[PATCH] i40e: Remove useless DMA-32 fallback configuration

From: Christophe JAILLET
Date: Sun Jan 09 2022 - 12:16:00 EST


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@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 635a95927e93..4f6ee5c44f75 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -7385,9 +7385,9 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
resource_size_t flash_start, flash_len;
static int cards_found;
u16 aspm_disable_flag = 0;
- int bars, i, err, pci_using_dac;
u16 eeprom_data = 0;
u16 eeprom_apme_mask = E1000_EEPROM_APME;
+ int bars, i, err;
s32 ret_val = 0;

if (ei->flags2 & FLAG2_DISABLE_ASPM_L0S)
@@ -7401,17 +7401,11 @@ static int e1000_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;
}

bars = pci_select_bars(pdev, IORESOURCE_MEM);
@@ -7547,10 +7541,8 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

netdev->priv_flags |= IFF_UNICAST_FLT;

- 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 - max_hw_frame_size */
netdev->min_mtu = ETH_MIN_MTU;
--
2.32.0