X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=kernel%2Flockdep.c;h=7065a687ac546020de4d53883f188f9702e036fd;hb=83aa0938ff59e8ef6d0b99260063ebe84fc84a16;hp=509efd49540f9beb09ddf347725690f939e09aa2;hpb=975a8e3ed2b9eab9f062a1e0ba7fe180e15204e1;p=powerpc.git

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 509efd4954..7065a687ac 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -70,6 +70,9 @@ static int graph_lock(void)
 
 static inline int graph_unlock(void)
 {
+	if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
+		return DEBUG_LOCKS_WARN_ON(1);
+
 	__raw_spin_unlock(&lockdep_lock);
 	return 0;
 }
@@ -487,7 +490,7 @@ static void print_lock_dependencies(struct lock_class *class, int depth)
  * Add a new dependency to the head of the list:
  */
 static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
-			    struct list_head *head, unsigned long ip)
+			    struct list_head *head, unsigned long ip, int distance)
 {
 	struct lock_list *entry;
 	/*
@@ -499,6 +502,7 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
 		return 0;
 
 	entry->class = this;
+	entry->distance = distance;
 	if (!save_trace(&entry->trace))
 		return 0;
 
@@ -712,6 +716,9 @@ find_usage_backwards(struct lock_class *source, unsigned int depth)
 	struct lock_list *entry;
 	int ret;
 
+	if (!__raw_spin_is_locked(&lockdep_lock))
+		return DEBUG_LOCKS_WARN_ON(1);
+
 	if (depth > max_recursion_depth)
 		max_recursion_depth = depth;
 	if (depth >= RECURSION_LIMIT)
@@ -900,7 +907,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
  */
 static int
 check_prev_add(struct task_struct *curr, struct held_lock *prev,
-	       struct held_lock *next)
+	       struct held_lock *next, int distance)
 {
 	struct lock_list *entry;
 	int ret;
@@ -978,8 +985,11 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
 	 *  L2 added to its dependency list, due to the first chain.)
 	 */
 	list_for_each_entry(entry, &prev->class->locks_after, entry) {
-		if (entry->class == next->class)
+		if (entry->class == next->class) {
+			if (distance == 1)
+				entry->distance = 1;
 			return 2;
+		}
 	}
 
 	/*
@@ -987,12 +997,13 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
 	 * to the previous lock's dependency list:
 	 */
 	ret = add_lock_to_list(prev->class, next->class,
-			       &prev->class->locks_after, next->acquire_ip);
+			       &prev->class->locks_after, next->acquire_ip, distance);
+
 	if (!ret)
 		return 0;
 
 	ret = add_lock_to_list(next->class, prev->class,
-			       &next->class->locks_before, next->acquire_ip);
+			       &next->class->locks_before, next->acquire_ip, distance);
 	if (!ret)
 		return 0;
 
@@ -1040,13 +1051,14 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
 		goto out_bug;
 
 	for (;;) {
+		int distance = curr->lockdep_depth - depth + 1;
 		hlock = curr->held_locks + depth-1;
 		/*
 		 * Only non-recursive-read entries get new dependencies
 		 * added:
 		 */
 		if (hlock->read != 2) {
-			if (!check_prev_add(curr, hlock, next))
+			if (!check_prev_add(curr, hlock, next, distance))
 				return 0;
 			/*
 			 * Stop after the first non-trylock entry,
@@ -1293,7 +1305,8 @@ out_unlock_set:
 	if (!subclass || force)
 		lock->class_cache = class;
 
-	DEBUG_LOCKS_WARN_ON(class->subclass != subclass);
+	if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+		return NULL;
 
 	return class;
 }
@@ -1308,7 +1321,8 @@ static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
 	struct list_head *hash_head = chainhashentry(chain_key);
 	struct lock_chain *chain;
 
-	DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return 0;
 	/*
 	 * We can walk it lock-free, because entries only get added
 	 * to the hash:
@@ -1394,7 +1408,9 @@ static void check_chain_key(struct task_struct *curr)
 			return;
 		}
 		id = hlock->class - lock_classes;
-		DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS);
+		if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+			return;
+
 		if (prev_hlock && (prev_hlock->irq_context !=
 							hlock->irq_context))
 			chain_key = 0;
@@ -2205,15 +2221,24 @@ out_calc_hash:
 			if (!check_prevs_add(curr, hlock))
 				return 0;
 		graph_unlock();
-	}
+	} else
+		/* after lookup_chain_cache(): */
+		if (unlikely(!debug_locks))
+			return 0;
+
 	curr->lockdep_depth++;
 	check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	if (unlikely(!debug_locks))
+		return 0;
+#endif
 	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
 		debug_locks_off();
 		printk("BUG: MAX_LOCK_DEPTH too low!\n");
 		printk("turning off the locking correctness validator.\n");
 		return 0;
 	}
+
 	if (unlikely(curr->lockdep_depth > max_lockdep_depth))
 		max_lockdep_depth = curr->lockdep_depth;
 
@@ -2577,7 +2602,7 @@ out_restore:
 	raw_local_irq_restore(flags);
 }
 
-void __init lockdep_init(void)
+void lockdep_init(void)
 {
 	int i;
 
@@ -2717,6 +2742,10 @@ void debug_show_all_locks(void)
 	int count = 10;
 	int unlock = 1;
 
+	if (unlikely(!debug_locks)) {
+		printk("INFO: lockdep is turned off.\n");
+		return;
+	}
 	printk("\nShowing all locks held in the system:\n");
 
 	/*
@@ -2760,8 +2789,11 @@ EXPORT_SYMBOL_GPL(debug_show_all_locks);
 
 void debug_show_held_locks(struct task_struct *task)
 {
+	if (unlikely(!debug_locks)) {
+		printk("INFO: lockdep is turned off.\n");
+		return;
+	}
 	lockdep_print_held_locks(task);
 }
 
 EXPORT_SYMBOL_GPL(debug_show_held_locks);
-