1 files changed, 110 insertions, 0 deletions

diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
new file mode 100644
index 000000000000..7e3443fe1f48
--- /dev/null
+++ b/kernel/locking/mutex-debug.c
@@ -0,0 +1,110 @@
+/*
+ * 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/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-debug.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);
+}
+
+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;
+}
+
+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->magic != lock);
+        DEBUG_LOCKS_WARN_ON(lock->owner != current);
+        DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+        mutex_clear_owner(lock);
+}
+
+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->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);