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Subject[ 063/262] staging: comedi: amplc_pci224: Fix PCI ref count
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.5-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ian Abbott <abbotti@mev.co.uk>

commit cadf84bfeb80e216fde328d357fe856160157d2c upstream.

When attaching a PCI device manually via the comedi driver `attach` hook
(`pci224_attach()`) (called by the comedi core for the
`COMEDI_DEVCONFIG` ioctl), its reference count is incremented in the
`for_each_pci_dev` loop (in `pci224_find_pci_dev()`). It is decremented
when the `detach` hook (`pci224_detach()`) is called to detach the
device. However, when the PCI device is attached automatically via the
`attach_pci` hook (`pci224_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 `pci224_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 <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/comedi/drivers/amplc_pci224.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/drivers/staging/comedi/drivers/amplc_pci224.c
+++ b/drivers/staging/comedi/drivers/amplc_pci224.c
@@ -1519,6 +1519,13 @@ pci224_attach_pci(struct comedi_device *
dev->minor, DRIVER_NAME);
return -EINVAL;
}
+ /*
+ * Need to 'get' the PCI device to match the 'put' in pci224_detach().
+ * TODO: Remove the pci_dev_get() and matching pci_dev_put() once
+ * support for manual attachment of PCI devices via pci224_attach()
+ * has been removed.
+ */
+ pci_dev_get(pci_dev);
return pci224_attach_common(dev, pci_dev, NULL);
}




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