When attaching a PCI device manually via the comedi driver `attach` hook
(`dio200_attach()`) (called by the comedi core for the
`COMEDI_DEVCONFIG` ioctl), its reference count is incremented in the
`for_each_pci_dev` loop (in `dio200_find_pci_dev()`).  It is decremented
when the `detach` hook (`dio200_detach()`) is called to detach the
device.  However, when the PCI device is attached automatically via the
`attach_pci` hook (`dio200_attach_pci()`, called at probe time via
`comedi_pci_auto_config()`) it's reference count is not incremented so
there will be an unmatched decrement when detaching the device.

Increment the PCI device reference count in `dio200_attach_pci()` to
correct the mismatch.

Once support for manual configuration has been removed from this driver,
the calls to `pci_dev_get()` and `pci_dev_put()` can be removed.

Signed-off-by: Ian Abbott <[email protected]>
---
 drivers/staging/comedi/drivers/amplc_dio200.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/staging/comedi/drivers/amplc_dio200.c 
b/drivers/staging/comedi/drivers/amplc_dio200.c
index 9c8fbf1..5858892 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200.c
@@ -1421,6 +1421,13 @@ static int __devinit dio200_attach_pci(struct 
comedi_device *dev,
                dev_err(dev->class_dev, "BUG! cannot determine board type!\n");
                return -EINVAL;
        }
+       /*
+        * Need to 'get' the PCI device to match the 'put' in dio200_detach().
+        * TODO: Remove the pci_dev_get() and matching pci_dev_put() once
+        * support for manual attachment of PCI devices via dio200_attach()
+        * has been removed.
+        */
+       pci_dev_get(pci_dev);
        return dio200_pci_common_attach(dev, pci_dev);
 }
 
-- 
1.7.12

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