fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp()

Clearing a monitor group's mon_data directory is complicated because of the
support for Sub-NUMA Cluster (SNC) mode.

Refactor the SNC case into a helper function to make it easier to add support
for a new telemetry resource.

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

Author: aegl

fs/resctrl/rdtgroup.c

@@ -3229,28 +3229,24 @@ static void mon_rmdir_one_subdir(struct kernfs_node *pkn, char *name, char *subn
 }
 
 /*
- * Remove all subdirectories of mon_data of ctrl_mon groups
- * and monitor groups for the given domain.
- * Remove files and directories containing "sum" of domain data
- * when last domain being summed is removed.
+ * Remove files and directories for one SNC node. If it is the last node
+ * sharing an L3 cache, then remove the upper level directory containing
+ * the "sum" files too.
  */
-static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
-					   struct rdt_domain_hdr *hdr)
+static void rmdir_mondata_subdir_allrdtgrp_snc(struct rdt_resource *r,
+					       struct rdt_domain_hdr *hdr)
 {
 	struct rdtgroup *prgrp, *crgrp;
 	struct rdt_l3_mon_domain *d;
 	char subname[32];
-	bool snc_mode;
 	char name[32];
 
 	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
 		return;
 
 	d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
-	snc_mode = r->mon_scope == RESCTRL_L3_NODE;
-	sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci_id : hdr->id);
-	if (snc_mode)
-		sprintf(subname, "mon_sub_%s_%02d", r->name, hdr->id);
+	sprintf(name, "mon_%s_%02d", r->name, d->ci_id);
+	sprintf(subname, "mon_sub_%s_%02d", r->name, hdr->id);
 
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
 		mon_rmdir_one_subdir(prgrp->mon.mon_data_kn, name, subname);
@@ -3260,6 +3256,30 @@ static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 	}
 }
 
+/*
+ * Remove all subdirectories of mon_data of ctrl_mon groups
+ * and monitor groups for the given domain.
+ */
+static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
+					   struct rdt_domain_hdr *hdr)
+{
+	struct rdtgroup *prgrp, *crgrp;
+	char name[32];
+
+	if (r->rid == RDT_RESOURCE_L3 && r->mon_scope == RESCTRL_L3_NODE) {
+		rmdir_mondata_subdir_allrdtgrp_snc(r, hdr);
+		return;
+	}
+
+	sprintf(name, "mon_%s_%02d", r->name, hdr->id);
+	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+		kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
+
+		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
+			kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
+	}
+}
+
 /*
  * Create a directory for a domain and populate it with monitor files. Create
  * summing monitors when @hdr is NULL. No need to initialize summing monitors.