net: Introduce generic failover module

The failover module provides a generic interface for paravirtual drivers
to register a netdev and a set of ops with a failover instance. The ops
are used as event handlers that get called to handle netdev register/
unregister/link change/name change events on slave pci ethernet devices
with the same mac address as the failover netdev.

This enables paravirtual drivers to use a VF as an accelerated low latency
datapath. It also allows migration of VMs with direct attached VFs by
failing over to the paravirtual datapath when the VF is unplugged.

Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8452f72087ef..f45b1a4e37ab 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1425,6 +1425,8 @@ struct net_device_ops {
  *      entity (i.e. the master device for bridged veth)
  * @IFF_MACSEC: device is a MACsec device
  * @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook
+ * @IFF_FAILOVER: device is a failover master device
+ * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
  */
 enum netdev_priv_flags {
         IFF_802_1Q_VLAN                 = 1<<0,
@@ -1454,6 +1456,8 @@ enum netdev_priv_flags {
         IFF_PHONY_HEADROOM              = 1<<24,
         IFF_MACSEC                      = 1<<25,
         IFF_NO_RX_HANDLER               = 1<<26,
+        IFF_FAILOVER                    = 1<<27,
+        IFF_FAILOVER_SLAVE              = 1<<28,
 };
 
 #define IFF_802_1Q_VLAN                 IFF_802_1Q_VLAN
@@ -1482,6 +1486,8 @@ enum netdev_priv_flags {
 #define IFF_RXFH_CONFIGURED             IFF_RXFH_CONFIGURED
 #define IFF_MACSEC                      IFF_MACSEC
 #define IFF_NO_RX_HANDLER               IFF_NO_RX_HANDLER
+#define IFF_FAILOVER                    IFF_FAILOVER
+#define IFF_FAILOVER_SLAVE              IFF_FAILOVER_SLAVE
 
 /**
  *      struct net_device - The DEVICE structure.
@@ -4336,6 +4342,16 @@ static inline bool netif_is_rxfh_configured(const struct net_device *dev)
         return dev->priv_flags & IFF_RXFH_CONFIGURED;
 }
 
+static inline bool netif_is_failover(const struct net_device *dev)
+{
+        return dev->priv_flags & IFF_FAILOVER;
+}
+
+static inline bool netif_is_failover_slave(const struct net_device *dev)
+{
+        return dev->priv_flags & IFF_FAILOVER_SLAVE;
+}
+
 /* This device needs to keep skb dst for qdisc enqueue or ndo_start_xmit() */
 static inline void netif_keep_dst(struct net_device *dev)
 {