diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2018-06-21 13:13:09 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-06-21 14:22:33 +0200 |
| commit | eccc2da8c03f316bba202e15af2be4615f461900 (patch) | |
| tree | 1efd0bf1e8620a33ed58cd74cacc94ffc8cf111f /include/asm-generic | |
| parent | bef828204a1bc7a0fd3a24551c4265e9c2ab95ed (diff) | |
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
<linux/atomic.h>, 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 <mark.rutland@arm.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Palmer Dabbelt <palmer@sifive.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Link: https://lore.kernel.org/lkml/20180621121321.4761-7-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/atomic-instrumented.h | 4 | ||||
| -rw-r--r-- | include/asm-generic/atomic.h | 11 |
2 files changed, 3 insertions, 12 deletions
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 */ |