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 * @waiters_leftmost: top waiter 27 * @owner: the mutex owner 28 */ 29 struct rt_mutex { 30 raw_spinlock_t wait_lock; 31 struct rb_root waiters; 32 struct rb_node *waiters_leftmost; 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 \ 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 static inline int rt_mutex_is_locked(struct rt_mutex *lock) 102 { 103 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 extern void rt_mutex_lock(struct rt_mutex *lock); 110 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); 111 extern int rt_mutex_timed_lock(struct rt_mutex *lock, 112 struct hrtimer_sleeper *timeout); 113 114 extern int rt_mutex_trylock(struct rt_mutex *lock); 115 116 extern void rt_mutex_unlock(struct rt_mutex *lock); 117 118 #endif 119