Re: [PATCH v4 7/9] gpu: nova-core: gsp: add command_size helper

["Gary Guo" <gary@garyguo.net>]

On Mon Mar 2, 2026 at 11:42 AM GMT, Eliot Courtney wrote:
> Add a helper function which computes the size of a command.
>
> Tested-by: Zhi Wang <zhiw@nvidia.com>
> Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
> ---
>  drivers/gpu/nova-core/gsp/cmdq.rs | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
> index 9f74f0898d90..4a663a5b3437 100644
> --- a/drivers/gpu/nova-core/gsp/cmdq.rs
> +++ b/drivers/gpu/nova-core/gsp/cmdq.rs
> @@ -450,6 +450,15 @@ struct GspMessage<'a> {
>      contents: (&'a [u8], &'a [u8]),
>  }
>  
> +/// Computes the total size of the command (including its variable-length payload) without the
> +/// [`GspMsgElement`] header.
> +fn command_size<M>(command: &M) -> usize
> +where
> +    M: CommandToGsp,
> +{
> +    size_of::<M::Command>() + command.variable_payload_len()
> +}
> +

This could just a provided method on `CommandToGsp`?

Best,
Gary

>  /// GSP command queue.
>  ///
>  /// Provides the ability to send commands and receive messages from the GSP using a shared memory
> @@ -526,7 +535,7 @@ pub(crate) fn send_command<M>(&mut self, bar: &Bar0, command: M) -> Result
>          // This allows all error types, including `Infallible`, to be used for `M::InitError`.
>          Error: From<M::InitError>,
>      {
> -        let command_size = size_of::<M::Command>() + command.variable_payload_len();
> +        let command_size = command_size(&command);
>          let dst = self
>              .gsp_mem
>              .allocate_command(command_size, Delta::from_secs(1))?;