/* SPDX-License-Identifier: GPL-2.0 */ /* * Mutexes: blocking mutual exclusion locks * * started by Ingo Molnar: * * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <[email protected]> * * This file contains the main data structure and API definitions. */ #ifndef __LINUX_MUTEX_H #define __LINUX_MUTEX_H #include <asm/current.h> #include <linux/list.h> #include <linux/spinlock_types.h> #include <linux/lockdep.h> #include <linux/atomic.h> #include <asm/processor.h> #include <linux/osq_lock.h> #include <linux/debug_locks.h> #include <linux/cleanup.h> #include <linux/mutex_types.h> struct device; #ifdef CONFIG_DEBUG_LOCK_ALLOC #define __DEP_MAP_MUTEX_INITIALIZER(lockname) … #else #define __DEP_MAP_MUTEX_INITIALIZER … #endif #ifdef CONFIG_DEBUG_MUTEXES #define __DEBUG_MUTEX_INITIALIZER(lockname) … extern void mutex_destroy(struct mutex *lock); #else #define __DEBUG_MUTEX_INITIALIZER … static inline void mutex_destroy(struct mutex *lock) {} #endif #ifndef CONFIG_PREEMPT_RT /** * mutex_init - initialize the mutex * @mutex: the mutex to be initialized * * Initialize the mutex to unlocked state. * * It is not allowed to initialize an already locked mutex. */ #define mutex_init(mutex) … #define __MUTEX_INITIALIZER(lockname) … #define DEFINE_MUTEX(mutexname) … extern void __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key); /** * mutex_is_locked - is the mutex locked * @lock: the mutex to be queried * * Returns true if the mutex is locked, false if unlocked. */ extern bool mutex_is_locked(struct mutex *lock); #else /* !CONFIG_PREEMPT_RT */ /* * Preempt-RT variant based on rtmutexes. */ #define __MUTEX_INITIALIZER … #define DEFINE_MUTEX … extern void __mutex_rt_init(struct mutex *lock, const char *name, struct lock_class_key *key); #define mutex_is_locked … #define __mutex_init … #define mutex_init … #endif /* CONFIG_PREEMPT_RT */ #ifdef CONFIG_DEBUG_MUTEXES int __devm_mutex_init(struct device *dev, struct mutex *lock); #else static inline int __devm_mutex_init(struct device *dev, struct mutex *lock) { /* * When CONFIG_DEBUG_MUTEXES is off mutex_destroy() is just a nop so * no really need to register it in the devm subsystem. */ return 0; } #endif #define devm_mutex_init(dev, mutex) … /* * See kernel/locking/mutex.c for detailed documentation of these APIs. * Also see Documentation/locking/mutex-design.rst. */ #ifdef CONFIG_DEBUG_LOCK_ALLOC extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); extern void _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock); extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass); extern int __must_check mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass); extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass); #define mutex_lock(lock) … #define mutex_lock_interruptible(lock) … #define mutex_lock_killable(lock) … #define mutex_lock_io(lock) … #define mutex_lock_nest_lock(lock, nest_lock) … #else extern void mutex_lock(struct mutex *lock); extern int __must_check mutex_lock_interruptible(struct mutex *lock); extern int __must_check mutex_lock_killable(struct mutex *lock); extern void mutex_lock_io(struct mutex *lock); #define mutex_lock_nested … #define mutex_lock_interruptible_nested … #define mutex_lock_killable_nested … #define mutex_lock_nest_lock … #define mutex_lock_io_nested … #endif /* * NOTE: mutex_trylock() follows the spin_trylock() convention, * not the down_trylock() convention! * * Returns 1 if the mutex has been acquired successfully, and 0 on contention. */ extern int mutex_trylock(struct mutex *lock); extern void mutex_unlock(struct mutex *lock); extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); DEFINE_GUARD(mutex, struct mutex *, mutex_lock(_T), mutex_unlock(_T)) DEFINE_GUARD_COND(mutex, _try, mutex_trylock(_T)) DEFINE_GUARD_COND(mutex, _intr, mutex_lock_interruptible(_T) == 0) #endif /* __LINUX_MUTEX_H */
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