1 /* 2 * Copyright 2008-2011, 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 13 #include <OS.h> 14 15 #include <arch/atomic.h> 16 #include <debug.h> 17 18 19 struct mutex_waiter; 20 21 typedef struct mutex { 22 const char* name; 23 struct mutex_waiter* waiters; 24 spinlock lock; 25 #if KDEBUG 26 thread_id holder; 27 #else 28 int32 count; 29 #endif 30 uint8 flags; 31 } mutex; 32 33 #define MUTEX_FLAG_CLONE_NAME 0x1 34 35 36 typedef struct recursive_lock { 37 mutex lock; 38 #if !KDEBUG 39 thread_id holder; 40 #else 41 int32 _unused; 42 #endif 43 int recursion; 44 } recursive_lock; 45 46 47 struct rw_lock_waiter; 48 49 typedef struct rw_lock { 50 const char* name; 51 struct rw_lock_waiter* waiters; 52 spinlock lock; 53 thread_id holder; 54 int32 count; 55 int32 owner_count; 56 int16 active_readers; 57 // Only > 0 while a writer is waiting: number 58 // of active readers when the first waiting 59 // writer started waiting. 60 int16 pending_readers; 61 // Number of readers that have already 62 // incremented "count", but have not yet started 63 // to wait at the time the last writer unlocked. 64 uint32 flags; 65 } rw_lock; 66 67 #define RW_LOCK_WRITER_COUNT_BASE 0x10000 68 69 #define RW_LOCK_FLAG_CLONE_NAME 0x1 70 71 72 #if KDEBUG 73 # define KDEBUG_RW_LOCK_DEBUG 0 74 // Define to 1 if you want to use ASSERT_READ_LOCKED_RW_LOCK(). 75 # define ASSERT_LOCKED_RECURSIVE(r) \ 76 { ASSERT(find_thread(NULL) == (r)->lock.holder); } 77 # define ASSERT_LOCKED_MUTEX(m) { ASSERT(find_thread(NULL) == (m)->holder); } 78 # define ASSERT_WRITE_LOCKED_RW_LOCK(l) \ 79 { ASSERT(find_thread(NULL) == (l)->holder); } 80 # if KDEBUG_RW_LOCK_DEBUG 81 extern bool _rw_lock_is_read_locked(rw_lock* lock); 82 # define ASSERT_READ_LOCKED_RW_LOCK(l) \ 83 { ASSERT_PRINT(_rw_lock_is_read_locked(l), "rwlock %p", l); } 84 # define ASSERT_UNLOCKED_RW_LOCK(l) \ 85 { ASSERT_PRINT(!_rw_lock_is_read_locked(l), "rwlock %p", l); } 86 # else 87 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 88 # define ASSERT_UNLOCKED_RW_LOCK(l) do {} while (false) 89 # endif 90 #else 91 # define ASSERT_LOCKED_RECURSIVE(r) do {} while (false) 92 # define ASSERT_LOCKED_MUTEX(m) do {} while (false) 93 # define ASSERT_WRITE_LOCKED_RW_LOCK(m) do {} while (false) 94 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 95 # define ASSERT_UNLOCKED_RW_LOCK(l) do {} while (false) 96 #endif 97 98 99 // static initializers 100 #if KDEBUG 101 # define MUTEX_INITIALIZER(name) \ 102 { name, NULL, B_SPINLOCK_INITIALIZER, -1, 0 } 103 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), 0 } 104 #else 105 # define MUTEX_INITIALIZER(name) \ 106 { name, NULL, B_SPINLOCK_INITIALIZER, 0, 0 } 107 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), -1, 0 } 108 #endif 109 110 #define RW_LOCK_INITIALIZER(name) \ 111 { name, NULL, B_SPINLOCK_INITIALIZER, -1, 0, 0, 0, 0, 0 } 112 113 114 #if KDEBUG 115 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->lock.holder) 116 #else 117 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->holder) 118 #endif 119 120 121 #ifdef __cplusplus 122 extern "C" { 123 #endif 124 125 extern void recursive_lock_init(recursive_lock *lock, const char *name); 126 // name is *not* cloned nor freed in recursive_lock_destroy() 127 extern void recursive_lock_init_etc(recursive_lock *lock, const char *name, 128 uint32 flags); 129 extern void recursive_lock_destroy(recursive_lock *lock); 130 extern status_t recursive_lock_lock(recursive_lock *lock); 131 extern status_t recursive_lock_trylock(recursive_lock *lock); 132 extern void recursive_lock_unlock(recursive_lock *lock); 133 extern status_t recursive_lock_switch_lock(recursive_lock* from, 134 recursive_lock* to); 135 // Unlocks "from" and locks "to" such that unlocking and starting to wait 136 // for the lock is atomic. I.e. if "from" guards the object "to" belongs 137 // to, the operation is safe as long as "from" is held while destroying 138 // "to". 139 extern status_t recursive_lock_switch_from_mutex(mutex* from, 140 recursive_lock* to); 141 // Like recursive_lock_switch_lock(), just for switching from a mutex. 142 extern status_t recursive_lock_switch_from_read_lock(rw_lock* from, 143 recursive_lock* to); 144 // Like recursive_lock_switch_lock(), just for switching from a read-locked 145 // rw_lock. 146 extern int32 recursive_lock_get_recursion(recursive_lock *lock); 147 148 extern void rw_lock_init(rw_lock* lock, const char* name); 149 // name is *not* cloned nor freed in rw_lock_destroy() 150 extern void rw_lock_init_etc(rw_lock* lock, const char* name, uint32 flags); 151 extern void rw_lock_destroy(rw_lock* lock); 152 extern status_t rw_lock_write_lock(rw_lock* lock); 153 154 extern void mutex_init(mutex* lock, const char* name); 155 // name is *not* cloned nor freed in mutex_destroy() 156 extern void mutex_init_etc(mutex* lock, const char* name, uint32 flags); 157 extern void mutex_destroy(mutex* lock); 158 extern void mutex_transfer_lock(mutex* lock, thread_id thread); 159 extern status_t mutex_switch_lock(mutex* from, mutex* to); 160 // Unlocks "from" and locks "to" such that unlocking and starting to wait 161 // for the lock is atomic. I.e. if "from" guards the object "to" belongs 162 // to, the operation is safe as long as "from" is held while destroying 163 // "to". 164 extern status_t mutex_switch_from_read_lock(rw_lock* from, mutex* to); 165 // Like mutex_switch_lock(), just for switching from a read-locked rw_lock. 166 167 #if KDEBUG 168 extern status_t mutex_lock(mutex* lock); 169 extern void mutex_unlock(mutex* lock); 170 extern status_t mutex_trylock(mutex* lock); 171 extern status_t mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, 172 bigtime_t timeout); 173 #endif 174 175 176 // implementation private: 177 178 extern status_t _rw_lock_read_lock(rw_lock* lock); 179 extern status_t _rw_lock_read_lock_with_timeout(rw_lock* lock, 180 uint32 timeoutFlags, bigtime_t timeout); 181 extern void _rw_lock_read_unlock(rw_lock* lock); 182 extern void _rw_lock_write_unlock(rw_lock* lock); 183 184 #if !KDEBUG 185 extern status_t _mutex_lock(mutex* lock, void* locker); 186 extern void _mutex_unlock(mutex* lock); 187 extern status_t _mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, 188 bigtime_t timeout); 189 #endif 190 191 192 static inline status_t 193 rw_lock_read_lock(rw_lock* lock) 194 { 195 #if KDEBUG_RW_LOCK_DEBUG 196 return _rw_lock_read_lock(lock); 197 #else 198 int32 oldCount = atomic_add(&lock->count, 1); 199 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 200 return _rw_lock_read_lock(lock); 201 return B_OK; 202 #endif 203 } 204 205 206 static inline status_t 207 rw_lock_read_lock_with_timeout(rw_lock* lock, uint32 timeoutFlags, 208 bigtime_t timeout) 209 { 210 #if KDEBUG_RW_LOCK_DEBUG 211 return _rw_lock_read_lock_with_timeout(lock, timeoutFlags, timeout); 212 #else 213 int32 oldCount = atomic_add(&lock->count, 1); 214 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 215 return _rw_lock_read_lock_with_timeout(lock, timeoutFlags, timeout); 216 return B_OK; 217 #endif 218 } 219 220 221 static inline void 222 rw_lock_read_unlock(rw_lock* lock) 223 { 224 #if KDEBUG_RW_LOCK_DEBUG 225 _rw_lock_read_unlock(lock); 226 #else 227 int32 oldCount = atomic_add(&lock->count, -1); 228 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 229 _rw_lock_read_unlock(lock); 230 #endif 231 } 232 233 234 static inline void 235 rw_lock_write_unlock(rw_lock* lock) 236 { 237 _rw_lock_write_unlock(lock); 238 } 239 240 241 #if !KDEBUG 242 static inline status_t 243 mutex_lock(mutex* lock) 244 { 245 if (atomic_add(&lock->count, -1) < 0) 246 return _mutex_lock(lock, NULL); 247 return B_OK; 248 } 249 250 251 static inline status_t 252 mutex_trylock(mutex* lock) 253 { 254 if (atomic_test_and_set(&lock->count, -1, 0) != 0) 255 return B_WOULD_BLOCK; 256 return B_OK; 257 } 258 259 260 static inline status_t 261 mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, bigtime_t timeout) 262 { 263 if (atomic_add(&lock->count, -1) < 0) 264 return _mutex_lock_with_timeout(lock, timeoutFlags, timeout); 265 return B_OK; 266 } 267 268 269 static inline void 270 mutex_unlock(mutex* lock) 271 { 272 if (atomic_add(&lock->count, 1) < -1) 273 _mutex_unlock(lock); 274 } 275 #endif 276 277 278 static inline void 279 recursive_lock_transfer_lock(recursive_lock* lock, thread_id thread) 280 { 281 if (lock->recursion != 1) 282 panic("invalid recursion level for lock transfer!"); 283 284 #if KDEBUG 285 mutex_transfer_lock(&lock->lock, thread); 286 #else 287 lock->holder = thread; 288 #endif 289 } 290 291 292 extern void lock_debug_init(); 293 294 #ifdef __cplusplus 295 } 296 #endif 297 298 #endif /* _KERNEL_LOCK_H */ 299