Commit 84a0a231 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Daniel Borkmann
Browse files

net/mlx5e: XDP_TX from UMEM support 



When an XDP program returns XDP_TX, and the RQ is XSK-enabled, it
requires careful handling, because convert_to_xdp_frame creates a new
page and copies the data there, while our driver expects the xdp_frame
to point to the same memory as the xdp_buff. Handle this case
separately: map the page, and in the end unmap it and call
xdp_return_frame.

Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
Acked-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent b9673cf5

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c

+42 −8
Original line number Diff line number Diff line
@@ -69,14 +69,48 @@ mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_rq *rq, 
	xdptxd.data = xdpf->data;

	xdptxd.len  = xdpf->len;



	if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY) {

		/* The xdp_buff was in the UMEM and was copied into a newly

		 * allocated page. The UMEM page was returned via the ZCA, and

		 * this new page has to be mapped at this point and has to be

		 * unmapped and returned via xdp_return_frame on completion.

		 */



		/* Prevent double recycling of the UMEM page. Even in case this

		 * function returns false, the xdp_buff shouldn't be recycled,

		 * as it was already done in xdp_convert_zc_to_xdp_frame.

		 */

		__set_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags); /* non-atomic */



		xdpi.mode = MLX5E_XDP_XMIT_MODE_FRAME;



		dma_addr = dma_map_single(sq->pdev, xdptxd.data, xdptxd.len,

					  DMA_TO_DEVICE);

		if (dma_mapping_error(sq->pdev, dma_addr)) {

			xdp_return_frame(xdpf);

			return false;

		}



		xdptxd.dma_addr     = dma_addr;

		xdpi.frame.xdpf     = xdpf;

		xdpi.frame.dma_addr = dma_addr;

	} else {

		/* Driver assumes that convert_to_xdp_frame returns an xdp_frame

		 * that points to the same memory region as the original

		 * xdp_buff. It allows to map the memory only once and to use

		 * the DMA_BIDIRECTIONAL mode.

		 */



		xdpi.mode = MLX5E_XDP_XMIT_MODE_PAGE;



		dma_addr = di->addr + (xdpf->data - (void *)xdpf);

	dma_sync_single_for_device(sq->pdev, dma_addr, xdptxd.len, DMA_TO_DEVICE);

		dma_sync_single_for_device(sq->pdev, dma_addr, xdptxd.len,

					   DMA_TO_DEVICE);



		xdptxd.dma_addr = dma_addr;

		xdpi.page.rq    = rq;

		xdpi.page.di    = *di;

	}



	return sq->xmit_xdp_frame(sq, &xdptxd, &xdpi);

}
@@ -298,13 +332,13 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq, 


		switch (xdpi.mode) {

		case MLX5E_XDP_XMIT_MODE_FRAME:

			/* XDP_REDIRECT */

			/* XDP_TX from the XSK RQ and XDP_REDIRECT */

			dma_unmap_single(sq->pdev, xdpi.frame.dma_addr,

					 xdpi.frame.xdpf->len, DMA_TO_DEVICE);

			xdp_return_frame(xdpi.frame.xdpf);

			break;

		case MLX5E_XDP_XMIT_MODE_PAGE:

			/* XDP_TX */

			/* XDP_TX from the regular RQ */

			mlx5e_page_release(xdpi.page.rq, &xdpi.page.di, recycle);

			break;

		default:

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