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#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 */ 62static inline int rt_mutex_has_waiters(struct rt_mutex *lock) 63{ 64 return !plist_head_empty(&lock->wait_list); 65} 66 67static inline struct rt_mutex_waiter * 68rt_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 79static inline int task_has_pi_waiters(struct task_struct *p) 80{ 81 return !plist_head_empty(&p->pi_waiters); 82} 83 84static inline struct rt_mutex_waiter * 85task_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 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 104static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock) 105{ 106 return (struct task_struct *) 107 ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); 108} 109 110static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock) 111{ 112 return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING; 113} 114 115/* 116 * PI-futex support (proxy locking functions, etc.): 117 */ 118extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock); 119extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock, 120 struct task_struct *proxy_owner); 121extern void rt_mutex_proxy_unlock(struct rt_mutex *lock, 122 struct task_struct *proxy_owner); 123extern 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); 127extern 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); 131 132#ifdef CONFIG_DEBUG_RT_MUTEXES 133# include "rtmutex-debug.h" 134#else 135# include "rtmutex.h" 136#endif 137 138#endif 139