2 * RT Mutexes: blocking mutual exclusion locks with PI support
4 * started by Ingo Molnar and Thomas Gleixner:
6 * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
7 * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
9 * This file contains the private data structure and API definitions.
12 #ifndef __KERNEL_RTMUTEX_COMMON_H
13 #define __KERNEL_RTMUTEX_COMMON_H
15 #include <linux/rtmutex.h>
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.
23 #ifdef CONFIG_RT_MUTEX_TESTER
25 extern void schedule_rt_mutex_test(struct rt_mutex
*lock
);
27 #define schedule_rt_mutex(_lock) \
29 if (!(current->flags & PF_MUTEX_TESTER)) \
32 schedule_rt_mutex_test(_lock); \
36 # define schedule_rt_mutex(_lock) schedule()
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.
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
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
54 struct pid
*deadlock_task_pid
;
55 struct rt_mutex
*deadlock_lock
;
60 * Various helpers to access the waiters-plist:
62 static inline int rt_mutex_has_waiters(struct rt_mutex
*lock
)
64 return !plist_head_empty(&lock
->wait_list
);
67 static inline struct rt_mutex_waiter
*
68 rt_mutex_top_waiter(struct rt_mutex
*lock
)
70 struct rt_mutex_waiter
*w
;
72 w
= plist_first_entry(&lock
->wait_list
, struct rt_mutex_waiter
,
74 BUG_ON(w
->lock
!= lock
);
79 static inline int task_has_pi_waiters(struct task_struct
*p
)
81 return !plist_head_empty(&p
->pi_waiters
);
84 static inline struct rt_mutex_waiter
*
85 task_top_pi_waiter(struct task_struct
*p
)
87 return plist_first_entry(&p
->pi_waiters
, struct rt_mutex_waiter
,
92 * lock->owner state tracking:
94 #define RT_MUTEX_OWNER_PENDING 1UL
95 #define RT_MUTEX_HAS_WAITERS 2UL
96 #define RT_MUTEX_OWNER_MASKALL 3UL
98 static inline struct task_struct
*rt_mutex_owner(struct rt_mutex
*lock
)
100 return (struct task_struct
*)
101 ((unsigned long)lock
->owner
& ~RT_MUTEX_OWNER_MASKALL
);
104 static inline struct task_struct
*rt_mutex_real_owner(struct rt_mutex
*lock
)
106 return (struct task_struct
*)
107 ((unsigned long)lock
->owner
& ~RT_MUTEX_HAS_WAITERS
);
110 static inline unsigned long rt_mutex_owner_pending(struct rt_mutex
*lock
)
112 return (unsigned long)lock
->owner
& RT_MUTEX_OWNER_PENDING
;
116 * PI-futex support (proxy locking functions, etc.):
118 extern struct task_struct
*rt_mutex_next_owner(struct rt_mutex
*lock
);
119 extern void rt_mutex_init_proxy_locked(struct rt_mutex
*lock
,
120 struct task_struct
*proxy_owner
);
121 extern void rt_mutex_proxy_unlock(struct rt_mutex
*lock
,
122 struct task_struct
*proxy_owner
);
123 extern int rt_mutex_start_proxy_lock(struct rt_mutex
*lock
,
124 struct rt_mutex_waiter
*waiter
,
125 struct task_struct
*task
,
126 int detect_deadlock
);
127 extern int rt_mutex_finish_proxy_lock(struct rt_mutex
*lock
,
128 struct hrtimer_sleeper
*to
,
129 struct rt_mutex_waiter
*waiter
,
130 int detect_deadlock
);
132 #ifdef CONFIG_DEBUG_RT_MUTEXES
133 # include "rtmutex-debug.h"
135 # include "rtmutex.h"
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