[PATCH] alpha: atomic dependency fix

My alpha build is exploding because asm/atomic.h now needs smb_mb(), which is
over in the (not included) system.h.

I fear what will happen if I include system.h into atomic.h, so let's put the
barriers into their own header file.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-alpha/atomic.h

@@ -1,6 +1,8 @@
 #ifndef _ALPHA_ATOMIC_H
 #define _ALPHA_ATOMIC_H
 
+#include <asm/barrier.h>
+
 /*
  * Atomic operations that C can't guarantee us.  Useful for
  * resource counting etc...

include/asm-alpha/barrier.h

@@ -0,0 +1,34 @@
+#ifndef __BARRIER_H
+#define __BARRIER_H
+
+#define mb() \
+__asm__ __volatile__("mb": : :"memory")
+
+#define rmb() \
+__asm__ __volatile__("mb": : :"memory")
+
+#define wmb() \
+__asm__ __volatile__("wmb": : :"memory")
+
+#define read_barrier_depends() \
+__asm__ __volatile__("mb": : :"memory")
+
+#ifdef CONFIG_SMP
+#define smp_mb()	mb()
+#define smp_rmb()	rmb()
+#define smp_wmb()	wmb()
+#define smp_read_barrier_depends()	read_barrier_depends()
+#else
+#define smp_mb()	barrier()
+#define smp_rmb()	barrier()
+#define smp_wmb()	barrier()
+#define smp_read_barrier_depends()	barrier()
+#endif
+
+#define set_mb(var, value) \
+do { var = value; mb(); } while (0)
+
+#define set_wmb(var, value) \
+do { var = value; wmb(); } while (0)
+
+#endif		/* __BARRIER_H */

include/asm-alpha/system.h

@@ -4,6 +4,7 @@
 #include <linux/config.h>
 #include <asm/pal.h>
 #include <asm/page.h>
+#include <asm/barrier.h>
 
 /*
  * System defines.. Note that this is included both from .c and .S
@@ -139,36 +140,6 @@ extern void halt(void) __attribute__((noreturn));
 struct task_struct;
 extern struct task_struct *alpha_switch_to(unsigned long, struct task_struct*);
 
-#define mb() \
-__asm__ __volatile__("mb": : :"memory")
-
-#define rmb() \
-__asm__ __volatile__("mb": : :"memory")
-
-#define wmb() \
-__asm__ __volatile__("wmb": : :"memory")
-
-#define read_barrier_depends() \
-__asm__ __volatile__("mb": : :"memory")
-
-#ifdef CONFIG_SMP
-#define smp_mb()	mb()
-#define smp_rmb()	rmb()
-#define smp_wmb()	wmb()
-#define smp_read_barrier_depends()	read_barrier_depends()
-#else
-#define smp_mb()	barrier()
-#define smp_rmb()	barrier()
-#define smp_wmb()	barrier()
-#define smp_read_barrier_depends()	barrier()
-#endif
-
-#define set_mb(var, value) \
-do { var = value; mb(); } while (0)
-
-#define set_wmb(var, value) \
-do { var = value; wmb(); } while (0)
-
 #define imb() \
 __asm__ __volatile__ ("call_pal %0 #imb" : : "i" (PAL_imb) : "memory")