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Subject: [PATCH v7 net-next 2/4] net: Introduce generic failover module
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
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");
--
2.14.3
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