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