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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
6053ee3b IM |
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 <mingo@redhat.com> | |
8 | * | |
9 | * This file contains the main data structure and API definitions. | |
10 | */ | |
11 | #ifndef __LINUX_MUTEX_H | |
12 | #define __LINUX_MUTEX_H | |
13 | ||
040a0a37 | 14 | #include <asm/current.h> |
6053ee3b IM |
15 | #include <linux/list.h> |
16 | #include <linux/spinlock_types.h> | |
ef5d4707 | 17 | #include <linux/lockdep.h> |
60063497 | 18 | #include <linux/atomic.h> |
083986e8 | 19 | #include <asm/processor.h> |
90631822 | 20 | #include <linux/osq_lock.h> |
3ca0ff57 | 21 | #include <linux/debug_locks.h> |
6053ee3b | 22 | |
bb630f9f TG |
23 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
24 | # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ | |
25 | , .dep_map = { \ | |
26 | .name = #lockname, \ | |
27 | .wait_type_inner = LD_WAIT_SLEEP, \ | |
28 | } | |
29 | #else | |
30 | # define __DEP_MAP_MUTEX_INITIALIZER(lockname) | |
31 | #endif | |
32 | ||
33 | #ifndef CONFIG_PREEMPT_RT | |
34 | ||
6053ee3b IM |
35 | /* |
36 | * Simple, straightforward mutexes with strict semantics: | |
37 | * | |
38 | * - only one task can hold the mutex at a time | |
39 | * - only the owner can unlock the mutex | |
40 | * - multiple unlocks are not permitted | |
41 | * - recursive locking is not permitted | |
42 | * - a mutex object must be initialized via the API | |
43 | * - a mutex object must not be initialized via memset or copying | |
44 | * - task may not exit with mutex held | |
45 | * - memory areas where held locks reside must not be freed | |
46 | * - held mutexes must not be reinitialized | |
f20fda48 ML |
47 | * - mutexes may not be used in hardware or software interrupt |
48 | * contexts such as tasklets and timers | |
6053ee3b IM |
49 | * |
50 | * These semantics are fully enforced when DEBUG_MUTEXES is | |
51 | * enabled. Furthermore, besides enforcing the above rules, the mutex | |
52 | * debugging code also implements a number of additional features | |
53 | * that make lock debugging easier and faster: | |
54 | * | |
55 | * - uses symbolic names of mutexes, whenever they are printed in debug output | |
56 | * - point-of-acquire tracking, symbolic lookup of function names | |
57 | * - list of all locks held in the system, printout of them | |
58 | * - owner tracking | |
59 | * - detects self-recursing locks and prints out all relevant info | |
60 | * - detects multi-task circular deadlocks and prints out all affected | |
61 | * locks and tasks (and only those tasks) | |
62 | */ | |
63 | struct mutex { | |
3ca0ff57 | 64 | atomic_long_t owner; |
ebf4c55c | 65 | raw_spinlock_t wait_lock; |
2bd2c92c | 66 | #ifdef CONFIG_MUTEX_SPIN_ON_OWNER |
90631822 | 67 | struct optimistic_spin_queue osq; /* Spinner MCS lock */ |
2bd2c92c | 68 | #endif |
3ca0ff57 | 69 | struct list_head wait_list; |
0d66bf6d | 70 | #ifdef CONFIG_DEBUG_MUTEXES |
6053ee3b IM |
71 | void *magic; |
72 | #endif | |
ef5d4707 IM |
73 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
74 | struct lockdep_map dep_map; | |
75 | #endif | |
6053ee3b IM |
76 | }; |
77 | ||
6053ee3b | 78 | #ifdef CONFIG_DEBUG_MUTEXES |
3ca0ff57 PZ |
79 | |
80 | #define __DEBUG_MUTEX_INITIALIZER(lockname) \ | |
81 | , .magic = &lockname | |
82 | ||
83 | extern void mutex_destroy(struct mutex *lock); | |
84 | ||
6053ee3b | 85 | #else |
3ca0ff57 | 86 | |
6053ee3b | 87 | # define __DEBUG_MUTEX_INITIALIZER(lockname) |
3ca0ff57 PZ |
88 | |
89 | static inline void mutex_destroy(struct mutex *lock) {} | |
90 | ||
91 | #endif | |
92 | ||
ef5dc121 RD |
93 | /** |
94 | * mutex_init - initialize the mutex | |
95 | * @mutex: the mutex to be initialized | |
96 | * | |
97 | * Initialize the mutex to unlocked state. | |
98 | * | |
99 | * It is not allowed to initialize an already locked mutex. | |
100 | */ | |
3ca0ff57 PZ |
101 | #define mutex_init(mutex) \ |
102 | do { \ | |
103 | static struct lock_class_key __key; \ | |
104 | \ | |
105 | __mutex_init((mutex), #mutex, &__key); \ | |
ef5d4707 | 106 | } while (0) |
6053ee3b IM |
107 | |
108 | #define __MUTEX_INITIALIZER(lockname) \ | |
3ca0ff57 | 109 | { .owner = ATOMIC_LONG_INIT(0) \ |
ebf4c55c | 110 | , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ |
6053ee3b | 111 | , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \ |
ef5d4707 IM |
112 | __DEBUG_MUTEX_INITIALIZER(lockname) \ |
113 | __DEP_MAP_MUTEX_INITIALIZER(lockname) } | |
6053ee3b IM |
114 | |
115 | #define DEFINE_MUTEX(mutexname) \ | |
116 | struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) | |
117 | ||
ef5d4707 IM |
118 | extern void __mutex_init(struct mutex *lock, const char *name, |
119 | struct lock_class_key *key); | |
6053ee3b | 120 | |
45f8bde0 | 121 | /** |
6053ee3b IM |
122 | * mutex_is_locked - is the mutex locked |
123 | * @lock: the mutex to be queried | |
124 | * | |
db076bef | 125 | * Returns true if the mutex is locked, false if unlocked. |
6053ee3b | 126 | */ |
5f35d5a6 | 127 | extern bool mutex_is_locked(struct mutex *lock); |
6053ee3b | 128 | |
bb630f9f TG |
129 | #else /* !CONFIG_PREEMPT_RT */ |
130 | /* | |
131 | * Preempt-RT variant based on rtmutexes. | |
132 | */ | |
133 | #include <linux/rtmutex.h> | |
134 | ||
135 | struct mutex { | |
136 | struct rt_mutex_base rtmutex; | |
137 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
138 | struct lockdep_map dep_map; | |
139 | #endif | |
140 | }; | |
141 | ||
142 | #define __MUTEX_INITIALIZER(mutexname) \ | |
143 | { \ | |
144 | .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \ | |
145 | __DEP_MAP_MUTEX_INITIALIZER(mutexname) \ | |
146 | } | |
147 | ||
148 | #define DEFINE_MUTEX(mutexname) \ | |
149 | struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) | |
150 | ||
151 | extern void __mutex_rt_init(struct mutex *lock, const char *name, | |
152 | struct lock_class_key *key); | |
153 | extern int mutex_trylock(struct mutex *lock); | |
154 | ||
155 | static inline void mutex_destroy(struct mutex *lock) { } | |
156 | ||
157 | #define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) | |
158 | ||
159 | #define __mutex_init(mutex, name, key) \ | |
160 | do { \ | |
161 | rt_mutex_base_init(&(mutex)->rtmutex); \ | |
162 | __mutex_rt_init((mutex), name, key); \ | |
163 | } while (0) | |
164 | ||
165 | #define mutex_init(mutex) \ | |
166 | do { \ | |
167 | static struct lock_class_key __key; \ | |
168 | \ | |
169 | __mutex_init((mutex), #mutex, &__key); \ | |
170 | } while (0) | |
171 | #endif /* CONFIG_PREEMPT_RT */ | |
172 | ||
6053ee3b | 173 | /* |
67a6de49 | 174 | * See kernel/locking/mutex.c for detailed documentation of these APIs. |
387b1468 | 175 | * Also see Documentation/locking/mutex-design.rst. |
6053ee3b | 176 | */ |
ef5d4707 IM |
177 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
178 | extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); | |
e4c70a66 | 179 | extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock); |
040a0a37 | 180 | |
18d8362d AM |
181 | extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, |
182 | unsigned int subclass); | |
ad776537 LH |
183 | extern int __must_check mutex_lock_killable_nested(struct mutex *lock, |
184 | unsigned int subclass); | |
1460cb65 | 185 | extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass); |
e4564f79 PZ |
186 | |
187 | #define mutex_lock(lock) mutex_lock_nested(lock, 0) | |
188 | #define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0) | |
ad776537 | 189 | #define mutex_lock_killable(lock) mutex_lock_killable_nested(lock, 0) |
1460cb65 | 190 | #define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0) |
e4c70a66 PZ |
191 | |
192 | #define mutex_lock_nest_lock(lock, nest_lock) \ | |
193 | do { \ | |
040a0a37 | 194 | typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ |
e4c70a66 PZ |
195 | _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \ |
196 | } while (0) | |
197 | ||
ef5d4707 | 198 | #else |
ec701584 HH |
199 | extern void mutex_lock(struct mutex *lock); |
200 | extern int __must_check mutex_lock_interruptible(struct mutex *lock); | |
201 | extern int __must_check mutex_lock_killable(struct mutex *lock); | |
1460cb65 | 202 | extern void mutex_lock_io(struct mutex *lock); |
e4564f79 | 203 | |
ef5d4707 | 204 | # define mutex_lock_nested(lock, subclass) mutex_lock(lock) |
d63a5a74 | 205 | # define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock) |
ad776537 | 206 | # define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock) |
e4c70a66 | 207 | # define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock) |
291da9d4 | 208 | # define mutex_lock_io_nested(lock, subclass) mutex_lock_io(lock) |
ef5d4707 IM |
209 | #endif |
210 | ||
6053ee3b IM |
211 | /* |
212 | * NOTE: mutex_trylock() follows the spin_trylock() convention, | |
213 | * not the down_trylock() convention! | |
d98d38f2 AV |
214 | * |
215 | * Returns 1 if the mutex has been acquired successfully, and 0 on contention. | |
6053ee3b | 216 | */ |
ec701584 HH |
217 | extern int mutex_trylock(struct mutex *lock); |
218 | extern void mutex_unlock(struct mutex *lock); | |
040a0a37 | 219 | |
a511e3f9 | 220 | extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); |
b1fca266 | 221 | |
e7224674 | 222 | #endif /* __LINUX_MUTEX_H */ |