[PATCH 05/11] fs/resctrl: Use accurate type for rdt_resource::rid

Reinette Chatre
2026-03-02T18:46:30Z

Every resctrl resource has a unique ID described by enum resctrl_res_level.
enum resctrl_res_level is used in all resource ID initializations and all
resource ID comparisons. All functions consuming the resource ID expects an
enum resctrl_res_level. Of the four structures that contain a resource ID
(struct mon_data, struct mon_evt, struct rdt_domain_hdr, and struct
rdt_resource) only struct rdt_resource does not use enum resctrl_res_level.

Switch the type of rdt_resource::rid to be enum resctrl_res_level to make
it obvious what values are valid, match the type everywhere this member is
used, and obtain benefits from tools that can flag any enum misuse.

Move define of RDT_NUM_RESOURCES outside the enum to enable tools to catch
when a switch() on the resource ID does not handle all the resources and
thus help flag which switch statements need an update when a new resource
is added.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
include/linux/resctrl.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 006e57fd7ca5..48e95f273fb3 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -54,11 +54,11 @@ enum resctrl_res_level {
RDT_RESOURCE_MBA,
RDT_RESOURCE_SMBA,
RDT_RESOURCE_PERF_PKG,
-
- /* Must be the last */
- RDT_NUM_RESOURCES,
+ /* Additions to enum need to update RDT_NUM_RESOURCES. */
};

+#define RDT_NUM_RESOURCES (RDT_RESOURCE_PERF_PKG + 1)
+
/**
* enum resctrl_conf_type - The type of configuration.
* @CDP_NONE: No prioritisation, both code and data are controlled or monitored.
@@ -319,7 +319,7 @@ struct resctrl_mon {
* @cdp_capable: Is the CDP feature available on this resource
*/
struct rdt_resource {
- int rid;
+ enum resctrl_res_level rid;
bool alloc_capable;
bool mon_capable;
enum resctrl_scope ctrl_scope;
--
2.50.1