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_RT_MUTEXES 35 const char *name; 36 #endif 37 #ifdef CONFIG_DEBUG_LOCK_ALLOC 38 struct lockdep_map dep_map; 39 #endif 40 }; 41 42 struct rt_mutex_waiter; 43 struct hrtimer_sleeper; 44 45 #ifdef CONFIG_DEBUG_RT_MUTEXES 46 extern int rt_mutex_debug_check_no_locks_freed(const void *from, 47 unsigned long len); 48 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task); 49 #else 50 static inline int rt_mutex_debug_check_no_locks_freed(const void *from, 51 unsigned long len) 52 { 53 return 0; 54 } 55 # define rt_mutex_debug_check_no_locks_held(task) do { } while (0) 56 #endif 57 58 #ifdef CONFIG_DEBUG_RT_MUTEXES 59 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ 60 , .name = #mutexname 61 62 # define rt_mutex_init(mutex) \ 63 do { \ 64 static struct lock_class_key __key; \ 65 __rt_mutex_init(mutex, __func__, &__key); \ 66 } while (0) 67 68 extern void rt_mutex_debug_task_free(struct task_struct *tsk); 69 #else 70 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) 71 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL, NULL) 72 # define rt_mutex_debug_task_free(t) do { } while (0) 73 #endif 74 75 #ifdef CONFIG_DEBUG_LOCK_ALLOC 76 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \ 77 , .dep_map = { .name = #mutexname } 78 #else 79 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) 80 #endif 81 82 #define __RT_MUTEX_INITIALIZER(mutexname) \ 83 { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \ 84 , .waiters = RB_ROOT_CACHED \ 85 , .owner = NULL \ 86 __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ 87 __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)} 88 89 #define DEFINE_RT_MUTEX(mutexname) \ 90 struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname) 91 92 /** 93 * rt_mutex_is_locked - is the mutex locked 94 * @lock: the mutex to be queried 95 * 96 * Returns 1 if the mutex is locked, 0 if unlocked. 97 */ 98 static inline int rt_mutex_is_locked(struct rt_mutex *lock) 99 { 100 return lock->owner != NULL; 101 } 102 103 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key); 104 extern void rt_mutex_destroy(struct rt_mutex *lock); 105 106 #ifdef CONFIG_DEBUG_LOCK_ALLOC 107 extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass); 108 #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0) 109 #else 110 extern void rt_mutex_lock(struct rt_mutex *lock); 111 #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock) 112 #endif 113 114 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); 115 extern int rt_mutex_trylock(struct rt_mutex *lock); 116 117 extern void rt_mutex_unlock(struct rt_mutex *lock); 118 119 #endif 120