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![Jarek Poplawski](/assets/img/avatar_default.png)
Use qdisc_root_sleeping_lock() instead of qdisc_root_lock() where appropriate. The only difference is while dev is deactivated, when currently we can use a sleeping qdisc with the lock of noop_qdisc. This shouldn't be dangerous since after deactivation root lock could be used only by gen_estimator code, but looks wrong anyway. Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
513 lines
12 KiB
C
513 lines
12 KiB
C
/* net/sched/sch_teql.c "True" (or "trivial") link equalizer.
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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 the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/if_arp.h>
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#include <linux/netdevice.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/moduleparam.h>
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#include <net/dst.h>
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#include <net/neighbour.h>
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#include <net/pkt_sched.h>
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/*
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How to setup it.
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----------------
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After loading this module you will find a new device teqlN
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and new qdisc with the same name. To join a slave to the equalizer
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you should just set this qdisc on a device f.e.
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# tc qdisc add dev eth0 root teql0
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# tc qdisc add dev eth1 root teql0
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That's all. Full PnP 8)
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Applicability.
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--------------
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1. Slave devices MUST be active devices, i.e., they must raise the tbusy
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signal and generate EOI events. If you want to equalize virtual devices
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like tunnels, use a normal eql device.
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2. This device puts no limitations on physical slave characteristics
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f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
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Certainly, large difference in link speeds will make the resulting
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eqalized link unusable, because of huge packet reordering.
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I estimate an upper useful difference as ~10 times.
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3. If the slave requires address resolution, only protocols using
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neighbour cache (IPv4/IPv6) will work over the equalized link.
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Other protocols are still allowed to use the slave device directly,
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which will not break load balancing, though native slave
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traffic will have the highest priority. */
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struct teql_master
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{
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struct Qdisc_ops qops;
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struct net_device *dev;
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struct Qdisc *slaves;
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struct list_head master_list;
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struct net_device_stats stats;
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};
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struct teql_sched_data
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{
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struct Qdisc *next;
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struct teql_master *m;
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struct neighbour *ncache;
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struct sk_buff_head q;
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};
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#define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
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#define FMASK (IFF_BROADCAST|IFF_POINTOPOINT)
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/* "teql*" qdisc routines */
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static int
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teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct teql_sched_data *q = qdisc_priv(sch);
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if (q->q.qlen < dev->tx_queue_len) {
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__skb_queue_tail(&q->q, skb);
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sch->bstats.bytes += qdisc_pkt_len(skb);
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sch->bstats.packets++;
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return 0;
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}
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kfree_skb(skb);
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sch->qstats.drops++;
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return NET_XMIT_DROP;
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}
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static int
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teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct teql_sched_data *q = qdisc_priv(sch);
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__skb_queue_head(&q->q, skb);
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sch->qstats.requeues++;
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return 0;
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}
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static struct sk_buff *
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teql_dequeue(struct Qdisc* sch)
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{
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struct teql_sched_data *dat = qdisc_priv(sch);
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struct netdev_queue *dat_queue;
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struct sk_buff *skb;
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skb = __skb_dequeue(&dat->q);
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dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
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if (skb == NULL) {
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struct net_device *m = qdisc_dev(dat_queue->qdisc);
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if (m) {
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dat->m->slaves = sch;
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netif_wake_queue(m);
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}
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}
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sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
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return skb;
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}
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static __inline__ void
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teql_neigh_release(struct neighbour *n)
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{
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if (n)
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neigh_release(n);
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}
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static void
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teql_reset(struct Qdisc* sch)
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{
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struct teql_sched_data *dat = qdisc_priv(sch);
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skb_queue_purge(&dat->q);
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sch->q.qlen = 0;
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teql_neigh_release(xchg(&dat->ncache, NULL));
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}
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static void
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teql_destroy(struct Qdisc* sch)
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{
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struct Qdisc *q, *prev;
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struct teql_sched_data *dat = qdisc_priv(sch);
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struct teql_master *master = dat->m;
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if ((prev = master->slaves) != NULL) {
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do {
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q = NEXT_SLAVE(prev);
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if (q == sch) {
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NEXT_SLAVE(prev) = NEXT_SLAVE(q);
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if (q == master->slaves) {
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master->slaves = NEXT_SLAVE(q);
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if (q == master->slaves) {
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struct netdev_queue *txq;
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spinlock_t *root_lock;
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txq = netdev_get_tx_queue(master->dev, 0);
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master->slaves = NULL;
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root_lock = qdisc_root_sleeping_lock(txq->qdisc);
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spin_lock_bh(root_lock);
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qdisc_reset(txq->qdisc);
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spin_unlock_bh(root_lock);
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}
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}
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skb_queue_purge(&dat->q);
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teql_neigh_release(xchg(&dat->ncache, NULL));
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break;
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}
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} while ((prev = q) != master->slaves);
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}
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}
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static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct teql_master *m = (struct teql_master*)sch->ops;
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struct teql_sched_data *q = qdisc_priv(sch);
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if (dev->hard_header_len > m->dev->hard_header_len)
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return -EINVAL;
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if (m->dev == dev)
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return -ELOOP;
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q->m = m;
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skb_queue_head_init(&q->q);
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if (m->slaves) {
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if (m->dev->flags & IFF_UP) {
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if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
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|| (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
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|| (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
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|| dev->mtu < m->dev->mtu)
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return -EINVAL;
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} else {
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if (!(dev->flags&IFF_POINTOPOINT))
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m->dev->flags &= ~IFF_POINTOPOINT;
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if (!(dev->flags&IFF_BROADCAST))
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m->dev->flags &= ~IFF_BROADCAST;
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if (!(dev->flags&IFF_MULTICAST))
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m->dev->flags &= ~IFF_MULTICAST;
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if (dev->mtu < m->dev->mtu)
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m->dev->mtu = dev->mtu;
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}
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q->next = NEXT_SLAVE(m->slaves);
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NEXT_SLAVE(m->slaves) = sch;
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} else {
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q->next = sch;
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m->slaves = sch;
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m->dev->mtu = dev->mtu;
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m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
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}
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return 0;
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}
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static int
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__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
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{
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struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
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struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
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struct neighbour *mn = skb->dst->neighbour;
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struct neighbour *n = q->ncache;
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if (mn->tbl == NULL)
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return -EINVAL;
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if (n && n->tbl == mn->tbl &&
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memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
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atomic_inc(&n->refcnt);
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} else {
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n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
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if (IS_ERR(n))
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return PTR_ERR(n);
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}
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if (neigh_event_send(n, skb_res) == 0) {
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int err;
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read_lock(&n->lock);
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err = dev_hard_header(skb, dev, ntohs(skb->protocol),
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n->ha, NULL, skb->len);
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read_unlock(&n->lock);
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if (err < 0) {
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neigh_release(n);
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return -EINVAL;
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}
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teql_neigh_release(xchg(&q->ncache, n));
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return 0;
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}
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neigh_release(n);
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return (skb_res == NULL) ? -EAGAIN : 1;
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}
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static inline int teql_resolve(struct sk_buff *skb,
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struct sk_buff *skb_res, struct net_device *dev)
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{
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struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
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if (txq->qdisc == &noop_qdisc)
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return -ENODEV;
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if (dev->header_ops == NULL ||
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skb->dst == NULL ||
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skb->dst->neighbour == NULL)
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return 0;
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return __teql_resolve(skb, skb_res, dev);
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}
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static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct teql_master *master = netdev_priv(dev);
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struct Qdisc *start, *q;
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int busy;
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int nores;
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int subq = skb_get_queue_mapping(skb);
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struct sk_buff *skb_res = NULL;
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start = master->slaves;
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restart:
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nores = 0;
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busy = 0;
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if ((q = start) == NULL)
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goto drop;
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do {
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struct net_device *slave = qdisc_dev(q);
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struct netdev_queue *slave_txq;
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slave_txq = netdev_get_tx_queue(slave, 0);
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if (slave_txq->qdisc_sleeping != q)
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continue;
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if (__netif_subqueue_stopped(slave, subq) ||
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!netif_running(slave)) {
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busy = 1;
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continue;
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}
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switch (teql_resolve(skb, skb_res, slave)) {
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case 0:
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if (__netif_tx_trylock(slave_txq)) {
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if (!netif_tx_queue_stopped(slave_txq) &&
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!netif_tx_queue_frozen(slave_txq) &&
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slave->hard_start_xmit(skb, slave) == 0) {
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__netif_tx_unlock(slave_txq);
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master->slaves = NEXT_SLAVE(q);
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netif_wake_queue(dev);
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master->stats.tx_packets++;
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master->stats.tx_bytes +=
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qdisc_pkt_len(skb);
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return 0;
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}
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__netif_tx_unlock(slave_txq);
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}
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if (netif_queue_stopped(dev))
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busy = 1;
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break;
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case 1:
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master->slaves = NEXT_SLAVE(q);
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return 0;
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default:
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nores = 1;
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break;
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}
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__skb_pull(skb, skb_network_offset(skb));
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} while ((q = NEXT_SLAVE(q)) != start);
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if (nores && skb_res == NULL) {
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skb_res = skb;
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goto restart;
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}
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if (busy) {
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netif_stop_queue(dev);
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return 1;
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}
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master->stats.tx_errors++;
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drop:
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master->stats.tx_dropped++;
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dev_kfree_skb(skb);
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return 0;
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}
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static int teql_master_open(struct net_device *dev)
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{
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struct Qdisc * q;
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struct teql_master *m = netdev_priv(dev);
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int mtu = 0xFFFE;
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unsigned flags = IFF_NOARP|IFF_MULTICAST;
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if (m->slaves == NULL)
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return -EUNATCH;
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flags = FMASK;
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q = m->slaves;
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do {
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struct net_device *slave = qdisc_dev(q);
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if (slave == NULL)
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return -EUNATCH;
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if (slave->mtu < mtu)
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mtu = slave->mtu;
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if (slave->hard_header_len > LL_MAX_HEADER)
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return -EINVAL;
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/* If all the slaves are BROADCAST, master is BROADCAST
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If all the slaves are PtP, master is PtP
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Otherwise, master is NBMA.
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*/
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if (!(slave->flags&IFF_POINTOPOINT))
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flags &= ~IFF_POINTOPOINT;
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if (!(slave->flags&IFF_BROADCAST))
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flags &= ~IFF_BROADCAST;
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if (!(slave->flags&IFF_MULTICAST))
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flags &= ~IFF_MULTICAST;
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} while ((q = NEXT_SLAVE(q)) != m->slaves);
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m->dev->mtu = mtu;
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m->dev->flags = (m->dev->flags&~FMASK) | flags;
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netif_start_queue(m->dev);
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return 0;
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}
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static int teql_master_close(struct net_device *dev)
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{
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netif_stop_queue(dev);
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return 0;
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}
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static struct net_device_stats *teql_master_stats(struct net_device *dev)
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{
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struct teql_master *m = netdev_priv(dev);
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return &m->stats;
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}
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static int teql_master_mtu(struct net_device *dev, int new_mtu)
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{
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struct teql_master *m = netdev_priv(dev);
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struct Qdisc *q;
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if (new_mtu < 68)
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return -EINVAL;
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q = m->slaves;
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if (q) {
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do {
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if (new_mtu > qdisc_dev(q)->mtu)
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return -EINVAL;
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} while ((q=NEXT_SLAVE(q)) != m->slaves);
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}
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dev->mtu = new_mtu;
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return 0;
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}
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static __init void teql_master_setup(struct net_device *dev)
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{
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struct teql_master *master = netdev_priv(dev);
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struct Qdisc_ops *ops = &master->qops;
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master->dev = dev;
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ops->priv_size = sizeof(struct teql_sched_data);
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ops->enqueue = teql_enqueue;
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ops->dequeue = teql_dequeue;
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ops->requeue = teql_requeue;
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ops->init = teql_qdisc_init;
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ops->reset = teql_reset;
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ops->destroy = teql_destroy;
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ops->owner = THIS_MODULE;
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dev->open = teql_master_open;
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dev->hard_start_xmit = teql_master_xmit;
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dev->stop = teql_master_close;
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dev->get_stats = teql_master_stats;
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dev->change_mtu = teql_master_mtu;
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dev->type = ARPHRD_VOID;
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dev->mtu = 1500;
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dev->tx_queue_len = 100;
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dev->flags = IFF_NOARP;
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dev->hard_header_len = LL_MAX_HEADER;
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}
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static LIST_HEAD(master_dev_list);
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static int max_equalizers = 1;
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module_param(max_equalizers, int, 0);
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MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
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static int __init teql_init(void)
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{
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int i;
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int err = -ENODEV;
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for (i = 0; i < max_equalizers; i++) {
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struct net_device *dev;
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struct teql_master *master;
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dev = alloc_netdev(sizeof(struct teql_master),
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"teql%d", teql_master_setup);
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if (!dev) {
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err = -ENOMEM;
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break;
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}
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if ((err = register_netdev(dev))) {
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free_netdev(dev);
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break;
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}
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master = netdev_priv(dev);
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strlcpy(master->qops.id, dev->name, IFNAMSIZ);
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err = register_qdisc(&master->qops);
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if (err) {
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unregister_netdev(dev);
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free_netdev(dev);
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break;
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}
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list_add_tail(&master->master_list, &master_dev_list);
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}
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return i ? 0 : err;
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}
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static void __exit teql_exit(void)
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{
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struct teql_master *master, *nxt;
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list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
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list_del(&master->master_list);
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unregister_qdisc(&master->qops);
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unregister_netdev(master->dev);
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free_netdev(master->dev);
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}
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}
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module_init(teql_init);
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module_exit(teql_exit);
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MODULE_LICENSE("GPL");
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