staging: comedi: comedi_pci: introduce comedi_pci_detach()

Introduce a generic (*detach) function for comedi PCI drivers to handle
the boilerplate code needed to detach a PCI driver.

This function works similar to comedi_legacy_detach() where it will:

  * free the dev->irq if it has been requested
  * iounmap the dev->mmio addres if it has been ioremap'ed

The helper then calls comedi_pci_disable() to release the regions and
disable the PCI device.

Use the new helper directly for the (*detach) in the following cases:

  * where comedi_pci_disable() is used directly for the (*detach)
  * where the detach function is just boilerplate

Use the new helper in the (*detach) of the simpler PCI drivers. Call
the helper after disabling interrupts (reset) and before any additional
cleanup (kfree) to avoid any race conditions with the interrupt handler.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/staging/comedi/comedi_pci.c b/drivers/staging/comedi/comedi_pci.c
index abbc0e4f5c51..aa0795a2660e 100644
--- a/drivers/staging/comedi/comedi_pci.c
+++ b/drivers/staging/comedi/comedi_pci.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/pci.h>
+#include <linux/interrupt.h>
 
 #include "comedidev.h"
 
@@ -73,6 +74,29 @@ void comedi_pci_disable(struct comedi_device *dev)
 EXPORT_SYMBOL_GPL(comedi_pci_disable);
 
 /**
+ * comedi_pci_detach() - A generic (*detach) function for PCI drivers.
+ * @dev: comedi_device struct
+ */
+void comedi_pci_detach(struct comedi_device *dev)
+{
+	struct pci_dev *pcidev = comedi_to_pci_dev(dev);
+
+	if (!pcidev || !dev->ioenabled)
+		return;
+
+	if (dev->irq) {
+		free_irq(dev->irq, dev);
+		dev->irq = 0;
+	}
+	if (dev->mmio) {
+		iounmap(dev->mmio);
+		dev->mmio = NULL;
+	}
+	comedi_pci_disable(dev);
+}
+EXPORT_SYMBOL_GPL(comedi_pci_detach);
+
+/**
  * comedi_pci_auto_config() - Configure/probe a comedi PCI driver.
  * @pcidev: pci_dev struct
  * @driver: comedi_driver struct