softirq/core: Consolidate default local_softirq_pending() implementations

Consolidate and optimize default softirq mask API implementations.
Per-CPU operations are expected to be faster and a few architectures
already rely on them to implement local_softirq_pending() and related
accessors/mutators. Those will be migrated to the new generic code.

Signed-off-by: Frederic Weisbecker <[e-mail]>
Acked-by: Thomas Gleixner <[e-mail]>
Acked-by: Peter Zijlstra <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Fenghua Yu <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Helge Deller <[e-mail]>
Cc: James E.J. Bottomley <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Sebastian Andrzej Siewior <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

include/linux/interrupt.h

···
 #define force_irqthreads	(0)
 #endif
 
+#ifndef local_softirq_pending
+
+#ifndef local_softirq_pending_ref
+#define local_softirq_pending_ref irq_stat.__softirq_pending
+#endif
+
+#define local_softirq_pending()	(__this_cpu_read(local_softirq_pending_ref))
+#define set_softirq_pending(x)	(__this_cpu_write(local_softirq_pending_ref, (x)))
+#define or_softirq_pending(x)	(__this_cpu_or(local_softirq_pending_ref, (x)))
+
+#else /* local_softirq_pending */
+
 #ifndef __ARCH_SET_SOFTIRQ_PENDING
 #define set_softirq_pending(x) (local_softirq_pending() = (x))
 #define or_softirq_pending(x)  (local_softirq_pending() |= (x))
 #endif
+
+#endif /* local_softirq_pending */
 
 /* Some architectures might implement lazy enabling/disabling of
  * interrupts. In some cases, such as stop_machine, we might want

include/linux/irq_cpustat.h

···
 #define __IRQ_STAT(cpu, member)	(per_cpu(irq_stat.member, cpu))
 #endif
 
-  /* arch independent irq_stat fields */
-#define local_softirq_pending() \
-	__IRQ_STAT(smp_processor_id(), __softirq_pending)
-
-  /* arch dependent irq_stat fields */
+/* arch dependent irq_stat fields */
 #define nmi_count(cpu)		__IRQ_STAT((cpu), __nmi_count)	/* i386 */
 
 #endif	/* __irq_cpustat_h */