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 uint16 ignore_unlock_count; 30 #endif 31 uint8 flags; 32 } mutex; 33 34 #define MUTEX_FLAG_CLONE_NAME 0x1 35 36 37 typedef struct recursive_lock { 38 mutex lock; 39 #if !KDEBUG 40 thread_id holder; 41 #endif 42 int recursion; 43 } recursive_lock; 44 45 46 struct rw_lock_waiter; 47 48 typedef struct rw_lock { 49 const char* name; 50 struct rw_lock_waiter* waiters; 51 spinlock lock; 52 thread_id holder; 53 int32 count; 54 int32 owner_count; 55 int16 active_readers; 56 // Only > 0 while a writer is waiting: number 57 // of active readers when the first waiting 58 // writer started waiting. 59 int16 pending_readers; 60 // Number of readers that have already 61 // incremented "count", but have not yet started 62 // to wait at the time the last writer unlocked. 63 uint32 flags; 64 } rw_lock; 65 66 #define RW_LOCK_WRITER_COUNT_BASE 0x10000 67 68 #define RW_LOCK_FLAG_CLONE_NAME 0x1 69 70 71 #if KDEBUG 72 # define KDEBUG_RW_LOCK_DEBUG 0 73 // Define to 1 if you want to use ASSERT_READ_LOCKED_RW_LOCK(). 74 // The rw_lock will just behave like a recursive locker then. 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 # define ASSERT_READ_LOCKED_RW_LOCK(l) \ 82 { ASSERT(find_thread(NULL) == (l)->holder); } 83 # else 84 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 85 # endif 86 #else 87 # define ASSERT_LOCKED_RECURSIVE(r) do {} while (false) 88 # define ASSERT_LOCKED_MUTEX(m) do {} while (false) 89 # define ASSERT_WRITE_LOCKED_RW_LOCK(m) do {} while (false) 90 # define ASSERT_READ_LOCKED_RW_LOCK(l) do {} while (false) 91 #endif 92 93 94 // static initializers 95 #if KDEBUG 96 # define MUTEX_INITIALIZER(name) \ 97 { name, NULL, B_SPINLOCK_INITIALIZER, -1, 0 } 98 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), 0 } 99 #else 100 # define MUTEX_INITIALIZER(name) \ 101 { name, NULL, B_SPINLOCK_INITIALIZER, 0, 0, 0 } 102 # define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), -1, 0 } 103 #endif 104 105 #define RW_LOCK_INITIALIZER(name) \ 106 { name, NULL, B_SPINLOCK_INITIALIZER, -1, 0, 0, 0, 0, 0 } 107 108 109 #if KDEBUG 110 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->lock.holder) 111 #else 112 # define RECURSIVE_LOCK_HOLDER(recursiveLock) ((recursiveLock)->holder) 113 #endif 114 115 116 #ifdef __cplusplus 117 extern "C" { 118 #endif 119 120 extern void recursive_lock_init(recursive_lock *lock, const char *name); 121 // name is *not* cloned nor freed in recursive_lock_destroy() 122 extern void recursive_lock_init_etc(recursive_lock *lock, const char *name, 123 uint32 flags); 124 extern void recursive_lock_destroy(recursive_lock *lock); 125 extern status_t recursive_lock_lock(recursive_lock *lock); 126 extern status_t recursive_lock_trylock(recursive_lock *lock); 127 extern void recursive_lock_unlock(recursive_lock *lock); 128 extern int32 recursive_lock_get_recursion(recursive_lock *lock); 129 130 extern void rw_lock_init(rw_lock* lock, const char* name); 131 // name is *not* cloned nor freed in rw_lock_destroy() 132 extern void rw_lock_init_etc(rw_lock* lock, const char* name, uint32 flags); 133 extern void rw_lock_destroy(rw_lock* lock); 134 extern status_t rw_lock_write_lock(rw_lock* lock); 135 136 extern void mutex_init(mutex* lock, const char* name); 137 // name is *not* cloned nor freed in mutex_destroy() 138 extern void mutex_init_etc(mutex* lock, const char* name, uint32 flags); 139 extern void mutex_destroy(mutex* lock); 140 extern void mutex_transfer_lock(mutex* lock, thread_id thread); 141 extern status_t mutex_switch_lock(mutex* from, mutex* to); 142 // Unlocks "from" and locks "to" such that unlocking and starting to wait 143 // for the lock is atomically. I.e. if "from" guards the object "to" belongs 144 // to, the operation is safe as long as "from" is held while destroying 145 // "to". 146 extern status_t mutex_switch_from_read_lock(rw_lock* from, mutex* to); 147 // Like mutex_switch_lock(), just for a switching from a read-locked 148 // rw_lock. 149 150 151 // implementation private: 152 153 extern status_t _rw_lock_read_lock(rw_lock* lock); 154 extern status_t _rw_lock_read_lock_with_timeout(rw_lock* lock, 155 uint32 timeoutFlags, bigtime_t timeout); 156 extern void _rw_lock_read_unlock(rw_lock* lock); 157 extern void _rw_lock_write_unlock(rw_lock* lock); 158 159 extern status_t _mutex_lock(mutex* lock, void* locker); 160 extern void _mutex_unlock(mutex* lock); 161 extern status_t _mutex_trylock(mutex* lock); 162 extern status_t _mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, 163 bigtime_t timeout); 164 165 166 static inline status_t 167 rw_lock_read_lock(rw_lock* lock) 168 { 169 #if KDEBUG_RW_LOCK_DEBUG 170 return rw_lock_write_lock(lock); 171 #else 172 int32 oldCount = atomic_add(&lock->count, 1); 173 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 174 return _rw_lock_read_lock(lock); 175 return B_OK; 176 #endif 177 } 178 179 180 static inline status_t 181 rw_lock_read_lock_with_timeout(rw_lock* lock, uint32 timeoutFlags, 182 bigtime_t timeout) 183 { 184 #if KDEBUG_RW_LOCK_DEBUG 185 return mutex_lock_with_timeout(lock, timeoutFlags, timeout); 186 #else 187 int32 oldCount = atomic_add(&lock->count, 1); 188 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 189 return _rw_lock_read_lock_with_timeout(lock, timeoutFlags, timeout); 190 return B_OK; 191 #endif 192 } 193 194 195 static inline void 196 rw_lock_read_unlock(rw_lock* lock) 197 { 198 #if KDEBUG_RW_LOCK_DEBUG 199 rw_lock_write_unlock(lock); 200 #else 201 int32 oldCount = atomic_add(&lock->count, -1); 202 if (oldCount >= RW_LOCK_WRITER_COUNT_BASE) 203 _rw_lock_read_unlock(lock); 204 #endif 205 } 206 207 208 static inline void 209 rw_lock_write_unlock(rw_lock* lock) 210 { 211 _rw_lock_write_unlock(lock); 212 } 213 214 215 static inline status_t 216 mutex_lock(mutex* lock) 217 { 218 #if KDEBUG 219 return _mutex_lock(lock, NULL); 220 #else 221 if (atomic_add(&lock->count, -1) < 0) 222 return _mutex_lock(lock, NULL); 223 return B_OK; 224 #endif 225 } 226 227 228 static inline status_t 229 mutex_trylock(mutex* lock) 230 { 231 #if KDEBUG 232 return _mutex_trylock(lock); 233 #else 234 if (atomic_test_and_set(&lock->count, -1, 0) != 0) 235 return B_WOULD_BLOCK; 236 return B_OK; 237 #endif 238 } 239 240 241 static inline status_t 242 mutex_lock_with_timeout(mutex* lock, uint32 timeoutFlags, bigtime_t timeout) 243 { 244 #if KDEBUG 245 return _mutex_lock_with_timeout(lock, timeoutFlags, timeout); 246 #else 247 if (atomic_add(&lock->count, -1) < 0) 248 return _mutex_lock_with_timeout(lock, timeoutFlags, timeout); 249 return B_OK; 250 #endif 251 } 252 253 254 static inline void 255 mutex_unlock(mutex* lock) 256 { 257 #if !KDEBUG 258 if (atomic_add(&lock->count, 1) < -1) 259 #endif 260 _mutex_unlock(lock); 261 } 262 263 264 static inline void 265 recursive_lock_transfer_lock(recursive_lock* lock, thread_id thread) 266 { 267 if (lock->recursion != 1) 268 panic("invalid recursion level for lock transfer!"); 269 270 #if KDEBUG 271 mutex_transfer_lock(&lock->lock, thread); 272 #else 273 lock->holder = thread; 274 #endif 275 } 276 277 278 extern void lock_debug_init(); 279 280 #ifdef __cplusplus 281 } 282 #endif 283 284 #endif /* _KERNEL_LOCK_H */ 285