[PATCH] unbreak alpha percpu

[Al Viro <viro@ZenIV.linux.org.uk>]

asm-generic/percpu.h is *NOT* included by every asm/percpu.h out there.
Namely, alpha can't use it since it needs the var name in
SHIFT_PERCPU_PTR - &per_cpu_var(var) won't do at all.  So adding stuff
to asm-generic/percpu.h and expecting it to be picked by everything
is not going to work.

Frankly, I'd rather have SHIFT_PERCPU_PTR() calling conventions changed,
but for now the patch below will do.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
diff --git a/arch/alpha/include/asm/percpu.h b/arch/alpha/include/asm/percpu.h
index 3495e8e..fffec74 100644
--- a/arch/alpha/include/asm/percpu.h
+++ b/arch/alpha/include/asm/percpu.h
@@ -75,4 +75,30 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 
 #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name)
 
+# define percpu_read(var)						\
+  ({									\
+	typeof(per_cpu_var(var)) __tmp_var__;				\
+	__tmp_var__ = get_cpu_var(var);					\
+	put_cpu_var(var);						\
+	__tmp_var__;							\
+  })
+
+#define __percpu_generic_to_op(var, val, op)				\
+do {									\
+	get_cpu_var(var) op val;					\
+	put_cpu_var(var);						\
+} while (0)
+
+# define percpu_write(var, val)		__percpu_generic_to_op(var, (val), =)
+
+# define percpu_add(var, val)		__percpu_generic_to_op(var, (val), +=)
+
+# define percpu_sub(var, val)		__percpu_generic_to_op(var, (val), -=)
+
+# define percpu_and(var, val)		__percpu_generic_to_op(var, (val), &=)
+
+# define percpu_or(var, val)		__percpu_generic_to_op(var, (val), |=)
+
+# define percpu_xor(var, val)		__percpu_generic_to_op(var, (val), ^=)
+
 #endif /* __ALPHA_PERCPU_H */