net: ethernet: ti: fix netdevice stats for XDP

Align netdevice statistics when the device is running in XDP mode
to other upstream drivers. In particular report to user-space rx
packets even if they are not forwarded to the networking stack
(XDP_PASS) but if they are redirected (XDP_REDIRECT), dropped (XDP_DROP)
or sent back using the same interface (XDP_TX). This patch allows the
system administrator to verify the device is receiving data correctly.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/a457cb17dd9c58c116d64ee34c354b2e89c0ff8f.1612375372.git.lorenzo@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ti/cpsw.c

@@ -403,12 +403,10 @@ static void cpsw_rx_handler(void *token, int len, int status)
 		xdp_prepare_buff(&xdp, pa, headroom, size, false);
 
 		port = priv->emac_port + cpsw->data.dual_emac;
-		ret = cpsw_run_xdp(priv, ch, &xdp, page, port);
+		ret = cpsw_run_xdp(priv, ch, &xdp, page, port, &len);
 		if (ret != CPSW_XDP_PASS)
 			goto requeue;
 
-		/* XDP prog might have changed packet data and boundaries */
-		len = xdp.data_end - xdp.data;
 		headroom = xdp.data - xdp.data_hard_start;
 
 		/* XDP prog can modify vlan tag, so can't use encap header */

drivers/net/ethernet/ti/cpsw_new.c

@@ -345,12 +345,10 @@ static void cpsw_rx_handler(void *token, int len, int status)
 
 		xdp_prepare_buff(&xdp, pa, headroom, size, false);
 
-		ret = cpsw_run_xdp(priv, ch, &xdp, page, priv->emac_port);
+		ret = cpsw_run_xdp(priv, ch, &xdp, page, priv->emac_port, &len);
 		if (ret != CPSW_XDP_PASS)
 			goto requeue;
 
-		/* XDP prog might have changed packet data and boundaries */
-		len = xdp.data_end - xdp.data;
 		headroom = xdp.data - xdp.data_hard_start;
 
 		/* XDP prog can modify vlan tag, so can't use encap header */

drivers/net/ethernet/ti/cpsw_priv.c

@@ -1323,7 +1323,7 @@ int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf,
 }
 
 int cpsw_run_xdp(struct cpsw_priv *priv, int ch, struct xdp_buff *xdp,
-		 struct page *page, int port)
+		 struct page *page, int port, int *len)
 {
 	struct cpsw_common *cpsw = priv->cpsw;
 	struct net_device *ndev = priv->ndev;
@@ -1341,10 +1341,13 @@ int cpsw_run_xdp(struct cpsw_priv *priv, int ch, struct xdp_buff *xdp,
 	}
 
 	act = bpf_prog_run_xdp(prog, xdp);
+	/* XDP prog might have changed packet data and boundaries */
+	*len = xdp->data_end - xdp->data;
+
 	switch (act) {
 	case XDP_PASS:
 		ret = CPSW_XDP_PASS;
-		break;
+		goto out;
 	case XDP_TX:
 		xdpf = xdp_convert_buff_to_frame(xdp);
 		if (unlikely(!xdpf))
@@ -1370,8 +1373,13 @@ int cpsw_run_xdp(struct cpsw_priv *priv, int ch, struct xdp_buff *xdp,
 		trace_xdp_exception(ndev, prog, act);
 		fallthrough;	/* handle aborts by dropping packet */
 	case XDP_DROP:
+		ndev->stats.rx_bytes += *len;
+		ndev->stats.rx_packets++;
 		goto drop;
 	}
+
+	ndev->stats.rx_bytes += *len;
+	ndev->stats.rx_packets++;
 out:
 	rcu_read_unlock();
 	return ret;

drivers/net/ethernet/ti/cpsw_priv.h

@@ -438,7 +438,7 @@ int cpsw_ndo_bpf(struct net_device *ndev, struct netdev_bpf *bpf);
 int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf,
 		      struct page *page, int port);
 int cpsw_run_xdp(struct cpsw_priv *priv, int ch, struct xdp_buff *xdp,
-		 struct page *page, int port);
+		 struct page *page, int port, int *len);
 irqreturn_t cpsw_tx_interrupt(int irq, void *dev_id);
 irqreturn_t cpsw_rx_interrupt(int irq, void *dev_id);
 irqreturn_t cpsw_misc_interrupt(int irq, void *dev_id);