[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20251007080402.1a6d19ea@nimda.home>
Date: Tue, 7 Oct 2025 08:04:02 +0300
From: Onur Özkan <work@...rozkan.dev>
To: Boqun Feng <boqun.feng@...il.com>
Cc: rust-for-linux@...r.kernel.org, ojeda@...nel.org, alex.gaynor@...il.com,
gary@...yguo.net, bjorn3_gh@...tonmail.com, lossin@...nel.org,
aliceryhl@...gle.com, 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 1/3] rust: xarray: abstract `xa_alloc`
On Mon, 6 Oct 2025 16:09:42 -0700
Boqun Feng <boqun.feng@...il.com> wrote:
> HI Onur,
>
> On Mon, Oct 06, 2025 at 07:30:22PM +0300, Onur Özkan wrote:
> > Implements `alloc` function to `XArray<T>` that wraps
> > `xa_alloc` safely.
> >
> > Resolves a task from the nova/core task list under the "XArray
> > bindings [XARR]" section in "Documentation/gpu/nova/core/todo.rst"
> > file.
> >
>
> Having this information is good, however I feel it's better if you
> explain/expand what exact the usage will be on the XArray, otherwise,
> it'll be hard for people to dig in the history and find out why we add
> this. Thanks!
>
Very true, thanks.
-Onur
> Regards,
> Boqun
>
> > Signed-off-by: Onur Özkan <work@...rozkan.dev>
> > ---
> > rust/kernel/xarray.rs | 39 +++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 39 insertions(+)
> >
> > diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
> > index a49d6db28845..1b882cd2f58b 100644
> > --- a/rust/kernel/xarray.rs
> > +++ b/rust/kernel/xarray.rs
> > @@ -266,6 +266,45 @@ pub fn store(
> > Ok(unsafe { T::try_from_foreign(old) })
> > }
> > }
> > +
> > + /// Allocates an empty slot within the given limit range and
> > stores `value` there.
> > + ///
> > + /// 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(
> > + &mut self,
> > + limit: bindings::xa_limit,
> > + value: T,
> > + gfp: alloc::Flags,
> > + ) -> Result<u32, StoreError<T>> {
> > + build_assert!(
> > + T::FOREIGN_ALIGN >= 4,
> > + "pointers stored in XArray must be 4-byte aligned"
> > + );
> > +
> > + let new = value.into_foreign();
> > + let mut id: u32 = 0;
> > +
> > + // SAFETY:
> > + // - `self.xa.xa` is valid by the type invariant.
> > + // - `new` came from `T::into_foreign`.
> > + let ret =
> > + unsafe { bindings::__xa_alloc(self.xa.xa.get(), &mut
> > id, new, limit, gfp.as_raw()) }; +
> > + if ret < 0 {
> > + // SAFETY: `__xa_alloc` doesn't take ownership on
> > error.
> > + let value = unsafe { T::from_foreign(new) };
> > + return Err(StoreError {
> > + value,
> > + error: Error::from_errno(ret),
> > + });
> > + }
> > +
> > + Ok(id)
> > + }
> > }
> >
> > // SAFETY: `XArray<T>` has no shared mutable state so it is `Send`
> > iff `T` is `Send`. --
> > 2.51.0
> >
Powered by blists - more mailing lists