linux-kernel - [PATCH V2 3/9] x86/intel_rdt: Global closid helper to support future fixes

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Date:   Sat, 15 Sep 2018 14:58:21 -0700
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Thomas Gleixner" <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>, "H Peter Anvin" <hpa@...or.com>,
        "Tony Luck" <tony.luck@...el.com>
Cc:     "Chatre, Reinette" <reinette.chatre@...el.com>,
        "Xiaochen Shen" <xiaochen.shen@...el.com>,
        "Chen Yu" <yu.c.chen@...el.com>,
        "linux-kernel" <linux-kernel@...r.kernel.org>,
        "x86" <x86@...nel.org>, "Fenghua Yu" <fenghua.yu@...el.com>
Subject: [PATCH V2 3/9] x86/intel_rdt: Global closid helper to support future fixes

From: Reinette Chatre <reinette.chatre@...el.com>

The number of CLOSIDs supported by a system is the minimum number of
CLOSIDs supported by any of its resources. Care should be taken when
iterating over the CLOSIDs of a resource since it may be that the number
of CLOSIDs supported on the system is less than the number of CLOSIDs
supported by the resource.

Introduce a helper function that can be used to query the number of
CLOSIDs that is supported by all resources, irrespective of how many
CLOSIDs are supported by a particular resource.

Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
---
 arch/x86/kernel/cpu/intel_rdt.h          | 1 +
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 78266c798280..285eb3ec4200 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -544,6 +544,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp);
 void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp);
 struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r);
 int update_domains(struct rdt_resource *r, int closid);
+int closids_supported(void);
 void closid_free(int closid);
 int alloc_rmid(void);
 void free_rmid(u32 rmid);
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 32e8bbdf2400..b372923eb209 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -97,6 +97,12 @@ void rdt_last_cmd_printf(const char *fmt, ...)
  *   limited as the number of resources grows.
  */
 static int closid_free_map;
+static int closid_free_map_len;
+
+int closids_supported(void)
+{
+	return closid_free_map_len;
+}
 
 static void closid_init(void)
 {
@@ -111,6 +117,7 @@ static void closid_init(void)
 
 	/* CLOSID 0 is always reserved for the default group */
 	closid_free_map &= ~1;
+	closid_free_map_len = rdt_min_closid;
 }
 
 static int closid_alloc(void)
-- 
2.19.0