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 extern int max_lock_depth; /* for sysctl */
  20
  21 /**
  22  * The rt_mutex structure
  23  *
  24  * @wait_lock:  spinlock to protect the structure
  25  * @wait_list:  pilist head to enqueue waiters in priority order
  26  * @owner:      the mutex owner
  27  */
  28 struct rt_mutex {
  29         raw_spinlock_t          wait_lock;
  30         struct plist_head       wait_list;
  31         struct task_struct      *owner;
  32 #ifdef CONFIG_DEBUG_RT_MUTEXES
  33         int                     save_state;
  34         const char              *name, *file;
  35         int                     line;
  36         void                    *magic;
  37 #endif
  38 };
  39
  40 struct rt_mutex_waiter;
  41 struct hrtimer_sleeper;
  42
  43 #ifdef CONFIG_DEBUG_RT_MUTEXES
  44  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
  45                                                 unsigned long len);
  46  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
  47 #else
  48  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
  49                                                        unsigned long len)
  50  {
  51         return 0;
  52  }
  53 # define rt_mutex_debug_check_no_locks_held(task)       do { } while (0)
  54 #endif
  55
  56 #ifdef CONFIG_DEBUG_RT_MUTEXES
  57 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
  58         , .name = #mutexname, .file = __FILE__, .line = __LINE__
  59 # define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, __func__)
  60  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
  61 #else
  62 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
  63 # define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, NULL)
  64 # define rt_mutex_debug_task_free(t)                    do { } while (0)
  65 #endif
  66
  67 #define __RT_MUTEX_INITIALIZER(mutexname) \
  68         { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
  69         , .wait_list = PLIST_HEAD_INIT_RAW(mutexname.wait_list, mutexname.wait_lock) \
  70         , .owner = NULL \
  71         __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
  72
  73 #define DEFINE_RT_MUTEX(mutexname) \
  74         struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
  75
  76 /**
  77  * rt_mutex_is_locked - is the mutex locked
  78  * @lock: the mutex to be queried
  79  *
  80  * Returns 1 if the mutex is locked, 0 if unlocked.
  81  */
  82 static inline int rt_mutex_is_locked(struct rt_mutex *lock)
  83 {
  84         return lock->owner != NULL;
  85 }
  86
  87 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
  88 extern void rt_mutex_destroy(struct rt_mutex *lock);
  89
  90 extern void rt_mutex_lock(struct rt_mutex *lock);
  91 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
  92                                                 int detect_deadlock);
  93 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
  94                                         struct hrtimer_sleeper *timeout,
  95                                         int detect_deadlock);
  96
  97 extern int rt_mutex_trylock(struct rt_mutex *lock);
  98
  99 extern void rt_mutex_unlock(struct rt_mutex *lock);
 100
 101 #ifdef CONFIG_RT_MUTEXES
 102 # define INIT_RT_MUTEXES(tsk)                                           \
 103         .pi_waiters     = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
 104         INIT_RT_MUTEX_DEBUG(tsk)
 105 #else
 106 # define INIT_RT_MUTEXES(tsk)
 107 #endif
 108
 109 #endif