[PATCH] CHECK_IRQ_PER_CPU() to avoid dead code in __do_IRQ()

IRQ_PER_CPU is not used by all architectures.  This patch introduces the
macros ARCH_HAS_IRQ_PER_CPU and CHECK_IRQ_PER_CPU() to avoid the generation
of dead code in __do_IRQ().

ARCH_HAS_IRQ_PER_CPU is defined by architectures using IRQ_PER_CPU in their
include/asm_ARCH/irq.h file.

Through grepping the tree I found the following architectures currently use
IRQ_PER_CPU:

        cris, ia64, ppc, ppc64 and parisc.

Signed-off-by: Karsten Wiese <annabellesgarden@yahoo.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 4a362b9ec96..69681c3b1f0 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -32,7 +32,12 @@
 #define IRQ_WAITING     32      /* IRQ not yet seen - for autodetection */
 #define IRQ_LEVEL       64      /* IRQ level triggered */
 #define IRQ_MASKED      128     /* IRQ masked - shouldn't be seen again */
-#define IRQ_PER_CPU     256     /* IRQ is per CPU */
+#if defined(ARCH_HAS_IRQ_PER_CPU)
+# define IRQ_PER_CPU    256     /* IRQ is per CPU */
+# define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)
+#else
+# define CHECK_IRQ_PER_CPU(var) 0
+#endif
 
 /*
  * Interrupt controller descriptor. This is all we need