[PATCH 3/6] staging: comedi: amplc_pc236: Fix PCI ref count

Ian Abbott abbotti at mev.co.uk
Mon Sep 3 15:39:40 UTC 2012


When attaching a PCI device manually via the comedi driver `attach` hook
(`pc236_attach()`) (called by the comedi core for the `COMEDI_DEVCONFIG`
ioctl), its reference count is incremented in the `for_each_pci_dev`
loop (in `pc236_find_pci_dev()`).  It is decremented when the `detach`
hook (`pc236_detach()`) is called to detach the device.  However, when
the PCI device is attached automatically via the `attach_pci` hook
(`pc236_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 `pc236_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 at mev.co.uk>
---
 drivers/staging/comedi/drivers/amplc_pc236.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c
index c644385..52f7575 100644
--- a/drivers/staging/comedi/drivers/amplc_pc236.c
+++ b/drivers/staging/comedi/drivers/amplc_pc236.c
@@ -578,6 +578,13 @@ static int __devinit pc236_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 pc236_detach().
+	 * TODO: Remove the pci_dev_get() and matching pci_dev_put() once
+	 * support for manual attachment of PCI devices via pc236_attach()
+	 * has been removed.
+	 */
+	pci_dev_get(pci_dev);
 	return pc236_pci_common_attach(dev, pci_dev);
 }
 
-- 
1.7.12




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