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>
diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index e3bbc8f..44511d7 100644
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -564,7 +564,7 @@
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 @@
"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)