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 <[email protected]> 8 * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <[email protected]> 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_LOCK_ALLOC 35 struct lockdep_map dep_map; 36 #endif 37 }; 38 39 struct rt_mutex_waiter; 40 struct hrtimer_sleeper; 41 42 #ifdef CONFIG_DEBUG_RT_MUTEXES 43 extern int rt_mutex_debug_check_no_locks_freed(const void *from, 44 unsigned long len); 45 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task); 46 #else 47 static inline int rt_mutex_debug_check_no_locks_freed(const void *from, 48 unsigned long len) 49 { 50 return 0; 51 } 52 # define rt_mutex_debug_check_no_locks_held(task) do { } while (0) 53 #endif 54 55 #ifdef CONFIG_DEBUG_RT_MUTEXES 56 57 # define rt_mutex_init(mutex) \ 58 do { \ 59 static struct lock_class_key __key; \ 60 __rt_mutex_init(mutex, __func__, &__key); \ 61 } while (0) 62 63 extern void rt_mutex_debug_task_free(struct task_struct *tsk); 64 #else 65 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL, NULL) 66 # define rt_mutex_debug_task_free(t) do { } while (0) 67 #endif 68 69 #ifdef CONFIG_DEBUG_LOCK_ALLOC 70 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \ 71 , .dep_map = { .name = #mutexname } 72 #else 73 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) 74 #endif 75 76 #define __RT_MUTEX_INITIALIZER(mutexname) \ 77 { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \ 78 , .waiters = RB_ROOT_CACHED \ 79 , .owner = NULL \ 80 __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)} 81 82 #define DEFINE_RT_MUTEX(mutexname) \ 83 struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname) 84 85 /** 86 * rt_mutex_is_locked - is the mutex locked 87 * @lock: the mutex to be queried 88 * 89 * Returns 1 if the mutex is locked, 0 if unlocked. 90 */ 91 static inline int rt_mutex_is_locked(struct rt_mutex *lock) 92 { 93 return lock->owner != NULL; 94 } 95 96 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key); 97 extern void rt_mutex_destroy(struct rt_mutex *lock); 98 99 #ifdef CONFIG_DEBUG_LOCK_ALLOC 100 extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass); 101 #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0) 102 #else 103 extern void rt_mutex_lock(struct rt_mutex *lock); 104 #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock) 105 #endif 106 107 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); 108 extern int rt_mutex_trylock(struct rt_mutex *lock); 109 110 extern void rt_mutex_unlock(struct rt_mutex *lock); 111 112 #endif 113