staging: comedi: cancel commands before detaching device

The comedi core module's handling of the `COMEDI_DEVCONFIG` ioctl will
not allow a device to be detached if it is busy.  However, comedi
devices can also be auto-detached due to a removal of a hardware device.
One of the things we should do in that case is cancel any asynchronous
commands that are running.  Add a new function
`comedi_device_cancel_all()` to do that and call it from
`comedi_device_detach()`.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 9c85f01e847bc244ec5c6755bf45c9c9765fb2ae..eafa18efdeeaeb645aa186e1e9885ae060e1c326 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -584,6 +584,21 @@ static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
        return ret;
 }
 
+void comedi_device_cancel_all(struct comedi_device *dev)
+{
+       struct comedi_subdevice *s;
+       int i;
+
+       if (!dev->attached)
+               return;
+
+       for (i = 0; i < dev->n_subdevices; i++) {
+               s = &dev->subdevices[i];
+               if (s->async)
+                       do_cancel(dev, s);
+       }
+}
+
 static int is_device_busy(struct comedi_device *dev)
 {
        struct comedi_subdevice *s;

diff --git a/drivers/staging/comedi/comedi_internal.h b/drivers/staging/comedi/comedi_internal.h
index fda1a7ba0e16bb83cec7f5bb21eb9347971a7628..151693b1138331d71f91e4cadacb694150d14375 100644 (file)
--- a/drivers/staging/comedi/comedi_internal.h
+++ b/drivers/staging/comedi/comedi_internal.h
@@ -17,6 +17,7 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
                     unsigned long new_size);
 void comedi_buf_reset(struct comedi_async *async);
 unsigned int comedi_buf_write_n_allocated(struct comedi_async *async);
+void comedi_device_cancel_all(struct comedi_device *dev);
 
 extern unsigned int comedi_default_buf_size_kb;
 extern unsigned int comedi_default_buf_maxsize_kb;

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index 1f44f2939f6af4d7a5132953139f4d42f33d3a94..4f727731a72d35ceabfc9a5107fc1ec651fc1a16 100644 (file)
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -133,6 +133,7 @@ static void comedi_device_detach_cleanup(struct comedi_device *dev)
 
 void comedi_device_detach(struct comedi_device *dev)
 {
+       comedi_device_cancel_all(dev);
        down_write(&dev->attach_lock);
        dev->attached = false;
        if (dev->driver)