Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -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 | /* |
Thomas Gleixner | 61a8712 | 2006-06-27 02:54:56 -0700 | [diff] [blame] | 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 | /* |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 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 | pid_t 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_OWNER_PENDING 1UL |
| 95 | #define RT_MUTEX_HAS_WAITERS 2UL |
| 96 | #define RT_MUTEX_OWNER_MASKALL 3UL |
| 97 | |
| 98 | static 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 | static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock) |
| 105 | { |
Thomas Gleixner | 36cf3b5 | 2007-07-15 23:41:20 -0700 | [diff] [blame] | 106 | return (struct task_struct *) |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 107 | ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); |
| 108 | } |
| 109 | |
| 110 | static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock) |
| 111 | { |
| 112 | return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING; |
| 113 | } |
| 114 | |
Ingo Molnar | c87e283 | 2006-06-27 02:54:58 -0700 | [diff] [blame] | 115 | /* |
| 116 | * PI-futex support (proxy locking functions, etc.): |
| 117 | */ |
| 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); |
Thomas Gleixner | 36cf3b5 | 2007-07-15 23:41:20 -0700 | [diff] [blame] | 123 | |
| 124 | #ifdef CONFIG_DEBUG_RT_MUTEXES |
| 125 | # include "rtmutex-debug.h" |
| 126 | #else |
| 127 | # include "rtmutex.h" |
| 128 | #endif |
| 129 | |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 130 | #endif |