I/OAT: clean up of dca provider start and stop

Don't start ioat_dca if ioat_dma didn't start, and then stop ioat_dca
before stopping ioat_dma.  Since the ioat_dma side does the pci device
work, This takes care of ioat_dca trying to use a bad device reference.
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/dma/ioat.c

@@ -71,7 +71,7 @@ static int ioat_setup_functionality(struct pci_dev *pdev, void __iomem *iobase)
 	switch (version) {
 	case IOAT_VER_1_2:
 		device->dma = ioat_dma_probe(pdev, iobase);
-		if (ioat_dca_enabled)
+		if (device->dma && ioat_dca_enabled)
 			device->dca = ioat_dca_init(pdev, iobase);
 		break;
 	default:
@@ -85,17 +85,16 @@ static void ioat_shutdown_functionality(struct pci_dev *pdev)
 {
 	struct ioat_device *device = pci_get_drvdata(pdev);
 
-	if (device->dma) {
-		ioat_dma_remove(device->dma);
-		device->dma = NULL;
-	}
-
 	if (device->dca) {
 		unregister_dca_provider(device->dca);
 		free_dca_provider(device->dca);
 		device->dca = NULL;
 	}
 
+	if (device->dma) {
+		ioat_dma_remove(device->dma);
+		device->dma = NULL;
+	}
 }
 
 static struct pci_driver ioat_pci_driver = {

drivers/dma/ioat_dma.c

@@ -941,10 +941,10 @@ void ioat_dma_remove(struct ioatdma_device *device)
 	struct dma_chan *chan, *_chan;
 	struct ioat_dma_chan *ioat_chan;
 
-	dma_async_device_unregister(&device->common);
-
 	ioat_dma_remove_interrupts(device);
 
+	dma_async_device_unregister(&device->common);
+
 	pci_pool_destroy(device->dma_pool);
 	pci_pool_destroy(device->completion_pool);