Re: [PATCH v3 bpf-next] bpf: devmap: move drop error path to devmap for XDP_REDIRECT
From: Jesper Dangaard Brouer <hidden>
Date: 2021-03-08 14:03:45
Also in:
bpf
On Mon, 8 Mar 2021 12:06:58 +0100 Lorenzo Bianconi [off-list ref] wrote:
We want to change the current ndo_xdp_xmit drop semantics because it will allow us to implement better queue overflow handling. This is working towards the larger goal of a XDP TX queue-hook. Move XDP_REDIRECT error path handling from each XDP ethernet driver to devmap code. According to the new APIs, the driver running the ndo_xdp_xmit pointer, will break tx loop whenever the hw reports a tx error and it will just return to devmap caller the number of successfully transmitted frames. It will be devmap responsability to free dropped frames. Move each XDP ndo_xdp_xmit capable driver to the new APIs: - veth - virtio-net - mvneta - mvpp2 - socionext - amazon ena - bnxt - freescale (dpaa2, dpaa) - xen-frontend - qede - ice - igb - ixgbe - i40e - mlx5 - ti (cpsw, cpsw-new) - tun - sfc Acked-by: Edward Cree <ecree.xilinx@gmail.com> Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> --- More details about the new ndo_xdp_xmit design can be found here [0]. [0] https://github.com/xdp-project/xdp-project/blob/master/areas/core/redesign01_ndo_xdp_xmit.org Changes since v2: - drop wrong comment in ena driver - simplify drop condition using unlikey in the for condition of devmap code - rebase on top of bpf-next - collect acked-by/reviewed-by Changes since v1: - rebase on top of bpf-next - add driver maintainers in cc - add Edward's ack --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 21 ++++++------- drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 20 +++++-------- .../net/ethernet/freescale/dpaa/dpaa_eth.c | 12 ++++---- .../net/ethernet/freescale/dpaa2/dpaa2-eth.c | 2 -- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 15 +++++----- drivers/net/ethernet/intel/ice/ice_txrx.c | 15 +++++----- drivers/net/ethernet/intel/igb/igb_main.c | 11 ++++--- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 11 ++++--- drivers/net/ethernet/marvell/mvneta.c | 13 ++++---- .../net/ethernet/marvell/mvpp2/mvpp2_main.c | 13 ++++---- .../net/ethernet/mellanox/mlx5/core/en/xdp.c | 15 ++++------ drivers/net/ethernet/qlogic/qede/qede_fp.c | 19 +++++------- drivers/net/ethernet/sfc/tx.c | 15 +--------- drivers/net/ethernet/socionext/netsec.c | 16 +++++----- drivers/net/ethernet/ti/cpsw.c | 14 ++++----- drivers/net/ethernet/ti/cpsw_new.c | 14 ++++----- drivers/net/ethernet/ti/cpsw_priv.c | 11 +++---- drivers/net/tun.c | 15 ++++++---- drivers/net/veth.c | 28 +++++++++-------- drivers/net/virtio_net.c | 25 ++++++++-------- drivers/net/xen-netfront.c | 18 +++++------ kernel/bpf/devmap.c | 30 ++++++++----------- 22 files changed, 153 insertions(+), 200 deletions(-)
Acked-by: Jesper Dangaard Brouer <redacted> Acking core changes to bpf/devmap.c (kept below). I've only skimmed the driver changes.
quoted hunk ↗ jump to hunk
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 85d9d1b72a33..d6330bbe1209 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c@@ -330,7 +330,7 @@ bool dev_map_can_have_prog(struct bpf_map *map) static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) { struct net_device *dev = bq->dev; - int sent = 0, drops = 0, err = 0; + int sent = 0, err = 0; int i; if (unlikely(!bq->count))@@ -344,29 +344,23 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q, flags); if (sent < 0) { + /* If ndo_xdp_xmit fails with an errno, no frames have + * been xmit'ed. + */ err = sent; sent = 0; - goto error; } - drops = bq->count - sent; -out: - bq->count = 0; - trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err); - bq->dev_rx = NULL; - __list_del_clearprev(&bq->flush_node); - return; -error: - /* If ndo_xdp_xmit fails with an errno, no frames have been - * xmit'ed and it's our responsibility to them free all. + /* If not all frames have been transmitted, it is our + * responsibility to free them */ - for (i = 0; i < bq->count; i++) { - struct xdp_frame *xdpf = bq->q[i]; + for (i = sent; unlikely(i < bq->count); i++) + xdp_return_frame_rx_napi(bq->q[i]); - xdp_return_frame_rx_napi(xdpf); - drops++; - } - goto out; + trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, bq->count - sent, err); + bq->dev_rx = NULL; + bq->count = 0; + __list_del_clearprev(&bq->flush_node); } /* __dev_flush is called from xdp_do_flush() which _must_ be signaled
-- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer