![Thomas Graf](/assets/img/avatar_default.png)
Adds qdisc_alloc() to share code between qdisc_create() and qdisc_create_dflt(). Hides the qdisc alignment behind macros and makes use of them. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
612 lines
15 KiB
C
612 lines
15 KiB
C
/*
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* net/sched/sch_generic.c Generic packet scheduler routines.
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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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* Jamal Hadi Salim, <hadi@cyberus.ca> 990601
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* - Ingress support
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*/
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/bitops.h>
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#include <linux/config.h>
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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/sched.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/init.h>
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#include <linux/rcupdate.h>
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#include <linux/list.h>
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#include <net/sock.h>
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#include <net/pkt_sched.h>
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/* Main transmission queue. */
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/* Main qdisc structure lock.
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However, modifications
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to data, participating in scheduling must be additionally
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protected with dev->queue_lock spinlock.
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The idea is the following:
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- enqueue, dequeue are serialized via top level device
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spinlock dev->queue_lock.
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- tree walking is protected by read_lock_bh(qdisc_tree_lock)
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and this lock is used only in process context.
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- updates to tree are made under rtnl semaphore or
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from softirq context (__qdisc_destroy rcu-callback)
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hence this lock needs local bh disabling.
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qdisc_tree_lock must be grabbed BEFORE dev->queue_lock!
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*/
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DEFINE_RWLOCK(qdisc_tree_lock);
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void qdisc_lock_tree(struct net_device *dev)
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{
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write_lock_bh(&qdisc_tree_lock);
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spin_lock_bh(&dev->queue_lock);
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}
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void qdisc_unlock_tree(struct net_device *dev)
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{
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spin_unlock_bh(&dev->queue_lock);
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write_unlock_bh(&qdisc_tree_lock);
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}
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/*
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dev->queue_lock serializes queue accesses for this device
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AND dev->qdisc pointer itself.
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dev->xmit_lock serializes accesses to device driver.
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dev->queue_lock and dev->xmit_lock are mutually exclusive,
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if one is grabbed, another must be free.
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*/
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/* Kick device.
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Note, that this procedure can be called by a watchdog timer, so that
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we do not check dev->tbusy flag here.
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Returns: 0 - queue is empty.
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>0 - queue is not empty, but throttled.
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<0 - queue is not empty. Device is throttled, if dev->tbusy != 0.
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NOTE: Called under dev->queue_lock with locally disabled BH.
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*/
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int qdisc_restart(struct net_device *dev)
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{
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struct Qdisc *q = dev->qdisc;
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struct sk_buff *skb;
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/* Dequeue packet */
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if ((skb = q->dequeue(q)) != NULL) {
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unsigned nolock = (dev->features & NETIF_F_LLTX);
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/*
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* When the driver has LLTX set it does its own locking
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* in start_xmit. No need to add additional overhead by
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* locking again. These checks are worth it because
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* even uncongested locks can be quite expensive.
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* The driver can do trylock like here too, in case
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* of lock congestion it should return -1 and the packet
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* will be requeued.
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*/
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if (!nolock) {
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if (!spin_trylock(&dev->xmit_lock)) {
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collision:
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/* So, someone grabbed the driver. */
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/* It may be transient configuration error,
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when hard_start_xmit() recurses. We detect
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it by checking xmit owner and drop the
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packet when deadloop is detected.
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*/
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if (dev->xmit_lock_owner == smp_processor_id()) {
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kfree_skb(skb);
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if (net_ratelimit())
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printk(KERN_DEBUG "Dead loop on netdevice %s, fix it urgently!\n", dev->name);
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return -1;
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}
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__get_cpu_var(netdev_rx_stat).cpu_collision++;
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goto requeue;
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}
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/* Remember that the driver is grabbed by us. */
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dev->xmit_lock_owner = smp_processor_id();
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}
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{
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/* And release queue */
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spin_unlock(&dev->queue_lock);
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if (!netif_queue_stopped(dev)) {
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int ret;
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if (netdev_nit)
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dev_queue_xmit_nit(skb, dev);
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ret = dev->hard_start_xmit(skb, dev);
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if (ret == NETDEV_TX_OK) {
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if (!nolock) {
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dev->xmit_lock_owner = -1;
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spin_unlock(&dev->xmit_lock);
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}
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spin_lock(&dev->queue_lock);
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return -1;
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}
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if (ret == NETDEV_TX_LOCKED && nolock) {
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spin_lock(&dev->queue_lock);
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goto collision;
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}
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}
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/* NETDEV_TX_BUSY - we need to requeue */
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/* Release the driver */
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if (!nolock) {
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dev->xmit_lock_owner = -1;
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spin_unlock(&dev->xmit_lock);
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}
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spin_lock(&dev->queue_lock);
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q = dev->qdisc;
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}
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/* Device kicked us out :(
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This is possible in three cases:
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0. driver is locked
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1. fastroute is enabled
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2. device cannot determine busy state
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before start of transmission (f.e. dialout)
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3. device is buggy (ppp)
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*/
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requeue:
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q->ops->requeue(skb, q);
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netif_schedule(dev);
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return 1;
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}
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BUG_ON((int) q->q.qlen < 0);
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return q->q.qlen;
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}
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static void dev_watchdog(unsigned long arg)
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{
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struct net_device *dev = (struct net_device *)arg;
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spin_lock(&dev->xmit_lock);
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if (dev->qdisc != &noop_qdisc) {
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if (netif_device_present(dev) &&
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netif_running(dev) &&
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netif_carrier_ok(dev)) {
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if (netif_queue_stopped(dev) &&
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(jiffies - dev->trans_start) > dev->watchdog_timeo) {
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printk(KERN_INFO "NETDEV WATCHDOG: %s: transmit timed out\n", dev->name);
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dev->tx_timeout(dev);
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}
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if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
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dev_hold(dev);
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}
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}
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spin_unlock(&dev->xmit_lock);
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dev_put(dev);
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}
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static void dev_watchdog_init(struct net_device *dev)
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{
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init_timer(&dev->watchdog_timer);
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dev->watchdog_timer.data = (unsigned long)dev;
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dev->watchdog_timer.function = dev_watchdog;
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}
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void __netdev_watchdog_up(struct net_device *dev)
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{
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if (dev->tx_timeout) {
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if (dev->watchdog_timeo <= 0)
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dev->watchdog_timeo = 5*HZ;
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if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
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dev_hold(dev);
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}
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}
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static void dev_watchdog_up(struct net_device *dev)
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{
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spin_lock_bh(&dev->xmit_lock);
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__netdev_watchdog_up(dev);
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spin_unlock_bh(&dev->xmit_lock);
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}
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static void dev_watchdog_down(struct net_device *dev)
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{
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spin_lock_bh(&dev->xmit_lock);
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if (del_timer(&dev->watchdog_timer))
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__dev_put(dev);
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spin_unlock_bh(&dev->xmit_lock);
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}
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/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
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under all circumstances. It is difficult to invent anything faster or
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cheaper.
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*/
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static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
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{
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kfree_skb(skb);
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return NET_XMIT_CN;
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}
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static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
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{
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return NULL;
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}
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static int noop_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
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{
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if (net_ratelimit())
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printk(KERN_DEBUG "%s deferred output. It is buggy.\n",
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skb->dev->name);
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kfree_skb(skb);
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return NET_XMIT_CN;
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}
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struct Qdisc_ops noop_qdisc_ops = {
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.id = "noop",
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.priv_size = 0,
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.enqueue = noop_enqueue,
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.dequeue = noop_dequeue,
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.requeue = noop_requeue,
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.owner = THIS_MODULE,
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};
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struct Qdisc noop_qdisc = {
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.enqueue = noop_enqueue,
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.dequeue = noop_dequeue,
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.flags = TCQ_F_BUILTIN,
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.ops = &noop_qdisc_ops,
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.list = LIST_HEAD_INIT(noop_qdisc.list),
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};
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static struct Qdisc_ops noqueue_qdisc_ops = {
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.id = "noqueue",
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.priv_size = 0,
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.enqueue = noop_enqueue,
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.dequeue = noop_dequeue,
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.requeue = noop_requeue,
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.owner = THIS_MODULE,
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};
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static struct Qdisc noqueue_qdisc = {
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.enqueue = NULL,
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.dequeue = noop_dequeue,
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.flags = TCQ_F_BUILTIN,
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.ops = &noqueue_qdisc_ops,
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.list = LIST_HEAD_INIT(noqueue_qdisc.list),
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};
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static const u8 prio2band[TC_PRIO_MAX+1] =
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{ 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 };
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/* 3-band FIFO queue: old style, but should be a bit faster than
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generic prio+fifo combination.
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*/
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#define PFIFO_FAST_BANDS 3
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static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
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struct Qdisc *qdisc)
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{
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struct sk_buff_head *list = qdisc_priv(qdisc);
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return list + prio2band[skb->priority & TC_PRIO_MAX];
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}
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static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
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{
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struct sk_buff_head *list = prio2list(skb, qdisc);
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if (skb_queue_len(list) < qdisc->dev->tx_queue_len) {
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qdisc->q.qlen++;
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return __qdisc_enqueue_tail(skb, qdisc, list);
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}
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return qdisc_drop(skb, qdisc);
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}
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static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
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{
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int prio;
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struct sk_buff_head *list = qdisc_priv(qdisc);
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for (prio = 0; prio < PFIFO_FAST_BANDS; prio++, list++) {
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struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
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if (skb) {
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qdisc->q.qlen--;
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return skb;
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}
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}
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return NULL;
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}
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static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
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{
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qdisc->q.qlen++;
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return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
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}
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static void pfifo_fast_reset(struct Qdisc* qdisc)
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{
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int prio;
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struct sk_buff_head *list = qdisc_priv(qdisc);
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for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
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__qdisc_reset_queue(qdisc, list + prio);
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qdisc->qstats.backlog = 0;
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qdisc->q.qlen = 0;
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}
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static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
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{
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struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
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memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
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RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
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return skb->len;
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rtattr_failure:
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return -1;
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}
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static int pfifo_fast_init(struct Qdisc *qdisc, struct rtattr *opt)
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{
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int prio;
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struct sk_buff_head *list = qdisc_priv(qdisc);
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for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
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skb_queue_head_init(list + prio);
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return 0;
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}
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static struct Qdisc_ops pfifo_fast_ops = {
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.id = "pfifo_fast",
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.priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
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.enqueue = pfifo_fast_enqueue,
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.dequeue = pfifo_fast_dequeue,
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.requeue = pfifo_fast_requeue,
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.init = pfifo_fast_init,
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.reset = pfifo_fast_reset,
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.dump = pfifo_fast_dump,
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.owner = THIS_MODULE,
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};
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struct Qdisc *qdisc_alloc(struct net_device *dev, struct Qdisc_ops *ops)
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{
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void *p;
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struct Qdisc *sch;
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unsigned int size;
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int err = -ENOBUFS;
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/* ensure that the Qdisc and the private data are 32-byte aligned */
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size = QDISC_ALIGN(sizeof(*sch));
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size += ops->priv_size + (QDISC_ALIGNTO - 1);
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p = kmalloc(size, GFP_KERNEL);
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if (!p)
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goto errout;
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memset(p, 0, size);
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sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
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sch->padded = (char *) sch - (char *) p;
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INIT_LIST_HEAD(&sch->list);
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skb_queue_head_init(&sch->q);
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sch->ops = ops;
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sch->enqueue = ops->enqueue;
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sch->dequeue = ops->dequeue;
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sch->dev = dev;
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dev_hold(dev);
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sch->stats_lock = &dev->queue_lock;
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atomic_set(&sch->refcnt, 1);
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return sch;
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errout:
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return ERR_PTR(-err);
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}
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struct Qdisc * qdisc_create_dflt(struct net_device *dev, struct Qdisc_ops *ops)
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{
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struct Qdisc *sch;
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sch = qdisc_alloc(dev, ops);
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if (IS_ERR(sch))
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goto errout;
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if (!ops->init || ops->init(sch, NULL) == 0)
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return sch;
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errout:
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return NULL;
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}
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/* Under dev->queue_lock and BH! */
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void qdisc_reset(struct Qdisc *qdisc)
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{
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struct Qdisc_ops *ops = qdisc->ops;
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if (ops->reset)
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ops->reset(qdisc);
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}
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/* this is the rcu callback function to clean up a qdisc when there
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* are no further references to it */
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static void __qdisc_destroy(struct rcu_head *head)
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{
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struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
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struct Qdisc_ops *ops = qdisc->ops;
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#ifdef CONFIG_NET_ESTIMATOR
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gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
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#endif
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write_lock(&qdisc_tree_lock);
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if (ops->reset)
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ops->reset(qdisc);
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if (ops->destroy)
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ops->destroy(qdisc);
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write_unlock(&qdisc_tree_lock);
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module_put(ops->owner);
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dev_put(qdisc->dev);
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kfree((char *) qdisc - qdisc->padded);
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}
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/* Under dev->queue_lock and BH! */
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void qdisc_destroy(struct Qdisc *qdisc)
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{
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struct list_head cql = LIST_HEAD_INIT(cql);
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struct Qdisc *cq, *q, *n;
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if (qdisc->flags & TCQ_F_BUILTIN ||
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!atomic_dec_and_test(&qdisc->refcnt))
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return;
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if (!list_empty(&qdisc->list)) {
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if (qdisc->ops->cl_ops == NULL)
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list_del(&qdisc->list);
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else
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list_move(&qdisc->list, &cql);
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}
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/* unlink inner qdiscs from dev->qdisc_list immediately */
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list_for_each_entry(cq, &cql, list)
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list_for_each_entry_safe(q, n, &qdisc->dev->qdisc_list, list)
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if (TC_H_MAJ(q->parent) == TC_H_MAJ(cq->handle)) {
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if (q->ops->cl_ops == NULL)
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list_del_init(&q->list);
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else
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list_move_tail(&q->list, &cql);
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}
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list_for_each_entry_safe(cq, n, &cql, list)
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list_del_init(&cq->list);
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call_rcu(&qdisc->q_rcu, __qdisc_destroy);
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}
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void dev_activate(struct net_device *dev)
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{
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/* No queueing discipline is attached to device;
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create default one i.e. pfifo_fast for devices,
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which need queueing and noqueue_qdisc for
|
|
virtual interfaces
|
|
*/
|
|
|
|
if (dev->qdisc_sleeping == &noop_qdisc) {
|
|
struct Qdisc *qdisc;
|
|
if (dev->tx_queue_len) {
|
|
qdisc = qdisc_create_dflt(dev, &pfifo_fast_ops);
|
|
if (qdisc == NULL) {
|
|
printk(KERN_INFO "%s: activation failed\n", dev->name);
|
|
return;
|
|
}
|
|
write_lock_bh(&qdisc_tree_lock);
|
|
list_add_tail(&qdisc->list, &dev->qdisc_list);
|
|
write_unlock_bh(&qdisc_tree_lock);
|
|
} else {
|
|
qdisc = &noqueue_qdisc;
|
|
}
|
|
write_lock_bh(&qdisc_tree_lock);
|
|
dev->qdisc_sleeping = qdisc;
|
|
write_unlock_bh(&qdisc_tree_lock);
|
|
}
|
|
|
|
if (!netif_carrier_ok(dev))
|
|
/* Delay activation until next carrier-on event */
|
|
return;
|
|
|
|
spin_lock_bh(&dev->queue_lock);
|
|
rcu_assign_pointer(dev->qdisc, dev->qdisc_sleeping);
|
|
if (dev->qdisc != &noqueue_qdisc) {
|
|
dev->trans_start = jiffies;
|
|
dev_watchdog_up(dev);
|
|
}
|
|
spin_unlock_bh(&dev->queue_lock);
|
|
}
|
|
|
|
void dev_deactivate(struct net_device *dev)
|
|
{
|
|
struct Qdisc *qdisc;
|
|
|
|
spin_lock_bh(&dev->queue_lock);
|
|
qdisc = dev->qdisc;
|
|
dev->qdisc = &noop_qdisc;
|
|
|
|
qdisc_reset(qdisc);
|
|
|
|
spin_unlock_bh(&dev->queue_lock);
|
|
|
|
dev_watchdog_down(dev);
|
|
|
|
while (test_bit(__LINK_STATE_SCHED, &dev->state))
|
|
yield();
|
|
|
|
spin_unlock_wait(&dev->xmit_lock);
|
|
}
|
|
|
|
void dev_init_scheduler(struct net_device *dev)
|
|
{
|
|
qdisc_lock_tree(dev);
|
|
dev->qdisc = &noop_qdisc;
|
|
dev->qdisc_sleeping = &noop_qdisc;
|
|
INIT_LIST_HEAD(&dev->qdisc_list);
|
|
qdisc_unlock_tree(dev);
|
|
|
|
dev_watchdog_init(dev);
|
|
}
|
|
|
|
void dev_shutdown(struct net_device *dev)
|
|
{
|
|
struct Qdisc *qdisc;
|
|
|
|
qdisc_lock_tree(dev);
|
|
qdisc = dev->qdisc_sleeping;
|
|
dev->qdisc = &noop_qdisc;
|
|
dev->qdisc_sleeping = &noop_qdisc;
|
|
qdisc_destroy(qdisc);
|
|
#if defined(CONFIG_NET_SCH_INGRESS) || defined(CONFIG_NET_SCH_INGRESS_MODULE)
|
|
if ((qdisc = dev->qdisc_ingress) != NULL) {
|
|
dev->qdisc_ingress = NULL;
|
|
qdisc_destroy(qdisc);
|
|
}
|
|
#endif
|
|
BUG_TRAP(!timer_pending(&dev->watchdog_timer));
|
|
qdisc_unlock_tree(dev);
|
|
}
|
|
|
|
EXPORT_SYMBOL(__netdev_watchdog_up);
|
|
EXPORT_SYMBOL(noop_qdisc);
|
|
EXPORT_SYMBOL(noop_qdisc_ops);
|
|
EXPORT_SYMBOL(qdisc_create_dflt);
|
|
EXPORT_SYMBOL(qdisc_alloc);
|
|
EXPORT_SYMBOL(qdisc_destroy);
|
|
EXPORT_SYMBOL(qdisc_reset);
|
|
EXPORT_SYMBOL(qdisc_restart);
|
|
EXPORT_SYMBOL(qdisc_lock_tree);
|
|
EXPORT_SYMBOL(qdisc_unlock_tree);
|