linux-kernel - [PATCH v15-RFC 4/8] x86/resctrl: Add helper function to look up domain

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Date: Tue, 30 Jan 2024 14:20:30 -0800
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	Jonathan Corbet <corbet@....net>,
	Shuah Khan <skhan@...uxfoundation.org>,
	x86@...nel.org
Cc: Shaopeng Tan <tan.shaopeng@...itsu.com>,
	James Morse <james.morse@....com>,
	Jamie Iles <quic_jiles@...cinc.com>,
	Babu Moger <babu.moger@....com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Drew Fustini <dfustini@...libre.com>,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH v15-RFC 4/8] x86/resctrl: Add helper function to look up domain_id from scope

Prepare for more options for scope of resources. Add some diagnostic
messages if lookup fails.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/kernel/cpu/resctrl/core.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index d89dce63397b..59e6aa7abef5 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -499,6 +499,19 @@ static int arch_domain_mbm_alloc(u32 num_rmid, struct rdt_hw_domain *hw_dom)
 	return 0;
 }
 
+static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
+{
+	switch (scope) {
+	case RESCTRL_L2_CACHE:
+	case RESCTRL_L3_CACHE:
+		return get_cpu_cacheinfo_id(cpu, scope);
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
 /*
  * domain_add_cpu - Add a cpu to a resource's domain list.
  *
@@ -514,12 +527,18 @@ static int arch_domain_mbm_alloc(u32 num_rmid, struct rdt_hw_domain *hw_dom)
  */
 static void domain_add_cpu(int cpu, struct rdt_resource *r)
 {
-	int id = get_cpu_cacheinfo_id(cpu, r->scope);
+	int id = get_domain_id_from_scope(cpu, r->scope);
 	struct list_head *add_pos = NULL;
 	struct rdt_hw_domain *hw_dom;
 	struct rdt_domain *d;
 	int err;
 
+	if (id < 0) {
+		pr_warn_once("Can't find domain id for CPU:%d scope:%d for resource %s\n",
+			     cpu, r->scope, r->name);
+		return;
+	}
+
 	d = rdt_find_domain(r, id, &add_pos);
 	if (IS_ERR(d)) {
 		pr_warn("Couldn't find cache id for CPU %d\n", cpu);
@@ -564,10 +583,16 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
 
 static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 {
-	int id = get_cpu_cacheinfo_id(cpu, r->scope);
+	int id = get_domain_id_from_scope(cpu, r->scope);
 	struct rdt_hw_domain *hw_dom;
 	struct rdt_domain *d;
 
+	if (id < 0) {
+		pr_warn_once("Can't find domain id for CPU:%d scope:%d for resource %s\n",
+			     cpu, r->scope, r->name);
+		return;
+	}
+
 	d = rdt_find_domain(r, id, NULL);
 	if (IS_ERR_OR_NULL(d)) {
 		pr_warn("Couldn't find cache id for CPU %d\n", cpu);
-- 
2.43.0