linux/include/linux/rtmutex.h
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   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
  19extern 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 */
  28struct 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
  40struct rt_mutex_waiter;
  41struct 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(mutexname.wait_list) \
  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 */
  82static inline int rt_mutex_is_locked(struct rt_mutex *lock)
  83{
  84        return lock->owner != NULL;
  85}
  86
  87extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
  88extern void rt_mutex_destroy(struct rt_mutex *lock);
  89
  90extern void rt_mutex_lock(struct rt_mutex *lock);
  91extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
  92                                                int detect_deadlock);
  93extern int rt_mutex_timed_lock(struct rt_mutex *lock,
  94                                        struct hrtimer_sleeper *timeout,
  95                                        int detect_deadlock);
  96
  97extern int rt_mutex_trylock(struct rt_mutex *lock);
  98
  99extern 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),      \
 104        INIT_RT_MUTEX_DEBUG(tsk)
 105#else
 106# define INIT_RT_MUTEXES(tsk)
 107#endif
 108
 109#endif
 110
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