igb: 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>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 38ba92022cd459ea053129ebd9550c32a6e52513..bfa321e4003f3bdfda545ff6b03f19b6af2524b5 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3164,8 +3164,8 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        s32 ret_val;
        static int global_quad_port_a; /* global quad port a indication */
        const struct e1000_info *ei = igb_info_tbl[ent->driver_data];
-       int err, pci_using_dac;
        u8 part_str[E1000_PBANUM_LENGTH];
+       int err;
 
        /* Catch broken hardware that put the wrong VF device ID in
         * the PCIe SR-IOV capability.
@@ -3180,17 +3180,11 @@ static int igb_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) {
-                       dev_err(&pdev->dev,
-                               "No usable DMA configuration, aborting\n");
-                       goto err_dma;
-               }
+       if (err) {
+               dev_err(&pdev->dev,
+                       "No usable DMA configuration, aborting\n");
+               goto err_dma;
        }
 
        err = pci_request_mem_regions(pdev, igb_driver_name);
@@ -3306,8 +3300,7 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        if (hw->mac.type >= e1000_i350)
                netdev->hw_features |= NETIF_F_NTUPLE;
 
-       if (pci_using_dac)
-               netdev->features |= NETIF_F_HIGHDMA;
+       netdev->features |= NETIF_F_HIGHDMA;
 
        netdev->vlan_features |= netdev->features | NETIF_F_TSO_MANGLEID;
        netdev->mpls_features |= NETIF_F_HW_CSUM;