sched/irqtime: No need for preempt-safe accessors

We can safely use the preempt-unsafe accessors for irqtime when we
flush its counters to kcpustat as IRQs are disabled at this time.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/cputime.c

@@ -82,7 +82,7 @@ static cputime_t irqtime_account_hi_update(cputime_t maxtime)
 	cputime_t irq_cputime;
 
 	local_irq_save(flags);
-	irq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)) -
+	irq_cputime = nsecs_to_cputime64(__this_cpu_read(cpu_hardirq_time)) -
 		      cpustat[CPUTIME_IRQ];
 	irq_cputime = min(irq_cputime, maxtime);
 	cpustat[CPUTIME_IRQ] += irq_cputime;
@@ -97,7 +97,7 @@ static cputime_t irqtime_account_si_update(cputime_t maxtime)
 	cputime_t softirq_cputime;
 
 	local_irq_save(flags);
-	softirq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)) -
+	softirq_cputime = nsecs_to_cputime64(__this_cpu_read(cpu_softirq_time)) -
 			  cpustat[CPUTIME_SOFTIRQ];
 	softirq_cputime = min(softirq_cputime, maxtime);
 	cpustat[CPUTIME_SOFTIRQ] += softirq_cputime;