[PATCH 06/20] arch,avr32: Fold atomic_ops

From: Peter Zijlstra
Date: Thu May 08 2014 - 10:04:59 EST


Many of the atomic op implementations are the same except for one
instruction; fold the lot into a few CPP macros and reduce LoC.

This also prepares for easy addition of new ops.

Requires the asm_op because of eor.

Cc: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
Cc: Hans-Christian Egtvedt <egtvedt@xxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
arch/avr32/include/asm/atomic.h | 96 ++++++++++++++++++----------------------
1 file changed, 44 insertions(+), 52 deletions(-)

--- a/arch/avr32/include/asm/atomic.h
+++ b/arch/avr32/include/asm/atomic.h
@@ -22,58 +22,52 @@
#define atomic_read(v) (*(volatile int *)&(v)->counter)
#define atomic_set(v, i) (((v)->counter) = i)

-/*
- * atomic_sub_return - subtract the atomic variable
- * @i: integer value to subtract
- * @v: pointer of type atomic_t
- *
- * Atomically subtracts @i from @v. Returns the resulting value.
- */
-static inline int atomic_sub_return(int i, atomic_t *v)
-{
- int result;
-
- asm volatile(
- "/* atomic_sub_return */\n"
- "1: ssrf 5\n"
- " ld.w %0, %2\n"
- " sub %0, %3\n"
- " stcond %1, %0\n"
- " brne 1b"
- : "=&r"(result), "=o"(v->counter)
- : "m"(v->counter), "rKs21"(i)
- : "cc");
-
- return result;
+#define ATOMIC_OP(op, asm_op) \
+static inline void atomic_##op(int i, atomic_t *v) \
+{ \
+ int result; \
+ \
+ asm volatile( \
+ "/* atomic_" #op " */\n" \
+ "1: ssrf 5\n" \
+ " ld.w %0, %2\n" \
+ " " #asm_op " %0, %3\n" \
+ " stcond %1, %0\n" \
+ " brne 1b" \
+ : "=&r"(result), "=o"(v->counter) \
+ : "m"(v->counter), "rKs21"(i) \
+ : "cc"); \
+} \
+
+#define ATOMIC_OP_RETURN(op, asm_op) \
+static inline int atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ int result; \
+ \
+ asm volatile( \
+ "/* atomic_" #op "_return */\n" \
+ "1: ssrf 5\n" \
+ " ld.w %0, %2\n" \
+ " " #asm_op " %0, %3\n" \
+ " stcond %1, %0\n" \
+ " brne 1b" \
+ : "=&r"(result), "=o"(v->counter) \
+ : "m"(v->counter), "rKs21"(i) \
+ : "cc"); \
+ \
+ return result; \
}

-/*
- * atomic_add_return - add integer to atomic variable
- * @i: integer value to add
- * @v: pointer of type atomic_t
- *
- * Atomically adds @i to @v. Returns the resulting value.
- */
-static inline int atomic_add_return(int i, atomic_t *v)
-{
- int result;
-
- if (__builtin_constant_p(i) && (i >= -1048575) && (i <= 1048576))
- result = atomic_sub_return(-i, v);
- else
- asm volatile(
- "/* atomic_add_return */\n"
- "1: ssrf 5\n"
- " ld.w %0, %1\n"
- " add %0, %3\n"
- " stcond %2, %0\n"
- " brne 1b"
- : "=&r"(result), "=o"(v->counter)
- : "m"(v->counter), "r"(i)
- : "cc", "memory");
-
- return result;
-}
+#define ATOMIC_OPS(op, asm_op) \
+ ATOMIC_OP(op, asm_op) \
+ ATOMIC_OP_RETURN(op, asm_op)
+
+ATOMIC_OPS(add, add)
+ATOMIC_OPS(sub, sub)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP

/*
* atomic_sub_unless - sub unless the number is a given value
@@ -168,8 +162,6 @@ static inline int atomic_sub_if_positive
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))

-#define atomic_sub(i, v) (void)atomic_sub_return(i, v)
-#define atomic_add(i, v) (void)atomic_add_return(i, v)
#define atomic_dec(v) atomic_sub(1, (v))
#define atomic_inc(v) atomic_add(1, (v))



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