Re: [PATCH v7 17/19] gup: Introduce FOLL_NOFAULT flag to disable page faults

On Thu, Sep 09, 2021 at 10:17:14AM -0700, Linus Torvalds wrote:

So I think we should treat FOLL_FAST_ONLY as a special "internal to
gup.c" flag, and perhaps not really compare it to the new
FOLL_NOFAULT.

In fact, maybe we could even just make FOLL_FAST_ONLY be the high bit,
and not expose it in <linux/mm.h> and make it entirely private as a
name in gup.c.

There are quite a few bits like that.  I've been wanting to make them
private for 5.16.