Re: [PATCH v9 8/8] task: rust: rework how current is accessed

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Fri, Nov 22, 2024 at 04:53:58PM +0100, Alice Ryhl wrote:
> On Fri, Nov 22, 2024 at 4:41 PM Alice Ryhl <aliceryhl@google.com> wrote:
> >
> > Introduce a new type called `CurrentTask` that lets you perform various
> > operations that are only safe on the `current` task. Use the new type to
> > provide a way to access the current mm without incrementing its
> > refcount.
> >
> > With this change, you can write stuff such as
> >
> >         let vma = current!().mm().lock_vma_under_rcu(addr);
> >
> > without incrementing any refcounts.
> >
> > Signed-off-by: Alice Ryhl <aliceryhl@google.com>
>
> Oh, that's awkward, I was testing this change using a config file that
> was missing CONFIG_RUST=y, so it didn't compile the code at all. You
> need the following imports for this to work:
>
> diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
> index 103d235eb844..60659076997a 100644
> --- a/rust/kernel/task.rs
> +++ b/rust/kernel/task.rs
> @@ -7,7 +7,8 @@
>  use crate::{
>      bindings,
>      ffi::{c_int, c_long, c_uint},
> -    types::{NotThreadSafe, Opaque},
> +    mm::MmWithUser,
> +    types::Opaque,
>  };
>  use core::{
>      cmp::{Eq, PartialEq},
>
> Otherwise the code should be correct. You can fetch the tree with this fixed at:
> https://github.com/Darksonn/linux/commits/b4/vma/
>
> I'll fix it in the next version, but I will wait for review before I send that.

Sure, no problem, we can just make this a predicate for the ack.

>
> Alice