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Subject[PATCH 06/13] atomics/generic: define atomic64_fetch_add_unless()
Date
As a step towards unifying the atomic/atomic64/atomic_long APIs, this
patch converts the generic implementation of atomic64_add_unless() into
a generic implementation of atomic64_fetch_add_unless().

A wrapper in <linux/atomic.h> will build atomic_add_unless() atop of
this, provided it is given a preprocessor definition.

No functional change is intended as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
include/asm-generic/atomic64.h | 3 ++-
lib/atomic64.c | 13 ++++++-------
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h
index e9a94b7a4d0a..b0aa425361ad 100644
--- a/include/asm-generic/atomic64.h
+++ b/include/asm-generic/atomic64.h
@@ -52,7 +52,8 @@ ATOMIC64_OPS(xor)
extern long long atomic64_dec_if_positive(atomic64_t *v);
extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
extern long long atomic64_xchg(atomic64_t *v, long long new);
-extern int atomic64_add_unless(atomic64_t *v, long long a, long long u);
+extern long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u);
+#define atomic64_fetch_add_unless atomic64_fetch_add_unless

#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
#define atomic64_inc(v) atomic64_add(1LL, (v))
diff --git a/lib/atomic64.c b/lib/atomic64.c
index 53c2d5edc826..fb2a38af5ae8 100644
--- a/lib/atomic64.c
+++ b/lib/atomic64.c
@@ -178,18 +178,17 @@ long long atomic64_xchg(atomic64_t *v, long long new)
}
EXPORT_SYMBOL(atomic64_xchg);

-int atomic64_add_unless(atomic64_t *v, long long a, long long u)
+long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- int ret = 0;
+ long long val;

raw_spin_lock_irqsave(lock, flags);
- if (v->counter != u) {
+ val = v->counter;
+ if (val != u)
v->counter += a;
- ret = 1;
- }
raw_spin_unlock_irqrestore(lock, flags);
- return ret;
+ return val;
}
-EXPORT_SYMBOL(atomic64_add_unless);
+EXPORT_SYMBOL(atomic64_fetch_add_unless);
--
2.11.0
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