Gitiles
Code Review Sign In
192.168.1.100 / T106_DC / 2a66deef0a76643e51caf235f80a0a872e8d5caf / . / ap / os / linux / linux-3.4.x / kernel / rtmutex_common.h
blob: 213c7bf3c0d95befee8696d6d2e6be785c3b4200 [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -0700[diff] [blame]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 * @list_entry: pi node to enqueue into the mutex waiters list
44 * @pi_list_entry: pi node to enqueue into the mutex owner waiters list
45 * @task: task reference to the blocked task
46 */
47struct rt_mutex_waiter {
48 struct plist_node list_entry;
49 struct plist_node pi_list_entry;
50 struct task_struct *task;
51 struct rt_mutex *lock;
52 bool savestate;
53#ifdef CONFIG_DEBUG_RT_MUTEXES
54 unsigned long ip;
55 struct pid *deadlock_task_pid;
56 struct rt_mutex *deadlock_lock;
57#endif
58};
59
60/*
61 * Various helpers to access the waiters-plist:
62 */
63static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
64{
65 return !plist_head_empty(&lock->wait_list);
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 = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
74 list_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 !plist_head_empty(&p->pi_waiters);
83}
84
85static inline struct rt_mutex_waiter *
86task_top_pi_waiter(struct task_struct *p)
87{
88 return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
89 pi_list_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 * Constants for rt mutex functions which have a selectable deadlock
106 * detection.
107 *
108 * RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
109 * no further PI adjustments to be made.
110 *
111 * RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
112 * walk of the lock chain.
113 */
114enum rtmutex_chainwalk {
115 RT_MUTEX_MIN_CHAINWALK,
116 RT_MUTEX_FULL_CHAINWALK,
117};
118
119/*
120 * PI-futex support (proxy locking functions, etc.):
121 */
122#define PI_WAKEUP_INPROGRESS ((struct rt_mutex_waiter *) 1)
123#define PI_REQUEUE_INPROGRESS ((struct rt_mutex_waiter *) 2)
124
125extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
126extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
127 struct task_struct *proxy_owner);
128extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
129 struct task_struct *proxy_owner);
130extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
131 struct rt_mutex_waiter *waiter,
132 struct task_struct *task);
133extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
134 struct hrtimer_sleeper *to,
135 struct rt_mutex_waiter *waiter);
136extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
137
138#ifdef CONFIG_DEBUG_RT_MUTEXES
139# include "rtmutex-debug.h"
140#else
141# include "rtmutex.h"
142#endif
143
144static inline void
145rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
146{
147 debug_rt_mutex_init_waiter(waiter);
148 waiter->task = NULL;
149 waiter->savestate = savestate;
150}
151
152#endif