Re: [PATCH v4 16/20] rust: io: add `read_val` and `write_val` functions on `Io`

[sashiko-bot@kernel.org]

> Provide `read_val` and `write_val` that allow I/O views to be accessed when
> they're narrowed down to just views of primitives.
> 
> This is used to provide `io_read!` and `io_write!` macros, which are
> generalized version of current `dma_read!` and `dma_write!` macro that work
> for all types that implement `Io`.
> 
> Note though `io_read!` and `io_write!` only works if backend implements
> `IoCapable` for the type; which is typically only implemented for
> atomically accessible primitives. `dma_read!` and `dma_write!` currently
> supports them via `read_volatile` and `write_volatile`; this can be
> undesirable for aggregates as LLVM may turn them to multiple instructions
> to access parts and re-assemble, even if they could be combined to a single
> instruction. Thus, `io_read!()` and `io_write!()` does not fully replace
> `dma_read!()` and `dma_write!()` in this scenario. The ability to
> read/write aggregates (when atomicity is of no concern) is better served
> with copying primitives (e.g. memcpy_{from,to}io).
> 
> Signed-off-by: Gary Guo <gary@garyguo.net>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611-io_projection-v4-0-1f7224b02dcb@garyguo.net?part=16