x86,fs/resctrl: Refactor domain create/remove using struct rdt_domain_hdr

Up until now, all monitoring events were associated with the L3 resource and it
made sense to use the L3 specific "struct rdt_mon_domain *" argument to functions
operating on domains.

Telemetry events will be tied to a new resource with its instances represented
by a new domain structure that, just like struct rdt_mon_domain, starts with
the generic struct rdt_domain_hdr.

Prepare to support domains belonging to different resources by changing the
calling convention of functions operating on domains.  Pass the generic header
and use that to find the domain specific structure where needed.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com

1 files changed, 10 insertions, 4 deletions

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 905c310de573..3154cdc98a31 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -551,14 +551,21 @@ struct rdt_domain_hdr *resctrl_find_domain(struct list_head *h, int id,
 }
 
 void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
-		    struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
+		    struct rdt_domain_hdr *hdr, struct rdtgroup *rdtgrp,
 		    cpumask_t *cpumask, int evtid, int first)
 {
+	struct rdt_mon_domain *d = NULL;
 	int cpu;
 
 	/* When picking a CPU from cpu_mask, ensure it can't race with cpuhp */
 	lockdep_assert_cpus_held();
 
+	if (hdr) {
+		if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
+			return;
+		d = container_of(hdr, struct rdt_mon_domain, hdr);
+	}
+
 	/*
 	 * Setup the parameters to pass to mon_event_count() to read the data.
 	 */
@@ -653,12 +660,11 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 		 * the resource to find the domain with "domid".
 		 */
 		hdr = resctrl_find_domain(&r->mon_domains, domid, NULL);
-		if (!hdr || !domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, resid)) {
+		if (!hdr) {
 			ret = -ENOENT;
 			goto out;
 		}
-		d = container_of(hdr, struct rdt_mon_domain, hdr);
-		mon_event_read(&rr, r, d, rdtgrp, &d->hdr.cpu_mask, evtid, false);
+		mon_event_read(&rr, r, hdr, rdtgrp, &hdr->cpu_mask, evtid, false);
 	}
 
 checkresult: