From 7be7cd10ade121cd5363c5f8790638b177b5e9dd Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Wed, 30 Mar 2016 10:47:25 -0700 Subject: [PATCH] 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 Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index e3bbc8f724ba..44511d729450 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -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) -- 2.20.1