lockdep: Print lock name in lockdep_init_error()

This patch prints the name of the lock which is acquired
before lockdep_init() is called, so that users can easily
find which lock triggered the lockdep init error warning.

This patch also removes the lockdep_init_error() message
of "Arch code didn't call lockdep_init() early enough?"
since lockdep_init() is called in arch independent code now.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1321508072-23853-2-git-send-email-tom.leiming@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/lockdep.c

@@ -431,6 +431,7 @@ unsigned int max_lockdep_depth;
  * about it later on, in lockdep_info().
  */
 static int lockdep_init_error;
+static const char *lock_init_error;
 static unsigned long lockdep_init_trace_data[20];
 static struct stack_trace lockdep_init_trace = {
 	.max_entries = ARRAY_SIZE(lockdep_init_trace_data),
@@ -657,6 +658,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
 	if (unlikely(!lockdep_initialized)) {
 		lockdep_init();
 		lockdep_init_error = 1;
+		lock_init_error = lock->name;
 		save_stack_trace(&lockdep_init_trace);
 	}
 #endif
@@ -3978,7 +3980,8 @@ void __init lockdep_info(void)
 
 #ifdef CONFIG_DEBUG_LOCKDEP
 	if (lockdep_init_error) {
-		printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+		printk("WARNING: lockdep init error! lock-%s was acquired"
+			"before lockdep_init\n", lock_init_error);
 		printk("Call stack leading to lockdep invocation was:\n");
 		print_stack_trace(&lockdep_init_trace, 0);
 	}