gpu: host1x: Use different lock classes for each client

To avoid false lockdep warnings, give each client lock a different
lock class, passed from the initialization site by macro.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/bus.c

@@ -705,8 +705,9 @@ void host1x_driver_unregister(struct host1x_driver *driver)
 EXPORT_SYMBOL(host1x_driver_unregister);
 
 /**
- * host1x_client_register() - register a host1x client
+ * __host1x_client_register() - register a host1x client
  * @client: host1x client
+ * @key: lock class key for the client-specific mutex
  *
  * Registers a host1x client with each host1x controller instance. Note that
  * each client will only match their parent host1x controller and will only be
@@ -715,13 +716,14 @@ EXPORT_SYMBOL(host1x_driver_unregister);
  * device and call host1x_device_init(), which will in turn call each client's
  * &host1x_client_ops.init implementation.
  */
-int host1x_client_register(struct host1x_client *client)
+int __host1x_client_register(struct host1x_client *client,
+			     struct lock_class_key *key)
 {
 	struct host1x *host1x;
 	int err;
 
 	INIT_LIST_HEAD(&client->list);
-	mutex_init(&client->lock);
+	__mutex_init(&client->lock, "host1x client lock", key);
 	client->usecount = 0;
 
 	mutex_lock(&devices_lock);
@@ -742,7 +744,7 @@ int host1x_client_register(struct host1x_client *client)
 
 	return 0;
 }
-EXPORT_SYMBOL(host1x_client_register);
+EXPORT_SYMBOL(__host1x_client_register);
 
 /**
  * host1x_client_unregister() - unregister a host1x client

include/linux/host1x.h

@@ -320,7 +320,14 @@ static inline struct host1x_device *to_host1x_device(struct device *dev)
 int host1x_device_init(struct host1x_device *device);
 int host1x_device_exit(struct host1x_device *device);
 
-int host1x_client_register(struct host1x_client *client);
+int __host1x_client_register(struct host1x_client *client,
+			     struct lock_class_key *key);
+#define host1x_client_register(class) \
+	({ \
+		static struct lock_class_key __key; \
+		__host1x_client_register(class, &__key); \
+	})
+
 int host1x_client_unregister(struct host1x_client *client);
 
 int host1x_client_suspend(struct host1x_client *client);