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 #ifdef CONFIG_DEBUG_LOCK_ALLOC 26 # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ 27 , .dep_map = { \ 28 .name = #lockname, \ 29 .wait_type_inner = LD_WAIT_SLEEP, \ 30 } 31 #else 32 # define __DEP_MAP_MUTEX_INITIALIZER(lockname) 33 #endif 34 35 #ifndef CONFIG_PREEMPT_RT 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 #define __MUTEX_INITIALIZER(lockname) \ 68 { .owner = ATOMIC_LONG_INIT(0) \ 69 , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ 70 , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \ 71 __DEBUG_MUTEX_INITIALIZER(lockname) \ 72 __DEP_MAP_MUTEX_INITIALIZER(lockname) } 73 74 #define DEFINE_MUTEX(mutexname) \ 75 struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) 76 77 extern void __mutex_init(struct mutex *lock, const char *name, 78 struct lock_class_key *key); 79 80 /** 81 * mutex_is_locked - is the mutex locked 82 * @lock: the mutex to be queried 83 * 84 * Returns true if the mutex is locked, false if unlocked. 85 */ 86 extern bool mutex_is_locked(struct mutex *lock); 87 88 #else /* !CONFIG_PREEMPT_RT */ 89 /* 90 * Preempt-RT variant based on rtmutexes. 91 */ 92 93 #define __MUTEX_INITIALIZER(mutexname) \ 94 { \ 95 .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \ 96 __DEP_MAP_MUTEX_INITIALIZER(mutexname) \ 97 } 98 99 #define DEFINE_MUTEX(mutexname) \ 100 struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) 101 102 extern void __mutex_rt_init(struct mutex *lock, const char *name, 103 struct lock_class_key *key); 104 extern int mutex_trylock(struct mutex *lock); 105 106 static inline void mutex_destroy(struct mutex *lock) { } 107 108 #define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) 109 110 #define __mutex_init(mutex, name, key) \ 111 do { \ 112 rt_mutex_base_init(&(mutex)->rtmutex); \ 113 __mutex_rt_init((mutex), name, key); \ 114 } while (0) 115 116 #define mutex_init(mutex) \ 117 do { \ 118 static struct lock_class_key __key; \ 119 \ 120 __mutex_init((mutex), #mutex, &__key); \ 121 } while (0) 122 #endif /* CONFIG_PREEMPT_RT */ 123 124 /* 125 * See kernel/locking/mutex.c for detailed documentation of these APIs. 126 * Also see Documentation/locking/mutex-design.rst. 127 */ 128 #ifdef CONFIG_DEBUG_LOCK_ALLOC 129 extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); 130 extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock); 131 132 extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, 133 unsigned int subclass); 134 extern int __must_check mutex_lock_killable_nested(struct mutex *lock, 135 unsigned int subclass); 136 extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass); 137 138 #define mutex_lock(lock) mutex_lock_nested(lock, 0) 139 #define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0) 140 #define mutex_lock_killable(lock) mutex_lock_killable_nested(lock, 0) 141 #define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0) 142 143 #define mutex_lock_nest_lock(lock, nest_lock) \ 144 do { \ 145 typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ 146 _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \ 147 } while (0) 148 149 #else 150 extern void mutex_lock(struct mutex *lock); 151 extern int __must_check mutex_lock_interruptible(struct mutex *lock); 152 extern int __must_check mutex_lock_killable(struct mutex *lock); 153 extern void mutex_lock_io(struct mutex *lock); 154 155 # define mutex_lock_nested(lock, subclass) mutex_lock(lock) 156 # define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock) 157 # define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock) 158 # define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock) 159 # define mutex_lock_io_nested(lock, subclass) mutex_lock_io(lock) 160 #endif 161 162 /* 163 * NOTE: mutex_trylock() follows the spin_trylock() convention, 164 * not the down_trylock() convention! 165 * 166 * Returns 1 if the mutex has been acquired successfully, and 0 on contention. 167 */ 168 extern int mutex_trylock(struct mutex *lock); 169 extern void mutex_unlock(struct mutex *lock); 170 171 extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); 172 173 DEFINE_GUARD(mutex, struct mutex *, mutex_lock(_T), mutex_unlock(_T)) 174 DEFINE_GUARD_COND(mutex, _try, mutex_trylock(_T)) 175 DEFINE_GUARD_COND(mutex, _intr, mutex_lock_interruptible(_T) == 0) 176 177 #endif /* __LINUX_MUTEX_H */ 178