igc: Add support for XDP_TX action

Add support for XDP_TX action which enables XDP programs to transmit
back receiving frames.

I225 controller has only 4 Tx hardware queues. Since XDP programs may
not even issue an XDP_TX action, this patch doesn't reserve dedicated
queues just for XDP like other Intel drivers do. Instead, the queues
are shared between the network stack and XDP. The netdev queue lock is
used to ensure mutual exclusion.

Since frames can now be transmitted via XDP_TX, the igc_tx_buffer
structure is modified so we are able to save a reference to the xdp
frame for later clean up once the packet is transmitted. The tx_buffer
is mapped to either a skb or a xdpf so we use a union to save the skb
or xdpf pointer and have a bit in tx_flags to indicate which field to
use.

This patch has been tested with the sample app "xdp2" located in
samples/bpf/ dir.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_xdp.c b/drivers/net/ethernet/intel/igc/igc_xdp.c
index 27c886a254f1..11133c4619bb 100644
--- a/drivers/net/ethernet/intel/igc/igc_xdp.c
+++ b/drivers/net/ethernet/intel/igc/igc_xdp.c
@@ -31,3 +31,30 @@ int igc_xdp_set_prog(struct igc_adapter *adapter, struct bpf_prog *prog,
 
 	return 0;
 }
+
+int igc_xdp_register_rxq_info(struct igc_ring *ring)
+{
+	struct net_device *dev = ring->netdev;
+	int err;
+
+	err = xdp_rxq_info_reg(&ring->xdp_rxq, dev, ring->queue_index, 0);
+	if (err) {
+		netdev_err(dev, "Failed to register xdp rxq info\n");
+		return err;
+	}
+
+	err = xdp_rxq_info_reg_mem_model(&ring->xdp_rxq, MEM_TYPE_PAGE_SHARED,
+					 NULL);
+	if (err) {
+		netdev_err(dev, "Failed to register xdp rxq mem model\n");
+		xdp_rxq_info_unreg(&ring->xdp_rxq);
+		return err;
+	}
+
+	return 0;
+}
+
+void igc_xdp_unregister_rxq_info(struct igc_ring *ring)
+{
+	xdp_rxq_info_unreg(&ring->xdp_rxq);
+}