target/linux/generic/backport-5.15/730-08-v6.3-net-dsa-add-support-for-DSA-rx-offloading-via-metada.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Tue, 8 Nov 2022 15:03:15 +0100
   3 Subject: [PATCH] net: dsa: add support for DSA rx offloading via
   4  metadata dst
   5
   6 If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
   7 port netdev, assume that it carries the port number and that there is no DSA
   8 tag present in the skb data.
   9
  10 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  11 ---
  12
  13 --- a/net/core/flow_dissector.c
  14 +++ b/net/core/flow_dissector.c
  15 @@ -940,12 +940,14 @@ bool __skb_flow_dissect(const struct net
  16  #if IS_ENABLED(CONFIG_NET_DSA)
  17                 if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) &&
  18                              proto == htons(ETH_P_XDSA))) {
  19 +                       struct metadata_dst *md_dst = skb_metadata_dst(skb);
  20                         const struct dsa_device_ops *ops;
  21                         int offset = 0;
  22
  23                         ops = skb->dev->dsa_ptr->tag_ops;
  24                         /* Only DSA header taggers break flow dissection */
  25 -                       if (ops->needed_headroom) {
  26 +                       if (ops->needed_headroom &&
  27 +                           (!md_dst || md_dst->type != METADATA_HW_PORT_MUX)) {
  28                                 if (ops->flow_dissect)
  29                                         ops->flow_dissect(skb, &proto, &offset);
  30                                 else
  31 --- a/net/dsa/dsa.c
  32 +++ b/net/dsa/dsa.c
  33 @@ -20,6 +20,7 @@
  34  #include <linux/phy_fixed.h>
  35  #include <linux/ptp_classify.h>
  36  #include <linux/etherdevice.h>
  37 +#include <net/dst_metadata.h>
  38
  39  #include "dsa_priv.h"
  40
  41 @@ -225,6 +226,7 @@ static bool dsa_skb_defer_rx_timestamp(s
  42  static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
  43                           struct packet_type *pt, struct net_device *unused)
  44  {
  45 +       struct metadata_dst *md_dst = skb_metadata_dst(skb);
  46         struct dsa_port *cpu_dp = dev->dsa_ptr;
  47         struct sk_buff *nskb = NULL;
  48         struct dsa_slave_priv *p;
  49 @@ -238,7 +240,22 @@ static int dsa_switch_rcv(struct sk_buff
  50         if (!skb)
  51                 return 0;
  52
  53 -       nskb = cpu_dp->rcv(skb, dev);
  54 +       if (md_dst && md_dst->type == METADATA_HW_PORT_MUX) {
  55 +               unsigned int port = md_dst->u.port_info.port_id;
  56 +
  57 +               skb_dst_drop(skb);
  58 +               if (!skb_has_extensions(skb))
  59 +                       skb->slow_gro = 0;
  60 +
  61 +               skb->dev = dsa_master_find_slave(dev, 0, port);
  62 +               if (likely(skb->dev)) {
  63 +                       dsa_default_offload_fwd_mark(skb);
  64 +                       nskb = skb;
  65 +               }
  66 +       } else {
  67 +               nskb = cpu_dp->rcv(skb, dev);
  68 +       }
  69 +
  70         if (!nskb) {
  71                 kfree_skb(skb);
  72                 return 0;