staging: comedi: Add lockdep_assert_held() calls for dev->mutex

Lots of functions in the core comedi module expect the mutex in `struct
comedi_device` to be held, so add calls to `lockdep_assert_held()` to
check and document that.  An unusual case is the calls to
`lockdep_assert_held()` after successful return from
`comedi_alloc_board_minor()` which allocates a `struct comedi_device`
and returns with its mutex locked.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index b7b9e48d4303..fdf0a5761f9b 100644
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -159,6 +159,7 @@ static void comedi_device_detach_cleanup(struct comedi_device *dev)
 	int i;
 	struct comedi_subdevice *s;
 
+	lockdep_assert_held(&dev->mutex);
 	if (dev->subdevices) {
 		for (i = 0; i < dev->n_subdevices; i++) {
 			s = &dev->subdevices[i];
@@ -196,6 +197,7 @@ static void comedi_device_detach_cleanup(struct comedi_device *dev)
 
 void comedi_device_detach(struct comedi_device *dev)
 {
+	lockdep_assert_held(&dev->mutex);
 	comedi_device_cancel_all(dev);
 	down_write(&dev->attach_lock);
 	dev->attached = false;
@@ -643,6 +645,7 @@ static int __comedi_device_postconfig_async(struct comedi_device *dev,
 	unsigned int buf_size;
 	int ret;
 
+	lockdep_assert_held(&dev->mutex);
 	if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
 		dev_warn(dev->class_dev,
 			 "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
@@ -690,6 +693,7 @@ static int __comedi_device_postconfig(struct comedi_device *dev)
 	int ret;
 	int i;
 
+	lockdep_assert_held(&dev->mutex);
 	if (!dev->insn_device_config)
 		dev->insn_device_config = insn_device_inval;
 
@@ -747,6 +751,7 @@ static int comedi_device_postconfig(struct comedi_device *dev)
 {
 	int ret;
 
+	lockdep_assert_held(&dev->mutex);
 	ret = __comedi_device_postconfig(dev);
 	if (ret < 0)
 		return ret;
@@ -946,6 +951,7 @@ int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	struct comedi_driver *driv;
 	int ret;
 
+	lockdep_assert_held(&dev->mutex);
 	if (dev->attached)
 		return -EBUSY;
 
@@ -1053,6 +1059,7 @@ int comedi_auto_config(struct device *hardware_device,
 		return PTR_ERR(dev);
 	}
 	/* Note: comedi_alloc_board_minor() locked dev->mutex. */
+	lockdep_assert_held(&dev->mutex);
 
 	dev->driver = driver;
 	dev->board_name = dev->driver->driver_name;