LXR linux/include/linux/rtmutex.h

   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/compiler.h>
  17#include <linux/linkage.h>
  18#include <linux/rbtree_types.h>
  19#include <linux/spinlock_types_raw.h>
  20
  21extern int max_lock_depth; /* for sysctl */
  22
  23struct rt_mutex_base {
  24        raw_spinlock_t          wait_lock;
  25        struct rb_root_cached   waiters;
  26        struct task_struct      *owner;
  27};
  28
  29#define __RT_MUTEX_BASE_INITIALIZER(rtbasename)                         \
  30{                                                                       \
  31        .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(rtbasename.wait_lock),    \
  32        .waiters = RB_ROOT_CACHED,                                      \
  33        .owner = NULL                                                   \
  34}
  35
  36/**
  37 * rt_mutex_base_is_locked - is the rtmutex locked
  38 * @lock: the mutex to be queried
  39 *
  40 * Returns true if the mutex is locked, false if unlocked.
  41 */
  42static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock)
  43{
  44        return READ_ONCE(lock->owner) != NULL;
  45}
  46
  47extern void rt_mutex_base_init(struct rt_mutex_base *rtb);
  48
  49/**
  50 * The rt_mutex structure
  51 *
  52 * @wait_lock:  spinlock to protect the structure
  53 * @waiters:    rbtree root to enqueue waiters in priority order;
  54 *              caches top-waiter (leftmost node).
  55 * @owner:      the mutex owner
  56 */
  57struct rt_mutex {
  58        struct rt_mutex_base    rtmutex;
  59#ifdef CONFIG_DEBUG_LOCK_ALLOC
  60        struct lockdep_map      dep_map;
  61#endif
  62};
  63
  64struct rt_mutex_waiter;
  65struct hrtimer_sleeper;
  66
  67#ifdef CONFIG_DEBUG_RT_MUTEXES
  68extern void rt_mutex_debug_task_free(struct task_struct *tsk);
  69#else
  70static inline void rt_mutex_debug_task_free(struct task_struct *tsk) { }
  71#endif
  72
  73#define rt_mutex_init(mutex) \
  74do { \
  75        static struct lock_class_key __key; \
  76        __rt_mutex_init(mutex, __func__, &__key); \
  77} while (0)
  78
  79#ifdef CONFIG_DEBUG_LOCK_ALLOC
  80#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)       \
  81        .dep_map = {                                    \
  82                .name = #mutexname,                     \
  83                .wait_type_inner = LD_WAIT_SLEEP,       \
  84        }
  85#else
  86#define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
  87#endif
  88
  89#define __RT_MUTEX_INITIALIZER(mutexname)                               \
  90{                                                                       \
  91        .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex),      \
  92        __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)                       \
  93}
  94
  95#define DEFINE_RT_MUTEX(mutexname) \
  96        struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
  97
  98extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key);
  99
 100#ifdef CONFIG_DEBUG_LOCK_ALLOC
 101extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
 102extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock);
 103#define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
 104#define rt_mutex_lock_nest_lock(lock, nest_lock)                        \
 105        do {                                                            \
 106                typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
 107                _rt_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map);  \
 108        } while (0)
 109
 110#else
 111extern void rt_mutex_lock(struct rt_mutex *lock);
 112#define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
 113#define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock)
 114#endif
 115
 116extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
 117extern int rt_mutex_lock_killable(struct rt_mutex *lock);
 118extern int rt_mutex_trylock(struct rt_mutex *lock);
 119
 120extern void rt_mutex_unlock(struct rt_mutex *lock);
 121
 122#endif
 123