urcu-bp: New "bulletproof" RCU library flavor

[userspace-rcu.git] / urcu-bp.h

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+#ifndef _URCU_BP_H
+#define _URCU_BP_H
+
+/*
+ * urcu-bp.h
+ *
+ * Userspace RCU header, "bulletproof" version.
+ *
+ * Slower RCU read-side adapted for tracing library. Does not require thread
+ * registration nor unregistration. Also signal-safe.
+ *
+ * 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>
+
+/*
+ * See urcu-pointer.h and urcu-pointer-static.h for pointer publication headers.
+ */
+#include <urcu-pointer.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.
+ */
+
+#ifdef _LGPL_SOURCE
+
+#include <urcu-bp-static.h>
+
+/*
+ * Mappings for static use of the userspace RCU library.
+ * Should only be used in LGPL-compatible code.
+ */
+
+/*
+ * rcu_read_lock()
+ * rcu_read_unlock()
+ *
+ * Mark the beginning and end of a read-side critical section.
+ */
+#define rcu_read_lock()                _rcu_read_lock()
+#define rcu_read_unlock()      _rcu_read_unlock()
+
+#else /* !_LGPL_SOURCE */
+
+/*
+ * library wrappers to be used by non-LGPL compatible source code.
+ * See LGPL-only urcu-pointer-static.h for documentation.
+ */
+
+extern void rcu_read_lock(void);
+extern void rcu_read_unlock(void);
+
+#endif /* !_LGPL_SOURCE */
+
+extern void synchronize_rcu(void);
+
+/*
+ * In the bulletproof version, the following functions are no-ops.
+ */
+static inline void rcu_register_thread(void)
+{
+}
+
+static inline void rcu_unregister_thread(void)
+{
+}
+
+static inline void urcu_init(void)
+{
+}
+
+#endif /* _URCU_BP_H */