[PATCH v2 08/33] locking/atomic: atomic: simplify ifdeffery

From: Mark Rutland
Date: Tue May 25 2021 - 10:04:58 EST


Now that asm-generic/atomic.h is only used by architectures without any
architecture-specific atomic definitions, we know that there will be no
architecture-specific implementations to override, and can remove the
ifdeffery this has previously required, bringing it into line with
asm-generic/atomic64.h.

At the same time, we can implement atomic_add() and atomic_sub()
directly using ATOMIC_OP(), since we know architectures won't provide
atomic_add_return() or atomic_sub_return().

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
---
include/asm-generic/atomic.h | 46 ++++----------------------------------------
1 file changed, 4 insertions(+), 42 deletions(-)

diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index d4bf803d6491..316c82a27b0a 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -93,65 +93,27 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \

#endif /* CONFIG_SMP */

-#ifndef atomic_add_return
ATOMIC_OP_RETURN(add, +)
-#endif
-
-#ifndef atomic_sub_return
ATOMIC_OP_RETURN(sub, -)
-#endif

-#ifndef atomic_fetch_add
ATOMIC_FETCH_OP(add, +)
-#endif
-
-#ifndef atomic_fetch_sub
ATOMIC_FETCH_OP(sub, -)
-#endif
-
-#ifndef atomic_fetch_and
ATOMIC_FETCH_OP(and, &)
-#endif
-
-#ifndef atomic_fetch_or
ATOMIC_FETCH_OP(or, |)
-#endif
-
-#ifndef atomic_fetch_xor
ATOMIC_FETCH_OP(xor, ^)
-#endif

-#ifndef atomic_and
+ATOMIC_OP(add, +)
+ATOMIC_OP(sub, -)
ATOMIC_OP(and, &)
-#endif
-
-#ifndef atomic_or
ATOMIC_OP(or, |)
-#endif
-
-#ifndef atomic_xor
ATOMIC_OP(xor, ^)
-#endif

#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP

-#ifndef atomic_read
-#define atomic_read(v) READ_ONCE((v)->counter)
-#endif
-
-#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
-
-static inline void atomic_add(int i, atomic_t *v)
-{
- atomic_add_return(i, v);
-}
-
-static inline void atomic_sub(int i, atomic_t *v)
-{
- atomic_sub_return(i, v);
-}
+#define atomic_read(v) READ_ONCE((v)->counter)
+#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))

#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
--
2.11.0