--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff