Thread (21 messages) 21 messages, 6 authors, 22d ago

Re: [PATCH net-next 09/14] net/mlx5: Remove obsolete 32-bit DMA mask fallback

From: Tariq Toukan <tariqt@nvidia.com>
Date: 2026-09-07 08:40:54
Also in: linux-rdma, lkml


On 03/09/2026 11:43, Ruizhe Zhou wrote:
quoted hunk ↗ jump to hunk
The DMA API guarantees support for masks of 32 bits or wider and
explicitly identifies retrying a 32-bit mask after a 64-bit request as
incorrect:
https://docs.kernel.org/core-api/dma-api-howto.html#dma-addressing-capabilities

Remove the obsolete fallback while retaining the error check so that a
genuine DMA setup failure is still reported and aborts initialization.

Signed-off-by: Ruizhe Zhou <redacted>
---
  drivers/net/ethernet/mellanox/mlx5/core/main.c | 8 ++------
  1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 5f28d906c35b..3a3b0ec4aad1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -184,12 +184,8 @@ static int set_dma_caps(struct pci_dev *pdev)
  
  	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
  	if (err) {
-		dev_warn(&pdev->dev, "Warning: couldn't set 64-bit PCI DMA mask\n");
-		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-		if (err) {
-			dev_err(&pdev->dev, "Can't set PCI DMA mask, aborting\n");
-			return err;
-		}
+		dev_err(&pdev->dev, "Can't set PCI DMA mask, aborting\n");
+		return err;
  	}
  
  	dma_set_max_seg_size(&pdev->dev, 2u * 1024 * 1024 * 1024);
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
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