[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <aOTx-Oj_VN6fVV_s@google.com>
Date: Tue, 7 Oct 2025 10:56:56 +0000
From: Alice Ryhl <aliceryhl@...gle.com>
To: "Onur Özkan" <work@...rozkan.dev>
Cc: rust-for-linux@...r.kernel.org, ojeda@...nel.org, alex.gaynor@...il.com,
boqun.feng@...il.com, gary@...yguo.net, bjorn3_gh@...tonmail.com,
lossin@...nel.org, tmgross@...ch.edu, dakr@...nel.org,
linux-kernel@...r.kernel.org, acourbot@...dia.com, airlied@...il.com,
simona@...ll.ch, maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
tzimmermann@...e.de, corbet@....net, lyude@...hat.com,
linux-doc@...r.kernel.org
Subject: Re: [PATCH 2/3] rust: xarray: abstract `xa_alloc_cyclic`
On Mon, Oct 06, 2025 at 07:30:23PM +0300, Onur Özkan wrote:
> Implements `alloc_cyclic` function to `XArray<T>` that
> wraps `xa_alloc_cyclic` safely.
>
> Resolves a task from the nova/core task list under the "XArray
> bindings [XARR]" section in "Documentation/gpu/nova/core/todo.rst"
> file.
>
> Signed-off-by: Onur Özkan <work@...rozkan.dev>
> ---
> rust/kernel/xarray.rs | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
> index 1b882cd2f58b..4c2fdf53c7af 100644
> --- a/rust/kernel/xarray.rs
> +++ b/rust/kernel/xarray.rs
> @@ -305,6 +305,49 @@ pub fn alloc(
>
> Ok(id)
> }
> +
> + /// Allocates an empty slot within the given `limit`, storing `value` and cycling from `*next`.
> + ///
> + /// May drop the lock if needed to allocate memory, and then reacquire it afterwards.
> + ///
> + /// On success, returns the allocated id.
> + ///
> + /// On failure, returns the element which was attempted to be stored.
> + pub fn alloc_cyclic(
> + &mut self,
> + limit: bindings::xa_limit,
Could we use a Range<u32> type or similar here? I don't think we want a
bindings type.
> + next: &mut u32,
So this is a mutable reference because it writes `*id + 1` to next,
taking wrap-around into account? The docs should probably explain that.
> + value: T,
> + gfp: alloc::Flags,
> + ) -> Result<u32, StoreError<T>> {
> + build_assert!(
> + T::FOREIGN_ALIGN >= 4,
> + "pointers stored in XArray must be 4-byte aligned"
> + );
It should be enough to have this in the constructor. I don't think it's
needed here.
Alice
Powered by blists - more mailing lists