Re: [PATCH] unbreak alpha percpu

Tejun Heo
2009-04-10T19:03:49Z

Long term, I think what Ivan proposed with a bit of addition so that
combination of DECLARE_PER_CPU() and static DEFINE_PER_CPU() triggers
compile error but I think it's better to do it when converting non-x86
archs to dynamic percpu allocator which is scheduled for the next
merge window. For the time being, how about just moving the generic
percpu_*() accessors to linux/percpu.h? asm-generic/percpu.h is meant
to carry generic stuff for low level stuff - declarations, definitions
and pointer offset calculation and so on but not for generic
interface.

I currently can't build or test stuff so the patch is not tested at
all. Ingo, can you please test whether this would work?

Thanks.
---
include/asm-generic/percpu.h | 52 -------------------------------------------
include/linux/percpu.h | 52 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 52 insertions(+), 52 deletions(-)

diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 00f45ff..b0e63c6 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -80,56 +80,4 @@ extern void setup_per_cpu_areas(void);
#define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \
__typeof__(type) per_cpu_var(name)

-/*
- * Optional methods for optimized non-lvalue per-cpu variable access.
- *
- * @var can be a percpu variable or a field of it and its size should
- * equal char, int or long. percpu_read() evaluates to a lvalue and
- * all others to void.
- *
- * These operations are guaranteed to be atomic w.r.t. preemption.
- * The generic versions use plain get/put_cpu_var(). Archs are
- * encouraged to implement single-instruction alternatives which don't
- * require preemption protection.
- */
-#ifndef percpu_read
-# define percpu_read(var) \
- ({ \
- typeof(per_cpu_var(var)) __tmp_var__; \
- __tmp_var__ = get_cpu_var(var); \
- put_cpu_var(var); \
- __tmp_var__; \
- })
-#endif
-
-#define __percpu_generic_to_op(var, val, op) \
-do { \
- get_cpu_var(var) op val; \
- put_cpu_var(var); \
-} while (0)
-
-#ifndef percpu_write
-# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
-#endif
-
-#ifndef percpu_add
-# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
-#endif
-
-#ifndef percpu_sub
-# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
-#endif
-
-#ifndef percpu_and
-# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
-#endif
-
-#ifndef percpu_or
-# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
-#endif
-
-#ifndef percpu_xor
-# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
-#endif
-
#endif /* _ASM_GENERIC_PERCPU_H_ */
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index ee5615d..cfda2d5 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -168,4 +168,56 @@ static inline void free_percpu(void *p)
#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
__alignof__(type))

+/*
+ * Optional methods for optimized non-lvalue per-cpu variable access.
+ *
+ * @var can be a percpu variable or a field of it and its size should
+ * equal char, int or long. percpu_read() evaluates to a lvalue and
+ * all others to void.
+ *
+ * These operations are guaranteed to be atomic w.r.t. preemption.
+ * The generic versions use plain get/put_cpu_var(). Archs are
+ * encouraged to implement single-instruction alternatives which don't
+ * require preemption protection.
+ */
+#ifndef percpu_read
+# define percpu_read(var) \
+ ({ \
+ typeof(per_cpu_var(var)) __tmp_var__; \
+ __tmp_var__ = get_cpu_var(var); \
+ put_cpu_var(var); \
+ __tmp_var__; \
+ })
+#endif
+
+#define __percpu_generic_to_op(var, val, op) \
+do { \
+ get_cpu_var(var) op val; \
+ put_cpu_var(var); \
+} while (0)
+
+#ifndef percpu_write
+# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
+#endif
+
+#ifndef percpu_add
+# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
+#endif
+
+#ifndef percpu_sub
+# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
+#endif
+
+#ifndef percpu_and
+# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
+#endif
+
+#ifndef percpu_or
+# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
+#endif
+
+#ifndef percpu_xor
+# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
+#endif
+
#endif /* __LINUX_PERCPU_H */