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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * Mutexes: blocking mutual exclusion locks4 *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_H12#define __LINUX_MUTEX_H13 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_ALLOC28# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \29 , .dep_map = { \30 .name = #lockname, \31 .wait_type_inner = LD_WAIT_SLEEP, \32 }33#else34# define __DEP_MAP_MUTEX_INITIALIZER(lockname)35#endif36 37#ifdef CONFIG_DEBUG_MUTEXES38 39# define __DEBUG_MUTEX_INITIALIZER(lockname) \40 , .magic = &lockname41 42extern void mutex_destroy(struct mutex *lock);43 44#else45 46# define __DEBUG_MUTEX_INITIALIZER(lockname)47 48static inline void mutex_destroy(struct mutex *lock) {}49 50#endif51 52/**53 * mutex_init - initialize the mutex54 * @mutex: the mutex to be initialized55 *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 key69 * @mutex: the mutex to be initialized70 * @key: the lockdep key to be associated with the mutex71 *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_RT79#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 89extern void __mutex_init(struct mutex *lock, const char *name,90 struct lock_class_key *key);91 92/**93 * mutex_is_locked - is the mutex locked94 * @lock: the mutex to be queried95 *96 * Returns true if the mutex is locked, false if unlocked.97 */98extern 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 114extern 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) \120do { \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_MUTEXES128 129int __devm_mutex_init(struct device *dev, struct mutex *lock);130 131#else132 133static 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 so137 * no really need to register it in the devm subsystem.138 */139 return 0;140}141 142#endif143 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_ALLOC157extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass);158extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);159 160extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock,161 unsigned int subclass);162extern int __must_check mutex_lock_killable_nested(struct mutex *lock,163 unsigned int subclass);164extern 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) \172do { \173 typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \174 _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \175} while (0)176 177#else178extern void mutex_lock(struct mutex *lock);179extern int __must_check mutex_lock_interruptible(struct mutex *lock) HWJS_SUSPENDS;180extern int __must_check mutex_lock_killable(struct mutex *lock) HWJS_SUSPENDS;181extern void mutex_lock_io(struct mutex *lock) HWJS_SUSPENDS;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#endif189 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 */196extern int mutex_trylock(struct mutex *lock);197extern void mutex_unlock(struct mutex *lock) HWJS_SUSPENDS;198 199extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock) HWJS_SUSPENDS;200 201DEFINE_GUARD(mutex, struct mutex *, mutex_lock(_T), mutex_unlock(_T))202DEFINE_GUARD_COND(mutex, _try, mutex_trylock(_T))203DEFINE_GUARD_COND(mutex, _intr, mutex_lock_interruptible(_T) == 0)204 205#endif /* __LINUX_MUTEX_H */206