Re: [PATCH v3] rust: mm: add abstractions for mm_struct and vm_area_struct

[Alice Ryhl <aliceryhl@google.com>]

On Thu, Aug 1, 2024 at 4:02 PM Benno Lossin <benno.lossin@proton.me> wrote:
>
> On 01.08.24 14:58, Alice Ryhl wrote:
> > diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs
> > new file mode 100644
> > index 000000000000..ed2db893fb79
> > --- /dev/null
> > +++ b/rust/kernel/mm.rs
> > @@ -0,0 +1,337 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +// Copyright (C) 2024 Google LLC.
> > +
> > +//! Memory management.
> > +//!
> > +//! C header: [`include/linux/mm.h`](../../../../include/linux/mm.h)
> > +
> > +use crate::{
> > +    bindings,
> > +    types::{ARef, AlwaysRefCounted, Opaque},
> > +};
> > +
> > +use core::{
> > +    ops::Deref,
> > +    ptr::{self, NonNull},
> > +};
> > +
> > +pub mod virt;
> > +
> > +/// A wrapper for the kernel's `struct mm_struct`.
> > +///
> > +/// Since `mm_users` may be zero, the associated address space may not exist anymore. You must use
>
> Can it also be the case that the space never existed to begin with? Then
> I would write "the associated address space may not exist."
>
> Also I think it makes more sense to use "You can use [`mmget_not_zero`]
> to be able to access the address space." instead of the second sentence.

I took the "may not exist anymore" wording from the C side, so I'm
going to keep it.

Alice