[PATCH 02/33] ACPI / PPTT: Stop acpi_count_levels() expecting callers to clear levels

[Shaopeng Tan (Fujitsu)]

Hello Ben,

> From: James Morse <james.morse at arm.com>
> 
> In acpi_count_levels(), the initial value of *levels passed by the caller is really
> an implementation detail of acpi_count_levels(), so it is unreasonable to
> expect the callers of this function to know what to pass in for this parameter.
> The only sensible initial value is 0, which is what the only upstream caller
> (acpi_get_cache_info()) passes.
> 
> Use a local variable for the starting cache level in acpi_count_levels(), and pass
> the result back to the caller via the function return value.
> 
> Get rid of the levels parameter, which has no remaining purpose.
> 
> Fix acpi_get_cache_info() to match.
> 
> Suggested-by: Jonathan Cameron <jonathan.cameron at huawei.com>
> Signed-off-by: James Morse <james.morse at arm.com>
> Reviewed-by: Lorenzo Pieralisi <lpieralisi at kernel.org>
> Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>
> Reviewed-by: Fenghua Yu <fenghuay at nvidia.com>
> Tested-by: Fenghua Yu <fenghuay at nvidia.com>
> Tested-by: Shaopeng Tan <tan.shaopeng at jp.fujitsu.com>
> Tested-by: Peter Newman <peternewman at google.com>
> Reviewed-by: Gavin Shan <gshan at redhat.com>
> Signed-off-by: Ben Horgan <ben.horgan at arm.com>
> ---
"Reviewed-by" and "Tested-by" are mixed together.
It would be better to group them.
(Not just in this patch, but in other patches as well.)

Best regards,
Shaopeng TAN


> Changes since v3:
> s/starting_level/current_level/ (Jonathan)
> ---
>  drivers/acpi/pptt.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c index
> 69917cc6bd2f..1027ca3566b1 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -177,14 +177,14 @@ acpi_find_cache_level(struct acpi_table_header
> *table_hdr,  }
> 
>  /**
> - * acpi_count_levels() - Given a PPTT table, and a CPU node, count the cache
> - * levels and split cache levels (data/instruction).
> + * acpi_count_levels() - Given a PPTT table, and a CPU node, count the
> + * total number of levels and split cache levels (data/instruction).
>   * @table_hdr: Pointer to the head of the PPTT table
>   * @cpu_node: processor node we wish to count caches for
> - * @levels: Number of levels if success.
>   * @split_levels:	Number of split cache levels (data/instruction) if
>   *			success. Can by NULL.
>   *
> + * Return: number of levels.
>   * Given a processor node containing a processing unit, walk into it and count
>   * how many levels exist solely for it, and then walk up each level until we hit
>   * the root node (ignore the package level because it may be possible to have
> @@ -192,14 +192,18 @@ acpi_find_cache_level(struct acpi_table_header
> *table_hdr,
>   * split cache levels (data/instruction) that exist at each level on the way
>   * up.
>   */
> -static void acpi_count_levels(struct acpi_table_header *table_hdr,
> -			      struct acpi_pptt_processor *cpu_node,
> -			      unsigned int *levels, unsigned int *split_levels)
> +static int acpi_count_levels(struct acpi_table_header *table_hdr,
> +			     struct acpi_pptt_processor *cpu_node,
> +			     unsigned int *split_levels)
>  {
> +	int current_level = 0;
> +
>  	do {
> -		acpi_find_cache_level(table_hdr, cpu_node, levels,
> split_levels, 0, 0);
> +		acpi_find_cache_level(table_hdr, cpu_node, &current_level,
> +split_levels, 0, 0);
>  		cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
>  	} while (cpu_node);
> +
> +	return current_level;
>  }
> 
>  /**
> @@ -645,7 +649,7 @@ int acpi_get_cache_info(unsigned int cpu, unsigned int
> *levels,
>  	if (!cpu_node)
>  		return -ENOENT;
> 
> -	acpi_count_levels(table, cpu_node, levels, split_levels);
> +	*levels = acpi_count_levels(table, cpu_node, split_levels);
> 
>  	pr_debug("Cache Setup: last_level=%d split_levels=%d\n",
>  		 *levels, split_levels ? *split_levels : -1);
> --
> 2.43.0