diff options
Diffstat (limited to 'xf86atomic.h')
| -rw-r--r-- | xf86atomic.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/xf86atomic.h b/xf86atomic.h index db2f6195..bc482c92 100644 --- a/xf86atomic.h +++ b/xf86atomic.h @@ -96,4 +96,13 @@ typedef struct { uint_t atomic; } atomic_t; #error libdrm requires atomic operations, please define them for your CPU/compiler. #endif +static inline int atomic_add_unless(atomic_t *v, int add, int unless) +{ + int c, old; + c = atomic_read(v); + while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c) + c = old; + return c == unless; +} + #endif |