rtmutex.h

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/*
 * RT Mutexes: blocking mutual exclusion locks with PI support
 *
 * started by Ingo Molnar and Thomas Gleixner:
 *
 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <[email protected]>
 *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <[email protected]>
 *
 * This file contains the public data structure and API definitions.
 */

#ifndef __LINUX_RT_MUTEX_H
#define __LINUX_RT_MUTEX_H

#include <linux/linkage.h>
#include <linux/plist.h>
#include <linux/spinlock_types.h>

extern int max_lock_depth; /* for sysctl */

struct rt_mutex {
    raw_spinlock_t      wait_lock;
    struct plist_head   wait_list;
    struct task_struct  *owner;
#ifdef CONFIG_DEBUG_RT_MUTEXES
    int         save_state;
    const char      *name, *file;
    int         line;
    void            *magic;
#endif
};

struct rt_mutex_waiter;
struct hrtimer_sleeper;

#ifdef CONFIG_DEBUG_RT_MUTEXES
 extern int rt_mutex_debug_check_no_locks_freed(const void *from,
                        unsigned long len);
 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
#else
 static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
                               unsigned long len)
 {
    return 0;
 }
# define rt_mutex_debug_check_no_locks_held(task)   do { } while (0)
#endif

#ifdef CONFIG_DEBUG_RT_MUTEXES
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
    , .name = #mutexname, .file = __FILE__, .line = __LINE__
# define rt_mutex_init(mutex)           __rt_mutex_init(mutex, __func__)
 extern void rt_mutex_debug_task_free(struct task_struct *tsk);
#else
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
# define rt_mutex_init(mutex)           __rt_mutex_init(mutex, NULL)
# define rt_mutex_debug_task_free(t)            do { } while (0)
#endif

#define __RT_MUTEX_INITIALIZER(mutexname) \
    { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
    , .wait_list = PLIST_HEAD_INIT(mutexname.wait_list) \
    , .owner = NULL \
    __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}

#define DEFINE_RT_MUTEX(mutexname) \
    struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)

static inline int rt_mutex_is_locked(struct rt_mutex *lock)
{
    return lock->owner != NULL;
}

extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
extern void rt_mutex_destroy(struct rt_mutex *lock);

extern void rt_mutex_lock(struct rt_mutex *lock);
extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
                        int detect_deadlock);
extern int rt_mutex_timed_lock(struct rt_mutex *lock,
                    struct hrtimer_sleeper *timeout,
                    int detect_deadlock);

extern int rt_mutex_trylock(struct rt_mutex *lock);

extern void rt_mutex_unlock(struct rt_mutex *lock);

#ifdef CONFIG_RT_MUTEXES
# define INIT_RT_MUTEXES(tsk)                       \
    .pi_waiters = PLIST_HEAD_INIT(tsk.pi_waiters),  \
    INIT_RT_MUTEX_DEBUG(tsk)
#else
# define INIT_RT_MUTEXES(tsk)
#endif

#endif