[PATCH] vmxnet3: Remove useless DMA-32 fallback configuration

[PATCH] vmxnet3: Remove useless DMA-32 fallback configuration

[Christophe JAILLET]

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, 'dma64' is know to be 'true'.

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>
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index fd407c0e2856..d9d90baac72a 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -3159,14 +3159,14 @@ vmxnet3_change_mtu(struct net_device *netdev, int new_mtu)
 
 
 static void
-vmxnet3_declare_features(struct vmxnet3_adapter *adapter, bool dma64)
+vmxnet3_declare_features(struct vmxnet3_adapter *adapter)
 {
 	struct net_device *netdev = adapter->netdev;
 
 	netdev->hw_features = NETIF_F_SG | NETIF_F_RXCSUM |
 		NETIF_F_HW_CSUM | NETIF_F_HW_VLAN_CTAG_TX |
 		NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_TSO | NETIF_F_TSO6 |
-		NETIF_F_LRO;
+		NETIF_F_LRO | NETIF_F_HIGHDMA;
 
 	if (VMXNET3_VERSION_GE_4(adapter)) {
 		netdev->hw_features |= NETIF_F_GSO_UDP_TUNNEL |
@@ -3179,8 +3179,6 @@ vmxnet3_declare_features(struct vmxnet3_adapter *adapter, bool dma64)
 			NETIF_F_GSO_UDP_TUNNEL_CSUM;
 	}
 
-	if (dma64)
-		netdev->hw_features |= NETIF_F_HIGHDMA;
 	netdev->vlan_features = netdev->hw_features &
 				~(NETIF_F_HW_VLAN_CTAG_TX |
 				  NETIF_F_HW_VLAN_CTAG_RX);
@@ -3397,7 +3395,6 @@ vmxnet3_probe_device(struct pci_dev *pdev,
 #endif
 	};
 	int err;
-	bool dma64;
 	u32 ver;
 	struct net_device *netdev;
 	struct vmxnet3_adapter *adapter;
@@ -3439,15 +3436,10 @@ vmxnet3_probe_device(struct pci_dev *pdev,
 	adapter->rx_ring_size = VMXNET3_DEF_RX_RING_SIZE;
 	adapter->rx_ring2_size = VMXNET3_DEF_RX_RING2_SIZE;
 
-	if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)) == 0) {
-		dma64 = true;
-	} else {
-		err = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
-		if (err) {
-			dev_err(&pdev->dev, "dma_set_mask failed\n");
-			goto err_set_mask;
-		}
-		dma64 = false;
+	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	if (err) {
+		dev_err(&pdev->dev, "dma_set_mask failed\n");
+		goto err_set_mask;
 	}
 
 	spin_lock_init(&adapter->cmd_lock);
@@ -3614,7 +3606,7 @@ vmxnet3_probe_device(struct pci_dev *pdev,
 	}
 
 	SET_NETDEV_DEV(netdev, &pdev->dev);
-	vmxnet3_declare_features(adapter, dma64);
+	vmxnet3_declare_features(adapter);
 
 	adapter->rxdata_desc_size = VMXNET3_VERSION_GE_3(adapter) ?
 		VMXNET3_DEF_RXDATA_DESC_SIZE : 0;
-- 
2.32.0

Re: [PATCH] vmxnet3: Remove useless DMA-32 fallback configuration

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Sun,  9 Jan 2022 09:50:22 +0100 you wrote:
> 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, 'dma64' is know to be 'true'.
> 
> Simplify code and remove some dead code accordingly.
> 
> [...]

Here is the summary with links:
  - vmxnet3: Remove useless DMA-32 fallback configuration
    https://git.kernel.org/netdev/net-next/c/c38f30683956

You are awesome, thank you!
-- 
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