ixgb: Remove useless DMA-32 fallback configuration

As stated in [1], dma_set_mask() with a 64-bit mask never fails if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

So, if dma_set_mask_and_coherent() succeeds, 'pci_using_dac' is known to be
1.

Simplify code and remove some dead code accordingly.

[1]: https://lkml.org/lkml/2021/6/7/398

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgb/ixgb_main.c b/drivers/net/ethernet/intel/ixgb/ixgb_main.c
index 99d481904ce642a550cf4dec58c1cd88ad2774aa..affdefcca7e307417cb4be1848225adfa887dbb9 100644 (file)
--- a/drivers/net/ethernet/intel/ixgb/ixgb_main.c
+++ b/drivers/net/ethernet/intel/ixgb/ixgb_main.c
@@ -361,7 +361,6 @@ ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        struct net_device *netdev = NULL;
        struct ixgb_adapter *adapter;
        static int cards_found = 0;
-       int pci_using_dac;
        u8 addr[ETH_ALEN];
        int i;
        int err;
@@ -370,16 +369,10 @@ ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        if (err)
                return err;
 
-       pci_using_dac = 0;
        err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
-       if (!err) {
-               pci_using_dac = 1;
-       } else {
-               err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-               if (err) {
-                       pr_err("No usable DMA configuration, aborting\n");
-                       goto err_dma_mask;
-               }
+       if (err) {
+               pr_err("No usable DMA configuration, aborting\n");
+               goto err_dma_mask;
        }
 
        err = pci_request_regions(pdev, ixgb_driver_name);
@@ -444,10 +437,8 @@ ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
                           NETIF_F_HW_VLAN_CTAG_FILTER;
        netdev->hw_features |= NETIF_F_RXCSUM;
 
-       if (pci_using_dac) {
-               netdev->features |= NETIF_F_HIGHDMA;
-               netdev->vlan_features |= NETIF_F_HIGHDMA;
-       }
+       netdev->features |= NETIF_F_HIGHDMA;
+       netdev->vlan_features |= NETIF_F_HIGHDMA;
 
        /* MTU range: 68 - 16114 */
        netdev->min_mtu = ETH_MIN_MTU;