Each resctrl resource has a list of domain structures. These all begin
with a common rdt_domain_hdr.

Improve type checking of these headers by adding the resource id. Add
domain_header_is_valid() before each call to container_of() to ensure
the domain is the expected type.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 include/linux/resctrl.h            |  9 +++++++++
 arch/x86/kernel/cpu/resctrl/core.c | 10 ++++++----
 fs/resctrl/ctrlmondata.c           |  2 +-
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index a7d92718b653..dfc91c5e8483 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -131,15 +131,24 @@ enum resctrl_domain_type {
  * @list:		all instances of this resource
  * @id:			unique id for this instance
  * @type:		type of this instance
+ * @rid:		resource id for this instance
  * @cpu_mask:		which CPUs share this resource
  */
 struct rdt_domain_hdr {
 	struct list_head		list;
 	int				id;
 	enum resctrl_domain_type	type;
+	enum resctrl_res_level		rid;
 	struct cpumask			cpu_mask;
 };
 
+static inline bool domain_header_is_valid(struct rdt_domain_hdr *hdr,
+					  enum resctrl_domain_type type,
+					  enum resctrl_res_level rid)
+{
+	return !WARN_ON_ONCE(hdr->type != type || hdr->rid != rid);
+}
+
 /**
  * struct rdt_ctrl_domain - group of CPUs sharing a resctrl control resource
  * @hdr:		common header for different domain types
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 06ca5a30140c..8be2619db2e7 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -459,7 +459,7 @@ static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
 
 	hdr = resctrl_find_domain(&r->ctrl_domains, id, &add_pos);
 	if (hdr) {
-		if (WARN_ON_ONCE(hdr->type != RESCTRL_CTRL_DOMAIN))
+		if (!domain_header_is_valid(hdr, RESCTRL_CTRL_DOMAIN, r->rid))
 			return;
 		d = container_of(hdr, struct rdt_ctrl_domain, hdr);
 
@@ -476,6 +476,7 @@ static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
 	d = &hw_dom->d_resctrl;
 	d->hdr.id = id;
 	d->hdr.type = RESCTRL_CTRL_DOMAIN;
+	d->hdr.rid = r->rid;
 	cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
 
 	rdt_domain_reconfigure_cdp(r);
@@ -515,7 +516,7 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
 
 	hdr = resctrl_find_domain(&r->mon_domains, id, &add_pos);
 	if (hdr) {
-		if (WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN))
+		if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
 			return;
 		d = container_of(hdr, struct rdt_mon_domain, hdr);
 
@@ -533,6 +534,7 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
 	d = &hw_dom->d_resctrl;
 	d->hdr.id = id;
 	d->hdr.type = RESCTRL_MON_DOMAIN;
+	d->hdr.rid = r->rid;
 	ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE);
 	if (!ci) {
 		pr_warn_once("Can't find L3 cache for CPU:%d resource %s\n", cpu, r->name);
@@ -593,7 +595,7 @@ static void domain_remove_cpu_ctrl(int cpu, struct rdt_resource *r)
 		return;
 	}
 
-	if (WARN_ON_ONCE(hdr->type != RESCTRL_CTRL_DOMAIN))
+	if (!domain_header_is_valid(hdr, RESCTRL_CTRL_DOMAIN, r->rid))
 		return;
 
 	d = container_of(hdr, struct rdt_ctrl_domain, hdr);
@@ -639,7 +641,7 @@ static void domain_remove_cpu_mon(int cpu, struct rdt_resource *r)
 		return;
 	}
 
-	if (WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN))
+	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
 		return;
 
 	d = container_of(hdr, struct rdt_mon_domain, hdr);
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 0d0ef54fc4de..f248eaf50d3c 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -649,7 +649,7 @@ 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 || WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN)) {
+		if (!hdr || !domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, resid)) {
 			ret = -ENOENT;
 			goto out;
 		}
-- 
2.51.0