[PATCH net-next v1 08/11] eth: fbnic: Support XDP redirect

["Björn Töpel" <bjorn@kernel.org>]

fbnic treats XDP_REDIRECT as an invalid action and drops the packet,
so AF_XDP, devmap and cpumap do not work. A failed redirect counts as
received, as XDP_DROP does, and as dropped.

Signed-off-by: Björn Töpel <bjorn@kernel.org>
---
 .../net/ethernet/meta/fbnic/fbnic_netdev.c    |  4 +++-
 drivers/net/ethernet/meta/fbnic/fbnic_txrx.c  | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
index 8a6703afca38..ae2585508690 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
@@ -822,7 +822,9 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
 	netdev->hw_enc_features |= netdev->features;
 	netdev->features |= NETIF_F_NTUPLE;
 
-	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_RX_SG;
+	netdev->xdp_features = NETDEV_XDP_ACT_BASIC |
+			       NETDEV_XDP_ACT_REDIRECT |
+			       NETDEV_XDP_ACT_RX_SG;
 
 	netdev->min_mtu = IPV6_MIN_MTU;
 	netdev->max_mtu = FBNIC_MAX_JUMBO_FRAME_SIZE - ETH_HLEN;
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
index 0bcee152d47c..51d573c9c5b8 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
@@ -22,6 +22,8 @@ enum {
 	FBNIC_XDP_PASS = 0,
 	FBNIC_XDP_CONSUME,
 	FBNIC_XDP_TX,
+	FBNIC_XDP_REDIRECT,
+	FBNIC_XDP_REDIRECT_ERR,
 	FBNIC_XDP_LEN_ERR,
 };
 
@@ -1211,6 +1213,10 @@ static struct sk_buff *fbnic_run_xdp(struct fbnic_napi_vector *nv,
 		return fbnic_build_skb(nv, pkt);
 	case XDP_TX:
 		return ERR_PTR(fbnic_pkt_tx(nv, pkt));
+	case XDP_REDIRECT:
+		if (xdp_do_redirect(nv->napi.dev, &pkt->buff, xdp_prog))
+			return ERR_PTR(-FBNIC_XDP_REDIRECT_ERR);
+		return ERR_PTR(-FBNIC_XDP_REDIRECT);
 	default:
 		bpf_warn_invalid_xdp_action(nv->napi.dev, xdp_prog, act);
 		fallthrough;
@@ -1280,6 +1286,7 @@ static int fbnic_clean_rcq(struct fbnic_napi_vector *nv,
 	struct fbnic_ring *rcq = &qt->cmpl;
 	struct fbnic_pkt_buff *pkt;
 	__le64 *raw_rcd, done;
+	bool redirect = false;
 	u32 head = rcq->head;
 
 	done = (head & (rcq->size_mask + 1)) ? cpu_to_le64(FBNIC_RCD_DONE) : 0;
@@ -1336,6 +1343,16 @@ static int fbnic_clean_rcq(struct fbnic_napi_vector *nv,
 				pkt_tail = nv->qt[0].sub1.tail;
 			} else if (PTR_ERR(skb) == -FBNIC_XDP_CONSUME) {
 				fbnic_put_pkt_buff(qt, pkt, 1);
+			} else if (skb == ERR_PTR(-FBNIC_XDP_REDIRECT)) {
+				redirect = true;
+			} else if (skb == ERR_PTR(-FBNIC_XDP_REDIRECT_ERR)) {
+				/* A broadcast may queue frames, then fail. XDP
+				 * consumed the packet, so it also counts as
+				 * received.
+				 */
+				redirect = true;
+				dropped++;
+				fbnic_put_pkt_buff(qt, pkt, 1);
 			} else {
 				if (!skb)
 					alloc_failed++;
@@ -1377,6 +1394,8 @@ static int fbnic_clean_rcq(struct fbnic_napi_vector *nv,
 
 	if (pkt_tail >= 0)
 		fbnic_pkt_commit_tail(nv, pkt_tail);
+	if (redirect)
+		xdp_do_flush();
 
 	/* Unmap and free processed buffers */
 	if (head0 >= 0)
-- 
2.56.0