1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Mutexes: blocking mutual exclusion locks 4 * 5 * started by Ingo Molnar: 6 * 7 * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <[email protected]> 8 * 9 * This file contains the main data structure and API definitions. 10 */ 11 #ifndef __LINUX_MUTEX_H 12 #define __LINUX_MUTEX_H 13 14 #include <asm/current.h> 15 #include <linux/list.h> 16 #include <linux/spinlock_types.h> 17 #include <linux/lockdep.h> 18 #include <linux/atomic.h> 19 #include <asm/processor.h> 20 #include <linux/osq_lock.h> 21 #include <linux/debug_locks.h> 22 #include <linux/cleanup.h> 23 #include <linux/mutex_types.h> 24 25 struct device; 26 27 #ifdef CONFIG_DEBUG_LOCK_ALLOC 28 # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ 29 , .dep_map = { \ 30 .name = #lockname, \ 31 .wait_type_inner = LD_WAIT_SLEEP, \ 32 } 33 #else 34 # define __DEP_MAP_MUTEX_INITIALIZER(lockname) 35 #endif 36 37 #ifdef CONFIG_DEBUG_MUTEXES 38 39 # define __DEBUG_MUTEX_INITIALIZER(lockname) \ 40 , .magic = &lockname 41 42 extern void mutex_destroy(struct mutex *lock); 43 44 #else 45 46 # define __DEBUG_MUTEX_INITIALIZER(lockname) 47 48 static inline void mutex_destroy(struct mutex *lock) {} 49 50 #endif 51 52 /** 53 * mutex_init - initialize the mutex 54 * @mutex: the mutex to be initialized 55 * 56 * Initialize the mutex to unlocked state. 57 * 58 * It is not allowed to initialize an already locked mutex. 59 */ 60 #define mutex_init(mutex) \ 61 do { \ 62 static struct lock_class_key __key; \ 63 \ 64 __mutex_init((mutex), #mutex, &__key); \ 65 } while (0) 66 67 /** 68 * mutex_init_with_key - initialize a mutex with a given lockdep key 69 * @mutex: the mutex to be initialized 70 * @key: the lockdep key to be associated with the mutex 71 * 72 * Initialize the mutex to the unlocked state. 73 * 74 * It is not allowed to initialize an already locked mutex. 75 */ 76 #define mutex_init_with_key(mutex, key) __mutex_init((mutex), #mutex, (key)) 77 78 #ifndef CONFIG_PREEMPT_RT 79 #define __MUTEX_INITIALIZER(lockname) \ 80 { .owner = ATOMIC_LONG_INIT(0) \ 81 , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ 82 , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \ 83 __DEBUG_MUTEX_INITIALIZER(lockname) \ 84 __DEP_MAP_MUTEX_INITIALIZER(lockname) } 85 86 #define DEFINE_MUTEX(mutexname) \ 87 struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) 88 89 extern void __mutex_init(struct mutex *lock, const char *name, 90 struct lock_class_key *key); 91 92 /** 93 * mutex_is_locked - is the mutex locked 94 * @lock: the mutex to be queried 95 * 96 * Returns true if the mutex is locked, false if unlocked. 97 */ 98 extern bool mutex_is_locked(struct mutex *lock); 99 100 #else /* !CONFIG_PREEMPT_RT */ 101 /* 102 * Preempt-RT variant based on rtmutexes. 103 */ 104 105 #define __MUTEX_INITIALIZER(mutexname) \ 106 { \ 107 .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \ 108 __DEP_MAP_MUTEX_INITIALIZER(mutexname) \ 109 } 110 111 #define DEFINE_MUTEX(mutexname) \ 112 struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) 113 114 extern void __mutex_rt_init(struct mutex *lock, const char *name, 115 struct lock_class_key *key); 116 117 #define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) 118 119 #define __mutex_init(mutex, name, key) \ 120 do { \ 121 rt_mutex_base_init(&(mutex)->rtmutex); \ 122 __mutex_rt_init((mutex), name, key); \ 123 } while (0) 124 125 #endif /* CONFIG_PREEMPT_RT */ 126 127 #ifdef CONFIG_DEBUG_MUTEXES 128 129 int __devm_mutex_init(struct device *dev, struct mutex *lock); 130 131 #else 132 133 static inline int __devm_mutex_init(struct device *dev, struct mutex *lock) 134 { 135 /* 136 * When CONFIG_DEBUG_MUTEXES is off mutex_destroy() is just a nop so 137 * no really need to register it in the devm subsystem. 138 */ 139 return 0; 140 } 141 142 #endif 143 144 #define devm_mutex_init(dev, mutex) \ 145 ({ \ 146 typeof(mutex) mutex_ = (mutex); \ 147 \ 148 mutex_init(mutex_); \ 149 __devm_mutex_init(dev, mutex_); \ 150 }) 151 152 /* 153 * See kernel/locking/mutex.c for detailed documentation of these APIs. 154 * Also see Documentation/locking/mutex-design.rst. 155 */ 156 #ifdef CONFIG_DEBUG_LOCK_ALLOC 157 extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); 158 extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock); 159 160 extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, 161 unsigned int subclass); 162 extern int __must_check mutex_lock_killable_nested(struct mutex *lock, 163 unsigned int subclass); 164 extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass); 165 166 #define mutex_lock(lock) mutex_lock_nested(lock, 0) 167 #define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0) 168 #define mutex_lock_killable(lock) mutex_lock_killable_nested(lock, 0) 169 #define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0) 170 171 #define mutex_lock_nest_lock(lock, nest_lock) \ 172 do { \ 173 typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ 174 _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \ 175 } while (0) 176 177 #else 178 extern void mutex_lock(struct mutex *lock); 179 extern int __must_check mutex_lock_interruptible(struct mutex *lock); 180 extern int __must_check mutex_lock_killable(struct mutex *lock); 181 extern void mutex_lock_io(struct mutex *lock); 182 183 # define mutex_lock_nested(lock, subclass) mutex_lock(lock) 184 # define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock) 185 # define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock) 186 # define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock) 187 # define mutex_lock_io_nested(lock, subclass) mutex_lock_io(lock) 188 #endif 189 190 /* 191 * NOTE: mutex_trylock() follows the spin_trylock() convention, 192 * not the down_trylock() convention! 193 * 194 * Returns 1 if the mutex has been acquired successfully, and 0 on contention. 195 */ 196 extern int mutex_trylock(struct mutex *lock); 197 extern void mutex_unlock(struct mutex *lock); 198 199 extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); 200 201 DEFINE_GUARD(mutex, struct mutex *, mutex_lock(_T), mutex_unlock(_T)) 202 DEFINE_GUARD_COND(mutex, _try, mutex_trylock(_T)) 203 DEFINE_GUARD_COND(mutex, _intr, mutex_lock_interruptible(_T) == 0) 204 205 extern unsigned long mutex_get_owner(struct mutex *lock); 206 207 #endif /* __LINUX_MUTEX_H */ 208