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#ifndef _URCU_POINTER_H
#define _URCU_POINTER_H
/*
* urcu-pointer.h
*
* Userspace RCU header. Operations on pointers.
*
* 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/uatomic.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef _LGPL_SOURCE
#include <urcu/static/urcu-pointer.h>
/*
* rcu_dereference(ptr)
*
* Fetch a RCU-protected pointer. Typically used to copy the variable ptr to a
* local variable.
*/
#define rcu_dereference _rcu_dereference
/*
* type *rcu_cmpxchg_pointer(type **ptr, type *new, type *old)
* type *rcu_xchg_pointer(type **ptr, type *new)
* void rcu_set_pointer(type **ptr, type *new)
*
* RCU pointer updates.
* @ptr: address of the pointer to modify
* @new: new pointer value
* @old: old pointer value (expected)
*
* return: old pointer value
*/
#define rcu_cmpxchg_pointer _rcu_cmpxchg_pointer
#define rcu_xchg_pointer _rcu_xchg_pointer
#define rcu_set_pointer _rcu_set_pointer
#else /* !_LGPL_SOURCE */
extern void *rcu_dereference_sym(void *p);
#define rcu_dereference(p) \
({ \
__typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p), \
rcu_dereference_sym(URCU_FORCE_CAST(void *, p))); \
(_________p1); \
})
extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
#define rcu_cmpxchg_pointer(p, old, _new) \
({ \
__typeof__(*(p)) _________pold = (old); \
__typeof__(*(p)) _________pnew = (_new); \
__typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
_________pold, \
_________pnew)); \
(_________p1); \
})
extern void *rcu_xchg_pointer_sym(void **p, void *v);
#define rcu_xchg_pointer(p, v) \
({ \
__typeof__(*(p)) _________pv = (v); \
__typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
_________pv)); \
(_________p1); \
})
/*
* Note: rcu_set_pointer_sym returns @v because we don't want to break
* the ABI. At the API level, rcu_set_pointer() now returns void. Use of
* the return value is therefore deprecated, and will cause a build
* error.
*/
extern void *rcu_set_pointer_sym(void **p, void *v);
#define rcu_set_pointer(p, v) \
do { \
__typeof__(*(p)) _________pv = (v); \
(void) rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p), \
_________pv); \
} while (0)
#endif /* !_LGPL_SOURCE */
/*
* void rcu_assign_pointer(type *ptr, type *new)
*
* Same as rcu_set_pointer, but takes the pointer to assign to rather than its
* address as first parameter. Provided for compatibility with the Linux kernel
* RCU semantic.
*/
#define rcu_assign_pointer(p, v) rcu_set_pointer((&p), (v))
#ifdef __cplusplus
}
#endif
#endif /* _URCU_POINTER_H */
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