+++ /dev/null
-#ifndef _URCU_POINTER_STATIC_H
-#define _URCU_POINTER_STATIC_H
-
-/*
- * urcu-pointer-static.h
- *
- * Userspace RCU header. Operations on pointers.
- *
- * 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.
- *
- * 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 <urcu/compiler.h>
-#include <urcu/arch.h>
-#include <urcu/system.h>
-#include <urcu/uatomic.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/**
- * _rcu_dereference - reads (copy) a RCU-protected pointer to a local variable
- * into a RCU read-side critical section. The pointer can later be safely
- * dereferenced within the critical section.
- *
- * This ensures that the pointer copy is invariant thorough the whole critical
- * section.
- *
- * Inserts memory barriers on architectures that require them (currently only
- * Alpha) and documents which pointers are protected by RCU.
- *
- * The compiler memory barrier in CMM_LOAD_SHARED() ensures that value-speculative
- * optimizations (e.g. VSS: Value Speculation Scheduling) does not perform the
- * data read before the pointer read by speculating the value of the pointer.
- * Correct ordering is ensured because the pointer is read as a volatile access.
- * This acts as a global side-effect operation, which forbids reordering of
- * dependent memory operations. Note that such concern about dependency-breaking
- * optimizations will eventually be taken care of by the "memory_order_consume"
- * 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) \
- __extension__ \
- ({ \
- __typeof__(p) _________p1 = CMM_LOAD_SHARED(p); \
- cmm_smp_read_barrier_depends(); \
- (_________p1); \
- })
-
-/**
- * _rcu_cmpxchg_pointer - same as rcu_assign_pointer, but tests if the pointer
- * is as expected by "old". If succeeds, returns the previous pointer to the
- * 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); \
- if (!__builtin_constant_p(_new) || \
- ((_new) != NULL)) \
- cmm_wmb(); \
- uatomic_cmpxchg(p, _________pold, _________pnew); \
- })
-
-/**
- * _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); \
- if (!__builtin_constant_p(v) || \
- ((v) != NULL)) \
- cmm_wmb(); \
- uatomic_xchg(p, _________pv); \
- })
-
-
-#define _rcu_set_pointer(p, 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
- * meant to be read by RCU read-side critical sections. Returns the assigned
- * value.
- *
- * Documents which pointers will be dereferenced by RCU read-side critical
- * sections and adds the required memory barriers on architectures requiring
- * them. It also makes sure the compiler does not reorder code initializing the
- * data structure before its publication.
- *
- * 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
-}
-#endif
-
-#endif /* _URCU_POINTER_STATIC_H */
projects / urcu.git / blobdiff