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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
25struct 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
42extern void mutex_destroy(struct mutex *lock);
43
44#else
45
46# define __DEBUG_MUTEX_INITIALIZER(lockname)
47
48static 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) \
61do { \
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 , .first_waiter = NULL \
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
90void mutex_init_lockdep(struct mutex *lock, const char *name, struct lock_class_key *key);
91
92static inline void __mutex_init(struct mutex *lock, const char *name,
93 struct lock_class_key *key)
94{
95 mutex_init_lockdep(lock, name, key);
96}
97#else
98extern void mutex_init_generic(struct mutex *lock);
99
100static inline void __mutex_init(struct mutex *lock, const char *name,
101 struct lock_class_key *key)
102{
103 mutex_init_generic(lock);
104}
105#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
106
107/**
108 * mutex_is_locked - is the mutex locked
109 * @lock: the mutex to be queried
110 *
111 * Returns true if the mutex is locked, false if unlocked.
112 */
113extern bool mutex_is_locked(struct mutex *lock);
114
115#else /* !CONFIG_PREEMPT_RT */
116/*
117 * Preempt-RT variant based on rtmutexes.
118 */
119
120#define __MUTEX_INITIALIZER(mutexname) \
121{ \
122 .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \
123 __DEP_MAP_MUTEX_INITIALIZER(mutexname) \
124}
125
126#define DEFINE_MUTEX(mutexname) \
127 struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
128
129#define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex)
130
131#ifdef CONFIG_DEBUG_LOCK_ALLOC
132extern void mutex_rt_init_lockdep(struct mutex *mutex, const char *name,
133 struct lock_class_key *key);
134
135static inline void __mutex_init(struct mutex *lock, const char *name,
136 struct lock_class_key *key)
137{
138 mutex_rt_init_lockdep(lock, name, key);
139}
140
141#else
142extern void mutex_rt_init_generic(struct mutex *mutex);
143
144static inline void __mutex_init(struct mutex *lock, const char *name,
145 struct lock_class_key *key)
146{
147 mutex_rt_init_generic(lock);
148}
149#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
150#endif /* CONFIG_PREEMPT_RT */
151
152#ifdef CONFIG_DEBUG_MUTEXES
153
154int __must_check __devm_mutex_init(struct device *dev, struct mutex *lock);
155
156#else
157
158static inline int __must_check __devm_mutex_init(struct device *dev, struct mutex *lock)
159{
160 /*
161 * When CONFIG_DEBUG_MUTEXES is off mutex_destroy() is just a nop so
162 * no really need to register it in the devm subsystem.
163 */
164 return 0;
165}
166
167#endif
168
169#define __mutex_init_ret(mutex) \
170({ \
171 typeof(mutex) mutex_ = (mutex); \
172 \
173 mutex_init(mutex_); \
174 mutex_; \
175})
176
177#define devm_mutex_init(dev, mutex) \
178 __devm_mutex_init(dev, __mutex_init_ret(mutex))
179
180/*
181 * See kernel/locking/mutex.c for detailed documentation of these APIs.
182 * Also see Documentation/locking/mutex-design.rst.
183 */
184#ifdef CONFIG_DEBUG_LOCK_ALLOC
185extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass) __acquires(lock);
186extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock) __acquires(lock);
187extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock,
188 unsigned int subclass) __cond_acquires(0, lock);
189extern int __must_check _mutex_lock_killable(struct mutex *lock,
190 unsigned int subclass, struct lockdep_map *nest_lock) __cond_acquires(0, lock);
191extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass) __acquires(lock);
192
193#define mutex_lock(lock) mutex_lock_nested(lock, 0)
194#define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0)
195#define mutex_lock_killable(lock) _mutex_lock_killable(lock, 0, NULL)
196#define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0)
197
198#define mutex_lock_nest_lock(lock, nest_lock) \
199do { \
200 typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
201 _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \
202} while (0)
203
204#define mutex_lock_killable_nest_lock(lock, nest_lock) \
205( \
206 typecheck(struct lockdep_map *, &(nest_lock)->dep_map), \
207 _mutex_lock_killable(lock, 0, &(nest_lock)->dep_map) \
208)
209
210#define mutex_lock_killable_nested(lock, subclass) \
211 _mutex_lock_killable(lock, subclass, NULL)
212
213#else
214extern void mutex_lock(struct mutex *lock) __acquires(lock);
215extern int __must_check mutex_lock_interruptible(struct mutex *lock) __cond_acquires(0, lock);
216extern int __must_check mutex_lock_killable(struct mutex *lock) __cond_acquires(0, lock);
217extern void mutex_lock_io(struct mutex *lock) __acquires(lock);
218
219# define mutex_lock_nested(lock, subclass) mutex_lock(lock)
220# define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock)
221# define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock)
222# define mutex_lock_killable_nest_lock(lock, nest_lock) mutex_lock_killable(lock)
223# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
224# define mutex_lock_io_nested(lock, subclass) mutex_lock_io(lock)
225#endif
226
227/*
228 * NOTE: mutex_trylock() follows the spin_trylock() convention,
229 * not the down_trylock() convention!
230 *
231 * Returns 1 if the mutex has been acquired successfully, and 0 on contention.
232 */
233
234#ifdef CONFIG_DEBUG_LOCK_ALLOC
235extern int _mutex_trylock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock) __cond_acquires(true, lock);
236
237#define mutex_trylock_nest_lock(lock, nest_lock) \
238( \
239 typecheck(struct lockdep_map *, &(nest_lock)->dep_map), \
240 _mutex_trylock_nest_lock(lock, &(nest_lock)->dep_map) \
241)
242
243#define mutex_trylock(lock) _mutex_trylock_nest_lock(lock, NULL)
244#else
245extern int mutex_trylock(struct mutex *lock) __cond_acquires(true, lock);
246#define mutex_trylock_nest_lock(lock, nest_lock) mutex_trylock(lock)
247#endif
248
249extern void mutex_unlock(struct mutex *lock) __releases(lock);
250
251extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock) __cond_acquires(true, lock);
252
253DEFINE_LOCK_GUARD_1(mutex, struct mutex, mutex_lock(_T->lock), mutex_unlock(_T->lock))
254DEFINE_LOCK_GUARD_1_COND(mutex, _try, mutex_trylock(_T->lock))
255DEFINE_LOCK_GUARD_1_COND(mutex, _intr, mutex_lock_interruptible(_T->lock), _RET == 0)
256DEFINE_LOCK_GUARD_1_COND(mutex, _kill, mutex_lock_killable(_T->lock), _RET == 0)
257DEFINE_LOCK_GUARD_1(mutex_init, struct mutex, mutex_init(_T->lock), /* */)
258
259DECLARE_LOCK_GUARD_1_ATTRS(mutex, __acquires(_T), __releases(*(struct mutex **)_T))
260#define class_mutex_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex, _T)
261DECLARE_LOCK_GUARD_1_ATTRS(mutex_try, __acquires(_T), __releases(*(struct mutex **)_T))
262#define class_mutex_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex_try, _T)
263DECLARE_LOCK_GUARD_1_ATTRS(mutex_intr, __acquires(_T), __releases(*(struct mutex **)_T))
264#define class_mutex_intr_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex_intr, _T)
265DECLARE_LOCK_GUARD_1_ATTRS(mutex_kill, __acquires(_T), __releases(*(struct mutex **)_T))
266#define class_mutex_kill_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex_kill, _T)
267DECLARE_LOCK_GUARD_1_ATTRS(mutex_init, __acquires(_T), __releases(*(struct mutex **)_T))
268#define class_mutex_init_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex_init, _T)
269
270extern unsigned long mutex_get_owner(struct mutex *lock);
271
272#endif /* __LINUX_MUTEX_H */