[tip:x86/cache] x86/intel_rdt: Introduce test to determine if closid is in use

[tip-bot for Reinette Chatre]

Commit-ID:  0b9aa6562650f42da23c29814adc2318c135cef4
Gitweb:     https://git.kernel.org/tip/0b9aa6562650f42da23c29814adc2318c135cef4
Author:     Reinette Chatre <reinette.chatre@xxxxxxxxx>
AuthorDate: Fri, 22 Jun 2018 15:41:57 -0700
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 23 Jun 2018 13:03:41 +0200

x86/intel_rdt: Introduce test to determine if closid is in use

During CAT feature discovery the capacity bitmasks (CBMs) associated
with all the classes of service are initialized to all ones, even if the
class of service is not in use. Introduce a test that can be used to
determine if a class of service is in use. This test enables code
interested in parsing the CBMs to know if its values are meaningful or
can be ignored.

Temporarily mark the function as unused to silence compile warnings
until it is used.

Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: fenghua.yu@xxxxxxxxx
Cc: tony.luck@xxxxxxxxx
Cc: vikas.shivappa@xxxxxxxxxxxxxxx
Cc: gavin.hindman@xxxxxxxxx
Cc: jithu.joseph@xxxxxxxxx
Cc: dave.hansen@xxxxxxxxx
Cc: hpa@xxxxxxxxx
Link: https://lkml.kernel.org/r/798f8d89cd9b12df492d48c14bdc8ee3b39b1c6f.1529706536.git.reinette.chatre@xxxxxxxxx

---
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index d00cce3186ad..659b643fcf94 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -126,6 +126,18 @@ static void closid_free(int closid)
 	closid_free_map |= 1 << closid;
 }
 
+/**
+ * closid_allocated - test if provided closid is in use
+ * @closid: closid to be tested
+ *
+ * Return: true if @closid is currently associated with a resource group,
+ * false if @closid is free
+ */
+static bool __attribute__ ((unused)) closid_allocated(unsigned int closid)
+{
+	return (closid_free_map & (1 << closid)) == 0;
+}
+
 /**
  * rdtgroup_mode_by_closid - Return mode of resource group with closid
  * @closid: closid if the resource group