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Commit a649a675 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: adjust module count on device cleanup 



`comedi_device_cleanup()` is called just before freeing a comedi device.
It is possible for the device to still be open in which case the module
reference counts for the core comedi module and possibly the low-level
driver module will remain out of whack because `comedi_close()` will not
find the comedi device and so will not decrement the module counts.

This really needs to be handled better, but for now decrement the module
counts in `comedi_device_cleanup()` according to the number of
outstanding opens.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Reviewed-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4ca7da6e

drivers/staging/comedi/comedi_fops.c

+10 −0
Original line number Diff line number Diff line
@@ -2256,10 +2256,20 @@ static void comedi_device_init(struct comedi_device *dev) 


static void comedi_device_cleanup(struct comedi_device *dev)

{

	struct module *driver_module = NULL;



	if (dev == NULL)

		return;

	mutex_lock(&dev->mutex);

	if (dev->attached)

		driver_module = dev->driver->module;

	comedi_device_detach(dev);

	while (dev->use_count > 0) {

		if (driver_module)

			module_put(driver_module);

		module_put(THIS_MODULE);

		dev->use_count--;

	}

	mutex_unlock(&dev->mutex);

	mutex_destroy(&dev->mutex);

}