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