switchdev: Add support for flood control

Allow devices supporting this feature to control the flooding of unknown
unicast traffic, by making switchdev infrastructure propagate this setting
to the switch driver.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
index 0714fe5..ce510e1 100644
--- a/Documentation/networking/switchdev.txt
+++ b/Documentation/networking/switchdev.txt
@@ -298,6 +298,9 @@
 of ports scale in the L2 domain as the device is much more efficient at
 flooding packets that software.
 
+If supported by the device, flood control can be offloaded to it, preventing
+certain netdevs from flooding unicast traffic for which there is no FDB entry.
+
 IGMP Snooping
 ^^^^^^^^^^^^^
 
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 1eb76956..8950d39 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -746,7 +746,7 @@
 		.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
 	};
 	u16 mode = BRIDGE_MODE_UNDEF;
-	u32 mask = BR_LEARNING | BR_LEARNING_SYNC;
+	u32 mask = BR_LEARNING | BR_LEARNING_SYNC | BR_FLOOD;
 	int err;
 
 	err = switchdev_port_attr_get(dev, &attr);
@@ -817,6 +817,9 @@
 			err = switchdev_port_br_setflag(dev, attr,
 							BR_LEARNING_SYNC);
 			break;
+		case IFLA_BRPORT_UNICAST_FLOOD:
+			err = switchdev_port_br_setflag(dev, attr, BR_FLOOD);
+			break;
 		default:
 			err = -EOPNOTSUPP;
 			break;