selftests/resctrl: Add helper to convert L2/3 to integer

"L2"/"L3" conversion to integer is embedded into get_cache_size()
which prevents reuse.

Create a helper for the cache string to integer conversion to make
it reusable.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/resctrl/resctrlfs.c

@@ -94,6 +94,23 @@ int umount_resctrlfs(void)
 	return 0;
 }
 
+/*
+ * get_cache_level - Convert cache level from string to integer
+ * @cache_type:		Cache level as string
+ *
+ * Return: cache level as integer or -1 if @cache_type is invalid.
+ */
+static int get_cache_level(const char *cache_type)
+{
+	if (!strcmp(cache_type, "L3"))
+		return 3;
+	if (!strcmp(cache_type, "L2"))
+		return 2;
+
+	ksft_print_msg("Invalid cache level\n");
+	return -1;
+}
+
 /*
  * get_resource_id - Get socket number/l3 id for a specified CPU
  * @cpu_no:	CPU number
@@ -144,14 +161,9 @@ int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size
 	int length, i, cache_num;
 	FILE *fp;
 
-	if (!strcmp(cache_type, "L3")) {
-		cache_num = 3;
-	} else if (!strcmp(cache_type, "L2")) {
-		cache_num = 2;
-	} else {
-		ksft_print_msg("Invalid cache level\n");
-		return -1;
-	}
+	cache_num = get_cache_level(cache_type);
+	if (cache_num < 0)
+		return cache_num;
 
 	sprintf(cache_path, "/sys/bus/cpu/devices/cpu%d/cache/index%d/size",
 		cpu_no, cache_num);