Commit 4e8231f1 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Saeed Mahameed
Browse files

net/mlx5e: Prepare non-linear legacy RQ for XDP multi buffer support 



mlx5e_skb_from_cqe_nonlinear creates an xdp_buff first, putting the
first fragment as the linear part, and the rest of fragments as
fragments to struct skb_shared_info in the tailroom. Then it creates an
SKB in place, based on the xdp_buff. The XDP program is not called in
this commit yet.

This commit contains no functional change, except the SKB is built over
the whole frag_stride of the first fragment, instead of the minimal size
required (headroom, data and skb_shared_info).

Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent e89600eb

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

+61 −14
Original line number Diff line number Diff line
@@ -1567,45 +1567,92 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe, 
			     struct mlx5e_wqe_frag_info *wi, u32 cqe_bcnt)

{

	struct mlx5e_rq_frag_info *frag_info = &rq->wqe.info.arr[0];

	struct mlx5e_wqe_frag_info *head_wi = wi;

	u16 rx_headroom = rq->buff.headroom;

	struct mlx5e_dma_info *di = wi->di;

	struct skb_shared_info *sinfo;

	u32 frag_consumed_bytes;

	u32 first_frag_size;

	struct xdp_buff xdp;

	struct sk_buff *skb;

	u32 truesize;

	void *va;



	va = page_address(di->page) + wi->offset;

	frag_consumed_bytes = min_t(u32, frag_info->frag_size, cqe_bcnt);

	first_frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + frag_consumed_bytes);



	dma_sync_single_range_for_cpu(rq->pdev, di->addr, wi->offset,

				      first_frag_size, DMA_FROM_DEVICE);

				      rq->buff.frame0_sz, DMA_FROM_DEVICE);

	net_prefetch(va + rx_headroom);



	/* XDP is not supported in this configuration, as incoming packets

	 * might spread among multiple pages.

	 */

	skb = mlx5e_build_linear_skb(rq, va, first_frag_size, rx_headroom,

				     frag_consumed_bytes, 0);

	if (unlikely(!skb))

		return NULL;



	page_ref_inc(di->page);

	mlx5e_fill_xdp_buff(rq, va, rx_headroom, frag_consumed_bytes, &xdp);

	sinfo = xdp_get_shared_info_from_buff(&xdp);

	truesize = 0;



	cqe_bcnt -= frag_consumed_bytes;

	frag_info++;

	wi++;



	while (cqe_bcnt) {

		skb_frag_t *frag;



		di = wi->di;



		frag_consumed_bytes = min_t(u32, frag_info->frag_size, cqe_bcnt);



		mlx5e_add_skb_frag(rq, skb, wi->di, wi->offset,

				   frag_consumed_bytes, frag_info->frag_stride);

		dma_sync_single_for_cpu(rq->pdev, di->addr + wi->offset,

					frag_consumed_bytes, DMA_FROM_DEVICE);



		if (!xdp_buff_has_frags(&xdp)) {

			/* Init on the first fragment to avoid cold cache access

			 * when possible.

			 */

			sinfo->nr_frags = 0;

			sinfo->xdp_frags_size = 0;

			xdp_buff_set_frags_flag(&xdp);

		}



		frag = &sinfo->frags[sinfo->nr_frags++];

		__skb_frag_set_page(frag, di->page);

		skb_frag_off_set(frag, wi->offset);

		skb_frag_size_set(frag, frag_consumed_bytes);



		if (page_is_pfmemalloc(di->page))

			xdp_buff_set_frag_pfmemalloc(&xdp);



		sinfo->xdp_frags_size += frag_consumed_bytes;

		truesize += frag_info->frag_stride;



		cqe_bcnt -= frag_consumed_bytes;

		frag_info++;

		wi++;

	}



	di = head_wi->di;



	skb = mlx5e_build_linear_skb(rq, xdp.data_hard_start, rq->buff.frame0_sz,

				     xdp.data - xdp.data_hard_start,

				     xdp.data_end - xdp.data,

				     xdp.data - xdp.data_meta);

	if (unlikely(!skb))

		return NULL;



	page_ref_inc(di->page);



	if (unlikely(xdp_buff_has_frags(&xdp))) {

		int i;



		/* sinfo->nr_frags is reset by build_skb, calculate again. */

		xdp_update_skb_shared_info(skb, wi - head_wi - 1,

					   sinfo->xdp_frags_size, truesize,

					   xdp_buff_is_frag_pfmemalloc(&xdp));



		for (i = 0; i < sinfo->nr_frags; i++) {

			skb_frag_t *frag = &sinfo->frags[i];



			page_ref_inc(skb_frag_page(frag));

		}

	}



	return skb;

}