Re: [PATCH v4 04/13] powerpc/rtas: Factor out function descriptor lookup

[Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>]

Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org>
writes:

> From: Nathan Lynch <nathanl@linux.ibm.com>
>
> Move the function descriptor table lookup out of rtas_function_token()
> into a separate routine for use in new code to follow. No functional
> change.
>

Reviewed-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>

> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
> ---
>  arch/powerpc/kernel/rtas.c | 31 +++++++++++++++++++------------
>  1 file changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index f0051881348a..1fc0b3fffdd1 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -469,29 +469,36 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
>  static DEFINE_RAW_SPINLOCK(rtas_lock);
>  static struct rtas_args rtas_args;
>  
> -/**
> - * rtas_function_token() - RTAS function token lookup.
> - * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
> - *
> - * Context: Any context.
> - * Return: the token value for the function if implemented by this platform,
> - *         otherwise RTAS_UNKNOWN_SERVICE.
> - */
> -s32 rtas_function_token(const rtas_fn_handle_t handle)
> +static struct rtas_function *rtas_function_lookup(const rtas_fn_handle_t handle)
>  {
>  	const size_t index = handle.index;
>  	const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
>  
>  	if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
> -		return RTAS_UNKNOWN_SERVICE;
> +		return NULL;
>  	/*
>  	 * Various drivers attempt token lookups on non-RTAS
>  	 * platforms.
>  	 */
>  	if (!rtas.dev)
> -		return RTAS_UNKNOWN_SERVICE;
> +		return NULL;
> +
> +	return &rtas_function_table[index];
> +}
> +
> +/**
> + * rtas_function_token() - RTAS function token lookup.
> + * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
> + *
> + * Context: Any context.
> + * Return: the token value for the function if implemented by this platform,
> + *         otherwise RTAS_UNKNOWN_SERVICE.
> + */
> +s32 rtas_function_token(const rtas_fn_handle_t handle)
> +{
> +	const struct rtas_function *func = rtas_function_lookup(handle);
>  
> -	return rtas_function_table[index].token;
> +	return func ? func->token : RTAS_UNKNOWN_SERVICE;
>  }
>  EXPORT_SYMBOL_GPL(rtas_function_token);
>  
>
> -- 
> 2.41.0