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linux-next/drivers/net/ifb.c
Kirill Tkhai 554873e517 net: Do not take net_rwsem in __rtnl_link_unregister()
This function calls call_netdevice_notifier(), which also
may take net_rwsem. So, we can't use net_rwsem here.

This patch makes callers of this functions take pernet_ops_rwsem,
like register_netdevice_notifier() does. This will protect
the modifications of net_namespace_list, and allows notifiers
to take it (they won't have to care about context).

Since __rtnl_link_unregister() is used on module load
and unload (which are not frequent operations), this looks
for me better, than make all call_netdevice_notifier()
always executing in "protected net_namespace_list" context.

Also, this fixes the problem we had a deal in 328fbe747a
"Close race between {un, }register_netdevice_notifier and ...",
and guarantees __rtnl_link_unregister() does not skip
exitting net.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-31 22:24:58 -04:00

363 lines
8.6 KiB
C

/* drivers/net/ifb.c:
The purpose of this driver is to provide a device that allows
for sharing of resources:
1) qdiscs/policies that are per device as opposed to system wide.
ifb allows for a device which can be redirected to thus providing
an impression of sharing.
2) Allows for queueing incoming traffic for shaping instead of
dropping.
The original concept is based on what is known as the IMQ
driver initially written by Martin Devera, later rewritten
by Patrick McHardy and then maintained by Andre Correa.
You need the tc action mirror or redirect to feed this device
packets.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version
2 of the License, or (at your option) any later version.
Authors: Jamal Hadi Salim (2005)
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <net/pkt_sched.h>
#include <net/net_namespace.h>
#define TX_Q_LIMIT 32
struct ifb_q_private {
struct net_device *dev;
struct tasklet_struct ifb_tasklet;
int tasklet_pending;
int txqnum;
struct sk_buff_head rq;
u64 rx_packets;
u64 rx_bytes;
struct u64_stats_sync rsync;
struct u64_stats_sync tsync;
u64 tx_packets;
u64 tx_bytes;
struct sk_buff_head tq;
} ____cacheline_aligned_in_smp;
struct ifb_dev_private {
struct ifb_q_private *tx_private;
};
static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
static int ifb_open(struct net_device *dev);
static int ifb_close(struct net_device *dev);
static void ifb_ri_tasklet(unsigned long _txp)
{
struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
struct netdev_queue *txq;
struct sk_buff *skb;
txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
skb = skb_peek(&txp->tq);
if (!skb) {
if (!__netif_tx_trylock(txq))
goto resched;
skb_queue_splice_tail_init(&txp->rq, &txp->tq);
__netif_tx_unlock(txq);
}
while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
skb->tc_redirected = 0;
skb->tc_skip_classify = 1;
u64_stats_update_begin(&txp->tsync);
txp->tx_packets++;
txp->tx_bytes += skb->len;
u64_stats_update_end(&txp->tsync);
rcu_read_lock();
skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
if (!skb->dev) {
rcu_read_unlock();
dev_kfree_skb(skb);
txp->dev->stats.tx_dropped++;
if (skb_queue_len(&txp->tq) != 0)
goto resched;
break;
}
rcu_read_unlock();
skb->skb_iif = txp->dev->ifindex;
if (!skb->tc_from_ingress) {
dev_queue_xmit(skb);
} else {
skb_pull(skb, skb->mac_len);
netif_receive_skb(skb);
}
}
if (__netif_tx_trylock(txq)) {
skb = skb_peek(&txp->rq);
if (!skb) {
txp->tasklet_pending = 0;
if (netif_tx_queue_stopped(txq))
netif_tx_wake_queue(txq);
} else {
__netif_tx_unlock(txq);
goto resched;
}
__netif_tx_unlock(txq);
} else {
resched:
txp->tasklet_pending = 1;
tasklet_schedule(&txp->ifb_tasklet);
}
}
static void ifb_stats64(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp = dp->tx_private;
unsigned int start;
u64 packets, bytes;
int i;
for (i = 0; i < dev->num_tx_queues; i++,txp++) {
do {
start = u64_stats_fetch_begin_irq(&txp->rsync);
packets = txp->rx_packets;
bytes = txp->rx_bytes;
} while (u64_stats_fetch_retry_irq(&txp->rsync, start));
stats->rx_packets += packets;
stats->rx_bytes += bytes;
do {
start = u64_stats_fetch_begin_irq(&txp->tsync);
packets = txp->tx_packets;
bytes = txp->tx_bytes;
} while (u64_stats_fetch_retry_irq(&txp->tsync, start));
stats->tx_packets += packets;
stats->tx_bytes += bytes;
}
stats->rx_dropped = dev->stats.rx_dropped;
stats->tx_dropped = dev->stats.tx_dropped;
}
static int ifb_dev_init(struct net_device *dev)
{
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp;
int i;
txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
if (!txp)
return -ENOMEM;
dp->tx_private = txp;
for (i = 0; i < dev->num_tx_queues; i++,txp++) {
txp->txqnum = i;
txp->dev = dev;
__skb_queue_head_init(&txp->rq);
__skb_queue_head_init(&txp->tq);
u64_stats_init(&txp->rsync);
u64_stats_init(&txp->tsync);
tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
(unsigned long)txp);
netif_tx_start_queue(netdev_get_tx_queue(dev, i));
}
return 0;
}
static const struct net_device_ops ifb_netdev_ops = {
.ndo_open = ifb_open,
.ndo_stop = ifb_close,
.ndo_get_stats64 = ifb_stats64,
.ndo_start_xmit = ifb_xmit,
.ndo_validate_addr = eth_validate_addr,
.ndo_init = ifb_dev_init,
};
#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \
NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \
NETIF_F_GSO_ENCAP_ALL | \
NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
NETIF_F_HW_VLAN_STAG_TX)
static void ifb_dev_free(struct net_device *dev)
{
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp = dp->tx_private;
int i;
for (i = 0; i < dev->num_tx_queues; i++,txp++) {
tasklet_kill(&txp->ifb_tasklet);
__skb_queue_purge(&txp->rq);
__skb_queue_purge(&txp->tq);
}
kfree(dp->tx_private);
}
static void ifb_setup(struct net_device *dev)
{
/* Initialize the device structure. */
dev->netdev_ops = &ifb_netdev_ops;
/* Fill in device structure with ethernet-generic values. */
ether_setup(dev);
dev->tx_queue_len = TX_Q_LIMIT;
dev->features |= IFB_FEATURES;
dev->hw_features |= dev->features;
dev->hw_enc_features |= dev->features;
dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_STAG_TX);
dev->flags |= IFF_NOARP;
dev->flags &= ~IFF_MULTICAST;
dev->priv_flags &= ~IFF_TX_SKB_SHARING;
netif_keep_dst(dev);
eth_hw_addr_random(dev);
dev->needs_free_netdev = true;
dev->priv_destructor = ifb_dev_free;
dev->min_mtu = 0;
dev->max_mtu = 0;
}
static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ifb_dev_private *dp = netdev_priv(dev);
struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
u64_stats_update_begin(&txp->rsync);
txp->rx_packets++;
txp->rx_bytes += skb->len;
u64_stats_update_end(&txp->rsync);
if (!skb->tc_redirected || !skb->skb_iif) {
dev_kfree_skb(skb);
dev->stats.rx_dropped++;
return NETDEV_TX_OK;
}
if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
__skb_queue_tail(&txp->rq, skb);
if (!txp->tasklet_pending) {
txp->tasklet_pending = 1;
tasklet_schedule(&txp->ifb_tasklet);
}
return NETDEV_TX_OK;
}
static int ifb_close(struct net_device *dev)
{
netif_tx_stop_all_queues(dev);
return 0;
}
static int ifb_open(struct net_device *dev)
{
netif_tx_start_all_queues(dev);
return 0;
}
static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
return -EINVAL;
if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
return -EADDRNOTAVAIL;
}
return 0;
}
static struct rtnl_link_ops ifb_link_ops __read_mostly = {
.kind = "ifb",
.priv_size = sizeof(struct ifb_dev_private),
.setup = ifb_setup,
.validate = ifb_validate,
};
/* Number of ifb devices to be set up by this module.
* Note that these legacy devices have one queue.
* Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
*/
static int numifbs = 2;
module_param(numifbs, int, 0);
MODULE_PARM_DESC(numifbs, "Number of ifb devices");
static int __init ifb_init_one(int index)
{
struct net_device *dev_ifb;
int err;
dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
NET_NAME_UNKNOWN, ifb_setup);
if (!dev_ifb)
return -ENOMEM;
dev_ifb->rtnl_link_ops = &ifb_link_ops;
err = register_netdevice(dev_ifb);
if (err < 0)
goto err;
return 0;
err:
free_netdev(dev_ifb);
return err;
}
static int __init ifb_init_module(void)
{
int i, err;
down_write(&pernet_ops_rwsem);
rtnl_lock();
err = __rtnl_link_register(&ifb_link_ops);
if (err < 0)
goto out;
for (i = 0; i < numifbs && !err; i++) {
err = ifb_init_one(i);
cond_resched();
}
if (err)
__rtnl_link_unregister(&ifb_link_ops);
out:
rtnl_unlock();
up_write(&pernet_ops_rwsem);
return err;
}
static void __exit ifb_cleanup_module(void)
{
rtnl_link_unregister(&ifb_link_ops);
}
module_init(ifb_init_module);
module_exit(ifb_cleanup_module);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamal Hadi Salim");
MODULE_ALIAS_RTNL_LINK("ifb");