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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: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Maxim Mikityanskiy 2019-06-26 17:35:34 +03:00 committed by Daniel Borkmann
parent b9673cf555
commit 84a0a2310d
1 changed files with 42 additions and 8 deletions
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40
drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
View File

@ -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: