[PATCH v11 20/31] fs/resctrl: Refactor Sub-NUMA Cluster (SNC) in mkdir/rmdir code flow

[Tony Luck <tony.luck@intel.com>]

SNC is only present in the RDT_RESOURCE_L3 domain.

Refactor code that makes and removes directories under "mon_data" to
special case the L3 resource.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 fs/resctrl/rdtgroup.c | 50 +++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 6e8937f94e7a..cab5cb9e6c93 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -3155,6 +3155,7 @@ static void mon_rmdir_one_subdir(struct kernfs_node *pkn, char *name, char *subn
 		return;
 	kernfs_put(kn);
 
+	/* Subdirectories are only present on SNC enabled systems */
 	if (kn->dir.subdirs <= 1)
 		kernfs_remove(kn);
 	else
@@ -3171,19 +3172,24 @@ static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 					   struct rdt_domain_hdr *hdr)
 {
 	struct rdtgroup *prgrp, *crgrp;
-	struct rdt_l3_mon_domain *d;
+	int domid = hdr->id;
 	char subname[32];
-	bool snc_mode;
 	char name[32];
 
-	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
-		return;
+	if (r->rid == RDT_RESOURCE_L3) {
+		struct rdt_l3_mon_domain *d;
 
-	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 : d->hdr.id);
-	if (snc_mode)
-		sprintf(subname, "mon_sub_%s_%02d", r->name, d->hdr.id);
+		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? */
+		if (r->mon_scope == RESCTRL_L3_NODE) {
+			domid = d->ci_id;
+			sprintf(subname, "mon_sub_%s_%02d", r->name, hdr->id);
+		}
+	}
+	sprintf(name, "mon_%s_%02d", r->name, domid);
 
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
 		mon_rmdir_one_subdir(prgrp->mon.mon_data_kn, name, subname);
@@ -3213,7 +3219,7 @@ static int mon_add_all_files(struct kernfs_node *kn, struct rdt_domain_hdr *hdr,
 		if (ret)
 			return ret;
 
-		if (!do_sum && resctrl_is_mbm_event(mevt->evtid))
+		if (r->rid == RDT_RESOURCE_L3 && !do_sum && resctrl_is_mbm_event(mevt->evtid))
 			mon_event_read(&rr, r, hdr, prgrp, &hdr->cpu_mask, mevt, true);
 	}
 
@@ -3225,19 +3231,27 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
 				struct rdt_resource *r, struct rdtgroup *prgrp)
 {
 	struct kernfs_node *kn, *ckn;
-	struct rdt_l3_mon_domain *d;
+	bool snc_mode = false;
+	int domid = hdr->id;
 	char name[32];
-	bool snc_mode;
 	int ret = 0;
 
 	lockdep_assert_held(&rdtgroup_mutex);
 
-	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
-		return -EINVAL;
+	if (r->rid == RDT_RESOURCE_L3) {
+		snc_mode = r->mon_scope == RESCTRL_L3_NODE;
+		if (snc_mode) {
+			struct rdt_l3_mon_domain *d;
+
+			if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
+				return -EINVAL;
+
+			d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
+			domid = d->ci_id;
+		}
+	}
+	sprintf(name, "mon_%s_%02d", r->name, domid);
 
-	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 : d->hdr.id);
 	kn = kernfs_find_and_get(parent_kn, name);
 	if (kn) {
 		/*
@@ -3253,7 +3267,7 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
 		ret = rdtgroup_kn_set_ugid(kn);
 		if (ret)
 			goto out_destroy;
-		ret = mon_add_all_files(kn, hdr, r, prgrp, hdr->id, snc_mode);
+		ret = mon_add_all_files(kn, hdr, r, prgrp, domid, snc_mode);
 		if (ret)
 			goto out_destroy;
 	}
-- 
2.51.0