Re: [PATCH v1 06/11] mm: support GUP-triggered unsharing via FAULT_FLAG_UNSHARE (!hugetlb)

[Linus Torvalds]

On Fri, Dec 17, 2021 at 12:42 PM David Hildenbrand <david@xxxxxxxxxx> wrote:
>
> > Then somebody else modified that page, and you got exactly what you
> > asked for - a COW event. The original R/O pin has the original page
> > that it asked for, and can read it just fine.
>
> Where in the code did I ask for a COW event? I asked for a R/O pin, not
> any kind of memory protection.

Why didn't you ask for a shared pin, if that is what you want?

We already support that.

If you don't like the read-only pins, don't use them. It's that simple.

              Linus