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![David S. Miller](/assets/img/avatar_default.png)
Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller <davem@davemloft.net>
310 lines
7.7 KiB
C
310 lines
7.7 KiB
C
/*
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* Copyright (c) 2007-2012 Nicira, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#include <linux/hardirq.h>
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#include <linux/if_vlan.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/ethtool.h>
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#include <linux/skbuff.h>
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#include <net/dst.h>
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#include <net/xfrm.h>
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#include <net/rtnetlink.h>
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#include "datapath.h"
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#include "vport-internal_dev.h"
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#include "vport-netdev.h"
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struct internal_dev {
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struct vport *vport;
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};
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static struct vport_ops ovs_internal_vport_ops;
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static struct internal_dev *internal_dev_priv(struct net_device *netdev)
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{
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return netdev_priv(netdev);
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}
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/* Called with rcu_read_lock_bh. */
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static int internal_dev_xmit(struct sk_buff *skb, struct net_device *netdev)
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{
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int len, err;
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len = skb->len;
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rcu_read_lock();
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err = ovs_vport_receive(internal_dev_priv(netdev)->vport, skb, NULL);
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rcu_read_unlock();
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if (likely(!err)) {
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struct pcpu_sw_netstats *tstats = this_cpu_ptr(netdev->tstats);
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u64_stats_update_begin(&tstats->syncp);
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tstats->tx_bytes += len;
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tstats->tx_packets++;
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u64_stats_update_end(&tstats->syncp);
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} else {
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netdev->stats.tx_errors++;
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}
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return 0;
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}
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static int internal_dev_open(struct net_device *netdev)
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{
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netif_start_queue(netdev);
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return 0;
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}
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static int internal_dev_stop(struct net_device *netdev)
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{
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netif_stop_queue(netdev);
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return 0;
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}
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static void internal_dev_getinfo(struct net_device *netdev,
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struct ethtool_drvinfo *info)
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{
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strlcpy(info->driver, "openvswitch", sizeof(info->driver));
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}
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static const struct ethtool_ops internal_dev_ethtool_ops = {
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.get_drvinfo = internal_dev_getinfo,
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.get_link = ethtool_op_get_link,
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};
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static void internal_dev_destructor(struct net_device *dev)
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{
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struct vport *vport = ovs_internal_dev_get_vport(dev);
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ovs_vport_free(vport);
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}
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static void
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internal_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats)
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{
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int i;
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memset(stats, 0, sizeof(*stats));
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stats->rx_errors = dev->stats.rx_errors;
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stats->tx_errors = dev->stats.tx_errors;
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stats->tx_dropped = dev->stats.tx_dropped;
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stats->rx_dropped = dev->stats.rx_dropped;
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for_each_possible_cpu(i) {
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const struct pcpu_sw_netstats *percpu_stats;
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struct pcpu_sw_netstats local_stats;
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unsigned int start;
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percpu_stats = per_cpu_ptr(dev->tstats, i);
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do {
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start = u64_stats_fetch_begin_irq(&percpu_stats->syncp);
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local_stats = *percpu_stats;
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} while (u64_stats_fetch_retry_irq(&percpu_stats->syncp, start));
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stats->rx_bytes += local_stats.rx_bytes;
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stats->rx_packets += local_stats.rx_packets;
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stats->tx_bytes += local_stats.tx_bytes;
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stats->tx_packets += local_stats.tx_packets;
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}
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}
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static void internal_set_rx_headroom(struct net_device *dev, int new_hr)
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{
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dev->needed_headroom = new_hr < 0 ? 0 : new_hr;
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}
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static const struct net_device_ops internal_dev_netdev_ops = {
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.ndo_open = internal_dev_open,
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.ndo_stop = internal_dev_stop,
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.ndo_start_xmit = internal_dev_xmit,
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.ndo_set_mac_address = eth_mac_addr,
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.ndo_get_stats64 = internal_get_stats,
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.ndo_set_rx_headroom = internal_set_rx_headroom,
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};
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static struct rtnl_link_ops internal_dev_link_ops __read_mostly = {
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.kind = "openvswitch",
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};
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static void do_setup(struct net_device *netdev)
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{
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ether_setup(netdev);
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netdev->max_mtu = ETH_MAX_MTU;
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netdev->netdev_ops = &internal_dev_netdev_ops;
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netdev->priv_flags &= ~IFF_TX_SKB_SHARING;
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netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_OPENVSWITCH |
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IFF_PHONY_HEADROOM | IFF_NO_QUEUE;
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netdev->needs_free_netdev = true;
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netdev->priv_destructor = internal_dev_destructor;
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netdev->ethtool_ops = &internal_dev_ethtool_ops;
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netdev->rtnl_link_ops = &internal_dev_link_ops;
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netdev->features = NETIF_F_LLTX | NETIF_F_SG | NETIF_F_FRAGLIST |
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NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
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NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL;
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netdev->vlan_features = netdev->features;
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netdev->hw_enc_features = netdev->features;
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netdev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
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netdev->hw_features = netdev->features & ~NETIF_F_LLTX;
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eth_hw_addr_random(netdev);
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}
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static struct vport *internal_dev_create(const struct vport_parms *parms)
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{
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struct vport *vport;
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struct internal_dev *internal_dev;
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int err;
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vport = ovs_vport_alloc(0, &ovs_internal_vport_ops, parms);
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if (IS_ERR(vport)) {
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err = PTR_ERR(vport);
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goto error;
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}
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vport->dev = alloc_netdev(sizeof(struct internal_dev),
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parms->name, NET_NAME_USER, do_setup);
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if (!vport->dev) {
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err = -ENOMEM;
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goto error_free_vport;
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}
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vport->dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
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if (!vport->dev->tstats) {
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err = -ENOMEM;
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goto error_free_netdev;
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}
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vport->dev->needed_headroom = vport->dp->max_headroom;
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dev_net_set(vport->dev, ovs_dp_get_net(vport->dp));
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internal_dev = internal_dev_priv(vport->dev);
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internal_dev->vport = vport;
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/* Restrict bridge port to current netns. */
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if (vport->port_no == OVSP_LOCAL)
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vport->dev->features |= NETIF_F_NETNS_LOCAL;
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rtnl_lock();
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err = register_netdevice(vport->dev);
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if (err)
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goto error_unlock;
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dev_set_promiscuity(vport->dev, 1);
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rtnl_unlock();
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netif_start_queue(vport->dev);
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return vport;
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error_unlock:
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rtnl_unlock();
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free_percpu(vport->dev->tstats);
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error_free_netdev:
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free_netdev(vport->dev);
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error_free_vport:
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ovs_vport_free(vport);
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error:
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return ERR_PTR(err);
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}
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static void internal_dev_destroy(struct vport *vport)
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{
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netif_stop_queue(vport->dev);
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rtnl_lock();
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dev_set_promiscuity(vport->dev, -1);
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/* unregister_netdevice() waits for an RCU grace period. */
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unregister_netdevice(vport->dev);
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free_percpu(vport->dev->tstats);
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rtnl_unlock();
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}
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static netdev_tx_t internal_dev_recv(struct sk_buff *skb)
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{
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struct net_device *netdev = skb->dev;
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struct pcpu_sw_netstats *stats;
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if (unlikely(!(netdev->flags & IFF_UP))) {
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kfree_skb(skb);
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netdev->stats.rx_dropped++;
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return NETDEV_TX_OK;
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}
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skb_dst_drop(skb);
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nf_reset(skb);
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secpath_reset(skb);
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skb->pkt_type = PACKET_HOST;
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skb->protocol = eth_type_trans(skb, netdev);
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skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
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stats = this_cpu_ptr(netdev->tstats);
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u64_stats_update_begin(&stats->syncp);
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stats->rx_packets++;
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stats->rx_bytes += skb->len;
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u64_stats_update_end(&stats->syncp);
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netif_rx(skb);
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return NETDEV_TX_OK;
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}
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static struct vport_ops ovs_internal_vport_ops = {
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.type = OVS_VPORT_TYPE_INTERNAL,
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.create = internal_dev_create,
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.destroy = internal_dev_destroy,
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.send = internal_dev_recv,
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};
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int ovs_is_internal_dev(const struct net_device *netdev)
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{
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return netdev->netdev_ops == &internal_dev_netdev_ops;
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}
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struct vport *ovs_internal_dev_get_vport(struct net_device *netdev)
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{
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if (!ovs_is_internal_dev(netdev))
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return NULL;
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return internal_dev_priv(netdev)->vport;
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}
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int ovs_internal_dev_rtnl_link_register(void)
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{
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int err;
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err = rtnl_link_register(&internal_dev_link_ops);
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if (err < 0)
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return err;
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err = ovs_vport_ops_register(&ovs_internal_vport_ops);
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if (err < 0)
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rtnl_link_unregister(&internal_dev_link_ops);
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return err;
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}
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void ovs_internal_dev_rtnl_link_unregister(void)
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{
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ovs_vport_ops_unregister(&ovs_internal_vport_ops);
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rtnl_link_unregister(&internal_dev_link_ops);
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}
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