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>hifive-unleashed-5.1
Sridhar Samudrala
David S. Miller
parent
cb1603948a
commit
30c8bd5aa8
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@ -0,0 +1,18 @@
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.. SPDX-License-Identifier: GPL-2.0
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========
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FAILOVER
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========
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Overview
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========
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The failover module provides a generic interface for paravirtual drivers
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to register a netdev and a set of ops with a failover instance. The ops
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are used as event handlers that get called to handle netdev register/
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unregister/link change/name change events on slave pci ethernet devices
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with the same mac address as the failover netdev.
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This enables paravirtual drivers to use a VF as an accelerated low latency
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datapath. It also allows live migration of VMs with direct attached VFs by
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failing over to the paravirtual datapath when the VF is unplugged.
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@ -5411,6 +5411,14 @@ S: Maintained
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F: Documentation/hwmon/f71805f
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F: drivers/hwmon/f71805f.c
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FAILOVER MODULE
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M: Sridhar Samudrala <sridhar.samudrala@intel.com>
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L: netdev@vger.kernel.org
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S: Supported
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F: net/core/failover.c
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F: include/net/failover.h
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F: Documentation/networking/failover.rst
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FANOTIFY
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M: Jan Kara <jack@suse.cz>
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R: Amir Goldstein <amir73il@gmail.com>
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@ -1425,6 +1425,8 @@ struct net_device_ops {
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* entity (i.e. the master device for bridged veth)
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* @IFF_MACSEC: device is a MACsec device
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* @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook
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* @IFF_FAILOVER: device is a failover master device
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* @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
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*/
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enum netdev_priv_flags {
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IFF_802_1Q_VLAN = 1<<0,
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@ -1454,6 +1456,8 @@ enum netdev_priv_flags {
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IFF_PHONY_HEADROOM = 1<<24,
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IFF_MACSEC = 1<<25,
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IFF_NO_RX_HANDLER = 1<<26,
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IFF_FAILOVER = 1<<27,
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IFF_FAILOVER_SLAVE = 1<<28,
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};
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#define IFF_802_1Q_VLAN IFF_802_1Q_VLAN
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@ -1482,6 +1486,8 @@ enum netdev_priv_flags {
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#define IFF_RXFH_CONFIGURED IFF_RXFH_CONFIGURED
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#define IFF_MACSEC IFF_MACSEC
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#define IFF_NO_RX_HANDLER IFF_NO_RX_HANDLER
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#define IFF_FAILOVER IFF_FAILOVER
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#define IFF_FAILOVER_SLAVE IFF_FAILOVER_SLAVE
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/**
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* struct net_device - The DEVICE structure.
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@ -4336,6 +4342,16 @@ static inline bool netif_is_rxfh_configured(const struct net_device *dev)
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return dev->priv_flags & IFF_RXFH_CONFIGURED;
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}
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static inline bool netif_is_failover(const struct net_device *dev)
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{
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return dev->priv_flags & IFF_FAILOVER;
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}
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static inline bool netif_is_failover_slave(const struct net_device *dev)
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{
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return dev->priv_flags & IFF_FAILOVER_SLAVE;
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}
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/* This device needs to keep skb dst for qdisc enqueue or ndo_start_xmit() */
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static inline void netif_keep_dst(struct net_device *dev)
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{
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@ -0,0 +1,36 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2018, Intel Corporation. */
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#ifndef _FAILOVER_H
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#define _FAILOVER_H
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#include <linux/netdevice.h>
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struct failover_ops {
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int (*slave_pre_register)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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int (*slave_register)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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int (*slave_pre_unregister)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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int (*slave_unregister)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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int (*slave_link_change)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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int (*slave_name_change)(struct net_device *slave_dev,
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struct net_device *failover_dev);
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rx_handler_result_t (*slave_handle_frame)(struct sk_buff **pskb);
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};
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struct failover {
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struct list_head list;
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struct net_device __rcu *failover_dev;
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struct failover_ops __rcu *ops;
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};
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struct failover *failover_register(struct net_device *dev,
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struct failover_ops *ops);
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void failover_unregister(struct failover *failover);
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int failover_slave_unregister(struct net_device *slave_dev);
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#endif /* _FAILOVER_H */
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13
net/Kconfig
13
net/Kconfig
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@ -432,6 +432,19 @@ config MAY_USE_DEVLINK
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config PAGE_POOL
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bool
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config FAILOVER
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tristate "Generic failover module"
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help
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The failover module provides a generic interface for paravirtual
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drivers to register a netdev and a set of ops with a failover
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instance. The ops are used as event handlers that get called to
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handle netdev register/unregister/link change/name change events
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on slave pci ethernet devices with the same mac address as the
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failover netdev. This enables paravirtual drivers to use a
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VF as an accelerated low latency datapath. It also allows live
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migration of VMs with direct attached VFs by failing over to the
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paravirtual datapath when the VF is unplugged.
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endif # if NET
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# Used by archs to tell that they support BPF JIT compiler plus which flavour.
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@ -31,3 +31,4 @@ obj-$(CONFIG_DST_CACHE) += dst_cache.o
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obj-$(CONFIG_HWBM) += hwbm.o
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obj-$(CONFIG_NET_DEVLINK) += devlink.o
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obj-$(CONFIG_GRO_CELLS) += gro_cells.o
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obj-$(CONFIG_FAILOVER) += failover.o
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@ -0,0 +1,315 @@
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2018, Intel Corporation. */
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/* A common module to handle registrations and notifications for paravirtual
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* drivers to enable accelerated datapath and support VF live migration.
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*
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* The notifier and event handling code is based on netvsc driver.
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*/
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#include <linux/module.h>
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#include <linux/etherdevice.h>
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#include <uapi/linux/if_arp.h>
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#include <linux/rtnetlink.h>
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#include <linux/if_vlan.h>
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#include <net/failover.h>
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static LIST_HEAD(failover_list);
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static DEFINE_SPINLOCK(failover_lock);
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static struct net_device *failover_get_bymac(u8 *mac, struct failover_ops **ops)
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{
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struct net_device *failover_dev;
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struct failover *failover;
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spin_lock(&failover_lock);
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list_for_each_entry(failover, &failover_list, list) {
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failover_dev = rtnl_dereference(failover->failover_dev);
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if (ether_addr_equal(failover_dev->perm_addr, mac)) {
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*ops = rtnl_dereference(failover->ops);
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spin_unlock(&failover_lock);
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return failover_dev;
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}
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}
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spin_unlock(&failover_lock);
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return NULL;
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}
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/**
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* failover_slave_register - Register a slave netdev
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*
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* @slave_dev: slave netdev that is being registered
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*
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* Registers a slave device to a failover instance. Only ethernet devices
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* are supported.
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*/
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static int failover_slave_register(struct net_device *slave_dev)
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{
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struct netdev_lag_upper_info lag_upper_info;
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struct net_device *failover_dev;
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struct failover_ops *fops;
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int err;
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if (slave_dev->type != ARPHRD_ETHER)
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goto done;
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ASSERT_RTNL();
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failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
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if (!failover_dev)
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goto done;
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if (fops && fops->slave_pre_register &&
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fops->slave_pre_register(slave_dev, failover_dev))
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goto done;
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err = netdev_rx_handler_register(slave_dev, fops->slave_handle_frame,
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failover_dev);
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if (err) {
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netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n",
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err);
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goto done;
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}
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lag_upper_info.tx_type = NETDEV_LAG_TX_TYPE_ACTIVEBACKUP;
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err = netdev_master_upper_dev_link(slave_dev, failover_dev, NULL,
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&lag_upper_info, NULL);
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if (err) {
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netdev_err(slave_dev, "can not set failover device %s (err = %d)\n",
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failover_dev->name, err);
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goto err_upper_link;
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}
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slave_dev->priv_flags |= IFF_FAILOVER_SLAVE;
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if (fops && fops->slave_register &&
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!fops->slave_register(slave_dev, failover_dev))
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return NOTIFY_OK;
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netdev_upper_dev_unlink(slave_dev, failover_dev);
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slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE;
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err_upper_link:
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netdev_rx_handler_unregister(slave_dev);
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done:
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return NOTIFY_DONE;
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}
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/**
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* failover_slave_unregister - Unregister a slave netdev
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*
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* @slave_dev: slave netdev that is being unregistered
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*
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* Unregisters a slave device from a failover instance.
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*/
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int failover_slave_unregister(struct net_device *slave_dev)
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{
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struct net_device *failover_dev;
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struct failover_ops *fops;
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if (!netif_is_failover_slave(slave_dev))
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goto done;
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ASSERT_RTNL();
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failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
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if (!failover_dev)
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goto done;
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if (fops && fops->slave_pre_unregister &&
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fops->slave_pre_unregister(slave_dev, failover_dev))
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goto done;
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netdev_rx_handler_unregister(slave_dev);
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netdev_upper_dev_unlink(slave_dev, failover_dev);
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slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE;
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if (fops && fops->slave_unregister &&
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!fops->slave_unregister(slave_dev, failover_dev))
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return NOTIFY_OK;
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done:
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return NOTIFY_DONE;
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}
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EXPORT_SYMBOL_GPL(failover_slave_unregister);
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static int failover_slave_link_change(struct net_device *slave_dev)
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{
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struct net_device *failover_dev;
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struct failover_ops *fops;
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if (!netif_is_failover_slave(slave_dev))
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goto done;
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ASSERT_RTNL();
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failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
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if (!failover_dev)
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goto done;
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if (!netif_running(failover_dev))
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goto done;
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if (fops && fops->slave_link_change &&
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!fops->slave_link_change(slave_dev, failover_dev))
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return NOTIFY_OK;
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done:
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return NOTIFY_DONE;
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}
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static int failover_slave_name_change(struct net_device *slave_dev)
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{
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struct net_device *failover_dev;
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struct failover_ops *fops;
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if (!netif_is_failover_slave(slave_dev))
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goto done;
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ASSERT_RTNL();
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failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
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if (!failover_dev)
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goto done;
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if (!netif_running(failover_dev))
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goto done;
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if (fops && fops->slave_name_change &&
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!fops->slave_name_change(slave_dev, failover_dev))
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return NOTIFY_OK;
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done:
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return NOTIFY_DONE;
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}
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static int
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failover_event(struct notifier_block *this, unsigned long event, void *ptr)
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{
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struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
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/* Skip parent events */
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if (netif_is_failover(event_dev))
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return NOTIFY_DONE;
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switch (event) {
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case NETDEV_REGISTER:
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return failover_slave_register(event_dev);
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case NETDEV_UNREGISTER:
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return failover_slave_unregister(event_dev);
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case NETDEV_UP:
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case NETDEV_DOWN:
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case NETDEV_CHANGE:
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return failover_slave_link_change(event_dev);
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case NETDEV_CHANGENAME:
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return failover_slave_name_change(event_dev);
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default:
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return NOTIFY_DONE;
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}
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}
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static struct notifier_block failover_notifier = {
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.notifier_call = failover_event,
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};
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static void
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failover_existing_slave_register(struct net_device *failover_dev)
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{
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struct net *net = dev_net(failover_dev);
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struct net_device *dev;
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rtnl_lock();
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for_each_netdev(net, dev) {
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if (netif_is_failover(dev))
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continue;
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if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr))
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failover_slave_register(dev);
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}
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rtnl_unlock();
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}
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/**
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* failover_register - Register a failover instance
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*
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* @dev: failover netdev
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* @ops: failover ops
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*
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* Allocate and register a failover instance for a failover netdev. ops
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* provides handlers for slave device register/unregister/link change/
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* name change events.
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*
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* Return: pointer to failover instance
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*/
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struct failover *failover_register(struct net_device *dev,
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struct failover_ops *ops)
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{
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struct failover *failover;
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if (dev->type != ARPHRD_ETHER)
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return ERR_PTR(-EINVAL);
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failover = kzalloc(sizeof(*failover), GFP_KERNEL);
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if (!failover)
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return ERR_PTR(-ENOMEM);
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rcu_assign_pointer(failover->ops, ops);
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dev_hold(dev);
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dev->priv_flags |= IFF_FAILOVER;
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rcu_assign_pointer(failover->failover_dev, dev);
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spin_lock(&failover_lock);
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list_add_tail(&failover->list, &failover_list);
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spin_unlock(&failover_lock);
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netdev_info(dev, "failover master:%s registered\n", dev->name);
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failover_existing_slave_register(dev);
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return failover;
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}
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EXPORT_SYMBOL_GPL(failover_register);
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/**
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* failover_unregister - Unregister a failover instance
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*
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* @failover: pointer to failover instance
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*
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* Unregisters and frees a failover instance.
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*/
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void failover_unregister(struct failover *failover)
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{
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struct net_device *failover_dev;
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failover_dev = rcu_dereference(failover->failover_dev);
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netdev_info(failover_dev, "failover master:%s unregistered\n",
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failover_dev->name);
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failover_dev->priv_flags &= ~IFF_FAILOVER;
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dev_put(failover_dev);
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spin_lock(&failover_lock);
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list_del(&failover->list);
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spin_unlock(&failover_lock);
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kfree(failover);
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}
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EXPORT_SYMBOL_GPL(failover_unregister);
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static __init int
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failover_init(void)
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{
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register_netdevice_notifier(&failover_notifier);
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return 0;
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}
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module_init(failover_init);
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static __exit
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void failover_exit(void)
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{
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unregister_netdevice_notifier(&failover_notifier);
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}
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module_exit(failover_exit);
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MODULE_DESCRIPTION("Generic failover infrastructure/interface");
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MODULE_LICENSE("GPL v2");
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