x86/apic: Factor out default vector_allocation_domain() operation

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131449.GC4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index bef5717..feb2dbd 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -615,6 +615,27 @@
 default_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
 			       const struct cpumask *andmask);
 
+static inline void
+flat_vector_allocation_domain(int cpu, struct cpumask *retmask)
+{
+	/* Careful. Some cpus do not strictly honor the set of cpus
+	 * specified in the interrupt destination when using lowest
+	 * priority interrupt delivery mode.
+	 *
+	 * In particular there was a hyperthreading cpu observed to
+	 * deliver interrupts to the wrong hyperthread when only one
+	 * hyperthread was specified in the interrupt desitination.
+	 */
+	cpumask_clear(retmask);
+	cpumask_bits(retmask)[0] = APIC_ALL_CPUS;
+}
+
+static inline void
+default_vector_allocation_domain(int cpu, struct cpumask *retmask)
+{
+	cpumask_copy(retmask, cpumask_of(cpu));
+}
+
 static inline unsigned long default_check_apicid_used(physid_mask_t *map, int apicid)
 {
 	return physid_isset(apicid, *map);