sched: Disable scheduler warnings during oopses
[linux-2.6.git] / kernel / rtmutex_common.h
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
25 extern 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  */
47 struct 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 #ifdef CONFIG_DEBUG_RT_MUTEXES
53         unsigned long           ip;
54         struct pid              *deadlock_task_pid;
55         struct rt_mutex         *deadlock_lock;
56 #endif
57 };
58
59 /*
60  * Various helpers to access the waiters-plist:
61  */
62 static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
63 {
64         return !plist_head_empty(&lock->wait_list);
65 }
66
67 static inline struct rt_mutex_waiter *
68 rt_mutex_top_waiter(struct rt_mutex *lock)
69 {
70         struct rt_mutex_waiter *w;
71
72         w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
73                                list_entry);
74         BUG_ON(w->lock != lock);
75
76         return w;
77 }
78
79 static inline int task_has_pi_waiters(struct task_struct *p)
80 {
81         return !plist_head_empty(&p->pi_waiters);
82 }
83
84 static inline struct rt_mutex_waiter *
85 task_top_pi_waiter(struct task_struct *p)
86 {
87         return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
88                                   pi_list_entry);
89 }
90
91 /*
92  * lock->owner state tracking:
93  */
94 #define RT_MUTEX_HAS_WAITERS    1UL
95 #define RT_MUTEX_OWNER_MASKALL  1UL
96
97 static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
98 {
99         return (struct task_struct *)
100                 ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
101 }
102
103 /*
104  * PI-futex support (proxy locking functions, etc.):
105  */
106 extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
107 extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
108                                        struct task_struct *proxy_owner);
109 extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
110                                   struct task_struct *proxy_owner);
111 extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
112                                      struct rt_mutex_waiter *waiter,
113                                      struct task_struct *task,
114                                      int detect_deadlock);
115 extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
116                                       struct hrtimer_sleeper *to,
117                                       struct rt_mutex_waiter *waiter,
118                                       int detect_deadlock);
119
120 #ifdef CONFIG_DEBUG_RT_MUTEXES
121 # include "rtmutex-debug.h"
122 #else
123 # include "rtmutex.h"
124 #endif
125
126 #endif