1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 301de78d65f7..6c502cb13c95 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -548,6 +548,27 @@ static inline int atomic_dec_if_positive(atomic_t *v)
 }
 #endif
 
+/**
+ * fetch_or - perform *ptr |= mask and return old value of *ptr
+ * @ptr: pointer to value
+ * @mask: mask to OR on the value
+ *
+ * cmpxchg based fetch_or, macro so it works for different integer types
+ */
+#ifndef fetch_or
+#define fetch_or(ptr, mask)                                             \
+({      typeof(*(ptr)) __old, __val = *(ptr);                           \
+        for (;;) {                                                      \
+                __old = cmpxchg((ptr), __val, __val | (mask));          \
+                if (__old == __val)                                     \
+                        break;                                          \
+                __val = __old;                                          \
+        }                                                               \
+        __old;                                                          \
+})
+#endif
+
+
 #ifdef CONFIG_GENERIC_ATOMIC64
 #include <asm-generic/atomic64.h>
 #endif