xen: Use this_cpu_ops

Use this_cpu_ops to reduce code size and simplify things in various places.

V3->V4:
	Move instance of this_cpu_inc_return to a later patchset so that
	this patch can be applied without infrastructure changes.

Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 31af0ac..a10c66d 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -355,7 +355,7 @@
 		struct evtchn_unmask unmask = { .port = port };
 		(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 	} else {
-		struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
+		struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 
 		sync_clear_bit(port, &s->evtchn_mask[0]);
 
@@ -1101,7 +1101,7 @@
 {
 	int cpu = get_cpu();
 	struct shared_info *s = HYPERVISOR_shared_info;
-	struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
  	unsigned count;
 
 	do {
@@ -1141,8 +1141,8 @@
 
 		BUG_ON(!irqs_disabled());
 
-		count = __get_cpu_var(xed_nesting_count);
-		__get_cpu_var(xed_nesting_count) = 0;
+		count = __this_cpu_read(xed_nesting_count);
+		__this_cpu_write(xed_nesting_count, 0);
 	} while (count != 1 || vcpu_info->evtchn_upcall_pending);
 
 out: