diff options
Diffstat (limited to 'kernel/net/sched/sch_generic.c')
| -rw-r--r-- | kernel/net/sched/sch_generic.c | 990 |
1 files changed, 990 insertions, 0 deletions
diff --git a/kernel/net/sched/sch_generic.c b/kernel/net/sched/sch_generic.c new file mode 100644 index 000000000..1e346523f --- /dev/null +++ b/kernel/net/sched/sch_generic.c @@ -0,0 +1,990 @@ +/* + * net/sched/sch_generic.c Generic packet scheduler routines. + * + * 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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + * Jamal Hadi Salim, <hadi@cyberus.ca> 990601 + * - Ingress support + */ + +#include <linux/bitops.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/rtnetlink.h> +#include <linux/init.h> +#include <linux/rcupdate.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/if_vlan.h> +#include <net/sch_generic.h> +#include <net/pkt_sched.h> +#include <net/dst.h> + +/* Qdisc to use by default */ +const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; +EXPORT_SYMBOL(default_qdisc_ops); + +/* Main transmission queue. */ + +/* Modifications to data participating in scheduling must be protected with + * qdisc_lock(qdisc) spinlock. + * + * The idea is the following: + * - enqueue, dequeue are serialized via qdisc root lock + * - ingress filtering is also serialized via qdisc root lock + * - updates to tree and tree walking are only done under the rtnl mutex. + */ + +static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) +{ + q->gso_skb = skb; + q->qstats.requeues++; + q->q.qlen++; /* it's still part of the queue */ + __netif_schedule(q); + + return 0; +} + +static void try_bulk_dequeue_skb(struct Qdisc *q, + struct sk_buff *skb, + const struct netdev_queue *txq, + int *packets) +{ + int bytelimit = qdisc_avail_bulklimit(txq) - skb->len; + + while (bytelimit > 0) { + struct sk_buff *nskb = q->dequeue(q); + + if (!nskb) + break; + + bytelimit -= nskb->len; /* covers GSO len */ + skb->next = nskb; + skb = nskb; + (*packets)++; /* GSO counts as one pkt */ + } + skb->next = NULL; +} + +/* Note that dequeue_skb can possibly return a SKB list (via skb->next). + * A requeued skb (via q->gso_skb) can also be a SKB list. + */ +static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate, + int *packets) +{ + struct sk_buff *skb = q->gso_skb; + const struct netdev_queue *txq = q->dev_queue; + + *packets = 1; + *validate = true; + if (unlikely(skb)) { + /* check the reason of requeuing without tx lock first */ + txq = skb_get_tx_queue(txq->dev, skb); + if (!netif_xmit_frozen_or_stopped(txq)) { + q->gso_skb = NULL; + q->q.qlen--; + } else + skb = NULL; + /* skb in gso_skb were already validated */ + *validate = false; + } else { + if (!(q->flags & TCQ_F_ONETXQUEUE) || + !netif_xmit_frozen_or_stopped(txq)) { + skb = q->dequeue(q); + if (skb && qdisc_may_bulk(q)) + try_bulk_dequeue_skb(q, skb, txq, packets); + } + } + return skb; +} + +static inline int handle_dev_cpu_collision(struct sk_buff *skb, + struct netdev_queue *dev_queue, + struct Qdisc *q) +{ + int ret; + + if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) { + /* + * Same CPU holding the lock. It may be a transient + * configuration error, when hard_start_xmit() recurses. We + * detect it by checking xmit owner and drop the packet when + * deadloop is detected. Return OK to try the next skb. + */ + kfree_skb_list(skb); + net_warn_ratelimited("Dead loop on netdevice %s, fix it urgently!\n", + dev_queue->dev->name); + ret = qdisc_qlen(q); + } else { + /* + * Another cpu is holding lock, requeue & delay xmits for + * some time. + */ + __this_cpu_inc(softnet_data.cpu_collision); + ret = dev_requeue_skb(skb, q); + } + + return ret; +} + +/* + * Transmit possibly several skbs, and handle the return status as + * required. Holding the __QDISC___STATE_RUNNING bit guarantees that + * only one CPU can execute this function. + * + * Returns to the caller: + * 0 - queue is empty or throttled. + * >0 - queue is not empty. + */ +int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, + struct net_device *dev, struct netdev_queue *txq, + spinlock_t *root_lock, bool validate) +{ + int ret = NETDEV_TX_BUSY; + + /* And release qdisc */ + spin_unlock(root_lock); + + /* Note that we validate skb (GSO, checksum, ...) outside of locks */ + if (validate) + skb = validate_xmit_skb_list(skb, dev); + + if (skb) { + HARD_TX_LOCK(dev, txq, smp_processor_id()); + if (!netif_xmit_frozen_or_stopped(txq)) + skb = dev_hard_start_xmit(skb, dev, txq, &ret); + + HARD_TX_UNLOCK(dev, txq); + } + spin_lock(root_lock); + + if (dev_xmit_complete(ret)) { + /* Driver sent out skb successfully or skb was consumed */ + ret = qdisc_qlen(q); + } else if (ret == NETDEV_TX_LOCKED) { + /* Driver try lock failed */ + ret = handle_dev_cpu_collision(skb, txq, q); + } else { + /* Driver returned NETDEV_TX_BUSY - requeue skb */ + if (unlikely(ret != NETDEV_TX_BUSY)) + net_warn_ratelimited("BUG %s code %d qlen %d\n", + dev->name, ret, q->q.qlen); + + ret = dev_requeue_skb(skb, q); + } + + if (ret && netif_xmit_frozen_or_stopped(txq)) + ret = 0; + + return ret; +} + +/* + * NOTE: Called under qdisc_lock(q) with locally disabled BH. + * + * __QDISC___STATE_RUNNING guarantees only one CPU can process + * this qdisc at a time. qdisc_lock(q) serializes queue accesses for + * this queue. + * + * netif_tx_lock serializes accesses to device driver. + * + * qdisc_lock(q) and netif_tx_lock are mutually exclusive, + * if one is grabbed, another must be free. + * + * Note, that this procedure can be called by a watchdog timer + * + * Returns to the caller: + * 0 - queue is empty or throttled. + * >0 - queue is not empty. + * + */ +static inline int qdisc_restart(struct Qdisc *q, int *packets) +{ + struct netdev_queue *txq; + struct net_device *dev; + spinlock_t *root_lock; + struct sk_buff *skb; + bool validate; + + /* Dequeue packet */ + skb = dequeue_skb(q, &validate, packets); + if (unlikely(!skb)) + return 0; + + root_lock = qdisc_lock(q); + dev = qdisc_dev(q); + txq = skb_get_tx_queue(dev, skb); + + return sch_direct_xmit(skb, q, dev, txq, root_lock, validate); +} + +void __qdisc_run(struct Qdisc *q) +{ + int quota = weight_p; + int packets; + + while (qdisc_restart(q, &packets)) { + /* + * Ordered by possible occurrence: Postpone processing if + * 1. we've exceeded packet quota + * 2. another process needs the CPU; + */ + quota -= packets; + if (quota <= 0 || need_resched()) { + __netif_schedule(q); + break; + } + } + + qdisc_run_end(q); +} + +unsigned long dev_trans_start(struct net_device *dev) +{ + unsigned long val, res; + unsigned int i; + + if (is_vlan_dev(dev)) + dev = vlan_dev_real_dev(dev); + res = dev->trans_start; + for (i = 0; i < dev->num_tx_queues; i++) { + val = netdev_get_tx_queue(dev, i)->trans_start; + if (val && time_after(val, res)) + res = val; + } + dev->trans_start = res; + + return res; +} +EXPORT_SYMBOL(dev_trans_start); + +static void dev_watchdog(unsigned long arg) +{ + struct net_device *dev = (struct net_device *)arg; + + netif_tx_lock(dev); + if (!qdisc_tx_is_noop(dev)) { + if (netif_device_present(dev) && + netif_running(dev) && + netif_carrier_ok(dev)) { + int some_queue_timedout = 0; + unsigned int i; + unsigned long trans_start; + + for (i = 0; i < dev->num_tx_queues; i++) { + struct netdev_queue *txq; + + txq = netdev_get_tx_queue(dev, i); + /* + * old device drivers set dev->trans_start + */ + trans_start = txq->trans_start ? : dev->trans_start; + if (netif_xmit_stopped(txq) && + time_after(jiffies, (trans_start + + dev->watchdog_timeo))) { + some_queue_timedout = 1; + txq->trans_timeout++; + break; + } + } + + if (some_queue_timedout) { + WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n", + dev->name, netdev_drivername(dev), i); + dev->netdev_ops->ndo_tx_timeout(dev); + } + if (!mod_timer(&dev->watchdog_timer, + round_jiffies(jiffies + + dev->watchdog_timeo))) + dev_hold(dev); + } + } + netif_tx_unlock(dev); + + dev_put(dev); +} + +void __netdev_watchdog_up(struct net_device *dev) +{ + if (dev->netdev_ops->ndo_tx_timeout) { + if (dev->watchdog_timeo <= 0) + dev->watchdog_timeo = 5*HZ; + if (!mod_timer(&dev->watchdog_timer, + round_jiffies(jiffies + dev->watchdog_timeo))) + dev_hold(dev); + } +} + +static void dev_watchdog_up(struct net_device *dev) +{ + __netdev_watchdog_up(dev); +} + +static void dev_watchdog_down(struct net_device *dev) +{ + netif_tx_lock_bh(dev); + if (del_timer(&dev->watchdog_timer)) + dev_put(dev); + netif_tx_unlock_bh(dev); +} + +/** + * netif_carrier_on - set carrier + * @dev: network device + * + * Device has detected that carrier. + */ +void netif_carrier_on(struct net_device *dev) +{ + if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) { + if (dev->reg_state == NETREG_UNINITIALIZED) + return; + atomic_inc(&dev->carrier_changes); + linkwatch_fire_event(dev); + if (netif_running(dev)) + __netdev_watchdog_up(dev); + } +} +EXPORT_SYMBOL(netif_carrier_on); + +/** + * netif_carrier_off - clear carrier + * @dev: network device + * + * Device has detected loss of carrier. + */ +void netif_carrier_off(struct net_device *dev) +{ + if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) { + if (dev->reg_state == NETREG_UNINITIALIZED) + return; + atomic_inc(&dev->carrier_changes); + linkwatch_fire_event(dev); + } +} +EXPORT_SYMBOL(netif_carrier_off); + +/* "NOOP" scheduler: the best scheduler, recommended for all interfaces + under all circumstances. It is difficult to invent anything faster or + cheaper. + */ + +static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc) +{ + kfree_skb(skb); + return NET_XMIT_CN; +} + +static struct sk_buff *noop_dequeue(struct Qdisc *qdisc) +{ + return NULL; +} + +struct Qdisc_ops noop_qdisc_ops __read_mostly = { + .id = "noop", + .priv_size = 0, + .enqueue = noop_enqueue, + .dequeue = noop_dequeue, + .peek = noop_dequeue, + .owner = THIS_MODULE, +}; + +static struct netdev_queue noop_netdev_queue = { + .qdisc = &noop_qdisc, + .qdisc_sleeping = &noop_qdisc, +}; + +struct Qdisc noop_qdisc = { + .enqueue = noop_enqueue, + .dequeue = noop_dequeue, + .flags = TCQ_F_BUILTIN, + .ops = &noop_qdisc_ops, + .list = LIST_HEAD_INIT(noop_qdisc.list), + .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock), + .dev_queue = &noop_netdev_queue, + .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock), +}; +EXPORT_SYMBOL(noop_qdisc); + +static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = { + .id = "noqueue", + .priv_size = 0, + .enqueue = noop_enqueue, + .dequeue = noop_dequeue, + .peek = noop_dequeue, + .owner = THIS_MODULE, +}; + +static struct Qdisc noqueue_qdisc; +static struct netdev_queue noqueue_netdev_queue = { + .qdisc = &noqueue_qdisc, + .qdisc_sleeping = &noqueue_qdisc, +}; + +static struct Qdisc noqueue_qdisc = { + .enqueue = NULL, + .dequeue = noop_dequeue, + .flags = TCQ_F_BUILTIN, + .ops = &noqueue_qdisc_ops, + .list = LIST_HEAD_INIT(noqueue_qdisc.list), + .q.lock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock), + .dev_queue = &noqueue_netdev_queue, + .busylock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.busylock), +}; + + +static const u8 prio2band[TC_PRIO_MAX + 1] = { + 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 +}; + +/* 3-band FIFO queue: old style, but should be a bit faster than + generic prio+fifo combination. + */ + +#define PFIFO_FAST_BANDS 3 + +/* + * Private data for a pfifo_fast scheduler containing: + * - queues for the three band + * - bitmap indicating which of the bands contain skbs + */ +struct pfifo_fast_priv { + u32 bitmap; + struct sk_buff_head q[PFIFO_FAST_BANDS]; +}; + +/* + * Convert a bitmap to the first band number where an skb is queued, where: + * bitmap=0 means there are no skbs on any band. + * bitmap=1 means there is an skb on band 0. + * bitmap=7 means there are skbs on all 3 bands, etc. + */ +static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0}; + +static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv, + int band) +{ + return priv->q + band; +} + +static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc) +{ + if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) { + int band = prio2band[skb->priority & TC_PRIO_MAX]; + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + struct sk_buff_head *list = band2list(priv, band); + + priv->bitmap |= (1 << band); + qdisc->q.qlen++; + return __qdisc_enqueue_tail(skb, qdisc, list); + } + + return qdisc_drop(skb, qdisc); +} + +static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) +{ + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + int band = bitmap2band[priv->bitmap]; + + if (likely(band >= 0)) { + struct sk_buff_head *list = band2list(priv, band); + struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list); + + qdisc->q.qlen--; + if (skb_queue_empty(list)) + priv->bitmap &= ~(1 << band); + + return skb; + } + + return NULL; +} + +static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc) +{ + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + int band = bitmap2band[priv->bitmap]; + + if (band >= 0) { + struct sk_buff_head *list = band2list(priv, band); + + return skb_peek(list); + } + + return NULL; +} + +static void pfifo_fast_reset(struct Qdisc *qdisc) +{ + int prio; + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + + for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) + __qdisc_reset_queue(qdisc, band2list(priv, prio)); + + priv->bitmap = 0; + qdisc->qstats.backlog = 0; + qdisc->q.qlen = 0; +} + +static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb) +{ + struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS }; + + memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1); + if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) + goto nla_put_failure; + return skb->len; + +nla_put_failure: + return -1; +} + +static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt) +{ + int prio; + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + + for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) + __skb_queue_head_init(band2list(priv, prio)); + + /* Can by-pass the queue discipline */ + qdisc->flags |= TCQ_F_CAN_BYPASS; + return 0; +} + +struct Qdisc_ops pfifo_fast_ops __read_mostly = { + .id = "pfifo_fast", + .priv_size = sizeof(struct pfifo_fast_priv), + .enqueue = pfifo_fast_enqueue, + .dequeue = pfifo_fast_dequeue, + .peek = pfifo_fast_peek, + .init = pfifo_fast_init, + .reset = pfifo_fast_reset, + .dump = pfifo_fast_dump, + .owner = THIS_MODULE, +}; + +static struct lock_class_key qdisc_tx_busylock; + +struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, + const struct Qdisc_ops *ops) +{ + void *p; + struct Qdisc *sch; + unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size; + int err = -ENOBUFS; + struct net_device *dev = dev_queue->dev; + + p = kzalloc_node(size, GFP_KERNEL, + netdev_queue_numa_node_read(dev_queue)); + + if (!p) + goto errout; + sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); + /* if we got non aligned memory, ask more and do alignment ourself */ + if (sch != p) { + kfree(p); + p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL, + netdev_queue_numa_node_read(dev_queue)); + if (!p) + goto errout; + sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); + sch->padded = (char *) sch - (char *) p; + } + INIT_LIST_HEAD(&sch->list); + skb_queue_head_init(&sch->q); + + spin_lock_init(&sch->busylock); + lockdep_set_class(&sch->busylock, + dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); + + sch->ops = ops; + sch->enqueue = ops->enqueue; + sch->dequeue = ops->dequeue; + sch->dev_queue = dev_queue; + dev_hold(dev); + atomic_set(&sch->refcnt, 1); + + return sch; +errout: + return ERR_PTR(err); +} + +struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue, + const struct Qdisc_ops *ops, + unsigned int parentid) +{ + struct Qdisc *sch; + + if (!try_module_get(ops->owner)) + goto errout; + + sch = qdisc_alloc(dev_queue, ops); + if (IS_ERR(sch)) + goto errout; + sch->parent = parentid; + + if (!ops->init || ops->init(sch, NULL) == 0) + return sch; + + qdisc_destroy(sch); +errout: + return NULL; +} +EXPORT_SYMBOL(qdisc_create_dflt); + +/* Under qdisc_lock(qdisc) and BH! */ + +void qdisc_reset(struct Qdisc *qdisc) +{ + const struct Qdisc_ops *ops = qdisc->ops; + + if (ops->reset) + ops->reset(qdisc); + + if (qdisc->gso_skb) { + kfree_skb_list(qdisc->gso_skb); + qdisc->gso_skb = NULL; + qdisc->q.qlen = 0; + } +} +EXPORT_SYMBOL(qdisc_reset); + +static void qdisc_rcu_free(struct rcu_head *head) +{ + struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head); + + if (qdisc_is_percpu_stats(qdisc)) + free_percpu(qdisc->cpu_bstats); + + kfree((char *) qdisc - qdisc->padded); +} + +void qdisc_destroy(struct Qdisc *qdisc) +{ + const struct Qdisc_ops *ops = qdisc->ops; + + if (qdisc->flags & TCQ_F_BUILTIN || + !atomic_dec_and_test(&qdisc->refcnt)) + return; + +#ifdef CONFIG_NET_SCHED + qdisc_list_del(qdisc); + + qdisc_put_stab(rtnl_dereference(qdisc->stab)); +#endif + gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est); + if (ops->reset) + ops->reset(qdisc); + if (ops->destroy) + ops->destroy(qdisc); + + module_put(ops->owner); + dev_put(qdisc_dev(qdisc)); + + kfree_skb_list(qdisc->gso_skb); + /* + * gen_estimator est_timer() might access qdisc->q.lock, + * wait a RCU grace period before freeing qdisc. + */ + call_rcu(&qdisc->rcu_head, qdisc_rcu_free); +} +EXPORT_SYMBOL(qdisc_destroy); + +/* Attach toplevel qdisc to device queue. */ +struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue, + struct Qdisc *qdisc) +{ + struct Qdisc *oqdisc = dev_queue->qdisc_sleeping; + spinlock_t *root_lock; + + root_lock = qdisc_lock(oqdisc); + spin_lock_bh(root_lock); + + /* Prune old scheduler */ + if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1) + qdisc_reset(oqdisc); + + /* ... and graft new one */ + if (qdisc == NULL) + qdisc = &noop_qdisc; + dev_queue->qdisc_sleeping = qdisc; + rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc); + + spin_unlock_bh(root_lock); + + return oqdisc; +} +EXPORT_SYMBOL(dev_graft_qdisc); + +static void attach_one_default_qdisc(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_unused) +{ + struct Qdisc *qdisc = &noqueue_qdisc; + + if (dev->tx_queue_len) { + qdisc = qdisc_create_dflt(dev_queue, + default_qdisc_ops, TC_H_ROOT); + if (!qdisc) { + netdev_info(dev, "activation failed\n"); + return; + } + if (!netif_is_multiqueue(dev)) + qdisc->flags |= TCQ_F_ONETXQUEUE; + } + dev_queue->qdisc_sleeping = qdisc; +} + +static void attach_default_qdiscs(struct net_device *dev) +{ + struct netdev_queue *txq; + struct Qdisc *qdisc; + + txq = netdev_get_tx_queue(dev, 0); + + if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) { + netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL); + dev->qdisc = txq->qdisc_sleeping; + atomic_inc(&dev->qdisc->refcnt); + } else { + qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT); + if (qdisc) { + dev->qdisc = qdisc; + qdisc->ops->attach(qdisc); + } + } +} + +static void transition_one_qdisc(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_need_watchdog) +{ + struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping; + int *need_watchdog_p = _need_watchdog; + + if (!(new_qdisc->flags & TCQ_F_BUILTIN)) + clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state); + + rcu_assign_pointer(dev_queue->qdisc, new_qdisc); + if (need_watchdog_p && new_qdisc != &noqueue_qdisc) { + dev_queue->trans_start = 0; + *need_watchdog_p = 1; + } +} + +void dev_activate(struct net_device *dev) +{ + int need_watchdog; + + /* No queueing discipline is attached to device; + * create default one for devices, which need queueing + * and noqueue_qdisc for virtual interfaces + */ + + if (dev->qdisc == &noop_qdisc) + attach_default_qdiscs(dev); + + if (!netif_carrier_ok(dev)) + /* Delay activation until next carrier-on event */ + return; + + need_watchdog = 0; + netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog); + if (dev_ingress_queue(dev)) + transition_one_qdisc(dev, dev_ingress_queue(dev), NULL); + + if (need_watchdog) { + dev->trans_start = jiffies; + dev_watchdog_up(dev); + } +} +EXPORT_SYMBOL(dev_activate); + +static void dev_deactivate_queue(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_qdisc_default) +{ + struct Qdisc *qdisc_default = _qdisc_default; + struct Qdisc *qdisc; + + qdisc = rtnl_dereference(dev_queue->qdisc); + if (qdisc) { + spin_lock_bh(qdisc_lock(qdisc)); + + if (!(qdisc->flags & TCQ_F_BUILTIN)) + set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state); + + rcu_assign_pointer(dev_queue->qdisc, qdisc_default); + qdisc_reset(qdisc); + + spin_unlock_bh(qdisc_lock(qdisc)); + } +} + +static bool some_qdisc_is_busy(struct net_device *dev) +{ + unsigned int i; + + for (i = 0; i < dev->num_tx_queues; i++) { + struct netdev_queue *dev_queue; + spinlock_t *root_lock; + struct Qdisc *q; + int val; + + dev_queue = netdev_get_tx_queue(dev, i); + q = dev_queue->qdisc_sleeping; + root_lock = qdisc_lock(q); + + spin_lock_bh(root_lock); + + val = (qdisc_is_running(q) || + test_bit(__QDISC_STATE_SCHED, &q->state)); + + spin_unlock_bh(root_lock); + + if (val) + return true; + } + return false; +} + +/** + * dev_deactivate_many - deactivate transmissions on several devices + * @head: list of devices to deactivate + * + * This function returns only when all outstanding transmissions + * have completed, unless all devices are in dismantle phase. + */ +void dev_deactivate_many(struct list_head *head) +{ + struct net_device *dev; + bool sync_needed = false; + + list_for_each_entry(dev, head, close_list) { + netdev_for_each_tx_queue(dev, dev_deactivate_queue, + &noop_qdisc); + if (dev_ingress_queue(dev)) + dev_deactivate_queue(dev, dev_ingress_queue(dev), + &noop_qdisc); + + dev_watchdog_down(dev); + sync_needed |= !dev->dismantle; + } + + /* Wait for outstanding qdisc-less dev_queue_xmit calls. + * This is avoided if all devices are in dismantle phase : + * Caller will call synchronize_net() for us + */ + if (sync_needed) + synchronize_net(); + + /* Wait for outstanding qdisc_run calls. */ + list_for_each_entry(dev, head, close_list) + while (some_qdisc_is_busy(dev)) + msleep(1); +} + +void dev_deactivate(struct net_device *dev) +{ + LIST_HEAD(single); + + list_add(&dev->close_list, &single); + dev_deactivate_many(&single); + list_del(&single); +} +EXPORT_SYMBOL(dev_deactivate); + +static void dev_init_scheduler_queue(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_qdisc) +{ + struct Qdisc *qdisc = _qdisc; + + rcu_assign_pointer(dev_queue->qdisc, qdisc); + dev_queue->qdisc_sleeping = qdisc; +} + +void dev_init_scheduler(struct net_device *dev) +{ + dev->qdisc = &noop_qdisc; + netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc); + if (dev_ingress_queue(dev)) + dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc); + + setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev); +} + +static void shutdown_scheduler_queue(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_qdisc_default) +{ + struct Qdisc *qdisc = dev_queue->qdisc_sleeping; + struct Qdisc *qdisc_default = _qdisc_default; + + if (qdisc) { + rcu_assign_pointer(dev_queue->qdisc, qdisc_default); + dev_queue->qdisc_sleeping = qdisc_default; + + qdisc_destroy(qdisc); + } +} + +void dev_shutdown(struct net_device *dev) +{ + netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc); + if (dev_ingress_queue(dev)) + shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc); + qdisc_destroy(dev->qdisc); + dev->qdisc = &noop_qdisc; + + WARN_ON(timer_pending(&dev->watchdog_timer)); +} + +void psched_ratecfg_precompute(struct psched_ratecfg *r, + const struct tc_ratespec *conf, + u64 rate64) +{ + memset(r, 0, sizeof(*r)); + r->overhead = conf->overhead; + r->rate_bytes_ps = max_t(u64, conf->rate, rate64); + r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK); + r->mult = 1; + /* + * The deal here is to replace a divide by a reciprocal one + * in fast path (a reciprocal divide is a multiply and a shift) + * + * Normal formula would be : + * time_in_ns = (NSEC_PER_SEC * len) / rate_bps + * + * We compute mult/shift to use instead : + * time_in_ns = (len * mult) >> shift; + * + * We try to get the highest possible mult value for accuracy, + * but have to make sure no overflows will ever happen. + */ + if (r->rate_bytes_ps > 0) { + u64 factor = NSEC_PER_SEC; + + for (;;) { + r->mult = div64_u64(factor, r->rate_bytes_ps); + if (r->mult & (1U << 31) || factor & (1ULL << 63)) + break; + factor <<= 1; + r->shift++; + } + } +} +EXPORT_SYMBOL(psched_ratecfg_precompute); |