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 <mingo@redhat.com> 7 * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com> 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 }; 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, .file = __FILE__, .line = __LINE__ 61 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, __func__) 62 extern void rt_mutex_debug_task_free(struct task_struct *tsk); 63 #else 64 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) 65 # define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL) 66 # define rt_mutex_debug_task_free(t) do { } while (0) 67 #endif 68 69 #define __RT_MUTEX_INITIALIZER(mutexname) \ 70 { .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \ 71 , .waiters = RB_ROOT \ 72 , .owner = NULL \ 73 __DEBUG_RT_MUTEX_INITIALIZER(mutexname)} 74 75 #define DEFINE_RT_MUTEX(mutexname) \ 76 struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname) 77 78 /** 79 * rt_mutex_is_locked - is the mutex locked 80 * @lock: the mutex to be queried 81 * 82 * Returns 1 if the mutex is locked, 0 if unlocked. 83 */ 84 static inline int rt_mutex_is_locked(struct rt_mutex *lock) 85 { 86 return lock->owner != NULL; 87 } 88 89 extern void __rt_mutex_init(struct rt_mutex *lock, const char *name); 90 extern void rt_mutex_destroy(struct rt_mutex *lock); 91 92 extern void rt_mutex_lock(struct rt_mutex *lock); 93 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); 94 extern int rt_mutex_timed_lock(struct rt_mutex *lock, 95 struct hrtimer_sleeper *timeout); 96 97 extern int rt_mutex_trylock(struct rt_mutex *lock); 98 99 extern void rt_mutex_unlock(struct rt_mutex *lock); 100 101 #endif 102