Re: [PATCH v3 5/9] gpu: nova-core: gsp: cmdq: split RPC parsing part of the receive path

[Eliot Courtney]

On Wed Sep 30, 2026 at 11:55 PM JST, Alexandre Courbot wrote:
> The RPC parsing should not be done in the same method as the transport
> header parsing. Split it out and introduce a `RpcMessage` type to
> indicate messages that have been successfully parsed as RPC. This makes
> the code easier to move around into its new destination.
>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> ---
>  drivers/gpu/nova-core/gsp/cmdq.rs | 37 +++++++++++++++++++++++++++++++++----
>  1 file changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
> index d8a7716fc500..b8a9e02b76fe 100644
> --- a/drivers/gpu/nova-core/gsp/cmdq.rs
> +++ b/drivers/gpu/nova-core/gsp/cmdq.rs
> @@ -553,6 +553,17 @@ struct GspMessage<'a> {
>      contents: (&'a [u8], &'a [u8]),
>  }
>  
> +/// A RPC message ready to be processed from the message queue.
> +///
> +/// This is the type returned by [`CmdqInner::parse_rpc_message`].
> +struct RpcMessage<'a> {
> +    // Reference to the RPC header of the message.
> +    header: &'a RpcMessageHeader,
> +    // Slices to the contents of the message. The second slice is zero unless the message loops
> +    // over the message queue.
> +    contents: (&'a [u8], &'a [u8]),
> +}
> +
>  /// GSP command queue.
>  ///
>  /// Provides the ability to send commands and receive messages from the GSP using a shared memory
> @@ -794,7 +805,7 @@ fn send_command<M>(&mut self, command: M) -> Result
>      ///   message queue.
>      ///
>      /// Error codes returned by the message constructor are propagated as-is.
> -    fn wait_for_msg(&self, timeout: Delta) -> Result<GspMessage<'_>> {
> +    fn wait_for_msg(&self, timeout: Delta) -> Result<RpcMessage<'_>> {

This gets changed back to `GspMessage` return value in the next patch,
and also introduces a bug [1]. What about just keeping return
`GspMessage` here? You can move RpcMessage to the next patch.

[1]: https://lore.kernel.org/all/DLT4O89RYP29.UKGBMIJD8ZSC@xxxxxxxxxx/