Re: [PATCH v7 2/2] rust: xarray: Add an abstraction for XArray

[Andreas Hindborg <nmi@metaspace.dk>]

Andreas Hindborg <nmi@metaspace.dk> writes:

> Maíra Canal <mcanal@igalia.com> writes:
>
>> From: Asahi Lina <lina@asahilina.net>
>>
>> The XArray is an abstract data type which behaves like a very large
>> array of pointers. Add a Rust abstraction for this data type.
>>
>> The initial implementation uses explicit locking on get operations and
>> returns a guard which blocks mutation, ensuring that the referenced
>> object remains alive. To avoid excessive serialization, users are
>> expected to use an inner type that can be efficiently cloned (such as
>> Arc<T>), and eagerly clone and drop the guard to unblock other users
>> after a lookup.
>>
>> Future variants may support using RCU instead to avoid mutex locking.
>>
>> This abstraction also introduces a reservation mechanism, which can be
>> used by alloc-capable XArrays to reserve a free slot without immediately
>> filling it, and then do so at a later time. If the reservation is
>> dropped without being filled, the slot is freed again for other users,
>> which eliminates the need for explicit cleanup code.
>>
>> Signed-off-by: Asahi Lina <lina@asahilina.net>
>> Co-developed-by: Maíra Canal <mcanal@igalia.com>
>> Signed-off-by: Maíra Canal <mcanal@igalia.com>
>> ---
>
>
> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>

Actually clippy complains about use of the name `foo` for a variable in
the example. Fix:

diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
index 849915ea633c..aba09cf28c4b 100644
--- a/rust/kernel/xarray.rs
+++ b/rust/kernel/xarray.rs
@@ -185,8 +185,8 @@ fn drop(&mut self) {
 /// let arr = Box::pin_init(XArray::<Arc<Foo>>::new(flags::ALLOC1))
 ///                        .expect("Unable to allocate XArray");
 ///
-/// let foo = Arc::try_new(Foo { a : 1, b: 2 }).expect("Unable to allocate Foo");
-/// let index = arr.alloc(foo).expect("Error allocating Index");
+/// let item = Arc::try_new(Foo { a : 1, b: 2 }).expect("Unable to allocate Foo");
+/// let index = arr.alloc(item).expect("Error allocating Index");
 ///
 /// if let Some(guard) = arr.get_locked(index) {
 ///     assert_eq!(guard.borrow().a, 1);
@@ -195,8 +195,8 @@ fn drop(&mut self) {
 ///     pr_info!("No value found in index {}", index);
 /// }
 ///
-/// let foo = Arc::try_new(Foo { a : 3, b: 4 }).expect("Unable to allocate Foo");
-/// let index = arr.alloc(foo).expect("Error allocating Index");
+/// let item = Arc::try_new(Foo { a : 3, b: 4 }).expect("Unable to allocate Foo");
+/// let index = arr.alloc(item).expect("Error allocating Index");
 ///
 /// if let Some(removed_data) = arr.remove(index) {
 ///     assert_eq!(removed_data.a, 3);


BR Andreas