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/plist.h>
17 #include <linux/spinlock_types.h>
18
19 /**
20 * The rt_mutex structure
21 *
22 * @wait_lock: spinlock to protect the structure
23 * @wait_list: pilist head to enqueue waiters in priority order
24 * @owner: the mutex owner
25 */
26 struct rt_mutex {
27 spinlock_t wait_lock;
28 struct plist_head wait_list;
29 struct task_struct *owner;
30 #ifdef CONFIG_DEBUG_RT_MUTEXES
31 int save_state;
32 const char *name, *file;
33 int line;
34 void *magic;
35 #endif
36 };
37
38 struct rt_mutex_waiter;
39 struct hrtimer_sleeper;
40
41 #ifdef CONFIG_DEBUG_RT_MUTEXES
42 extern int rt_mutex_debug_check_no_locks_freed(const void *from,
43 unsigned long len);
44 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
45 #else
46 static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
47 unsigned long len)
48 {
49 return 0;
50 }
51 # define rt_mutex_debug_check_no_locks_held(task) do { } while (0)
52 #endif
53
54 #ifdef CONFIG_DEBUG_RT_MUTEXES
55 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
56 , .name = #mutexname, .file = __FILE__, .line = __LINE__
57 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, __func__)
58 extern void rt_mutex_debug_task_free(struct task_struct *tsk);
59 #else
60 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
61 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL)
62 # define rt_mutex_debug_task_free(t) do { } while (0)
63 #endif
64
65 #define __RT_MUTEX_INITIALIZER(mutexname) \
66 { .wait_lock = __SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
67 , .wait_list = PLIST_HEAD_INIT(mutexname.wait_list, mutexname.wait_lock) \
68 , .owner = NULL \
69 __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
70
71 #define DEFINE_RT_MUTEX(mutexname) \
72 struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
73
74 /**
75 * rt_mutex_is_locked - is the mutex locked
76 * @lock: the mutex to be queried
77 *
78 * Returns 1 if the mutex is locked, 0 if unlocked.
79 */
80 static inline int rt_mutex_is_locked(struct rt_mutex *lock)
81 {
82 return lock->owner != NULL;
83 }
84
85 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
86 extern void rt_mutex_destroy(struct rt_mutex *lock);
87
88 extern void rt_mutex_lock(struct rt_mutex *lock);
89 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
90 int detect_deadlock);
91 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
92 struct hrtimer_sleeper *timeout,
93 int detect_deadlock);
94
95 extern int rt_mutex_trylock(struct rt_mutex *lock);
96
97 extern void rt_mutex_unlock(struct rt_mutex *lock);
98
99 #ifdef CONFIG_RT_MUTEXES
100 # define INIT_RT_MUTEXES(tsk) \
101 .pi_waiters = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
102 INIT_RT_MUTEX_DEBUG(tsk)
103 #else
104 # define INIT_RT_MUTEXES(tsk)
105 #endif
106
107 #endif
108
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