| 1 | #ifndef _URCU_QSBR_H |
| 2 | #define _URCU_QSBR_H |
| 3 | |
| 4 | /* |
| 5 | * urcu-qsbr.h |
| 6 | * |
| 7 | * Userspace RCU QSBR header. |
| 8 | * |
| 9 | * LGPL-compatible code should include this header with : |
| 10 | * |
| 11 | * #define _LGPL_SOURCE |
| 12 | * #include <urcu.h> |
| 13 | * |
| 14 | * This library is free software; you can redistribute it and/or |
| 15 | * modify it under the terms of the GNU Lesser General Public |
| 16 | * License as published by the Free Software Foundation; either |
| 17 | * version 2.1 of the License, or (at your option) any later version. |
| 18 | * |
| 19 | * This library is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 22 | * Lesser General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Lesser General Public |
| 25 | * License along with this library; if not, write to the Free Software |
| 26 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 27 | * |
| 28 | * IBM's contributions to this file may be relicensed under LGPLv2 or later. |
| 29 | */ |
| 30 | |
| 31 | #include <stdlib.h> |
| 32 | #include <pthread.h> |
| 33 | |
| 34 | /* |
| 35 | * Important ! |
| 36 | * |
| 37 | * Each thread containing read-side critical sections must be registered |
| 38 | * with rcu_register_thread() before calling rcu_read_lock(). |
| 39 | * rcu_unregister_thread() should be called before the thread exits. |
| 40 | */ |
| 41 | |
| 42 | #ifdef _LGPL_SOURCE |
| 43 | |
| 44 | #include <urcu-qsbr-static.h> |
| 45 | |
| 46 | /* |
| 47 | * Mappings for static use of the userspace RCU library. |
| 48 | * Should only be used in LGPL-compatible code. |
| 49 | */ |
| 50 | |
| 51 | #define rcu_dereference _rcu_dereference |
| 52 | #define rcu_read_lock _rcu_read_lock |
| 53 | #define rcu_read_unlock _rcu_read_unlock |
| 54 | |
| 55 | #define rcu_quiescent_state _rcu_quiescent_state |
| 56 | #define rcu_thread_offline _rcu_thread_offline |
| 57 | #define rcu_thread_online _rcu_thread_online |
| 58 | |
| 59 | #define rcu_assign_pointer _rcu_assign_pointer |
| 60 | #define rcu_cmpxchg_pointer _rcu_cmpxchg_pointer |
| 61 | #define rcu_xchg_pointer _rcu_xchg_pointer |
| 62 | #define rcu_publish_content _rcu_publish_content |
| 63 | |
| 64 | #else /* !_LGPL_SOURCE */ |
| 65 | |
| 66 | /* |
| 67 | * library wrappers to be used by non-LGPL compatible source code. |
| 68 | */ |
| 69 | |
| 70 | /* |
| 71 | * QSBR read lock/unlock are guaranteed to be no-ops. Therefore, we expose them |
| 72 | * in the LGPL header for any code to use. However, the debug version is not |
| 73 | * nops and may contain sanity checks. To activate it, applications must be |
| 74 | * recompiled with -DURCU_DEBUG (even non-LGPL/GPL applications). This is the |
| 75 | * best trade-off between license/performance/code triviality and |
| 76 | * library debugging & tracing features we could come up with. |
| 77 | */ |
| 78 | |
| 79 | #if (!defined(BUILD_QSBR_LIB) && defined(URCU_DEBUG)) |
| 80 | |
| 81 | static inline void rcu_read_lock(void) |
| 82 | { |
| 83 | } |
| 84 | |
| 85 | static inline void rcu_read_lock(void) |
| 86 | { |
| 87 | } |
| 88 | |
| 89 | #else /* !URCU_DEBUG */ |
| 90 | |
| 91 | extern void rcu_read_lock(void); |
| 92 | extern void rcu_read_unlock(void); |
| 93 | |
| 94 | #endif /* !URCU_DEBUG */ |
| 95 | |
| 96 | extern void *rcu_dereference(void *p); |
| 97 | |
| 98 | extern void rcu_quiescent_state(void); |
| 99 | extern void rcu_thread_offline(void); |
| 100 | extern void rcu_thread_online(void); |
| 101 | |
| 102 | extern void *rcu_assign_pointer_sym(void **p, void *v); |
| 103 | |
| 104 | #define rcu_assign_pointer(p, v) \ |
| 105 | rcu_assign_pointer_sym((void **)(p), (v)) |
| 106 | |
| 107 | extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new); |
| 108 | #define rcu_cmpxchg_pointer(p, old, _new) \ |
| 109 | rcu_cmpxchg_pointer_sym((void **)(p), (old), (_new)) |
| 110 | |
| 111 | extern void *rcu_xchg_pointer_sym(void **p, void *v); |
| 112 | #define rcu_xchg_pointer(p, v) \ |
| 113 | rcu_xchg_pointer_sym((void **)(p), (v)) |
| 114 | |
| 115 | extern void *rcu_publish_content_sym(void **p, void *v); |
| 116 | #define rcu_publish_content(p, v) \ |
| 117 | rcu_publish_content_sym((void **)(p), (v)) |
| 118 | |
| 119 | #endif /* !_LGPL_SOURCE */ |
| 120 | |
| 121 | extern void synchronize_rcu(void); |
| 122 | |
| 123 | /* |
| 124 | * Reader thread registration. |
| 125 | */ |
| 126 | extern void rcu_register_thread(void); |
| 127 | extern void rcu_unregister_thread(void); |
| 128 | |
| 129 | #endif /* _URCU_QSBR_H */ |