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/*

 * kernel/mutex-debug.c

 *

 * 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/module.h>

#include <linux/poison.h>

#include <linux/spinlock.h>

#include <linux/kallsyms.h>

#include <linux/interrupt.h>

#include <linux/debug_locks.h>

#include "mutex-debug.h"

/*

 * Must be called with lock->wait_lock held.

 */

void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)

{

        lock->owner = new_owner;

}

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);

}

void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)

{

        SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&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 thread_info *ti)

{

        SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));

        /* Mark the current thread as blocked on the lock: */

        ti->task->blocked_on = waiter;

        waiter->lock = lock;

}

void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,

                         struct thread_info *ti)

{

        DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));

        DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);

        DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);

        ti->task->blocked_on = NULL;

        list_del_init(&waiter->list);

        waiter->task = NULL;

}

void debug_mutex_unlock(struct mutex *lock)

{

        if (unlikely(!debug_locks))

                return;

        DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());

        DEBUG_LOCKS_WARN_ON(lock->magic != lock);

        DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);

        DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());

}

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(&lock->dep_map, name, key, 0);

#endif

        lock->owner = NULL;

        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 fastcall mutex_destroy(struct mutex *lock)

{

        DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));

        lock->magic = NULL;

}

EXPORT_SYMBOL_GPL(mutex_destroy);