urcu-pointer.c

   1
   2 /*
   3  * urcu-pointer.c
   4  *
   5  * library wrappers to be used by non-LGPL compatible source code.
   6  *
   7  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   8  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  *
  24  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  25  */
  26
  27 #include "urcu-pointer-static.h"
  28 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
  29 #include "urcu-pointer.h"
  30
  31 extern void synchronize_rcu(void);
  32
  33 void *rcu_dereference_sym(void *p)
  34 {
  35         return _rcu_dereference(p);
  36 }
  37
  38 void *rcu_set_pointer_sym(void **p, void *v)
  39 {
  40         wmb();
  41         return STORE_SHARED(*p, v);
  42 }
  43
  44 void *rcu_xchg_pointer_sym(void **p, void *v)
  45 {
  46         wmb();
  47         return uatomic_xchg(p, v);
  48 }
  49
  50 void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new)
  51 {
  52         wmb();
  53         if (likely(URCU_CAS_AVAIL()))
  54                 return uatomic_cmpxchg(p, old, _new);
  55
  56         /* Compatibility for i386. Old-timer. */
  57         return compat_uatomic_cmpxchg(p, old, _new);
  58 }