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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 * @waiters_leftmost: top waiter
27 * @owner: the mutex owner
28 */
29struct rt_mutex {
30 raw_spinlock_t wait_lock;
31 struct rb_root waiters;
32 struct rb_node *waiters_leftmost;
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 \
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
109extern void rt_mutex_lock(struct rt_mutex *lock);
110extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
111extern int rt_mutex_timed_lock(struct rt_mutex *lock,
112 struct hrtimer_sleeper *timeout);
113
114extern int rt_mutex_trylock(struct rt_mutex *lock);
115
116extern void rt_mutex_unlock(struct rt_mutex *lock);
117
118#endif