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

#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

#if defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)

#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 /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */

extern void *rcu_dereference_sym(void *p);
#define rcu_dereference(p)						     \
	__extension__							     \
	({								     \
		__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)				     \
	__extension__							     \
	({								     \
		__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)						     \
	__extension__							     \
	({								     \
		__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 /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */

/*
 * 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 */
Commit	Line	Data
	1	#ifndef _URCU_POINTER_H
	2	#define _URCU_POINTER_H
	3
	4	/*
	5	* urcu-pointer.h
	6	*
	7	* Userspace RCU header. Operations on pointers.
	8	*
	9	* Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	10	* Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
	11	*
	12	* This library is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU Lesser General Public
	14	* License as published by the Free Software Foundation; either
	15	* version 2.1 of the License, or (at your option) any later version.
	16	*
	17	* This library is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	20	* Lesser General Public License for more details.
	21	*
	22	* You should have received a copy of the GNU Lesser General Public
	23	* License along with this library; if not, write to the Free Software
	24	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	25	*
	26	* IBM's contributions to this file may be relicensed under LGPLv2 or later.
	27	*/
	28
	29	#include <urcu/compiler.h>
	30	#include <urcu/arch.h>
	31	#include <urcu/uatomic.h>
	32
	33	#ifdef __cplusplus
	34	extern "C" {
	35	#endif
	36
	37	#if defined(_LGPL_SOURCE) \|\| defined(URCU_INLINE_SMALL_FUNCTIONS)
	38
	39	#include <urcu/static/urcu-pointer.h>
	40
	41	/*
	42	* rcu_dereference(ptr)
	43	*
	44	* Fetch a RCU-protected pointer. Typically used to copy the variable ptr to a
	45	* local variable.
	46	*/
	47	#define rcu_dereference _rcu_dereference
	48
	49	/*
	50	* type rcu_cmpxchg_pointer(type ptr, type new, type *old)
	51	* type rcu_xchg_pointer(type ptr, type new)
	52	* void rcu_set_pointer(type *ptr, type new)
	53	*
	54	* RCU pointer updates.
	55	* @ptr: address of the pointer to modify
	56	* @new: new pointer value
	57	* @old: old pointer value (expected)
	58	*
	59	* return: old pointer value
	60	*/
	61	#define rcu_cmpxchg_pointer _rcu_cmpxchg_pointer
	62	#define rcu_xchg_pointer _rcu_xchg_pointer
	63	#define rcu_set_pointer _rcu_set_pointer
	64
	65	#else /* !(defined(_LGPL_SOURCE) \|\| defined(URCU_INLINE_SMALL_FUNCTIONS)) */
	66
	67	extern void rcu_dereference_sym(void p);
	68	#define rcu_dereference(p) \
	69	__extension__ \
	70	({ \
	71	__typeof__(p) _________p1 = URCU_FORCE_CAST(__typeof__(p), \
	72	rcu_dereference_sym(URCU_FORCE_CAST(void *, p))); \
	73	(_________p1); \
	74	})
	75
	76	extern void rcu_cmpxchg_pointer_sym(void p, void old, void *_new);
	77	#define rcu_cmpxchg_pointer(p, old, _new) \
	78	__extension__ \
	79	({ \
	80	__typeof__(*(p)) _________pold = (old); \
	81	__typeof__(*(p)) _________pnew = (_new); \
	82	__typeof__((p)) _________p1 = URCU_FORCE_CAST(__typeof__((p)), \
	83	rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
	84	_________pold, \
	85	_________pnew)); \
	86	(_________p1); \
	87	})
	88
	89	extern void rcu_xchg_pointer_sym(void p, void v);
	90	#define rcu_xchg_pointer(p, v) \
	91	__extension__ \
	92	({ \
	93	__typeof__(*(p)) _________pv = (v); \
	94	__typeof__((p)) _________p1 = URCU_FORCE_CAST(__typeof__((p)), \
	95	rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
	96	_________pv)); \
	97	(_________p1); \
	98	})
	99
	100	/*
	101	* Note: rcu_set_pointer_sym returns @v because we don't want to break
	102	* the ABI. At the API level, rcu_set_pointer() now returns void. Use of
	103	* the return value is therefore deprecated, and will cause a build
	104	* error.
	105	*/
	106	extern void rcu_set_pointer_sym(void p, void v);
	107	#define rcu_set_pointer(p, v) \
	108	do { \
	109	__typeof__(*(p)) _________pv = (v); \
	110	(void) rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p), \
	111	_________pv); \
	112	} while (0)
	113
	114	#endif /* !(defined(_LGPL_SOURCE) \|\| defined(URCU_INLINE_SMALL_FUNCTIONS)) */
	115
	116	/*
	117	* void rcu_assign_pointer(type ptr, type new)
	118	*
	119	* Same as rcu_set_pointer, but takes the pointer to assign to rather than its
	120	* address as first parameter. Provided for compatibility with the Linux kernel
	121	* RCU semantic.
	122	*/
	123	#define rcu_assign_pointer(p, v) rcu_set_pointer((&p), (v))
	124
	125	#ifdef __cplusplus
	126	}
	127	#endif
	128
	129	#endif /* _URCU_POINTER_H */