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Commit 30c8bd5a authored by Sridhar Samudrala's avatar Sridhar Samudrala Committed by David S. Miller
Browse files

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: default avatarSridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cb160394

Documentation/networking/failover.rst

0 → 100644
+18 −0
Original line number Diff line number Diff line 
.. SPDX-License-Identifier: GPL-2.0



========

FAILOVER

========



Overview

========



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 live migration of VMs with direct attached VFs by

failing over to the paravirtual datapath when the VF is unplugged.

MAINTAINERS

+8 −0
Original line number Diff line number Diff line
@@ -5411,6 +5411,14 @@ S: Maintained 
F:	Documentation/hwmon/f71805f

F:	drivers/hwmon/f71805f.c



FAILOVER MODULE

M:	Sridhar Samudrala <sridhar.samudrala@intel.com>

L:	netdev@vger.kernel.org

S:	Supported

F:	net/core/failover.c

F:	include/net/failover.h

F:	Documentation/networking/failover.rst



FANOTIFY

M:	Jan Kara <jack@suse.cz>

R:	Amir Goldstein <amir73il@gmail.com>

include/linux/netdevice.h

+16 −0
Original line number Diff line number Diff line
@@ -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)

{

include/net/failover.h

0 → 100644
+36 −0
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/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2018, Intel Corporation. */



#ifndef _FAILOVER_H

#define _FAILOVER_H



#include <linux/netdevice.h>



struct failover_ops {

	int (*slave_pre_register)(struct net_device *slave_dev,

				  struct net_device *failover_dev);

	int (*slave_register)(struct net_device *slave_dev,

			      struct net_device *failover_dev);

	int (*slave_pre_unregister)(struct net_device *slave_dev,

				    struct net_device *failover_dev);

	int (*slave_unregister)(struct net_device *slave_dev,

				struct net_device *failover_dev);

	int (*slave_link_change)(struct net_device *slave_dev,

				 struct net_device *failover_dev);

	int (*slave_name_change)(struct net_device *slave_dev,

				 struct net_device *failover_dev);

	rx_handler_result_t (*slave_handle_frame)(struct sk_buff **pskb);

};



struct failover {

	struct list_head list;

	struct net_device __rcu *failover_dev;

	struct failover_ops __rcu *ops;

};



struct failover *failover_register(struct net_device *dev,

				   struct failover_ops *ops);

void failover_unregister(struct failover *failover);

int failover_slave_unregister(struct net_device *slave_dev);



#endif /* _FAILOVER_H */

net/Kconfig

+13 −0
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@@ -432,6 +432,19 @@ config MAY_USE_DEVLINK 
config PAGE_POOL

       bool



config FAILOVER

	tristate "Generic failover module"

	help

	  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 live

	  migration of VMs with direct attached VFs by failing over to the

	  paravirtual datapath when the VF is unplugged.



endif   # if NET



# Used by archs to tell that they support BPF JIT compiler plus which flavour.