linux-kernel - [PATCH v8 16/21] x86/resctrl: Always initialise rid field in rdt_resources

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Message-Id: <20250411164229.23413-17-james.morse@arm.com>
Date: Fri, 11 Apr 2025 16:42:24 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org,
	linux-kernel@...r.kernel.org
Cc: Reinette Chatre <reinette.chatre@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	H Peter Anvin <hpa@...or.com>,
	Babu Moger <Babu.Moger@....com>,
	James Morse <james.morse@....com>,
	shameerali.kolothum.thodi@...wei.com,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	carl@...amperecomputing.com,
	lcherian@...vell.com,
	bobo.shaobowang@...wei.com,
	tan.shaopeng@...itsu.com,
	baolin.wang@...ux.alibaba.com,
	Jamie Iles <quic_jiles@...cinc.com>,
	Xin Hao <xhao@...ux.alibaba.com>,
	peternewman@...gle.com,
	dfustini@...libre.com,
	amitsinght@...vell.com,
	David Hildenbrand <david@...hat.com>,
	Rex Nie <rex.nie@...uarmicro.com>,
	Dave Martin <dave.martin@....com>,
	Koba Ko <kobak@...dia.com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	fenghuay@...dia.com
Subject: [PATCH v8 16/21] x86/resctrl: Always initialise rid field in rdt_resources_all[]

x86 has an array, rdt_resources_all[], of all possible resources.
The for-each-resource walkers depend on the rid field of all
resources being initialised.

If the array ever grows due to another architecture adding a resource
type that is not defined on x86, the for-each-resources walkers will
loop forever.

Initialise all the rid values in resctrl_arch_late_init() before
any for-each-resource walker can be called.

Signed-off-by: James Morse <james.morse@....com>

---
Changes since v7:
 * Split out of a previous patch due to a botched merged conflict.
---
 arch/x86/kernel/cpu/resctrl/core.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 58d7c6accdf2..ce684da600bc 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -60,7 +60,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 	[RDT_RESOURCE_L3] =
 	{
 		.r_resctrl = {
-			.rid			= RDT_RESOURCE_L3,
 			.name			= "L3",
 			.ctrl_scope		= RESCTRL_L3_CACHE,
 			.mon_scope		= RESCTRL_L3_CACHE,
@@ -74,7 +73,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 	[RDT_RESOURCE_L2] =
 	{
 		.r_resctrl = {
-			.rid			= RDT_RESOURCE_L2,
 			.name			= "L2",
 			.ctrl_scope		= RESCTRL_L2_CACHE,
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_L2),
@@ -86,7 +84,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 	[RDT_RESOURCE_MBA] =
 	{
 		.r_resctrl = {
-			.rid			= RDT_RESOURCE_MBA,
 			.name			= "MB",
 			.ctrl_scope		= RESCTRL_L3_CACHE,
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_MBA),
@@ -96,7 +93,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 	[RDT_RESOURCE_SMBA] =
 	{
 		.r_resctrl = {
-			.rid			= RDT_RESOURCE_SMBA,
 			.name			= "SMBA",
 			.ctrl_scope		= RESCTRL_L3_CACHE,
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_SMBA),
@@ -996,7 +992,11 @@ void resctrl_cpu_detect(struct cpuinfo_x86 *c)
 static int __init resctrl_arch_late_init(void)
 {
 	struct rdt_resource *r;
-	int state, ret;
+	int state, ret, i;
+
+	/* Initialise all rid values for_each_rdt_resource() */
+	for (i = 0; i < RDT_NUM_RESOURCES; i++)
+		rdt_resources_all[i].r_resctrl.rid = i;
 
 	/*
 	 * Initialize functions(or definitions) that are different
-- 
2.20.1