Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.
This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/ia64/include/asm/atomic.h | 134 +++++++++++++++++++++++++++++++++++------
1 file changed, 116 insertions(+), 18 deletions(-)
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -42,8 +42,27 @@ ia64_atomic_##op (int i, atomic_t *v)
return new; \
}
-ATOMIC_OP(add, +)
-ATOMIC_OP(sub, -)
+#define ATOMIC_FETCH_OP(op, c_op) \
+static __inline__ int \
+ia64_atomic_fetch_##op (int i, atomic_t *v) \
+{ \
+ __s32 old, new; \
+ CMPXCHG_BUGCHECK_DECL \
+ \
+ do { \
+ CMPXCHG_BUGCHECK(v); \
+ old = atomic_read(v); \
+ new = old c_op i; \
+ } while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic_t)) != old); \
+ return old; \
+}
+
+#define ATOMIC_OPS(op, c_op) \
+ ATOMIC_OP(op, c_op) \
+ ATOMIC_FETCH_OP(op, c_op)
+
+ATOMIC_OPS(add, +)
+ATOMIC_OPS(sub, -)
#define atomic_add_return(i,v) \
({ \
@@ -69,14 +88,44 @@ ATOMIC_OP(sub, -)
: ia64_atomic_sub(__ia64_asr_i, v); \
})
-ATOMIC_OP(and, &)
-ATOMIC_OP(or, |)
-ATOMIC_OP(xor, ^)
-
-#define atomic_and(i,v) (void)ia64_atomic_and(i,v)
-#define atomic_or(i,v) (void)ia64_atomic_or(i,v)
-#define atomic_xor(i,v) (void)ia64_atomic_xor(i,v)
+#define atomic_fetch_add(i,v) \
+({ \
+ int __ia64_aar_i = (i); \
+ (__builtin_constant_p(i) \
+ && ( (__ia64_aar_i == 1) || (__ia64_aar_i == 4) \
+ || (__ia64_aar_i == 8) || (__ia64_aar_i == 16) \
+ || (__ia64_aar_i == -1) || (__ia64_aar_i == -4) \
+ || (__ia64_aar_i == -8) || (__ia64_aar_i == -16))) \
+ ? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq) \
+ : ia64_atomic_fetch_add(__ia64_aar_i, v); \
+})
+
+#define atomic_fetch_sub(i,v) \
+({ \
+ int __ia64_asr_i = (i); \
+ (__builtin_constant_p(i) \
+ && ( (__ia64_asr_i == 1) || (__ia64_asr_i == 4) \
+ || (__ia64_asr_i == 8) || (__ia64_asr_i == 16) \
+ || (__ia64_asr_i == -1) || (__ia64_asr_i == -4) \
+ || (__ia64_asr_i == -8) || (__ia64_asr_i == -16))) \
+ ? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq) \
+ : ia64_atomic_fetch_sub(__ia64_asr_i, v); \
+})
+ATOMIC_FETCH_OP(and, &)
+ATOMIC_FETCH_OP(or, |)
+ATOMIC_FETCH_OP(xor, ^)
+
+#define atomic_and(i,v) (void)ia64_atomic_fetch_and(i,v)
+#define atomic_or(i,v) (void)ia64_atomic_fetch_or(i,v)
+#define atomic_xor(i,v) (void)ia64_atomic_fetch_xor(i,v)
+
+#define atomic_fetch_and(i,v) ia64_atomic_fetch_and(i,v)
+#define atomic_fetch_or(i,v) ia64_atomic_fetch_or(i,v)
+#define atomic_fetch_xor(i,v) ia64_atomic_fetch_xor(i,v)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP
#define ATOMIC64_OP(op, c_op) \
@@ -94,8 +143,27 @@ ia64_atomic64_##op (__s64 i, atomic64_t
return new; \
}
-ATOMIC64_OP(add, +)
-ATOMIC64_OP(sub, -)
+#define ATOMIC64_FETCH_OP(op, c_op) \
+static __inline__ long \
+ia64_atomic64_fetch_##op (__s64 i, atomic64_t *v) \
+{ \
+ __s64 old, new; \
+ CMPXCHG_BUGCHECK_DECL \
+ \
+ do { \
+ CMPXCHG_BUGCHECK(v); \
+ old = atomic64_read(v); \
+ new = old c_op i; \
+ } while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic64_t)) != old); \
+ return old; \
+}
+
+#define ATOMIC64_OPS(op, c_op) \
+ ATOMIC64_OP(op, c_op) \
+ ATOMIC64_FETCH_OP(op, c_op)
+
+ATOMIC64_OPS(add, +)
+ATOMIC64_OPS(sub, -)
#define atomic64_add_return(i,v) \
({ \
@@ -121,14 +189,44 @@ ATOMIC64_OP(sub, -)
: ia64_atomic64_sub(__ia64_asr_i, v); \
})
-ATOMIC64_OP(and, &)
-ATOMIC64_OP(or, |)
-ATOMIC64_OP(xor, ^)
-
-#define atomic64_and(i,v) (void)ia64_atomic64_and(i,v)
-#define atomic64_or(i,v) (void)ia64_atomic64_or(i,v)
-#define atomic64_xor(i,v) (void)ia64_atomic64_xor(i,v)
+#define atomic64_fetch_add(i,v) \
+({ \
+ long __ia64_aar_i = (i); \
+ (__builtin_constant_p(i) \
+ && ( (__ia64_aar_i == 1) || (__ia64_aar_i == 4) \
+ || (__ia64_aar_i == 8) || (__ia64_aar_i == 16) \
+ || (__ia64_aar_i == -1) || (__ia64_aar_i == -4) \
+ || (__ia64_aar_i == -8) || (__ia64_aar_i == -16))) \
+ ? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq) \
+ : ia64_atomic64_fetch_add(__ia64_aar_i, v); \
+})
+
+#define atomic64_fetch_sub(i,v) \
+({ \
+ long __ia64_asr_i = (i); \
+ (__builtin_constant_p(i) \
+ && ( (__ia64_asr_i == 1) || (__ia64_asr_i == 4) \
+ || (__ia64_asr_i == 8) || (__ia64_asr_i == 16) \
+ || (__ia64_asr_i == -1) || (__ia64_asr_i == -4) \
+ || (__ia64_asr_i == -8) || (__ia64_asr_i == -16))) \
+ ? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq) \
+ : ia64_atomic64_fetch_sub(__ia64_asr_i, v); \
+})
+
+ATOMIC64_FETCH_OP(and, &)
+ATOMIC64_FETCH_OP(or, |)
+ATOMIC64_FETCH_OP(xor, ^)
+
+#define atomic64_and(i,v) (void)ia64_atomic64_fetch_and(i,v)
+#define atomic64_or(i,v) (void)ia64_atomic64_fetch_or(i,v)
+#define atomic64_xor(i,v) (void)ia64_atomic64_fetch_xor(i,v)
+
+#define atomic64_fetch_and(i,v) ia64_atomic64_fetch_and(i,v)
+#define atomic64_fetch_or(i,v) ia64_atomic64_fetch_or(i,v)
+#define atomic64_fetch_xor(i,v) ia64_atomic64_fetch_xor(i,v)
+#undef ATOMIC64_OPS
+#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
--
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