LXR linux/include/linux/rtmutex.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * RT Mutexes: blocking mutual exclusion locks with PI support
   4 *
   5 * started by Ingo Molnar and Thomas Gleixner:
   6 *
   7 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   8 *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
   9 *
  10 * This file contains the public data structure and API definitions.
  11 */
  12
  13#ifndef __LINUX_RT_MUTEX_H
  14#define __LINUX_RT_MUTEX_H
  15
  16#include <linux/linkage.h>
  17#include <linux/rbtree.h>
  18#include <linux/spinlock_types.h>
  19
  20extern int max_lock_depth; /* for sysctl */
  21
  22/**
  23 * The rt_mutex structure
  24 *
  25 * @wait_lock:  spinlock to protect the structure
  26 * @waiters:    rbtree root to enqueue waiters in priority order;
  27 *              caches top-waiter (leftmost node).
  28 * @owner:      the mutex owner
  29 */
  30struct rt_mutex {
  31        raw_spinlock_t          wait_lock;
  32        struct rb_root_cached   waiters;
  33        struct task_struct      *owner;
  34#ifdef CONFIG_DEBUG_RT_MUTEXES
  35        int                     save_state;
  36        const char              *name, *file;
  37        int                     line;
  38        void                    *magic;
  39#endif
  40#ifdef CONFIG_DEBUG_LOCK_ALLOC
  41        struct lockdep_map      dep_map;
  42#endif
  43};
  44
  45struct rt_mutex_waiter;
  46struct hrtimer_sleeper;
  47
  48#ifdef CONFIG_DEBUG_RT_MUTEXES
  49 extern int rt_mutex_debug_check_no_locks_freed(const void *from,
  50                                                unsigned long len);
  51 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
  52#else
  53 static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
  54                                                       unsigned long len)
  55 {
  56        return 0;
  57 }
  58# define rt_mutex_debug_check_no_locks_held(task)       do { } while (0)
  59#endif
  60
  61#ifdef CONFIG_DEBUG_RT_MUTEXES
  62# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
  63        , .name = #mutexname, .file = __FILE__, .line = __LINE__
  64
  65# define rt_mutex_init(mutex) \
  66do { \
  67        static struct lock_class_key __key; \
  68        __rt_mutex_init(mutex, __func__, &__key); \
  69} while (0)
  70
  71 extern void rt_mutex_debug_task_free(struct task_struct *tsk);
  72#else
  73# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
  74# define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, NULL, NULL)
  75# define rt_mutex_debug_task_free(t)                    do { } while (0)
  76#endif
  77
  78#ifdef CONFIG_DEBUG_LOCK_ALLOC
  79#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
  80        , .dep_map = { .name = #mutexname }
  81#else
  82#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
  83#endif
  84
  85#define __RT_MUTEX_INITIALIZER(mutexname) \
  86        { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
  87        , .waiters = RB_ROOT_CACHED \
  88        , .owner = NULL \
  89        __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
  90        __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
  91
  92#define DEFINE_RT_MUTEX(mutexname) \
  93        struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
  94
  95/**
  96 * rt_mutex_is_locked - is the mutex locked
  97 * @lock: the mutex to be queried
  98 *
  99 * Returns 1 if the mutex is locked, 0 if unlocked.
 100 */
 101static inline int rt_mutex_is_locked(struct rt_mutex *lock)
 102{
 103        return lock->owner != NULL;
 104}
 105
 106extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
 107extern void rt_mutex_destroy(struct rt_mutex *lock);
 108
 109#ifdef CONFIG_DEBUG_LOCK_ALLOC
 110extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
 111#define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
 112#else
 113extern void rt_mutex_lock(struct rt_mutex *lock);
 114#define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
 115#endif
 116
 117extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
 118extern int rt_mutex_timed_lock(struct rt_mutex *lock,
 119                               struct hrtimer_sleeper *timeout);
 120
 121extern int rt_mutex_trylock(struct rt_mutex *lock);
 122
 123extern void rt_mutex_unlock(struct rt_mutex *lock);
 124
 125#endif
 126