debugobjects: Move printk out of db->lock critical sections

The db->lock is a raw spinlock and so the lock hold time is supposed to be short. This will not be the case when printk() is being involved in some of the critical sections. In order to avoid the long hold time, in case some messages need to be printed, the debug_object_is_on_stack() and debug_print_object() calls are now moved out of those critical sections.

Waiman Long committed 7 years ago

Commit d5f34151 parent a7344a61 file · +39 −19Browse files

Showing the changes to lib/debugobjects.c (1 of 1 file). Show all

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lib/debugobjects.c+39−19

 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 {
 	enum debug_obj_state state;
+	bool check_stack = false;
 	struct debug_bucket *db;
 	struct debug_obj *obj;
 	unsigned long flags;
 			debug_objects_oom();
 			return;
 		}
-		debug_object_is_on_stack(addr, onstack);
+		check_stack = true;
 	}
 	switch (obj->state) {
 		break;
 	case ODEBUG_STATE_ACTIVE:
-		debug_print_object(obj, "init");
 		state = obj->state;
 		raw_spin_unlock_irqrestore(&db->lock, flags);
+		debug_print_object(obj, "init");
 		debug_object_fixup(descr->fixup_init, addr, state);
 		return;
 	case ODEBUG_STATE_DESTROYED:
+		raw_spin_unlock_irqrestore(&db->lock, flags);
 		debug_print_object(obj, "init");
-		break;
+		return;
 	default:
 		break;
 	}
 	raw_spin_unlock_irqrestore(&db->lock, flags);
+	if (check_stack)
+		debug_object_is_on_stack(addr, onstack);
 }
 /**
 	obj = lookup_object(addr, db);
 	if (obj) {
+		bool print_object = false;
 		switch (obj->state) {
 		case ODEBUG_STATE_INIT:
 		case ODEBUG_STATE_INACTIVE:
 			break;
 		case ODEBUG_STATE_ACTIVE:
-			debug_print_object(obj, "activate");
 			state = obj->state;
 			raw_spin_unlock_irqrestore(&db->lock, flags);
+			debug_print_object(obj, "activate");
 			ret = debug_object_fixup(descr->fixup_activate, addr, state);
 			return ret ? 0 : -EINVAL;
 		case ODEBUG_STATE_DESTROYED:
-			debug_print_object(obj, "activate");
+			print_object = true;
 			ret = -EINVAL;
 			break;
 		default:
 			break;
 		}
 		raw_spin_unlock_irqrestore(&db->lock, flags);
+		if (print_object)
+			debug_print_object(obj, "activate");
 		return ret;
 	}
 	raw_spin_unlock_irqrestore(&db->lock, flags);
 	/*
 	 * We are here when a static object is activated. We
 	 * let the type specific code confirm whether this is
 	struct debug_bucket *db;
 	struct debug_obj *obj;
 	unsigned long flags;
+	bool print_object = false;
 	if (!debug_objects_enabled)
 		return;
 			if (!obj->astate)
 				obj->state = ODEBUG_STATE_INACTIVE;
 			else
-				debug_print_object(obj, "deactivate");
+				print_object = true;
 			break;
 		case ODEBUG_STATE_DESTROYED:
-			debug_print_object(obj, "deactivate");
+			print_object = true;
 			break;
 		default:
 			break;
 		}
-	} else {
+	}
+	raw_spin_unlock_irqrestore(&db->lock, flags);
+	if (!obj) {
 		struct debug_obj o = { .object = addr,
 				       .state = ODEBUG_STATE_NOTAVAILABLE,
 				       .descr = descr };
 		debug_print_object(&o, "deactivate");
+	} else if (print_object) {
+		debug_print_object(obj, "deactivate");
 	}
-	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 	struct debug_bucket *db;
 	struct debug_obj *obj;
 	unsigned long flags;
+	bool print_object = false;
 	if (!debug_objects_enabled)
 		return;
 		obj->state = ODEBUG_STATE_DESTROYED;
 		break;
 	case ODEBUG_STATE_ACTIVE:
-		debug_print_object(obj, "destroy");
 		state = obj->state;
 		raw_spin_unlock_irqrestore(&db->lock, flags);
+		debug_print_object(obj, "destroy");
 		debug_object_fixup(descr->fixup_destroy, addr, state);
 		return;
 	case ODEBUG_STATE_DESTROYED:
-		debug_print_object(obj, "destroy");
+		print_object = true;
 		break;
 	default:
 		break;
 	}
 out_unlock:
 	raw_spin_unlock_irqrestore(&db->lock, flags);
+	if (print_object)
+		debug_print_object(obj, "destroy");
 }
 EXPORT_SYMBOL_GPL(debug_object_destroy);
 	switch (obj->state) {
 	case ODEBUG_STATE_ACTIVE:
-		debug_print_object(obj, "free");
 		state = obj->state;
 		raw_spin_unlock_irqrestore(&db->lock, flags);
+		debug_print_object(obj, "free");
 		debug_object_fixup(descr->fixup_free, addr, state);
 		return;
 	default:
 	struct debug_bucket *db;
 	struct debug_obj *obj;
 	unsigned long flags;
+	bool print_object = false;
 	if (!debug_objects_enabled)
 		return;
 			if (obj->astate == expect)
 				obj->astate = next;
 			else
-				debug_print_object(obj, "active_state");
+				print_object = true;
 			break;
 		default:
-			debug_print_object(obj, "active_state");
+			print_object = true;
 			break;
 		}
-	} else {
+	}
+	raw_spin_unlock_irqrestore(&db->lock, flags);
+	if (!obj) {
 		struct debug_obj o = { .object = addr,
 				       .state = ODEBUG_STATE_NOTAVAILABLE,
 				       .descr = descr };
 		debug_print_object(&o, "active_state");
+	} else if (print_object) {
+		debug_print_object(obj, "active_state");
 	}
-	raw_spin_unlock_irqrestore(&db->lock, flags);
 }
 EXPORT_SYMBOL_GPL(debug_object_active_state);
 			switch (obj->state) {
 			case ODEBUG_STATE_ACTIVE:
-				debug_print_object(obj, "free");
 				descr = obj->descr;
 				state = obj->state;
 				raw_spin_unlock_irqrestore(&db->lock, flags);
+				debug_print_object(obj, "free");
 				debug_object_fixup(descr->fixup_free,
 						   (void *) oaddr, state);
 				goto repeat;