Commit 5db84325 authored by Roger Quadros's avatar Roger Quadros Committed by Jakub Kicinski
Browse files

net: ethernet: ti: am65-cpsw: fix memleak in certain XDP cases 



If the XDP program doesn't result in XDP_PASS then we leak the
memory allocated by am65_cpsw_build_skb().

It is pointless to allocate SKB memory before running the XDP
program as we would be wasting CPU cycles for cases other than XDP_PASS.
Move the SKB allocation after evaluating the XDP program result.

This fixes the memleak. A performance boost is seen for XDP_DROP test.

XDP_DROP test:
Before: 460256 rx/s                  0 err/s
After:  784130 rx/s                  0 err/s

Fixes: 8acacc40 ("net: ethernet: ti: am65-cpsw: Add minimal XDP support")
Signed-off-by: default avatarRoger Quadros <rogerq@kernel.org>
Link: https://patch.msgid.link/20250210-am65-cpsw-xdp-fixes-v1-1-ec6b1f7f1aca@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b698b9a8

drivers/net/ethernet/ti/am65-cpsw-nuss.c

+13 −13
Original line number Diff line number Diff line
@@ -842,7 +842,8 @@ static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma) 


static struct sk_buff *am65_cpsw_build_skb(void *page_addr,

					   struct net_device *ndev,

					   unsigned int len)

					   unsigned int len,

					   unsigned int headroom)

{

	struct sk_buff *skb;
@@ -852,7 +853,7 @@ static struct sk_buff *am65_cpsw_build_skb(void *page_addr, 
	if (unlikely(!skb))

		return NULL;



	skb_reserve(skb, AM65_CPSW_HEADROOM);

	skb_reserve(skb, headroom);

	skb->dev = ndev;



	return skb;
@@ -1315,16 +1316,8 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_rx_flow *flow, 
	dev_dbg(dev, "%s rx csum_info:%#x\n", __func__, csum_info);



	dma_unmap_single(rx_chn->dma_dev, buf_dma, buf_dma_len, DMA_FROM_DEVICE);



	k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);



	skb = am65_cpsw_build_skb(page_addr, ndev,

				  AM65_CPSW_MAX_PACKET_SIZE);

	if (unlikely(!skb)) {

		new_page = page;

		goto requeue;

	}



	if (port->xdp_prog) {

		xdp_init_buff(&xdp, PAGE_SIZE, &port->xdp_rxq[flow->id]);

		xdp_prepare_buff(&xdp, page_addr, AM65_CPSW_HEADROOM,
@@ -1334,9 +1327,16 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_rx_flow *flow, 
		if (*xdp_state != AM65_CPSW_XDP_PASS)

			goto allocate;



		/* Compute additional headroom to be reserved */

		headroom = (xdp.data - xdp.data_hard_start) - skb_headroom(skb);

		skb_reserve(skb, headroom);

		headroom = xdp.data - xdp.data_hard_start;

	} else {

		headroom = AM65_CPSW_HEADROOM;

	}



	skb = am65_cpsw_build_skb(page_addr, ndev,

				  AM65_CPSW_MAX_PACKET_SIZE, headroom);

	if (unlikely(!skb)) {

		new_page = page;

		goto requeue;

	}



	ndev_priv = netdev_priv(ndev);