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Commit ea3349a0 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by David S. Miller
Browse files

mlx4: xdp: Reserve headroom for receiving packet when XDP prog is active 



Reserve XDP_PACKET_HEADROOM for packet and enable bpf_xdp_adjust_head()
support.  This patch only affects the code path when XDP is active.

After testing, the tx_dropped counter is incremented if the xdp_prog sends
more than wire MTU.

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b45f0674

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

+2 −6
Original line number Diff line number Diff line
@@ -51,7 +51,8 @@ 
#include "mlx4_en.h"

#include "en_port.h"



#define MLX4_EN_MAX_XDP_MTU ((int)(PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN)))

#define MLX4_EN_MAX_XDP_MTU ((int)(PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN) - \

				   XDP_PACKET_HEADROOM))



int mlx4_en_setup_tc(struct net_device *dev, u8 up)

{
@@ -2700,11 +2701,6 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog) 
	int err;

	int i;



	if (prog && prog->xdp_adjust_head) {

		en_err(priv, "Does not support bpf_xdp_adjust_head()\n");

		return -EOPNOTSUPP;

	}



	xdp_ring_num = prog ? priv->rx_ring_num : 0;



	/* No need to reconfigure buffers when simply swapping the

drivers/net/ethernet/mellanox/mlx4/en_rx.c

+18 −6
Original line number Diff line number Diff line
@@ -96,7 +96,6 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, 
	struct mlx4_en_rx_alloc page_alloc[MLX4_EN_MAX_RX_FRAGS];

	const struct mlx4_en_frag_info *frag_info;

	struct page *page;

	dma_addr_t dma;

	int i;



	for (i = 0; i < priv->num_frags; i++) {
@@ -115,9 +114,10 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, 


	for (i = 0; i < priv->num_frags; i++) {

		frags[i] = ring_alloc[i];

		dma = ring_alloc[i].dma + ring_alloc[i].page_offset;

		frags[i].page_offset += priv->frag_info[i].rx_headroom;

		rx_desc->data[i].addr = cpu_to_be64(frags[i].dma +

						    frags[i].page_offset);

		ring_alloc[i] = page_alloc[i];

		rx_desc->data[i].addr = cpu_to_be64(dma);

	}



	return 0;
@@ -250,7 +250,8 @@ static int mlx4_en_prepare_rx_desc(struct mlx4_en_priv *priv, 


	if (ring->page_cache.index > 0) {

		frags[0] = ring->page_cache.buf[--ring->page_cache.index];

		rx_desc->data[0].addr = cpu_to_be64(frags[0].dma);

		rx_desc->data[0].addr = cpu_to_be64(frags[0].dma +

						    frags[0].page_offset);

		return 0;

	}
@@ -889,6 +890,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud 
		if (xdp_prog) {

			struct xdp_buff xdp;

			dma_addr_t dma;

			void *orig_data;

			u32 act;



			dma = be64_to_cpu(rx_desc->data[0].addr);
@@ -896,11 +898,19 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud 
						priv->frag_info[0].frag_size,

						DMA_FROM_DEVICE);



			xdp.data = page_address(frags[0].page) +

							frags[0].page_offset;

			xdp.data_hard_start = page_address(frags[0].page);

			xdp.data = xdp.data_hard_start + frags[0].page_offset;

			xdp.data_end = xdp.data + length;

			orig_data = xdp.data;



			act = bpf_prog_run_xdp(xdp_prog, &xdp);



			if (xdp.data != orig_data) {

				length = xdp.data_end - xdp.data;

				frags[0].page_offset = xdp.data -

					xdp.data_hard_start;

			}



			switch (act) {

			case XDP_PASS:

				break;
@@ -1180,6 +1190,7 @@ void mlx4_en_calc_rx_buf(struct net_device *dev) 
		 */

		priv->frag_info[0].frag_stride = PAGE_SIZE;

		priv->frag_info[0].dma_dir = PCI_DMA_BIDIRECTIONAL;

		priv->frag_info[0].rx_headroom = XDP_PACKET_HEADROOM;

		i = 1;

	} else {

		int buf_size = 0;
@@ -1194,6 +1205,7 @@ void mlx4_en_calc_rx_buf(struct net_device *dev) 
				ALIGN(priv->frag_info[i].frag_size,

				      SMP_CACHE_BYTES);

			priv->frag_info[i].dma_dir = PCI_DMA_FROMDEVICE;

			priv->frag_info[i].rx_headroom = 0;

			buf_size += priv->frag_info[i].frag_size;

			i++;

		}

drivers/net/ethernet/mellanox/mlx4/en_tx.c

+5 −4
Original line number Diff line number Diff line
@@ -354,7 +354,7 @@ u32 mlx4_en_recycle_tx_desc(struct mlx4_en_priv *priv, 
	struct mlx4_en_rx_alloc frame = {

		.page = tx_info->page,

		.dma = tx_info->map0_dma,

		.page_offset = 0,

		.page_offset = XDP_PACKET_HEADROOM,

		.page_size = PAGE_SIZE,

	};
@@ -1132,7 +1132,7 @@ netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring, 
	tx_info->page = frame->page;

	frame->page = NULL;

	tx_info->map0_dma = dma;

	tx_info->map0_byte_count = length;

	tx_info->map0_byte_count = PAGE_SIZE;

	tx_info->nr_txbb = nr_txbb;

	tx_info->nr_bytes = max_t(unsigned int, length, ETH_ZLEN);

	tx_info->data_offset = (void *)data - (void *)tx_desc;
@@ -1141,9 +1141,10 @@ netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring, 
	tx_info->linear = 1;

	tx_info->inl = 0;



	dma_sync_single_for_device(priv->ddev, dma, length, PCI_DMA_TODEVICE);

	dma_sync_single_range_for_device(priv->ddev, dma, frame->page_offset,

					 length, PCI_DMA_TODEVICE);



	data->addr = cpu_to_be64(dma);

	data->addr = cpu_to_be64(dma + frame->page_offset);

	data->lkey = ring->mr_key;

	dma_wmb();

	data->byte_count = cpu_to_be32(length);

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

+2 −1
Original line number Diff line number Diff line
@@ -475,7 +475,8 @@ struct mlx4_en_frag_info { 
	u16 frag_prefix_size;

	u32 frag_stride;

	enum dma_data_direction dma_dir;

	int order;

	u16 order;

	u16 rx_headroom;

};



#ifdef CONFIG_MLX4_EN_DCB