Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : /*
       3             :  * RT Mutexes: blocking mutual exclusion locks with PI support
       4             :  *
       5             :  * started by Ingo Molnar and Thomas Gleixner:
       6             :  *
       7             :  *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
       8             :  *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
       9             :  *
      10             :  * This file contains the public data structure and API definitions.
      11             :  */
      12             : 
      13             : #ifndef __LINUX_RT_MUTEX_H
      14             : #define __LINUX_RT_MUTEX_H
      15             : 
      16             : #include <linux/linkage.h>
      17             : #include <linux/rbtree.h>
      18             : #include <linux/spinlock_types.h>
      19             : 
      20             : extern int max_lock_depth; /* for sysctl */
      21             : 
      22             : /**
      23             :  * The rt_mutex structure
      24             :  *
      25             :  * @wait_lock:  spinlock to protect the structure
      26             :  * @waiters:    rbtree root to enqueue waiters in priority order;
      27             :  *              caches top-waiter (leftmost node).
      28             :  * @owner:      the mutex owner
      29             :  */
      30             : struct rt_mutex {
      31             :         raw_spinlock_t          wait_lock;
      32             :         struct rb_root_cached   waiters;
      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             : #ifdef CONFIG_DEBUG_LOCK_ALLOC
      41             :         struct lockdep_map      dep_map;
      42             : #endif
      43             : };
      44             : 
      45             : struct rt_mutex_waiter;
      46             : struct hrtimer_sleeper;
      47             : 
      48             : #ifdef CONFIG_DEBUG_RT_MUTEXES
      49             :  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
      50             :                                                 unsigned long len);
      51             :  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
      52             : #else
      53             :  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
      54             :                                                        unsigned long len)
      55             :  {
      56             :         return 0;
      57             :  }
      58             : # define rt_mutex_debug_check_no_locks_held(task)       do { } while (0)
      59             : #endif
      60             : 
      61             : #ifdef CONFIG_DEBUG_RT_MUTEXES
      62             : # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
      63             :         , .name = #mutexname, .file = __FILE__, .line = __LINE__
      64             : 
      65             : # define rt_mutex_init(mutex) \
      66             : do { \
      67             :         static struct lock_class_key __key; \
      68             :         __rt_mutex_init(mutex, __func__, &__key); \
      69             : } while (0)
      70             : 
      71             :  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
      72             : #else
      73             : # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
      74             : # define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, NULL, NULL)
      75             : # define rt_mutex_debug_task_free(t)                    do { } while (0)
      76             : #endif
      77             : 
      78             : #ifdef CONFIG_DEBUG_LOCK_ALLOC
      79             : #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
      80             :         , .dep_map = { .name = #mutexname }
      81             : #else
      82             : #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
      83             : #endif
      84             : 
      85             : #define __RT_MUTEX_INITIALIZER(mutexname) \
      86             :         { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
      87             :         , .waiters = RB_ROOT_CACHED \
      88             :         , .owner = NULL \
      89             :         __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
      90             :         __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
      91             : 
      92             : #define DEFINE_RT_MUTEX(mutexname) \
      93             :         struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
      94             : 
      95             : /**
      96             :  * rt_mutex_is_locked - is the mutex locked
      97             :  * @lock: the mutex to be queried
      98             :  *
      99             :  * Returns 1 if the mutex is locked, 0 if unlocked.
     100             :  */
     101           0 : static inline int rt_mutex_is_locked(struct rt_mutex *lock)
     102             : {
     103           0 :         return lock->owner != NULL;
     104             : }
     105             : 
     106             : extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
     107             : extern void rt_mutex_destroy(struct rt_mutex *lock);
     108             : 
     109             : #ifdef CONFIG_DEBUG_LOCK_ALLOC
     110             : extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
     111             : #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
     112             : #else
     113             : extern void rt_mutex_lock(struct rt_mutex *lock);
     114             : #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
     115             : #endif
     116             : 
     117             : extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
     118             : extern int rt_mutex_timed_lock(struct rt_mutex *lock,
     119             :                                struct hrtimer_sleeper *timeout);
     120             : 
     121             : extern int rt_mutex_trylock(struct rt_mutex *lock);
     122             : 
     123             : extern void rt_mutex_unlock(struct rt_mutex *lock);
     124             : 
     125             : #endif