kernel-ark/drivers/net/ifb.c
Jarek Poplawski 94833dfb8c [NET] ifb: set separate lockdep classes for queue locks
[   10.536424] =======================================================
[   10.536424] [ INFO: possible circular locking dependency detected ]
[   10.536424] 2.6.25-rc3-devel #3
[   10.536424] -------------------------------------------------------
[   10.536424] swapper/0 is trying to acquire lock:
[   10.536424]  (&dev->queue_lock){-+..}, at: [<c0299b4a>] 
dev_queue_xmit+0x175/0x2f3
[   10.536424]
[   10.536424] but task is already holding lock:
[   10.536424]  (&p->tcfc_lock){-+..}, at: [<f8a67154>] tcf_mirred+0x20/0x178 
[act_mirred]
[   10.536424]
[   10.536424] which lock already depends on the new lock.

lockdep warns of locking order while using ifb with sch_ingress and
act_mirred: ingress_lock, tcfc_lock, queue_lock (usually queue_lock
is at the beginning). This patch is only to tell lockdep that ifb is
a different device (e.g. from eth) and has its own pair of queue
locks. (This warning is a false-positive in common scenario of using
ifb; yet there are possible situations, when this order could be
dangerous; lockdep should warn in such a case.) (With suggestions by
David S. Miller)

Reported-and-tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-20 17:05:13 -07:00

297 lines
7.1 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/moduleparam.h>
#include <net/pkt_sched.h>
#include <net/net_namespace.h>
#include <linux/lockdep.h>
#define TX_TIMEOUT (2*HZ)
#define TX_Q_LIMIT 32
struct ifb_private {
struct tasklet_struct ifb_tasklet;
int tasklet_pending;
/* mostly debug stats leave in for now */
unsigned long st_task_enter; /* tasklet entered */
unsigned long st_txq_refl_try; /* transmit queue refill attempt */
unsigned long st_rxq_enter; /* receive queue entered */
unsigned long st_rx2tx_tran; /* receive to trasmit transfers */
unsigned long st_rxq_notenter; /*receiveQ not entered, resched */
unsigned long st_rx_frm_egr; /* received from egress path */
unsigned long st_rx_frm_ing; /* received from ingress path */
unsigned long st_rxq_check;
unsigned long st_rxq_rsch;
struct sk_buff_head rq;
struct sk_buff_head tq;
};
static int numifbs = 2;
static void ri_tasklet(unsigned long dev);
static int 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 ri_tasklet(unsigned long dev)
{
struct net_device *_dev = (struct net_device *)dev;
struct ifb_private *dp = netdev_priv(_dev);
struct net_device_stats *stats = &_dev->stats;
struct sk_buff *skb;
dp->st_task_enter++;
if ((skb = skb_peek(&dp->tq)) == NULL) {
dp->st_txq_refl_try++;
if (netif_tx_trylock(_dev)) {
dp->st_rxq_enter++;
while ((skb = skb_dequeue(&dp->rq)) != NULL) {
skb_queue_tail(&dp->tq, skb);
dp->st_rx2tx_tran++;
}
netif_tx_unlock(_dev);
} else {
/* reschedule */
dp->st_rxq_notenter++;
goto resched;
}
}
while ((skb = skb_dequeue(&dp->tq)) != NULL) {
u32 from = G_TC_FROM(skb->tc_verd);
skb->tc_verd = 0;
skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
stats->tx_packets++;
stats->tx_bytes +=skb->len;
skb->dev = __dev_get_by_index(&init_net, skb->iif);
if (!skb->dev) {
dev_kfree_skb(skb);
stats->tx_dropped++;
break;
}
skb->iif = _dev->ifindex;
if (from & AT_EGRESS) {
dp->st_rx_frm_egr++;
dev_queue_xmit(skb);
} else if (from & AT_INGRESS) {
dp->st_rx_frm_ing++;
skb_pull(skb, skb->dev->hard_header_len);
netif_rx(skb);
} else
BUG();
}
if (netif_tx_trylock(_dev)) {
dp->st_rxq_check++;
if ((skb = skb_peek(&dp->rq)) == NULL) {
dp->tasklet_pending = 0;
if (netif_queue_stopped(_dev))
netif_wake_queue(_dev);
} else {
dp->st_rxq_rsch++;
netif_tx_unlock(_dev);
goto resched;
}
netif_tx_unlock(_dev);
} else {
resched:
dp->tasklet_pending = 1;
tasklet_schedule(&dp->ifb_tasklet);
}
}
static void ifb_setup(struct net_device *dev)
{
/* Initialize the device structure. */
dev->hard_start_xmit = ifb_xmit;
dev->open = &ifb_open;
dev->stop = &ifb_close;
dev->destructor = free_netdev;
/* Fill in device structure with ethernet-generic values. */
ether_setup(dev);
dev->tx_queue_len = TX_Q_LIMIT;
dev->change_mtu = NULL;
dev->flags |= IFF_NOARP;
dev->flags &= ~IFF_MULTICAST;
random_ether_addr(dev->dev_addr);
}
static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ifb_private *dp = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
int ret = 0;
u32 from = G_TC_FROM(skb->tc_verd);
stats->rx_packets++;
stats->rx_bytes+=skb->len;
if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
dev_kfree_skb(skb);
stats->rx_dropped++;
return ret;
}
if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
netif_stop_queue(dev);
}
dev->trans_start = jiffies;
skb_queue_tail(&dp->rq, skb);
if (!dp->tasklet_pending) {
dp->tasklet_pending = 1;
tasklet_schedule(&dp->ifb_tasklet);
}
return ret;
}
static int ifb_close(struct net_device *dev)
{
struct ifb_private *dp = netdev_priv(dev);
tasklet_kill(&dp->ifb_tasklet);
netif_stop_queue(dev);
skb_queue_purge(&dp->rq);
skb_queue_purge(&dp->tq);
return 0;
}
static int ifb_open(struct net_device *dev)
{
struct ifb_private *dp = netdev_priv(dev);
tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
skb_queue_head_init(&dp->rq);
skb_queue_head_init(&dp->tq);
netif_start_queue(dev);
return 0;
}
static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
{
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_private),
.setup = ifb_setup,
.validate = ifb_validate,
};
/* Number of ifb devices to be set up by this module. */
module_param(numifbs, int, 0);
MODULE_PARM_DESC(numifbs, "Number of ifb devices");
/*
* dev_ifb->queue_lock is usually taken after dev->ingress_lock,
* reversely to e.g. qdisc_lock_tree(). It should be safe until
* ifb doesn't take dev->queue_lock with dev_ifb->ingress_lock.
* But lockdep should know that ifb has different locks from dev.
*/
static struct lock_class_key ifb_queue_lock_key;
static struct lock_class_key ifb_ingress_lock_key;
static int __init ifb_init_one(int index)
{
struct net_device *dev_ifb;
int err;
dev_ifb = alloc_netdev(sizeof(struct ifb_private),
"ifb%d", ifb_setup);
if (!dev_ifb)
return -ENOMEM;
err = dev_alloc_name(dev_ifb, dev_ifb->name);
if (err < 0)
goto err;
dev_ifb->rtnl_link_ops = &ifb_link_ops;
err = register_netdevice(dev_ifb);
if (err < 0)
goto err;
lockdep_set_class(&dev_ifb->queue_lock, &ifb_queue_lock_key);
lockdep_set_class(&dev_ifb->ingress_lock, &ifb_ingress_lock_key);
return 0;
err:
free_netdev(dev_ifb);
return err;
}
static int __init ifb_init_module(void)
{
int i, err;
rtnl_lock();
err = __rtnl_link_register(&ifb_link_ops);
for (i = 0; i < numifbs && !err; i++)
err = ifb_init_one(i);
if (err)
__rtnl_link_unregister(&ifb_link_ops);
rtnl_unlock();
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");