igc: Improve the DMA mapping flow

Improve the probe flow and set both the DMA mask and the coherent
to the same thing. Make the flow optimized and cleared.
Signed-off-by: NSasha Neftin <sasha.neftin@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igc/igc_main.c

@@ -4345,32 +4345,26 @@ static int igc_probe(struct pci_dev *pdev,
 	struct net_device *netdev;
 	struct igc_hw *hw;
 	const struct igc_info *ei = igc_info_tbl[ent->driver_data];
-	int err;
+	int err, pci_using_dac;
 
 	err = pci_enable_device_mem(pdev);
 	if (err)
 		return err;
 
-	err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
+	pci_using_dac = 0;
+	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
 	if (!err) {
-		err = dma_set_coherent_mask(&pdev->dev,
-					    DMA_BIT_MASK(64));
+		pci_using_dac = 1;
 	} else {
-		err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
+		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 		if (err) {
-			err = dma_set_coherent_mask(&pdev->dev,
-						    DMA_BIT_MASK(32));
-			if (err) {
-				dev_err(&pdev->dev, "igc: Wrong DMA config\n");
-				goto err_dma;
-			}
+			dev_err(&pdev->dev,
+				"No usable DMA configuration, aborting\n");
+			goto err_dma;
 		}
 	}
 
-	err = pci_request_selected_regions(pdev,
-					   pci_select_bars(pdev,
-							   IORESOURCE_MEM),
-					   igc_driver_name);
+	err = pci_request_mem_regions(pdev, igc_driver_name);
 	if (err)
 		goto err_pci_reg;