[PATCH 3.12 080/104] DMA-API: net: intel/ixgbevf: fix 32-bit DMA mask handling

[Jiri Slaby]

From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 53567aa4e00399aa59339bba81b285a5b95f425c upstream.

The fallback to 32-bit DMA mask is rather odd:
	if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)) &&
	    !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));
		if (err) {
			err = dma_set_coherent_mask(&pdev->dev,
						    DMA_BIT_MASK(32));
			if (err) {
				dev_err(&pdev->dev, "No usable DMA "
					"configuration, aborting\n");
				goto err_dma;
			}
		}
		pci_using_dac = 0;
	}
This means we only set the coherent DMA mask in the fallback path if
the DMA mask set failed, which is silly.  This fixes it to set the
coherent DMA mask only if dma_set_mask() succeeded, and to error out
if either fails.

Acked-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 59a62bbfb371..e34c2daac6a0 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -3326,19 +3326,14 @@ static int ixgbevf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (err)
 		return err;
 
-	if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)) &&
-	    !dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64))) {
+	if (!dma_set_mask_and_coherent(&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, "No usable DMA "
-					"configuration, aborting\n");
-				goto err_dma;
-			}
+			dev_err(&pdev->dev, "No usable DMA "
+				"configuration, aborting\n");
+			goto err_dma;
 		}
 		pci_using_dac = 0;
 	}
-- 
2.0.4

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