Re: [PATCH] rust: page: implement BorrowedPage

["Danilo Krummrich" <dakr@kernel.org>]

On Tue Aug 5, 2025 at 2:53 PM CEST, Danilo Krummrich wrote:
> On Tue Aug 5, 2025 at 2:30 PM CEST, Daniel Almeida wrote:
>>> +/// Representation of a non-owning reference to a [`Page`].
>>> +///
>>> +/// This type provides a borrowed version of a [`Page`] that is owned by some other entity, e.g. a
>>> +/// [`Vmalloc`] allocation such as [`VBox`].
>>> +///
>>> +/// # Example
>>> +///
>>> +/// ```
>>> +/// # use kernel::{bindings, prelude::*};
>>> +/// use kernel::page::{BorrowedPage, Page, PAGE_SIZE};
>>> +/// # use core::ptr;
>>> +/// # use core::ptr::NonNull;
>>> +///
>>> +/// trait PageOwner {
>>
>> What is this trait for? Perhaps this assumes some previous discussion that is
>> not in the patch itself?
>
> It's just example code to show how a BorrowedPage may be obtained from something
> that owns a page, i.e. a PageOwner.

Maybe let me simplify the example a bit and just use the following function for
the example instead of the generic trait approach.

	 fn borrow_first_page<'a>(vbox: &'a mut VBox<MaybeUninit<[u8; PAGE_SIZE]>>) -> BorrowedPage<'a>