[PATCHv3 12/18] atomics/powerpc: define atomic64_fetch_add_unless()

From: Mark Rutland
Date: Mon Jun 18 2018 - 06:20:05 EST


As a step towards unifying the atomic/atomic64/atomic_long APIs, this
patch converts the arch/powerpc implementation of atomic64_add_unless()
into an 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@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
---
arch/powerpc/include/asm/atomic.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
index b5646c079c16..233dbf31911c 100644
--- a/arch/powerpc/include/asm/atomic.h
+++ b/arch/powerpc/include/asm/atomic.h
@@ -525,7 +525,7 @@ static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
#define atomic64_xchg_relaxed(v, new) xchg_relaxed(&((v)->counter), (new))

/**
- * atomic64_add_unless - add unless the number is a given value
+ * atomic64_fetch_add_unless - add unless the number is a given value
* @v: pointer of type atomic64_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
@@ -533,13 +533,13 @@ static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
* Atomically adds @a to @v, so long as it was not @u.
* Returns the old value of @v.
*/
-static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
+static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
{
long t;

__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
-"1: ldarx %0,0,%1 # atomic_fetch_add_unless\n\
+"1: ldarx %0,0,%1 # atomic64_fetch_add_unless\n\
cmpd 0,%0,%3 \n\
beq 2f \n\
add %0,%2,%0 \n"
@@ -552,8 +552,9 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
: "r" (&v->counter), "r" (a), "r" (u)
: "cc", "memory");

- return t != u;
+ return t;
}
+#define atomic64_fetch_add_unless atomic64_fetch_add_unless

/**
* atomic_inc64_not_zero - increment unless the number is zero
--
2.11.0