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authorSridhar Samudrala <sridhar.samudrala@intel.com>2018-05-24 19:55:15 +0300
committerDavid S. Miller <davem@davemloft.net>2018-05-29 05:59:54 +0300
commitcfc80d9a11635404a40199a1c9471c96890f3f74 (patch)
treeda95be375f932bd726ea4e57a504cd6373fdfc8f /Documentation/networking
parent1ff78076d8dd182c883e6caa285479ae7db32ef8 (diff)
downloadlinux-cfc80d9a11635404a40199a1c9471c96890f3f74.tar.xz
net: Introduce net_failover driver
The net_failover driver provides an automated failover mechanism via APIs to create and destroy a failover master netdev and manages a primary and standby slave netdevs that get registered via the generic failover infrastructure. The failover netdev acts a master device and controls 2 slave devices. The original paravirtual interface gets registered as 'standby' slave netdev and a passthru/vf device with the same MAC gets registered as 'primary' slave netdev. Both 'standby' and 'failover' netdevs are associated with the same 'pci' device. The user accesses the network interface via 'failover' netdev. The 'failover' netdev chooses 'primary' netdev as default for transmits when it is available with link up and running. This can be used by paravirtual drivers to enable an alternate low latency datapath. It also enables hypervisor controlled live migration of a VM with direct attached VF 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>
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+.. SPDX-License-Identifier: GPL-2.0
+
+============
+NET_FAILOVER
+============
+
+Overview
+========
+
+The net_failover driver provides an automated failover mechanism via APIs
+to create and destroy a failover master netdev and mananges a primary and
+standby slave netdevs that get registered via the generic failover
+infrastructrure.
+
+The failover netdev acts a master device and controls 2 slave devices. The
+original paravirtual interface is registered as 'standby' slave netdev and
+a passthru/vf device with the same MAC gets registered as 'primary' slave
+netdev. Both 'standby' and 'failover' netdevs are associated with the same
+'pci' device. The user accesses the network interface via 'failover' netdev.
+The 'failover' netdev chooses 'primary' netdev as default for transmits when
+it is available with link up and running.
+
+This can be used by paravirtual drivers to enable an alternate low latency
+datapath. It also enables hypervisor controlled live migration of a VM with
+direct attached VF by failing over to the paravirtual datapath when the VF
+is unplugged.