bpf, devmap: Move drop error path to devmap for XDP_REDIRECT

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
responsibility 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

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Camelia Groza <camelia.groza@nxp.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Shay Agroskin <shayagr@amazon.com>
Link: https://lore.kernel.org/bpf/ed670de24f951cfd77590decf0229a0ad7fd12f6.1615201152.git.lorenzo@kernel.org

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 878b31d534ec..cb0d07ff2492 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2934,7 +2934,7 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 	int cpu = smp_processor_id();
 	struct igb_ring *tx_ring;
 	struct netdev_queue *nq;
-	int drops = 0;
+	int nxmit = 0;
 	int i;
 
 	if (unlikely(test_bit(__IGB_DOWN, &adapter->state)))
@@ -2961,10 +2961,9 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 		int err;
 
 		err = igb_xmit_xdp_ring(adapter, tx_ring, xdpf);
-		if (err != IGB_XDP_TX) {
-			xdp_return_frame_rx_napi(xdpf);
-			drops++;
-		}
+		if (err != IGB_XDP_TX)
+			break;
+		nxmit++;
 	}
 
 	__netif_tx_unlock(nq);
@@ -2972,7 +2971,7 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
 	if (unlikely(flags & XDP_XMIT_FLUSH))
 		igb_xdp_ring_update_tail(tx_ring);
 
-	return n - drops;
+	return nxmit;
 }
 
 static const struct net_device_ops igb_netdev_ops = {