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Subject[PATCH 05/12] percpu: reorganize include/linux/percpu-defs.h
Date
Reorganize for better readability.

* Accessor definitions are collected into one place and SMP and UP now
define them in the same order.

* Definitions are layered when possible - e.g. per_cpu() is now
defined in terms of this_cpu_ptr().

* Rather pointless comment dropped.

* per_cpu(), __raw_get_cpu_var() and __get_cpu_var() are defined in a
way which can be shared between SMP and UP and moved out of
CONFIG_SMP blocks.

This patch doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
---
include/linux/percpu-defs.h | 32 +++++++++-----------------------
1 file changed, 9 insertions(+), 23 deletions(-)

diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index f25bb94..bd86f46 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -224,15 +224,8 @@
RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
})

-/*
- * A percpu variable may point to a discarded regions. The following are
- * established ways to produce a usable pointer from the percpu variable
- * offset.
- */
-#define per_cpu(var, cpu) \
- (*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
-
-#define raw_cpu_ptr(ptr) arch_raw_cpu_ptr(ptr)
+#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
+#define raw_cpu_ptr(ptr) arch_raw_cpu_ptr(ptr)

#ifdef CONFIG_DEBUG_PREEMPT
#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
@@ -240,9 +233,6 @@
#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
#endif

-#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
-#define __raw_get_cpu_var(var) (*raw_cpu_ptr(&(var)))
-
#else /* CONFIG_SMP */

#define VERIFY_PERCPU_PTR(__p) ({ \
@@ -250,14 +240,16 @@
(typeof(*(__p)) __kernel __force *)(__p); \
})

-#define per_cpu(var, cpu) (*((void)(cpu), VERIFY_PERCPU_PTR(&(var))))
-#define __get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
-#define __raw_get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
-#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
-#define raw_cpu_ptr(ptr) this_cpu_ptr(ptr)
+#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
+#define raw_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
+#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)

#endif /* CONFIG_SMP */

+#define per_cpu(var, cpu) (*per_cpu_ptr(&(var), cpu))
+#define __raw_get_cpu_var(var) (*raw_cpu_ptr(&(var)))
+#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
+
/* keep until we have removed all uses of __this_cpu_ptr */
#define __this_cpu_ptr(ptr) raw_cpu_ptr(ptr)

@@ -287,11 +279,5 @@
preempt_enable(); \
} while (0)

-#ifdef CONFIG_SMP
-#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
-#else
-#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
-#endif
-
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_PERCPU_DEFS_H */
--
1.9.3


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