Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2389 insertions, 0 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
new file mode 100644
index 000000000..e8f988e1c
--- /dev/null
+++ b/net/sched/sch_api.c
@@ -0,0 +1,2389 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/sched/sch_api.c	Packet scheduler API.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ * Fixes:
+ *
+ * Rani Assaf <rani@magic.metawire.com> :980802: JIFFIES and CPU clock sources are repaired.
+ * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
+ * Jamal Hadi Salim <hadi@nortelnetworks.com>: 990601: ingress support
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kmod.h>
+#include <linux/list.h>
+#include <linux/hrtimer.h>
+#include <linux/slab.h>
+#include <linux/hashtable.h>
+
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
+
+#include <trace/events/qdisc.h>
+
+/*
+
+   Short review.
+   -------------
+
+   This file consists of two interrelated parts:
+
+   1. queueing disciplines manager frontend.
+   2. traffic classes manager frontend.
+
+   Generally, queueing discipline ("qdisc") is a black box,
+   which is able to enqueue packets and to dequeue them (when
+   device is ready to send something) in order and at times
+   determined by algorithm hidden in it.
+
+   qdisc's are divided to two categories:
+   - "queues", which have no internal structure visible from outside.
+   - "schedulers", which split all the packets to "traffic classes",
+     using "packet classifiers" (look at cls_api.c)
+
+   In turn, classes may have child qdiscs (as rule, queues)
+   attached to them etc. etc. etc.
+
+   The goal of the routines in this file is to translate
+   information supplied by user in the form of handles
+   to more intelligible for kernel form, to make some sanity
+   checks and part of work, which is common to all qdiscs
+   and to provide rtnetlink notifications.
+
+   All real intelligent work is done inside qdisc modules.
+
+
+
+   Every discipline has two major routines: enqueue and dequeue.
+
+   ---dequeue
+
+   dequeue usually returns a skb to send. It is allowed to return NULL,
+   but it does not mean that queue is empty, it just means that
+   discipline does not want to send anything this time.
+   Queue is really empty if q->q.qlen == 0.
+   For complicated disciplines with multiple queues q->q is not
+   real packet queue, but however q->q.qlen must be valid.
+
+   ---enqueue
+
+   enqueue returns 0, if packet was enqueued successfully.
+   If packet (this one or another one) was dropped, it returns
+   not zero error code.
+   NET_XMIT_DROP 	- this packet dropped
+     Expected action: do not backoff, but wait until queue will clear.
+   NET_XMIT_CN	 	- probably this packet enqueued, but another one dropped.
+     Expected action: backoff or ignore
+
+   Auxiliary routines:
+
+   ---peek
+
+   like dequeue but without removing a packet from the queue
+
+   ---reset
+
+   returns qdisc to initial state: purge all buffers, clear all
+   timers, counters (except for statistics) etc.
+
+   ---init
+
+   initializes newly created qdisc.
+
+   ---destroy
+
+   destroys resources allocated by init and during lifetime of qdisc.
+
+   ---change
+
+   changes qdisc parameters.
+ */
+
+/* Protects list of registered TC modules. It is pure SMP lock. */
+static DEFINE_RWLOCK(qdisc_mod_lock);
+
+
+/************************************************
+ *	Queueing disciplines manipulation.	*
+ ************************************************/
+
+
+/* The list of all installed queueing disciplines. */
+
+static struct Qdisc_ops *qdisc_base;
+
+/* Register/unregister queueing discipline */
+
+int register_qdisc(struct Qdisc_ops *qops)
+{
+	struct Qdisc_ops *q, **qp;
+	int rc = -EEXIST;
+
+	write_lock(&qdisc_mod_lock);
+	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
+		if (!strcmp(qops->id, q->id))
+			goto out;
+
+	if (qops->enqueue == NULL)
+		qops->enqueue = noop_qdisc_ops.enqueue;
+	if (qops->peek == NULL) {
+		if (qops->dequeue == NULL)
+			qops->peek = noop_qdisc_ops.peek;
+		else
+			goto out_einval;
+	}
+	if (qops->dequeue == NULL)
+		qops->dequeue = noop_qdisc_ops.dequeue;
+
+	if (qops->cl_ops) {
+		const struct Qdisc_class_ops *cops = qops->cl_ops;
+
+		if (!(cops->find && cops->walk && cops->leaf))
+			goto out_einval;
+
+		if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
+			goto out_einval;
+	}
+
+	qops->next = NULL;
+	*qp = qops;
+	rc = 0;
+out:
+	write_unlock(&qdisc_mod_lock);
+	return rc;
+
+out_einval:
+	rc = -EINVAL;
+	goto out;
+}
+EXPORT_SYMBOL(register_qdisc);
+
+void unregister_qdisc(struct Qdisc_ops *qops)
+{
+	struct Qdisc_ops *q, **qp;
+	int err = -ENOENT;
+
+	write_lock(&qdisc_mod_lock);
+	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
+		if (q == qops)
+			break;
+	if (q) {
+		*qp = q->next;
+		q->next = NULL;
+		err = 0;
+	}
+	write_unlock(&qdisc_mod_lock);
+
+	WARN(err, "unregister qdisc(%s) failed\n", qops->id);
+}
+EXPORT_SYMBOL(unregister_qdisc);
+
+/* Get default qdisc if not otherwise specified */
+void qdisc_get_default(char *name, size_t len)
+{
+	read_lock(&qdisc_mod_lock);
+	strscpy(name, default_qdisc_ops->id, len);
+	read_unlock(&qdisc_mod_lock);
+}
+
+static struct Qdisc_ops *qdisc_lookup_default(const char *name)
+{
+	struct Qdisc_ops *q = NULL;
+
+	for (q = qdisc_base; q; q = q->next) {
+		if (!strcmp(name, q->id)) {
+			if (!try_module_get(q->owner))
+				q = NULL;
+			break;
+		}
+	}
+
+	return q;
+}
+
+/* Set new default qdisc to use */
+int qdisc_set_default(const char *name)
+{
+	const struct Qdisc_ops *ops;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	write_lock(&qdisc_mod_lock);
+	ops = qdisc_lookup_default(name);
+	if (!ops) {
+		/* Not found, drop lock and try to load module */
+		write_unlock(&qdisc_mod_lock);
+		request_module("sch_%s", name);
+		write_lock(&qdisc_mod_lock);
+
+		ops = qdisc_lookup_default(name);
+	}
+
+	if (ops) {
+		/* Set new default */
+		module_put(default_qdisc_ops->owner);
+		default_qdisc_ops = ops;
+	}
+	write_unlock(&qdisc_mod_lock);
+
+	return ops ? 0 : -ENOENT;
+}
+
+#ifdef CONFIG_NET_SCH_DEFAULT
+/* Set default value from kernel config */
+static int __init sch_default_qdisc(void)
+{
+	return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
+}
+late_initcall(sch_default_qdisc);
+#endif
+
+/* We know handle. Find qdisc among all qdisc's attached to device
+ * (root qdisc, all its children, children of children etc.)
+ * Note: caller either uses rtnl or rcu_read_lock()
+ */
+
+static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
+{
+	struct Qdisc *q;
+
+	if (!qdisc_dev(root))
+		return (root->handle == handle ? root : NULL);
+
+	if (!(root->flags & TCQ_F_BUILTIN) &&
+	    root->handle == handle)
+		return root;
+
+	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle,
+				   lockdep_rtnl_is_held()) {
+		if (q->handle == handle)
+			return q;
+	}
+	return NULL;
+}
+
+void qdisc_hash_add(struct Qdisc *q, bool invisible)
+{
+	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+		ASSERT_RTNL();
+		hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
+		if (invisible)
+			q->flags |= TCQ_F_INVISIBLE;
+	}
+}
+EXPORT_SYMBOL(qdisc_hash_add);
+
+void qdisc_hash_del(struct Qdisc *q)
+{
+	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+		ASSERT_RTNL();
+		hash_del_rcu(&q->hash);
+	}
+}
+EXPORT_SYMBOL(qdisc_hash_del);
+
+struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
+{
+	struct Qdisc *q;
+
+	if (!handle)
+		return NULL;
+	q = qdisc_match_from_root(rtnl_dereference(dev->qdisc), handle);
+	if (q)
+		goto out;
+
+	if (dev_ingress_queue(dev))
+		q = qdisc_match_from_root(
+			rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping),
+			handle);
+out:
+	return q;
+}
+
+struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle)
+{
+	struct netdev_queue *nq;
+	struct Qdisc *q;
+
+	if (!handle)
+		return NULL;
+	q = qdisc_match_from_root(rcu_dereference(dev->qdisc), handle);
+	if (q)
+		goto out;
+
+	nq = dev_ingress_queue_rcu(dev);
+	if (nq)
+		q = qdisc_match_from_root(rcu_dereference(nq->qdisc_sleeping),
+					  handle);
+out:
+	return q;
+}
+
+static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
+{
+	unsigned long cl;
+	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
+
+	if (cops == NULL)
+		return NULL;
+	cl = cops->find(p, classid);
+
+	if (cl == 0)
+		return NULL;
+	return cops->leaf(p, cl);
+}
+
+/* Find queueing discipline by name */
+
+static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
+{
+	struct Qdisc_ops *q = NULL;
+
+	if (kind) {
+		read_lock(&qdisc_mod_lock);
+		for (q = qdisc_base; q; q = q->next) {
+			if (nla_strcmp(kind, q->id) == 0) {
+				if (!try_module_get(q->owner))
+					q = NULL;
+				break;
+			}
+		}
+		read_unlock(&qdisc_mod_lock);
+	}
+	return q;
+}
+
+/* The linklayer setting were not transferred from iproute2, in older
+ * versions, and the rate tables lookup systems have been dropped in
+ * the kernel. To keep backward compatible with older iproute2 tc
+ * utils, we detect the linklayer setting by detecting if the rate
+ * table were modified.
+ *
+ * For linklayer ATM table entries, the rate table will be aligned to
+ * 48 bytes, thus some table entries will contain the same value.  The
+ * mpu (min packet unit) is also encoded into the old rate table, thus
+ * starting from the mpu, we find low and high table entries for
+ * mapping this cell.  If these entries contain the same value, when
+ * the rate tables have been modified for linklayer ATM.
+ *
+ * This is done by rounding mpu to the nearest 48 bytes cell/entry,
+ * and then roundup to the next cell, calc the table entry one below,
+ * and compare.
+ */
+static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
+{
+	int low       = roundup(r->mpu, 48);
+	int high      = roundup(low+1, 48);
+	int cell_low  = low >> r->cell_log;
+	int cell_high = (high >> r->cell_log) - 1;
+
+	/* rtab is too inaccurate at rates > 100Mbit/s */
+	if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
+		pr_debug("TC linklayer: Giving up ATM detection\n");
+		return TC_LINKLAYER_ETHERNET;
+	}
+
+	if ((cell_high > cell_low) && (cell_high < 256)
+	    && (rtab[cell_low] == rtab[cell_high])) {
+		pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
+			 cell_low, cell_high, rtab[cell_high]);
+		return TC_LINKLAYER_ATM;
+	}
+	return TC_LINKLAYER_ETHERNET;
+}
+
+static struct qdisc_rate_table *qdisc_rtab_list;
+
+struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
+					struct nlattr *tab,
+					struct netlink_ext_ack *extack)
+{
+	struct qdisc_rate_table *rtab;
+
+	if (tab == NULL || r->rate == 0 ||
+	    r->cell_log == 0 || r->cell_log >= 32 ||
+	    nla_len(tab) != TC_RTAB_SIZE) {
+		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
+		return NULL;
+	}
+
+	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
+		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
+		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
+			rtab->refcnt++;
+			return rtab;
+		}
+	}
+
+	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
+	if (rtab) {
+		rtab->rate = *r;
+		rtab->refcnt = 1;
+		memcpy(rtab->data, nla_data(tab), 1024);
+		if (r->linklayer == TC_LINKLAYER_UNAWARE)
+			r->linklayer = __detect_linklayer(r, rtab->data);
+		rtab->next = qdisc_rtab_list;
+		qdisc_rtab_list = rtab;
+	} else {
+		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
+	}
+	return rtab;
+}
+EXPORT_SYMBOL(qdisc_get_rtab);
+
+void qdisc_put_rtab(struct qdisc_rate_table *tab)
+{
+	struct qdisc_rate_table *rtab, **rtabp;
+
+	if (!tab || --tab->refcnt)
+		return;
+
+	for (rtabp = &qdisc_rtab_list;
+	     (rtab = *rtabp) != NULL;
+	     rtabp = &rtab->next) {
+		if (rtab == tab) {
+			*rtabp = rtab->next;
+			kfree(rtab);
+			return;
+		}
+	}
+}
+EXPORT_SYMBOL(qdisc_put_rtab);
+
+static LIST_HEAD(qdisc_stab_list);
+
+static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
+	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
+	[TCA_STAB_DATA] = { .type = NLA_BINARY },
+};
+
+static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
+					       struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[TCA_STAB_MAX + 1];
+	struct qdisc_size_table *stab;
+	struct tc_sizespec *s;
+	unsigned int tsize = 0;
+	u16 *tab = NULL;
+	int err;
+
+	err = nla_parse_nested_deprecated(tb, TCA_STAB_MAX, opt, stab_policy,
+					  extack);
+	if (err < 0)
+		return ERR_PTR(err);
+	if (!tb[TCA_STAB_BASE]) {
+		NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
+		return ERR_PTR(-EINVAL);
+	}
+
+	s = nla_data(tb[TCA_STAB_BASE]);
+
+	if (s->tsize > 0) {
+		if (!tb[TCA_STAB_DATA]) {
+			NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
+			return ERR_PTR(-EINVAL);
+		}
+		tab = nla_data(tb[TCA_STAB_DATA]);
+		tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
+	}
+
+	if (tsize != s->tsize || (!tab && tsize > 0)) {
+		NL_SET_ERR_MSG(extack, "Invalid size of size table");
+		return ERR_PTR(-EINVAL);
+	}
+
+	list_for_each_entry(stab, &qdisc_stab_list, list) {
+		if (memcmp(&stab->szopts, s, sizeof(*s)))
+			continue;
+		if (tsize > 0 &&
+		    memcmp(stab->data, tab, flex_array_size(stab, data, tsize)))
+			continue;
+		stab->refcnt++;
+		return stab;
+	}
+
+	if (s->size_log > STAB_SIZE_LOG_MAX ||
+	    s->cell_log > STAB_SIZE_LOG_MAX) {
+		NL_SET_ERR_MSG(extack, "Invalid logarithmic size of size table");
+		return ERR_PTR(-EINVAL);
+	}
+
+	stab = kmalloc(struct_size(stab, data, tsize), GFP_KERNEL);
+	if (!stab)
+		return ERR_PTR(-ENOMEM);
+
+	stab->refcnt = 1;
+	stab->szopts = *s;
+	if (tsize > 0)
+		memcpy(stab->data, tab, flex_array_size(stab, data, tsize));
+
+	list_add_tail(&stab->list, &qdisc_stab_list);
+
+	return stab;
+}
+
+void qdisc_put_stab(struct qdisc_size_table *tab)
+{
+	if (!tab)
+		return;
+
+	if (--tab->refcnt == 0) {
+		list_del(&tab->list);
+		kfree_rcu(tab, rcu);
+	}
+}
+EXPORT_SYMBOL(qdisc_put_stab);
+
+static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
+{
+	struct nlattr *nest;
+
+	nest = nla_nest_start_noflag(skb, TCA_STAB);
+	if (nest == NULL)
+		goto nla_put_failure;
+	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
+		goto nla_put_failure;
+	nla_nest_end(skb, nest);
+
+	return skb->len;
+
+nla_put_failure:
+	return -1;
+}
+
+void __qdisc_calculate_pkt_len(struct sk_buff *skb,
+			       const struct qdisc_size_table *stab)
+{
+	int pkt_len, slot;
+
+	pkt_len = skb->len + stab->szopts.overhead;
+	if (unlikely(!stab->szopts.tsize))
+		goto out;
+
+	slot = pkt_len + stab->szopts.cell_align;
+	if (unlikely(slot < 0))
+		slot = 0;
+
+	slot >>= stab->szopts.cell_log;
+	if (likely(slot < stab->szopts.tsize))
+		pkt_len = stab->data[slot];
+	else
+		pkt_len = stab->data[stab->szopts.tsize - 1] *
+				(slot / stab->szopts.tsize) +
+				stab->data[slot % stab->szopts.tsize];
+
+	pkt_len <<= stab->szopts.size_log;
+out:
+	if (unlikely(pkt_len < 1))
+		pkt_len = 1;
+	qdisc_skb_cb(skb)->pkt_len = pkt_len;
+}
+EXPORT_SYMBOL(__qdisc_calculate_pkt_len);
+
+void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
+{
+	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
+		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
+			txt, qdisc->ops->id, qdisc->handle >> 16);
+		qdisc->flags |= TCQ_F_WARN_NONWC;
+	}
+}
+EXPORT_SYMBOL(qdisc_warn_nonwc);
+
+static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
+{
+	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
+						 timer);
+
+	rcu_read_lock();
+	__netif_schedule(qdisc_root(wd->qdisc));
+	rcu_read_unlock();
+
+	return HRTIMER_NORESTART;
+}
+
+void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
+				 clockid_t clockid)
+{
+	hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
+	wd->timer.function = qdisc_watchdog;
+	wd->qdisc = qdisc;
+}
+EXPORT_SYMBOL(qdisc_watchdog_init_clockid);
+
+void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
+{
+	qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
+}
+EXPORT_SYMBOL(qdisc_watchdog_init);
+
+void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
+				      u64 delta_ns)
+{
+	bool deactivated;
+
+	rcu_read_lock();
+	deactivated = test_bit(__QDISC_STATE_DEACTIVATED,
+			       &qdisc_root_sleeping(wd->qdisc)->state);
+	rcu_read_unlock();
+	if (deactivated)
+		return;
+
+	if (hrtimer_is_queued(&wd->timer)) {
+		/* If timer is already set in [expires, expires + delta_ns],
+		 * do not reprogram it.
+		 */
+		if (wd->last_expires - expires <= delta_ns)
+			return;
+	}
+
+	wd->last_expires = expires;
+	hrtimer_start_range_ns(&wd->timer,
+			       ns_to_ktime(expires),
+			       delta_ns,
+			       HRTIMER_MODE_ABS_PINNED);
+}
+EXPORT_SYMBOL(qdisc_watchdog_schedule_range_ns);
+
+void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
+{
+	hrtimer_cancel(&wd->timer);
+}
+EXPORT_SYMBOL(qdisc_watchdog_cancel);
+
+static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
+{
+	struct hlist_head *h;
+	unsigned int i;
+
+	h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);
+
+	if (h != NULL) {
+		for (i = 0; i < n; i++)
+			INIT_HLIST_HEAD(&h[i]);
+	}
+	return h;
+}
+
+void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
+{
+	struct Qdisc_class_common *cl;
+	struct hlist_node *next;
+	struct hlist_head *nhash, *ohash;
+	unsigned int nsize, nmask, osize;
+	unsigned int i, h;
+
+	/* Rehash when load factor exceeds 0.75 */
+	if (clhash->hashelems * 4 <= clhash->hashsize * 3)
+		return;
+	nsize = clhash->hashsize * 2;
+	nmask = nsize - 1;
+	nhash = qdisc_class_hash_alloc(nsize);
+	if (nhash == NULL)
+		return;
+
+	ohash = clhash->hash;
+	osize = clhash->hashsize;
+
+	sch_tree_lock(sch);
+	for (i = 0; i < osize; i++) {
+		hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
+			h = qdisc_class_hash(cl->classid, nmask);
+			hlist_add_head(&cl->hnode, &nhash[h]);
+		}
+	}
+	clhash->hash     = nhash;
+	clhash->hashsize = nsize;
+	clhash->hashmask = nmask;
+	sch_tree_unlock(sch);
+
+	kvfree(ohash);
+}
+EXPORT_SYMBOL(qdisc_class_hash_grow);
+
+int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
+{
+	unsigned int size = 4;
+
+	clhash->hash = qdisc_class_hash_alloc(size);
+	if (!clhash->hash)
+		return -ENOMEM;
+	clhash->hashsize  = size;
+	clhash->hashmask  = size - 1;
+	clhash->hashelems = 0;
+	return 0;
+}
+EXPORT_SYMBOL(qdisc_class_hash_init);
+
+void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
+{
+	kvfree(clhash->hash);
+}
+EXPORT_SYMBOL(qdisc_class_hash_destroy);
+
+void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
+			     struct Qdisc_class_common *cl)
+{
+	unsigned int h;
+
+	INIT_HLIST_NODE(&cl->hnode);
+	h = qdisc_class_hash(cl->classid, clhash->hashmask);
+	hlist_add_head(&cl->hnode, &clhash->hash[h]);
+	clhash->hashelems++;
+}
+EXPORT_SYMBOL(qdisc_class_hash_insert);
+
+void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
+			     struct Qdisc_class_common *cl)
+{
+	hlist_del(&cl->hnode);
+	clhash->hashelems--;
+}
+EXPORT_SYMBOL(qdisc_class_hash_remove);
+
+/* Allocate an unique handle from space managed by kernel
+ * Possible range is [8000-FFFF]:0000 (0x8000 values)
+ */
+static u32 qdisc_alloc_handle(struct net_device *dev)
+{
+	int i = 0x8000;
+	static u32 autohandle = TC_H_MAKE(0x80000000U, 0);
+
+	do {
+		autohandle += TC_H_MAKE(0x10000U, 0);
+		if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
+			autohandle = TC_H_MAKE(0x80000000U, 0);
+		if (!qdisc_lookup(dev, autohandle))
+			return autohandle;
+		cond_resched();
+	} while	(--i > 0);
+
+	return 0;
+}
+
+void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
+{
+	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
+	const struct Qdisc_class_ops *cops;
+	unsigned long cl;
+	u32 parentid;
+	bool notify;
+	int drops;
+
+	if (n == 0 && len == 0)
+		return;
+	drops = max_t(int, n, 0);
+	rcu_read_lock();
+	while ((parentid = sch->parent)) {
+		if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
+			break;
+
+		if (sch->flags & TCQ_F_NOPARENT)
+			break;
+		/* Notify parent qdisc only if child qdisc becomes empty.
+		 *
+		 * If child was empty even before update then backlog
+		 * counter is screwed and we skip notification because
+		 * parent class is already passive.
+		 *
+		 * If the original child was offloaded then it is allowed
+		 * to be seem as empty, so the parent is notified anyway.
+		 */
+		notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
+						       !qdisc_is_offloaded);
+		/* TODO: perform the search on a per txq basis */
+		sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
+		if (sch == NULL) {
+			WARN_ON_ONCE(parentid != TC_H_ROOT);
+			break;
+		}
+		cops = sch->ops->cl_ops;
+		if (notify && cops->qlen_notify) {
+			cl = cops->find(sch, parentid);
+			cops->qlen_notify(sch, cl);
+		}
+		sch->q.qlen -= n;
+		sch->qstats.backlog -= len;
+		__qdisc_qstats_drop(sch, drops);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
+
+int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
+			      void *type_data)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	int err;
+
+	sch->flags &= ~TCQ_F_OFFLOADED;
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+		return 0;
+
+	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
+	if (err == -EOPNOTSUPP)
+		return 0;
+
+	if (!err)
+		sch->flags |= TCQ_F_OFFLOADED;
+
+	return err;
+}
+EXPORT_SYMBOL(qdisc_offload_dump_helper);
+
+void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
+				struct Qdisc *new, struct Qdisc *old,
+				enum tc_setup_type type, void *type_data,
+				struct netlink_ext_ack *extack)
+{
+	bool any_qdisc_is_offloaded;
+	int err;
+
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
+		return;
+
+	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
+
+	/* Don't report error if the graft is part of destroy operation. */
+	if (!err || !new || new == &noop_qdisc)
+		return;
+
+	/* Don't report error if the parent, the old child and the new
+	 * one are not offloaded.
+	 */
+	any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
+	any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
+	any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;
+
+	if (any_qdisc_is_offloaded)
+		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
+}
+EXPORT_SYMBOL(qdisc_offload_graft_helper);
+
+void qdisc_offload_query_caps(struct net_device *dev,
+			      enum tc_setup_type type,
+			      void *caps, size_t caps_len)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct tc_query_caps_base base = {
+		.type = type,
+		.caps = caps,
+	};
+
+	memset(caps, 0, caps_len);
+
+	if (ops->ndo_setup_tc)
+		ops->ndo_setup_tc(dev, TC_QUERY_CAPS, &base);
+}
+EXPORT_SYMBOL(qdisc_offload_query_caps);
+
+static void qdisc_offload_graft_root(struct net_device *dev,
+				     struct Qdisc *new, struct Qdisc *old,
+				     struct netlink_ext_ack *extack)
+{
+	struct tc_root_qopt_offload graft_offload = {
+		.command	= TC_ROOT_GRAFT,
+		.handle		= new ? new->handle : 0,
+		.ingress	= (new && new->flags & TCQ_F_INGRESS) ||
+				  (old && old->flags & TCQ_F_INGRESS),
+	};
+
+	qdisc_offload_graft_helper(dev, NULL, new, old,
+				   TC_SETUP_ROOT_QDISC, &graft_offload, extack);
+}
+
+static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
+			 u32 portid, u32 seq, u16 flags, int event,
+			 struct netlink_ext_ack *extack)
+{
+	struct gnet_stats_basic_sync __percpu *cpu_bstats = NULL;
+	struct gnet_stats_queue __percpu *cpu_qstats = NULL;
+	struct tcmsg *tcm;
+	struct nlmsghdr  *nlh;
+	unsigned char *b = skb_tail_pointer(skb);
+	struct gnet_dump d;
+	struct qdisc_size_table *stab;
+	u32 block_index;
+	__u32 qlen;
+
+	cond_resched();
+	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
+	if (!nlh)
+		goto out_nlmsg_trim;
+	tcm = nlmsg_data(nlh);
+	tcm->tcm_family = AF_UNSPEC;
+	tcm->tcm__pad1 = 0;
+	tcm->tcm__pad2 = 0;
+	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
+	tcm->tcm_parent = clid;
+	tcm->tcm_handle = q->handle;
+	tcm->tcm_info = refcount_read(&q->refcnt);
+	if (nla_put_string(skb, TCA_KIND, q->ops->id))
+		goto nla_put_failure;
+	if (q->ops->ingress_block_get) {
+		block_index = q->ops->ingress_block_get(q);
+		if (block_index &&
+		    nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
+			goto nla_put_failure;
+	}
+	if (q->ops->egress_block_get) {
+		block_index = q->ops->egress_block_get(q);
+		if (block_index &&
+		    nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
+			goto nla_put_failure;
+	}
+	if (q->ops->dump && q->ops->dump(q, skb) < 0)
+		goto nla_put_failure;
+	if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
+		goto nla_put_failure;
+	qlen = qdisc_qlen_sum(q);
+
+	stab = rtnl_dereference(q->stab);
+	if (stab && qdisc_dump_stab(skb, stab) < 0)
+		goto nla_put_failure;
+
+	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
+					 NULL, &d, TCA_PAD) < 0)
+		goto nla_put_failure;
+
+	if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
+		goto nla_put_failure;
+
+	if (qdisc_is_percpu_stats(q)) {
+		cpu_bstats = q->cpu_bstats;
+		cpu_qstats = q->cpu_qstats;
+	}
+
+	if (gnet_stats_copy_basic(&d, cpu_bstats, &q->bstats, true) < 0 ||
+	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
+	    gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
+		goto nla_put_failure;
+
+	if (gnet_stats_finish_copy(&d) < 0)
+		goto nla_put_failure;
+
+	if (extack && extack->_msg &&
+	    nla_put_string(skb, TCA_EXT_WARN_MSG, extack->_msg))
+		goto out_nlmsg_trim;
+
+	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
+
+	return skb->len;
+
+out_nlmsg_trim:
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
+{
+	if (q->flags & TCQ_F_BUILTIN)
+		return true;
+	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
+		return true;
+
+	return false;
+}
+
+static int qdisc_notify(struct net *net, struct sk_buff *oskb,
+			struct nlmsghdr *n, u32 clid,
+			struct Qdisc *old, struct Qdisc *new,
+			struct netlink_ext_ack *extack)
+{
+	struct sk_buff *skb;
+	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+
+	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	if (old && !tc_qdisc_dump_ignore(old, false)) {
+		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
+				  0, RTM_DELQDISC, extack) < 0)
+			goto err_out;
+	}
+	if (new && !tc_qdisc_dump_ignore(new, false)) {
+		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
+				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC, extack) < 0)
+			goto err_out;
+	}
+
+	if (skb->len)
+		return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
+				      n->nlmsg_flags & NLM_F_ECHO);
+
+err_out:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static void notify_and_destroy(struct net *net, struct sk_buff *skb,
+			       struct nlmsghdr *n, u32 clid,
+			       struct Qdisc *old, struct Qdisc *new,
+			       struct netlink_ext_ack *extack)
+{
+	if (new || old)
+		qdisc_notify(net, skb, n, clid, old, new, extack);
+
+	if (old)
+		qdisc_put(old);
+}
+
+static void qdisc_clear_nolock(struct Qdisc *sch)
+{
+	sch->flags &= ~TCQ_F_NOLOCK;
+	if (!(sch->flags & TCQ_F_CPUSTATS))
+		return;
+
+	free_percpu(sch->cpu_bstats);
+	free_percpu(sch->cpu_qstats);
+	sch->cpu_bstats = NULL;
+	sch->cpu_qstats = NULL;
+	sch->flags &= ~TCQ_F_CPUSTATS;
+}
+
+/* Graft qdisc "new" to class "classid" of qdisc "parent" or
+ * to device "dev".
+ *
+ * When appropriate send a netlink notification using 'skb'
+ * and "n".
+ *
+ * On success, destroy old qdisc.
+ */
+
+static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
+		       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
+		       struct Qdisc *new, struct Qdisc *old,
+		       struct netlink_ext_ack *extack)
+{
+	struct Qdisc *q = old;
+	struct net *net = dev_net(dev);
+
+	if (parent == NULL) {
+		unsigned int i, num_q, ingress;
+		struct netdev_queue *dev_queue;
+
+		ingress = 0;
+		num_q = dev->num_tx_queues;
+		if ((q && q->flags & TCQ_F_INGRESS) ||
+		    (new && new->flags & TCQ_F_INGRESS)) {
+			ingress = 1;
+			dev_queue = dev_ingress_queue(dev);
+			if (!dev_queue) {
+				NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
+				return -ENOENT;
+			}
+
+			q = rtnl_dereference(dev_queue->qdisc_sleeping);
+
+			/* This is the counterpart of that qdisc_refcount_inc_nz() call in
+			 * __tcf_qdisc_find() for filter requests.
+			 */
+			if (!qdisc_refcount_dec_if_one(q)) {
+				NL_SET_ERR_MSG(extack,
+					       "Current ingress or clsact Qdisc has ongoing filter requests");
+				return -EBUSY;
+			}
+		}
+
+		if (dev->flags & IFF_UP)
+			dev_deactivate(dev);
+
+		qdisc_offload_graft_root(dev, new, old, extack);
+
+		if (new && new->ops->attach && !ingress)
+			goto skip;
+
+		if (!ingress) {
+			for (i = 0; i < num_q; i++) {
+				dev_queue = netdev_get_tx_queue(dev, i);
+				old = dev_graft_qdisc(dev_queue, new);
+
+				if (new && i > 0)
+					qdisc_refcount_inc(new);
+				qdisc_put(old);
+			}
+		} else {
+			old = dev_graft_qdisc(dev_queue, NULL);
+
+			/* {ingress,clsact}_destroy() @old before grafting @new to avoid
+			 * unprotected concurrent accesses to net_device::miniq_{in,e}gress
+			 * pointer(s) in mini_qdisc_pair_swap().
+			 */
+			qdisc_notify(net, skb, n, classid, old, new, extack);
+			qdisc_destroy(old);
+
+			dev_graft_qdisc(dev_queue, new);
+		}
+
+skip:
+		if (!ingress) {
+			old = rtnl_dereference(dev->qdisc);
+			if (new && !new->ops->attach)
+				qdisc_refcount_inc(new);
+			rcu_assign_pointer(dev->qdisc, new ? : &noop_qdisc);
+
+			notify_and_destroy(net, skb, n, classid, old, new, extack);
+
+			if (new && new->ops->attach)
+				new->ops->attach(new);
+		}
+
+		if (dev->flags & IFF_UP)
+			dev_activate(dev);
+	} else {
+		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
+		unsigned long cl;
+		int err;
+
+		/* Only support running class lockless if parent is lockless */
+		if (new && (new->flags & TCQ_F_NOLOCK) && !(parent->flags & TCQ_F_NOLOCK))
+			qdisc_clear_nolock(new);
+
+		if (!cops || !cops->graft)
+			return -EOPNOTSUPP;
+
+		cl = cops->find(parent, classid);
+		if (!cl) {
+			NL_SET_ERR_MSG(extack, "Specified class not found");
+			return -ENOENT;
+		}
+
+		if (new && new->ops == &noqueue_qdisc_ops) {
+			NL_SET_ERR_MSG(extack, "Cannot assign noqueue to a class");
+			return -EINVAL;
+		}
+
+		err = cops->graft(parent, cl, new, &old, extack);
+		if (err)
+			return err;
+		notify_and_destroy(net, skb, n, classid, old, new, extack);
+	}
+	return 0;
+}
+
+static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
+				   struct netlink_ext_ack *extack)
+{
+	u32 block_index;
+
+	if (tca[TCA_INGRESS_BLOCK]) {
+		block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);
+
+		if (!block_index) {
+			NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
+			return -EINVAL;
+		}
+		if (!sch->ops->ingress_block_set) {
+			NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
+			return -EOPNOTSUPP;
+		}
+		sch->ops->ingress_block_set(sch, block_index);
+	}
+	if (tca[TCA_EGRESS_BLOCK]) {
+		block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);
+
+		if (!block_index) {
+			NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
+			return -EINVAL;
+		}
+		if (!sch->ops->egress_block_set) {
+			NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
+			return -EOPNOTSUPP;
+		}
+		sch->ops->egress_block_set(sch, block_index);
+	}
+	return 0;
+}
+
+/*
+   Allocate and initialize new qdisc.
+
+   Parameters are passed via opt.
+ */
+
+static struct Qdisc *qdisc_create(struct net_device *dev,
+				  struct netdev_queue *dev_queue,
+				  u32 parent, u32 handle,
+				  struct nlattr **tca, int *errp,
+				  struct netlink_ext_ack *extack)
+{
+	int err;
+	struct nlattr *kind = tca[TCA_KIND];
+	struct Qdisc *sch;
+	struct Qdisc_ops *ops;
+	struct qdisc_size_table *stab;
+
+	ops = qdisc_lookup_ops(kind);
+#ifdef CONFIG_MODULES
+	if (ops == NULL && kind != NULL) {
+		char name[IFNAMSIZ];
+		if (nla_strscpy(name, kind, IFNAMSIZ) >= 0) {
+			/* We dropped the RTNL semaphore in order to
+			 * perform the module load.  So, even if we
+			 * succeeded in loading the module we have to
+			 * tell the caller to replay the request.  We
+			 * indicate this using -EAGAIN.
+			 * We replay the request because the device may
+			 * go away in the mean time.
+			 */
+			rtnl_unlock();
+			request_module("sch_%s", name);
+			rtnl_lock();
+			ops = qdisc_lookup_ops(kind);
+			if (ops != NULL) {
+				/* We will try again qdisc_lookup_ops,
+				 * so don't keep a reference.
+				 */
+				module_put(ops->owner);
+				err = -EAGAIN;
+				goto err_out;
+			}
+		}
+	}
+#endif
+
+	err = -ENOENT;
+	if (!ops) {
+		NL_SET_ERR_MSG(extack, "Specified qdisc kind is unknown");
+		goto err_out;
+	}
+
+	sch = qdisc_alloc(dev_queue, ops, extack);
+	if (IS_ERR(sch)) {
+		err = PTR_ERR(sch);
+		goto err_out2;
+	}
+
+	sch->parent = parent;
+
+	if (handle == TC_H_INGRESS) {
+		if (!(sch->flags & TCQ_F_INGRESS)) {
+			NL_SET_ERR_MSG(extack,
+				       "Specified parent ID is reserved for ingress and clsact Qdiscs");
+			err = -EINVAL;
+			goto err_out3;
+		}
+		handle = TC_H_MAKE(TC_H_INGRESS, 0);
+	} else {
+		if (handle == 0) {
+			handle = qdisc_alloc_handle(dev);
+			if (handle == 0) {
+				NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
+				err = -ENOSPC;
+				goto err_out3;
+			}
+		}
+		if (!netif_is_multiqueue(dev))
+			sch->flags |= TCQ_F_ONETXQUEUE;
+	}
+
+	sch->handle = handle;
+
+	/* This exist to keep backward compatible with a userspace
+	 * loophole, what allowed userspace to get IFF_NO_QUEUE
+	 * facility on older kernels by setting tx_queue_len=0 (prior
+	 * to qdisc init), and then forgot to reinit tx_queue_len
+	 * before again attaching a qdisc.
+	 */
+	if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
+		dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
+		netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
+	}
+
+	err = qdisc_block_indexes_set(sch, tca, extack);
+	if (err)
+		goto err_out3;
+
+	if (ops->init) {
+		err = ops->init(sch, tca[TCA_OPTIONS], extack);
+		if (err != 0)
+			goto err_out5;
+	}
+
+	if (tca[TCA_STAB]) {
+		stab = qdisc_get_stab(tca[TCA_STAB], extack);
+		if (IS_ERR(stab)) {
+			err = PTR_ERR(stab);
+			goto err_out4;
+		}
+		rcu_assign_pointer(sch->stab, stab);
+	}
+	if (tca[TCA_RATE]) {
+		err = -EOPNOTSUPP;
+		if (sch->flags & TCQ_F_MQROOT) {
+			NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
+			goto err_out4;
+		}
+
+		err = gen_new_estimator(&sch->bstats,
+					sch->cpu_bstats,
+					&sch->rate_est,
+					NULL,
+					true,
+					tca[TCA_RATE]);
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
+			goto err_out4;
+		}
+	}
+
+	qdisc_hash_add(sch, false);
+	trace_qdisc_create(ops, dev, parent);
+
+	return sch;
+
+err_out5:
+	/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
+	if (ops->destroy)
+		ops->destroy(sch);
+err_out3:
+	netdev_put(dev, &sch->dev_tracker);
+	qdisc_free(sch);
+err_out2:
+	module_put(ops->owner);
+err_out:
+	*errp = err;
+	return NULL;
+
+err_out4:
+	/*
+	 * Any broken qdiscs that would require a ops->reset() here?
+	 * The qdisc was never in action so it shouldn't be necessary.
+	 */
+	qdisc_put_stab(rtnl_dereference(sch->stab));
+	if (ops->destroy)
+		ops->destroy(sch);
+	goto err_out3;
+}
+
+static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
+			struct netlink_ext_ack *extack)
+{
+	struct qdisc_size_table *ostab, *stab = NULL;
+	int err = 0;
+
+	if (tca[TCA_OPTIONS]) {
+		if (!sch->ops->change) {
+			NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
+			return -EINVAL;
+		}
+		if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
+			NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
+			return -EOPNOTSUPP;
+		}
+		err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
+		if (err)
+			return err;
+	}
+
+	if (tca[TCA_STAB]) {
+		stab = qdisc_get_stab(tca[TCA_STAB], extack);
+		if (IS_ERR(stab))
+			return PTR_ERR(stab);
+	}
+
+	ostab = rtnl_dereference(sch->stab);
+	rcu_assign_pointer(sch->stab, stab);
+	qdisc_put_stab(ostab);
+
+	if (tca[TCA_RATE]) {
+		/* NB: ignores errors from replace_estimator
+		   because change can't be undone. */
+		if (sch->flags & TCQ_F_MQROOT)
+			goto out;
+		gen_replace_estimator(&sch->bstats,
+				      sch->cpu_bstats,
+				      &sch->rate_est,
+				      NULL,
+				      true,
+				      tca[TCA_RATE]);
+	}
+out:
+	return 0;
+}
+
+struct check_loop_arg {
+	struct qdisc_walker	w;
+	struct Qdisc		*p;
+	int			depth;
+};
+
+static int check_loop_fn(struct Qdisc *q, unsigned long cl,
+			 struct qdisc_walker *w);
+
+static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
+{
+	struct check_loop_arg	arg;
+
+	if (q->ops->cl_ops == NULL)
+		return 0;
+
+	arg.w.stop = arg.w.skip = arg.w.count = 0;
+	arg.w.fn = check_loop_fn;
+	arg.depth = depth;
+	arg.p = p;
+	q->ops->cl_ops->walk(q, &arg.w);
+	return arg.w.stop ? -ELOOP : 0;
+}
+
+static int
+check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
+{
+	struct Qdisc *leaf;
+	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
+	struct check_loop_arg *arg = (struct check_loop_arg *)w;
+
+	leaf = cops->leaf(q, cl);
+	if (leaf) {
+		if (leaf == arg->p || arg->depth > 7)
+			return -ELOOP;
+		return check_loop(leaf, arg->p, arg->depth + 1);
+	}
+	return 0;
+}
+
+const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
+	[TCA_KIND]		= { .type = NLA_STRING },
+	[TCA_RATE]		= { .type = NLA_BINARY,
+				    .len = sizeof(struct tc_estimator) },
+	[TCA_STAB]		= { .type = NLA_NESTED },
+	[TCA_DUMP_INVISIBLE]	= { .type = NLA_FLAG },
+	[TCA_CHAIN]		= { .type = NLA_U32 },
+	[TCA_INGRESS_BLOCK]	= { .type = NLA_U32 },
+	[TCA_EGRESS_BLOCK]	= { .type = NLA_U32 },
+};
+
+/*
+ * Delete/get qdisc.
+ */
+
+static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
+			struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tcmsg *tcm = nlmsg_data(n);
+	struct nlattr *tca[TCA_MAX + 1];
+	struct net_device *dev;
+	u32 clid;
+	struct Qdisc *q = NULL;
+	struct Qdisc *p = NULL;
+	int err;
+
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
+				     rtm_tca_policy, extack);
+	if (err < 0)
+		return err;
+
+	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+	if (!dev)
+		return -ENODEV;
+
+	clid = tcm->tcm_parent;
+	if (clid) {
+		if (clid != TC_H_ROOT) {
+			if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
+				p = qdisc_lookup(dev, TC_H_MAJ(clid));
+				if (!p) {
+					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
+					return -ENOENT;
+				}
+				q = qdisc_leaf(p, clid);
+			} else if (dev_ingress_queue(dev)) {
+				q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
+			}
+		} else {
+			q = rtnl_dereference(dev->qdisc);
+		}
+		if (!q) {
+			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
+			return -ENOENT;
+		}
+
+		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
+			NL_SET_ERR_MSG(extack, "Invalid handle");
+			return -EINVAL;
+		}
+	} else {
+		q = qdisc_lookup(dev, tcm->tcm_handle);
+		if (!q) {
+			NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
+			return -ENOENT;
+		}
+	}
+
+	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
+		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
+		return -EINVAL;
+	}
+
+	if (n->nlmsg_type == RTM_DELQDISC) {
+		if (!clid) {
+			NL_SET_ERR_MSG(extack, "Classid cannot be zero");
+			return -EINVAL;
+		}
+		if (q->handle == 0) {
+			NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
+			return -ENOENT;
+		}
+		err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
+		if (err != 0)
+			return err;
+	} else {
+		qdisc_notify(net, skb, n, clid, NULL, q, NULL);
+	}
+	return 0;
+}
+
+static bool req_create_or_replace(struct nlmsghdr *n)
+{
+	return (n->nlmsg_flags & NLM_F_CREATE &&
+		n->nlmsg_flags & NLM_F_REPLACE);
+}
+
+static bool req_create_exclusive(struct nlmsghdr *n)
+{
+	return (n->nlmsg_flags & NLM_F_CREATE &&
+		n->nlmsg_flags & NLM_F_EXCL);
+}
+
+static bool req_change(struct nlmsghdr *n)
+{
+	return (!(n->nlmsg_flags & NLM_F_CREATE) &&
+		!(n->nlmsg_flags & NLM_F_REPLACE) &&
+		!(n->nlmsg_flags & NLM_F_EXCL));
+}
+
+/*
+ * Create/change qdisc.
+ */
+static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
+			   struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tcmsg *tcm;
+	struct nlattr *tca[TCA_MAX + 1];
+	struct net_device *dev;
+	u32 clid;
+	struct Qdisc *q, *p;
+	int err;
+
+replay:
+	/* Reinit, just in case something touches this. */
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
+				     rtm_tca_policy, extack);
+	if (err < 0)
+		return err;
+
+	tcm = nlmsg_data(n);
+	clid = tcm->tcm_parent;
+	q = p = NULL;
+
+	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+	if (!dev)
+		return -ENODEV;
+
+
+	if (clid) {
+		if (clid != TC_H_ROOT) {
+			if (clid != TC_H_INGRESS) {
+				p = qdisc_lookup(dev, TC_H_MAJ(clid));
+				if (!p) {
+					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
+					return -ENOENT;
+				}
+				q = qdisc_leaf(p, clid);
+			} else if (dev_ingress_queue_create(dev)) {
+				q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
+			}
+		} else {
+			q = rtnl_dereference(dev->qdisc);
+		}
+
+		/* It may be default qdisc, ignore it */
+		if (q && q->handle == 0)
+			q = NULL;
+
+		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
+			if (tcm->tcm_handle) {
+				if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
+					NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
+					return -EEXIST;
+				}
+				if (TC_H_MIN(tcm->tcm_handle)) {
+					NL_SET_ERR_MSG(extack, "Invalid minor handle");
+					return -EINVAL;
+				}
+				q = qdisc_lookup(dev, tcm->tcm_handle);
+				if (!q)
+					goto create_n_graft;
+				if (n->nlmsg_flags & NLM_F_EXCL) {
+					NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
+					return -EEXIST;
+				}
+				if (tca[TCA_KIND] &&
+				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
+					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
+					return -EINVAL;
+				}
+				if (q->flags & TCQ_F_INGRESS) {
+					NL_SET_ERR_MSG(extack,
+						       "Cannot regraft ingress or clsact Qdiscs");
+					return -EINVAL;
+				}
+				if (q == p ||
+				    (p && check_loop(q, p, 0))) {
+					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
+					return -ELOOP;
+				}
+				if (clid == TC_H_INGRESS) {
+					NL_SET_ERR_MSG(extack, "Ingress cannot graft directly");
+					return -EINVAL;
+				}
+				qdisc_refcount_inc(q);
+				goto graft;
+			} else {
+				if (!q)
+					goto create_n_graft;
+
+				/* This magic test requires explanation.
+				 *
+				 *   We know, that some child q is already
+				 *   attached to this parent and have choice:
+				 *   1) change it or 2) create/graft new one.
+				 *   If the requested qdisc kind is different
+				 *   than the existing one, then we choose graft.
+				 *   If they are the same then this is "change"
+				 *   operation - just let it fallthrough..
+				 *
+				 *   1. We are allowed to create/graft only
+				 *   if the request is explicitly stating
+				 *   "please create if it doesn't exist".
+				 *
+				 *   2. If the request is to exclusive create
+				 *   then the qdisc tcm_handle is not expected
+				 *   to exist, so that we choose create/graft too.
+				 *
+				 *   3. The last case is when no flags are set.
+				 *   This will happen when for example tc
+				 *   utility issues a "change" command.
+				 *   Alas, it is sort of hole in API, we
+				 *   cannot decide what to do unambiguously.
+				 *   For now we select create/graft.
+				 */
+				if (tca[TCA_KIND] &&
+				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
+					if (req_create_or_replace(n) ||
+					    req_create_exclusive(n))
+						goto create_n_graft;
+					else if (req_change(n))
+						goto create_n_graft2;
+				}
+			}
+		}
+	} else {
+		if (!tcm->tcm_handle) {
+			NL_SET_ERR_MSG(extack, "Handle cannot be zero");
+			return -EINVAL;
+		}
+		q = qdisc_lookup(dev, tcm->tcm_handle);
+	}
+
+	/* Change qdisc parameters */
+	if (!q) {
+		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
+		return -ENOENT;
+	}
+	if (n->nlmsg_flags & NLM_F_EXCL) {
+		NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
+		return -EEXIST;
+	}
+	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
+		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
+		return -EINVAL;
+	}
+	err = qdisc_change(q, tca, extack);
+	if (err == 0)
+		qdisc_notify(net, skb, n, clid, NULL, q, extack);
+	return err;
+
+create_n_graft:
+	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
+		NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
+		return -ENOENT;
+	}
+create_n_graft2:
+	if (clid == TC_H_INGRESS) {
+		if (dev_ingress_queue(dev)) {
+			q = qdisc_create(dev, dev_ingress_queue(dev),
+					 tcm->tcm_parent, tcm->tcm_parent,
+					 tca, &err, extack);
+		} else {
+			NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
+			err = -ENOENT;
+		}
+	} else {
+		struct netdev_queue *dev_queue;
+
+		if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
+			dev_queue = p->ops->cl_ops->select_queue(p, tcm);
+		else if (p)
+			dev_queue = p->dev_queue;
+		else
+			dev_queue = netdev_get_tx_queue(dev, 0);
+
+		q = qdisc_create(dev, dev_queue,
+				 tcm->tcm_parent, tcm->tcm_handle,
+				 tca, &err, extack);
+	}
+	if (q == NULL) {
+		if (err == -EAGAIN)
+			goto replay;
+		return err;
+	}
+
+graft:
+	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
+	if (err) {
+		if (q)
+			qdisc_put(q);
+		return err;
+	}
+
+	return 0;
+}
+
+static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
+			      struct netlink_callback *cb,
+			      int *q_idx_p, int s_q_idx, bool recur,
+			      bool dump_invisible)
+{
+	int ret = 0, q_idx = *q_idx_p;
+	struct Qdisc *q;
+	int b;
+
+	if (!root)
+		return 0;
+
+	q = root;
+	if (q_idx < s_q_idx) {
+		q_idx++;
+	} else {
+		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
+		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
+				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				  RTM_NEWQDISC, NULL) <= 0)
+			goto done;
+		q_idx++;
+	}
+
+	/* If dumping singletons, there is no qdisc_dev(root) and the singleton
+	 * itself has already been dumped.
+	 *
+	 * If we've already dumped the top-level (ingress) qdisc above and the global
+	 * qdisc hashtable, we don't want to hit it again
+	 */
+	if (!qdisc_dev(root) || !recur)
+		goto out;
+
+	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
+		if (q_idx < s_q_idx) {
+			q_idx++;
+			continue;
+		}
+		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
+		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
+				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				  RTM_NEWQDISC, NULL) <= 0)
+			goto done;
+		q_idx++;
+	}
+
+out:
+	*q_idx_p = q_idx;
+	return ret;
+done:
+	ret = -1;
+	goto out;
+}
+
+static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	int idx, q_idx;
+	int s_idx, s_q_idx;
+	struct net_device *dev;
+	const struct nlmsghdr *nlh = cb->nlh;
+	struct nlattr *tca[TCA_MAX + 1];
+	int err;
+
+	s_idx = cb->args[0];
+	s_q_idx = q_idx = cb->args[1];
+
+	idx = 0;
+	ASSERT_RTNL();
+
+	err = nlmsg_parse_deprecated(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
+				     rtm_tca_policy, cb->extack);
+	if (err < 0)
+		return err;
+
+	for_each_netdev(net, dev) {
+		struct netdev_queue *dev_queue;
+
+		if (idx < s_idx)
+			goto cont;
+		if (idx > s_idx)
+			s_q_idx = 0;
+		q_idx = 0;
+
+		if (tc_dump_qdisc_root(rtnl_dereference(dev->qdisc),
+				       skb, cb, &q_idx, s_q_idx,
+				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
+			goto done;
+
+		dev_queue = dev_ingress_queue(dev);
+		if (dev_queue &&
+		    tc_dump_qdisc_root(rtnl_dereference(dev_queue->qdisc_sleeping),
+				       skb, cb, &q_idx, s_q_idx, false,
+				       tca[TCA_DUMP_INVISIBLE]) < 0)
+			goto done;
+
+cont:
+		idx++;
+	}
+
+done:
+	cb->args[0] = idx;
+	cb->args[1] = q_idx;
+
+	return skb->len;
+}
+
+
+
+/************************************************
+ *	Traffic classes manipulation.		*
+ ************************************************/
+
+static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
+			  unsigned long cl, u32 portid, u32 seq, u16 flags,
+			  int event, struct netlink_ext_ack *extack)
+{
+	struct tcmsg *tcm;
+	struct nlmsghdr  *nlh;
+	unsigned char *b = skb_tail_pointer(skb);
+	struct gnet_dump d;
+	const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
+
+	cond_resched();
+	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
+	if (!nlh)
+		goto out_nlmsg_trim;
+	tcm = nlmsg_data(nlh);
+	tcm->tcm_family = AF_UNSPEC;
+	tcm->tcm__pad1 = 0;
+	tcm->tcm__pad2 = 0;
+	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
+	tcm->tcm_parent = q->handle;
+	tcm->tcm_handle = q->handle;
+	tcm->tcm_info = 0;
+	if (nla_put_string(skb, TCA_KIND, q->ops->id))
+		goto nla_put_failure;
+	if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
+		goto nla_put_failure;
+
+	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
+					 NULL, &d, TCA_PAD) < 0)
+		goto nla_put_failure;
+
+	if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
+		goto nla_put_failure;
+
+	if (gnet_stats_finish_copy(&d) < 0)
+		goto nla_put_failure;
+
+	if (extack && extack->_msg &&
+	    nla_put_string(skb, TCA_EXT_WARN_MSG, extack->_msg))
+		goto out_nlmsg_trim;
+
+	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
+
+	return skb->len;
+
+out_nlmsg_trim:
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int tclass_notify(struct net *net, struct sk_buff *oskb,
+			 struct nlmsghdr *n, struct Qdisc *q,
+			 unsigned long cl, int event, struct netlink_ext_ack *extack)
+{
+	struct sk_buff *skb;
+	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+
+	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack) < 0) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
+			      n->nlmsg_flags & NLM_F_ECHO);
+}
+
+static int tclass_del_notify(struct net *net,
+			     const struct Qdisc_class_ops *cops,
+			     struct sk_buff *oskb, struct nlmsghdr *n,
+			     struct Qdisc *q, unsigned long cl,
+			     struct netlink_ext_ack *extack)
+{
+	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
+	struct sk_buff *skb;
+	int err = 0;
+
+	if (!cops->delete)
+		return -EOPNOTSUPP;
+
+	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
+			   RTM_DELTCLASS, extack) < 0) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	err = cops->delete(q, cl, extack);
+	if (err) {
+		kfree_skb(skb);
+		return err;
+	}
+
+	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
+			     n->nlmsg_flags & NLM_F_ECHO);
+	return err;
+}
+
+#ifdef CONFIG_NET_CLS
+
+struct tcf_bind_args {
+	struct tcf_walker w;
+	unsigned long base;
+	unsigned long cl;
+	u32 classid;
+};
+
+static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
+{
+	struct tcf_bind_args *a = (void *)arg;
+
+	if (n && tp->ops->bind_class) {
+		struct Qdisc *q = tcf_block_q(tp->chain->block);
+
+		sch_tree_lock(q);
+		tp->ops->bind_class(n, a->classid, a->cl, q, a->base);
+		sch_tree_unlock(q);
+	}
+	return 0;
+}
+
+struct tc_bind_class_args {
+	struct qdisc_walker w;
+	unsigned long new_cl;
+	u32 portid;
+	u32 clid;
+};
+
+static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl,
+				struct qdisc_walker *w)
+{
+	struct tc_bind_class_args *a = (struct tc_bind_class_args *)w;
+	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
+	struct tcf_block *block;
+	struct tcf_chain *chain;
+
+	block = cops->tcf_block(q, cl, NULL);
+	if (!block)
+		return 0;
+	for (chain = tcf_get_next_chain(block, NULL);
+	     chain;
+	     chain = tcf_get_next_chain(block, chain)) {
+		struct tcf_proto *tp;
+
+		for (tp = tcf_get_next_proto(chain, NULL);
+		     tp; tp = tcf_get_next_proto(chain, tp)) {
+			struct tcf_bind_args arg = {};
+
+			arg.w.fn = tcf_node_bind;
+			arg.classid = a->clid;
+			arg.base = cl;
+			arg.cl = a->new_cl;
+			tp->ops->walk(tp, &arg.w, true);
+		}
+	}
+
+	return 0;
+}
+
+static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
+			   unsigned long new_cl)
+{
+	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
+	struct tc_bind_class_args args = {};
+
+	if (!cops->tcf_block)
+		return;
+	args.portid = portid;
+	args.clid = clid;
+	args.new_cl = new_cl;
+	args.w.fn = tc_bind_class_walker;
+	q->ops->cl_ops->walk(q, &args.w);
+}
+
+#else
+
+static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
+			   unsigned long new_cl)
+{
+}
+
+#endif
+
+static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
+			 struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tcmsg *tcm = nlmsg_data(n);
+	struct nlattr *tca[TCA_MAX + 1];
+	struct net_device *dev;
+	struct Qdisc *q = NULL;
+	const struct Qdisc_class_ops *cops;
+	unsigned long cl = 0;
+	unsigned long new_cl;
+	u32 portid;
+	u32 clid;
+	u32 qid;
+	int err;
+
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
+				     rtm_tca_policy, extack);
+	if (err < 0)
+		return err;
+
+	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+	if (!dev)
+		return -ENODEV;
+
+	/*
+	   parent == TC_H_UNSPEC - unspecified parent.
+	   parent == TC_H_ROOT   - class is root, which has no parent.
+	   parent == X:0	 - parent is root class.
+	   parent == X:Y	 - parent is a node in hierarchy.
+	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.
+
+	   handle == 0:0	 - generate handle from kernel pool.
+	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
+	   handle == X:Y	 - clear.
+	   handle == X:0	 - root class.
+	 */
+
+	/* Step 1. Determine qdisc handle X:0 */
+
+	portid = tcm->tcm_parent;
+	clid = tcm->tcm_handle;
+	qid = TC_H_MAJ(clid);
+
+	if (portid != TC_H_ROOT) {
+		u32 qid1 = TC_H_MAJ(portid);
+
+		if (qid && qid1) {
+			/* If both majors are known, they must be identical. */
+			if (qid != qid1)
+				return -EINVAL;
+		} else if (qid1) {
+			qid = qid1;
+		} else if (qid == 0)
+			qid = rtnl_dereference(dev->qdisc)->handle;
+
+		/* Now qid is genuine qdisc handle consistent
+		 * both with parent and child.
+		 *
+		 * TC_H_MAJ(portid) still may be unspecified, complete it now.
+		 */
+		if (portid)
+			portid = TC_H_MAKE(qid, portid);
+	} else {
+		if (qid == 0)
+			qid = rtnl_dereference(dev->qdisc)->handle;
+	}
+
+	/* OK. Locate qdisc */
+	q = qdisc_lookup(dev, qid);
+	if (!q)
+		return -ENOENT;
+
+	/* An check that it supports classes */
+	cops = q->ops->cl_ops;
+	if (cops == NULL)
+		return -EINVAL;
+
+	/* Now try to get class */
+	if (clid == 0) {
+		if (portid == TC_H_ROOT)
+			clid = qid;
+	} else
+		clid = TC_H_MAKE(qid, clid);
+
+	if (clid)
+		cl = cops->find(q, clid);
+
+	if (cl == 0) {
+		err = -ENOENT;
+		if (n->nlmsg_type != RTM_NEWTCLASS ||
+		    !(n->nlmsg_flags & NLM_F_CREATE))
+			goto out;
+	} else {
+		switch (n->nlmsg_type) {
+		case RTM_NEWTCLASS:
+			err = -EEXIST;
+			if (n->nlmsg_flags & NLM_F_EXCL)
+				goto out;
+			break;
+		case RTM_DELTCLASS:
+			err = tclass_del_notify(net, cops, skb, n, q, cl, extack);
+			/* Unbind the class with flilters with 0 */
+			tc_bind_tclass(q, portid, clid, 0);
+			goto out;
+		case RTM_GETTCLASS:
+			err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS, extack);
+			goto out;
+		default:
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
+	if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
+		NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
+		return -EOPNOTSUPP;
+	}
+
+	new_cl = cl;
+	err = -EOPNOTSUPP;
+	if (cops->change)
+		err = cops->change(q, clid, portid, tca, &new_cl, extack);
+	if (err == 0) {
+		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS, extack);
+		/* We just create a new class, need to do reverse binding. */
+		if (cl != new_cl)
+			tc_bind_tclass(q, portid, clid, new_cl);
+	}
+out:
+	return err;
+}
+
+struct qdisc_dump_args {
+	struct qdisc_walker	w;
+	struct sk_buff		*skb;
+	struct netlink_callback	*cb;
+};
+
+static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
+			    struct qdisc_walker *arg)
+{
+	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;
+
+	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
+			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
+			      RTM_NEWTCLASS, NULL);
+}
+
+static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
+				struct tcmsg *tcm, struct netlink_callback *cb,
+				int *t_p, int s_t)
+{
+	struct qdisc_dump_args arg;
+
+	if (tc_qdisc_dump_ignore(q, false) ||
+	    *t_p < s_t || !q->ops->cl_ops ||
+	    (tcm->tcm_parent &&
+	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
+		(*t_p)++;
+		return 0;
+	}
+	if (*t_p > s_t)
+		memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
+	arg.w.fn = qdisc_class_dump;
+	arg.skb = skb;
+	arg.cb = cb;
+	arg.w.stop  = 0;
+	arg.w.skip = cb->args[1];
+	arg.w.count = 0;
+	q->ops->cl_ops->walk(q, &arg.w);
+	cb->args[1] = arg.w.count;
+	if (arg.w.stop)
+		return -1;
+	(*t_p)++;
+	return 0;
+}
+
+static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
+			       struct tcmsg *tcm, struct netlink_callback *cb,
+			       int *t_p, int s_t, bool recur)
+{
+	struct Qdisc *q;
+	int b;
+
+	if (!root)
+		return 0;
+
+	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
+		return -1;
+
+	if (!qdisc_dev(root) || !recur)
+		return 0;
+
+	if (tcm->tcm_parent) {
+		q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
+		if (q && q != root &&
+		    tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
+			return -1;
+		return 0;
+	}
+	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
+		if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct tcmsg *tcm = nlmsg_data(cb->nlh);
+	struct net *net = sock_net(skb->sk);
+	struct netdev_queue *dev_queue;
+	struct net_device *dev;
+	int t, s_t;
+
+	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
+		return 0;
+	dev = dev_get_by_index(net, tcm->tcm_ifindex);
+	if (!dev)
+		return 0;
+
+	s_t = cb->args[0];
+	t = 0;
+
+	if (tc_dump_tclass_root(rtnl_dereference(dev->qdisc),
+				skb, tcm, cb, &t, s_t, true) < 0)
+		goto done;
+
+	dev_queue = dev_ingress_queue(dev);
+	if (dev_queue &&
+	    tc_dump_tclass_root(rtnl_dereference(dev_queue->qdisc_sleeping),
+				skb, tcm, cb, &t, s_t, false) < 0)
+		goto done;
+
+done:
+	cb->args[0] = t;
+
+	dev_put(dev);
+	return skb->len;
+}
+
+#ifdef CONFIG_PROC_FS
+static int psched_show(struct seq_file *seq, void *v)
+{
+	seq_printf(seq, "%08x %08x %08x %08x\n",
+		   (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
+		   1000000,
+		   (u32)NSEC_PER_SEC / hrtimer_resolution);
+
+	return 0;
+}
+
+static int __net_init psched_net_init(struct net *net)
+{
+	struct proc_dir_entry *e;
+
+	e = proc_create_single("psched", 0, net->proc_net, psched_show);
+	if (e == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __net_exit psched_net_exit(struct net *net)
+{
+	remove_proc_entry("psched", net->proc_net);
+}
+#else
+static int __net_init psched_net_init(struct net *net)
+{
+	return 0;
+}
+
+static void __net_exit psched_net_exit(struct net *net)
+{
+}
+#endif
+
+static struct pernet_operations psched_net_ops = {
+	.init = psched_net_init,
+	.exit = psched_net_exit,
+};
+
+static int __init pktsched_init(void)
+{
+	int err;
+
+	err = register_pernet_subsys(&psched_net_ops);
+	if (err) {
+		pr_err("pktsched_init: "
+		       "cannot initialize per netns operations\n");
+		return err;
+	}
+
+	register_qdisc(&pfifo_fast_ops);
+	register_qdisc(&pfifo_qdisc_ops);
+	register_qdisc(&bfifo_qdisc_ops);
+	register_qdisc(&pfifo_head_drop_qdisc_ops);
+	register_qdisc(&mq_qdisc_ops);
+	register_qdisc(&noqueue_qdisc_ops);
+
+	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
+	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
+	rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
+		      0);
+	rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
+	rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
+	rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
+		      0);
+
+	return 0;
+}
+
+subsys_initcall(pktsched_init);