/* * Debugging code for mutexes * * Started by Ingo Molnar: * *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> * * lock debugging, locking tree, deadlock detection started by: * *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey *  Released under the General Public License (GPL). */#include <linux/mutex.h>#include <linux/delay.h>#include <linux/export.h>#include <linux/poison.h>#include <linux/sched.h>#include <linux/spinlock.h>#include <linux/kallsyms.h>#include <linux/interrupt.h>#include <linux/debug_locks.h> #include "mutex.h" /* * Must be called with lock->wait_lock held. */void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter){	memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));	waiter->magic = waiter;	INIT_LIST_HEAD(&waiter->list);	waiter->ww_ctx = MUTEX_POISON_WW_CTX;} void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter){	lockdep_assert_held(&lock->wait_lock);	DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));	DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));} void debug_mutex_free_waiter(struct mutex_waiter *waiter){	DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));	memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));} void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,			    struct task_struct *task){	lockdep_assert_held(&lock->wait_lock); 	/* Mark the current thread as blocked on the lock: */	task->blocked_on = waiter;} void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,			 struct task_struct *task){	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));	DEBUG_LOCKS_WARN_ON(waiter->task != task);	DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);	task->blocked_on = NULL; 	INIT_LIST_HEAD(&waiter->list);	waiter->task = NULL;} void debug_mutex_unlock(struct mutex *lock){	if (likely(debug_locks)) {		DEBUG_LOCKS_WARN_ON(lock->magic != lock);		DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);	}} void debug_mutex_init(struct mutex *lock, const char *name,		      struct lock_class_key *key){#ifdef CONFIG_DEBUG_LOCK_ALLOC	/*	 * Make sure we are not reinitializing a held lock:	 */	debug_check_no_locks_freed((void *)lock, sizeof(*lock));	lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);#endif	lock->magic = lock;} /*** * mutex_destroy - mark a mutex unusable * @lock: the mutex to be destroyed * * This function marks the mutex uninitialized, and any subsequent * use of the mutex is forbidden. The mutex must not be locked when * this function is called. */void mutex_destroy(struct mutex *lock){	DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));	lock->magic = NULL;} EXPORT_SYMBOL_GPL(mutex_destroy);