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staging: comedi: drivers: fix possible bug in comedi_handle_events()

This function assumes that the async subdevice has a cancel() function.
It looks like all the current comedi drivers implement a cancel() for
the async subdevices except for the dt2814 analog input usbdevice.

Fix comedi_handle_events() so it does not try to call a non-existent
cancel() function.

Add a dev_warn() to __comedi_device_postconfig_async() so that any new
driver authors will be reminded to implement the cancel().

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2016-03-30 10:47:25 -07:00 committed by Greg Kroah-Hartman
parent f91852ce61
commit 7be7cd10ad

View File

@ -564,7 +564,7 @@ unsigned int comedi_handle_events(struct comedi_device *dev,
if (events == 0)
return events;
if (events & COMEDI_CB_CANCEL_MASK)
if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
s->cancel(dev, s);
comedi_event(dev, s);
@ -625,6 +625,9 @@ static int __comedi_device_postconfig_async(struct comedi_device *dev,
"async subdevices must have a do_cmdtest() function\n");
return -EINVAL;
}
if (!s->cancel)
dev_warn(dev->class_dev,
"async subdevices should have a cancel() function\n");
async = kzalloc(sizeof(*async), GFP_KERNEL);
if (!async)