LXR linux/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
  19extern 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 */
  29struct 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
  42struct rt_mutex_waiter;
  43struct 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 */
  84static inline int rt_mutex_is_locked(struct rt_mutex *lock)
  85{
  86        return lock->owner != NULL;
  87}
  88
  89extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
  90extern void rt_mutex_destroy(struct rt_mutex *lock);
  91
  92extern void rt_mutex_lock(struct rt_mutex *lock);
  93extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
  94extern int rt_mutex_timed_lock(struct rt_mutex *lock,
  95                               struct hrtimer_sleeper *timeout);
  96
  97extern int rt_mutex_trylock(struct rt_mutex *lock);
  98
  99extern void rt_mutex_unlock(struct rt_mutex *lock);
 100
 101#endif
 102