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-rw-r--r--net/sched/sch_generic.c1482
1 files changed, 1482 insertions, 0 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
new file mode 100644
index 000000000..ecdd9e83f
--- /dev/null
+++ b/net/sched/sch_generic.c
@@ -0,0 +1,1482 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/sched/sch_generic.c Generic packet scheduler routines.
+ *
+ * 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 <linux/skb_array.h>
+#include <linux/if_macvlan.h>
+#include <net/sch_generic.h>
+#include <net/pkt_sched.h>
+#include <net/dst.h>
+#include <trace/events/qdisc.h>
+#include <trace/events/net.h>
+#include <net/xfrm.h>
+
+/* Qdisc to use by default */
+const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
+EXPORT_SYMBOL(default_qdisc_ops);
+
+static void qdisc_maybe_clear_missed(struct Qdisc *q,
+ const struct netdev_queue *txq)
+{
+ clear_bit(__QDISC_STATE_MISSED, &q->state);
+
+ /* Make sure the below netif_xmit_frozen_or_stopped()
+ * checking happens after clearing STATE_MISSED.
+ */
+ smp_mb__after_atomic();
+
+ /* Checking netif_xmit_frozen_or_stopped() again to
+ * make sure STATE_MISSED is set if the STATE_MISSED
+ * set by netif_tx_wake_queue()'s rescheduling of
+ * net_tx_action() is cleared by the above clear_bit().
+ */
+ if (!netif_xmit_frozen_or_stopped(txq))
+ set_bit(__QDISC_STATE_MISSED, &q->state);
+}
+
+/* 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.
+ */
+
+#define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
+
+static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
+{
+ const struct netdev_queue *txq = q->dev_queue;
+ spinlock_t *lock = NULL;
+ struct sk_buff *skb;
+
+ if (q->flags & TCQ_F_NOLOCK) {
+ lock = qdisc_lock(q);
+ spin_lock(lock);
+ }
+
+ skb = skb_peek(&q->skb_bad_txq);
+ if (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)) {
+ skb = __skb_dequeue(&q->skb_bad_txq);
+ if (qdisc_is_percpu_stats(q)) {
+ qdisc_qstats_cpu_backlog_dec(q, skb);
+ qdisc_qstats_cpu_qlen_dec(q);
+ } else {
+ qdisc_qstats_backlog_dec(q, skb);
+ q->q.qlen--;
+ }
+ } else {
+ skb = SKB_XOFF_MAGIC;
+ qdisc_maybe_clear_missed(q, txq);
+ }
+ }
+
+ if (lock)
+ spin_unlock(lock);
+
+ return skb;
+}
+
+static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
+{
+ struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
+
+ if (unlikely(skb))
+ skb = __skb_dequeue_bad_txq(q);
+
+ return skb;
+}
+
+static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
+ struct sk_buff *skb)
+{
+ spinlock_t *lock = NULL;
+
+ if (q->flags & TCQ_F_NOLOCK) {
+ lock = qdisc_lock(q);
+ spin_lock(lock);
+ }
+
+ __skb_queue_tail(&q->skb_bad_txq, skb);
+
+ if (qdisc_is_percpu_stats(q)) {
+ qdisc_qstats_cpu_backlog_inc(q, skb);
+ qdisc_qstats_cpu_qlen_inc(q);
+ } else {
+ qdisc_qstats_backlog_inc(q, skb);
+ q->q.qlen++;
+ }
+
+ if (lock)
+ spin_unlock(lock);
+}
+
+static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
+{
+ spinlock_t *lock = NULL;
+
+ if (q->flags & TCQ_F_NOLOCK) {
+ lock = qdisc_lock(q);
+ spin_lock(lock);
+ }
+
+ while (skb) {
+ struct sk_buff *next = skb->next;
+
+ __skb_queue_tail(&q->gso_skb, skb);
+
+ /* it's still part of the queue */
+ if (qdisc_is_percpu_stats(q)) {
+ qdisc_qstats_cpu_requeues_inc(q);
+ qdisc_qstats_cpu_backlog_inc(q, skb);
+ qdisc_qstats_cpu_qlen_inc(q);
+ } else {
+ q->qstats.requeues++;
+ qdisc_qstats_backlog_inc(q, skb);
+ q->q.qlen++;
+ }
+
+ skb = next;
+ }
+ if (lock)
+ spin_unlock(lock);
+ __netif_schedule(q);
+}
+
+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_mark_not_on_list(skb);
+}
+
+/* This variant of try_bulk_dequeue_skb() makes sure
+ * all skbs in the chain are for the same txq
+ */
+static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
+ struct sk_buff *skb,
+ int *packets)
+{
+ int mapping = skb_get_queue_mapping(skb);
+ struct sk_buff *nskb;
+ int cnt = 0;
+
+ do {
+ nskb = q->dequeue(q);
+ if (!nskb)
+ break;
+ if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
+ qdisc_enqueue_skb_bad_txq(q, nskb);
+ break;
+ }
+ skb->next = nskb;
+ skb = nskb;
+ } while (++cnt < 8);
+ (*packets) += cnt;
+ skb_mark_not_on_list(skb);
+}
+
+/* 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)
+{
+ const struct netdev_queue *txq = q->dev_queue;
+ struct sk_buff *skb = NULL;
+
+ *packets = 1;
+ if (unlikely(!skb_queue_empty(&q->gso_skb))) {
+ spinlock_t *lock = NULL;
+
+ if (q->flags & TCQ_F_NOLOCK) {
+ lock = qdisc_lock(q);
+ spin_lock(lock);
+ }
+
+ skb = skb_peek(&q->gso_skb);
+
+ /* skb may be null if another cpu pulls gso_skb off in between
+ * empty check and lock.
+ */
+ if (!skb) {
+ if (lock)
+ spin_unlock(lock);
+ goto validate;
+ }
+
+ /* skb in gso_skb were already validated */
+ *validate = false;
+ if (xfrm_offload(skb))
+ *validate = true;
+ /* check the reason of requeuing without tx lock first */
+ txq = skb_get_tx_queue(txq->dev, skb);
+ if (!netif_xmit_frozen_or_stopped(txq)) {
+ skb = __skb_dequeue(&q->gso_skb);
+ if (qdisc_is_percpu_stats(q)) {
+ qdisc_qstats_cpu_backlog_dec(q, skb);
+ qdisc_qstats_cpu_qlen_dec(q);
+ } else {
+ qdisc_qstats_backlog_dec(q, skb);
+ q->q.qlen--;
+ }
+ } else {
+ skb = NULL;
+ qdisc_maybe_clear_missed(q, txq);
+ }
+ if (lock)
+ spin_unlock(lock);
+ goto trace;
+ }
+validate:
+ *validate = true;
+
+ if ((q->flags & TCQ_F_ONETXQUEUE) &&
+ netif_xmit_frozen_or_stopped(txq)) {
+ qdisc_maybe_clear_missed(q, txq);
+ return skb;
+ }
+
+ skb = qdisc_dequeue_skb_bad_txq(q);
+ if (unlikely(skb)) {
+ if (skb == SKB_XOFF_MAGIC)
+ return NULL;
+ goto bulk;
+ }
+ skb = q->dequeue(q);
+ if (skb) {
+bulk:
+ if (qdisc_may_bulk(q))
+ try_bulk_dequeue_skb(q, skb, txq, packets);
+ else
+ try_bulk_dequeue_skb_slow(q, skb, packets);
+ }
+trace:
+ trace_qdisc_dequeue(q, txq, *packets, skb);
+ return skb;
+}
+
+/*
+ * Transmit possibly several skbs, and handle the return status as
+ * required. Owning running seqcount bit guarantees that
+ * only one CPU can execute this function.
+ *
+ * Returns to the caller:
+ * false - hardware queue frozen backoff
+ * true - feel free to send more pkts
+ */
+bool 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;
+ bool again = false;
+
+ /* And release qdisc */
+ if (root_lock)
+ spin_unlock(root_lock);
+
+ /* Note that we validate skb (GSO, checksum, ...) outside of locks */
+ if (validate)
+ skb = validate_xmit_skb_list(skb, dev, &again);
+
+#ifdef CONFIG_XFRM_OFFLOAD
+ if (unlikely(again)) {
+ if (root_lock)
+ spin_lock(root_lock);
+
+ dev_requeue_skb(skb, q);
+ return false;
+ }
+#endif
+
+ if (likely(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);
+ else
+ qdisc_maybe_clear_missed(q, txq);
+
+ HARD_TX_UNLOCK(dev, txq);
+ } else {
+ if (root_lock)
+ spin_lock(root_lock);
+ return true;
+ }
+
+ if (root_lock)
+ spin_lock(root_lock);
+
+ if (!dev_xmit_complete(ret)) {
+ /* 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);
+
+ dev_requeue_skb(skb, q);
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * NOTE: Called under qdisc_lock(q) with locally disabled BH.
+ *
+ * running seqcount 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 bool qdisc_restart(struct Qdisc *q, int *packets)
+{
+ spinlock_t *root_lock = NULL;
+ struct netdev_queue *txq;
+ struct net_device *dev;
+ struct sk_buff *skb;
+ bool validate;
+
+ /* Dequeue packet */
+ skb = dequeue_skb(q, &validate, packets);
+ if (unlikely(!skb))
+ return false;
+
+ if (!(q->flags & TCQ_F_NOLOCK))
+ 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 = READ_ONCE(dev_tx_weight);
+ int packets;
+
+ while (qdisc_restart(q, &packets)) {
+ quota -= packets;
+ if (quota <= 0) {
+ __netif_schedule(q);
+ break;
+ }
+ }
+}
+
+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);
+ else if (netif_is_macvlan(dev))
+ dev = macvlan_dev_real_dev(dev);
+ res = netdev_get_tx_queue(dev, 0)->trans_start;
+ for (i = 1; i < dev->num_tx_queues; i++) {
+ val = netdev_get_tx_queue(dev, i)->trans_start;
+ if (val && time_after(val, res))
+ res = val;
+ }
+
+ return res;
+}
+EXPORT_SYMBOL(dev_trans_start);
+
+static void dev_watchdog(struct timer_list *t)
+{
+ struct net_device *dev = from_timer(dev, t, watchdog_timer);
+
+ 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);
+ trans_start = txq->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) {
+ trace_net_dev_xmit_timeout(dev, i);
+ 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, i);
+ }
+ 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);
+ }
+}
+EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
+
+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 acquisition of 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_up_count);
+ 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_down_count);
+ 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,
+ struct sk_buff **to_free)
+{
+ __qdisc_drop(skb, to_free);
+ 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 = {
+ RCU_POINTER_INITIALIZER(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,
+ .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
+ .dev_queue = &noop_netdev_queue,
+ .running = SEQCNT_ZERO(noop_qdisc.running),
+ .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
+ .gso_skb = {
+ .next = (struct sk_buff *)&noop_qdisc.gso_skb,
+ .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
+ .qlen = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
+ },
+ .skb_bad_txq = {
+ .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
+ .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
+ .qlen = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
+ },
+};
+EXPORT_SYMBOL(noop_qdisc);
+
+static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
+ struct netlink_ext_ack *extack)
+{
+ /* register_qdisc() assigns a default of noop_enqueue if unset,
+ * but __dev_queue_xmit() treats noqueue only as such
+ * if this is NULL - so clear it here. */
+ qdisc->enqueue = NULL;
+ return 0;
+}
+
+struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
+ .id = "noqueue",
+ .priv_size = 0,
+ .init = noqueue_init,
+ .enqueue = noop_enqueue,
+ .dequeue = noop_dequeue,
+ .peek = noop_dequeue,
+ .owner = THIS_MODULE,
+};
+
+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:
+ * - rings for priority bands
+ */
+struct pfifo_fast_priv {
+ struct skb_array q[PFIFO_FAST_BANDS];
+};
+
+static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
+ int band)
+{
+ return &priv->q[band];
+}
+
+static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
+ struct sk_buff **to_free)
+{
+ int band = prio2band[skb->priority & TC_PRIO_MAX];
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ struct skb_array *q = band2list(priv, band);
+ unsigned int pkt_len = qdisc_pkt_len(skb);
+ int err;
+
+ err = skb_array_produce(q, skb);
+
+ if (unlikely(err)) {
+ if (qdisc_is_percpu_stats(qdisc))
+ return qdisc_drop_cpu(skb, qdisc, to_free);
+ else
+ return qdisc_drop(skb, qdisc, to_free);
+ }
+
+ qdisc_update_stats_at_enqueue(qdisc, pkt_len);
+ return NET_XMIT_SUCCESS;
+}
+
+static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
+{
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ struct sk_buff *skb = NULL;
+ bool need_retry = true;
+ int band;
+
+retry:
+ for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
+ struct skb_array *q = band2list(priv, band);
+
+ if (__skb_array_empty(q))
+ continue;
+
+ skb = __skb_array_consume(q);
+ }
+ if (likely(skb)) {
+ qdisc_update_stats_at_dequeue(qdisc, skb);
+ } else if (need_retry &&
+ test_bit(__QDISC_STATE_MISSED, &qdisc->state)) {
+ /* Delay clearing the STATE_MISSED here to reduce
+ * the overhead of the second spin_trylock() in
+ * qdisc_run_begin() and __netif_schedule() calling
+ * in qdisc_run_end().
+ */
+ clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
+
+ /* Make sure dequeuing happens after clearing
+ * STATE_MISSED.
+ */
+ smp_mb__after_atomic();
+
+ need_retry = false;
+
+ goto retry;
+ } else {
+ WRITE_ONCE(qdisc->empty, true);
+ }
+
+ return skb;
+}
+
+static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
+{
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ struct sk_buff *skb = NULL;
+ int band;
+
+ for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
+ struct skb_array *q = band2list(priv, band);
+
+ skb = __skb_array_peek(q);
+ }
+
+ return skb;
+}
+
+static void pfifo_fast_reset(struct Qdisc *qdisc)
+{
+ int i, band;
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+
+ for (band = 0; band < PFIFO_FAST_BANDS; band++) {
+ struct skb_array *q = band2list(priv, band);
+ struct sk_buff *skb;
+
+ /* NULL ring is possible if destroy path is due to a failed
+ * skb_array_init() in pfifo_fast_init() case.
+ */
+ if (!q->ring.queue)
+ continue;
+
+ while ((skb = __skb_array_consume(q)) != NULL)
+ kfree_skb(skb);
+ }
+
+ if (qdisc_is_percpu_stats(qdisc)) {
+ for_each_possible_cpu(i) {
+ struct gnet_stats_queue *q;
+
+ q = per_cpu_ptr(qdisc->cpu_qstats, i);
+ q->backlog = 0;
+ 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,
+ struct netlink_ext_ack *extack)
+{
+ unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ int prio;
+
+ /* guard against zero length rings */
+ if (!qlen)
+ return -EINVAL;
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+ struct skb_array *q = band2list(priv, prio);
+ int err;
+
+ err = skb_array_init(q, qlen, GFP_KERNEL);
+ if (err)
+ return -ENOMEM;
+ }
+
+ /* Can by-pass the queue discipline */
+ qdisc->flags |= TCQ_F_CAN_BYPASS;
+ return 0;
+}
+
+static void pfifo_fast_destroy(struct Qdisc *sch)
+{
+ struct pfifo_fast_priv *priv = qdisc_priv(sch);
+ int prio;
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+ struct skb_array *q = band2list(priv, prio);
+
+ /* NULL ring is possible if destroy path is due to a failed
+ * skb_array_init() in pfifo_fast_init() case.
+ */
+ if (!q->ring.queue)
+ continue;
+ /* Destroy ring but no need to kfree_skb because a call to
+ * pfifo_fast_reset() has already done that work.
+ */
+ ptr_ring_cleanup(&q->ring, NULL);
+ }
+}
+
+static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
+ unsigned int new_len)
+{
+ struct pfifo_fast_priv *priv = qdisc_priv(sch);
+ struct skb_array *bands[PFIFO_FAST_BANDS];
+ int prio;
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+ struct skb_array *q = band2list(priv, prio);
+
+ bands[prio] = q;
+ }
+
+ return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
+ GFP_KERNEL);
+}
+
+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,
+ .destroy = pfifo_fast_destroy,
+ .reset = pfifo_fast_reset,
+ .dump = pfifo_fast_dump,
+ .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
+ .owner = THIS_MODULE,
+ .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
+};
+EXPORT_SYMBOL(pfifo_fast_ops);
+
+static struct lock_class_key qdisc_tx_busylock;
+static struct lock_class_key qdisc_running_key;
+
+struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
+ const struct Qdisc_ops *ops,
+ struct netlink_ext_ack *extack)
+{
+ struct Qdisc *sch;
+ unsigned int size = sizeof(*sch) + ops->priv_size;
+ int err = -ENOBUFS;
+ struct net_device *dev;
+
+ if (!dev_queue) {
+ NL_SET_ERR_MSG(extack, "No device queue given");
+ err = -EINVAL;
+ goto errout;
+ }
+
+ dev = dev_queue->dev;
+ sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
+
+ if (!sch)
+ goto errout;
+ __skb_queue_head_init(&sch->gso_skb);
+ __skb_queue_head_init(&sch->skb_bad_txq);
+ qdisc_skb_head_init(&sch->q);
+ spin_lock_init(&sch->q.lock);
+
+ if (ops->static_flags & TCQ_F_CPUSTATS) {
+ sch->cpu_bstats =
+ netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
+ if (!sch->cpu_bstats)
+ goto errout1;
+
+ sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
+ if (!sch->cpu_qstats) {
+ free_percpu(sch->cpu_bstats);
+ goto errout1;
+ }
+ }
+
+ spin_lock_init(&sch->busylock);
+ lockdep_set_class(&sch->busylock,
+ dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+
+ /* seqlock has the same scope of busylock, for NOLOCK qdisc */
+ spin_lock_init(&sch->seqlock);
+ lockdep_set_class(&sch->seqlock,
+ dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+
+ seqcount_init(&sch->running);
+ lockdep_set_class(&sch->running,
+ dev->qdisc_running_key ?: &qdisc_running_key);
+
+ sch->ops = ops;
+ sch->flags = ops->static_flags;
+ sch->enqueue = ops->enqueue;
+ sch->dequeue = ops->dequeue;
+ sch->dev_queue = dev_queue;
+ sch->empty = true;
+ dev_hold(dev);
+ refcount_set(&sch->refcnt, 1);
+
+ return sch;
+errout1:
+ kfree(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 netlink_ext_ack *extack)
+{
+ struct Qdisc *sch;
+
+ if (!try_module_get(ops->owner)) {
+ NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
+ return NULL;
+ }
+
+ sch = qdisc_alloc(dev_queue, ops, extack);
+ if (IS_ERR(sch)) {
+ module_put(ops->owner);
+ return NULL;
+ }
+ sch->parent = parentid;
+
+ if (!ops->init || ops->init(sch, NULL, extack) == 0) {
+ trace_qdisc_create(ops, dev_queue->dev, parentid);
+ return sch;
+ }
+
+ qdisc_put(sch);
+ 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;
+ struct sk_buff *skb, *tmp;
+
+ trace_qdisc_reset(qdisc);
+
+ if (ops->reset)
+ ops->reset(qdisc);
+
+ skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
+ __skb_unlink(skb, &qdisc->gso_skb);
+ kfree_skb_list(skb);
+ }
+
+ skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
+ __skb_unlink(skb, &qdisc->skb_bad_txq);
+ kfree_skb_list(skb);
+ }
+
+ qdisc->q.qlen = 0;
+ qdisc->qstats.backlog = 0;
+}
+EXPORT_SYMBOL(qdisc_reset);
+
+void qdisc_free(struct Qdisc *qdisc)
+{
+ if (qdisc_is_percpu_stats(qdisc)) {
+ free_percpu(qdisc->cpu_bstats);
+ free_percpu(qdisc->cpu_qstats);
+ }
+
+ kfree(qdisc);
+}
+
+static void qdisc_free_cb(struct rcu_head *head)
+{
+ struct Qdisc *q = container_of(head, struct Qdisc, rcu);
+
+ qdisc_free(q);
+}
+
+static void qdisc_destroy(struct Qdisc *qdisc)
+{
+ const struct Qdisc_ops *ops = qdisc->ops;
+
+#ifdef CONFIG_NET_SCHED
+ qdisc_hash_del(qdisc);
+
+ qdisc_put_stab(rtnl_dereference(qdisc->stab));
+#endif
+ gen_kill_estimator(&qdisc->rate_est);
+
+ qdisc_reset(qdisc);
+
+ if (ops->destroy)
+ ops->destroy(qdisc);
+
+ module_put(ops->owner);
+ dev_put(qdisc_dev(qdisc));
+
+ trace_qdisc_destroy(qdisc);
+
+ call_rcu(&qdisc->rcu, qdisc_free_cb);
+}
+
+void qdisc_put(struct Qdisc *qdisc)
+{
+ if (!qdisc)
+ return;
+
+ if (qdisc->flags & TCQ_F_BUILTIN ||
+ !refcount_dec_and_test(&qdisc->refcnt))
+ return;
+
+ qdisc_destroy(qdisc);
+}
+EXPORT_SYMBOL(qdisc_put);
+
+/* Version of qdisc_put() that is called with rtnl mutex unlocked.
+ * Intended to be used as optimization, this function only takes rtnl lock if
+ * qdisc reference counter reached zero.
+ */
+
+void qdisc_put_unlocked(struct Qdisc *qdisc)
+{
+ if (qdisc->flags & TCQ_F_BUILTIN ||
+ !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
+ return;
+
+ qdisc_destroy(qdisc);
+ rtnl_unlock();
+}
+EXPORT_SYMBOL(qdisc_put_unlocked);
+
+/* 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);
+
+ /* ... 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 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_put(qdisc);
+ }
+}
+
+static void attach_one_default_qdisc(struct net_device *dev,
+ struct netdev_queue *dev_queue,
+ void *_unused)
+{
+ struct Qdisc *qdisc;
+ const struct Qdisc_ops *ops = default_qdisc_ops;
+
+ if (dev->priv_flags & IFF_NO_QUEUE)
+ ops = &noqueue_qdisc_ops;
+ else if(dev->type == ARPHRD_CAN)
+ ops = &pfifo_fast_ops;
+
+ qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
+ if (!qdisc)
+ return;
+
+ if (!netif_is_multiqueue(dev))
+ qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
+ 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->priv_flags & IFF_NO_QUEUE) {
+ netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+ qdisc = txq->qdisc_sleeping;
+ rcu_assign_pointer(dev->qdisc, qdisc);
+ qdisc_refcount_inc(qdisc);
+ } else {
+ qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
+ if (qdisc) {
+ rcu_assign_pointer(dev->qdisc, qdisc);
+ qdisc->ops->attach(qdisc);
+ }
+ }
+ qdisc = rtnl_dereference(dev->qdisc);
+
+ /* Detect default qdisc setup/init failed and fallback to "noqueue" */
+ if (qdisc == &noop_qdisc) {
+ netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
+ default_qdisc_ops->id, noqueue_qdisc_ops.id);
+ netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
+ dev->priv_flags |= IFF_NO_QUEUE;
+ netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+ qdisc = txq->qdisc_sleeping;
+ rcu_assign_pointer(dev->qdisc, qdisc);
+ qdisc_refcount_inc(qdisc);
+ dev->priv_flags ^= IFF_NO_QUEUE;
+ }
+
+#ifdef CONFIG_NET_SCHED
+ if (qdisc != &noop_qdisc)
+ qdisc_hash_add(qdisc, false);
+#endif
+}
+
+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) {
+ 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 (rtnl_dereference(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) {
+ netif_trans_update(dev);
+ dev_watchdog_up(dev);
+ }
+}
+EXPORT_SYMBOL(dev_activate);
+
+static void qdisc_deactivate(struct Qdisc *qdisc)
+{
+ if (qdisc->flags & TCQ_F_BUILTIN)
+ return;
+
+ set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
+}
+
+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) {
+ qdisc_deactivate(qdisc);
+ rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
+ }
+}
+
+static void dev_reset_queue(struct net_device *dev,
+ struct netdev_queue *dev_queue,
+ void *_unused)
+{
+ struct Qdisc *qdisc;
+ bool nolock;
+
+ qdisc = dev_queue->qdisc_sleeping;
+ if (!qdisc)
+ return;
+
+ nolock = qdisc->flags & TCQ_F_NOLOCK;
+
+ if (nolock)
+ spin_lock_bh(&qdisc->seqlock);
+ spin_lock_bh(qdisc_lock(qdisc));
+
+ qdisc_reset(qdisc);
+
+ spin_unlock_bh(qdisc_lock(qdisc));
+ if (nolock) {
+ clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
+ spin_unlock_bh(&qdisc->seqlock);
+ }
+}
+
+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;
+
+ 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);
+ }
+
+ /* Wait for outstanding qdisc-less dev_queue_xmit calls or
+ * outstanding qdisc enqueuing calls.
+ * This is avoided if all devices are in dismantle phase :
+ * Caller will call synchronize_net() for us
+ */
+ synchronize_net();
+
+ list_for_each_entry(dev, head, close_list) {
+ netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
+
+ if (dev_ingress_queue(dev))
+ dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
+ }
+
+ /* Wait for outstanding qdisc_run calls. */
+ list_for_each_entry(dev, head, close_list) {
+ while (some_qdisc_is_busy(dev)) {
+ /* wait_event() would avoid this sleep-loop but would
+ * require expensive checks in the fast paths of packet
+ * processing which isn't worth it.
+ */
+ schedule_timeout_uninterruptible(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 int qdisc_change_tx_queue_len(struct net_device *dev,
+ struct netdev_queue *dev_queue)
+{
+ struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
+ const struct Qdisc_ops *ops = qdisc->ops;
+
+ if (ops->change_tx_queue_len)
+ return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
+ return 0;
+}
+
+void dev_qdisc_change_real_num_tx(struct net_device *dev,
+ unsigned int new_real_tx)
+{
+ struct Qdisc *qdisc = rtnl_dereference(dev->qdisc);
+
+ if (qdisc->ops->change_real_num_tx)
+ qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
+}
+
+int dev_qdisc_change_tx_queue_len(struct net_device *dev)
+{
+ bool up = dev->flags & IFF_UP;
+ unsigned int i;
+ int ret = 0;
+
+ if (up)
+ dev_deactivate(dev);
+
+ for (i = 0; i < dev->num_tx_queues; i++) {
+ ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
+
+ /* TODO: revert changes on a partial failure */
+ if (ret)
+ break;
+ }
+
+ if (up)
+ dev_activate(dev);
+ return ret;
+}
+
+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)
+{
+ rcu_assign_pointer(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);
+
+ timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
+}
+
+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_put(rtnl_dereference(dev->qdisc));
+ rcu_assign_pointer(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->mpu = conf->mpu;
+ 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);
+
+static void mini_qdisc_rcu_func(struct rcu_head *head)
+{
+}
+
+void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
+ struct tcf_proto *tp_head)
+{
+ /* Protected with chain0->filter_chain_lock.
+ * Can't access chain directly because tp_head can be NULL.
+ */
+ struct mini_Qdisc *miniq_old =
+ rcu_dereference_protected(*miniqp->p_miniq, 1);
+ struct mini_Qdisc *miniq;
+
+ if (!tp_head) {
+ RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
+ /* Wait for flying RCU callback before it is freed. */
+ rcu_barrier();
+ return;
+ }
+
+ miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
+ &miniqp->miniq1 : &miniqp->miniq2;
+
+ /* We need to make sure that readers won't see the miniq
+ * we are about to modify. So wait until previous call_rcu callback
+ * is done.
+ */
+ rcu_barrier();
+ miniq->filter_list = tp_head;
+ rcu_assign_pointer(*miniqp->p_miniq, miniq);
+
+ if (miniq_old)
+ /* This is counterpart of the rcu barriers above. We need to
+ * block potential new user of miniq_old until all readers
+ * are not seeing it.
+ */
+ call_rcu(&miniq_old->rcu, mini_qdisc_rcu_func);
+}
+EXPORT_SYMBOL(mini_qdisc_pair_swap);
+
+void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
+ struct tcf_block *block)
+{
+ miniqp->miniq1.block = block;
+ miniqp->miniq2.block = block;
+}
+EXPORT_SYMBOL(mini_qdisc_pair_block_init);
+
+void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
+ struct mini_Qdisc __rcu **p_miniq)
+{
+ miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
+ miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
+ miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
+ miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
+ miniqp->p_miniq = p_miniq;
+}
+EXPORT_SYMBOL(mini_qdisc_pair_init);