staging: comedi: pcl812: use comedi_legacy_detach()

This driver does not follow the standard (*attach) (*detach) flow of
the other drivers in comedi. Comedi drivers do not 'cleanup' any of
the allocations made during the (*attach) if failures are encountered.
If the (*attach) fails, the comedi core will call the (*detach) to
handle any clenaup.

In this driver, the function free_resources() handles all the cleanup.
Remove the calls to this function during the (*attach). Since the
(*detach) is then the only caller, remove the function and just put
all the cleanup in the (*detach) function.

Use the new comedi_legacy_detach() helper in the (*detach) to release
the I/O region.

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>

drivers/staging/comedi/drivers/pcl812.c

@@ -1038,28 +1038,6 @@ static void start_pacer(struct comedi_device *dev, int mode,
 	}
 }
 
-/*
-==============================================================================
-*/
-static void free_resources(struct comedi_device *dev)
-{
-	const struct pcl812_board *board = comedi_board(dev);
-	struct pcl812_private *devpriv = dev->private;
-
-	if (devpriv) {
-		if (devpriv->dmabuf[0])
-			free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]);
-		if (devpriv->dmabuf[1])
-			free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]);
-		if (devpriv->dma)
-			free_dma(devpriv->dma);
-	}
-	if (dev->irq)
-		free_irq(dev->irq, dev);
-	if (dev->iobase)
-		release_region(dev->iobase, board->io_range);
-}
-
 /*
 ==============================================================================
 */
@@ -1133,10 +1111,8 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 		return ret;
 
 	devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
-	if (!devpriv) {
-		free_resources(dev);
+	if (!devpriv)
 		return -ENOMEM;
-	}
 	dev->private = devpriv;
 
 	irq = 0;
@@ -1190,7 +1166,6 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 			 * maybe experiment with try_to_free_pages()
 			 * will help ....
 			 */
-			free_resources(dev);
 			return -EBUSY;	/* no buffer :-( */
 		}
 		devpriv->dmapages[0] = pages;
@@ -1199,7 +1174,6 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 		devpriv->dmabuf[1] = __get_dma_pages(GFP_KERNEL, pages);
 		if (!devpriv->dmabuf[1]) {
 			printk(KERN_ERR ", unable to allocate DMA buffer, FAIL!\n");
-			free_resources(dev);
 			return -EBUSY;
 		}
 		devpriv->dmapages[1] = pages;
@@ -1219,10 +1193,8 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 		n_subdevices++;
 
 	ret = comedi_alloc_subdevices(dev, n_subdevices);
-	if (ret) {
-		free_resources(dev);
+	if (ret)
 		return ret;
-	}
 
 	subdev = 0;
 
@@ -1456,7 +1428,19 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 
 static void pcl812_detach(struct comedi_device *dev)
 {
-	free_resources(dev);
+	struct pcl812_private *devpriv = dev->private;
+
+	if (devpriv) {
+		if (devpriv->dmabuf[0])
+			free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]);
+		if (devpriv->dmabuf[1])
+			free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]);
+		if (devpriv->dma)
+			free_dma(devpriv->dma);
+	}
+	if (dev->irq)
+		free_irq(dev->irq, dev);
+	comedi_legacy_detach(dev);
 }
 
 static const struct pcl812_board boardtypes[] = {