s390/atomic: Implement arch_atomic_inc() / arch_atomic_dec()

Implement arch_atomic_inc() / arch_atomic_dec() functions which result
in a single instruction if compiled for z196 or newer architectures.

Reduces the kernel image size by ~6K (defconfig):

bloat-o-meter:
add/remove: 0/0 grow/shrink: 12/1005 up/down: 106/-6404 (-6298)

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h
index 6723fca640182118943a53b1b8676d2f463c15ba..c1a4a06e83408947016387c384c755df0f1a70c9 100644 (file)
--- a/arch/s390/include/asm/atomic.h
+++ b/arch/s390/include/asm/atomic.h
@@ -45,6 +45,18 @@ static __always_inline void arch_atomic_add(int i, atomic_t *v)
 }
 #define arch_atomic_add arch_atomic_add
 
+static __always_inline void arch_atomic_inc(atomic_t *v)
+{
+       __atomic_add_const(1, &v->counter);
+}
+#define arch_atomic_inc arch_atomic_inc
+
+static __always_inline void arch_atomic_dec(atomic_t *v)
+{
+       __atomic_add_const(-1, &v->counter);
+}
+#define arch_atomic_dec arch_atomic_dec
+
 #define arch_atomic_sub(_i, _v)                arch_atomic_add(-(int)(_i), _v)
 #define arch_atomic_sub_return(_i, _v) arch_atomic_add_return(-(int)(_i), _v)
 #define arch_atomic_fetch_sub(_i, _v)  arch_atomic_fetch_add(-(int)(_i), _v)
@@ -122,6 +134,18 @@ static __always_inline void arch_atomic64_add(s64 i, atomic64_t *v)
 }
 #define arch_atomic64_add arch_atomic64_add
 
+static __always_inline void arch_atomic64_inc(atomic64_t *v)
+{
+       __atomic64_add_const(1, (long *)&v->counter);
+}
+#define arch_atomic64_inc arch_atomic64_inc
+
+static __always_inline void arch_atomic64_dec(atomic64_t *v)
+{
+       __atomic64_add_const(-1, (long *)&v->counter);
+}
+#define arch_atomic64_dec arch_atomic64_dec
+
 static __always_inline s64 arch_atomic64_xchg(atomic64_t *v, s64 new)
 {
        return arch_xchg(&v->counter, new);