Commit 495de55f authored by Ilias Apalodimas's avatar Ilias Apalodimas Committed by Alexei Starovoitov
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net: netsec: Add support for XDP frame size 



This driver takes advantage of page_pool PP_FLAG_DMA_SYNC_DEV that
can help reduce the number of cache-lines that need to be flushed
when doing DMA sync for_device. Due to xdp_adjust_tail can grow the
area accessible to the by the CPU (can possibly write into), then max
sync length *after* bpf_prog_run_xdp() needs to be taken into account.

For XDP_TX action the driver is smart and does DMA-sync. When growing
tail this is still safe, because page_pool have DMA-mapped the entire
page size.

Signed-off-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/bpf/158945336295.97035.15034759661036971024.stgit@firesoul
parent 494f44d5

drivers/net/ethernet/socionext/netsec.c

+18 −12
Original line number Diff line number Diff line
@@ -884,23 +884,28 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog, 
			  struct xdp_buff *xdp)

{

	struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];

	unsigned int len = xdp->data_end - xdp->data;

	unsigned int sync, len = xdp->data_end - xdp->data;

	u32 ret = NETSEC_XDP_PASS;

	struct page *page;

	int err;

	u32 act;



	act = bpf_prog_run_xdp(prog, xdp);



	/* Due xdp_adjust_tail: DMA sync for_device cover max len CPU touch */

	sync = xdp->data_end - xdp->data_hard_start - NETSEC_RXBUF_HEADROOM;

	sync = max(sync, len);



	switch (act) {

	case XDP_PASS:

		ret = NETSEC_XDP_PASS;

		break;

	case XDP_TX:

		ret = netsec_xdp_xmit_back(priv, xdp);

		if (ret != NETSEC_XDP_TX)

			page_pool_put_page(dring->page_pool,

					   virt_to_head_page(xdp->data), len,

					   true);

		if (ret != NETSEC_XDP_TX) {

			page = virt_to_head_page(xdp->data);

			page_pool_put_page(dring->page_pool, page, sync, true);

		}

		break;

	case XDP_REDIRECT:

		err = xdp_do_redirect(priv->ndev, xdp, prog);
@@ -908,9 +913,8 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog, 
			ret = NETSEC_XDP_REDIR;

		} else {

			ret = NETSEC_XDP_CONSUMED;

			page_pool_put_page(dring->page_pool,

					   virt_to_head_page(xdp->data), len,

					   true);

			page = virt_to_head_page(xdp->data);

			page_pool_put_page(dring->page_pool, page, sync, true);

		}

		break;

	default:
@@ -921,8 +925,8 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog, 
		/* fall through -- handle aborts by dropping packet */

	case XDP_DROP:

		ret = NETSEC_XDP_CONSUMED;

		page_pool_put_page(dring->page_pool,

				   virt_to_head_page(xdp->data), len, true);

		page = virt_to_head_page(xdp->data);

		page_pool_put_page(dring->page_pool, page, sync, true);

		break;

	}
@@ -936,10 +940,14 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget) 
	struct netsec_rx_pkt_info rx_info;

	enum dma_data_direction dma_dir;

	struct bpf_prog *xdp_prog;

	struct xdp_buff xdp;

	u16 xdp_xmit = 0;

	u32 xdp_act = 0;

	int done = 0;



	xdp.rxq = &dring->xdp_rxq;

	xdp.frame_sz = PAGE_SIZE;



	rcu_read_lock();

	xdp_prog = READ_ONCE(priv->xdp_prog);

	dma_dir = page_pool_get_dma_dir(dring->page_pool);
@@ -953,7 +961,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget) 
		struct sk_buff *skb = NULL;

		u16 pkt_len, desc_len;

		dma_addr_t dma_handle;

		struct xdp_buff xdp;

		void *buf_addr;



		if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD)) {
@@ -1002,7 +1009,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget) 
		xdp.data = desc->addr + NETSEC_RXBUF_HEADROOM;

		xdp_set_data_meta_invalid(&xdp);

		xdp.data_end = xdp.data + pkt_len;

		xdp.rxq = &dring->xdp_rxq;



		if (xdp_prog) {

			xdp_result = netsec_run_xdp(priv, xdp_prog, &xdp);

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