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