| Message ID | 1524188524-28411-3-git-send-email-sridhar.samudrala@intel.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | Enable virtio_net to act as a standby for a passthru device | expand |
On Thu, Apr 19, 2018 at 06:42:02PM -0700, Sridhar Samudrala wrote: > This provides a generic interface for paravirtual drivers to listen > for netdev register/unregister/link change events from pci ethernet > devices with the same MAC and takeover their datapath. The notifier and > event handling code is based on the existing netvsc implementation. > > It exposes 2 sets of interfaces to the paravirtual drivers. > 1. existing netvsc driver that uses 2 netdev model. In this model, no > master netdev is created. The paravirtual driver registers each instance > of netvsc as a 'failover' instance along with a set of ops to manage the > slave events. > failover_register() > failover_unregister() > 2. new virtio_net based solution that uses 3 netdev model. In this model, > the failover module provides interfaces to create/destroy additional master > netdev and all the slave events are managed internally. > failover_create() > failover_destroy() > These functions call failover_register()/failover_unregister() with the > master netdev created by the failover module. > > Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> I like this patch. Yes something to improve (see below) > --- > include/linux/netdevice.h | 16 + > include/net/failover.h | 96 ++++++ > net/Kconfig | 18 + > net/core/Makefile | 1 + > net/core/failover.c | 844 ++++++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 975 insertions(+) > create mode 100644 include/net/failover.h > create mode 100644 net/core/failover.c > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index cf44503ea81a..ed535b6724e1 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1401,6 +1401,8 @@ 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, > @@ -1430,6 +1432,8 @@ 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 > @@ -1458,6 +1462,8 @@ 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. > @@ -4308,6 +4314,16 @@ 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) > { > diff --git a/include/net/failover.h b/include/net/failover.h > new file mode 100644 > index 000000000000..0b8601043d90 > --- /dev/null > +++ b/include/net/failover.h > @@ -0,0 +1,96 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* Copyright (c) 2018, Intel Corporation. */ > + > +#ifndef _NET_FAILOVER_H > +#define _NET_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_join)(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_release)(struct net_device *slave_dev, > + struct net_device *failover_dev); > + int (*slave_link_change)(struct net_device *slave_dev, > + struct net_device *failover_dev); > + rx_handler_result_t (*handle_frame)(struct sk_buff **pskb); > +}; > + > +struct failover { > + struct list_head list; > + struct net_device __rcu *failover_dev; > + struct failover_ops __rcu *ops; > +}; > + > +/* failover state */ > +struct failover_info { > + /* primary netdev with same MAC */ > + struct net_device __rcu *primary_dev; > + > + /* standby netdev */ > + struct net_device __rcu *standby_dev; > + > + /* primary netdev stats */ > + struct rtnl_link_stats64 primary_stats; > + > + /* standby netdev stats */ > + struct rtnl_link_stats64 standby_stats; > + > + /* aggregated stats */ > + struct rtnl_link_stats64 failover_stats; > + > + /* spinlock while updating stats */ > + spinlock_t stats_lock; > +}; > + > +#if IS_ENABLED(CONFIG_NET_FAILOVER) > + > +int failover_create(struct net_device *standby_dev, > + struct failover **pfailover); > +void failover_destroy(struct failover *failover); > + > +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, > + struct failover **pfailover); > +void failover_unregister(struct failover *failover); > + > +int failover_slave_unregister(struct net_device *slave_dev); > + > +#else > + > +static inline > +int failover_create(struct net_device *standby_dev, > + struct failover **pfailover); > +{ > + return 0; > +} > + > +static inline > +void failover_destroy(struct failover *failover) > +{ > +} > + > +static inline > +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, > + struct pfailover **pfailover); > +{ > + return 0; > +} > + > +static inline > +void failover_unregister(struct failover *failover) > +{ > +} > + > +static inline > +int failover_slave_unregister(struct net_device *slave_dev) > +{ > + return 0; > +} > + > +#endif > + > +#endif /* _NET_FAILOVER_H */ > diff --git a/net/Kconfig b/net/Kconfig > index 0428f12c25c2..388b99dfee10 100644 > --- a/net/Kconfig > +++ b/net/Kconfig > @@ -423,6 +423,24 @@ config MAY_USE_DEVLINK > on MAY_USE_DEVLINK to ensure they do not cause link errors when > devlink is a loadable module and the driver using it is built-in. > > +config NET_FAILOVER > + tristate "Failover interface" > + help > + This provides a generic interface for paravirtual drivers to listen > + for netdev register/unregister/link change events from pci ethernet > + devices with the same MAC and takeover their datapath. This also > + enables live migration of a VM with direct attached VF by failing > + over to the paravirtual datapath when the VF is unplugged. > + > +config MAY_USE_FAILOVER > + tristate > + default m if NET_FAILOVER=m > + default y if NET_FAILOVER=y || NET_FAILOVER=n > + help > + Drivers using the failover infrastructure should have a dependency > + on MAY_USE_FAILOVER to ensure they do not cause link errors when > + failover is a loadable module and the driver using it is built-in. > + > 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 6dbbba8c57ae..cef17518bb7d 100644 > --- a/net/core/Makefile > +++ b/net/core/Makefile > @@ -30,3 +30,4 @@ 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_NET_FAILOVER) += failover.o > diff --git a/net/core/failover.c b/net/core/failover.c > new file mode 100644 > index 000000000000..7bee762cb737 > --- /dev/null > +++ b/net/core/failover.c > @@ -0,0 +1,844 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2018, Intel Corporation. */ I think you should copy the header from bond_main.c upon which some of the code seems to be based. > + > +/* 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 <linux/netdevice.h> > +#include <linux/etherdevice.h> > +#include <linux/ethtool.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/netdevice.h> > +#include <linux/netpoll.h> > +#include <linux/rtnetlink.h> > +#include <linux/if_vlan.h> > +#include <linux/pci.h> > +#include <net/sch_generic.h> > +#include <uapi/linux/if_arp.h> > +#include <net/failover.h> > + > +static LIST_HEAD(failover_list); > +static DEFINE_SPINLOCK(failover_lock); > + > +static int failover_slave_pre_register(struct net_device *slave_dev, > + struct net_device *failover_dev, > + struct failover_ops *failover_ops) > +{ > + struct failover_info *finfo; > + bool standby; > + > + if (failover_ops) { > + if (!failover_ops->slave_pre_register) > + return -EINVAL; > + > + return failover_ops->slave_pre_register(slave_dev, > + failover_dev); > + } > + > + finfo = netdev_priv(failover_dev); > + standby = (slave_dev->dev.parent == failover_dev->dev.parent); > + if (standby ? rtnl_dereference(finfo->standby_dev) : > + rtnl_dereference(finfo->primary_dev)) { > + netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n", > + slave_dev->name, standby ? "standby" : "primary"); > + return -EEXIST; > + } > + > + /* Avoid non pci devices as primary netdev */ Why? Pls change this comment so it explains the motivation rather than just repeat what the code does. > + if (!standby && (!slave_dev->dev.parent || > + !dev_is_pci(slave_dev->dev.parent))) > + return -EINVAL; > + > + return 0; > +} > + > +static int failover_slave_join(struct net_device *slave_dev, > + struct net_device *failover_dev, > + struct failover_ops *failover_ops) > +{ > + struct failover_info *finfo; > + int err, orig_mtu; > + bool standby; > + > + if (failover_ops) { > + if (!failover_ops->slave_join) > + return -EINVAL; > + > + return failover_ops->slave_join(slave_dev, failover_dev); > + } > + > + if (netif_running(failover_dev)) { > + err = dev_open(slave_dev); > + if (err && (err != -EBUSY)) { > + netdev_err(failover_dev, "Opening slave %s failed err:%d\n", > + slave_dev->name, err); > + goto err_dev_open; > + } > + } > + > + /* Align MTU of slave with failover dev */ > + orig_mtu = slave_dev->mtu; I suspect this was copied from bond. this variable is never used and I'm even surprised gcc did not warn about this. > + err = dev_set_mtu(slave_dev, failover_dev->mtu); How do we know slave supports this MTU? same applies to failover_change_mtu. > + if (err) { > + netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n", > + slave_dev->name, failover_dev->mtu); > + goto err_set_mtu; > + } > + > + finfo = netdev_priv(failover_dev); > + standby = (slave_dev->dev.parent == failover_dev->dev.parent); > + > + dev_hold(slave_dev); > + > + if (standby) { > + rcu_assign_pointer(finfo->standby_dev, slave_dev); > + dev_get_stats(finfo->standby_dev, &finfo->standby_stats); > + } else { > + rcu_assign_pointer(finfo->primary_dev, slave_dev); > + dev_get_stats(finfo->primary_dev, &finfo->primary_stats); > + failover_dev->min_mtu = slave_dev->min_mtu; > + failover_dev->max_mtu = slave_dev->max_mtu; > + } > + > + netdev_info(failover_dev, "failover slave:%s joined\n", > + slave_dev->name); > + > + return 0; > + > +err_set_mtu: > + dev_close(slave_dev); > +err_dev_open: > + return err; > +} > + > +/* Called when slave dev is injecting data into network stack. > + * Change the associated network device from lower dev to virtio. > + * note: already called with rcu_read_lock > + */ > +static rx_handler_result_t failover_handle_frame(struct sk_buff **pskb) > +{ > + struct sk_buff *skb = *pskb; > + struct net_device *ndev = rcu_dereference(skb->dev->rx_handler_data); > + > + skb->dev = ndev; > + > + return RX_HANDLER_ANOTHER; > +} > + > +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; > +} > + > +static int failover_slave_register(struct net_device *slave_dev) > +{ > + struct failover_ops *failover_ops; > + struct net_device *failover_dev; > + int ret; > + > + ASSERT_RTNL(); > + > + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); > + if (!failover_dev) > + goto done; > + > + ret = failover_slave_pre_register(slave_dev, failover_dev, > + failover_ops); > + if (ret) > + goto done; > + > + ret = netdev_rx_handler_register(slave_dev, failover_ops ? > + failover_ops->handle_frame : > + failover_handle_frame, failover_dev); > + if (ret) { > + netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n", > + ret); > + goto done; > + } > + > + ret = netdev_upper_dev_link(slave_dev, failover_dev, NULL); > + if (ret) { > + netdev_err(slave_dev, "can not set failover device %s (err = %d)\n", > + failover_dev->name, ret); > + goto upper_link_failed; > + } > + > + slave_dev->priv_flags |= IFF_FAILOVER_SLAVE; > + > + ret = failover_slave_join(slave_dev, failover_dev, failover_ops); > + if (ret) > + goto err_join; > + > + call_netdevice_notifiers(NETDEV_JOIN, slave_dev); > + > + netdev_info(failover_dev, "failover slave:%s registered\n", > + slave_dev->name); > + > + goto done; > + > +err_join: > + netdev_upper_dev_unlink(slave_dev, failover_dev); > + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; > +upper_link_failed: > + netdev_rx_handler_unregister(slave_dev); > +done: > + return NOTIFY_DONE; > +} > + > +static int failover_slave_pre_unregister(struct net_device *slave_dev, > + struct net_device *failover_dev, > + struct failover_ops *failover_ops) > +{ > + struct net_device *standby_dev, *primary_dev; > + struct failover_info *finfo; > + > + if (failover_ops) { > + if (!failover_ops->slave_pre_unregister) > + return -EINVAL; > + > + return failover_ops->slave_pre_unregister(slave_dev, > + failover_dev); > + } > + > + finfo = netdev_priv(failover_dev); > + primary_dev = rtnl_dereference(finfo->primary_dev); > + standby_dev = rtnl_dereference(finfo->standby_dev); > + > + if (slave_dev != primary_dev && slave_dev != standby_dev) > + return -EINVAL; > + > + return 0; > +} > + > +static int failover_slave_release(struct net_device *slave_dev, > + struct net_device *failover_dev, > + struct failover_ops *failover_ops) > +{ > + struct net_device *standby_dev, *primary_dev; > + struct failover_info *finfo; > + > + if (failover_ops) { > + if (!failover_ops->slave_release) > + return -EINVAL; > + > + return failover_ops->slave_release(slave_dev, failover_dev); > + } > + > + finfo = netdev_priv(failover_dev); > + primary_dev = rtnl_dereference(finfo->primary_dev); > + standby_dev = rtnl_dereference(finfo->standby_dev); > + > + if (slave_dev == standby_dev) { > + RCU_INIT_POINTER(finfo->standby_dev, NULL); > + } else { > + RCU_INIT_POINTER(finfo->primary_dev, NULL); > + if (standby_dev) { > + failover_dev->min_mtu = standby_dev->min_mtu; > + failover_dev->max_mtu = standby_dev->max_mtu; > + } > + } > + > + dev_put(slave_dev); > + > + netdev_info(failover_dev, "failover slave:%s released\n", > + slave_dev->name); > + > + return 0; > +} > + > +int failover_slave_unregister(struct net_device *slave_dev) > +{ > + struct failover_ops *failover_ops; > + struct net_device *failover_dev; > + int ret; > + > + if (!netif_is_failover_slave(slave_dev)) > + goto done; > + > + ASSERT_RTNL(); > + > + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); > + if (!failover_dev) > + goto done; > + > + ret = failover_slave_pre_unregister(slave_dev, failover_dev, > + failover_ops); > + if (ret) > + goto done; > + > + netdev_rx_handler_unregister(slave_dev); > + netdev_upper_dev_unlink(slave_dev, failover_dev); > + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; > + > + failover_slave_release(slave_dev, failover_dev, failover_ops); Don't you need to get stats from it? This device is going away ... > + > + netdev_info(failover_dev, "failover slave:%s unregistered\n", > + slave_dev->name); > + > +done: > + return NOTIFY_DONE; > +} > +EXPORT_SYMBOL_GPL(failover_slave_unregister); > + > +static bool failover_xmit_ready(struct net_device *dev) > +{ > + return netif_running(dev) && netif_carrier_ok(dev); > +} > + > +static int failover_slave_link_change(struct net_device *slave_dev) > +{ > + struct net_device *failover_dev, *primary_dev, *standby_dev; > + struct failover_ops *failover_ops; > + struct failover_info *finfo; > + > + if (!netif_is_failover_slave(slave_dev)) > + goto done; > + > + ASSERT_RTNL(); > + > + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); > + if (!failover_dev) > + goto done; > + > + if (failover_ops) { > + if (!failover_ops->slave_link_change) > + goto done; > + > + return failover_ops->slave_link_change(slave_dev, failover_dev); > + } > + > + if (!netif_running(failover_dev)) > + return 0; > + > + finfo = netdev_priv(failover_dev); > + > + primary_dev = rtnl_dereference(finfo->primary_dev); > + standby_dev = rtnl_dereference(finfo->standby_dev); > + > + if (slave_dev != primary_dev && slave_dev != standby_dev) > + goto done; > + > + if ((primary_dev && failover_xmit_ready(primary_dev)) || > + (standby_dev && failover_xmit_ready(standby_dev))) { > + netif_carrier_on(failover_dev); > + netif_tx_wake_all_queues(failover_dev); > + } else { > + netif_carrier_off(failover_dev); > + netif_tx_stop_all_queues(failover_dev); And I think it's a good idea to get stats from device here too. > + } > + > +done: > + return NOTIFY_DONE; > +} > + > +static bool failover_validate_event_dev(struct net_device *dev) > +{ > + /* Skip parent events */ > + if (netif_is_failover(dev)) > + return false; > + > + /* Avoid non-Ethernet type devices */ ... for now. It would be possible easy to make this generic - just copy things like type and addr_len from slave. > + if (dev->type != ARPHRD_ETHER) > + return false; > + > + return true; > +} > + > +static int > +failover_event(struct notifier_block *this, unsigned long event, void *ptr) > +{ > + struct net_device *event_dev = netdev_notifier_info_to_dev(ptr); > + > + if (!failover_validate_event_dev(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); > + default: > + return NOTIFY_DONE; > + } > +} > + > +static struct notifier_block failover_notifier = { > + .notifier_call = failover_event, > +}; > + > +static int failover_open(struct net_device *dev) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *primary_dev, *standby_dev; > + int err; > + > + netif_carrier_off(dev); > + netif_tx_wake_all_queues(dev); > + > + primary_dev = rtnl_dereference(finfo->primary_dev); > + if (primary_dev) { > + err = dev_open(primary_dev); > + if (err) > + goto err_primary_open; > + } > + > + standby_dev = rtnl_dereference(finfo->standby_dev); > + if (standby_dev) { > + err = dev_open(standby_dev); > + if (err) > + goto err_standby_open; > + } > + > + return 0; > + > +err_standby_open: > + dev_close(primary_dev); > +err_primary_open: > + netif_tx_disable(dev); > + return err; > +} > + > +static int failover_close(struct net_device *dev) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *slave_dev; > + > + netif_tx_disable(dev); > + > + slave_dev = rtnl_dereference(finfo->primary_dev); > + if (slave_dev) > + dev_close(slave_dev); > + > + slave_dev = rtnl_dereference(finfo->standby_dev); > + if (slave_dev) > + dev_close(slave_dev); > + > + return 0; > +} > + > +static netdev_tx_t failover_drop_xmit(struct sk_buff *skb, > + struct net_device *dev) > +{ > + atomic_long_inc(&dev->tx_dropped); > + dev_kfree_skb_any(skb); > + return NETDEV_TX_OK; > +} > + > +static netdev_tx_t failover_start_xmit(struct sk_buff *skb, > + struct net_device *dev) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *xmit_dev; > + > + /* Try xmit via primary netdev followed by standby netdev */ > + xmit_dev = rcu_dereference_bh(finfo->primary_dev); > + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) { > + xmit_dev = rcu_dereference_bh(finfo->standby_dev); > + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) > + return failover_drop_xmit(skb, dev); > + } > + > + skb->dev = xmit_dev; > + skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping; > + > + return dev_queue_xmit(skb); > +} Is this going through qdisc twice? Won't this hurt performance measureably? > + > +static u16 failover_select_queue(struct net_device *dev, struct sk_buff *skb, > + void *accel_priv, > + select_queue_fallback_t fallback) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *primary_dev; > + u16 txq; > + > + rcu_read_lock(); > + primary_dev = rcu_dereference(finfo->primary_dev); > + if (primary_dev) { > + const struct net_device_ops *ops = primary_dev->netdev_ops; > + > + if (ops->ndo_select_queue) > + txq = ops->ndo_select_queue(primary_dev, skb, > + accel_priv, fallback); > + else > + txq = fallback(primary_dev, skb); > + > + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; > + > + return txq; > + } > + > + txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0; > + > + /* Save the original txq to restore before passing to the driver */ > + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; > + > + if (unlikely(txq >= dev->real_num_tx_queues)) { > + do { > + txq -= dev->real_num_tx_queues; > + } while (txq >= dev->real_num_tx_queues); > + } > + > + return txq; > +} > + > +/* fold stats, assuming all rtnl_link_stats64 fields are u64, but > + * that some drivers can provide 32finfot values only. > + */ > +static void failover_fold_stats(struct rtnl_link_stats64 *_res, > + const struct rtnl_link_stats64 *_new, > + const struct rtnl_link_stats64 *_old) > +{ > + const u64 *new = (const u64 *)_new; > + const u64 *old = (const u64 *)_old; > + u64 *res = (u64 *)_res; > + int i; > + > + for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) { > + u64 nv = new[i]; > + u64 ov = old[i]; > + s64 delta = nv - ov; > + > + /* detects if this particular field is 32bit only */ > + if (((nv | ov) >> 32) == 0) > + delta = (s64)(s32)((u32)nv - (u32)ov); > + > + /* filter anomalies, some drivers reset their stats > + * at down/up events. > + */ > + if (delta > 0) > + res[i] += delta; > + } > +} > + > +static void failover_get_stats(struct net_device *dev, > + struct rtnl_link_stats64 *stats) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + const struct rtnl_link_stats64 *new; > + struct rtnl_link_stats64 temp; > + struct net_device *slave_dev; > + > + spin_lock(&finfo->stats_lock); > + memcpy(stats, &finfo->failover_stats, sizeof(*stats)); > + > + rcu_read_lock(); > + > + slave_dev = rcu_dereference(finfo->primary_dev); > + if (slave_dev) { > + new = dev_get_stats(slave_dev, &temp); > + failover_fold_stats(stats, new, &finfo->primary_stats); > + memcpy(&finfo->primary_stats, new, sizeof(*new)); > + } > + > + slave_dev = rcu_dereference(finfo->standby_dev); > + if (slave_dev) { > + new = dev_get_stats(slave_dev, &temp); > + failover_fold_stats(stats, new, &finfo->standby_stats); > + memcpy(&finfo->standby_stats, new, sizeof(*new)); > + } > + > + rcu_read_unlock(); > + > + memcpy(&finfo->failover_stats, stats, sizeof(*stats)); > + spin_unlock(&finfo->stats_lock); > +} > + > +static int failover_change_mtu(struct net_device *dev, int new_mtu) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *primary_dev, *standby_dev; > + int ret = 0; > + > + primary_dev = rcu_dereference(finfo->primary_dev); > + if (primary_dev) { > + ret = dev_set_mtu(primary_dev, new_mtu); > + if (ret) > + return ret; > + } > + > + standby_dev = rcu_dereference(finfo->standby_dev); > + if (standby_dev) { > + ret = dev_set_mtu(standby_dev, new_mtu); > + if (ret) { > + dev_set_mtu(primary_dev, dev->mtu); > + return ret; > + } > + } > + > + dev->mtu = new_mtu; > + return 0; > +} > + > +static void failover_set_rx_mode(struct net_device *dev) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *slave_dev; > + > + rcu_read_lock(); > + > + slave_dev = rcu_dereference(finfo->primary_dev); > + if (slave_dev) { > + dev_uc_sync_multiple(slave_dev, dev); > + dev_mc_sync_multiple(slave_dev, dev); > + } > + > + slave_dev = rcu_dereference(finfo->standby_dev); > + if (slave_dev) { > + dev_uc_sync_multiple(slave_dev, dev); > + dev_mc_sync_multiple(slave_dev, dev); > + } > + > + rcu_read_unlock(); > +} > + > +static const struct net_device_ops failover_dev_ops = { > + .ndo_open = failover_open, > + .ndo_stop = failover_close, > + .ndo_start_xmit = failover_start_xmit, > + .ndo_select_queue = failover_select_queue, > + .ndo_get_stats64 = failover_get_stats, > + .ndo_change_mtu = failover_change_mtu, > + .ndo_set_rx_mode = failover_set_rx_mode, > + .ndo_validate_addr = eth_validate_addr, > + .ndo_features_check = passthru_features_check, xdp support? > +}; > + > +#define FAILOVER_NAME "failover" > +#define FAILOVER_VERSION "0.1" > + > +static void failover_ethtool_get_drvinfo(struct net_device *dev, > + struct ethtool_drvinfo *drvinfo) > +{ > + strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver)); > + strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version)); > +} > + > +int failover_ethtool_get_link_ksettings(struct net_device *dev, > + struct ethtool_link_ksettings *cmd) > +{ > + struct failover_info *finfo = netdev_priv(dev); > + struct net_device *slave_dev; > + > + slave_dev = rtnl_dereference(finfo->primary_dev); > + if (!slave_dev || !failover_xmit_ready(slave_dev)) { > + slave_dev = rtnl_dereference(finfo->standby_dev); > + if (!slave_dev || !failover_xmit_ready(slave_dev)) { > + cmd->base.duplex = DUPLEX_UNKNOWN; > + cmd->base.port = PORT_OTHER; > + cmd->base.speed = SPEED_UNKNOWN; > + > + return 0; > + } > + } > + > + return __ethtool_get_link_ksettings(slave_dev, cmd); > +} > +EXPORT_SYMBOL_GPL(failover_ethtool_get_link_ksettings); > + > +static const struct ethtool_ops failover_ethtool_ops = { > + .get_drvinfo = failover_ethtool_get_drvinfo, > + .get_link = ethtool_op_get_link, > + .get_link_ksettings = failover_ethtool_get_link_ksettings, > +}; > + > +static void failover_register_existing_slave(struct net_device *failover_dev) > +{ > + struct net *net = dev_net(failover_dev); > + struct net_device *dev; > + > + rtnl_lock(); > + for_each_netdev(net, dev) { > + if (dev == failover_dev) > + continue; > + if (!failover_validate_event_dev(dev)) > + continue; > + if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr)) > + failover_slave_register(dev); > + } > + rtnl_unlock(); > +} > + > +int failover_register(struct net_device *dev, struct failover_ops *ops, > + struct failover **pfailover) > +{ > + struct failover *failover; > + > + failover = kzalloc(sizeof(*failover), GFP_KERNEL); > + if (!failover) > + return -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); > + > + failover_register_existing_slave(dev); > + > + *pfailover = failover; > + return 0; > +} > +EXPORT_SYMBOL_GPL(failover_register); > + > +void failover_unregister(struct failover *failover) > +{ > + struct net_device *failover_dev; > + > + failover_dev = rcu_dereference(failover->failover_dev); > + > + 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); > + > +int failover_create(struct net_device *standby_dev, struct failover **pfailover) > +{ > + struct device *dev = standby_dev->dev.parent; > + struct net_device *failover_dev; > + int err; > + > + /* Alloc at least 2 queues, for now we are going with 16 assuming > + * that most devices being bonded won't have too many queues. > + */ > + failover_dev = alloc_etherdev_mq(sizeof(struct failover_info), 16); > + if (!failover_dev) { > + dev_err(dev, "Unable to allocate failover_netdev!\n"); > + return -ENOMEM; > + } > + > + dev_net_set(failover_dev, dev_net(standby_dev)); > + SET_NETDEV_DEV(failover_dev, dev); > + > + failover_dev->netdev_ops = &failover_dev_ops; > + failover_dev->ethtool_ops = &failover_ethtool_ops; > + > + /* Initialize the device options */ > + failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE; > + failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | > + IFF_TX_SKB_SHARING); > + > + /* don't acquire failover netdev's netif_tx_lock when transmitting */ > + failover_dev->features |= NETIF_F_LLTX; > + > + /* Don't allow failover devices to change network namespaces. */ > + failover_dev->features |= NETIF_F_NETNS_LOCAL; > + > + failover_dev->hw_features = NETIF_F_HW_CSUM | NETIF_F_SG | > + NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | > + NETIF_F_HIGHDMA | NETIF_F_LRO; OK but then you must make sure your primary and standby both support these features. > + > + failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL; > + failover_dev->features |= failover_dev->hw_features; > + > + memcpy(failover_dev->dev_addr, standby_dev->dev_addr, > + failover_dev->addr_len); > + > + failover_dev->min_mtu = standby_dev->min_mtu; > + failover_dev->max_mtu = standby_dev->max_mtu; OK MTU is copied, fine. But is this always enough? How about e.g. hard_header_len? min_header_len? needed_headroom? needed_tailroom? I'd worry that even if you cover existing ones more might be added with time. A function copying config between devices probably belongs in some central place IMHO. > + > + err = register_netdev(failover_dev); > + if (err < 0) { > + dev_err(dev, "Unable to register failover_dev!\n"); > + goto err_register_netdev; > + } > + > + netif_carrier_off(failover_dev); > + > + err = failover_register(failover_dev, NULL, pfailover); > + if (err < 0) > + goto err_failover; > + > + return 0; > + > +err_failover: > + unregister_netdev(failover_dev); > +err_register_netdev: > + free_netdev(failover_dev); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(failover_create); > + > +void failover_destroy(struct failover *failover) > +{ > + struct net_device *failover_dev; > + struct net_device *slave_dev; > + struct failover_info *finfo; > + > + if (!failover) > + return; > + > + failover_dev = rcu_dereference(failover->failover_dev); > + finfo = netdev_priv(failover_dev); > + > + netif_device_detach(failover_dev); > + > + rtnl_lock(); > + > + slave_dev = rtnl_dereference(finfo->primary_dev); > + if (slave_dev) > + failover_slave_unregister(slave_dev); > + > + slave_dev = rtnl_dereference(finfo->standby_dev); > + if (slave_dev) > + failover_slave_unregister(slave_dev); > + > + failover_unregister(failover); > + > + unregister_netdevice(failover_dev); > + > + rtnl_unlock(); > + > + free_netdev(failover_dev); > +} > +EXPORT_SYMBOL_GPL(failover_destroy); > + > +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("Failover infrastructure/interface for Paravirtual drivers"); > +MODULE_LICENSE("GPL v2"); > -- > 2.14.3
On Thu, Apr 19, 2018 at 06:42:02PM -0700, Sridhar Samudrala wrote: > +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; > +} So it bothers me that this ties to just any device at all. I thought hard about it, and I see a nice solution. Here goes: QEMU has a pci-bridge-seat device. It is used currently to group e.g. input devices for multiseat support. Now if you squint at it hard enough, you can see we are also in a grouping problem. So how about the following: 1. allocate a virtio pci bridge device failover grouping id (reserve through virtio TC). 2. only group two devices in a failover configuration if both are under the same bridge with this id (in addition to a mac check). In particular a bridged configuration makes it easier to make sure the standby is enumerated before the primary. In fact we could fail init of failover if we see appear standby *after* primary. And this allows many devices with the same ethernet address without any issues - just under separate bridges. Further if we ever want to enumerate in parallel this can be supported by adding a driver for the bridge. In fact, I see how down the road such a device could be the beginning of the more ambitious plan to expose a powerful switchdev interface for more advanced So far so good, but I see a couple of issues: - it is PCI specific Not a big deal: we limit ourselves to PCI anyway ATM. - does not work across PCI domains - which are helpful for NUMA (e.g. we want to be able to move to primary which is on a different numa node without losing connectivity). Idea: add a "group ID" register to each of these pci bridge devices (e.g. in device specific config space). Match two bridges if they have the same group ID. - all these extra bridges slow enumeration down somewhat Idea: as a fallback if no bridge is found, just assume all devices match, which will result in falling back on the "match by mac" logic like in this patchset. Will be fine for simple setups. Thoughts?
On 4/19/2018 7:44 PM, Michael S. Tsirkin wrote: > On Thu, Apr 19, 2018 at 06:42:02PM -0700, Sridhar Samudrala wrote: >> This provides a generic interface for paravirtual drivers to listen >> for netdev register/unregister/link change events from pci ethernet >> devices with the same MAC and takeover their datapath. The notifier and >> event handling code is based on the existing netvsc implementation. >> >> It exposes 2 sets of interfaces to the paravirtual drivers. >> 1. existing netvsc driver that uses 2 netdev model. In this model, no >> master netdev is created. The paravirtual driver registers each instance >> of netvsc as a 'failover' instance along with a set of ops to manage the >> slave events. >> failover_register() >> failover_unregister() >> 2. new virtio_net based solution that uses 3 netdev model. In this model, >> the failover module provides interfaces to create/destroy additional master >> netdev and all the slave events are managed internally. >> failover_create() >> failover_destroy() >> These functions call failover_register()/failover_unregister() with the >> master netdev created by the failover module. >> >> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> > I like this patch. Yes something to improve (see below) > >> --- >> include/linux/netdevice.h | 16 + >> include/net/failover.h | 96 ++++++ >> net/Kconfig | 18 + >> net/core/Makefile | 1 + >> net/core/failover.c | 844 ++++++++++++++++++++++++++++++++++++++++++++++ >> 5 files changed, 975 insertions(+) >> create mode 100644 include/net/failover.h >> create mode 100644 net/core/failover.c >> >> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h >> index cf44503ea81a..ed535b6724e1 100644 >> --- a/include/linux/netdevice.h >> +++ b/include/linux/netdevice.h >> @@ -1401,6 +1401,8 @@ 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, >> @@ -1430,6 +1432,8 @@ 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 >> @@ -1458,6 +1462,8 @@ 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. >> @@ -4308,6 +4314,16 @@ 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) >> { >> diff --git a/include/net/failover.h b/include/net/failover.h >> new file mode 100644 >> index 000000000000..0b8601043d90 >> --- /dev/null >> +++ b/include/net/failover.h >> @@ -0,0 +1,96 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* Copyright (c) 2018, Intel Corporation. */ >> + >> +#ifndef _NET_FAILOVER_H >> +#define _NET_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_join)(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_release)(struct net_device *slave_dev, >> + struct net_device *failover_dev); >> + int (*slave_link_change)(struct net_device *slave_dev, >> + struct net_device *failover_dev); >> + rx_handler_result_t (*handle_frame)(struct sk_buff **pskb); >> +}; >> + >> +struct failover { >> + struct list_head list; >> + struct net_device __rcu *failover_dev; >> + struct failover_ops __rcu *ops; >> +}; >> + >> +/* failover state */ >> +struct failover_info { >> + /* primary netdev with same MAC */ >> + struct net_device __rcu *primary_dev; >> + >> + /* standby netdev */ >> + struct net_device __rcu *standby_dev; >> + >> + /* primary netdev stats */ >> + struct rtnl_link_stats64 primary_stats; >> + >> + /* standby netdev stats */ >> + struct rtnl_link_stats64 standby_stats; >> + >> + /* aggregated stats */ >> + struct rtnl_link_stats64 failover_stats; >> + >> + /* spinlock while updating stats */ >> + spinlock_t stats_lock; >> +}; >> + >> +#if IS_ENABLED(CONFIG_NET_FAILOVER) >> + >> +int failover_create(struct net_device *standby_dev, >> + struct failover **pfailover); >> +void failover_destroy(struct failover *failover); >> + >> +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, >> + struct failover **pfailover); >> +void failover_unregister(struct failover *failover); >> + >> +int failover_slave_unregister(struct net_device *slave_dev); >> + >> +#else >> + >> +static inline >> +int failover_create(struct net_device *standby_dev, >> + struct failover **pfailover); >> +{ >> + return 0; >> +} >> + >> +static inline >> +void failover_destroy(struct failover *failover) >> +{ >> +} >> + >> +static inline >> +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, >> + struct pfailover **pfailover); >> +{ >> + return 0; >> +} >> + >> +static inline >> +void failover_unregister(struct failover *failover) >> +{ >> +} >> + >> +static inline >> +int failover_slave_unregister(struct net_device *slave_dev) >> +{ >> + return 0; >> +} >> + >> +#endif >> + >> +#endif /* _NET_FAILOVER_H */ >> diff --git a/net/Kconfig b/net/Kconfig >> index 0428f12c25c2..388b99dfee10 100644 >> --- a/net/Kconfig >> +++ b/net/Kconfig >> @@ -423,6 +423,24 @@ config MAY_USE_DEVLINK >> on MAY_USE_DEVLINK to ensure they do not cause link errors when >> devlink is a loadable module and the driver using it is built-in. >> >> +config NET_FAILOVER >> + tristate "Failover interface" >> + help >> + This provides a generic interface for paravirtual drivers to listen >> + for netdev register/unregister/link change events from pci ethernet >> + devices with the same MAC and takeover their datapath. This also >> + enables live migration of a VM with direct attached VF by failing >> + over to the paravirtual datapath when the VF is unplugged. >> + >> +config MAY_USE_FAILOVER >> + tristate >> + default m if NET_FAILOVER=m >> + default y if NET_FAILOVER=y || NET_FAILOVER=n >> + help >> + Drivers using the failover infrastructure should have a dependency >> + on MAY_USE_FAILOVER to ensure they do not cause link errors when >> + failover is a loadable module and the driver using it is built-in. >> + >> 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 6dbbba8c57ae..cef17518bb7d 100644 >> --- a/net/core/Makefile >> +++ b/net/core/Makefile >> @@ -30,3 +30,4 @@ 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_NET_FAILOVER) += failover.o >> diff --git a/net/core/failover.c b/net/core/failover.c >> new file mode 100644 >> index 000000000000..7bee762cb737 >> --- /dev/null >> +++ b/net/core/failover.c >> @@ -0,0 +1,844 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* Copyright (c) 2018, Intel Corporation. */ > > I think you should copy the header from bond_main.c upon which > some of the code seems to be based. Yes. some of the code is based on bonding/team and netvsc. i added a reference to netvsc in the comment, will also include bonding/team driver. > >> + >> +/* 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 <linux/netdevice.h> >> +#include <linux/etherdevice.h> >> +#include <linux/ethtool.h> >> +#include <linux/module.h> >> +#include <linux/slab.h> >> +#include <linux/netdevice.h> >> +#include <linux/netpoll.h> >> +#include <linux/rtnetlink.h> >> +#include <linux/if_vlan.h> >> +#include <linux/pci.h> >> +#include <net/sch_generic.h> >> +#include <uapi/linux/if_arp.h> >> +#include <net/failover.h> >> + >> +static LIST_HEAD(failover_list); >> +static DEFINE_SPINLOCK(failover_lock); >> + >> +static int failover_slave_pre_register(struct net_device *slave_dev, >> + struct net_device *failover_dev, >> + struct failover_ops *failover_ops) >> +{ >> + struct failover_info *finfo; >> + bool standby; >> + >> + if (failover_ops) { >> + if (!failover_ops->slave_pre_register) >> + return -EINVAL; >> + >> + return failover_ops->slave_pre_register(slave_dev, >> + failover_dev); >> + } >> + >> + finfo = netdev_priv(failover_dev); >> + standby = (slave_dev->dev.parent == failover_dev->dev.parent); >> + if (standby ? rtnl_dereference(finfo->standby_dev) : >> + rtnl_dereference(finfo->primary_dev)) { >> + netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n", >> + slave_dev->name, standby ? "standby" : "primary"); >> + return -EEXIST; >> + } >> + >> + /* Avoid non pci devices as primary netdev */ > Why? Pls change this comment so it explains the motivation > rather than just repeat what the code does. OK. > >> + if (!standby && (!slave_dev->dev.parent || >> + !dev_is_pci(slave_dev->dev.parent))) >> + return -EINVAL; >> + >> + return 0; >> +} >> + >> +static int failover_slave_join(struct net_device *slave_dev, >> + struct net_device *failover_dev, >> + struct failover_ops *failover_ops) >> +{ >> + struct failover_info *finfo; >> + int err, orig_mtu; >> + bool standby; >> + >> + if (failover_ops) { >> + if (!failover_ops->slave_join) >> + return -EINVAL; >> + >> + return failover_ops->slave_join(slave_dev, failover_dev); >> + } >> + >> + if (netif_running(failover_dev)) { >> + err = dev_open(slave_dev); >> + if (err && (err != -EBUSY)) { >> + netdev_err(failover_dev, "Opening slave %s failed err:%d\n", >> + slave_dev->name, err); >> + goto err_dev_open; >> + } >> + } >> + >> + /* Align MTU of slave with failover dev */ >> + orig_mtu = slave_dev->mtu; > I suspect this was copied from bond. this variable is never > used and I'm even surprised gcc did not warn about this. Thanks for catching, I broke this when i moved the dev_open() and dev_set_mtu() calls from register to join. I need to reset slave_dev mtu to orig_mtu on failure. > > >> + err = dev_set_mtu(slave_dev, failover_dev->mtu); > How do we know slave supports this MTU? same applies to > failover_change_mtu. The err check below should catch it and we will reset the mtu back and fail the join/register. > > > > >> + if (err) { >> + netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n", >> + slave_dev->name, failover_dev->mtu); >> + goto err_set_mtu; >> + } >> + >> + finfo = netdev_priv(failover_dev); >> + standby = (slave_dev->dev.parent == failover_dev->dev.parent); >> + >> + dev_hold(slave_dev); >> + >> + if (standby) { >> + rcu_assign_pointer(finfo->standby_dev, slave_dev); >> + dev_get_stats(finfo->standby_dev, &finfo->standby_stats); >> + } else { >> + rcu_assign_pointer(finfo->primary_dev, slave_dev); >> + dev_get_stats(finfo->primary_dev, &finfo->primary_stats); >> + failover_dev->min_mtu = slave_dev->min_mtu; >> + failover_dev->max_mtu = slave_dev->max_mtu; >> + } >> + >> + netdev_info(failover_dev, "failover slave:%s joined\n", >> + slave_dev->name); >> + >> + return 0; >> + >> +err_set_mtu: >> + dev_close(slave_dev); >> +err_dev_open: >> + return err; >> +} >> + >> +/* Called when slave dev is injecting data into network stack. >> + * Change the associated network device from lower dev to virtio. >> + * note: already called with rcu_read_lock >> + */ >> +static rx_handler_result_t failover_handle_frame(struct sk_buff **pskb) >> +{ >> + struct sk_buff *skb = *pskb; >> + struct net_device *ndev = rcu_dereference(skb->dev->rx_handler_data); >> + >> + skb->dev = ndev; >> + >> + return RX_HANDLER_ANOTHER; >> +} >> + >> +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; >> +} >> + >> +static int failover_slave_register(struct net_device *slave_dev) >> +{ >> + struct failover_ops *failover_ops; >> + struct net_device *failover_dev; >> + int ret; >> + >> + ASSERT_RTNL(); >> + >> + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); >> + if (!failover_dev) >> + goto done; >> + >> + ret = failover_slave_pre_register(slave_dev, failover_dev, >> + failover_ops); >> + if (ret) >> + goto done; >> + >> + ret = netdev_rx_handler_register(slave_dev, failover_ops ? >> + failover_ops->handle_frame : >> + failover_handle_frame, failover_dev); >> + if (ret) { >> + netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n", >> + ret); >> + goto done; >> + } >> + >> + ret = netdev_upper_dev_link(slave_dev, failover_dev, NULL); >> + if (ret) { >> + netdev_err(slave_dev, "can not set failover device %s (err = %d)\n", >> + failover_dev->name, ret); >> + goto upper_link_failed; >> + } >> + >> + slave_dev->priv_flags |= IFF_FAILOVER_SLAVE; >> + >> + ret = failover_slave_join(slave_dev, failover_dev, failover_ops); >> + if (ret) >> + goto err_join; >> + >> + call_netdevice_notifiers(NETDEV_JOIN, slave_dev); >> + >> + netdev_info(failover_dev, "failover slave:%s registered\n", >> + slave_dev->name); >> + >> + goto done; >> + >> +err_join: >> + netdev_upper_dev_unlink(slave_dev, failover_dev); >> + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; >> +upper_link_failed: >> + netdev_rx_handler_unregister(slave_dev); >> +done: >> + return NOTIFY_DONE; >> +} >> + >> +static int failover_slave_pre_unregister(struct net_device *slave_dev, >> + struct net_device *failover_dev, >> + struct failover_ops *failover_ops) >> +{ >> + struct net_device *standby_dev, *primary_dev; >> + struct failover_info *finfo; >> + >> + if (failover_ops) { >> + if (!failover_ops->slave_pre_unregister) >> + return -EINVAL; >> + >> + return failover_ops->slave_pre_unregister(slave_dev, >> + failover_dev); >> + } >> + >> + finfo = netdev_priv(failover_dev); >> + primary_dev = rtnl_dereference(finfo->primary_dev); >> + standby_dev = rtnl_dereference(finfo->standby_dev); >> + >> + if (slave_dev != primary_dev && slave_dev != standby_dev) >> + return -EINVAL; >> + >> + return 0; >> +} >> + >> +static int failover_slave_release(struct net_device *slave_dev, >> + struct net_device *failover_dev, >> + struct failover_ops *failover_ops) >> +{ >> + struct net_device *standby_dev, *primary_dev; >> + struct failover_info *finfo; >> + >> + if (failover_ops) { >> + if (!failover_ops->slave_release) >> + return -EINVAL; >> + >> + return failover_ops->slave_release(slave_dev, failover_dev); >> + } >> + >> + finfo = netdev_priv(failover_dev); >> + primary_dev = rtnl_dereference(finfo->primary_dev); >> + standby_dev = rtnl_dereference(finfo->standby_dev); >> + >> + if (slave_dev == standby_dev) { >> + RCU_INIT_POINTER(finfo->standby_dev, NULL); >> + } else { >> + RCU_INIT_POINTER(finfo->primary_dev, NULL); >> + if (standby_dev) { >> + failover_dev->min_mtu = standby_dev->min_mtu; >> + failover_dev->max_mtu = standby_dev->max_mtu; >> + } >> + } >> + >> + dev_put(slave_dev); >> + >> + netdev_info(failover_dev, "failover slave:%s released\n", >> + slave_dev->name); >> + >> + return 0; >> +} >> + >> +int failover_slave_unregister(struct net_device *slave_dev) >> +{ >> + struct failover_ops *failover_ops; >> + struct net_device *failover_dev; >> + int ret; >> + >> + if (!netif_is_failover_slave(slave_dev)) >> + goto done; >> + >> + ASSERT_RTNL(); >> + >> + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); >> + if (!failover_dev) >> + goto done; >> + >> + ret = failover_slave_pre_unregister(slave_dev, failover_dev, >> + failover_ops); >> + if (ret) >> + goto done; >> + >> + netdev_rx_handler_unregister(slave_dev); >> + netdev_upper_dev_unlink(slave_dev, failover_dev); >> + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; >> + >> + failover_slave_release(slave_dev, failover_dev, failover_ops); > > Don't you need to get stats from it? This device is going away ... Yes. we need to update the failover_stats before the slave goes away. > >> + >> + netdev_info(failover_dev, "failover slave:%s unregistered\n", >> + slave_dev->name); >> + >> +done: >> + return NOTIFY_DONE; >> +} >> +EXPORT_SYMBOL_GPL(failover_slave_unregister); >> + >> +static bool failover_xmit_ready(struct net_device *dev) >> +{ >> + return netif_running(dev) && netif_carrier_ok(dev); >> +} >> + >> +static int failover_slave_link_change(struct net_device *slave_dev) >> +{ >> + struct net_device *failover_dev, *primary_dev, *standby_dev; >> + struct failover_ops *failover_ops; >> + struct failover_info *finfo; >> + >> + if (!netif_is_failover_slave(slave_dev)) >> + goto done; >> + >> + ASSERT_RTNL(); >> + >> + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); >> + if (!failover_dev) >> + goto done; >> + >> + if (failover_ops) { >> + if (!failover_ops->slave_link_change) >> + goto done; >> + >> + return failover_ops->slave_link_change(slave_dev, failover_dev); >> + } >> + >> + if (!netif_running(failover_dev)) >> + return 0; >> + >> + finfo = netdev_priv(failover_dev); >> + >> + primary_dev = rtnl_dereference(finfo->primary_dev); >> + standby_dev = rtnl_dereference(finfo->standby_dev); >> + >> + if (slave_dev != primary_dev && slave_dev != standby_dev) >> + goto done; >> + >> + if ((primary_dev && failover_xmit_ready(primary_dev)) || >> + (standby_dev && failover_xmit_ready(standby_dev))) { >> + netif_carrier_on(failover_dev); >> + netif_tx_wake_all_queues(failover_dev); >> + } else { >> + netif_carrier_off(failover_dev); >> + netif_tx_stop_all_queues(failover_dev); > And I think it's a good idea to get stats from device here too. Not sure why we need to get stats from lower devs here? > > >> + } >> + >> +done: >> + return NOTIFY_DONE; >> +} >> + >> +static bool failover_validate_event_dev(struct net_device *dev) >> +{ >> + /* Skip parent events */ >> + if (netif_is_failover(dev)) >> + return false; >> + >> + /* Avoid non-Ethernet type devices */ > ... for now. It would be possible easy to make this generic - > just copy things like type and addr_len from slave. ok. failover_create can copy these values from standby_dev and we can validate that they match when primary_dev registers. > >> + if (dev->type != ARPHRD_ETHER) >> + return false; >> + >> + return true; >> +} >> + >> +static int >> +failover_event(struct notifier_block *this, unsigned long event, void *ptr) >> +{ >> + struct net_device *event_dev = netdev_notifier_info_to_dev(ptr); >> + >> + if (!failover_validate_event_dev(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); >> + default: >> + return NOTIFY_DONE; >> + } >> +} >> + >> +static struct notifier_block failover_notifier = { >> + .notifier_call = failover_event, >> +}; >> + >> +static int failover_open(struct net_device *dev) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *primary_dev, *standby_dev; >> + int err; >> + >> + netif_carrier_off(dev); >> + netif_tx_wake_all_queues(dev); >> + >> + primary_dev = rtnl_dereference(finfo->primary_dev); >> + if (primary_dev) { >> + err = dev_open(primary_dev); >> + if (err) >> + goto err_primary_open; >> + } >> + >> + standby_dev = rtnl_dereference(finfo->standby_dev); >> + if (standby_dev) { >> + err = dev_open(standby_dev); >> + if (err) >> + goto err_standby_open; >> + } >> + >> + return 0; >> + >> +err_standby_open: >> + dev_close(primary_dev); >> +err_primary_open: >> + netif_tx_disable(dev); >> + return err; >> +} >> + >> +static int failover_close(struct net_device *dev) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *slave_dev; >> + >> + netif_tx_disable(dev); >> + >> + slave_dev = rtnl_dereference(finfo->primary_dev); >> + if (slave_dev) >> + dev_close(slave_dev); >> + >> + slave_dev = rtnl_dereference(finfo->standby_dev); >> + if (slave_dev) >> + dev_close(slave_dev); >> + >> + return 0; >> +} >> + >> +static netdev_tx_t failover_drop_xmit(struct sk_buff *skb, >> + struct net_device *dev) >> +{ >> + atomic_long_inc(&dev->tx_dropped); >> + dev_kfree_skb_any(skb); >> + return NETDEV_TX_OK; >> +} >> + >> +static netdev_tx_t failover_start_xmit(struct sk_buff *skb, >> + struct net_device *dev) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *xmit_dev; >> + >> + /* Try xmit via primary netdev followed by standby netdev */ >> + xmit_dev = rcu_dereference_bh(finfo->primary_dev); >> + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) { >> + xmit_dev = rcu_dereference_bh(finfo->standby_dev); >> + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) >> + return failover_drop_xmit(skb, dev); >> + } >> + >> + skb->dev = xmit_dev; >> + skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping; >> + >> + return dev_queue_xmit(skb); >> +} > Is this going through qdisc twice? Won't this hurt performance > measureably? The failover dev has no queue (IFF_NO_QUEUE) , so doesn't go through qdisc twice. > >> + >> +static u16 failover_select_queue(struct net_device *dev, struct sk_buff *skb, >> + void *accel_priv, >> + select_queue_fallback_t fallback) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *primary_dev; >> + u16 txq; >> + >> + rcu_read_lock(); >> + primary_dev = rcu_dereference(finfo->primary_dev); >> + if (primary_dev) { >> + const struct net_device_ops *ops = primary_dev->netdev_ops; >> + >> + if (ops->ndo_select_queue) >> + txq = ops->ndo_select_queue(primary_dev, skb, >> + accel_priv, fallback); >> + else >> + txq = fallback(primary_dev, skb); >> + >> + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; >> + >> + return txq; >> + } >> + >> + txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0; >> + >> + /* Save the original txq to restore before passing to the driver */ >> + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; >> + >> + if (unlikely(txq >= dev->real_num_tx_queues)) { >> + do { >> + txq -= dev->real_num_tx_queues; >> + } while (txq >= dev->real_num_tx_queues); >> + } >> + >> + return txq; >> +} >> + >> +/* fold stats, assuming all rtnl_link_stats64 fields are u64, but >> + * that some drivers can provide 32finfot values only. >> + */ >> +static void failover_fold_stats(struct rtnl_link_stats64 *_res, >> + const struct rtnl_link_stats64 *_new, >> + const struct rtnl_link_stats64 *_old) >> +{ >> + const u64 *new = (const u64 *)_new; >> + const u64 *old = (const u64 *)_old; >> + u64 *res = (u64 *)_res; >> + int i; >> + >> + for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) { >> + u64 nv = new[i]; >> + u64 ov = old[i]; >> + s64 delta = nv - ov; >> + >> + /* detects if this particular field is 32bit only */ >> + if (((nv | ov) >> 32) == 0) >> + delta = (s64)(s32)((u32)nv - (u32)ov); >> + >> + /* filter anomalies, some drivers reset their stats >> + * at down/up events. >> + */ >> + if (delta > 0) >> + res[i] += delta; >> + } >> +} >> + >> +static void failover_get_stats(struct net_device *dev, >> + struct rtnl_link_stats64 *stats) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + const struct rtnl_link_stats64 *new; >> + struct rtnl_link_stats64 temp; >> + struct net_device *slave_dev; >> + >> + spin_lock(&finfo->stats_lock); >> + memcpy(stats, &finfo->failover_stats, sizeof(*stats)); >> + >> + rcu_read_lock(); >> + >> + slave_dev = rcu_dereference(finfo->primary_dev); >> + if (slave_dev) { >> + new = dev_get_stats(slave_dev, &temp); >> + failover_fold_stats(stats, new, &finfo->primary_stats); >> + memcpy(&finfo->primary_stats, new, sizeof(*new)); >> + } >> + >> + slave_dev = rcu_dereference(finfo->standby_dev); >> + if (slave_dev) { >> + new = dev_get_stats(slave_dev, &temp); >> + failover_fold_stats(stats, new, &finfo->standby_stats); >> + memcpy(&finfo->standby_stats, new, sizeof(*new)); >> + } >> + >> + rcu_read_unlock(); >> + >> + memcpy(&finfo->failover_stats, stats, sizeof(*stats)); >> + spin_unlock(&finfo->stats_lock); >> +} >> + >> +static int failover_change_mtu(struct net_device *dev, int new_mtu) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *primary_dev, *standby_dev; >> + int ret = 0; >> + >> + primary_dev = rcu_dereference(finfo->primary_dev); >> + if (primary_dev) { >> + ret = dev_set_mtu(primary_dev, new_mtu); >> + if (ret) >> + return ret; >> + } >> + >> + standby_dev = rcu_dereference(finfo->standby_dev); >> + if (standby_dev) { >> + ret = dev_set_mtu(standby_dev, new_mtu); >> + if (ret) { >> + dev_set_mtu(primary_dev, dev->mtu); >> + return ret; >> + } >> + } >> + >> + dev->mtu = new_mtu; >> + return 0; >> +} >> + >> +static void failover_set_rx_mode(struct net_device *dev) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *slave_dev; >> + >> + rcu_read_lock(); >> + >> + slave_dev = rcu_dereference(finfo->primary_dev); >> + if (slave_dev) { >> + dev_uc_sync_multiple(slave_dev, dev); >> + dev_mc_sync_multiple(slave_dev, dev); >> + } >> + >> + slave_dev = rcu_dereference(finfo->standby_dev); >> + if (slave_dev) { >> + dev_uc_sync_multiple(slave_dev, dev); >> + dev_mc_sync_multiple(slave_dev, dev); >> + } >> + >> + rcu_read_unlock(); >> +} >> + >> +static const struct net_device_ops failover_dev_ops = { >> + .ndo_open = failover_open, >> + .ndo_stop = failover_close, >> + .ndo_start_xmit = failover_start_xmit, >> + .ndo_select_queue = failover_select_queue, >> + .ndo_get_stats64 = failover_get_stats, >> + .ndo_change_mtu = failover_change_mtu, >> + .ndo_set_rx_mode = failover_set_rx_mode, >> + .ndo_validate_addr = eth_validate_addr, >> + .ndo_features_check = passthru_features_check, > xdp support? I think it should be possible to add it be calling the lower dev ndo_xdp routines with proper checks. can we add this later? > >> +}; >> + >> +#define FAILOVER_NAME "failover" >> +#define FAILOVER_VERSION "0.1" >> + >> +static void failover_ethtool_get_drvinfo(struct net_device *dev, >> + struct ethtool_drvinfo *drvinfo) >> +{ >> + strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver)); >> + strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version)); >> +} >> + >> +int failover_ethtool_get_link_ksettings(struct net_device *dev, >> + struct ethtool_link_ksettings *cmd) >> +{ >> + struct failover_info *finfo = netdev_priv(dev); >> + struct net_device *slave_dev; >> + >> + slave_dev = rtnl_dereference(finfo->primary_dev); >> + if (!slave_dev || !failover_xmit_ready(slave_dev)) { >> + slave_dev = rtnl_dereference(finfo->standby_dev); >> + if (!slave_dev || !failover_xmit_ready(slave_dev)) { >> + cmd->base.duplex = DUPLEX_UNKNOWN; >> + cmd->base.port = PORT_OTHER; >> + cmd->base.speed = SPEED_UNKNOWN; >> + >> + return 0; >> + } >> + } >> + >> + return __ethtool_get_link_ksettings(slave_dev, cmd); >> +} >> +EXPORT_SYMBOL_GPL(failover_ethtool_get_link_ksettings); >> + >> +static const struct ethtool_ops failover_ethtool_ops = { >> + .get_drvinfo = failover_ethtool_get_drvinfo, >> + .get_link = ethtool_op_get_link, >> + .get_link_ksettings = failover_ethtool_get_link_ksettings, >> +}; >> + >> +static void failover_register_existing_slave(struct net_device *failover_dev) >> +{ >> + struct net *net = dev_net(failover_dev); >> + struct net_device *dev; >> + >> + rtnl_lock(); >> + for_each_netdev(net, dev) { >> + if (dev == failover_dev) >> + continue; >> + if (!failover_validate_event_dev(dev)) >> + continue; >> + if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr)) >> + failover_slave_register(dev); >> + } >> + rtnl_unlock(); >> +} >> + >> +int failover_register(struct net_device *dev, struct failover_ops *ops, >> + struct failover **pfailover) >> +{ >> + struct failover *failover; >> + >> + failover = kzalloc(sizeof(*failover), GFP_KERNEL); >> + if (!failover) >> + return -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); >> + >> + failover_register_existing_slave(dev); >> + >> + *pfailover = failover; >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(failover_register); >> + >> +void failover_unregister(struct failover *failover) >> +{ >> + struct net_device *failover_dev; >> + >> + failover_dev = rcu_dereference(failover->failover_dev); >> + >> + 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); >> + >> +int failover_create(struct net_device *standby_dev, struct failover **pfailover) >> +{ >> + struct device *dev = standby_dev->dev.parent; >> + struct net_device *failover_dev; >> + int err; >> + >> + /* Alloc at least 2 queues, for now we are going with 16 assuming >> + * that most devices being bonded won't have too many queues. >> + */ >> + failover_dev = alloc_etherdev_mq(sizeof(struct failover_info), 16); >> + if (!failover_dev) { >> + dev_err(dev, "Unable to allocate failover_netdev!\n"); >> + return -ENOMEM; >> + } >> + >> + dev_net_set(failover_dev, dev_net(standby_dev)); >> + SET_NETDEV_DEV(failover_dev, dev); >> + >> + failover_dev->netdev_ops = &failover_dev_ops; >> + failover_dev->ethtool_ops = &failover_ethtool_ops; >> + >> + /* Initialize the device options */ >> + failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE; >> + failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | >> + IFF_TX_SKB_SHARING); >> + >> + /* don't acquire failover netdev's netif_tx_lock when transmitting */ >> + failover_dev->features |= NETIF_F_LLTX; >> + >> + /* Don't allow failover devices to change network namespaces. */ >> + failover_dev->features |= NETIF_F_NETNS_LOCAL; >> + >> + failover_dev->hw_features = NETIF_F_HW_CSUM | NETIF_F_SG | >> + NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | >> + NETIF_F_HIGHDMA | NETIF_F_LRO; > OK but then you must make sure your primary and standby both > support these features. I guess i need to add something like bond_compute_features() to handle this. > >> + >> + failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL; >> + failover_dev->features |= failover_dev->hw_features; >> + >> + memcpy(failover_dev->dev_addr, standby_dev->dev_addr, >> + failover_dev->addr_len); >> + >> + failover_dev->min_mtu = standby_dev->min_mtu; >> + failover_dev->max_mtu = standby_dev->max_mtu; > OK MTU is copied, fine. But is this always enough? > > How about e.g. hard_header_len? min_header_len? needed_headroom? > needed_tailroom? I'd worry that even if you cover existing ones more > might be added with time. A function copying config between devices > probably belongs in some central place IMHO. ok. will add a function that handles these fields too. > > >> + >> + err = register_netdev(failover_dev); >> + if (err < 0) { >> + dev_err(dev, "Unable to register failover_dev!\n"); >> + goto err_register_netdev; >> + } >> + >> + netif_carrier_off(failover_dev); >> + >> + err = failover_register(failover_dev, NULL, pfailover); >> + if (err < 0) >> + goto err_failover; >> + >> + return 0; >> + >> +err_failover: >> + unregister_netdev(failover_dev); >> +err_register_netdev: >> + free_netdev(failover_dev); >> + >> + return err; >> +} >> +EXPORT_SYMBOL_GPL(failover_create); >> + >> +void failover_destroy(struct failover *failover) >> +{ >> + struct net_device *failover_dev; >> + struct net_device *slave_dev; >> + struct failover_info *finfo; >> + >> + if (!failover) >> + return; >> + >> + failover_dev = rcu_dereference(failover->failover_dev); >> + finfo = netdev_priv(failover_dev); >> + >> + netif_device_detach(failover_dev); >> + >> + rtnl_lock(); >> + >> + slave_dev = rtnl_dereference(finfo->primary_dev); >> + if (slave_dev) >> + failover_slave_unregister(slave_dev); >> + >> + slave_dev = rtnl_dereference(finfo->standby_dev); >> + if (slave_dev) >> + failover_slave_unregister(slave_dev); >> + >> + failover_unregister(failover); >> + >> + unregister_netdevice(failover_dev); >> + >> + rtnl_unlock(); >> + >> + free_netdev(failover_dev); >> +} >> +EXPORT_SYMBOL_GPL(failover_destroy); >> + >> +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("Failover infrastructure/interface for Paravirtual drivers"); >> +MODULE_LICENSE("GPL v2"); >> -- >> 2.14.3
On Fri, Apr 20, 2018 at 08:21:00AM -0700, Samudrala, Sridhar wrote: > > > + finfo = netdev_priv(failover_dev); > > > + > > > + primary_dev = rtnl_dereference(finfo->primary_dev); > > > + standby_dev = rtnl_dereference(finfo->standby_dev); > > > + > > > + if (slave_dev != primary_dev && slave_dev != standby_dev) > > > + goto done; > > > + > > > + if ((primary_dev && failover_xmit_ready(primary_dev)) || > > > + (standby_dev && failover_xmit_ready(standby_dev))) { > > > + netif_carrier_on(failover_dev); > > > + netif_tx_wake_all_queues(failover_dev); > > > + } else { > > > + netif_carrier_off(failover_dev); > > > + netif_tx_stop_all_queues(failover_dev); > > And I think it's a good idea to get stats from device here too. > > Not sure why we need to get stats from lower devs here? link down is often indication of a hardware problem. lower dev might stop responding down the road. > > > +static const struct net_device_ops failover_dev_ops = { > > > + .ndo_open = failover_open, > > > + .ndo_stop = failover_close, > > > + .ndo_start_xmit = failover_start_xmit, > > > + .ndo_select_queue = failover_select_queue, > > > + .ndo_get_stats64 = failover_get_stats, > > > + .ndo_change_mtu = failover_change_mtu, > > > + .ndo_set_rx_mode = failover_set_rx_mode, > > > + .ndo_validate_addr = eth_validate_addr, > > > + .ndo_features_check = passthru_features_check, > > xdp support? > > I think it should be possible to add it be calling the lower dev ndo_xdp routines > with proper checks. can we add this later? I'd be concerned that if you don't xdp userspace will keep poking at lower devs. Then it will stop working if you add this later.
On Fri, Apr 20, 2018 at 8:34 AM, Michael S. Tsirkin <mst@redhat.com> wrote: > On Fri, Apr 20, 2018 at 08:21:00AM -0700, Samudrala, Sridhar wrote: >> > > + finfo = netdev_priv(failover_dev); >> > > + >> > > + primary_dev = rtnl_dereference(finfo->primary_dev); >> > > + standby_dev = rtnl_dereference(finfo->standby_dev); >> > > + >> > > + if (slave_dev != primary_dev && slave_dev != standby_dev) >> > > + goto done; >> > > + >> > > + if ((primary_dev && failover_xmit_ready(primary_dev)) || >> > > + (standby_dev && failover_xmit_ready(standby_dev))) { >> > > + netif_carrier_on(failover_dev); >> > > + netif_tx_wake_all_queues(failover_dev); >> > > + } else { >> > > + netif_carrier_off(failover_dev); >> > > + netif_tx_stop_all_queues(failover_dev); >> > And I think it's a good idea to get stats from device here too. >> >> Not sure why we need to get stats from lower devs here? > > link down is often indication of a hardware problem. > lower dev might stop responding down the road. > >> > > +static const struct net_device_ops failover_dev_ops = { >> > > + .ndo_open = failover_open, >> > > + .ndo_stop = failover_close, >> > > + .ndo_start_xmit = failover_start_xmit, >> > > + .ndo_select_queue = failover_select_queue, >> > > + .ndo_get_stats64 = failover_get_stats, >> > > + .ndo_change_mtu = failover_change_mtu, >> > > + .ndo_set_rx_mode = failover_set_rx_mode, >> > > + .ndo_validate_addr = eth_validate_addr, >> > > + .ndo_features_check = passthru_features_check, >> > xdp support? >> >> I think it should be possible to add it be calling the lower dev ndo_xdp routines >> with proper checks. can we add this later? > > I'd be concerned that if you don't xdp userspace will keep poking > at lower devs. Then it will stop working if you add this later. The failover device is better off not providing in-driver XDP since there are already skbs allocated by the time that we see the packet here anyway. As such generic XDP is the preferred way to handle this since it will work regardless of what lower devices are present. The only advantage of having XDP down at the virtio or VF level would be that it performs better, but at the cost of complexity since we would need to rebind the eBPF program any time a device is hotplugged out and then back in. For now the current approach is in keeping with how bonding and other similar drivers are currently handling this. Thanks. - Alex
On Fri, Apr 20, 2018 at 08:56:57AM -0700, Alexander Duyck wrote: > On Fri, Apr 20, 2018 at 8:34 AM, Michael S. Tsirkin <mst@redhat.com> wrote: > > On Fri, Apr 20, 2018 at 08:21:00AM -0700, Samudrala, Sridhar wrote: > >> > > + finfo = netdev_priv(failover_dev); > >> > > + > >> > > + primary_dev = rtnl_dereference(finfo->primary_dev); > >> > > + standby_dev = rtnl_dereference(finfo->standby_dev); > >> > > + > >> > > + if (slave_dev != primary_dev && slave_dev != standby_dev) > >> > > + goto done; > >> > > + > >> > > + if ((primary_dev && failover_xmit_ready(primary_dev)) || > >> > > + (standby_dev && failover_xmit_ready(standby_dev))) { > >> > > + netif_carrier_on(failover_dev); > >> > > + netif_tx_wake_all_queues(failover_dev); > >> > > + } else { > >> > > + netif_carrier_off(failover_dev); > >> > > + netif_tx_stop_all_queues(failover_dev); > >> > And I think it's a good idea to get stats from device here too. > >> > >> Not sure why we need to get stats from lower devs here? > > > > link down is often indication of a hardware problem. > > lower dev might stop responding down the road. > > > >> > > +static const struct net_device_ops failover_dev_ops = { > >> > > + .ndo_open = failover_open, > >> > > + .ndo_stop = failover_close, > >> > > + .ndo_start_xmit = failover_start_xmit, > >> > > + .ndo_select_queue = failover_select_queue, > >> > > + .ndo_get_stats64 = failover_get_stats, > >> > > + .ndo_change_mtu = failover_change_mtu, > >> > > + .ndo_set_rx_mode = failover_set_rx_mode, > >> > > + .ndo_validate_addr = eth_validate_addr, > >> > > + .ndo_features_check = passthru_features_check, > >> > xdp support? > >> > >> I think it should be possible to add it be calling the lower dev ndo_xdp routines > >> with proper checks. can we add this later? > > > > I'd be concerned that if you don't xdp userspace will keep poking > > at lower devs. Then it will stop working if you add this later. > > The failover device is better off not providing in-driver XDP since > there are already skbs allocated by the time that we see the packet > here anyway. As such generic XDP is the preferred way to handle this > since it will work regardless of what lower devices are present. > > The only advantage of having XDP down at the virtio or VF level would > be that it performs better, but at the cost of complexity since we > would need to rebind the eBPF program any time a device is hotplugged > out and then back in. For now the current approach is in keeping with > how bonding and other similar drivers are currently handling this. > > Thanks. > > - Alex OK fair enough.
On Thu, Apr 19, 2018 at 06:42:02PM -0700, Sridhar Samudrala wrote: > +#if IS_ENABLED(CONFIG_NET_FAILOVER) > + > +int failover_create(struct net_device *standby_dev, > + struct failover **pfailover); Should we rename all these structs net_failover? It's possible to extend the concept to storage I think. > +void failover_destroy(struct failover *failover); > + > +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, > + struct failover **pfailover); > +void failover_unregister(struct failover *failover); > + > +int failover_slave_unregister(struct net_device *slave_dev); > + > +#else > + > +static inline > +int failover_create(struct net_device *standby_dev, > + struct failover **pfailover); > +{ > + return 0; Does this make callers do something sane? Shouldn't these return an error? > +} > + > +static inline > +void failover_destroy(struct failover *failover) > +{ > +} > + > +static inline > +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, > + struct pfailover **pfailover); > +{ > + return 0; > +} struct pfailover seems like a typo. > + > +static inline > +void failover_unregister(struct failover *failover) > +{ > +} > + > +static inline > +int failover_slave_unregister(struct net_device *slave_dev) > +{ > + return 0; > +} Does anyone test return value of unregister? should this be void? > + > +#endif > + > +#endif /* _NET_FAILOVER_H */
Hi Sridhar,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on net/master]
[also build test WARNING on v4.17-rc1]
[cannot apply to net-next/master next-20180420]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Sridhar-Samudrala/Enable-virtio_net-to-act-as-a-standby-for-a-passthru-device/20180422-210557
reproduce:
# apt-get install sparse
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
>> net/core/failover.c:99:36: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct net_device *dev @@ got struct net_devicestruct net_device *dev @@
net/core/failover.c:99:36: expected struct net_device *dev
net/core/failover.c:99:36: got struct net_device [noderef] <asn:4>*standby_dev
net/core/failover.c:102:36: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct net_device *dev @@ got struct net_devicestruct net_device *dev @@
net/core/failover.c:102:36: expected struct net_device *dev
net/core/failover.c:102:36: got struct net_device [noderef] <asn:4>*primary_dev
>> net/core/failover.c:468:12: sparse: context imbalance in 'failover_select_queue' - wrong count at exit
vim +99 net/core/failover.c
58
59 static int failover_slave_join(struct net_device *slave_dev,
60 struct net_device *failover_dev,
61 struct failover_ops *failover_ops)
62 {
63 struct failover_info *finfo;
64 int err, orig_mtu;
65 bool standby;
66
67 if (failover_ops) {
68 if (!failover_ops->slave_join)
69 return -EINVAL;
70
71 return failover_ops->slave_join(slave_dev, failover_dev);
72 }
73
74 if (netif_running(failover_dev)) {
75 err = dev_open(slave_dev);
76 if (err && (err != -EBUSY)) {
77 netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
78 slave_dev->name, err);
79 goto err_dev_open;
80 }
81 }
82
83 /* Align MTU of slave with failover dev */
84 orig_mtu = slave_dev->mtu;
85 err = dev_set_mtu(slave_dev, failover_dev->mtu);
86 if (err) {
87 netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n",
88 slave_dev->name, failover_dev->mtu);
89 goto err_set_mtu;
90 }
91
92 finfo = netdev_priv(failover_dev);
93 standby = (slave_dev->dev.parent == failover_dev->dev.parent);
94
95 dev_hold(slave_dev);
96
97 if (standby) {
98 rcu_assign_pointer(finfo->standby_dev, slave_dev);
> 99 dev_get_stats(finfo->standby_dev, &finfo->standby_stats);
100 } else {
101 rcu_assign_pointer(finfo->primary_dev, slave_dev);
102 dev_get_stats(finfo->primary_dev, &finfo->primary_stats);
103 failover_dev->min_mtu = slave_dev->min_mtu;
104 failover_dev->max_mtu = slave_dev->max_mtu;
105 }
106
107 netdev_info(failover_dev, "failover slave:%s joined\n",
108 slave_dev->name);
109
110 return 0;
111
112 err_set_mtu:
113 dev_close(slave_dev);
114 err_dev_open:
115 return err;
116 }
117
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 4/22/2018 10:06 AM, Michael S. Tsirkin wrote: > On Thu, Apr 19, 2018 at 06:42:02PM -0700, Sridhar Samudrala wrote: >> +#if IS_ENABLED(CONFIG_NET_FAILOVER) >> + >> +int failover_create(struct net_device *standby_dev, >> + struct failover **pfailover); > Should we rename all these structs net_failover? > It's possible to extend the concept to storage I think. We could, the only downside is that the names become longer. i think we need to change the filenames and the function names also to be consistent. > >> +void failover_destroy(struct failover *failover); >> + >> +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, >> + struct failover **pfailover); >> +void failover_unregister(struct failover *failover); >> + >> +int failover_slave_unregister(struct net_device *slave_dev); >> + >> +#else >> + >> +static inline >> +int failover_create(struct net_device *standby_dev, >> + struct failover **pfailover); >> +{ >> + return 0; > Does this make callers do something sane? > Shouldn't these return an error? Yes. i think i should return -EOPNOTSUPP here, so that we fail when CONFIG_NET_FAILOVER is not enabled and the virtio-net driver is trying to create a failover device. >> +} >> + >> +static inline >> +void failover_destroy(struct failover *failover) >> +{ >> +} >> + >> +static inline >> +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, >> + struct pfailover **pfailover); >> +{ >> + return 0; >> +} > struct pfailover seems like a typo. yes. will also change the return to -EOPNOTSUPP > >> + >> +static inline >> +void failover_unregister(struct failover *failover) >> +{ >> +} >> + >> +static inline >> +int failover_slave_unregister(struct net_device *slave_dev) >> +{ >> + return 0; >> +} > Does anyone test return value of unregister? > should this be void? yes. can be changed to void. > >> + >> +#endif >> + >> +#endif /* _NET_FAILOVER_H */
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cf44503ea81a..ed535b6724e1 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1401,6 +1401,8 @@ 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, @@ -1430,6 +1432,8 @@ 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 @@ -1458,6 +1462,8 @@ 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. @@ -4308,6 +4314,16 @@ 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) { diff --git a/include/net/failover.h b/include/net/failover.h new file mode 100644 index 000000000000..0b8601043d90 --- /dev/null +++ b/include/net/failover.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2018, Intel Corporation. */ + +#ifndef _NET_FAILOVER_H +#define _NET_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_join)(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_release)(struct net_device *slave_dev, + struct net_device *failover_dev); + int (*slave_link_change)(struct net_device *slave_dev, + struct net_device *failover_dev); + rx_handler_result_t (*handle_frame)(struct sk_buff **pskb); +}; + +struct failover { + struct list_head list; + struct net_device __rcu *failover_dev; + struct failover_ops __rcu *ops; +}; + +/* failover state */ +struct failover_info { + /* primary netdev with same MAC */ + struct net_device __rcu *primary_dev; + + /* standby netdev */ + struct net_device __rcu *standby_dev; + + /* primary netdev stats */ + struct rtnl_link_stats64 primary_stats; + + /* standby netdev stats */ + struct rtnl_link_stats64 standby_stats; + + /* aggregated stats */ + struct rtnl_link_stats64 failover_stats; + + /* spinlock while updating stats */ + spinlock_t stats_lock; +}; + +#if IS_ENABLED(CONFIG_NET_FAILOVER) + +int failover_create(struct net_device *standby_dev, + struct failover **pfailover); +void failover_destroy(struct failover *failover); + +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, + struct failover **pfailover); +void failover_unregister(struct failover *failover); + +int failover_slave_unregister(struct net_device *slave_dev); + +#else + +static inline +int failover_create(struct net_device *standby_dev, + struct failover **pfailover); +{ + return 0; +} + +static inline +void failover_destroy(struct failover *failover) +{ +} + +static inline +int failover_register(struct net_device *standby_dev, struct failover_ops *ops, + struct pfailover **pfailover); +{ + return 0; +} + +static inline +void failover_unregister(struct failover *failover) +{ +} + +static inline +int failover_slave_unregister(struct net_device *slave_dev) +{ + return 0; +} + +#endif + +#endif /* _NET_FAILOVER_H */ diff --git a/net/Kconfig b/net/Kconfig index 0428f12c25c2..388b99dfee10 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -423,6 +423,24 @@ config MAY_USE_DEVLINK on MAY_USE_DEVLINK to ensure they do not cause link errors when devlink is a loadable module and the driver using it is built-in. +config NET_FAILOVER + tristate "Failover interface" + help + This provides a generic interface for paravirtual drivers to listen + for netdev register/unregister/link change events from pci ethernet + devices with the same MAC and takeover their datapath. This also + enables live migration of a VM with direct attached VF by failing + over to the paravirtual datapath when the VF is unplugged. + +config MAY_USE_FAILOVER + tristate + default m if NET_FAILOVER=m + default y if NET_FAILOVER=y || NET_FAILOVER=n + help + Drivers using the failover infrastructure should have a dependency + on MAY_USE_FAILOVER to ensure they do not cause link errors when + failover is a loadable module and the driver using it is built-in. + 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 6dbbba8c57ae..cef17518bb7d 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -30,3 +30,4 @@ 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_NET_FAILOVER) += failover.o diff --git a/net/core/failover.c b/net/core/failover.c new file mode 100644 index 000000000000..7bee762cb737 --- /dev/null +++ b/net/core/failover.c @@ -0,0 +1,844 @@ +// 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 <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/ethtool.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/netdevice.h> +#include <linux/netpoll.h> +#include <linux/rtnetlink.h> +#include <linux/if_vlan.h> +#include <linux/pci.h> +#include <net/sch_generic.h> +#include <uapi/linux/if_arp.h> +#include <net/failover.h> + +static LIST_HEAD(failover_list); +static DEFINE_SPINLOCK(failover_lock); + +static int failover_slave_pre_register(struct net_device *slave_dev, + struct net_device *failover_dev, + struct failover_ops *failover_ops) +{ + struct failover_info *finfo; + bool standby; + + if (failover_ops) { + if (!failover_ops->slave_pre_register) + return -EINVAL; + + return failover_ops->slave_pre_register(slave_dev, + failover_dev); + } + + finfo = netdev_priv(failover_dev); + standby = (slave_dev->dev.parent == failover_dev->dev.parent); + if (standby ? rtnl_dereference(finfo->standby_dev) : + rtnl_dereference(finfo->primary_dev)) { + netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n", + slave_dev->name, standby ? "standby" : "primary"); + return -EEXIST; + } + + /* Avoid non pci devices as primary netdev */ + if (!standby && (!slave_dev->dev.parent || + !dev_is_pci(slave_dev->dev.parent))) + return -EINVAL; + + return 0; +} + +static int failover_slave_join(struct net_device *slave_dev, + struct net_device *failover_dev, + struct failover_ops *failover_ops) +{ + struct failover_info *finfo; + int err, orig_mtu; + bool standby; + + if (failover_ops) { + if (!failover_ops->slave_join) + return -EINVAL; + + return failover_ops->slave_join(slave_dev, failover_dev); + } + + if (netif_running(failover_dev)) { + err = dev_open(slave_dev); + if (err && (err != -EBUSY)) { + netdev_err(failover_dev, "Opening slave %s failed err:%d\n", + slave_dev->name, err); + goto err_dev_open; + } + } + + /* Align MTU of slave with failover dev */ + orig_mtu = slave_dev->mtu; + err = dev_set_mtu(slave_dev, failover_dev->mtu); + if (err) { + netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n", + slave_dev->name, failover_dev->mtu); + goto err_set_mtu; + } + + finfo = netdev_priv(failover_dev); + standby = (slave_dev->dev.parent == failover_dev->dev.parent); + + dev_hold(slave_dev); + + if (standby) { + rcu_assign_pointer(finfo->standby_dev, slave_dev); + dev_get_stats(finfo->standby_dev, &finfo->standby_stats); + } else { + rcu_assign_pointer(finfo->primary_dev, slave_dev); + dev_get_stats(finfo->primary_dev, &finfo->primary_stats); + failover_dev->min_mtu = slave_dev->min_mtu; + failover_dev->max_mtu = slave_dev->max_mtu; + } + + netdev_info(failover_dev, "failover slave:%s joined\n", + slave_dev->name); + + return 0; + +err_set_mtu: + dev_close(slave_dev); +err_dev_open: + return err; +} + +/* Called when slave dev is injecting data into network stack. + * Change the associated network device from lower dev to virtio. + * note: already called with rcu_read_lock + */ +static rx_handler_result_t failover_handle_frame(struct sk_buff **pskb) +{ + struct sk_buff *skb = *pskb; + struct net_device *ndev = rcu_dereference(skb->dev->rx_handler_data); + + skb->dev = ndev; + + return RX_HANDLER_ANOTHER; +} + +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; +} + +static int failover_slave_register(struct net_device *slave_dev) +{ + struct failover_ops *failover_ops; + struct net_device *failover_dev; + int ret; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); + if (!failover_dev) + goto done; + + ret = failover_slave_pre_register(slave_dev, failover_dev, + failover_ops); + if (ret) + goto done; + + ret = netdev_rx_handler_register(slave_dev, failover_ops ? + failover_ops->handle_frame : + failover_handle_frame, failover_dev); + if (ret) { + netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n", + ret); + goto done; + } + + ret = netdev_upper_dev_link(slave_dev, failover_dev, NULL); + if (ret) { + netdev_err(slave_dev, "can not set failover device %s (err = %d)\n", + failover_dev->name, ret); + goto upper_link_failed; + } + + slave_dev->priv_flags |= IFF_FAILOVER_SLAVE; + + ret = failover_slave_join(slave_dev, failover_dev, failover_ops); + if (ret) + goto err_join; + + call_netdevice_notifiers(NETDEV_JOIN, slave_dev); + + netdev_info(failover_dev, "failover slave:%s registered\n", + slave_dev->name); + + goto done; + +err_join: + netdev_upper_dev_unlink(slave_dev, failover_dev); + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; +upper_link_failed: + netdev_rx_handler_unregister(slave_dev); +done: + return NOTIFY_DONE; +} + +static int failover_slave_pre_unregister(struct net_device *slave_dev, + struct net_device *failover_dev, + struct failover_ops *failover_ops) +{ + struct net_device *standby_dev, *primary_dev; + struct failover_info *finfo; + + if (failover_ops) { + if (!failover_ops->slave_pre_unregister) + return -EINVAL; + + return failover_ops->slave_pre_unregister(slave_dev, + failover_dev); + } + + finfo = netdev_priv(failover_dev); + primary_dev = rtnl_dereference(finfo->primary_dev); + standby_dev = rtnl_dereference(finfo->standby_dev); + + if (slave_dev != primary_dev && slave_dev != standby_dev) + return -EINVAL; + + return 0; +} + +static int failover_slave_release(struct net_device *slave_dev, + struct net_device *failover_dev, + struct failover_ops *failover_ops) +{ + struct net_device *standby_dev, *primary_dev; + struct failover_info *finfo; + + if (failover_ops) { + if (!failover_ops->slave_release) + return -EINVAL; + + return failover_ops->slave_release(slave_dev, failover_dev); + } + + finfo = netdev_priv(failover_dev); + primary_dev = rtnl_dereference(finfo->primary_dev); + standby_dev = rtnl_dereference(finfo->standby_dev); + + if (slave_dev == standby_dev) { + RCU_INIT_POINTER(finfo->standby_dev, NULL); + } else { + RCU_INIT_POINTER(finfo->primary_dev, NULL); + if (standby_dev) { + failover_dev->min_mtu = standby_dev->min_mtu; + failover_dev->max_mtu = standby_dev->max_mtu; + } + } + + dev_put(slave_dev); + + netdev_info(failover_dev, "failover slave:%s released\n", + slave_dev->name); + + return 0; +} + +int failover_slave_unregister(struct net_device *slave_dev) +{ + struct failover_ops *failover_ops; + struct net_device *failover_dev; + int ret; + + if (!netif_is_failover_slave(slave_dev)) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); + if (!failover_dev) + goto done; + + ret = failover_slave_pre_unregister(slave_dev, failover_dev, + failover_ops); + if (ret) + goto done; + + netdev_rx_handler_unregister(slave_dev); + netdev_upper_dev_unlink(slave_dev, failover_dev); + slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; + + failover_slave_release(slave_dev, failover_dev, failover_ops); + + netdev_info(failover_dev, "failover slave:%s unregistered\n", + slave_dev->name); + +done: + return NOTIFY_DONE; +} +EXPORT_SYMBOL_GPL(failover_slave_unregister); + +static bool failover_xmit_ready(struct net_device *dev) +{ + return netif_running(dev) && netif_carrier_ok(dev); +} + +static int failover_slave_link_change(struct net_device *slave_dev) +{ + struct net_device *failover_dev, *primary_dev, *standby_dev; + struct failover_ops *failover_ops; + struct failover_info *finfo; + + if (!netif_is_failover_slave(slave_dev)) + goto done; + + ASSERT_RTNL(); + + failover_dev = failover_get_bymac(slave_dev->perm_addr, &failover_ops); + if (!failover_dev) + goto done; + + if (failover_ops) { + if (!failover_ops->slave_link_change) + goto done; + + return failover_ops->slave_link_change(slave_dev, failover_dev); + } + + if (!netif_running(failover_dev)) + return 0; + + finfo = netdev_priv(failover_dev); + + primary_dev = rtnl_dereference(finfo->primary_dev); + standby_dev = rtnl_dereference(finfo->standby_dev); + + if (slave_dev != primary_dev && slave_dev != standby_dev) + goto done; + + if ((primary_dev && failover_xmit_ready(primary_dev)) || + (standby_dev && failover_xmit_ready(standby_dev))) { + netif_carrier_on(failover_dev); + netif_tx_wake_all_queues(failover_dev); + } else { + netif_carrier_off(failover_dev); + netif_tx_stop_all_queues(failover_dev); + } + +done: + return NOTIFY_DONE; +} + +static bool failover_validate_event_dev(struct net_device *dev) +{ + /* Skip parent events */ + if (netif_is_failover(dev)) + return false; + + /* Avoid non-Ethernet type devices */ + if (dev->type != ARPHRD_ETHER) + return false; + + return true; +} + +static int +failover_event(struct notifier_block *this, unsigned long event, void *ptr) +{ + struct net_device *event_dev = netdev_notifier_info_to_dev(ptr); + + if (!failover_validate_event_dev(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); + default: + return NOTIFY_DONE; + } +} + +static struct notifier_block failover_notifier = { + .notifier_call = failover_event, +}; + +static int failover_open(struct net_device *dev) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *primary_dev, *standby_dev; + int err; + + netif_carrier_off(dev); + netif_tx_wake_all_queues(dev); + + primary_dev = rtnl_dereference(finfo->primary_dev); + if (primary_dev) { + err = dev_open(primary_dev); + if (err) + goto err_primary_open; + } + + standby_dev = rtnl_dereference(finfo->standby_dev); + if (standby_dev) { + err = dev_open(standby_dev); + if (err) + goto err_standby_open; + } + + return 0; + +err_standby_open: + dev_close(primary_dev); +err_primary_open: + netif_tx_disable(dev); + return err; +} + +static int failover_close(struct net_device *dev) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *slave_dev; + + netif_tx_disable(dev); + + slave_dev = rtnl_dereference(finfo->primary_dev); + if (slave_dev) + dev_close(slave_dev); + + slave_dev = rtnl_dereference(finfo->standby_dev); + if (slave_dev) + dev_close(slave_dev); + + return 0; +} + +static netdev_tx_t failover_drop_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + atomic_long_inc(&dev->tx_dropped); + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; +} + +static netdev_tx_t failover_start_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *xmit_dev; + + /* Try xmit via primary netdev followed by standby netdev */ + xmit_dev = rcu_dereference_bh(finfo->primary_dev); + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) { + xmit_dev = rcu_dereference_bh(finfo->standby_dev); + if (!xmit_dev || !failover_xmit_ready(xmit_dev)) + return failover_drop_xmit(skb, dev); + } + + skb->dev = xmit_dev; + skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping; + + return dev_queue_xmit(skb); +} + +static u16 failover_select_queue(struct net_device *dev, struct sk_buff *skb, + void *accel_priv, + select_queue_fallback_t fallback) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *primary_dev; + u16 txq; + + rcu_read_lock(); + primary_dev = rcu_dereference(finfo->primary_dev); + if (primary_dev) { + const struct net_device_ops *ops = primary_dev->netdev_ops; + + if (ops->ndo_select_queue) + txq = ops->ndo_select_queue(primary_dev, skb, + accel_priv, fallback); + else + txq = fallback(primary_dev, skb); + + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; + + return txq; + } + + txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0; + + /* Save the original txq to restore before passing to the driver */ + qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping; + + if (unlikely(txq >= dev->real_num_tx_queues)) { + do { + txq -= dev->real_num_tx_queues; + } while (txq >= dev->real_num_tx_queues); + } + + return txq; +} + +/* fold stats, assuming all rtnl_link_stats64 fields are u64, but + * that some drivers can provide 32finfot values only. + */ +static void failover_fold_stats(struct rtnl_link_stats64 *_res, + const struct rtnl_link_stats64 *_new, + const struct rtnl_link_stats64 *_old) +{ + const u64 *new = (const u64 *)_new; + const u64 *old = (const u64 *)_old; + u64 *res = (u64 *)_res; + int i; + + for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) { + u64 nv = new[i]; + u64 ov = old[i]; + s64 delta = nv - ov; + + /* detects if this particular field is 32bit only */ + if (((nv | ov) >> 32) == 0) + delta = (s64)(s32)((u32)nv - (u32)ov); + + /* filter anomalies, some drivers reset their stats + * at down/up events. + */ + if (delta > 0) + res[i] += delta; + } +} + +static void failover_get_stats(struct net_device *dev, + struct rtnl_link_stats64 *stats) +{ + struct failover_info *finfo = netdev_priv(dev); + const struct rtnl_link_stats64 *new; + struct rtnl_link_stats64 temp; + struct net_device *slave_dev; + + spin_lock(&finfo->stats_lock); + memcpy(stats, &finfo->failover_stats, sizeof(*stats)); + + rcu_read_lock(); + + slave_dev = rcu_dereference(finfo->primary_dev); + if (slave_dev) { + new = dev_get_stats(slave_dev, &temp); + failover_fold_stats(stats, new, &finfo->primary_stats); + memcpy(&finfo->primary_stats, new, sizeof(*new)); + } + + slave_dev = rcu_dereference(finfo->standby_dev); + if (slave_dev) { + new = dev_get_stats(slave_dev, &temp); + failover_fold_stats(stats, new, &finfo->standby_stats); + memcpy(&finfo->standby_stats, new, sizeof(*new)); + } + + rcu_read_unlock(); + + memcpy(&finfo->failover_stats, stats, sizeof(*stats)); + spin_unlock(&finfo->stats_lock); +} + +static int failover_change_mtu(struct net_device *dev, int new_mtu) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *primary_dev, *standby_dev; + int ret = 0; + + primary_dev = rcu_dereference(finfo->primary_dev); + if (primary_dev) { + ret = dev_set_mtu(primary_dev, new_mtu); + if (ret) + return ret; + } + + standby_dev = rcu_dereference(finfo->standby_dev); + if (standby_dev) { + ret = dev_set_mtu(standby_dev, new_mtu); + if (ret) { + dev_set_mtu(primary_dev, dev->mtu); + return ret; + } + } + + dev->mtu = new_mtu; + return 0; +} + +static void failover_set_rx_mode(struct net_device *dev) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *slave_dev; + + rcu_read_lock(); + + slave_dev = rcu_dereference(finfo->primary_dev); + if (slave_dev) { + dev_uc_sync_multiple(slave_dev, dev); + dev_mc_sync_multiple(slave_dev, dev); + } + + slave_dev = rcu_dereference(finfo->standby_dev); + if (slave_dev) { + dev_uc_sync_multiple(slave_dev, dev); + dev_mc_sync_multiple(slave_dev, dev); + } + + rcu_read_unlock(); +} + +static const struct net_device_ops failover_dev_ops = { + .ndo_open = failover_open, + .ndo_stop = failover_close, + .ndo_start_xmit = failover_start_xmit, + .ndo_select_queue = failover_select_queue, + .ndo_get_stats64 = failover_get_stats, + .ndo_change_mtu = failover_change_mtu, + .ndo_set_rx_mode = failover_set_rx_mode, + .ndo_validate_addr = eth_validate_addr, + .ndo_features_check = passthru_features_check, +}; + +#define FAILOVER_NAME "failover" +#define FAILOVER_VERSION "0.1" + +static void failover_ethtool_get_drvinfo(struct net_device *dev, + struct ethtool_drvinfo *drvinfo) +{ + strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver)); + strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version)); +} + +int failover_ethtool_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *cmd) +{ + struct failover_info *finfo = netdev_priv(dev); + struct net_device *slave_dev; + + slave_dev = rtnl_dereference(finfo->primary_dev); + if (!slave_dev || !failover_xmit_ready(slave_dev)) { + slave_dev = rtnl_dereference(finfo->standby_dev); + if (!slave_dev || !failover_xmit_ready(slave_dev)) { + cmd->base.duplex = DUPLEX_UNKNOWN; + cmd->base.port = PORT_OTHER; + cmd->base.speed = SPEED_UNKNOWN; + + return 0; + } + } + + return __ethtool_get_link_ksettings(slave_dev, cmd); +} +EXPORT_SYMBOL_GPL(failover_ethtool_get_link_ksettings); + +static const struct ethtool_ops failover_ethtool_ops = { + .get_drvinfo = failover_ethtool_get_drvinfo, + .get_link = ethtool_op_get_link, + .get_link_ksettings = failover_ethtool_get_link_ksettings, +}; + +static void failover_register_existing_slave(struct net_device *failover_dev) +{ + struct net *net = dev_net(failover_dev); + struct net_device *dev; + + rtnl_lock(); + for_each_netdev(net, dev) { + if (dev == failover_dev) + continue; + if (!failover_validate_event_dev(dev)) + continue; + if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr)) + failover_slave_register(dev); + } + rtnl_unlock(); +} + +int failover_register(struct net_device *dev, struct failover_ops *ops, + struct failover **pfailover) +{ + struct failover *failover; + + failover = kzalloc(sizeof(*failover), GFP_KERNEL); + if (!failover) + return -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); + + failover_register_existing_slave(dev); + + *pfailover = failover; + return 0; +} +EXPORT_SYMBOL_GPL(failover_register); + +void failover_unregister(struct failover *failover) +{ + struct net_device *failover_dev; + + failover_dev = rcu_dereference(failover->failover_dev); + + 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); + +int failover_create(struct net_device *standby_dev, struct failover **pfailover) +{ + struct device *dev = standby_dev->dev.parent; + struct net_device *failover_dev; + int err; + + /* Alloc at least 2 queues, for now we are going with 16 assuming + * that most devices being bonded won't have too many queues. + */ + failover_dev = alloc_etherdev_mq(sizeof(struct failover_info), 16); + if (!failover_dev) { + dev_err(dev, "Unable to allocate failover_netdev!\n"); + return -ENOMEM; + } + + dev_net_set(failover_dev, dev_net(standby_dev)); + SET_NETDEV_DEV(failover_dev, dev); + + failover_dev->netdev_ops = &failover_dev_ops; + failover_dev->ethtool_ops = &failover_ethtool_ops; + + /* Initialize the device options */ + failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE; + failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | + IFF_TX_SKB_SHARING); + + /* don't acquire failover netdev's netif_tx_lock when transmitting */ + failover_dev->features |= NETIF_F_LLTX; + + /* Don't allow failover devices to change network namespaces. */ + failover_dev->features |= NETIF_F_NETNS_LOCAL; + + failover_dev->hw_features = NETIF_F_HW_CSUM | NETIF_F_SG | + NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | + NETIF_F_HIGHDMA | NETIF_F_LRO; + + failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL; + failover_dev->features |= failover_dev->hw_features; + + memcpy(failover_dev->dev_addr, standby_dev->dev_addr, + failover_dev->addr_len); + + failover_dev->min_mtu = standby_dev->min_mtu; + failover_dev->max_mtu = standby_dev->max_mtu; + + err = register_netdev(failover_dev); + if (err < 0) { + dev_err(dev, "Unable to register failover_dev!\n"); + goto err_register_netdev; + } + + netif_carrier_off(failover_dev); + + err = failover_register(failover_dev, NULL, pfailover); + if (err < 0) + goto err_failover; + + return 0; + +err_failover: + unregister_netdev(failover_dev); +err_register_netdev: + free_netdev(failover_dev); + + return err; +} +EXPORT_SYMBOL_GPL(failover_create); + +void failover_destroy(struct failover *failover) +{ + struct net_device *failover_dev; + struct net_device *slave_dev; + struct failover_info *finfo; + + if (!failover) + return; + + failover_dev = rcu_dereference(failover->failover_dev); + finfo = netdev_priv(failover_dev); + + netif_device_detach(failover_dev); + + rtnl_lock(); + + slave_dev = rtnl_dereference(finfo->primary_dev); + if (slave_dev) + failover_slave_unregister(slave_dev); + + slave_dev = rtnl_dereference(finfo->standby_dev); + if (slave_dev) + failover_slave_unregister(slave_dev); + + failover_unregister(failover); + + unregister_netdevice(failover_dev); + + rtnl_unlock(); + + free_netdev(failover_dev); +} +EXPORT_SYMBOL_GPL(failover_destroy); + +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("Failover infrastructure/interface for Paravirtual drivers"); +MODULE_LICENSE("GPL v2");
This provides a generic interface for paravirtual drivers to listen for netdev register/unregister/link change events from pci ethernet devices with the same MAC and takeover their datapath. The notifier and event handling code is based on the existing netvsc implementation. It exposes 2 sets of interfaces to the paravirtual drivers. 1. existing netvsc driver that uses 2 netdev model. In this model, no master netdev is created. The paravirtual driver registers each instance of netvsc as a 'failover' instance along with a set of ops to manage the slave events. failover_register() failover_unregister() 2. new virtio_net based solution that uses 3 netdev model. In this model, the failover module provides interfaces to create/destroy additional master netdev and all the slave events are managed internally. failover_create() failover_destroy() These functions call failover_register()/failover_unregister() with the master netdev created by the failover module. Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com> --- include/linux/netdevice.h | 16 + include/net/failover.h | 96 ++++++ net/Kconfig | 18 + net/core/Makefile | 1 + net/core/failover.c | 844 ++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 975 insertions(+) create mode 100644 include/net/failover.h create mode 100644 net/core/failover.c