tsnep: Support XDP BPF program setup

Implement setup of BPF programs for XDP RX path with command
XDP_SETUP_PROG of ndo_bpf(). This is the final step for XDP RX path
support.

There is no need to reinit the RX queues as they are always prepared for
XDP.

Additionally remove $(tsnep-y) from $(tsnep-objs) because it is added
automatically.

Test results with A53 1.2GHz:

XDP_DROP (samples/bpf/xdp1)
proto 17:     883878 pkt/s

XDP_TX (samples/bpf/xdp2)
proto 17:     255693 pkt/s

XDP_REDIRECT (samples/bpf/xdpsock)
 sock0@eth2:0 rxdrop xdp-drv
                   pps            pkts           1.00
rx                 855,582        5,404,523
tx                 0              0

XDP_REDIRECT (samples/bpf/xdp_redirect)
eth2->eth1         613,267 rx/s   0 err,drop/s   613,272 xmit/s
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/engleder/Makefile

@@ -6,5 +6,5 @@
 obj-$(CONFIG_TSNEP) += tsnep.o
 
 tsnep-objs := tsnep_main.o tsnep_ethtool.o tsnep_ptp.o tsnep_tc.o \
-	      tsnep_rxnfc.o $(tsnep-y)
+	      tsnep_rxnfc.o tsnep_xdp.o
 tsnep-$(CONFIG_TSNEP_SELFTESTS) += tsnep_selftests.o

drivers/net/ethernet/engleder/tsnep.h

@@ -211,6 +211,9 @@ int tsnep_rxnfc_add_rule(struct tsnep_adapter *adapter,
 int tsnep_rxnfc_del_rule(struct tsnep_adapter *adapter,
 			 struct ethtool_rxnfc *cmd);
 
+int tsnep_xdp_setup_prog(struct tsnep_adapter *adapter, struct bpf_prog *prog,
+			 struct netlink_ext_ack *extack);
+
 #if IS_ENABLED(CONFIG_TSNEP_SELFTESTS)
 int tsnep_ethtool_get_test_count(void);
 void tsnep_ethtool_get_test_strings(u8 *data);

drivers/net/ethernet/engleder/tsnep_main.c

@@ -1614,6 +1614,18 @@ static ktime_t tsnep_netdev_get_tstamp(struct net_device *netdev,
 	return ns_to_ktime(timestamp);
 }
 
+static int tsnep_netdev_bpf(struct net_device *dev, struct netdev_bpf *bpf)
+{
+	struct tsnep_adapter *adapter = netdev_priv(dev);
+
+	switch (bpf->command) {
+	case XDP_SETUP_PROG:
+		return tsnep_xdp_setup_prog(adapter, bpf->prog, bpf->extack);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static struct tsnep_tx *tsnep_xdp_get_tx(struct tsnep_adapter *adapter, u32 cpu)
 {
 	if (cpu >= TSNEP_MAX_QUEUES)
@@ -1674,6 +1686,7 @@ static const struct net_device_ops tsnep_netdev_ops = {
 	.ndo_set_features = tsnep_netdev_set_features,
 	.ndo_get_tstamp = tsnep_netdev_get_tstamp,
 	.ndo_setup_tc = tsnep_tc_setup,
+	.ndo_bpf = tsnep_netdev_bpf,
 	.ndo_xdp_xmit = tsnep_netdev_xdp_xmit,
 };
 

drivers/net/ethernet/engleder/tsnep_xdp.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2022 Gerhard Engleder <gerhard@engleder-embedded.com> */
+
+#include <linux/if_vlan.h>
+#include <net/xdp_sock_drv.h>
+
+#include "tsnep.h"
+
+int tsnep_xdp_setup_prog(struct tsnep_adapter *adapter, struct bpf_prog *prog,
+			 struct netlink_ext_ack *extack)
+{
+	struct bpf_prog *old_prog;
+
+	old_prog = xchg(&adapter->xdp_prog, prog);
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	return 0;
+}