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Commit de06d7c6 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: restrict comedi_set_hw_dev() usage 



Don't allow comedi drivers to change `dev->hw_dev` using
`comedi_set_hw_dev()` if it's already been set.  Return `-EEXIST` in
that case.

`dev->hw_dev` needs to be set to NULL by the core during clean-up of the
comedi device, so add a local function `comedi_clear_hw_dev()` to do
that.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da717511

drivers/staging/comedi/drivers.c

+11 −4
Original line number Original line Diff line number Diff line
@@ -45,14 +45,21 @@ struct comedi_driver *comedi_drivers; 




int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)

int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)

{

{

	struct device *old_hw_dev = dev->hw_dev;

	if (hw_dev == dev->hw_dev)



		return 0;

	if (dev->hw_dev != NULL)

		return -EEXIST;

	dev->hw_dev = get_device(hw_dev);

	dev->hw_dev = get_device(hw_dev);

	put_device(old_hw_dev);

	return 0;

	return 0;

}

}

EXPORT_SYMBOL_GPL(comedi_set_hw_dev);

EXPORT_SYMBOL_GPL(comedi_set_hw_dev);





static void comedi_clear_hw_dev(struct comedi_device *dev)

{

	put_device(dev->hw_dev);

	dev->hw_dev = NULL;

}



int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)

int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)

{

{

	struct comedi_subdevice *s;

	struct comedi_subdevice *s;
@@ -108,7 +115,7 @@ static void cleanup_device(struct comedi_device *dev) 
	dev->write_subdev = NULL;

	dev->write_subdev = NULL;

	dev->open = NULL;

	dev->open = NULL;

	dev->close = NULL;

	dev->close = NULL;

	comedi_set_hw_dev(dev, NULL);

	comedi_clear_hw_dev(dev);

}

}





static void __comedi_device_detach(struct comedi_device *dev)

static void __comedi_device_detach(struct comedi_device *dev)