[PATCH 3.12 076/104] DMA-API: net: intel/ixgbe: 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 f5f2eda8049644a27af5fdf59c3766589358e435 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/ixgbe/ixgbe_main.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 0ade0cd5ef53..bf046e14ceb5 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7490,19 +7490,14 @@ static int ixgbe_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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