[PATCH net-next 2/3] ixgbe: optimize for XDP_REDIRECT in xsk path

[Magnus Karlsson]

From: Magnus Karlsson <magnus.karls...@intel.com>

Optimize ixgbe_run_xdp_zc() for the XDP program verdict being
XDP_REDIRECT in the zsk zero-copy path. This path is only used when
having AF_XDP zero-copy on and in that case most packets will be
directed to user space. This provides a little under 100k extra
packets in throughput on my server when running l2fwd in xdpsock.

Signed-off-by: Magnus Karlsson <magnus.karls...@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
index 3771857cf887..91ad5b902673 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
@@ -104,6 +104,13 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
        xdp_prog = READ_ONCE(rx_ring->xdp_prog);
        act = bpf_prog_run_xdp(xdp_prog, xdp);
 
+       if (likely(act == XDP_REDIRECT)) {
+               err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
+               result = !err ? IXGBE_XDP_REDIR : IXGBE_XDP_CONSUMED;
+               rcu_read_unlock();
+               return result;
+       }
+
        switch (act) {
        case XDP_PASS:
                break;
@@ -115,10 +122,6 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter,
                }
                result = ixgbe_xmit_xdp_ring(adapter, xdpf);
                break;
-       case XDP_REDIRECT:
-               err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog);
-               result = !err ? IXGBE_XDP_REDIR : IXGBE_XDP_CONSUMED;
-               break;
        default:
                bpf_warn_invalid_xdp_action(act);
                fallthrough;
-- 
2.29.0