s390/qeth: Reset address notification in case of buffer overflow

In case hardware sends more device-to-bridge-address-change notfications
than the qeth-l2 driver can handle, the hardware will send an overflow
event and then stop sending any events. It expects software to flush its
FDB and start over again. Re-enabling address-change-notification will
report all current addresses.

In order to re-enable address-change-notification this patch defines
the functions qeth_l2_dev2br_an_set() and qeth_l2_dev2br_an_set_cb
to enable or disable dev-to-bridge-address-notification.

A following patch will use the learning_sync bridgeport flag to trigger
enabling or disabling of address-change-notification, so we define
priv->brport_features to store the current setting. BRIDGE_INFO and
ADDR_INFO functionality are mutually exclusive, whereas ADDR_INFO and
qeth_l2_vnicc* can be used together.

Alternative implementations to handle buffer overflow:
Just re-enabling notification and adding all newly reported addresses
would cover any lost 'add' events, but not the lost 'delete' events.
Then these invalid addresses would stay in the bridge FDB as long as the
device exists.
Setting the net device down and up, would be an alternative, but is a bit
drastic. If the net device has many secondary addresses this will create
many delete/add events at its peers which could de-stabilize the
network segment.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/s390/net/qeth_l2.h b/drivers/s390/net/qeth_l2.h
index adf25c9fd2b3..cc95675c8bc4 100644
--- a/drivers/s390/net/qeth_l2.h
+++ b/drivers/s390/net/qeth_l2.h
@@ -23,7 +23,7 @@ int qeth_l2_vnicc_set_state(struct qeth_card *card, u32 vnicc, bool state);
 int qeth_l2_vnicc_get_state(struct qeth_card *card, u32 vnicc, bool *state);
 int qeth_l2_vnicc_set_timeout(struct qeth_card *card, u32 timeout);
 int qeth_l2_vnicc_get_timeout(struct qeth_card *card, u32 *timeout);
-bool qeth_l2_vnicc_is_in_use(struct qeth_card *card);
+bool qeth_bridgeport_allowed(struct qeth_card *card);
 
 struct qeth_mac {
 	u8 mac_addr[ETH_ALEN];