Linux/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
127 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us