staging: comedi: amplc_dio200_common: prevent extra free_irq()

`dio200_detach()` in "amplc_dio200.c" calls
`amplc_dio200_common_detach()` in "amplc_dio200_common.c", followed by
`comedi_legacy_detach()` in "../drivers.c".  Both of those functions
call `free_irq()` if `dev->irq` is non-zero.  The second call produces a
warning message because the handler has already been freed.  Prevent
that by setting `dev->irq = 0` in `amplc_dio200_common_detach()`.

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>

diff --git a/drivers/staging/comedi/drivers/amplc_dio200_common.c b/drivers/staging/comedi/drivers/amplc_dio200_common.c
index 78700e8185ed7ba613ca52aac54bd7232214763e..3592e58c57d5c5462f80657ca5e7ac7be86178d5 100644 (file)
--- a/drivers/staging/comedi/drivers/amplc_dio200_common.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200_common.c
@@ -1202,8 +1202,10 @@ void amplc_dio200_common_detach(struct comedi_device *dev)
 
        if (!thisboard || !devpriv)
                return;
-       if (dev->irq)
+       if (dev->irq) {
                free_irq(dev->irq, dev);
+               dev->irq = 0;
+       }
 }
 EXPORT_SYMBOL_GPL(amplc_dio200_common_detach);