Resctrl code open codes a search for information about a given cache
level in a couple of places (and more are on the way).

Provide a new inline function get_cpu_cacheinfo_level() in
<linux/cacheinfo.h> to do the search and return a pointer to
the cacheinfo structure.

Simplify the existing get_cpu_cacheinfo_id() by using this new
function to do the search.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 include/linux/cacheinfo.h | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 2cb15fe4fe12..301b0b24f446 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -113,10 +113,10 @@ int acpi_get_cache_info(unsigned int cpu,
 const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
 
 /*
- * Get the id of the cache associated with @cpu at level @level.
+ * Get the cacheinfo structure for cache associated with @cpu at level @level.
  * cpuhp lock must be held.
  */
-static inline int get_cpu_cacheinfo_id(int cpu, int level)
+static inline struct cacheinfo *get_cpu_cacheinfo_level(int cpu, int level)
 {
 	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
 	int i;
@@ -124,12 +124,23 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level)
 	for (i = 0; i < ci->num_leaves; i++) {
 		if (ci->info_list[i].level == level) {
 			if (ci->info_list[i].attributes & CACHE_ID)
-				return ci->info_list[i].id;
-			return -1;
+				return &ci->info_list[i];
+			return NULL;
 		}
 	}
 
-	return -1;
+	return NULL;
+}
+
+/*
+ * Get the id of the cache associated with @cpu at level @level.
+ * cpuhp lock must be held.
+ */
+static inline int get_cpu_cacheinfo_id(int cpu, int level)
+{
+	struct cacheinfo *ci = get_cpu_cacheinfo_level(cpu, level);
+
+	return ci ? ci->id : -1;
 }
 
 #ifdef CONFIG_ARM64
-- 
2.45.0

Hi Tony,

On 5/31/24 12:57 PM, Tony Luck wrote:
> Resctrl code open codes a search for information about a given cache
> level in a couple of places (and more are on the way).
> 
> Provide a new inline function get_cpu_cacheinfo_level() in
> <linux/cacheinfo.h> to do the search and return a pointer to
> the cacheinfo structure.
> 
> Simplify the existing get_cpu_cacheinfo_id() by using this new
> function to do the search.
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
>   include/linux/cacheinfo.h | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
> index 2cb15fe4fe12..301b0b24f446 100644
> --- a/include/linux/cacheinfo.h
> +++ b/include/linux/cacheinfo.h
> @@ -113,10 +113,10 @@ int acpi_get_cache_info(unsigned int cpu,
>   const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
>   
>   /*
> - * Get the id of the cache associated with @cpu at level @level.
> + * Get the cacheinfo structure for cache associated with @cpu at level @level.

"for cache" -> "for the cache"?

>    * cpuhp lock must be held.
>    */
> -static inline int get_cpu_cacheinfo_id(int cpu, int level)
> +static inline struct cacheinfo *get_cpu_cacheinfo_level(int cpu, int level)
>   {
>   	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
>   	int i;
> @@ -124,12 +124,23 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level)
>   	for (i = 0; i < ci->num_leaves; i++) {
>   		if (ci->info_list[i].level == level) {
>   			if (ci->info_list[i].attributes & CACHE_ID)
> -				return ci->info_list[i].id;
> -			return -1;
> +				return &ci->info_list[i];
> +			return NULL;
>   		}
>   	}
>   
> -	return -1;
> +	return NULL;
> +}
> +
> +/*
> + * Get the id of the cache associated with @cpu at level @level.
> + * cpuhp lock must be held.
> + */
> +static inline int get_cpu_cacheinfo_id(int cpu, int level)
> +{
> +	struct cacheinfo *ci = get_cpu_cacheinfo_level(cpu, level);
> +
> +	return ci ? ci->id : -1;
>   }
>   
>   #ifdef CONFIG_ARM64

Just the one nitpick from me.
Thank you.

| Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette