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 <[email protected]> 7 * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <[email protected]> 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/rbtree.h> 17 #include <linux/spinlock_types.h> 18 19 extern int max_lock_depth; /* for sysctl */ 20 21 /** 22 * The rt_mutex structure 23 * 24 * @wait_lock: spinlock to protect the structure 25 * @waiters: rbtree root to enqueue waiters in priority order; 26 * caches top-waiter (leftmost node). 27 * @owner: the mutex owner 28 */ 29 struct rt_mutex { 30 raw_spinlock_t wait_lock; 31 struct rb_root_cached waiters; 32 struct task_struct *owner; 33 #ifdef CONFIG_DEBUG_RT_MUTEXES 34 int save_state; 35 const char *name, *file; 36 int line; 37 void *magic; 38 #endif 39 #ifdef CONFIG_DEBUG_LOCK_ALLOC 40 struct lockdep_map dep_map; 41 #endif 42 }; 43 44 struct rt_mutex_waiter; 45 struct hrtimer_sleeper; 46 47 #ifdef CONFIG_DEBUG_RT_MUTEXES 48 extern int rt_mutex_debug_check_no_locks_freed(const void *from, 49 unsigned long len); 50 extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task); 51 #else 52 static inline int rt_mutex_debug_check_no_locks_freed(const void *from, 53 unsigned long len) 54 { 55 return 0; 56 } 57 # define rt_mutex_debug_check_no_locks_held(task) do { } while (0) 58 #endif 59 60 #ifdef CONFIG_DEBUG_RT_MUTEXES 61 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ 62 , .name = #mutexname, .file = __FILE__, .line = __LINE__ 63 64 # define rt_mutex_init(mutex) \ 65 do { \ 66 static struct lock_class_key __key; \ 67 __rt_mutex_init(mutex, __func__, &__key); \ 68 } while (0) 69 70 extern void rt_mutex_debug_task_free(struct task_struct *tsk); 71 #else 72 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) 73 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL, NULL) 74 # define rt_mutex_debug_task_free(t) do { } while (0) 75 #endif 76 77 #ifdef CONFIG_DEBUG_LOCK_ALLOC 78 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \ 79 , .dep_map = { .name = #mutexname } 80 #else 81 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) 82 #endif 83 84 #define __RT_MUTEX_INITIALIZER(mutexname) \ 85 { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \ 86 , .waiters = RB_ROOT_CACHED \ 87 , .owner = NULL \ 88 __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ 89 __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)} 90 91 #define DEFINE_RT_MUTEX(mutexname) \ 92 struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname) 93 94 /** 95 * rt_mutex_is_locked - is the mutex locked 96 * @lock: the mutex to be queried 97 * 98 * Returns 1 if the mutex is locked, 0 if unlocked. 99 */ 100 static inline int rt_mutex_is_locked(struct rt_mutex *lock) 101 { 102 return lock->owner != NULL; 103 } 104 105 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key); 106 extern void rt_mutex_destroy(struct rt_mutex *lock); 107 108 extern void rt_mutex_lock(struct rt_mutex *lock); 109 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); 110 extern int rt_mutex_timed_lock(struct rt_mutex *lock, 111 struct hrtimer_sleeper *timeout); 112 113 extern int rt_mutex_trylock(struct rt_mutex *lock); 114 115 extern void rt_mutex_unlock(struct rt_mutex *lock); 116 117 #endif 118