check that and there are two ways to register
> notifiers these days, so it feels to expensive to me.
> 
> CH's 'export symbol only for kvm' really does seem the most robust way
> to handle this though.

I hope I can get that done for this merge window, but I'm not sure.

I still think we should at least have a new name for the old follow_pfn
that no one should use.  And it should sound more scary than
unsafe_follow_pfn :)