diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2020-08-29 16:03:35 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-10-12 19:27:27 +0300 |
| commit | 29f006fdefe6f88abde973a0b0f20d2704e93fd4 (patch) | |
| tree | 11df0a506bb05fdd72c07a4fed5bbdb80b3b7bf5 /include/linux/atomic-fallback.h | |
| parent | d741bf41d7c7db4898bacfcb020353cddc032fd8 (diff) | |
| download | linux-29f006fdefe6f88abde973a0b0f20d2704e93fd4.tar.xz | |
asm-generic/atomic: Add try_cmpxchg() fallbacks
Only x86 provides try_cmpxchg() outside of the atomic_t interfaces,
provide generic fallbacks to create this interface from the widely
available cmpxchg() function.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/159870621515.1229682.15506193091065001742.stgit@devnote2
Diffstat (limited to 'include/linux/atomic-fallback.h')
| -rw-r--r-- | include/linux/atomic-fallback.h | 90 |
1 files changed, 80 insertions, 10 deletions
diff --git a/include/linux/atomic-fallback.h b/include/linux/atomic-fallback.h index fd525c71d676..2a3f55d98be9 100644 --- a/include/linux/atomic-fallback.h +++ b/include/linux/atomic-fallback.h @@ -9,9 +9,9 @@ #include <linux/compiler.h> #ifndef xchg_relaxed -#define xchg_relaxed xchg -#define xchg_acquire xchg -#define xchg_release xchg +#define xchg_acquire xchg +#define xchg_release xchg +#define xchg_relaxed xchg #else /* xchg_relaxed */ #ifndef xchg_acquire @@ -32,9 +32,9 @@ #endif /* xchg_relaxed */ #ifndef cmpxchg_relaxed -#define cmpxchg_relaxed cmpxchg -#define cmpxchg_acquire cmpxchg -#define cmpxchg_release cmpxchg +#define cmpxchg_acquire cmpxchg +#define cmpxchg_release cmpxchg +#define cmpxchg_relaxed cmpxchg #else /* cmpxchg_relaxed */ #ifndef cmpxchg_acquire @@ -55,9 +55,9 @@ #endif /* cmpxchg_relaxed */ #ifndef cmpxchg64_relaxed -#define cmpxchg64_relaxed cmpxchg64 -#define cmpxchg64_acquire cmpxchg64 -#define cmpxchg64_release cmpxchg64 +#define cmpxchg64_acquire cmpxchg64 +#define cmpxchg64_release cmpxchg64 +#define cmpxchg64_relaxed cmpxchg64 #else /* cmpxchg64_relaxed */ #ifndef cmpxchg64_acquire @@ -77,6 +77,76 @@ #endif /* cmpxchg64_relaxed */ +#ifndef try_cmpxchg_relaxed +#ifdef try_cmpxchg +#define try_cmpxchg_acquire try_cmpxchg +#define try_cmpxchg_release try_cmpxchg +#define try_cmpxchg_relaxed try_cmpxchg +#endif /* try_cmpxchg */ + +#ifndef try_cmpxchg +#define try_cmpxchg(_ptr, _oldp, _new) \ +({ \ + typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + ___r = cmpxchg((_ptr), ___o, (_new)); \ + if (unlikely(___r != ___o)) \ + *___op = ___r; \ + likely(___r == ___o); \ +}) +#endif /* try_cmpxchg */ + +#ifndef try_cmpxchg_acquire +#define try_cmpxchg_acquire(_ptr, _oldp, _new) \ +({ \ + typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + ___r = cmpxchg_acquire((_ptr), ___o, (_new)); \ + if (unlikely(___r != ___o)) \ + *___op = ___r; \ + likely(___r == ___o); \ +}) +#endif /* try_cmpxchg_acquire */ + +#ifndef try_cmpxchg_release +#define try_cmpxchg_release(_ptr, _oldp, _new) \ +({ \ + typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + ___r = cmpxchg_release((_ptr), ___o, (_new)); \ + if (unlikely(___r != ___o)) \ + *___op = ___r; \ + likely(___r == ___o); \ +}) +#endif /* try_cmpxchg_release */ + +#ifndef try_cmpxchg_relaxed +#define try_cmpxchg_relaxed(_ptr, _oldp, _new) \ +({ \ + typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + ___r = cmpxchg_relaxed((_ptr), ___o, (_new)); \ + if (unlikely(___r != ___o)) \ + *___op = ___r; \ + likely(___r == ___o); \ +}) +#endif /* try_cmpxchg_relaxed */ + +#else /* try_cmpxchg_relaxed */ + +#ifndef try_cmpxchg_acquire +#define try_cmpxchg_acquire(...) \ + __atomic_op_acquire(try_cmpxchg, __VA_ARGS__) +#endif + +#ifndef try_cmpxchg_release +#define try_cmpxchg_release(...) \ + __atomic_op_release(try_cmpxchg, __VA_ARGS__) +#endif + +#ifndef try_cmpxchg +#define try_cmpxchg(...) \ + __atomic_op_fence(try_cmpxchg, __VA_ARGS__) +#endif + +#endif /* try_cmpxchg_relaxed */ + #define arch_atomic_read atomic_read #define arch_atomic_read_acquire atomic_read_acquire @@ -2522,4 +2592,4 @@ atomic64_dec_if_positive(atomic64_t *v) #endif #endif /* _LINUX_ATOMIC_FALLBACK_H */ -// 9d95b56f98d82a2a26c7b79ccdd0c47572d50a6f +// d78e6c293c661c15188f0ec05bce45188c8d5892 |