*
* Userspace RCU header. Operations on pointers.
*
- * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu-pointer.h for
- * linking dynamically with the userspace rcu library.
+ * TO BE INCLUDED ONLY IN CODE THAT IS TO BE RECOMPILED ON EACH LIBURCU
+ * RELEASE. See urcu.h for linking dynamically with the userspace rcu library.
*
* Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
* Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
#ifdef __cplusplus
extern "C" {
-#endif
+#endif
/**
* _rcu_dereference - reads (copy) a RCU-protected pointer to a local variable
* addition to forthcoming C++ standard.
*
* Should match rcu_assign_pointer() or rcu_xchg_pointer().
+ *
+ * This macro is less than 10 lines long. The intent is that this macro
+ * meets the 10-line criterion in LGPL, allowing this function to be
+ * expanded directly in non-LGPL code.
*/
-
-#define _rcu_dereference(p) ({ \
- typeof(p) _________p1 = CMM_LOAD_SHARED(p); \
+#define _rcu_dereference(p) \
+ __extension__ \
+ ({ \
+ __typeof__(p) _________p1 = CMM_LOAD_SHARED(p); \
cmm_smp_read_barrier_depends(); \
(_________p1); \
})
* data structure, which can be safely freed after waiting for a quiescent state
* using synchronize_rcu(). If fails (unexpected value), returns old (which
* should not be freed !).
+ *
+ * This macro is less than 10 lines long. The intent is that this macro
+ * meets the 10-line criterion in LGPL, allowing this function to be
+ * expanded directly in non-LGPL code.
*/
-
#define _rcu_cmpxchg_pointer(p, old, _new) \
+ __extension__ \
({ \
- typeof(*p) _________pold = (old); \
- typeof(*p) _________pnew = (_new); \
+ __typeof__(*p) _________pold = (old); \
+ __typeof__(*p) _________pnew = (_new); \
if (!__builtin_constant_p(_new) || \
((_new) != NULL)) \
cmm_wmb(); \
* _rcu_xchg_pointer - same as rcu_assign_pointer, but returns the previous
* pointer to the data structure, which can be safely freed after waiting for a
* quiescent state using synchronize_rcu().
+ *
+ * This macro is less than 10 lines long. The intent is that this macro
+ * meets the 10-line criterion in LGPL, allowing this function to be
+ * expanded directly in non-LGPL code.
*/
-
#define _rcu_xchg_pointer(p, v) \
+ __extension__ \
({ \
- typeof(*p) _________pv = (v); \
+ __typeof__(*p) _________pv = (v); \
if (!__builtin_constant_p(v) || \
((v) != NULL)) \
cmm_wmb(); \
#define _rcu_set_pointer(p, v) \
- ({ \
- typeof(*p) _________pv = (v); \
+ do { \
+ __typeof__(*p) _________pv = (v); \
if (!__builtin_constant_p(v) || \
((v) != NULL)) \
cmm_wmb(); \
uatomic_set(p, _________pv); \
- })
+ } while (0)
/**
* _rcu_assign_pointer - assign (publicize) a pointer to a new data structure
* them. It also makes sure the compiler does not reorder code initializing the
* data structure before its publication.
*
- * Should match rcu_dereference_pointer().
+ * Should match rcu_dereference().
+ *
+ * This macro is less than 10 lines long. The intent is that this macro
+ * meets the 10-line criterion in LGPL, allowing this function to be
+ * expanded directly in non-LGPL code.
*/
-
#define _rcu_assign_pointer(p, v) _rcu_set_pointer(&(p), v)
-#ifdef __cplusplus
+#ifdef __cplusplus
}
#endif