[PATCH net-next 0/3] s390/qeth: Add bridge to switchdev LEARNING_SYNC

[PATCH net-next 0/3] s390/qeth: Add bridge to switchdev LEARNING_SYNC

[Karsten Graul]

Please apply the following patch series for qeth to netdev's net-next tree.

The netlink bridgeport attribute LEARNING_SYNC can be used to enable
qeth interfaces to report MAC addresses that are reachable via this
qeth interface to the attached software bridge via switchdev
notifiers SWITCHDEV_FDB_ADD_TO_BRIDGE and SWITCHDEV_FDB_DEL_TO_BRIDGE.

Extend this support of LEARNING_SYNC to the bridge to switchdev notifiers
SWITCHDEV_FDB_ADD_TO_DEVICE and SWITCHDEV_FDB_DEL_TO_DEVICE.

Add the capability to sync MAC addresses that are learned by a
north-facing, non-isolated bridgeport of a software bridge to
south-facing, isolated bridgeports. This enables the software bridge to
influence south to north traffic steering in hardware.

Alexandra Winter (3):
  s390/qeth: Register switchdev event handler
  s390/qeth: Switchdev event handler
  s390/qeth: Update MACs of LEARNING_SYNC device

 drivers/s390/net/Kconfig        |   1 +
 drivers/s390/net/qeth_l2_main.c | 239 +++++++++++++++++++++++++++++++-
 2 files changed, 237 insertions(+), 3 deletions(-)

-- 
2.25.1

[PATCH net-next 1/3] s390/qeth: Register switchdev event handler

[Karsten Graul]

From: Alexandra Winter <wintera@linux.ibm.com>

Conditionally register a qeth_l2 switchdev_event handler to handle bridge
to device switchdev events, when at least one qeth interface has the
bridgeport attribute LEARNING_SYNC enabled.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 drivers/s390/net/qeth_l2_main.c | 43 ++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 69afc0311dd1..3d02d35df5d3 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -717,6 +717,31 @@ static int qeth_l2_dev2br_an_set(struct qeth_card *card, bool enable)
 	return rc;
 }
 
+static refcount_t qeth_l2_switchdev_notify_refcnt;
+
+/* Called under rtnl_lock */
+static void qeth_l2_br2dev_get(void)
+{
+	if (!refcount_inc_not_zero(&qeth_l2_switchdev_notify_refcnt)) {
+		/* tbd: register_switchdev_notifier(&qeth_l2_sw_notifier); */
+		refcount_set(&qeth_l2_switchdev_notify_refcnt, 1);
+		QETH_DBF_MESSAGE(2, "qeth_l2_sw_notifier registered\n");
+	}
+	QETH_DBF_TEXT_(SETUP, 2, "b2d+%04d",
+		       qeth_l2_switchdev_notify_refcnt.refs.counter);
+}
+
+/* Called under rtnl_lock */
+static void qeth_l2_br2dev_put(void)
+{
+	if (refcount_dec_and_test(&qeth_l2_switchdev_notify_refcnt)) {
+		/* tbd: unregister_switchdev_notifier(&qeth_l2_sw_notifier); */
+		QETH_DBF_MESSAGE(2, "qeth_l2_sw_notifier unregistered\n");
+	}
+	QETH_DBF_TEXT_(SETUP, 2, "b2d-%04d",
+		       qeth_l2_switchdev_notify_refcnt.refs.counter);
+}
+
 static int qeth_l2_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 				  struct net_device *dev, u32 filter_mask,
 				  int nlflags)
@@ -810,16 +835,19 @@ static int qeth_l2_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 	} else if (enable) {
 		qeth_l2_set_pnso_mode(card, QETH_PNSO_ADDR_INFO);
 		rc = qeth_l2_dev2br_an_set(card, true);
-		if (rc)
+		if (rc) {
 			qeth_l2_set_pnso_mode(card, QETH_PNSO_NONE);
-		else
+		} else {
 			priv->brport_features |= BR_LEARNING_SYNC;
+			qeth_l2_br2dev_get();
+		}
 	} else {
 		rc = qeth_l2_dev2br_an_set(card, false);
 		if (!rc) {
 			qeth_l2_set_pnso_mode(card, QETH_PNSO_NONE);
 			priv->brport_features ^= BR_LEARNING_SYNC;
 			qeth_l2_dev2br_fdb_flush(card);
+			qeth_l2_br2dev_put();
 		}
 	}
 	mutex_unlock(&card->sbp_lock);
@@ -2072,6 +2100,7 @@ static int qeth_l2_probe_device(struct ccwgroup_device *gdev)
 static void qeth_l2_remove_device(struct ccwgroup_device *gdev)
 {
 	struct qeth_card *card = dev_get_drvdata(&gdev->dev);
+	struct qeth_priv *priv;
 
 	if (gdev->dev.type != &qeth_l2_devtype)
 		device_remove_groups(&gdev->dev, qeth_l2_attr_groups);
@@ -2083,8 +2112,15 @@ static void qeth_l2_remove_device(struct ccwgroup_device *gdev)
 		qeth_set_offline(card, card->discipline, false);
 
 	cancel_work_sync(&card->close_dev_work);
-	if (card->dev->reg_state == NETREG_REGISTERED)
+	if (card->dev->reg_state == NETREG_REGISTERED) {
+		priv = netdev_priv(card->dev);
+		if (priv->brport_features & BR_LEARNING_SYNC) {
+			rtnl_lock();
+			qeth_l2_br2dev_put();
+			rtnl_unlock();
+		}
 		unregister_netdev(card->dev);
+	}
 }
 
 static int qeth_l2_set_online(struct qeth_card *card, bool carrier_ok)
@@ -2207,6 +2243,7 @@ EXPORT_SYMBOL_GPL(qeth_l2_discipline);
 static int __init qeth_l2_init(void)
 {
 	pr_info("register layer 2 discipline\n");
+	refcount_set(&qeth_l2_switchdev_notify_refcnt, 0);
 	return 0;
 }
 
-- 
2.25.1

[PATCH net-next 2/3] s390/qeth: Switchdev event handler

[Karsten Graul]

From: Alexandra Winter <wintera@linux.ibm.com>

QETH HiperSockets devices with LEARNING_SYNC capability can be used
to construct a linux bridge with:
2 isolated southbound interfaces:
     a) a default network interface
     b) a LEARNING-SYNC HiperSockets interface
and 1 non-isolated northbound interface. This is called a 'HiperSockets
Converged Interface' (HSCI).
The existing LEARNING_SYNC functionality is used to update the bridge fdb
with MAC addresses that should be sent-out via the HiperSockets interface,
instead of the default network interface.

Add handling of switchdev events SWITCHDEV_FDB_ADD_TO_DEVICE and
SWITCHDEV_FDB_DEL_TO_DEVICE to the qeth LEARNING_SYNC functionality. Thus
if the northbound bridgeport of an HSCI doesn't only have a single static
MAC address, but instead is a learning bridgeport, work is enqueued, so
the HiperSockets virtual switch (that is external to this Linux instance)
can update its fdb.

When BRIDGE is a loadable module, QETH_L2 mustn't be built-in:

drivers/s390/net/qeth_l2_main.o: in function 'qeth_l2_switchdev_event':
drivers/s390/net/qeth_l2_main.c:927: undefined reference to
'br_port_flag_is_set'

Add Kconfig dependency to enforce usable configurations.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 drivers/s390/net/Kconfig        |  1 +
 drivers/s390/net/qeth_l2_main.c | 83 +++++++++++++++++++++++++++++++--
 2 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/net/Kconfig b/drivers/s390/net/Kconfig
index cff91b4f1a76..9c67b97faba2 100644
--- a/drivers/s390/net/Kconfig
+++ b/drivers/s390/net/Kconfig
@@ -74,6 +74,7 @@ config QETH_L2
 	def_tristate y
 	prompt "qeth layer 2 device support"
 	depends on QETH
+	depends on BRIDGE || BRIDGE=n
 	help
 	  Select this option to be able to run qeth devices in layer 2 mode.
 	  To compile as a module, choose M. The module name is qeth_l2.
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 3d02d35df5d3..e38a1befce3f 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -717,15 +717,79 @@ static int qeth_l2_dev2br_an_set(struct qeth_card *card, bool enable)
 	return rc;
 }
 
+static const struct net_device_ops qeth_l2_netdev_ops;
+
+static bool qeth_l2_must_learn(struct net_device *netdev,
+			       struct net_device *dstdev)
+{
+	struct qeth_priv *priv;
+
+	priv = netdev_priv(netdev);
+	return (netdev != dstdev &&
+		(priv->brport_features & BR_LEARNING_SYNC) &&
+		!(br_port_flag_is_set(netdev, BR_ISOLATED) &&
+		  br_port_flag_is_set(dstdev, BR_ISOLATED)) &&
+		netdev->netdev_ops == &qeth_l2_netdev_ops);
+}
+
+/* Called under rtnl_lock */
+static int qeth_l2_switchdev_event(struct notifier_block *unused,
+				   unsigned long event, void *ptr)
+{
+	struct net_device *dstdev, *brdev, *lowerdev;
+	struct switchdev_notifier_fdb_info *fdb_info;
+	struct switchdev_notifier_info *info = ptr;
+	struct list_head *iter;
+	struct qeth_card *card;
+
+	if (!(event == SWITCHDEV_FDB_ADD_TO_DEVICE ||
+	      event == SWITCHDEV_FDB_DEL_TO_DEVICE))
+		return NOTIFY_DONE;
+
+	dstdev = switchdev_notifier_info_to_dev(info);
+	brdev = netdev_master_upper_dev_get_rcu(dstdev);
+	if (!brdev || !netif_is_bridge_master(brdev))
+		return NOTIFY_DONE;
+	fdb_info = container_of(info,
+				struct switchdev_notifier_fdb_info,
+				info);
+	iter = &brdev->adj_list.lower;
+	lowerdev = netdev_next_lower_dev_rcu(brdev, &iter);
+	while (lowerdev) {
+		if (qeth_l2_must_learn(lowerdev, dstdev)) {
+			card = lowerdev->ml_priv;
+			QETH_CARD_TEXT_(card, 4, "b2dqw%03x", event);
+			/* tbd: rc = qeth_l2_br2dev_queue_work(brdev, lowerdev,
+			 *				       dstdev, event,
+			 *				       fdb_info->addr);
+			 */
+		}
+		lowerdev = netdev_next_lower_dev_rcu(brdev, &iter);
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block qeth_l2_sw_notifier = {
+		.notifier_call = qeth_l2_switchdev_event,
+};
+
 static refcount_t qeth_l2_switchdev_notify_refcnt;
 
 /* Called under rtnl_lock */
 static void qeth_l2_br2dev_get(void)
 {
+	int rc;
+
 	if (!refcount_inc_not_zero(&qeth_l2_switchdev_notify_refcnt)) {
-		/* tbd: register_switchdev_notifier(&qeth_l2_sw_notifier); */
-		refcount_set(&qeth_l2_switchdev_notify_refcnt, 1);
-		QETH_DBF_MESSAGE(2, "qeth_l2_sw_notifier registered\n");
+		rc = register_switchdev_notifier(&qeth_l2_sw_notifier);
+		if (rc) {
+			QETH_DBF_MESSAGE(2,
+					 "failed to register qeth_l2_sw_notifier: %d\n",
+					 rc);
+		} else {
+			refcount_set(&qeth_l2_switchdev_notify_refcnt, 1);
+			QETH_DBF_MESSAGE(2, "qeth_l2_sw_notifier registered\n");
+		}
 	}
 	QETH_DBF_TEXT_(SETUP, 2, "b2d+%04d",
 		       qeth_l2_switchdev_notify_refcnt.refs.counter);
@@ -734,9 +798,18 @@ static void qeth_l2_br2dev_get(void)
 /* Called under rtnl_lock */
 static void qeth_l2_br2dev_put(void)
 {
+	int rc;
+
 	if (refcount_dec_and_test(&qeth_l2_switchdev_notify_refcnt)) {
-		/* tbd: unregister_switchdev_notifier(&qeth_l2_sw_notifier); */
-		QETH_DBF_MESSAGE(2, "qeth_l2_sw_notifier unregistered\n");
+		rc = unregister_switchdev_notifier(&qeth_l2_sw_notifier);
+		if (rc) {
+			QETH_DBF_MESSAGE(2,
+					 "failed to unregister qeth_l2_sw_notifier: %d\n",
+					 rc);
+		} else {
+			QETH_DBF_MESSAGE(2,
+					 "qeth_l2_sw_notifier unregistered\n");
+		}
 	}
 	QETH_DBF_TEXT_(SETUP, 2, "b2d-%04d",
 		       qeth_l2_switchdev_notify_refcnt.refs.counter);
-- 
2.25.1

[PATCH net-next 3/3] s390/qeth: Update MACs of LEARNING_SYNC device

[Karsten Graul]

From: Alexandra Winter <wintera@linux.ibm.com>

Update the MAC addresses that are registered with a LEARNING_SYNC qeth
device with the events announced by the attached software bridge.

Typically the LEARNING_SYNC qeth bridge port has an isolated sibling (the
default interface of an 'HiperSockets Converged Interface' (HSCI)). Update
the MACs of isolated siblings as well, to avoid unnecessary flooding in
the attached virtualized switches.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 drivers/s390/net/qeth_l2_main.c | 131 +++++++++++++++++++++++++++++++-
 1 file changed, 127 insertions(+), 4 deletions(-)

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index e38a1befce3f..4871f712b874 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -717,6 +717,15 @@ static int qeth_l2_dev2br_an_set(struct qeth_card *card, bool enable)
 	return rc;
 }
 
+struct qeth_l2_br2dev_event_work {
+	struct work_struct work;
+	struct net_device *br_dev;
+	struct net_device *lsync_dev;
+	struct net_device *dst_dev;
+	unsigned long event;
+	unsigned char addr[ETH_ALEN];
+};
+
 static const struct net_device_ops qeth_l2_netdev_ops;
 
 static bool qeth_l2_must_learn(struct net_device *netdev,
@@ -732,6 +741,116 @@ static bool qeth_l2_must_learn(struct net_device *netdev,
 		netdev->netdev_ops == &qeth_l2_netdev_ops);
 }
 
+/**
+ *	qeth_l2_br2dev_worker() - update local MACs
+ *	@work: bridge to device FDB update
+ *
+ *	Update local MACs of a learning_sync bridgeport so it can receive
+ *	messages for a destination port.
+ *	In case of an isolated learning_sync port, also update its isolated
+ *	siblings.
+ */
+static void qeth_l2_br2dev_worker(struct work_struct *work)
+{
+	struct qeth_l2_br2dev_event_work *br2dev_event_work =
+		container_of(work, struct qeth_l2_br2dev_event_work, work);
+	struct net_device *lsyncdev = br2dev_event_work->lsync_dev;
+	struct net_device *dstdev = br2dev_event_work->dst_dev;
+	struct net_device *brdev = br2dev_event_work->br_dev;
+	unsigned long event = br2dev_event_work->event;
+	unsigned char *addr = br2dev_event_work->addr;
+	struct qeth_card *card = lsyncdev->ml_priv;
+	struct net_device *lowerdev;
+	struct list_head *iter;
+	int err = 0;
+
+	kfree(br2dev_event_work);
+	QETH_CARD_TEXT_(card, 4, "b2dw%04x", event);
+	QETH_CARD_TEXT_(card, 4, "ma%012lx", ether_addr_to_u64(addr));
+
+	rcu_read_lock();
+	/* Verify preconditions are still valid: */
+	if (!netif_is_bridge_port(lsyncdev) ||
+	    brdev != netdev_master_upper_dev_get_rcu(lsyncdev))
+		goto unlock;
+	if (!qeth_l2_must_learn(lsyncdev, dstdev))
+		goto unlock;
+
+	if (br_port_flag_is_set(lsyncdev, BR_ISOLATED)) {
+		/* Update lsyncdev and its isolated sibling(s): */
+		iter = &brdev->adj_list.lower;
+		lowerdev = netdev_next_lower_dev_rcu(brdev, &iter);
+		while (lowerdev) {
+			if (br_port_flag_is_set(lowerdev, BR_ISOLATED)) {
+				switch (event) {
+				case SWITCHDEV_FDB_ADD_TO_DEVICE:
+					err = dev_uc_add(lowerdev, addr);
+					break;
+				case SWITCHDEV_FDB_DEL_TO_DEVICE:
+					err = dev_uc_del(lowerdev, addr);
+					break;
+				default:
+					break;
+				}
+				if (err) {
+					QETH_CARD_TEXT(card, 2, "b2derris");
+					QETH_CARD_TEXT_(card, 2,
+							"err%02x%03d", event,
+							lowerdev->ifindex);
+				}
+			}
+			lowerdev = netdev_next_lower_dev_rcu(brdev, &iter);
+		}
+	} else {
+		switch (event) {
+		case SWITCHDEV_FDB_ADD_TO_DEVICE:
+			err = dev_uc_add(lsyncdev, addr);
+			break;
+		case SWITCHDEV_FDB_DEL_TO_DEVICE:
+			err = dev_uc_del(lsyncdev, addr);
+			break;
+		default:
+			break;
+		}
+		if (err)
+			QETH_CARD_TEXT_(card, 2, "b2derr%02x", event);
+	}
+
+unlock:
+	rcu_read_unlock();
+	dev_put(brdev);
+	dev_put(lsyncdev);
+	dev_put(dstdev);
+}
+
+static int qeth_l2_br2dev_queue_work(struct net_device *brdev,
+				     struct net_device *lsyncdev,
+				     struct net_device *dstdev,
+				     unsigned long event,
+				     const unsigned char *addr)
+{
+	struct qeth_l2_br2dev_event_work *worker_data;
+	struct qeth_card *card;
+
+	worker_data = kzalloc(sizeof(*worker_data), GFP_ATOMIC);
+	if (!worker_data)
+		return -ENOMEM;
+	INIT_WORK(&worker_data->work, qeth_l2_br2dev_worker);
+	worker_data->br_dev = brdev;
+	worker_data->lsync_dev = lsyncdev;
+	worker_data->dst_dev = dstdev;
+	worker_data->event = event;
+	ether_addr_copy(worker_data->addr, addr);
+
+	card = lsyncdev->ml_priv;
+	/* Take a reference on the sw port devices and the bridge */
+	dev_hold(brdev);
+	dev_hold(lsyncdev);
+	dev_hold(dstdev);
+	queue_work(card->event_wq, &worker_data->work);
+	return 0;
+}
+
 /* Called under rtnl_lock */
 static int qeth_l2_switchdev_event(struct notifier_block *unused,
 				   unsigned long event, void *ptr)
@@ -741,6 +860,7 @@ static int qeth_l2_switchdev_event(struct notifier_block *unused,
 	struct switchdev_notifier_info *info = ptr;
 	struct list_head *iter;
 	struct qeth_card *card;
+	int rc;
 
 	if (!(event == SWITCHDEV_FDB_ADD_TO_DEVICE ||
 	      event == SWITCHDEV_FDB_DEL_TO_DEVICE))
@@ -759,10 +879,13 @@ static int qeth_l2_switchdev_event(struct notifier_block *unused,
 		if (qeth_l2_must_learn(lowerdev, dstdev)) {
 			card = lowerdev->ml_priv;
 			QETH_CARD_TEXT_(card, 4, "b2dqw%03x", event);
-			/* tbd: rc = qeth_l2_br2dev_queue_work(brdev, lowerdev,
-			 *				       dstdev, event,
-			 *				       fdb_info->addr);
-			 */
+			rc = qeth_l2_br2dev_queue_work(brdev, lowerdev,
+						       dstdev, event,
+						       fdb_info->addr);
+			if (rc) {
+				QETH_CARD_TEXT(card, 2, "b2dqwerr");
+				return NOTIFY_BAD;
+			}
 		}
 		lowerdev = netdev_next_lower_dev_rcu(brdev, &iter);
 	}
-- 
2.25.1

Re: [PATCH net-next 0/3] s390/qeth: Add bridge to switchdev LEARNING_SYNC

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Fri,  6 Aug 2021 17:26:00 +0200 you wrote:
> Please apply the following patch series for qeth to netdev's net-next tree.
> 
> The netlink bridgeport attribute LEARNING_SYNC can be used to enable
> qeth interfaces to report MAC addresses that are reachable via this
> qeth interface to the attached software bridge via switchdev
> notifiers SWITCHDEV_FDB_ADD_TO_BRIDGE and SWITCHDEV_FDB_DEL_TO_BRIDGE.
> 
> [...]

Here is the summary with links:
  - [net-next,1/3] s390/qeth: Register switchdev event handler
    https://git.kernel.org/netdev/net-next/c/60bb1089467d
  - [net-next,2/3] s390/qeth: Switchdev event handler
    https://git.kernel.org/netdev/net-next/c/4e20e73e631a
  - [net-next,3/3] s390/qeth: Update MACs of LEARNING_SYNC device
    https://git.kernel.org/netdev/net-next/c/f7936b7b2663

You are awesome, thank you!
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