From: Ian Abbott <abbotti@mev.co.uk>
Date: Mon, 3 Sep 2012 15:39:41 +0000 (+0100)
Subject: staging: comedi: amplc_pc263: Fix PCI ref count
X-Git-Tag: firefly_0821_release~3680^2~2098^2~13
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a0234ade63ce2c14841d9d6e802ed735b4ed2829;p=firefly-linux-kernel-4.4.55.git

staging: comedi: amplc_pc263: Fix PCI ref count

When attaching a PCI device manually via the comedi driver `attach` hook
(`pc263_attach()`) (called by the comedi core for the `COMEDI_DEVCONFIG`
ioctl), its reference count is incremented in the `for_each_pci_dev`
loop (in `pc263_find_pci_dev()`).  It is decremented when the `detach`
hook (`pc263_detach()`) is called to detach the device.  However, when
the PCI device is attached automatically via the `attach_pci` hook
(`pc263_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 `pc263_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>
---

diff --git a/drivers/staging/comedi/drivers/amplc_pc263.c b/drivers/staging/comedi/drivers/amplc_pc263.c
index 40ec1ffebba6..8191c4e28e0a 100644
--- a/drivers/staging/comedi/drivers/amplc_pc263.c
+++ b/drivers/staging/comedi/drivers/amplc_pc263.c
@@ -298,6 +298,13 @@ static int __devinit pc263_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 pc263_detach().
+	 * TODO: Remove the pci_dev_get() and matching pci_dev_put() once
+	 * support for manual attachment of PCI devices via pc263_attach()
+	 * has been removed.
+	 */
+	pci_dev_get(pci_dev);
 	return pc263_pci_common_attach(dev, pci_dev);
 }