staging: comedi: Add lockdep_assert_held() calls for dev->attach_lock

There are not a lot of functions in the core comedi module that require
the R/W semaphore `attach_lock` in `struct comedi_device` to be locked
(although there are a few functions that require at least one of
`attach_lock` and `mutex` to be locked).  One function that requires the
caller to lock `attach_lock` is `comedi_device_detach_cleanup()` so add
a call to `lockdep_assert_held()` to check and document that.

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

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index fdf0a57..750a6ff 100644 (file)
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -159,6 +159,7 @@ static void comedi_device_detach_cleanup(struct comedi_device *dev)
        int i;
        struct comedi_subdevice *s;
 
+       lockdep_assert_held(&dev->attach_lock);
        lockdep_assert_held(&dev->mutex);
        if (dev->subdevices) {
                for (i = 0; i < dev->n_subdevices; i++) {