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net: ethernet: ti: am65-cpsw: fix XDP_DROP, XDP_TX and XDP_REDIRECT
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The following XDP_DROP test from [1] stalls the interface after
250 packets.
~# xdb-bench drop -m native eth0
This is because new RX requests are never queued. Fix that.

The below XDP_TX test from [1] fails with a warning
[  499.947381] XDP_WARN: xdp_update_frame_from_buff(line:277): Driver BUG: missing reserved tailroom
~# xdb-bench tx -m native eth0
Fix that by using PAGE_SIZE during xdp_init_buf().

In XDP_REDIRECT case only 1 packet was processed in rx_poll.
Fix it to process up to budget packets.

Fix all XDP error cases to call trace_xdp_exception() and drop the packet
in am65_cpsw_run_xdp().

[1] xdp-tools suite https://github.com/xdp-project/xdp-tools

Fixes: 8acacc4 ("net: ethernet: ti: am65-cpsw: Add minimal XDP support")
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Julien Panis <jpanis@baylibre.com>
Reviewed-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Roger Quadros authored and Paolo Abeni committed Sep 3, 2024
1 parent 5517ae2 commit 5e24db5
Showing 1 changed file with 34 additions and 28 deletions.
62 changes: 34 additions & 28 deletions drivers/net/ethernet/ti/am65-cpsw-nuss.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -156,12 +156,13 @@
#define AM65_CPSW_CPPI_TX_PKT_TYPE 0x7

/* XDP */
#define AM65_CPSW_XDP_CONSUMED 2
#define AM65_CPSW_XDP_REDIRECT 1
#define AM65_CPSW_XDP_CONSUMED BIT(1)
#define AM65_CPSW_XDP_REDIRECT BIT(0)
#define AM65_CPSW_XDP_PASS 0

/* Include headroom compatible with both skb and xdpf */
#define AM65_CPSW_HEADROOM (max(NET_SKB_PAD, XDP_PACKET_HEADROOM) + NET_IP_ALIGN)
#define AM65_CPSW_HEADROOM_NA (max(NET_SKB_PAD, XDP_PACKET_HEADROOM) + NET_IP_ALIGN)
#define AM65_CPSW_HEADROOM ALIGN(AM65_CPSW_HEADROOM_NA, sizeof(long))

static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
const u8 *dev_addr)
Expand Down Expand Up @@ -933,7 +934,7 @@ static int am65_cpsw_xdp_tx_frame(struct net_device *ndev,
host_desc = k3_cppi_desc_pool_alloc(tx_chn->desc_pool);
if (unlikely(!host_desc)) {
ndev->stats.tx_dropped++;
return -ENOMEM;
return AM65_CPSW_XDP_CONSUMED; /* drop */
}

am65_cpsw_nuss_set_buf_type(tx_chn, host_desc, buf_type);
Expand All @@ -942,7 +943,7 @@ static int am65_cpsw_xdp_tx_frame(struct net_device *ndev,
pkt_len, DMA_TO_DEVICE);
if (unlikely(dma_mapping_error(tx_chn->dma_dev, dma_buf))) {
ndev->stats.tx_dropped++;
ret = -ENOMEM;
ret = AM65_CPSW_XDP_CONSUMED; /* drop */
goto pool_free;
}

Expand Down Expand Up @@ -977,6 +978,7 @@ static int am65_cpsw_xdp_tx_frame(struct net_device *ndev,
/* Inform BQL */
netdev_tx_completed_queue(netif_txq, 1, pkt_len);
ndev->stats.tx_errors++;
ret = AM65_CPSW_XDP_CONSUMED; /* drop */
goto dma_unmap;
}

Expand Down Expand Up @@ -1004,6 +1006,7 @@ static int am65_cpsw_run_xdp(struct am65_cpsw_common *common,
struct bpf_prog *prog;
struct page *page;
u32 act;
int err;

prog = READ_ONCE(port->xdp_prog);
if (!prog)
Expand All @@ -1023,22 +1026,22 @@ static int am65_cpsw_run_xdp(struct am65_cpsw_common *common,

xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf))
break;
goto drop;

__netif_tx_lock(netif_txq, cpu);
ret = am65_cpsw_xdp_tx_frame(ndev, tx_chn, xdpf,
err = am65_cpsw_xdp_tx_frame(ndev, tx_chn, xdpf,
AM65_CPSW_TX_BUF_TYPE_XDP_TX);
__netif_tx_unlock(netif_txq);
if (ret)
break;
if (err)
goto drop;

ndev->stats.rx_bytes += *len;
ndev->stats.rx_packets++;
ret = AM65_CPSW_XDP_CONSUMED;
goto out;
case XDP_REDIRECT:
if (unlikely(xdp_do_redirect(ndev, xdp, prog)))
break;
goto drop;

ndev->stats.rx_bytes += *len;
ndev->stats.rx_packets++;
Expand All @@ -1048,6 +1051,7 @@ static int am65_cpsw_run_xdp(struct am65_cpsw_common *common,
bpf_warn_invalid_xdp_action(ndev, prog, act);
fallthrough;
case XDP_ABORTED:
drop:
trace_xdp_exception(ndev, prog, act);
fallthrough;
case XDP_DROP:
Expand All @@ -1056,7 +1060,6 @@ static int am65_cpsw_run_xdp(struct am65_cpsw_common *common,

page = virt_to_head_page(xdp->data);
am65_cpsw_put_page(rx_chn, page, true, desc_idx);

out:
return ret;
}
Expand Down Expand Up @@ -1095,7 +1098,7 @@ static void am65_cpsw_nuss_rx_csum(struct sk_buff *skb, u32 csum_info)
}

static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
u32 flow_idx, int cpu)
u32 flow_idx, int cpu, int *xdp_state)
{
struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
u32 buf_dma_len, pkt_len, port_id = 0, csum_info;
Expand All @@ -1114,6 +1117,7 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
void **swdata;
u32 *psdata;

*xdp_state = AM65_CPSW_XDP_PASS;
ret = k3_udma_glue_pop_rx_chn(rx_chn->rx_chn, flow_idx, &desc_dma);
if (ret) {
if (ret != -ENODATA)
Expand Down Expand Up @@ -1161,15 +1165,13 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
}

if (port->xdp_prog) {
xdp_init_buff(&xdp, AM65_CPSW_MAX_PACKET_SIZE, &port->xdp_rxq);

xdp_prepare_buff(&xdp, page_addr, skb_headroom(skb),
xdp_init_buff(&xdp, PAGE_SIZE, &port->xdp_rxq);
xdp_prepare_buff(&xdp, page_addr, AM65_CPSW_HEADROOM,
pkt_len, false);

ret = am65_cpsw_run_xdp(common, port, &xdp, desc_idx,
cpu, &pkt_len);
if (ret != AM65_CPSW_XDP_PASS)
return ret;
*xdp_state = am65_cpsw_run_xdp(common, port, &xdp, desc_idx,
cpu, &pkt_len);
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);
Expand All @@ -1193,9 +1195,13 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
stats->rx_bytes += pkt_len;
u64_stats_update_end(&stats->syncp);

allocate:
new_page = page_pool_dev_alloc_pages(rx_chn->page_pool);
if (unlikely(!new_page))
if (unlikely(!new_page)) {
dev_err(dev, "page alloc failed\n");
return -ENOMEM;
}

rx_chn->pages[desc_idx] = new_page;

if (netif_dormant(ndev)) {
Expand Down Expand Up @@ -1229,29 +1235,29 @@ static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
struct am65_cpsw_common *common = am65_cpsw_napi_to_common(napi_rx);
int flow = AM65_CPSW_MAX_RX_FLOWS;
int cpu = smp_processor_id();
bool xdp_redirect = false;
int xdp_state_or = 0;
int cur_budget, ret;
int xdp_state;
int num_rx = 0;

/* process every flow */
while (flow--) {
cur_budget = budget - num_rx;

while (cur_budget--) {
ret = am65_cpsw_nuss_rx_packets(common, flow, cpu);
if (ret) {
if (ret == AM65_CPSW_XDP_REDIRECT)
xdp_redirect = true;
ret = am65_cpsw_nuss_rx_packets(common, flow, cpu,
&xdp_state);
xdp_state_or |= xdp_state;
if (ret)
break;
}
num_rx++;
}

if (num_rx >= budget)
break;
}

if (xdp_redirect)
if (xdp_state_or & AM65_CPSW_XDP_REDIRECT)
xdp_do_flush();

dev_dbg(common->dev, "%s num_rx:%d %d\n", __func__, num_rx, budget);
Expand Down

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