Re: [PATCH 2/8] rust: dma: add generalized container for types other than slices

[Gary Guo]

On Tue Mar 17, 2026 at 6:50 AM GMT, Alice Ryhl wrote:
> On Tue, Mar 03, 2026 at 05:22:53PM +0100, Danilo Krummrich wrote:
>> From: Gary Guo <gary@xxxxxxxxxxx>
>> 
>> Currently, `CoherentAllocation` is concecptually a DMA coherent container
>> of a slice of `[T]` of runtime-checked length. Generalize it by creating
>> `dma::Coherent<T>` which can hold any value of `T`.
>> `Coherent::alloc_with_attrs` is implemented but not yet exposed, as I
>> believe we should not expose the way to obtain an uninitialized coherent
>> region.
>> 
>> `Coherent<[T]>` provides a `len` method instead of the previous `count()`
>> method to be consistent with methods on slices.
>> 
>> The existing type is re-defined as a type alias of `Coherent<[T]>` to ease
>> transition. Methods in use are not yet removed.
>> 
>> Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
>> Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
>
> I see you have both `size()` and `len()`. I think it would be clearer to
> rename `size()` to `len_bytes()`.

This is an API that already exists and I simply moved it around so it is
implemented for all types, not just `[T]`.

I also think that `size()` quite unambiguously means the size in bytes (like, in
all allocation and I/O APIs, `size` means size of object in bytes); I don't see
much benefit in renaming it `len_bytes`.

Best,
Gary

>
> Otherwise LGTM.
> Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
>
> Alice