2022-01-09 18:43:50

by Christophe JAILLET

Subject: [PATCH] igbvf: 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 <[email protected]>
---
This patch was not part of the 1st serie I've sent. So there is no
Reviewed-by tag.
---
drivers/net/ethernet/intel/igbvf/netdev.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c
index b78407289741..43ced78c3a2e 100644
--- a/drivers/net/ethernet/intel/igbvf/netdev.c
+++ b/drivers/net/ethernet/intel/igbvf/netdev.c
@@ -2684,25 +2684,18 @@ static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
struct igbvf_adapter *adapter;
struct e1000_hw *hw;
const struct igbvf_info *ei = igbvf_info_tbl[ent->driver_data];
-
static int cards_found;
- int err, pci_using_dac;
+ int err;

err = pci_enable_device_mem(pdev);
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_regions(pdev, igbvf_driver_name);
@@ -2783,10 +2776,7 @@ static int igbvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
netdev->hw_features |= NETIF_F_GSO_PARTIAL |
IGBVF_GSO_PARTIAL_FEATURES;

- netdev->features = netdev->hw_features;
-
- if (pci_using_dac)
- netdev->features |= NETIF_F_HIGHDMA;
+ netdev->features = netdev->hw_features | NETIF_F_HIGHDMA;

netdev->vlan_features |= netdev->features | NETIF_F_TSO_MANGLEID;
netdev->mpls_features |= NETIF_F_HW_CSUM;
--
2.32.0

2022-01-21 19:15:22

by Jankowski, Konrad0

Subject: RE: [Intel-wired-lan] [PATCH] igbvf: Remove useless DMA-32 fallback configuration

> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf Of
> Christophe JAILLET
> Sent: niedziela, 9 stycznia 2022 19:44
> To: Brandeburg, Jesse <[email protected]>; Nguyen, Anthony L
> <[email protected]>; David S. Miller <[email protected]>;
> Jakub Kicinski <[email protected]>
> Cc: Christophe JAILLET <[email protected]>; intel-wired-
> [email protected]; [email protected]; linux-
> [email protected]; [email protected]
> Subject: [Intel-wired-lan] [PATCH] igbvf: 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 <[email protected]>
> ---
> This patch was not part of the 1st serie I've sent. So there is no Reviewed-by
> tag.
> ---
> drivers/net/ethernet/intel/igbvf/netdev.c | 22 ++++++----------------
> 1 file changed, 6 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c
> b/drivers/net/ethernet/intel/igbvf/netdev.c
> index b78407289741..43ced78c3a2e 100644
> --- a/drivers/net/ethernet/intel/igbvf/netdev.c
> +++ b/drivers/net/ethernet/intel/igbvf/netdev.c

Tested-by: Konrad Jankowski <[email protected]>