include/linux/rtmutex.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 public data structure and API definitions.
  10  */
  11
  12 #ifndef __LINUX_RT_MUTEX_H
  13 #define __LINUX_RT_MUTEX_H
  14
  15 #include <linux/linkage.h>
  16 #include <linux/plist.h>
  17 #include <linux/spinlock_types.h>
  18
  19 /**
  20  * The rt_mutex structure
  21  *
  22  * @wait_lock:  spinlock to protect the structure
  23  * @wait_list:  pilist head to enqueue waiters in priority order
  24  * @owner:      the mutex owner
  25  */
  26 struct rt_mutex {
  27         spinlock_t              wait_lock;
  28         struct plist_head       wait_list;
  29         struct task_struct      *owner;
  30 #ifdef CONFIG_DEBUG_RT_MUTEXES
  31         int                     save_state;
  32         const char              *name, *file;
  33         int                     line;
  34         void                    *magic;
  35 #endif
  36 };
  37
  38 struct rt_mutex_waiter;
  39 struct hrtimer_sleeper;
  40
  41 #ifdef CONFIG_DEBUG_RT_MUTEXES
  42  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
  43                                                 unsigned long len);
  44  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
  45 #else
  46  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
  47                                                        unsigned long len)
  48  {
  49         return 0;
  50  }
  51 # define rt_mutex_debug_check_no_locks_held(task)       do { } while (0)
  52 #endif
  53
  54 #ifdef CONFIG_DEBUG_RT_MUTEXES
  55 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
  56         , .name = #mutexname, .file = __FILE__, .line = __LINE__
  57 # define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, __func__)
  58  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
  59 #else
  60 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
  61 # define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, NULL)
  62 # define rt_mutex_debug_task_free(t)                    do { } while (0)
  63 #endif
  64
  65 #define __RT_MUTEX_INITIALIZER(mutexname) \
  66         { .wait_lock = __SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
  67         , .wait_list = PLIST_HEAD_INIT(mutexname.wait_list, mutexname.wait_lock) \
  68         , .owner = NULL \
  69         __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
  70
  71 #define DEFINE_RT_MUTEX(mutexname) \
  72         struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
  73
  74 /**
  75  * rt_mutex_is_locked - is the mutex locked
  76  * @lock: the mutex to be queried
  77  *
  78  * Returns 1 if the mutex is locked, 0 if unlocked.
  79  */
  80 static inline int rt_mutex_is_locked(struct rt_mutex *lock)
  81 {
  82         return lock->owner != NULL;
  83 }
  84
  85 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
  86 extern void rt_mutex_destroy(struct rt_mutex *lock);
  87
  88 extern void rt_mutex_lock(struct rt_mutex *lock);
  89 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
  90                                                 int detect_deadlock);
  91 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
  92                                         struct hrtimer_sleeper *timeout,
  93                                         int detect_deadlock);
  94
  95 extern int rt_mutex_trylock(struct rt_mutex *lock);
  96
  97 extern void rt_mutex_unlock(struct rt_mutex *lock);
  98
  99 #ifdef CONFIG_RT_MUTEXES
 100 # define INIT_RT_MUTEXES(tsk)                                           \
 101         .pi_waiters     = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
 102         INIT_RT_MUTEX_DEBUG(tsk)
 103 #else
 104 # define INIT_RT_MUTEXES(tsk)
 105 #endif
 106
 107 #endif