[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-xtensa/processor.h b/include/asm-xtensa/processor.h
index d1d72ad..8b96e77 100644
--- a/include/asm-xtensa/processor.h
+++ b/include/asm-xtensa/processor.h
@@ -20,6 +20,7 @@
#include <xtensa/config/tie.h>
#include <xtensa/config/system.h>
+#include <linux/compiler.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/coprocessor.h>
@@ -191,7 +192,7 @@
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
-#define cpu_relax() do { } while (0)
+#define cpu_relax() barrier()
/* Special register access. */
