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- /* 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/android_vendor.h>
- #ifdef CONFIG_DEBUG_LOCK_ALLOC
- # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
- , .dep_map = { \
- .name = #lockname, \
- .wait_type_inner = LD_WAIT_SLEEP, \
- }
- #else
- # define __DEP_MAP_MUTEX_INITIALIZER(lockname)
- #endif
- #ifndef CONFIG_PREEMPT_RT
- /*
- * Simple, straightforward mutexes with strict semantics:
- *
- * - only one task can hold the mutex at a time
- * - only the owner can unlock the mutex
- * - multiple unlocks are not permitted
- * - recursive locking is not permitted
- * - a mutex object must be initialized via the API
- * - a mutex object must not be initialized via memset or copying
- * - task may not exit with mutex held
- * - memory areas where held locks reside must not be freed
- * - held mutexes must not be reinitialized
- * - mutexes may not be used in hardware or software interrupt
- * contexts such as tasklets and timers
- *
- * These semantics are fully enforced when DEBUG_MUTEXES is
- * enabled. Furthermore, besides enforcing the above rules, the mutex
- * debugging code also implements a number of additional features
- * that make lock debugging easier and faster:
- *
- * - uses symbolic names of mutexes, whenever they are printed in debug output
- * - point-of-acquire tracking, symbolic lookup of function names
- * - list of all locks held in the system, printout of them
- * - owner tracking
- * - detects self-recursing locks and prints out all relevant info
- * - detects multi-task circular deadlocks and prints out all affected
- * locks and tasks (and only those tasks)
- */
- struct mutex {
- atomic_long_t owner;
- raw_spinlock_t wait_lock;
- #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
- struct optimistic_spin_queue osq; /* Spinner MCS lock */
- #endif
- struct list_head wait_list;
- #ifdef CONFIG_DEBUG_MUTEXES
- void *magic;
- #endif
- #ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
- #endif
- ANDROID_OEM_DATA_ARRAY(1, 2);
- };
- #ifdef CONFIG_DEBUG_MUTEXES
- #define __DEBUG_MUTEX_INITIALIZER(lockname) \
- , .magic = &lockname
- extern void mutex_destroy(struct mutex *lock);
- #else
- # define __DEBUG_MUTEX_INITIALIZER(lockname)
- static inline void mutex_destroy(struct mutex *lock) {}
- #endif
- /**
- * 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) \
- do { \
- static struct lock_class_key __key; \
- \
- __mutex_init((mutex), #mutex, &__key); \
- } while (0)
- #define __MUTEX_INITIALIZER(lockname) \
- { .owner = ATOMIC_LONG_INIT(0) \
- , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
- , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
- __DEBUG_MUTEX_INITIALIZER(lockname) \
- __DEP_MAP_MUTEX_INITIALIZER(lockname) }
- #define DEFINE_MUTEX(mutexname) \
- struct mutex mutexname = __MUTEX_INITIALIZER(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.
- */
- #include <linux/rtmutex.h>
- struct mutex {
- struct rt_mutex_base rtmutex;
- #ifdef CONFIG_DEBUG_LOCK_ALLOC
- struct lockdep_map dep_map;
- #endif
- };
- #define __MUTEX_INITIALIZER(mutexname) \
- { \
- .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \
- __DEP_MAP_MUTEX_INITIALIZER(mutexname) \
- }
- #define DEFINE_MUTEX(mutexname) \
- struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
- extern void __mutex_rt_init(struct mutex *lock, const char *name,
- struct lock_class_key *key);
- extern int mutex_trylock(struct mutex *lock);
- static inline void mutex_destroy(struct mutex *lock) { }
- #define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex)
- #define __mutex_init(mutex, name, key) \
- do { \
- rt_mutex_base_init(&(mutex)->rtmutex); \
- __mutex_rt_init((mutex), name, key); \
- } while (0)
- #define mutex_init(mutex) \
- do { \
- static struct lock_class_key __key; \
- \
- __mutex_init((mutex), #mutex, &__key); \
- } while (0)
- #endif /* CONFIG_PREEMPT_RT */
- /*
- * 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) mutex_lock_nested(lock, 0)
- #define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0)
- #define mutex_lock_killable(lock) mutex_lock_killable_nested(lock, 0)
- #define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0)
- #define mutex_lock_nest_lock(lock, nest_lock) \
- do { \
- typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
- _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \
- } while (0)
- #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(lock, subclass) mutex_lock(lock)
- # define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock)
- # define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock)
- # define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
- # define mutex_lock_io_nested(lock, subclass) mutex_lock_io(lock)
- #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);
- #endif /* __LINUX_MUTEX_H */
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