include/linux/smp.h:on_each_cpu(): switch back to a macro

Commit f21afc25f9ed ("smp.h: Use local_irq_{save,restore}() in !SMP
version of on_each_cpu()") converted on_each_cpu() to a C function.

This required inclusion of irqflags.h, which broke ia64 and mn10300 (at
least) due to header ordering hell.

Switch on_each_cpu() back to a macro to fix this.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: <stable@vger.kernel.org>	[3.10.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/smp.h

@@ -11,7 +11,6 @@
 #include <linux/list.h>
 #include <linux/cpumask.h>
 #include <linux/init.h>
-#include <linux/irqflags.h>
 
 extern void cpu_idle(void);
 
@@ -140,17 +139,14 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info)
 }
 #define smp_call_function(func, info, wait) \
 			(up_smp_call_function(func, info))
-
-static inline int on_each_cpu(smp_call_func_t func, void *info, int wait)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	func(info);
-	local_irq_restore(flags);
-	return 0;
-}
-
+#define on_each_cpu(func, info, wait)		\
+	({					\
+		unsigned long __flags;		\
+		local_irq_save(__flags);	\
+		func(info);			\
+		local_irq_restore(__flags);	\
+		0;				\
+	})
 /*
  * Note we still need to test the mask even for UP
  * because we actually can get an empty mask from