From 922d9ced718268e464a0884ecee09da436e00d70 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 27 Mar 2015 15:13:04 +0000 Subject: [PATCH] staging: comedi: comedi_fops: always clear events `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 Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- 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 999e7d010c83..68ced20f5ca5 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); -- 2.30.2