From 30c8bd5aa8b2c78546c3e52337101b9c85879320 Mon Sep 17 00:00:00 2001 From: Sridhar Samudrala Date: Thu, 24 May 2018 09:55:13 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/Kconfig | 13 +++ net/core/Makefile | 1 + net/core/failover.c | 315 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 329 insertions(+) create mode 100644 net/core/failover.c (limited to 'net') diff --git a/net/Kconfig b/net/Kconfig index ba554cedb615..f738a6f27665 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -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. diff --git a/net/core/Makefile b/net/core/Makefile index 7080417f8bc8..80175e6a2eb8 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -31,3 +31,4 @@ obj-$(CONFIG_DST_CACHE) += dst_cache.o obj-$(CONFIG_HWBM) += hwbm.o obj-$(CONFIG_NET_DEVLINK) += devlink.o obj-$(CONFIG_GRO_CELLS) += gro_cells.o +obj-$(CONFIG_FAILOVER) += failover.o diff --git a/net/core/failover.c b/net/core/failover.c new file mode 100644 index 000000000000..4a92a98ccce9 --- /dev/null +++ b/net/core/failover.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2018, Intel Corporation. */ + +/* A common module to handle registrations and notifications for paravirtual + * drivers to enable accelerated datapath and support VF live migration. + * + * The notifier and event handling code is based on netvsc driver. + */ + +#include +#include +#include +#include +#include +#include + +static LIST_HEAD(failover_list); +static DEFINE_SPINLOCK(failover_lock); + +static struct net_device *failover_get_bymac(u8 *mac, struct failover_ops **ops) +{ + struct net_device *failover_dev; + struct failover *failover; + + spin_lock(&failover_lock); + list_for_each_entry(failover, &failover_list, list) { + failover_dev = rtnl_dereference(failover->failover_dev); + if (ether_addr_equal(failover_dev->perm_addr, mac)) { + *ops = rtnl_dereference(failover->ops); + spin_unlock(&failover_lock); + return failover_dev; + } + } + spin_unlock(&failover_lock); + return NULL; +} + +/** + * failover_slave_register - Register a slave netdev + * + * @slave_dev: slave netdev that is being registered + * + * Registers a slave device to a failover instance. Only ethernet devices + * are supported. + */ +static int failover_slave_register(struct net_device *slave_dev) +{ + struct netdev_lag_upper_info lag_upper_info; + struct net_device *failover_dev; + struct failover_ops *fops; + int err; + + if (slave_dev->type != ARPHRD_ETHER) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops); + if (!failover_dev) + goto done; + + if (fops && fops->slave_pre_register && + fops->slave_pre_register(slave_dev, failover_dev)) + goto done; + + err = netdev_rx_handler_register(slave_dev, fops->slave_handle_frame, + failover_dev); + if (err) { + netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n", + err); + goto done; + } + + lag_upper_info.tx_type = NETDEV_LAG_TX_TYPE_ACTIVEBACKUP; + err = netdev_master_upper_dev_link(slave_dev, failover_dev, NULL, + &lag_upper_info, NULL); + if (err) { + netdev_err(slave_dev, "can not set failover device %s (err = %d)\n", + failover_dev->name, err); + goto err_upper_link; + } + + slave_dev->priv_flags |= IFF_FAILOVER_SLAVE; + + if (fops && fops->slave_register && + !fops->slave_register(slave_dev, failover_dev)) + return NOTIFY_OK; + + netdev_upper_dev_unlink(slave_dev, failover_dev); + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; +err_upper_link: + netdev_rx_handler_unregister(slave_dev); +done: + return NOTIFY_DONE; +} + +/** + * failover_slave_unregister - Unregister a slave netdev + * + * @slave_dev: slave netdev that is being unregistered + * + * Unregisters a slave device from a failover instance. + */ +int failover_slave_unregister(struct net_device *slave_dev) +{ + struct net_device *failover_dev; + struct failover_ops *fops; + + if (!netif_is_failover_slave(slave_dev)) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops); + if (!failover_dev) + goto done; + + if (fops && fops->slave_pre_unregister && + fops->slave_pre_unregister(slave_dev, failover_dev)) + goto done; + + netdev_rx_handler_unregister(slave_dev); + netdev_upper_dev_unlink(slave_dev, failover_dev); + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; + + if (fops && fops->slave_unregister && + !fops->slave_unregister(slave_dev, failover_dev)) + return NOTIFY_OK; + +done: + return NOTIFY_DONE; +} +EXPORT_SYMBOL_GPL(failover_slave_unregister); + +static int failover_slave_link_change(struct net_device *slave_dev) +{ + struct net_device *failover_dev; + struct failover_ops *fops; + + if (!netif_is_failover_slave(slave_dev)) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops); + if (!failover_dev) + goto done; + + if (!netif_running(failover_dev)) + goto done; + + if (fops && fops->slave_link_change && + !fops->slave_link_change(slave_dev, failover_dev)) + return NOTIFY_OK; + +done: + return NOTIFY_DONE; +} + +static int failover_slave_name_change(struct net_device *slave_dev) +{ + struct net_device *failover_dev; + struct failover_ops *fops; + + if (!netif_is_failover_slave(slave_dev)) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops); + if (!failover_dev) + goto done; + + if (!netif_running(failover_dev)) + goto done; + + if (fops && fops->slave_name_change && + !fops->slave_name_change(slave_dev, failover_dev)) + return NOTIFY_OK; + +done: + return NOTIFY_DONE; +} + +static int +failover_event(struct notifier_block *this, unsigned long event, void *ptr) +{ + struct net_device *event_dev = netdev_notifier_info_to_dev(ptr); + + /* Skip parent events */ + if (netif_is_failover(event_dev)) + return NOTIFY_DONE; + + switch (event) { + case NETDEV_REGISTER: + return failover_slave_register(event_dev); + case NETDEV_UNREGISTER: + return failover_slave_unregister(event_dev); + case NETDEV_UP: + case NETDEV_DOWN: + case NETDEV_CHANGE: + return failover_slave_link_change(event_dev); + case NETDEV_CHANGENAME: + return failover_slave_name_change(event_dev); + default: + return NOTIFY_DONE; + } +} + +static struct notifier_block failover_notifier = { + .notifier_call = failover_event, +}; + +static void +failover_existing_slave_register(struct net_device *failover_dev) +{ + struct net *net = dev_net(failover_dev); + struct net_device *dev; + + rtnl_lock(); + for_each_netdev(net, dev) { + if (netif_is_failover(dev)) + continue; + if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr)) + failover_slave_register(dev); + } + rtnl_unlock(); +} + +/** + * failover_register - Register a failover instance + * + * @dev: failover netdev + * @ops: failover ops + * + * Allocate and register a failover instance for a failover netdev. ops + * provides handlers for slave device register/unregister/link change/ + * name change events. + * + * Return: pointer to failover instance + */ +struct failover *failover_register(struct net_device *dev, + struct failover_ops *ops) +{ + struct failover *failover; + + if (dev->type != ARPHRD_ETHER) + return ERR_PTR(-EINVAL); + + failover = kzalloc(sizeof(*failover), GFP_KERNEL); + if (!failover) + return ERR_PTR(-ENOMEM); + + rcu_assign_pointer(failover->ops, ops); + dev_hold(dev); + dev->priv_flags |= IFF_FAILOVER; + rcu_assign_pointer(failover->failover_dev, dev); + + spin_lock(&failover_lock); + list_add_tail(&failover->list, &failover_list); + spin_unlock(&failover_lock); + + netdev_info(dev, "failover master:%s registered\n", dev->name); + + failover_existing_slave_register(dev); + + return failover; +} +EXPORT_SYMBOL_GPL(failover_register); + +/** + * failover_unregister - Unregister a failover instance + * + * @failover: pointer to failover instance + * + * Unregisters and frees a failover instance. + */ +void failover_unregister(struct failover *failover) +{ + struct net_device *failover_dev; + + failover_dev = rcu_dereference(failover->failover_dev); + + netdev_info(failover_dev, "failover master:%s unregistered\n", + failover_dev->name); + + failover_dev->priv_flags &= ~IFF_FAILOVER; + dev_put(failover_dev); + + spin_lock(&failover_lock); + list_del(&failover->list); + spin_unlock(&failover_lock); + + kfree(failover); +} +EXPORT_SYMBOL_GPL(failover_unregister); + +static __init int +failover_init(void) +{ + register_netdevice_notifier(&failover_notifier); + + return 0; +} +module_init(failover_init); + +static __exit +void failover_exit(void) +{ + unregister_netdevice_notifier(&failover_notifier); +} +module_exit(failover_exit); + +MODULE_DESCRIPTION("Generic failover infrastructure/interface"); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3-59-g8ed1b