add rcu_cmpxchg_pointer

[urcu.git] / urcu.h

diff --git a/urcu.h b/urcu.h
index d417f34b52ddd1ce1509835dd0b7f062436d96f2..5d92aa7232d4d0b53d262115fefc470d14286af0 100644 (file)
--- a/urcu.h
+++ b/urcu.h
@@ -1,69 +1,100 @@
 #ifndef _URCU_H
 #define _URCU_H
 
-/* The "volatile" is due to gcc bugs */
-#define barrier() __asm__ __volatile__("": : :"memory")
-
-/* x86 32/64 specific */
-#define mb()    asm volatile("mfence":::"memory")
-#define rmb()   asm volatile("lfence":::"memory")
-#define wmb()   asm volatile("sfence" ::: "memory")
+/*
+ * urcu.h
+ *
+ * Userspace RCU header
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * LGPL-compatible code should include this header with :
+ *
+ * #define _LGPL_SOURCE
+ * #include <urcu.h>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
 
+#include <stdlib.h>
+#include <pthread.h>
 
+/*
+ * Important !
+ *
+ * Each thread containing read-side critical sections must be registered
+ * with rcu_register_thread() before calling rcu_read_lock().
+ * rcu_unregister_thread() should be called before the thread exits.
+ */
 
-/* x86 32 */
-static inline void atomic_inc(int *v)
-{
-       asm volatile("lock; incl %0"
-                    : "+m" (v->counter));
-}
+#ifdef _LGPL_SOURCE
 
-/* Nop everywhere except on alpha. */
-#define smp_read_barrier_depends()
+#include <urcu-static.h>
 
-#define SIGURCU SIGUSR1
+/*
+ * Mappings for static use of the userspace RCU library.
+ * Should only be used in LGPL-compatible code.
+ */
 
-/* Global quiescent period parity */
-extern int urcu_qparity;
+#define rcu_dereference                _rcu_dereference
+#define rcu_read_lock          _rcu_read_lock
+#define rcu_read_unlock                _rcu_read_unlock
 
-extern int __thread urcu_active_readers[2];
+#define rcu_assign_pointer     _rcu_assign_pointer
+#define rcu_xchg_pointer       _rcu_xchg_pointer
+#define rcu_publish_content    _rcu_publish_content
 
-static inline int get_urcu_qparity(void)
-{
-       return urcu_qparity;
-}
+#else /* !_LGPL_SOURCE */
 
 /*
- * returns urcu_parity.
+ * library wrappers to be used by non-LGPL compatible source code.
  */
-static inline int rcu_read_lock(void)
-{
-       int urcu_parity = get_urcu_qparity();
-       urcu_active_readers[urcu_parity]++;
-       /*
-        * Increment active readers count before accessing the pointer.
-        * See force_mb_all_threads().
-        */
-       barrier();
-       return urcu_parity;
-}
-
-static inline void rcu_read_unlock(int urcu_parity)
-{
-       barrier();
-       /*
-        * Finish using rcu before decrementing the pointer.
-        * See force_mb_all_threads().
-        */
-       urcu_active_readers[urcu_parity]--;
-}
-
-extern void *urcu_publish_content(void **ptr, void *new);
+
+extern void rcu_read_lock(void);
+extern void rcu_read_unlock(void);
+
+extern void *rcu_dereference(void *p);
+
+extern void *rcu_assign_pointer_sym(void **p, void *v);
+
+#define rcu_assign_pointer(p, v)                       \
+       rcu_assign_pointer_sym((void **)(p), (v))
+
+extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
+#define rcu_cmpxchg_pointer(p, old, _new)              \
+       rcu_cmpxchg_pointer_sym((void **)(p), (old), (_new))
+
+extern void *rcu_xchg_pointer_sym(void **p, void *v);
+#define rcu_xchg_pointer(p, v)                         \
+       rcu_xchg_pointer_sym((void **)(p), (v))
+
+extern void *rcu_publish_content_sym(void **p, void *v);
+#define rcu_publish_content(p, v)                      \
+       rcu_publish_content_sym((void **)(p), (v))
+
+#endif /* !_LGPL_SOURCE */
+
+extern void synchronize_rcu(void);
 
 /*
  * Reader thread registration.
  */
-extern void urcu_register_thread(void);
-extern void urcu_register_thread(void);
+extern void rcu_register_thread(void);
+extern void rcu_unregister_thread(void);
 
 #endif /* _URCU_H */