drivers: Replace __get_cpu_var with __this_cpu_read if not used for an address.

__get_cpu_var() can be replaced with this_cpu_read and will then use a single
read instruction with implied address calculation to access the correct per cpu
instance.

However, the address of a per cpu variable passed to __this_cpu_read() cannot be
determed (since its an implied address conversion through segment prefixes).
Therefore apply this only to uses of __get_cpu_var where the addres of the
variable is not used.

V3->V4:
	- Move one instance of this_cpu_inc_return to a later patch
	  so that this one can go in without percpu infrastructrure
	  changes.

Sedat: fixed compile failure caused by an extra ')'.

Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sedat Dilek <sedat.dilek@gmail.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>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index f4e6cf3aceb8..430f875006f2 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -619,7 +619,7 @@ void __irq_entry do_IRQ(struct pt_regs *regs)
 	s390_idle_check(regs, S390_lowcore.int_clock,
 			S390_lowcore.async_enter_timer);
 	irq_enter();
-	__get_cpu_var(s390_idle).nohz_delay = 1;
+	__this_cpu_write(s390_idle.nohz_delay, 1);
 	if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 		/* Serve timer interrupts first. */
 		clock_comparator_work();