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staging: comedi: comedi_fops: always clear events

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`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@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2015-03-27 15:13:04 +00:00 • committed by Greg Kroah-Hartman
parent 258c1dd76b
commit 922d9ced71
1 changed files with 5 additions and 4 deletions
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9
drivers/staging/comedi/comedi_fops.c
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@ -2648,18 +2648,20 @@ void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
struct comedi_async *async = s->async; struct comedi_async *async = s->async;
unsigned runflags = 0; unsigned runflags = 0;
unsigned runflags_mask = 0; unsigned runflags_mask = 0;
unsigned int events = async->events;
async->events = 0;
if (!comedi_is_subdevice_running(s)) if (!comedi_is_subdevice_running(s))
return; return;
if (async->events & COMEDI_CB_CANCEL_MASK) if (events & COMEDI_CB_CANCEL_MASK)
runflags_mask |= COMEDI_SRF_RUNNING; runflags_mask |= COMEDI_SRF_RUNNING;
/* /*
* Remember if an error event has occurred, so an error * Remember if an error event has occurred, so an error
* can be returned the next time the user does a read(). * 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_mask |= COMEDI_SRF_ERROR;
runflags |= 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); 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); wake_up_interruptible(&async->wait_head);
if (s->subdev_flags & SDF_CMD_READ) if (s->subdev_flags & SDF_CMD_READ)
kill_fasync(&dev->async_queue, SIGIO, POLL_IN); kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
if (s->subdev_flags & SDF_CMD_WRITE) if (s->subdev_flags & SDF_CMD_WRITE)
kill_fasync(&dev->async_queue, SIGIO, POLL_OUT); kill_fasync(&dev->async_queue, SIGIO, POLL_OUT);
} }
async->events = 0;
} }
EXPORT_SYMBOL_GPL(comedi_event); EXPORT_SYMBOL_GPL(comedi_event);