ionic: add ndo_xdp_xmit

When our ndo_xdp_xmit is called we mark the buffer with
XDP_REDIRECT so we know to return it to the XDP stack for
cleaning.
Co-developed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/pensando/ionic/ionic_lif.c

@@ -1650,7 +1650,8 @@ static int ionic_init_nic_features(struct ionic_lif *lif)
 			      IFF_LIVE_ADDR_CHANGE;
 
 	netdev->xdp_features = NETDEV_XDP_ACT_BASIC    |
-			       NETDEV_XDP_ACT_REDIRECT;
+			       NETDEV_XDP_ACT_REDIRECT |
+			       NETDEV_XDP_ACT_NDO_XMIT;
 
 	return 0;
 }
@@ -2847,6 +2848,7 @@ static const struct net_device_ops ionic_netdev_ops = {
 	.ndo_eth_ioctl		= ionic_eth_ioctl,
 	.ndo_start_xmit		= ionic_start_xmit,
 	.ndo_bpf		= ionic_xdp,
+	.ndo_xdp_xmit		= ionic_xdp_xmit,
 	.ndo_get_stats64	= ionic_get_stats64,
 	.ndo_set_rx_mode	= ionic_ndo_set_rx_mode,
 	.ndo_set_features	= ionic_set_features,

drivers/net/ethernet/pensando/ionic/ionic_txrx.c

@@ -320,9 +320,13 @@ static void ionic_xdp_tx_desc_clean(struct ionic_queue *q,
 	buf_info = desc_info->bufs;
 	dma_unmap_single(dev, buf_info->dma_addr,
 			 buf_info->len, DMA_TO_DEVICE);
-	__free_pages(buf_info->page, 0);
+	if (desc_info->act == XDP_TX)
+		__free_pages(buf_info->page, 0);
 	buf_info->page = NULL;
 
+	if (desc_info->act == XDP_REDIRECT)
+		xdp_return_frame(desc_info->xdpf);
+
 	desc_info->nbufs = 0;
 	desc_info->xdpf = NULL;
 	desc_info->act = 0;
@@ -376,6 +380,63 @@ static int ionic_xdp_post_frame(struct net_device *netdev,
 	return 0;
 }
 
+int ionic_xdp_xmit(struct net_device *netdev, int n,
+		   struct xdp_frame **xdp_frames, u32 flags)
+{
+	struct ionic_lif *lif = netdev_priv(netdev);
+	struct ionic_queue *txq;
+	struct netdev_queue *nq;
+	int nxmit;
+	int space;
+	int cpu;
+	int qi;
+
+	if (unlikely(!test_bit(IONIC_LIF_F_UP, lif->state)))
+		return -ENETDOWN;
+
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+		return -EINVAL;
+
+	/* AdminQ is assumed on cpu 0, while we attempt to affinitize the
+	 * TxRx queue pairs 0..n-1 on cpus 1..n.  We try to keep with that
+	 * affinitization here, but of course irqbalance and friends might
+	 * have juggled things anyway, so we have to check for the 0 case.
+	 */
+	cpu = smp_processor_id();
+	qi = cpu ? (cpu - 1) % lif->nxqs : cpu;
+
+	txq = &lif->txqcqs[qi]->q;
+	nq = netdev_get_tx_queue(netdev, txq->index);
+	__netif_tx_lock(nq, cpu);
+	txq_trans_cond_update(nq);
+
+	if (netif_tx_queue_stopped(nq) ||
+	    unlikely(ionic_maybe_stop_tx(txq, 1))) {
+		__netif_tx_unlock(nq);
+		return -EIO;
+	}
+
+	space = min_t(int, n, ionic_q_space_avail(txq));
+	for (nxmit = 0; nxmit < space ; nxmit++) {
+		if (ionic_xdp_post_frame(netdev, txq, xdp_frames[nxmit],
+					 XDP_REDIRECT,
+					 virt_to_page(xdp_frames[nxmit]->data),
+					 0, false)) {
+			nxmit--;
+			break;
+		}
+	}
+
+	if (flags & XDP_XMIT_FLUSH)
+		ionic_dbell_ring(lif->kern_dbpage, txq->hw_type,
+				 txq->dbval | txq->head_idx);
+
+	ionic_maybe_stop_tx(txq, 4);
+	__netif_tx_unlock(nq);
+
+	return nxmit;
+}
+
 static bool ionic_run_xdp(struct ionic_rx_stats *stats,
 			  struct net_device *netdev,
 			  struct bpf_prog *xdp_prog,

drivers/net/ethernet/pensando/ionic/ionic_txrx.h

@@ -17,4 +17,5 @@ netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev);
 bool ionic_rx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info);
 bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info);
 
+int ionic_xdp_xmit(struct net_device *netdev, int n, struct xdp_frame **xdp, u32 flags);
 #endif /* _IONIC_TXRX_H_ */