Cleanup: remove unused value warning

[urcu.git] / urcu / compiler.h

diff --git a/urcu/compiler.h b/urcu/compiler.h
index aab2c5cdd7bff1c590896f0add675ba3435fcc3a..64d12d344a26a1fdca56fd0b1201437241b9967a 100644 (file)
--- a/urcu/compiler.h
+++ b/urcu/compiler.h
@@ -6,7 +6,7 @@
  *
  * Compiler definitions.
  *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
@@ -23,21 +23,21 @@
 #define likely(x)      __builtin_expect(!!(x), 1)
 #define unlikely(x)    __builtin_expect(!!(x), 0)
 
-#define        barrier()       asm volatile("" : : : "memory")
+#define        cmm_barrier()   asm volatile("" : : : "memory")
 
 /*
  * Instruct the compiler to perform only a single access to a variable
  * (prohibits merging and refetching). The compiler is also forbidden to reorder
- * successive instances of ACCESS_ONCE(), but only when the compiler is aware of
+ * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of
  * particular ordering. Compiler ordering can be ensured, for example, by
- * putting two ACCESS_ONCE() in separate C statements.
+ * putting two CMM_ACCESS_ONCE() in separate C statements.
  *
  * This macro does absolutely -nothing- to prevent the CPU from reordering,
  * merging, or refetching absolutely anything at any time.  Its main intended
  * use is to mediate communication between process-level code and irq/NMI
  * handlers, all running on the same CPU.
  */
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&x)
+#define CMM_ACCESS_ONCE(x)     (*(volatile typeof(x) *)&(x))
 
 #ifndef max
 #define max(a,b) ((a)>(b)?(a):(b))
@@ -47,4 +47,18 @@
 #define min(a,b) ((a)<(b)?(a):(b))
 #endif
 
+#if defined(__SIZEOF_LONG__)
+#define CAA_BITS_PER_LONG      (__SIZEOF_LONG__ * 8)
+#elif defined(_LP64)
+#define CAA_BITS_PER_LONG      64
+#else
+#define CAA_BITS_PER_LONG      32
+#endif
+
+#define caa_container_of(ptr, type, member)                                    \
+       ({                                                              \
+               const typeof(((type *)NULL)->member) * __ptr = (ptr);   \
+               (type *)((char *)__ptr - offsetof(type, member));       \
+       })
+
 #endif /* _URCU_COMPILER_H */