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Mon, 28 Oct 2019 16:33:27 +0000 (UTC) Received: from carbon (ovpn-200-19.brq.redhat.com [10.40.200.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 37C5B5C1B2; Mon, 28 Oct 2019 16:33:22 +0000 (UTC) Date: Mon, 28 Oct 2019 17:33:21 +0100 From: Jesper Dangaard Brouer To: Charles McLachlan Cc: , , , brouer@redhat.com Subject: Re: [PATCH net-next v2 2/6] sfc: perform XDP processing on received packets Message-ID: <20191028173321.5254abf3@carbon> In-Reply-To: <38a43fa5-5682-ffd9-f33e-5b7e04d50903@solarflare.com> References: <74c15338-c13e-5b7b-9cc5-844cd9262be3@solarflare.com> <38a43fa5-5682-ffd9-f33e-5b7e04d50903@solarflare.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: rbmpyIfQNmSKWCwZ215gEw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 28 Oct 2019 13:59:21 +0000 Charles McLachlan wrote: > diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.= c > index 85ec07f5a674..6fabb1925ff1 100644 > --- a/drivers/net/ethernet/sfc/rx.c > +++ b/drivers/net/ethernet/sfc/rx.c [...] > @@ -635,6 +642,103 @@ static void efx_rx_deliver(struct efx_channel *chan= nel, u8 *eh, > =09=09netif_receive_skb(skb); > } > =20 > +/** efx_do_xdp: perform XDP processing on a received packet > + * > + * Returns true if packet should still be delivered. > + */ > +static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel, > +=09=09 struct efx_rx_buffer *rx_buf, u8 **ehp) > +{ > +=09u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE]; > +=09struct efx_rx_queue *rx_queue; > +=09struct bpf_prog *xdp_prog; > +=09struct xdp_buff xdp; > +=09u32 xdp_act; > +=09s16 offset; > +=09int err; > + > +=09rcu_read_lock(); > +=09xdp_prog =3D rcu_dereference(efx->xdp_prog); > +=09if (!xdp_prog) { > +=09=09rcu_read_unlock(); > +=09=09return true; > +=09} > + > +=09rx_queue =3D efx_channel_get_rx_queue(channel); > + > +=09if (unlikely(channel->rx_pkt_n_frags > 1)) { > +=09=09/* We can't do XDP on fragmented packets - drop. */ > +=09=09rcu_read_unlock(); > +=09=09efx_free_rx_buffers(rx_queue, rx_buf, > +=09=09=09=09 channel->rx_pkt_n_frags); > +=09=09if (net_ratelimit()) > +=09=09=09netif_err(efx, rx_err, efx->net_dev, > +=09=09=09=09 "XDP is not possible with multiple receive fragments (%d)\= n", > +=09=09=09=09 channel->rx_pkt_n_frags); > +=09=09return false; > +=09} > + > +=09dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr, > +=09=09=09=09rx_buf->len, DMA_FROM_DEVICE); > + > +=09/* Save the rx prefix. */ > +=09EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE); > +=09memcpy(rx_prefix, *ehp - efx->rx_prefix_size, > +=09 efx->rx_prefix_size); > + > +=09xdp.data =3D *ehp; > +=09xdp.data_hard_start =3D xdp.data - XDP_PACKET_HEADROOM; > + > +=09/* No support yet for XDP metadata */ > +=09xdp_set_data_meta_invalid(&xdp); > +=09xdp.data_end =3D xdp.data + rx_buf->len; > +=09xdp.rxq =3D &rx_queue->xdp_rxq_info; You can optimize this and only assign xdp_rxq_info once per NAPI. E.g. if you "allocate" struct xdp_buff on the callers stack, and pass it in as a pointer. > + > +=09xdp_act =3D bpf_prog_run_xdp(xdp_prog, &xdp); > +=09rcu_read_unlock(); > + > +=09offset =3D (u8 *)xdp.data - *ehp; > + > +=09switch (xdp_act) { > +=09case XDP_PASS: > +=09=09/* Fix up rx prefix. */ > +=09=09if (offset) { > +=09=09=09*ehp +=3D offset; > +=09=09=09rx_buf->page_offset +=3D offset; > +=09=09=09rx_buf->len -=3D offset; > +=09=09=09memcpy(*ehp - efx->rx_prefix_size, rx_prefix, > +=09=09=09 efx->rx_prefix_size); > +=09=09} > +=09=09break; > + > +=09case XDP_TX: > +=09=09return -EOPNOTSUPP; > + > +=09case XDP_REDIRECT: > +=09=09err =3D xdp_do_redirect(efx->net_dev, &xdp, xdp_prog); > +=09=09if (unlikely(err)) { > +=09=09=09efx_free_rx_buffers(rx_queue, rx_buf, 1); > +=09=09=09if (net_ratelimit()) > +=09=09=09=09netif_err(efx, rx_err, efx->net_dev, > +=09=09=09=09=09 "XDP redirect failed (%d)\n", err); > +=09=09} > +=09=09break; > + > +=09default: > +=09=09bpf_warn_invalid_xdp_action(xdp_act); > +=09=09/* Fall through */ > +=09case XDP_ABORTED: You are missing a tracepoint to catch ABORTED, e.g: trace_xdp_exception(netdev, xdp_prog, xdp_act); > +=09=09efx_free_rx_buffers(rx_queue, rx_buf, 1); > +=09=09break; You can do a /* Fall through */ to case XDP_DROP. > +=09case XDP_DROP: > +=09=09efx_free_rx_buffers(rx_queue, rx_buf, 1); > +=09=09break; > +=09} > + > +=09return xdp_act =3D=3D XDP_PASS; > +} You can verify/test tracepoint for ABORTED as described here: https://github.com/xdp-project/xdp-tutorial/tree/master/basic02-prog-by-na= me#assignment-2-add-xdp_abort-program Thanks for working on this! --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer