[PATCH net-next v7 0/4] netdevsim: link and forward skbs between ports

[PATCH net-next v7 0/4] netdevsim: link and forward skbs between ports

[David Wei]

This patchset adds the ability to link two netdevsim ports together and
forward skbs between them, similar to veth. The goal is to use netdevsim
for testing features e.g. zero copy Rx using io_uring.

This feature was tested locally on QEMU, and a selftest is included.

---
v6->v7:
- change link syntax to netnsid:ifidx
- replace dev_get_by_index() with __dev_get_by_index()
- check for NULL peer when linking
- add a sysfs attribute for unlinking
- only update Tx stats if not dropped
- update selftest

v5->v6:
- reworked to link two netdevsims using sysfs attribute on the bus
  device instead of debugfs due to deadlock possibility if a netdevsim
  is removed during linking
- removed unnecessary patch maintaining a list of probed nsim_devs
- updated selftest

v4->v5:
- reduce nsim_dev_list_lock critical section
- fixed missing mutex unlock during unwind ladder
- rework nsim_dev_peer_write synchronization to take devlink lock as
  well as rtnl_lock
- return err msgs to user during linking if port doesn't exist or
  linking to self
- update tx stats outside of RCU lock

v3->v4:
- maintain a mutex protected list of probed nsim_devs instead of using
  nsim_bus_dev
- fixed synchronization issues by taking rtnl_lock
- track tx_dropped skbs

v2->v3:
- take lock when traversing nsim_bus_dev_list
- take device ref when getting a nsim_bus_dev
- return 0 if nsim_dev_peer_read cannot find the port
- address code formatting
- do not hard code values in selftests
- add Makefile for selftests

v1->v2:
- renamed debugfs file from "link" to "peer"
- replaced strstep() with sscanf() for consistency
- increased char[] buf sz to 22 for copying id + port from user
- added err msg w/ expected fmt when linking as a hint to user
- prevent linking port to itself
- protect peer ptr using RCU


David Wei (4):
  netdevsim: allow two netdevsim ports to be connected
  netdevsim: forward skbs from one connected port to another
  netdevsim: add selftest for forwarding skb between connected ports
  netdevsim: add Makefile for selftests

 MAINTAINERS                                   |   1 +
 drivers/net/netdevsim/bus.c                   | 132 ++++++++++++++++++
 drivers/net/netdevsim/netdev.c                |  39 +++++-
 drivers/net/netdevsim/netdevsim.h             |   3 +
 .../selftests/drivers/net/netdevsim/Makefile  |  18 +++
 .../selftests/drivers/net/netdevsim/peer.sh   | 127 +++++++++++++++++
 6 files changed, 315 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/drivers/net/netdevsim/Makefile
 create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer.sh

-- 
2.39.3

[PATCH net-next v7 1/4] netdevsim: allow two netdevsim ports to be connected

[David Wei]

Add two netdevsim bus attribute to sysfs:
/sys/bus/netdevsim/link_device
/sys/bus/netdevsim/unlink_device

Writing "A M B N" to link_device will link netdevsim M in netnsid A with
netdevsim N in netnsid B.

Writing "A M" to unlink_device will unlink netdevsim M in netnsid A from
its peer and vice versa, if any.

rtnl_lock is taken to ensure nothing changes during the linking.

Signed-off-by: David Wei <dw@davidwei.uk>
---
 drivers/net/netdevsim/bus.c       | 130 ++++++++++++++++++++++++++++++
 drivers/net/netdevsim/netdev.c    |  11 +++
 drivers/net/netdevsim/netdevsim.h |   2 +
 3 files changed, 143 insertions(+)

diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
index bcbc1e19edde..3162f88b88ec 100644
--- a/drivers/net/netdevsim/bus.c
+++ b/drivers/net/netdevsim/bus.c
@@ -232,9 +232,139 @@ del_device_store(const struct bus_type *bus, const char *buf, size_t count)
 }
 static BUS_ATTR_WO(del_device);
 
+static ssize_t link_device_store(const struct bus_type *bus, const char *buf, size_t count)
+{
+	unsigned int netnsid_a, netnsid_b, ifidx_a, ifidx_b;
+	struct netdevsim *nsim_a, *nsim_b;
+	struct net_device *dev_a, *dev_b;
+	struct net *ns_a, *ns_b;
+	int err;
+
+	err = sscanf(buf, "%u:%u %u:%u", &netnsid_a, &ifidx_a, &netnsid_b, &ifidx_b);
+	if (err != 4) {
+		pr_err("Format for linking two devices is \"netnsid_a:ifidx_a netnsid_b:ifidx_b\" (uint uint unit uint).\n");
+		return -EINVAL;
+	}
+
+	err = -EINVAL;
+	rtnl_lock();
+	ns_a = get_net_ns_by_id(current->nsproxy->net_ns, netnsid_a);
+	if (!ns_a) {
+		pr_err("Could not find netns with id: %u\n", netnsid_a);
+		goto out_unlock_rtnl;
+	}
+
+	dev_a = __dev_get_by_index(ns_a, ifidx_a);
+	if (!dev_a) {
+		pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx_a, netnsid_a);
+		goto out_put_netns_a;
+	}
+
+	if (!netdev_is_nsim(dev_a)) {
+		pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx_a, netnsid_a);
+		goto out_put_netns_a;
+	}
+
+	ns_b = get_net_ns_by_id(current->nsproxy->net_ns, netnsid_b);
+	if (!ns_b) {
+		pr_err("Could not find netns with id: %u\n", netnsid_b);
+		goto out_put_netns_a;
+	}
+
+	dev_b = __dev_get_by_index(ns_b, ifidx_b);
+	if (!dev_b) {
+		pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx_b, netnsid_b);
+		goto out_put_netns_b;
+	}
+
+	if (!netdev_is_nsim(dev_b)) {
+		pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx_b, netnsid_b);
+		goto out_put_netns_b;
+	}
+
+	err = 0;
+	nsim_a = netdev_priv(dev_a);
+	if (nsim_a->peer) {
+		pr_err("Netdevsim %u:%u is already linked\n", netnsid_a, ifidx_a);
+		goto out_put_netns_b;
+	}
+
+	nsim_b = netdev_priv(dev_b);
+	if (nsim_b->peer) {
+		pr_err("Netdevsim %u:%u is already linked\n", netnsid_b, ifidx_b);
+		goto out_put_netns_b;
+	}
+
+	rcu_assign_pointer(nsim_a->peer, nsim_b);
+	rcu_assign_pointer(nsim_b->peer, nsim_a);
+
+out_put_netns_b:
+	put_net(ns_b);
+out_put_netns_a:
+	put_net(ns_a);
+out_unlock_rtnl:
+	rtnl_unlock();
+
+	return !err ? count : err;
+}
+static BUS_ATTR_WO(link_device);
+
+static ssize_t unlink_device_store(const struct bus_type *bus, const char *buf, size_t count)
+{
+	struct netdevsim *nsim, *peer;
+	unsigned int netnsid, ifidx;
+	struct net_device *dev;
+	struct net *ns;
+	int err;
+
+	err = sscanf(buf, "%u:%u", &netnsid, &ifidx);
+	if (err != 2) {
+		pr_err("Format for unlinking a device is \"netnsid:ifidx\" (uint uint).\n");
+		return -EINVAL;
+	}
+
+	err = -EINVAL;
+	rtnl_lock();
+	ns = get_net_ns_by_id(current->nsproxy->net_ns, netnsid);
+	if (!ns) {
+		pr_err("Could not find netns with id: %u\n", netnsid);
+		goto out_unlock_rtnl;
+	}
+
+	dev = __dev_get_by_index(ns, ifidx);
+	if (!dev) {
+		pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx, netnsid);
+		goto out_put_netns;
+	}
+
+	if (!netdev_is_nsim(dev)) {
+		pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx, netnsid);
+		goto out_put_netns;
+	}
+
+	err = 0;
+	nsim = netdev_priv(dev);
+	if (!nsim->peer)
+		goto out_put_netns;
+	peer = nsim->peer;
+
+	RCU_INIT_POINTER(nsim->peer, NULL);
+	RCU_INIT_POINTER(peer->peer, NULL);
+
+out_put_netns:
+	put_net(ns);
+out_unlock_rtnl:
+	rtnl_unlock();
+
+	return !err ? count : err;
+}
+static BUS_ATTR_WO(unlink_device);
+
 static struct attribute *nsim_bus_attrs[] = {
 	&bus_attr_new_device.attr,
 	&bus_attr_del_device.attr,
+	&bus_attr_link_device.attr,
+	&bus_attr_unlink_device.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(nsim_bus);
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 77e8250282a5..969248ffeca8 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -394,6 +394,7 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
 	ns->nsim_dev = nsim_dev;
 	ns->nsim_dev_port = nsim_dev_port;
 	ns->nsim_bus_dev = nsim_dev->nsim_bus_dev;
+	RCU_INIT_POINTER(ns->peer, NULL);
 	SET_NETDEV_DEV(dev, &ns->nsim_bus_dev->dev);
 	SET_NETDEV_DEVLINK_PORT(dev, &nsim_dev_port->devlink_port);
 	nsim_ethtool_init(ns);
@@ -413,8 +414,13 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
 void nsim_destroy(struct netdevsim *ns)
 {
 	struct net_device *dev = ns->netdev;
+	struct netdevsim *peer;
 
 	rtnl_lock();
+	peer = rtnl_dereference(ns->peer);
+	if (peer)
+		RCU_INIT_POINTER(peer->peer, NULL);
+	RCU_INIT_POINTER(ns->peer, NULL);
 	unregister_netdevice(dev);
 	if (nsim_dev_port_is_pf(ns->nsim_dev_port)) {
 		nsim_macsec_teardown(ns);
@@ -427,6 +433,11 @@ void nsim_destroy(struct netdevsim *ns)
 	free_netdev(dev);
 }
 
+bool netdev_is_nsim(struct net_device *dev)
+{
+	return dev->netdev_ops == &nsim_netdev_ops;
+}
+
 static int nsim_validate(struct nlattr *tb[], struct nlattr *data[],
 			 struct netlink_ext_ack *extack)
 {
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 028c825b86db..c8b45b0d955e 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -125,11 +125,13 @@ struct netdevsim {
 	} udp_ports;
 
 	struct nsim_ethtool ethtool;
+	struct netdevsim __rcu *peer;
 };
 
 struct netdevsim *
 nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port);
 void nsim_destroy(struct netdevsim *ns);
+bool netdev_is_nsim(struct net_device *dev);
 
 void nsim_ethtool_init(struct netdevsim *ns);
 
-- 
2.39.3

[PATCH net-next v7 2/4] netdevsim: forward skbs from one connected port to another

[David Wei]

Forward skbs sent from one netdevsim port to its connected netdevsim
port using dev_forward_skb, in a spirit similar to veth.

Add a tx_dropped variable to struct netdevsim, tracking the number of
skbs that could not be forwarded using dev_forward_skb().

The xmit() function accessing the peer ptr is protected by an RCU read
critical section. The rcu_read_lock() is functionally redundant as since
v5.0 all softirqs are implicitly RCU read critical sections; but it is
useful for human readers.

If another CPU is concurrently in nsim_destroy(), then it will first set
the peer ptr to NULL. This does not affect any existing readers that
dereferenced a non-NULL peer. Then, in unregister_netdevice(), there is
a synchronize_rcu() before the netdev is actually unregistered and
freed. This ensures that any readers i.e. xmit() that got a non-NULL
peer will complete before the netdev is freed.

Any readers after the RCU_INIT_POINTER() but before synchronize_rcu()
will dereference NULL, making it safe.

The codepath to nsim_destroy() and nsim_create() takes both the newly
added nsim_dev_list_lock and rtnl_lock. This makes it safe with
concurrent calls to linking two netdevsims together.

Signed-off-by: David Wei <dw@davidwei.uk>
---
 drivers/net/netdevsim/netdev.c    | 28 +++++++++++++++++++++++-----
 drivers/net/netdevsim/netdevsim.h |  1 +
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 969248ffeca8..120a24d74d28 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -29,19 +29,37 @@
 static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct netdevsim *ns = netdev_priv(dev);
+	unsigned int len = skb->len;
+	struct netdevsim *peer_ns;
+	int ret = NETDEV_TX_OK;
 
 	if (!nsim_ipsec_tx(ns, skb))
 		goto out;
 
+	rcu_read_lock();
+	peer_ns = rcu_dereference(ns->peer);
+	if (!peer_ns)
+		goto out_stats;
+
+	skb_tx_timestamp(skb);
+	if (unlikely(dev_forward_skb(peer_ns->netdev, skb) == NET_RX_DROP))
+		ret = NET_XMIT_DROP;
+
+out_stats:
+	rcu_read_unlock();
 	u64_stats_update_begin(&ns->syncp);
-	ns->tx_packets++;
-	ns->tx_bytes += skb->len;
+	if (ret == NET_XMIT_DROP) {
+		ns->tx_dropped++;
+	} else {
+		ns->tx_packets++;
+		ns->tx_bytes += len;
+	}
 	u64_stats_update_end(&ns->syncp);
+	return ret;
 
 out:
 	dev_kfree_skb(skb);
-
-	return NETDEV_TX_OK;
+	return ret;
 }
 
 static void nsim_set_rx_mode(struct net_device *dev)
@@ -70,6 +88,7 @@ nsim_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 		start = u64_stats_fetch_begin(&ns->syncp);
 		stats->tx_bytes = ns->tx_bytes;
 		stats->tx_packets = ns->tx_packets;
+		stats->tx_dropped = ns->tx_dropped;
 	} while (u64_stats_fetch_retry(&ns->syncp, start));
 }
 
@@ -302,7 +321,6 @@ static void nsim_setup(struct net_device *dev)
 	eth_hw_addr_random(dev);
 
 	dev->tx_queue_len = 0;
-	dev->flags |= IFF_NOARP;
 	dev->flags &= ~IFF_MULTICAST;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE |
 			   IFF_NO_QUEUE;
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index c8b45b0d955e..553c4b9b4f63 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -98,6 +98,7 @@ struct netdevsim {
 
 	u64 tx_packets;
 	u64 tx_bytes;
+	u64 tx_dropped;
 	struct u64_stats_sync syncp;
 
 	struct nsim_bus_dev *nsim_bus_dev;
-- 
2.39.3

[PATCH net-next v7 3/4] netdevsim: add selftest for forwarding skb between connected ports

[David Wei]

Connect two netdevsim ports in different namespaces together, then send
packets between them using socat.

Signed-off-by: David Wei <dw@davidwei.uk>
---
 .../selftests/drivers/net/netdevsim/peer.sh   | 127 ++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer.sh

diff --git a/tools/testing/selftests/drivers/net/netdevsim/peer.sh b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
new file mode 100755
index 000000000000..05f3cefa53f3
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
@@ -0,0 +1,127 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+
+NSIM_DEV_1_ID=$((RANDOM % 1024))
+NSIM_DEV_1_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_1_ID
+NSIM_DEV_1_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_1_ID
+NSIM_DEV_2_ID=$((RANDOM % 1024))
+NSIM_DEV_2_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_2_ID
+NSIM_DEV_2_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_2_ID
+
+NSIM_DEV_SYS_NEW=/sys/bus/netdevsim/new_device
+NSIM_DEV_SYS_DEL=/sys/bus/netdevsim/del_device
+NSIM_DEV_SYS_LINK=/sys/bus/netdevsim/link_device
+NSIM_DEV_SYS_UNLINK=/sys/bus/netdevsim/unlink_device
+
+socat_check()
+{
+	if [ ! -x "$(command -v socat)" ]; then
+		echo "socat command not found. Skipping test"
+		return 1
+	fi
+
+	return 0
+}
+
+setup_ns()
+{
+	set -e
+	ip netns add nssv
+	ip netns add nscl
+
+	NSIM_DEV_1_NAME=$(find $NSIM_DEV_1_SYS/net -maxdepth 1 -type d ! \
+		-path $NSIM_DEV_1_SYS/net -exec basename {} \;)
+	NSIM_DEV_2_NAME=$(find $NSIM_DEV_2_SYS/net -maxdepth 1 -type d ! \
+		-path $NSIM_DEV_2_SYS/net -exec basename {} \;)
+
+	ip link set $NSIM_DEV_1_NAME netns nssv
+	ip link set $NSIM_DEV_2_NAME netns nscl
+
+	ip netns exec nssv ip addr add '192.168.1.1/24' dev $NSIM_DEV_1_NAME
+	ip netns exec nscl ip addr add '192.168.1.2/24' dev $NSIM_DEV_2_NAME
+
+	ip netns exec nssv ip link set dev $NSIM_DEV_1_NAME up
+	ip netns exec nscl ip link set dev $NSIM_DEV_2_NAME up
+	set +e
+}
+
+cleanup_ns()
+{
+	ip netns del nscl
+	ip netns del nssv
+}
+
+###
+### Code start
+###
+
+modprobe netdevsim
+
+# linking
+
+echo $NSIM_DEV_1_ID > $NSIM_DEV_SYS_NEW
+echo $NSIM_DEV_2_ID > $NSIM_DEV_SYS_NEW
+
+setup_ns
+
+NSIM_DEV_1_NETNSID=$(ip netns list-id | grep nssv | awk '{print $2}')
+NSIM_DEV_1_IFIDX=$(ip netns exec nssv cat /sys/class/net/$NSIM_DEV_1_NAME/ifindex)
+
+NSIM_DEV_2_NETNSID=$(ip netns list-id | grep nscl | awk '{print $2}')
+NSIM_DEV_2_IFIDX=$(ip netns exec nscl cat /sys/class/net/$NSIM_DEV_2_NAME/ifindex)
+
+echo "$NSIM_DEV_1_NETNSID:$NSIM_DEV_1_IFIDX $NSIM_DEV_2_NETNSID:20" > $NSIM_DEV_SYS_LINK 2>/dev/null
+if [ $? -eq 0 ]; then
+	echo "linking with non-existent netdevsim should fail"
+	exit 1
+fi
+
+echo "$NSIM_DEV_1_NETNSID:$NSIM_DEV_1_IFIDX 20:$NSIM_DEV_2_IFIDX" > $NSIM_DEV_SYS_LINK 2>/dev/null
+if [ $? -eq 0 ]; then
+	echo "linking with non-existent netnsid should fail"
+	exit 1
+fi
+
+echo "$NSIM_DEV_1_NETNSID:$NSIM_DEV_1_IFIDX $NSIM_DEV_2_NETNSID:$NSIM_DEV_2_IFIDX" > $NSIM_DEV_SYS_LINK
+if [ $? -ne 0 ]; then
+	echo "linking netdevsim1 with netdevsim2 should succeed"
+	exit 1
+fi
+
+# argument error checking
+
+echo "$NSIM_DEV_1_NETNSID:$NSIM_DEV_1_IFIDX $NSIM_DEV_2_NETNSID:a" > $NSIM_DEV_SYS_LINK 2>/dev/null
+if [ $? -eq 0 ]; then
+	echo "invalid arg should fail"
+	exit 1
+fi
+
+# send/recv packets
+
+socat_check || exit 4
+
+tmp_file=$(mktemp)
+ip netns exec nssv socat TCP-LISTEN:1234,fork $tmp_file &
+pid=$!
+res=0
+
+echo "HI" | ip netns exec nscl socat STDIN TCP:192.168.1.1:1234
+
+count=$(cat $tmp_file | wc -c)
+if [[ $count -ne 3 ]]; then
+	echo "expected 3 bytes, got $count"
+	res=1
+fi
+
+echo "$NSIM_DEV_1_NETNSID:$NSIM_DEV_1_IFIDX" > $NSIM_DEV_SYS_UNLINK
+
+echo $NSIM_DEV_2_ID > $NSIM_DEV_SYS_DEL
+
+kill $pid
+echo $NSIM_DEV_1_ID > $NSIM_DEV_SYS_DEL
+
+cleanup_ns
+
+modprobe -r netdevsim
+
+exit $res
-- 
2.39.3

[PATCH net-next v7 4/4] netdevsim: add Makefile for selftests

[David Wei]

Add a Makefile for netdevsim selftests and add selftests path to
MAINTAINERS

Signed-off-by: David Wei <dw@davidwei.uk>
---
 MAINTAINERS                                    |  1 +
 .../selftests/drivers/net/netdevsim/Makefile   | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/net/netdevsim/Makefile

diff --git a/MAINTAINERS b/MAINTAINERS
index 92152ac346c8..562af3dfd2d0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15082,6 +15082,7 @@ NETDEVSIM
 M:	Jakub Kicinski <kuba@kernel.org>
 S:	Maintained
 F:	drivers/net/netdevsim/*
+F:	tools/testing/selftests/drivers/net/netdevsim/*
 
 NETEM NETWORK EMULATOR
 M:	Stephen Hemminger <stephen@networkplumber.org>
diff --git a/tools/testing/selftests/drivers/net/netdevsim/Makefile b/tools/testing/selftests/drivers/net/netdevsim/Makefile
new file mode 100644
index 000000000000..5bace0b7fb57
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/netdevsim/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0+ OR MIT
+
+TEST_PROGS = devlink.sh \
+	devlink_in_netns.sh \
+	devlink_trap.sh \
+	ethtool-coalesce.sh \
+	ethtool-fec.sh \
+	ethtool-pause.sh \
+	ethtool-ring.sh \
+	fib.sh \
+	hw_stats_l3.sh \
+	nexthop.sh \
+	peer.sh \
+	psample.sh \
+	tc-mq-visibility.sh \
+	udp_tunnel_nic.sh \
+
+include ../../../lib.mk
-- 
2.39.3

Re: [PATCH net-next v7 1/4] netdevsim: allow two netdevsim ports to be connected

[kernel test robot]

Hi David,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Wei/netdevsim-allow-two-netdevsim-ports-to-be-connected/20240127-121234
base:   net-next/main
patch link:    https://lore.kernel.org/r/20240127040354.944744-2-dw%40davidwei.uk
patch subject: [PATCH net-next v7 1/4] netdevsim: allow two netdevsim ports to be connected
config: x86_64-randconfig-r122-20240127 (https://download.01.org/0day-ci/archive/20240128/202401280644.lnmk82jI-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240128/202401280644.lnmk82jI-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401280644.lnmk82jI-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/net/netdevsim/bus.c:349:14: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct netdevsim *peer @@     got struct netdevsim [noderef] __rcu *peer @@
   drivers/net/netdevsim/bus.c:349:14: sparse:     expected struct netdevsim *peer
   drivers/net/netdevsim/bus.c:349:14: sparse:     got struct netdevsim [noderef] __rcu *peer

vim +349 drivers/net/netdevsim/bus.c

   311	
   312	static ssize_t unlink_device_store(const struct bus_type *bus, const char *buf, size_t count)
   313	{
   314		struct netdevsim *nsim, *peer;
   315		unsigned int netnsid, ifidx;
   316		struct net_device *dev;
   317		struct net *ns;
   318		int err;
   319	
   320		err = sscanf(buf, "%u:%u", &netnsid, &ifidx);
   321		if (err != 2) {
   322			pr_err("Format for unlinking a device is \"netnsid:ifidx\" (uint uint).\n");
   323			return -EINVAL;
   324		}
   325	
   326		err = -EINVAL;
   327		rtnl_lock();
   328		ns = get_net_ns_by_id(current->nsproxy->net_ns, netnsid);
   329		if (!ns) {
   330			pr_err("Could not find netns with id: %u\n", netnsid);
   331			goto out_unlock_rtnl;
   332		}
   333	
   334		dev = __dev_get_by_index(ns, ifidx);
   335		if (!dev) {
   336			pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx, netnsid);
   337			goto out_put_netns;
   338		}
   339	
   340		if (!netdev_is_nsim(dev)) {
   341			pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx, netnsid);
   342			goto out_put_netns;
   343		}
   344	
   345		err = 0;
   346		nsim = netdev_priv(dev);
   347		if (!nsim->peer)
   348			goto out_put_netns;
 > 349		peer = nsim->peer;
   350	
   351		RCU_INIT_POINTER(nsim->peer, NULL);
   352		RCU_INIT_POINTER(peer->peer, NULL);
   353	
   354	out_put_netns:
   355		put_net(ns);
   356	out_unlock_rtnl:
   357		rtnl_unlock();
   358	
   359		return !err ? count : err;
   360	}
   361	static BUS_ATTR_WO(unlink_device);
   362	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net-next v7 3/4] netdevsim: add selftest for forwarding skb between connected ports

[Simon Horman]

On Fri, Jan 26, 2024 at 08:03:53PM -0800, David Wei wrote:
> Connect two netdevsim ports in different namespaces together, then send
> packets between them using socat.
> 
> Signed-off-by: David Wei <dw@davidwei.uk>
> ---
>  .../selftests/drivers/net/netdevsim/peer.sh   | 127 ++++++++++++++++++
>  1 file changed, 127 insertions(+)
>  create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer.sh
> 
> diff --git a/tools/testing/selftests/drivers/net/netdevsim/peer.sh b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
> new file mode 100755
> index 000000000000..05f3cefa53f3
> --- /dev/null
> +++ b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
> @@ -0,0 +1,127 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +NSIM_DEV_1_ID=$((RANDOM % 1024))
> +NSIM_DEV_1_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_1_ID
> +NSIM_DEV_1_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_1_ID
> +NSIM_DEV_2_ID=$((RANDOM % 1024))
> +NSIM_DEV_2_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_2_ID
> +NSIM_DEV_2_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_2_ID

nit: NSIM_DEV_1_DFS and SIM_DEV_2_DFS appear to be unused.

Flagged by shellcheck.

...

Re: [PATCH net-next v7 3/4] netdevsim: add selftest for forwarding skb between connected ports

[David Wei]

On 2024-01-29 12:34, Simon Horman wrote:
> On Fri, Jan 26, 2024 at 08:03:53PM -0800, David Wei wrote:
>> Connect two netdevsim ports in different namespaces together, then send
>> packets between them using socat.
>>
>> Signed-off-by: David Wei <dw@davidwei.uk>
>> ---
>>  .../selftests/drivers/net/netdevsim/peer.sh   | 127 ++++++++++++++++++
>>  1 file changed, 127 insertions(+)
>>  create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer.sh
>>
>> diff --git a/tools/testing/selftests/drivers/net/netdevsim/peer.sh b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
>> new file mode 100755
>> index 000000000000..05f3cefa53f3
>> --- /dev/null
>> +++ b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
>> @@ -0,0 +1,127 @@
>> +#!/bin/bash
>> +# SPDX-License-Identifier: GPL-2.0-only
>> +
>> +NSIM_DEV_1_ID=$((RANDOM % 1024))
>> +NSIM_DEV_1_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_1_ID
>> +NSIM_DEV_1_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_1_ID
>> +NSIM_DEV_2_ID=$((RANDOM % 1024))
>> +NSIM_DEV_2_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_2_ID
>> +NSIM_DEV_2_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_2_ID
> 
> nit: NSIM_DEV_1_DFS and SIM_DEV_2_DFS appear to be unused.
> 
> Flagged by shellcheck.
> 
> ...

Hi Simon, thanks for flagging this, these were leftover from previous
changes. I'll remove them in the next version.

Re: [PATCH net-next v7 3/4] netdevsim: add selftest for forwarding skb between connected ports

[Simon Horman]

On Tue, Jan 30, 2024 at 10:57:45AM -0800, David Wei wrote:
> On 2024-01-29 12:34, Simon Horman wrote:
> > On Fri, Jan 26, 2024 at 08:03:53PM -0800, David Wei wrote:
> >> Connect two netdevsim ports in different namespaces together, then send
> >> packets between them using socat.
> >>
> >> Signed-off-by: David Wei <dw@davidwei.uk>
> >> ---
> >>  .../selftests/drivers/net/netdevsim/peer.sh   | 127 ++++++++++++++++++
> >>  1 file changed, 127 insertions(+)
> >>  create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer.sh
> >>
> >> diff --git a/tools/testing/selftests/drivers/net/netdevsim/peer.sh b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
> >> new file mode 100755
> >> index 000000000000..05f3cefa53f3
> >> --- /dev/null
> >> +++ b/tools/testing/selftests/drivers/net/netdevsim/peer.sh
> >> @@ -0,0 +1,127 @@
> >> +#!/bin/bash
> >> +# SPDX-License-Identifier: GPL-2.0-only
> >> +
> >> +NSIM_DEV_1_ID=$((RANDOM % 1024))
> >> +NSIM_DEV_1_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_1_ID
> >> +NSIM_DEV_1_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_1_ID
> >> +NSIM_DEV_2_ID=$((RANDOM % 1024))
> >> +NSIM_DEV_2_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_DEV_2_ID
> >> +NSIM_DEV_2_DFS=/sys/kernel/debug/netdevsim/netdevsim$NSIM_DEV_2_ID
> > 
> > nit: NSIM_DEV_1_DFS and SIM_DEV_2_DFS appear to be unused.
> > 
> > Flagged by shellcheck.
> > 
> > ...
> 
> Hi Simon, thanks for flagging this, these were leftover from previous
> changes. I'll remove them in the next version.

Thanks David,

much appreciated.