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Message-ID: <e6eda07e-9c58-d438-9b6f-6a3e44ecad11@engleder-embedded.com>
Date: Wed, 7 Dec 2022 21:12:15 +0100
From: Gerhard Engleder <gerhard@...leder-embedded.com>
To: Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
bpf@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, edumazet@...gle.com,
ast@...nel.org, daniel@...earbox.net, hawk@...nel.org,
john.fastabend@...il.com
Subject: Re: [PATCH net-next 6/6] tsnep: Add XDP RX support
On 07.12.22 11:18, Paolo Abeni wrote:
> On Sat, 2022-12-03 at 22:54 +0100, Gerhard Engleder wrote:
>> If BPF program is set up, then run BPF program for every received frame
>> and execute the selected action.
>>
>> Test results with A53 1.2GHz:
>>
>> XDP_DROP (samples/bpf/xdp1)
>> proto 17: 865683 pkt/s
>>
>> XDP_TX (samples/bpf/xdp2)
>> proto 17: 253594 pkt/s
>>
>> XDP_REDIRECT (samples/bpf/xdpsock)
>> sock0@...2:0 rxdrop xdp-drv
>> pps pkts 1.00
>> rx 862,258 4,514,166
>> tx 0 0
>>
>> XDP_REDIRECT (samples/bpf/xdp_redirect)
>> eth2->eth1 608,895 rx/s 0 err,drop/s 608,895 xmit/s
>>
>> Signed-off-by: Gerhard Engleder <gerhard@...leder-embedded.com>
>> ---
>> drivers/net/ethernet/engleder/tsnep_main.c | 100 +++++++++++++++++++++
>> 1 file changed, 100 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
>> index 725b2a1e7be4..4e3c6bd3dc9f 100644
>> --- a/drivers/net/ethernet/engleder/tsnep_main.c
>> +++ b/drivers/net/ethernet/engleder/tsnep_main.c
>> @@ -27,6 +27,7 @@
>> #include <linux/phy.h>
>> #include <linux/iopoll.h>
>> #include <linux/bpf.h>
>> +#include <linux/bpf_trace.h>
>>
>> #define TSNEP_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
>> #define TSNEP_HEADROOM ALIGN(max(TSNEP_SKB_PAD, XDP_PACKET_HEADROOM), 4)
>> @@ -44,6 +45,11 @@
>> #define TSNEP_COALESCE_USECS_MAX ((ECM_INT_DELAY_MASK >> ECM_INT_DELAY_SHIFT) * \
>> ECM_INT_DELAY_BASE_US + ECM_INT_DELAY_BASE_US - 1)
>>
>> +#define TSNEP_XDP_PASS 0
>> +#define TSNEP_XDP_CONSUMED BIT(0)
>> +#define TSNEP_XDP_TX BIT(1)
>> +#define TSNEP_XDP_REDIRECT BIT(2)
>> +
>> enum {
>> __TSNEP_DOWN,
>> };
>> @@ -819,6 +825,11 @@ static inline unsigned int tsnep_rx_offset(struct tsnep_rx *rx)
>> return TSNEP_SKB_PAD;
>> }
>>
>> +static inline unsigned int tsnep_rx_offset_xdp(void)
>
> Please, no 'inline' in c files, the complier will do a better job
> without.
Will be fixed.
>> +{
>> + return XDP_PACKET_HEADROOM;
>> +}
>> +
>> static void tsnep_rx_ring_cleanup(struct tsnep_rx *rx)
>> {
>> struct device *dmadev = rx->adapter->dmadev;
>> @@ -1024,6 +1035,65 @@ static int tsnep_rx_refill(struct tsnep_rx *rx, int count, bool reuse)
>> return i;
>> }
>>
>> +static int tsnep_xdp_run_prog(struct tsnep_rx *rx, struct bpf_prog *prog,
>> + struct xdp_buff *xdp)
>> +{
>> + unsigned int length;
>> + unsigned int sync;
>> + u32 act;
>> +
>> + length = xdp->data_end - xdp->data_hard_start - tsnep_rx_offset_xdp();
>> +
>> + 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 - tsnep_rx_offset_xdp();
>> + sync = max(sync, length);
>> +
>> + switch (act) {
>> + case XDP_PASS:
>> + return TSNEP_XDP_PASS;
>> + case XDP_TX:
>> + if (tsnep_xdp_xmit_back(rx->adapter, xdp) < 0)
>> + goto out_failure;
>> + return TSNEP_XDP_TX;
>> + case XDP_REDIRECT:
>> + if (xdp_do_redirect(rx->adapter->netdev, xdp, prog) < 0)
>> + goto out_failure;
>> + return TSNEP_XDP_REDIRECT;
>> + default:
>> + bpf_warn_invalid_xdp_action(rx->adapter->netdev, prog, act);
>> + fallthrough;
>> + case XDP_ABORTED:
>> +out_failure:
>> + trace_xdp_exception(rx->adapter->netdev, prog, act);
>> + fallthrough;
>> + case XDP_DROP:
>> + page_pool_put_page(rx->page_pool, virt_to_head_page(xdp->data),
>> + sync, true);
>> + return TSNEP_XDP_CONSUMED;
>> + }
>> +}
>> +
>> +static void tsnep_finalize_xdp(struct tsnep_adapter *adapter, int status)
>> +{
>> + int cpu = smp_processor_id();
>> + int queue;
>> + struct netdev_queue *nq;
>> +
>> + if (status & TSNEP_XDP_TX) {
>> + queue = cpu % adapter->num_tx_queues;
>> + nq = netdev_get_tx_queue(adapter->netdev, queue);
>> +
>> + __netif_tx_lock(nq, cpu);
>> + tsnep_xdp_xmit_flush(&adapter->tx[queue]);
>> + __netif_tx_unlock(nq);
>> + }
>> +
>> + if (status & TSNEP_XDP_REDIRECT)
>> + xdp_do_flush();
>> +}
>> +
>> static struct sk_buff *tsnep_build_skb(struct tsnep_rx *rx, struct page *page,
>> int length)
>> {
>> @@ -1062,12 +1132,17 @@ static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
>> int desc_available;
>> int done = 0;
>> enum dma_data_direction dma_dir;
>> + struct bpf_prog *prog;
>> struct tsnep_rx_entry *entry;
>> + struct xdp_buff xdp;
>> + int xdp_status = 0;
>> struct sk_buff *skb;
>> int length;
>> + int retval;
>>
>> desc_available = tsnep_rx_desc_available(rx);
>> dma_dir = page_pool_get_dma_dir(rx->page_pool);
>> + prog = READ_ONCE(rx->adapter->xdp_prog);
>>
>> while (likely(done < budget) && (rx->read != rx->write)) {
>> entry = &rx->entry[rx->read];
>> @@ -1111,6 +1186,28 @@ static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
>> rx->read = (rx->read + 1) % TSNEP_RING_SIZE;
>> desc_available++;
>>
>> + if (prog) {
>> + xdp_init_buff(&xdp, PAGE_SIZE, &rx->xdp_rxq);
>> + xdp_prepare_buff(&xdp, page_address(entry->page),
>> + tsnep_rx_offset_xdp() + TSNEP_RX_INLINE_METADATA_SIZE,
>> + length - TSNEP_RX_INLINE_METADATA_SIZE,
>> + false);
>> + retval = tsnep_xdp_run_prog(rx, prog, &xdp);
>> + } else {
>> + retval = TSNEP_XDP_PASS;
>> + }
>> + if (retval) {
>> + if (retval & (TSNEP_XDP_TX | TSNEP_XDP_REDIRECT))
>> + xdp_status |= retval;
>
> Here you could avoid a couple of conditionals passing xdp_status as an
> additional tsnep_xdp_run_prog() argument, let the latter update it
> under the existing switch, returning a single consumed/pass up bool and
> testing such value just after tsnep_xdp_run_prog().
>
> Mostly a matter of personal tasted I guess.
I will try it.
Thanks for the review!
Gerhard
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