[Qemu-devel] [PATCH v3 01/12] atomic: introduce atomic_dec_fetch.

[Sergey Fedorov <sergey.fedorov@linaro.org>]

From: Alex Bennée <alex.bennee@linaro.org>

Useful for counting down.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
---
 include/qemu/atomic.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index 7a590969b59f..8ac9ca7f457a 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -162,6 +162,8 @@
 #define atomic_fetch_and(ptr, n) __atomic_fetch_and(ptr, n, __ATOMIC_SEQ_CST)
 #define atomic_fetch_or(ptr, n)  __atomic_fetch_or(ptr, n, __ATOMIC_SEQ_CST)
 
+#define atomic_dec_fetch(ptr)  __atomic_sub_fetch(ptr, 1, __ATOMIC_SEQ_CST)
+
 /* And even shorter names that return void.  */
 #define atomic_inc(ptr)    ((void) __atomic_fetch_add(ptr, 1, __ATOMIC_SEQ_CST))
 #define atomic_dec(ptr)    ((void) __atomic_fetch_sub(ptr, 1, __ATOMIC_SEQ_CST))
@@ -357,6 +359,8 @@
 #define atomic_fetch_or        __sync_fetch_and_or
 #define atomic_cmpxchg         __sync_val_compare_and_swap
 
+#define atomic_dec_fetch(ptr)  __sync_sub_and_fetch(ptr, 1)
+
 /* And even shorter names that return void.  */
 #define atomic_inc(ptr)        ((void) __sync_fetch_and_add(ptr, 1))
 #define atomic_dec(ptr)        ((void) __sync_fetch_and_add(ptr, -1))
-- 
1.9.1