[PATCH net-next V2 2/5] net/mlx5e: XDP, Improve dma address calculation of linear part for XDP_TX

Tariq Toukan
2026-04-03T09:10:41Z

From: Dragos Tatulea <dtatulea@nvidia.com>

When calculating the dma address of the linear part of an XDP frame, the
formula assumes that there is a single XDP buffer per page. Extend the
formula to allow multiple XDP buffers per page by calculating the data
offset in the page.

This is a preparation for the upcoming removal of a single XDP buffer
per page limitation when the formula will no longer be correct.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index 04e1b5fa4825..d3bab198c99c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -123,7 +123,7 @@ mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_rq *rq,
* mode.
*/

- dma_addr = page_pool_get_dma_addr(page) + (xdpf->data - (void *)xdpf);
+ dma_addr = page_pool_get_dma_addr(page) + offset_in_page(xdpf->data);
dma_sync_single_for_device(sq->pdev, dma_addr, xdptxd->len, DMA_BIDIRECTIONAL);

if (xdptxd->has_frags) {
--
2.44.0