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>

4 files changed, 7 insertions, 7 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index dcb38f8ddfda..a765b823aa9e 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -746,7 +746,7 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
         struct acpi_processor *pr;
         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
 
-        pr = __get_cpu_var(processors);
+        pr = __this_cpu_read(processors);
 
         if (unlikely(!pr))
                 return 0;
@@ -787,7 +787,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
         s64 idle_time_ns;
         s64 idle_time;
 
-        pr = __get_cpu_var(processors);
+        pr = __this_cpu_read(processors);
 
         if (unlikely(!pr))
                 return 0;
@@ -864,7 +864,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
         s64 idle_time;
 
 
-        pr = __get_cpu_var(processors);
+        pr = __this_cpu_read(processors);
 
         if (unlikely(!pr))
                 return 0;
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index a50710843378..978ff292a3fa 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -49,7 +49,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev);
  */
 static void cpuidle_idle_call(void)
 {
-        struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices);
+        struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
         struct cpuidle_state *target_state;
         int next_state;
 
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();
diff --git a/drivers/staging/speakup/fakekey.c b/drivers/staging/speakup/fakekey.c
index 65b231178f05..bf4ec68ac2eb 100644
--- a/drivers/staging/speakup/fakekey.c
+++ b/drivers/staging/speakup/fakekey.c
@@ -78,10 +78,10 @@ void speakup_fake_down_arrow(void)
         /* don't change CPU */
         preempt_disable();
 
-        __get_cpu_var(reporting_keystroke) = true;
+        __this_cpu_write(reporting_keystroke, true);
         input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
         input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
-        __get_cpu_var(reporting_keystroke) = false;
+        __this_cpu_write(reporting_keystroke, false);
 
         /* reenable preemption */
         preempt_enable();