1 /* 2 * Copyright 2008-2009, Ingo Weinhold, ingo_weinhold@gmx.de. 3 * Copyright 2002-2009, Axel Dörfler, axeld@pinc-software.de. 4 * Distributed under the terms of the MIT License. 5 * 6 * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved. 7 * Distributed under the terms of the NewOS License. 8 */ 9 #ifndef _KERNEL_LOCK_H 10 #define _KERNEL_LOCK_H 11 12 #include <OS.h> 13 #include <debug.h> 14 15 16 struct mutex_waiter; 17 18 typedef struct mutex { 19 const char* name; 20 struct mutex_waiter* waiters; 21 #if KDEBUG 22 thread_id holder; 23 #else 24 int32 count; 25 uint16 ignore_unlock_count; 26 #endif 27 uint8 flags; 28 } mutex; 29 30 #define MUTEX_FLAG_CLONE_NAME 0x1 31 32 33 typedef struct recursive_lock { 34 mutex lock; 35 #if !KDEBUG 36 thread_id holder; 37 #endif 38 int recursion; 39 } recursive_lock; 40 41 42 struct rw_lock_waiter; 43 44 typedef struct rw_lock { 45 const char* name; 46 struct rw_lock_waiter* waiters; 47 thread_id holder; 48 vint32 count; 49 int32 owner_count; 50 int16 active_readers; 51 // Only > 0 while a writer is waiting: number 52 // of active readers when the first waiting 53 // writer started waiting. 54 int16 pending_readers; 55 // Number of readers that have already 56 // incremented "count", but have not yet started 57 // to wait at the time the last writer unlocked. 58 uint32 flags; 59 } rw_lock; 60 61 #define RW_LOCK_WRITER_COUNT_BASE 0x10000 62 63 #define RW_LOCK_FLAG_CLONE_NAME 0x1 64 65 66 #if KDEBUG 67 # define KDEBUG_RW_LOCK_DEBUG 0 68 // Define to 1 if you want to use ASSERT_READ_LOCKED_RW_LOCK(). 69 // The rw_lock will just behave like a recursive locker then. 70 # define ASSERT_LOCKED_RECURSIVE(r) \ 71 { ASSERT(find_thread(NULL) == (r)->lock.holder); } 72 # define ASSERT_LOCKED_MUTEX(m) { ASSERT(find_thread(NULL) == (m)->holder); } 73 # define ASSERT_WRITE_LOCKED_RW_LOCK(l) \ 74 { ASSERT(find_thread(NULL) == (l)->holder); } 75 # if KDEBUG_RW_LOCK_DEBUG 76 # define ASSERT_READ_LOCKED_RW_LOCK(l) \ 77 { ASSERT(find_thread(NULL) == (l)->holder); } 78 # else 79 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 80 # endif 81 #else 82 # define ASSERT_LOCKED_RECURSIVE(r) do {} while (false) 83 # define ASSERT_LOCKED_MUTEX(m) do {} while (false) 84 # define ASSERT_WRITE_LOCKED_RW_LOCK(m) do {} while (false) 85 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 86 #endif 87 88 89 // static initializers 90 #if KDEBUG 91 # define MUTEX_INITIALIZER(name) { name, NULL, -1, 0 } 92 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), 0 } 93 #else 94 # define MUTEX_INITIALIZER(name) { name, NULL, 0, 0, 0 } 95 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), -1, 0 } 96 #endif 97 98 #define RW_LOCK_INITIALIZER(name) { name, NULL, -1, 0, 0, 0 } 99 100 101 #if KDEBUG 102 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->lock.holder) 103 #else 104 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->holder) 105 #endif 106 107 108 #ifdef __cplusplus 109 extern "C" { 110 #endif 111 112 extern void recursive_lock_init(recursive_lock *lock, const char *name); 113 // name is *not* cloned nor freed in recursive_lock_destroy() 114 extern void recursive_lock_init_etc(recursive_lock *lock, const char *name, 115 uint32 flags); 116 extern void recursive_lock_destroy(recursive_lock *lock); 117 extern status_t recursive_lock_lock(recursive_lock *lock); 118 extern status_t recursive_lock_trylock(recursive_lock *lock); 119 extern void recursive_lock_unlock(recursive_lock *lock); 120 extern int32 recursive_lock_get_recursion(recursive_lock *lock); 121 122 extern void rw_lock_init(rw_lock* lock, const char* name); 123 // name is *not* cloned nor freed in rw_lock_destroy() 124 extern void rw_lock_init_etc(rw_lock* lock, const char* name, uint32 flags); 125 extern void rw_lock_destroy(rw_lock* lock); 126 extern status_t rw_lock_write_lock(rw_lock* lock); 127 128 extern void mutex_init(mutex* lock, const char* name); 129 // name is *not* cloned nor freed in mutex_destroy() 130 extern void mutex_init_etc(mutex* lock, const char* name, uint32 flags); 131 extern void mutex_destroy(mutex* lock); 132 extern status_t mutex_switch_lock(mutex* from, mutex* to); 133 // Unlocks "from" and locks "to" such that unlocking and starting to wait 134 // for the lock is atomically. I.e. if "from" guards the object "to" belongs 135 // to, the operation is safe as long as "from" is held while destroying 136 // "to". 137 extern status_t mutex_switch_from_read_lock(rw_lock* from, mutex* to); 138 // Like mutex_switch_lock(), just for a switching from a read-locked 139 // rw_lock. 140 141 142 // implementation private: 143 144 extern status_t _rw_lock_read_lock(rw_lock* lock); 145 extern void _rw_lock_read_unlock(rw_lock* lock, bool threadsLocked); 146 extern void _rw_lock_write_unlock(rw_lock* lock, bool threadsLocked); 147 148 extern status_t _mutex_lock(mutex* lock, bool threadsLocked); 149 extern void _mutex_unlock(mutex* lock, bool threadsLocked); 150 extern status_t _mutex_trylock(mutex* lock); 151 extern status_t _mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, 152 bigtime_t timeout); 153 154 155 static inline status_t 156 rw_lock_read_lock(rw_lock* lock) 157 { 158 #if KDEBUG_RW_LOCK_DEBUG 159 return rw_lock_write_lock(lock); 160 #else 161 int32 oldCount = atomic_add(&lock->count, 1); 162 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 163 return _rw_lock_read_lock(lock); 164 return B_OK; 165 #endif 166 } 167 168 169 static inline void 170 rw_lock_read_unlock(rw_lock* lock) 171 { 172 #if KDEBUG_RW_LOCK_DEBUG 173 rw_lock_write_unlock(lock); 174 #else 175 int32 oldCount = atomic_add(&lock->count, -1); 176 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 177 _rw_lock_read_unlock(lock, false); 178 #endif 179 } 180 181 182 static inline void 183 rw_lock_write_unlock(rw_lock* lock) 184 { 185 _rw_lock_write_unlock(lock, false); 186 } 187 188 189 static inline status_t 190 mutex_lock(mutex* lock) 191 { 192 #if KDEBUG 193 return _mutex_lock(lock, false); 194 #else 195 if (atomic_add(&lock->count, -1) < 0) 196 return _mutex_lock(lock, false); 197 return B_OK; 198 #endif 199 } 200 201 202 static inline status_t 203 mutex_lock_threads_locked(mutex* lock) 204 { 205 #if KDEBUG 206 return _mutex_lock(lock, true); 207 #else 208 if (atomic_add(&lock->count, -1) < 0) 209 return _mutex_lock(lock, true); 210 return B_OK; 211 #endif 212 } 213 214 215 static inline status_t 216 mutex_trylock(mutex* lock) 217 { 218 #if KDEBUG 219 return _mutex_trylock(lock); 220 #else 221 if (atomic_test_and_set(&lock->count, -1, 0) != 0) 222 return B_WOULD_BLOCK; 223 return B_OK; 224 #endif 225 } 226 227 228 static inline status_t 229 mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, bigtime_t timeout) 230 { 231 #if KDEBUG 232 return _mutex_lock_with_timeout(lock, timeoutFlags, timeout); 233 #else 234 if (atomic_add(&lock->count, -1) < 0) 235 return _mutex_lock_with_timeout(lock, timeoutFlags, timeout); 236 return B_OK; 237 #endif 238 } 239 240 241 static inline void 242 mutex_unlock(mutex* lock) 243 { 244 #if !KDEBUG 245 if (atomic_add(&lock->count, 1) < -1) 246 #endif 247 _mutex_unlock(lock, false); 248 } 249 250 251 static inline void 252 mutex_transfer_lock(mutex* lock, thread_id thread) 253 { 254 #if KDEBUG 255 lock->holder = thread; 256 #endif 257 } 258 259 260 extern void lock_debug_init(); 261 262 #ifdef __cplusplus 263 } 264 #endif 265 266 #endif /* _KERNEL_LOCK_H */ 267