Re: [PATCH v3 2/2] rust: page: Extend support to existing struct page mappings

[Abdiel Janulgue]

On 21/11/2024 22:17, Jann Horn wrote:
> Does Rust also prevent safe code from invoking inc_ref() on the
> returned Page reference? Normally, the AlwaysRefCounted trait means
> that safe code can create an owned reference from a shared reference,
> right?

While it is possible for someone to *manually* convert the Page 
reference returned in page_slice_to_page() to a refcounted Page (one 
could wrap it in an ARef). However, by design, page_slice_to_page() 
explicitly returns just an ordinary Page reference. We could add an 
invariant in page_slice_to_page() to warn against such usage just in case.

Anyway seems like the consensus from the other thread is to avoid 
refcounting the rust Page abstraction. If we go with that, then that 
moots this issue.

Regards,
Abdiel