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@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/798f8d89cd9b12df492d48c14bdc8ee3b39b1c6f.1529706536.git.reinette.chatre@intel.com

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index d00cce3186ad0d095982b62ce41d413e6219398e..659b643fcf94fafeaa874c3c7d8001252449276e 100644 (file)
--- 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