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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 private data structure and API definitions.
10 */
11
12#ifndef __KERNEL_RTMUTEX_COMMON_H
13#define __KERNEL_RTMUTEX_COMMON_H
14
15#include <linux/rtmutex.h>
16
17/*
18 * The rtmutex in kernel tester is independent of rtmutex debugging. We
19 * call schedule_rt_mutex_test() instead of schedule() for the tasks which
20 * belong to the tester. That way we can delay the wakeup path of those
21 * threads to provoke lock stealing and testing of complex boosting scenarios.
22 */
23#ifdef CONFIG_RT_MUTEX_TESTER
24
25extern void schedule_rt_mutex_test(struct rt_mutex *lock);
26
27#define schedule_rt_mutex(_lock) \
28 do { \
29 if (!(current->flags & PF_MUTEX_TESTER)) \
30 schedule(); \
31 else \
32 schedule_rt_mutex_test(_lock); \
33 } while (0)
34
35#else
36# define schedule_rt_mutex(_lock) schedule()
37#endif
38
39/*
40 * This is the control structure for tasks blocked on a rt_mutex,
41 * which is allocated on the kernel stack on of the blocked task.
42 *
43 * @tree_entry: pi node to enqueue into the mutex waiters tree
44 * @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree
45 * @task: task reference to the blocked task
46 */
47struct rt_mutex_waiter {
48 struct rb_node tree_entry;
49 struct rb_node pi_tree_entry;
50 struct task_struct *task;
51 struct rt_mutex *lock;
52#ifdef CONFIG_DEBUG_RT_MUTEXES
53 unsigned long ip;
54 struct pid *deadlock_task_pid;
55 struct rt_mutex *deadlock_lock;
56#endif
57 int prio;
58};
59
60/*
61 * Various helpers to access the waiters-tree:
62 */
63static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
64{
65 return !RB_EMPTY_ROOT(&lock->waiters);
66}
67
68static inline struct rt_mutex_waiter *
69rt_mutex_top_waiter(struct rt_mutex *lock)
70{
71 struct rt_mutex_waiter *w;
72
73 w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
74 tree_entry);
75 BUG_ON(w->lock != lock);
76
77 return w;
78}
79
80static inline int task_has_pi_waiters(struct task_struct *p)
81{
82 return !RB_EMPTY_ROOT(&p->pi_waiters);
83}
84
85static inline struct rt_mutex_waiter *
86task_top_pi_waiter(struct task_struct *p)
87{
88 return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
89 pi_tree_entry);
90}
91
92/*
93 * lock->owner state tracking:
94 */
95#define RT_MUTEX_HAS_WAITERS 1UL
96#define RT_MUTEX_OWNER_MASKALL 1UL
97
98static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
99{
100 return (struct task_struct *)
101 ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
102}
103
104/*
105 * PI-futex support (proxy locking functions, etc.):
106 */
107extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
108extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
109 struct task_struct *proxy_owner);
110extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
111 struct task_struct *proxy_owner);
112extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
113 struct rt_mutex_waiter *waiter,
114 struct task_struct *task,
115 int detect_deadlock);
116extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
117 struct hrtimer_sleeper *to,
118 struct rt_mutex_waiter *waiter,
119 int detect_deadlock);
120
121#ifdef CONFIG_DEBUG_RT_MUTEXES
122# include "rtmutex-debug.h"
123#else
124# include "rtmutex.h"
125#endif
126
127#endif
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 private data structure and API definitions.
10 */
11
12#ifndef __KERNEL_RTMUTEX_COMMON_H
13#define __KERNEL_RTMUTEX_COMMON_H
14
15#include <linux/rtmutex.h>
16
17/*
18 * This is the control structure for tasks blocked on a rt_mutex,
19 * which is allocated on the kernel stack on of the blocked task.
20 *
21 * @tree_entry: pi node to enqueue into the mutex waiters tree
22 * @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree
23 * @task: task reference to the blocked task
24 */
25struct rt_mutex_waiter {
26 struct rb_node tree_entry;
27 struct rb_node pi_tree_entry;
28 struct task_struct *task;
29 struct rt_mutex *lock;
30#ifdef CONFIG_DEBUG_RT_MUTEXES
31 unsigned long ip;
32 struct pid *deadlock_task_pid;
33 struct rt_mutex *deadlock_lock;
34#endif
35 int prio;
36};
37
38/*
39 * Various helpers to access the waiters-tree:
40 */
41static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
42{
43 return !RB_EMPTY_ROOT(&lock->waiters);
44}
45
46static inline struct rt_mutex_waiter *
47rt_mutex_top_waiter(struct rt_mutex *lock)
48{
49 struct rt_mutex_waiter *w;
50
51 w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
52 tree_entry);
53 BUG_ON(w->lock != lock);
54
55 return w;
56}
57
58static inline int task_has_pi_waiters(struct task_struct *p)
59{
60 return !RB_EMPTY_ROOT(&p->pi_waiters);
61}
62
63static inline struct rt_mutex_waiter *
64task_top_pi_waiter(struct task_struct *p)
65{
66 return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
67 pi_tree_entry);
68}
69
70/*
71 * lock->owner state tracking:
72 */
73#define RT_MUTEX_HAS_WAITERS 1UL
74#define RT_MUTEX_OWNER_MASKALL 1UL
75
76static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
77{
78 return (struct task_struct *)
79 ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
80}
81
82/*
83 * Constants for rt mutex functions which have a selectable deadlock
84 * detection.
85 *
86 * RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
87 * no further PI adjustments to be made.
88 *
89 * RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
90 * walk of the lock chain.
91 */
92enum rtmutex_chainwalk {
93 RT_MUTEX_MIN_CHAINWALK,
94 RT_MUTEX_FULL_CHAINWALK,
95};
96
97/*
98 * PI-futex support (proxy locking functions, etc.):
99 */
100extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
101extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
102 struct task_struct *proxy_owner);
103extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
104 struct task_struct *proxy_owner);
105extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
106 struct rt_mutex_waiter *waiter,
107 struct task_struct *task);
108extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
109 struct hrtimer_sleeper *to,
110 struct rt_mutex_waiter *waiter);
111extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
112extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
113 struct wake_q_head *wqh);
114extern void rt_mutex_adjust_prio(struct task_struct *task);
115
116#ifdef CONFIG_DEBUG_RT_MUTEXES
117# include "rtmutex-debug.h"
118#else
119# include "rtmutex.h"
120#endif
121
122#endif