[PATCH] Make cpu_relax() imply barrier() on all arches
During the recent discussion of taking 'volatile' off of the spinlock, I
noticed that while most arches #define cpu_relax() such that it implies
barrier(), some arches define cpu_relax() to be empty.
This patch changes the definition of cpu_relax() for frv, h8300, m68knommu,
sh, sh64, v850 and xtensa from an empty while(0) to the compiler barrier().
Signed-off-by: Chase Venters <chase.venters@clientec.com>
Acked-by: Arjan van de Ven <arjan@Linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-sh/processor.h b/include/asm-sh/processor.h
index fa5bd2d..eeb0f48 100644
--- a/include/asm-sh/processor.h
+++ b/include/asm-sh/processor.h
@@ -9,6 +9,7 @@
#define __ASM_SH_PROCESSOR_H
#ifdef __KERNEL__
+#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/types.h>
#include <asm/cache.h>
@@ -263,7 +264,7 @@
#define KSTK_ESP(tsk) ((tsk)->thread.sp)
#define cpu_sleep() __asm__ __volatile__ ("sleep" : : : "memory")
-#define cpu_relax() do { } while (0)
+#define cpu_relax() barrier()
#endif /* __KERNEL__ */
#endif /* __ASM_SH_PROCESSOR_H */