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/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b2bb5aa..ef8930f 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -135,24 +135,24 @@
 
 	/* Add the appropriate number of ticks of stolen time,
 	   including any left-overs from last time. */
-	stolen = runnable + offline + __get_cpu_var(xen_residual_stolen);
+	stolen = runnable + offline + __this_cpu_read(xen_residual_stolen);
 
 	if (stolen < 0)
 		stolen = 0;
 
 	ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen);
-	__get_cpu_var(xen_residual_stolen) = stolen;
+	__this_cpu_write(xen_residual_stolen, stolen);
 	account_steal_ticks(ticks);
 
 	/* Add the appropriate number of ticks of blocked time,
 	   including any left-overs from last time. */
-	blocked += __get_cpu_var(xen_residual_blocked);
+	blocked += __this_cpu_read(xen_residual_blocked);
 
 	if (blocked < 0)
 		blocked = 0;
 
 	ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked);
-	__get_cpu_var(xen_residual_blocked) = blocked;
+	__this_cpu_write(xen_residual_blocked, blocked);
 	account_idle_ticks(ticks);
 }