s390/qeth: Switchdev event handler

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/s390/net/Kconfig b/drivers/s390/net/Kconfig
index cff91b4..9c67b97 100644 (file)
--- 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 3d02d35..e38a1be 100644 (file)
--- 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);