diff options
Diffstat (limited to 'include/linux/mutex.h')
| -rw-r--r-- | include/linux/mutex.h | 255 |
1 files changed, 166 insertions, 89 deletions
diff --git a/include/linux/mutex.h b/include/linux/mutex.h index ccd4260834c5..bf535f0118bb 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * Mutexes: blocking mutual exclusion locks * @@ -13,75 +14,41 @@ #include <asm/current.h> #include <linux/list.h> #include <linux/spinlock_types.h> -#include <linux/linkage.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; -/* - * 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 { - /* 1: unlocked, 0: locked, negative: locked, possible waiters */ - atomic_t count; - spinlock_t wait_lock; - struct list_head wait_list; -#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) - struct task_struct *owner; -#endif -#ifdef CONFIG_MUTEX_SPIN_ON_OWNER - void *spin_mlock; /* Spinner MCS lock */ -#endif -#ifdef CONFIG_DEBUG_MUTEXES - const char *name; - void *magic; -#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map dep_map; +# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ + , .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_SLEEP, \ + } +#else +# define __DEP_MAP_MUTEX_INITIALIZER(lockname) #endif -}; -/* - * This is the control structure for tasks blocked on mutex, - * which resides on the blocked task's kernel stack: - */ -struct mutex_waiter { - struct list_head list; - struct task_struct *task; #ifdef CONFIG_DEBUG_MUTEXES - void *magic; -#endif -}; -#ifdef CONFIG_DEBUG_MUTEXES -# include <linux/mutex-debug.h> +# 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 @@ -90,25 +57,28 @@ struct mutex_waiter { * * 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); \ +#define mutex_init(mutex) \ +do { \ + static struct lock_class_key __key; \ + \ + __mutex_init((mutex), #mutex, &__key); \ } while (0) -static inline void mutex_destroy(struct mutex *lock) {} -#endif -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ - , .dep_map = { .name = #lockname } -#else -# define __DEP_MAP_MUTEX_INITIALIZER(lockname) -#endif +/** + * mutex_init_with_key - initialize a mutex with a given lockdep key + * @mutex: the mutex to be initialized + * @key: the lockdep key to be associated with the mutex + * + * Initialize the mutex to the unlocked state. + * + * It is not allowed to initialize an already locked mutex. + */ +#define mutex_init_with_key(mutex, key) __mutex_init((mutex), #mutex, (key)) +#ifndef CONFIG_PREEMPT_RT #define __MUTEX_INITIALIZER(lockname) \ - { .count = ATOMIC_INIT(1) \ - , .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ + { .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) } @@ -116,36 +86,114 @@ static inline void mutex_destroy(struct mutex *lock) {} #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); +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void mutex_init_lockep(struct mutex *lock, const char *name, struct lock_class_key *key); + +static inline void __mutex_init(struct mutex *lock, const char *name, + struct lock_class_key *key) +{ + mutex_init_lockep(lock, name, key); +} +#else +extern void mutex_init_generic(struct mutex *lock); + +static inline void __mutex_init(struct mutex *lock, const char *name, + struct lock_class_key *key) +{ + mutex_init_generic(lock); +} +#endif /* !CONFIG_DEBUG_LOCK_ALLOC */ /** * mutex_is_locked - is the mutex locked * @lock: the mutex to be queried * - * Returns 1 if the mutex is locked, 0 if unlocked. + * 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. */ -static inline int mutex_is_locked(struct mutex *lock) + +#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) + +#define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern void mutex_rt_init_lockdep(struct mutex *mutex, const char *name, + struct lock_class_key *key); + +static inline void __mutex_init(struct mutex *lock, const char *name, + struct lock_class_key *key) +{ + mutex_rt_init_lockdep(lock, name, key); +} + +#else +extern void mutex_rt_init_generic(struct mutex *mutex); + +static inline void __mutex_init(struct mutex *lock, const char *name, + struct lock_class_key *key) { - return atomic_read(&lock->count) != 1; + mutex_rt_init_generic(lock); } +#endif /* !CONFIG_LOCKDEP */ +#endif /* CONFIG_PREEMPT_RT */ + +#ifdef CONFIG_DEBUG_MUTEXES + +int __must_check __devm_mutex_init(struct device *dev, struct mutex *lock); + +#else + +static inline int __must_check __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 __mutex_init_ret(mutex) \ +({ \ + typeof(mutex) mutex_ = (mutex); \ + \ + mutex_init(mutex_); \ + mutex_; \ +}) + +#define devm_mutex_init(dev, mutex) \ + __devm_mutex_init(dev, __mutex_init_ret(mutex)) /* - * See kernel/mutex.c for detailed documentation of these APIs. - * Also see Documentation/mutex-design.txt. + * 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 int __must_check _mutex_lock_killable(struct mutex *lock, + unsigned int subclass, struct lockdep_map *nest_lock); +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_killable(lock) _mutex_lock_killable(lock, 0, NULL) +#define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0) #define mutex_lock_nest_lock(lock, nest_lock) \ do { \ @@ -153,15 +201,27 @@ do { \ _mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \ } while (0) +#define mutex_lock_killable_nest_lock(lock, nest_lock) \ +( \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map), \ + _mutex_lock_killable(lock, 0, &(nest_lock)->dep_map) \ +) + +#define mutex_lock_killable_nested(lock, subclass) \ + _mutex_lock_killable(lock, subclass, NULL) + #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_killable_nest_lock(lock, nest_lock) 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 /* @@ -170,13 +230,30 @@ extern int __must_check mutex_lock_killable(struct mutex *lock); * * Returns 1 if the mutex has been acquired successfully, and 0 on contention. */ + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern int _mutex_trylock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock); + +#define mutex_trylock_nest_lock(lock, nest_lock) \ +( \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map), \ + _mutex_trylock_nest_lock(lock, &(nest_lock)->dep_map) \ +) + +#define mutex_trylock(lock) _mutex_trylock_nest_lock(lock, NULL) +#else extern int mutex_trylock(struct mutex *lock); +#define mutex_trylock_nest_lock(lock, nest_lock) mutex_trylock(lock) +#endif + extern void mutex_unlock(struct mutex *lock); extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); -#ifndef CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX -#define arch_mutex_cpu_relax() cpu_relax() -#endif +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), _RET == 0) -#endif +extern unsigned long mutex_get_owner(struct mutex *lock); + +#endif /* __LINUX_MUTEX_H */ |