`comedi_event()` is called from low-level drivers to handle asynchronous
command event flags that are stored in `s->async->events` for subdevice
`s`. It normally clears the event flags as well. As a safety check, it
does nothing if no asynchronous command is running, but it leaves
`s->async->events` unchanged in this case. For additional safety,
change it to always clear the event flags to avoid leaving stale event
flags set when another asynchronous command is set up.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/comedi_fops.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 999e7d0..68ced20 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2648,18 +2648,20 @@ void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
struct comedi_async *async = s->async;
unsigned runflags = 0;
unsigned runflags_mask = 0;
+ unsigned int events = async->events;
+ async->events = 0;
if (!comedi_is_subdevice_running(s))
return;
- if (async->events & COMEDI_CB_CANCEL_MASK)
+ if (events & COMEDI_CB_CANCEL_MASK)
runflags_mask |= COMEDI_SRF_RUNNING;
/*
* Remember if an error event has occurred, so an error
* can be returned the next time the user does a read().
*/
- if (async->events & COMEDI_CB_ERROR_MASK) {
+ if (events & COMEDI_CB_ERROR_MASK) {
runflags_mask |= COMEDI_SRF_ERROR;
runflags |= COMEDI_SRF_ERROR;
}
@@ -2671,14 +2673,13 @@ void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
comedi_update_subdevice_runflags(s, runflags_mask, runflags);
}
- if (async->cb_mask & async->events) {
+ if (async->cb_mask & events) {
wake_up_interruptible(&async->wait_head);
if (s->subdev_flags & SDF_CMD_READ)
kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
if (s->subdev_flags & SDF_CMD_WRITE)
kill_fasync(&dev->async_queue, SIGIO, POLL_OUT);
}
- async->events = 0;
}
EXPORT_SYMBOL_GPL(comedi_event);
--
2.1.4
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