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Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001/*
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/*
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070018 * 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 *
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010021 * @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
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070023 * @task: task reference to the blocked task
24 */
25struct rt_mutex_waiter {
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010026 struct rb_node tree_entry;
27 struct rb_node pi_tree_entry;
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070028 struct task_struct *task;
29 struct rt_mutex *lock;
30#ifdef CONFIG_DEBUG_RT_MUTEXES
31 unsigned long ip;
Pavel Emelyanov48d13e42008-02-08 04:21:53 -080032 struct pid *deadlock_task_pid;
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070033 struct rt_mutex *deadlock_lock;
34#endif
Dario Faggioli2d3d8912013-11-07 14:43:44 +010035 int prio;
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070036};
37
38/*
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010039 * Various helpers to access the waiters-tree:
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070040 */
41static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
42{
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010043 return !RB_EMPTY_ROOT(&lock->waiters);
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070044}
45
46static inline struct rt_mutex_waiter *
47rt_mutex_top_waiter(struct rt_mutex *lock)
48{
49 struct rt_mutex_waiter *w;
50
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010051 w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
52 tree_entry);
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070053 BUG_ON(w->lock != lock);
54
55 return w;
56}
57
58static inline int task_has_pi_waiters(struct task_struct *p)
59{
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010060 return !RB_EMPTY_ROOT(&p->pi_waiters);
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070061}
62
63static inline struct rt_mutex_waiter *
64task_top_pi_waiter(struct task_struct *p)
65{
Peter Zijlstrafb00aca2013-11-07 14:43:43 +010066 return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
67 pi_tree_entry);
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070068}
69
70/*
71 * lock->owner state tracking:
72 */
Lai Jiangshan81612392011-01-14 17:09:41 +080073#define RT_MUTEX_HAS_WAITERS 1UL
74#define RT_MUTEX_OWNER_MASKALL 1UL
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070075
76static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
77{
Thomas Gleixner1be5d4f2016-11-30 21:04:42 +000078 unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
79
80 return (struct task_struct *) (owner & ~RT_MUTEX_OWNER_MASKALL);
Ingo Molnar23f78d4a2006-06-27 02:54:53 -070081}
82
Ingo Molnarc87e2832006-06-27 02:54:58 -070083/*
Thomas Gleixner8930ed82014-05-22 03:25:47 +000084 * Constants for rt mutex functions which have a selectable deadlock
85 * detection.
86 *
87 * RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
88 * no further PI adjustments to be made.
89 *
90 * RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
91 * walk of the lock chain.
92 */
93enum rtmutex_chainwalk {
94 RT_MUTEX_MIN_CHAINWALK,
95 RT_MUTEX_FULL_CHAINWALK,
96};
97
98/*
Ingo Molnarc87e2832006-06-27 02:54:58 -070099 * PI-futex support (proxy locking functions, etc.):
100 */
101extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
102extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
103 struct task_struct *proxy_owner);
104extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
105 struct task_struct *proxy_owner);
Darren Hart8dac4562009-04-03 13:40:12 -0700106extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
107 struct rt_mutex_waiter *waiter,
Thomas Gleixnerc051b212014-05-22 03:25:50 +0000108 struct task_struct *task);
Darren Hart8dac4562009-04-03 13:40:12 -0700109extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
110 struct hrtimer_sleeper *to,
Thomas Gleixnerc051b212014-05-22 03:25:50 +0000111 struct rt_mutex_waiter *waiter);
112extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
Sebastian Andrzej Siewior802ab582015-06-17 10:33:50 +0200113extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
114 struct wake_q_head *wqh);
115extern void rt_mutex_adjust_prio(struct task_struct *task);
Thomas Gleixner36cf3b52007-07-15 23:41:20 -0700116
117#ifdef CONFIG_DEBUG_RT_MUTEXES
118# include "rtmutex-debug.h"
119#else
120# include "rtmutex.h"
121#endif
122
Ingo Molnar23f78d4a2006-06-27 02:54:53 -0700123#endif