[PATCH] mutex subsystem, debugging code

mutex implementation - add debugging code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
new file mode 100644
index 00000000000..fd384050acb
--- /dev/null
+++ b/kernel/mutex-debug.h
@@ -0,0 +1,134 @@
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal declarations,
+ * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
+ * More details are in kernel/mutex-debug.c.
+ */
+
+extern spinlock_t debug_mutex_lock;
+extern struct list_head debug_mutex_held_locks;
+extern int debug_mutex_on;
+
+/*
+ * In the debug case we carry the caller's instruction pointer into
+ * other functions, but we dont want the function argument overhead
+ * in the nondebug case - hence these macros:
+ */
+#define __IP_DECL__		, unsigned long ip
+#define __IP__			, ip
+#define __RET_IP__		, (unsigned long)__builtin_return_address(0)
+
+/*
+ * This must be called with lock->wait_lock held.
+ */
+extern void debug_mutex_set_owner(struct mutex *lock,
+				  struct thread_info *new_owner __IP_DECL__);
+
+static inline void debug_mutex_clear_owner(struct mutex *lock)
+{
+	lock->owner = NULL;
+}
+
+extern void debug_mutex_init_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+				    struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+				   struct mutex_waiter *waiter,
+				   struct thread_info *ti __IP_DECL__);
+extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+				struct thread_info *ti);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name);
+
+#define debug_spin_lock(lock)				\
+	do {						\
+		local_irq_disable();			\
+		if (debug_mutex_on)			\
+			spin_lock(lock);		\
+	} while (0)
+
+#define debug_spin_unlock(lock)				\
+	do {						\
+		if (debug_mutex_on)			\
+			spin_unlock(lock);		\
+		local_irq_enable();			\
+		preempt_check_resched();		\
+	} while (0)
+
+#define debug_spin_lock_save(lock, flags)		\
+	do {						\
+		local_irq_save(flags);			\
+		if (debug_mutex_on)			\
+			spin_lock(lock);		\
+	} while (0)
+
+#define debug_spin_lock_restore(lock, flags)		\
+	do {						\
+		if (debug_mutex_on)			\
+			spin_unlock(lock);		\
+		local_irq_restore(flags);		\
+		preempt_check_resched();		\
+	} while (0)
+
+#define spin_lock_mutex(lock)				\
+	do {						\
+		struct mutex *l = container_of(lock, struct mutex, wait_lock); \
+							\
+		DEBUG_WARN_ON(in_interrupt());		\
+		debug_spin_lock(&debug_mutex_lock);	\
+		spin_lock(lock);			\
+		DEBUG_WARN_ON(l->magic != l);		\
+	} while (0)
+
+#define spin_unlock_mutex(lock)				\
+	do {						\
+		spin_unlock(lock);			\
+		debug_spin_unlock(&debug_mutex_lock);	\
+	} while (0)
+
+#define DEBUG_OFF()					\
+do {							\
+	if (debug_mutex_on) {				\
+		debug_mutex_on = 0;			\
+		console_verbose();			\
+		if (spin_is_locked(&debug_mutex_lock))	\
+			spin_unlock(&debug_mutex_lock);	\
+	}						\
+} while (0)
+
+#define DEBUG_BUG()					\
+do {							\
+	if (debug_mutex_on) {				\
+		DEBUG_OFF();				\
+		BUG();					\
+	}						\
+} while (0)
+
+#define DEBUG_WARN_ON(c)				\
+do {							\
+	if (unlikely(c && debug_mutex_on)) {		\
+		DEBUG_OFF();				\
+		WARN_ON(1);				\
+	}						\
+} while (0)
+
+# define DEBUG_BUG_ON(c)				\
+do {							\
+	if (unlikely(c))				\
+		DEBUG_BUG();				\
+} while (0)
+
+#ifdef CONFIG_SMP
+# define SMP_DEBUG_WARN_ON(c)			DEBUG_WARN_ON(c)
+# define SMP_DEBUG_BUG_ON(c)			DEBUG_BUG_ON(c)
+#else
+# define SMP_DEBUG_WARN_ON(c)			do { } while (0)
+# define SMP_DEBUG_BUG_ON(c)			do { } while (0)
+#endif
+