From eccc2da8c03f316bba202e15af2be4615f461900 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 21 Jun 2018 13:13:09 +0100 Subject: atomics/treewide: Make atomic_fetch_add_unless() optional Several architectures these have a near-identical implementation based on atomic_read() and atomic_cmpxchg() which we can instead define in , so let's do so, using something close to the existing x86 implementation with try_cmpxchg(). Where an architecture provides its own atomic_fetch_add_unless(), it must define a preprocessor symbol for it. The instrumented atomics are updated accordingly. Note that arch/arc's existing atomic_fetch_add_unless() had redundant barriers, as these are already present in its atomic_cmpxchg() implementation. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Reviewed-by: Geert Uytterhoeven Reviewed-by: Will Deacon Acked-by: Geert Uytterhoeven Acked-by: Peter Zijlstra (Intel) Acked-by: Palmer Dabbelt Cc: Boqun Feng Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Vineet Gupta Link: https://lore.kernel.org/lkml/20180621121321.4761-7-mark.rutland@arm.com Signed-off-by: Ingo Molnar --- include/asm-generic/atomic-instrumented.h | 4 +++- include/asm-generic/atomic.h | 11 ----------- 2 files changed, 3 insertions(+), 12 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h index 83bb88d791c4..1f9b2a767d3c 100644 --- a/include/asm-generic/atomic-instrumented.h +++ b/include/asm-generic/atomic-instrumented.h @@ -84,12 +84,14 @@ static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 ne } #endif +#ifdef arch_atomic_fetch_add_unless +#define atomic_fetch_add_unless atomic_fetch_add_unless static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) { kasan_check_write(v, sizeof(*v)); return arch_atomic_fetch_add_unless(v, a, u); } - +#endif static __always_inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u) { diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index 10051ed6d088..757e45821220 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -221,15 +221,4 @@ static inline void atomic_dec(atomic_t *v) #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) -#ifndef atomic_fetch_add_unless -static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) -{ - int c, old; - c = atomic_read(v); - while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) - c = old; - return c; -} -#endif - #endif /* __ASM_GENERIC_ATOMIC_H */ -- cgit v1.2.1