staging: comedi: jr3_pci: check PCI BAR 0 size

The various supported boards have different numbers of subdevices from 1
to 4.  Each subdevice needs a block of registers in PCI BAR 0.  Check
the region is large enough for the required number of subdevices.
Return an error from `jr3_pci_auto_attach()` if it is too small.

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

drivers/staging/comedi/drivers/jr3_pci.c

@@ -705,6 +705,9 @@ static int jr3_pci_auto_attach(struct comedi_device *dev,
 	if (ret)
 		return ret;
 
+	if (pci_resource_len(pcidev, 0) < board->n_subdevs * sizeof(*block))
+		return -ENXIO;
+
 	dev->mmio = pci_ioremap_bar(pcidev, 0);
 	if (!dev->mmio)
 		return -ENOMEM;