1 files changed, 962 insertions, 0 deletions

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
new file mode 100644
index 000000000000..206e4dbed12f
--- /dev/null
+++ b/net/sched/sch_taprio.c
@@ -0,0 +1,962 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* net/sched/sch_taprio.c	 Time Aware Priority Scheduler
+ *
+ * Authors:	Vinicius Costa Gomes <vinicius.gomes@intel.com>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
+#include <net/sch_generic.h>
+
+#define TAPRIO_ALL_GATES_OPEN -1
+
+struct sched_entry {
+	struct list_head list;
+
+	/* The instant that this entry "closes" and the next one
+	 * should open, the qdisc will make some effort so that no
+	 * packet leaves after this time.
+	 */
+	ktime_t close_time;
+	atomic_t budget;
+	int index;
+	u32 gate_mask;
+	u32 interval;
+	u8 command;
+};
+
+struct taprio_sched {
+	struct Qdisc **qdiscs;
+	struct Qdisc *root;
+	s64 base_time;
+	int clockid;
+	int picos_per_byte; /* Using picoseconds because for 10Gbps+
+			     * speeds it's sub-nanoseconds per byte
+			     */
+	size_t num_entries;
+
+	/* Protects the update side of the RCU protected current_entry */
+	spinlock_t current_entry_lock;
+	struct sched_entry __rcu *current_entry;
+	struct list_head entries;
+	ktime_t (*get_time)(void);
+	struct hrtimer advance_timer;
+};
+
+static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+			  struct sk_buff **to_free)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct Qdisc *child;
+	int queue;
+
+	queue = skb_get_queue_mapping(skb);
+
+	child = q->qdiscs[queue];
+	if (unlikely(!child))
+		return qdisc_drop(skb, sch, to_free);
+
+	qdisc_qstats_backlog_inc(sch, skb);
+	sch->q.qlen++;
+
+	return qdisc_enqueue(skb, child, to_free);
+}
+
+static struct sk_buff *taprio_peek(struct Qdisc *sch)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct sched_entry *entry;
+	struct sk_buff *skb;
+	u32 gate_mask;
+	int i;
+
+	rcu_read_lock();
+	entry = rcu_dereference(q->current_entry);
+	gate_mask = entry ? entry->gate_mask : -1;
+	rcu_read_unlock();
+
+	if (!gate_mask)
+		return NULL;
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct Qdisc *child = q->qdiscs[i];
+		int prio;
+		u8 tc;
+
+		if (unlikely(!child))
+			continue;
+
+		skb = child->ops->peek(child);
+		if (!skb)
+			continue;
+
+		prio = skb->priority;
+		tc = netdev_get_prio_tc_map(dev, prio);
+
+		if (!(gate_mask & BIT(tc)))
+			return NULL;
+
+		return skb;
+	}
+
+	return NULL;
+}
+
+static inline int length_to_duration(struct taprio_sched *q, int len)
+{
+	return (len * q->picos_per_byte) / 1000;
+}
+
+static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct sched_entry *entry;
+	struct sk_buff *skb;
+	u32 gate_mask;
+	int i;
+
+	rcu_read_lock();
+	entry = rcu_dereference(q->current_entry);
+	/* if there's no entry, it means that the schedule didn't
+	 * start yet, so force all gates to be open, this is in
+	 * accordance to IEEE 802.1Qbv-2015 Section 8.6.9.4.5
+	 * "AdminGateSates"
+	 */
+	gate_mask = entry ? entry->gate_mask : TAPRIO_ALL_GATES_OPEN;
+	rcu_read_unlock();
+
+	if (!gate_mask)
+		return NULL;
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct Qdisc *child = q->qdiscs[i];
+		ktime_t guard;
+		int prio;
+		int len;
+		u8 tc;
+
+		if (unlikely(!child))
+			continue;
+
+		skb = child->ops->peek(child);
+		if (!skb)
+			continue;
+
+		prio = skb->priority;
+		tc = netdev_get_prio_tc_map(dev, prio);
+
+		if (!(gate_mask & BIT(tc)))
+			continue;
+
+		len = qdisc_pkt_len(skb);
+		guard = ktime_add_ns(q->get_time(),
+				     length_to_duration(q, len));
+
+		/* In the case that there's no gate entry, there's no
+		 * guard band ...
+		 */
+		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
+		    ktime_after(guard, entry->close_time))
+			return NULL;
+
+		/* ... and no budget. */
+		if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
+		    atomic_sub_return(len, &entry->budget) < 0)
+			return NULL;
+
+		skb = child->ops->dequeue(child);
+		if (unlikely(!skb))
+			return NULL;
+
+		qdisc_bstats_update(sch, skb);
+		qdisc_qstats_backlog_dec(sch, skb);
+		sch->q.qlen--;
+
+		return skb;
+	}
+
+	return NULL;
+}
+
+static bool should_restart_cycle(const struct taprio_sched *q,
+				 const struct sched_entry *entry)
+{
+	WARN_ON(!entry);
+
+	return list_is_last(&entry->list, &q->entries);
+}
+
+static enum hrtimer_restart advance_sched(struct hrtimer *timer)
+{
+	struct taprio_sched *q = container_of(timer, struct taprio_sched,
+					      advance_timer);
+	struct sched_entry *entry, *next;
+	struct Qdisc *sch = q->root;
+	ktime_t close_time;
+
+	spin_lock(&q->current_entry_lock);
+	entry = rcu_dereference_protected(q->current_entry,
+					  lockdep_is_held(&q->current_entry_lock));
+
+	/* This is the case that it's the first time that the schedule
+	 * runs, so it only happens once per schedule. The first entry
+	 * is pre-calculated during the schedule initialization.
+	 */
+	if (unlikely(!entry)) {
+		next = list_first_entry(&q->entries, struct sched_entry,
+					list);
+		close_time = next->close_time;
+		goto first_run;
+	}
+
+	if (should_restart_cycle(q, entry))
+		next = list_first_entry(&q->entries, struct sched_entry,
+					list);
+	else
+		next = list_next_entry(entry, list);
+
+	close_time = ktime_add_ns(entry->close_time, next->interval);
+
+	next->close_time = close_time;
+	atomic_set(&next->budget,
+		   (next->interval * 1000) / q->picos_per_byte);
+
+first_run:
+	rcu_assign_pointer(q->current_entry, next);
+	spin_unlock(&q->current_entry_lock);
+
+	hrtimer_set_expires(&q->advance_timer, close_time);
+
+	rcu_read_lock();
+	__netif_schedule(sch);
+	rcu_read_unlock();
+
+	return HRTIMER_RESTART;
+}
+
+static const struct nla_policy entry_policy[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = {
+	[TCA_TAPRIO_SCHED_ENTRY_INDEX]	   = { .type = NLA_U32 },
+	[TCA_TAPRIO_SCHED_ENTRY_CMD]	   = { .type = NLA_U8 },
+	[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK] = { .type = NLA_U32 },
+	[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]  = { .type = NLA_U32 },
+};
+
+static const struct nla_policy entry_list_policy[TCA_TAPRIO_SCHED_MAX + 1] = {
+	[TCA_TAPRIO_SCHED_ENTRY] = { .type = NLA_NESTED },
+};
+
+static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
+	[TCA_TAPRIO_ATTR_PRIOMAP]	       = {
+		.len = sizeof(struct tc_mqprio_qopt)
+	},
+	[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST]     = { .type = NLA_NESTED },
+	[TCA_TAPRIO_ATTR_SCHED_BASE_TIME]      = { .type = NLA_S64 },
+	[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY]   = { .type = NLA_NESTED },
+	[TCA_TAPRIO_ATTR_SCHED_CLOCKID]        = { .type = NLA_S32 },
+};
+
+static int fill_sched_entry(struct nlattr **tb, struct sched_entry *entry,
+			    struct netlink_ext_ack *extack)
+{
+	u32 interval = 0;
+
+	if (tb[TCA_TAPRIO_SCHED_ENTRY_CMD])
+		entry->command = nla_get_u8(
+			tb[TCA_TAPRIO_SCHED_ENTRY_CMD]);
+
+	if (tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK])
+		entry->gate_mask = nla_get_u32(
+			tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK]);
+
+	if (tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL])
+		interval = nla_get_u32(
+			tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]);
+
+	if (interval == 0) {
+		NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
+		return -EINVAL;
+	}
+
+	entry->interval = interval;
+
+	return 0;
+}
+
+static int parse_sched_entry(struct nlattr *n, struct sched_entry *entry,
+			     int index, struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = { };
+	int err;
+
+	err = nla_parse_nested(tb, TCA_TAPRIO_SCHED_ENTRY_MAX, n,
+			       entry_policy, NULL);
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
+		return -EINVAL;
+	}
+
+	entry->index = index;
+
+	return fill_sched_entry(tb, entry, extack);
+}
+
+/* Returns the number of entries in case of success */
+static int parse_sched_single_entry(struct nlattr *n,
+				    struct taprio_sched *q,
+				    struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb_entry[TCA_TAPRIO_SCHED_ENTRY_MAX + 1] = { };
+	struct nlattr *tb_list[TCA_TAPRIO_SCHED_MAX + 1] = { };
+	struct sched_entry *entry;
+	bool found = false;
+	u32 index;
+	int err;
+
+	err = nla_parse_nested(tb_list, TCA_TAPRIO_SCHED_MAX,
+			       n, entry_list_policy, NULL);
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
+		return -EINVAL;
+	}
+
+	if (!tb_list[TCA_TAPRIO_SCHED_ENTRY]) {
+		NL_SET_ERR_MSG(extack, "Single-entry must include an entry");
+		return -EINVAL;
+	}
+
+	err = nla_parse_nested(tb_entry, TCA_TAPRIO_SCHED_ENTRY_MAX,
+			       tb_list[TCA_TAPRIO_SCHED_ENTRY],
+			       entry_policy, NULL);
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Could not parse nested entry");
+		return -EINVAL;
+	}
+
+	if (!tb_entry[TCA_TAPRIO_SCHED_ENTRY_INDEX]) {
+		NL_SET_ERR_MSG(extack, "Entry must specify an index\n");
+		return -EINVAL;
+	}
+
+	index = nla_get_u32(tb_entry[TCA_TAPRIO_SCHED_ENTRY_INDEX]);
+	if (index >= q->num_entries) {
+		NL_SET_ERR_MSG(extack, "Index for single entry exceeds number of entries in schedule");
+		return -EINVAL;
+	}
+
+	list_for_each_entry(entry, &q->entries, list) {
+		if (entry->index == index) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		NL_SET_ERR_MSG(extack, "Could not find entry");
+		return -ENOENT;
+	}
+
+	err = fill_sched_entry(tb_entry, entry, extack);
+	if (err < 0)
+		return err;
+
+	return q->num_entries;
+}
+
+static int parse_sched_list(struct nlattr *list,
+			    struct taprio_sched *q,
+			    struct netlink_ext_ack *extack)
+{
+	struct nlattr *n;
+	int err, rem;
+	int i = 0;
+
+	if (!list)
+		return -EINVAL;
+
+	nla_for_each_nested(n, list, rem) {
+		struct sched_entry *entry;
+
+		if (nla_type(n) != TCA_TAPRIO_SCHED_ENTRY) {
+			NL_SET_ERR_MSG(extack, "Attribute is not of type 'entry'");
+			continue;
+		}
+
+		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+		if (!entry) {
+			NL_SET_ERR_MSG(extack, "Not enough memory for entry");
+			return -ENOMEM;
+		}
+
+		err = parse_sched_entry(n, entry, i, extack);
+		if (err < 0) {
+			kfree(entry);
+			return err;
+		}
+
+		list_add_tail(&entry->list, &q->entries);
+		i++;
+	}
+
+	q->num_entries = i;
+
+	return i;
+}
+
+/* Returns the number of entries in case of success */
+static int parse_taprio_opt(struct nlattr **tb, struct taprio_sched *q,
+			    struct netlink_ext_ack *extack)
+{
+	int err = 0;
+	int clockid;
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST] &&
+	    tb[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY])
+		return -EINVAL;
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY] && q->num_entries == 0)
+		return -EINVAL;
+
+	if (q->clockid == -1 && !tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID])
+		return -EINVAL;
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME])
+		q->base_time = nla_get_s64(
+			tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME]);
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]) {
+		clockid = nla_get_s32(tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]);
+
+		/* We only support static clockids and we don't allow
+		 * for it to be modified after the first init.
+		 */
+		if (clockid < 0 || (q->clockid != -1 && q->clockid != clockid))
+			return -EINVAL;
+
+		q->clockid = clockid;
+	}
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST])
+		err = parse_sched_list(
+			tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST], q, extack);
+	else if (tb[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY])
+		err = parse_sched_single_entry(
+			tb[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY], q, extack);
+
+	/* parse_sched_* return the number of entries in the schedule,
+	 * a schedule with zero entries is an error.
+	 */
+	if (err == 0) {
+		NL_SET_ERR_MSG(extack, "The schedule should contain at least one entry");
+		return -EINVAL;
+	}
+
+	return err;
+}
+
+static int taprio_parse_mqprio_opt(struct net_device *dev,
+				   struct tc_mqprio_qopt *qopt,
+				   struct netlink_ext_ack *extack)
+{
+	int i, j;
+
+	if (!qopt) {
+		NL_SET_ERR_MSG(extack, "'mqprio' configuration is necessary");
+		return -EINVAL;
+	}
+
+	/* Verify num_tc is not out of max range */
+	if (qopt->num_tc > TC_MAX_QUEUE) {
+		NL_SET_ERR_MSG(extack, "Number of traffic classes is outside valid range");
+		return -EINVAL;
+	}
+
+	/* taprio imposes that traffic classes map 1:n to tx queues */
+	if (qopt->num_tc > dev->num_tx_queues) {
+		NL_SET_ERR_MSG(extack, "Number of traffic classes is greater than number of HW queues");
+		return -EINVAL;
+	}
+
+	/* Verify priority mapping uses valid tcs */
+	for (i = 0; i < TC_BITMASK + 1; i++) {
+		if (qopt->prio_tc_map[i] >= qopt->num_tc) {
+			NL_SET_ERR_MSG(extack, "Invalid traffic class in priority to traffic class mapping");
+			return -EINVAL;
+		}
+	}
+
+	for (i = 0; i < qopt->num_tc; i++) {
+		unsigned int last = qopt->offset[i] + qopt->count[i];
+
+		/* Verify the queue count is in tx range being equal to the
+		 * real_num_tx_queues indicates the last queue is in use.
+		 */
+		if (qopt->offset[i] >= dev->num_tx_queues ||
+		    !qopt->count[i] ||
+		    last > dev->real_num_tx_queues) {
+			NL_SET_ERR_MSG(extack, "Invalid queue in traffic class to queue mapping");
+			return -EINVAL;
+		}
+
+		/* Verify that the offset and counts do not overlap */
+		for (j = i + 1; j < qopt->num_tc; j++) {
+			if (last > qopt->offset[j]) {
+				NL_SET_ERR_MSG(extack, "Detected overlap in the traffic class to queue mapping");
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static ktime_t taprio_get_start_time(struct Qdisc *sch)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct sched_entry *entry;
+	ktime_t now, base, cycle;
+	s64 n;
+
+	base = ns_to_ktime(q->base_time);
+	cycle = 0;
+
+	/* Calculate the cycle_time, by summing all the intervals.
+	 */
+	list_for_each_entry(entry, &q->entries, list)
+		cycle = ktime_add_ns(cycle, entry->interval);
+
+	if (!cycle)
+		return base;
+
+	now = q->get_time();
+
+	if (ktime_after(base, now))
+		return base;
+
+	/* Schedule the start time for the beginning of the next
+	 * cycle.
+	 */
+	n = div64_s64(ktime_sub_ns(now, base), cycle);
+
+	return ktime_add_ns(base, (n + 1) * cycle);
+}
+
+static void taprio_start_sched(struct Qdisc *sch, ktime_t start)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct sched_entry *first;
+	unsigned long flags;
+
+	spin_lock_irqsave(&q->current_entry_lock, flags);
+
+	first = list_first_entry(&q->entries, struct sched_entry,
+				 list);
+
+	first->close_time = ktime_add_ns(start, first->interval);
+	atomic_set(&first->budget,
+		   (first->interval * 1000) / q->picos_per_byte);
+	rcu_assign_pointer(q->current_entry, NULL);
+
+	spin_unlock_irqrestore(&q->current_entry_lock, flags);
+
+	hrtimer_start(&q->advance_timer, start, HRTIMER_MODE_ABS);
+}
+
+static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
+			 struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[TCA_TAPRIO_ATTR_MAX + 1] = { };
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct tc_mqprio_qopt *mqprio = NULL;
+	struct ethtool_link_ksettings ecmd;
+	int i, err, size;
+	s64 link_speed;
+	ktime_t start;
+
+	err = nla_parse_nested(tb, TCA_TAPRIO_ATTR_MAX, opt,
+			       taprio_policy, extack);
+	if (err < 0)
+		return err;
+
+	err = -EINVAL;
+	if (tb[TCA_TAPRIO_ATTR_PRIOMAP])
+		mqprio = nla_data(tb[TCA_TAPRIO_ATTR_PRIOMAP]);
+
+	err = taprio_parse_mqprio_opt(dev, mqprio, extack);
+	if (err < 0)
+		return err;
+
+	/* A schedule with less than one entry is an error */
+	size = parse_taprio_opt(tb, q, extack);
+	if (size < 0)
+		return size;
+
+	hrtimer_init(&q->advance_timer, q->clockid, HRTIMER_MODE_ABS);
+	q->advance_timer.function = advance_sched;
+
+	switch (q->clockid) {
+	case CLOCK_REALTIME:
+		q->get_time = ktime_get_real;
+		break;
+	case CLOCK_MONOTONIC:
+		q->get_time = ktime_get;
+		break;
+	case CLOCK_BOOTTIME:
+		q->get_time = ktime_get_boottime;
+		break;
+	case CLOCK_TAI:
+		q->get_time = ktime_get_clocktai;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *dev_queue;
+		struct Qdisc *qdisc;
+
+		dev_queue = netdev_get_tx_queue(dev, i);
+		qdisc = qdisc_create_dflt(dev_queue,
+					  &pfifo_qdisc_ops,
+					  TC_H_MAKE(TC_H_MAJ(sch->handle),
+						    TC_H_MIN(i + 1)),
+					  extack);
+		if (!qdisc)
+			return -ENOMEM;
+
+		if (i < dev->real_num_tx_queues)
+			qdisc_hash_add(qdisc, false);
+
+		q->qdiscs[i] = qdisc;
+	}
+
+	if (mqprio) {
+		netdev_set_num_tc(dev, mqprio->num_tc);
+		for (i = 0; i < mqprio->num_tc; i++)
+			netdev_set_tc_queue(dev, i,
+					    mqprio->count[i],
+					    mqprio->offset[i]);
+
+		/* Always use supplied priority mappings */
+		for (i = 0; i < TC_BITMASK + 1; i++)
+			netdev_set_prio_tc_map(dev, i,
+					       mqprio->prio_tc_map[i]);
+	}
+
+	if (!__ethtool_get_link_ksettings(dev, &ecmd))
+		link_speed = ecmd.base.speed;
+	else
+		link_speed = SPEED_1000;
+
+	q->picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
+				      link_speed * 1000 * 1000);
+
+	start = taprio_get_start_time(sch);
+	if (!start)
+		return 0;
+
+	taprio_start_sched(sch, start);
+
+	return 0;
+}
+
+static void taprio_destroy(struct Qdisc *sch)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct sched_entry *entry, *n;
+	unsigned int i;
+
+	hrtimer_cancel(&q->advance_timer);
+
+	if (q->qdiscs) {
+		for (i = 0; i < dev->num_tx_queues && q->qdiscs[i]; i++)
+			qdisc_put(q->qdiscs[i]);
+
+		kfree(q->qdiscs);
+	}
+	q->qdiscs = NULL;
+
+	netdev_set_num_tc(dev, 0);
+
+	list_for_each_entry_safe(entry, n, &q->entries, list) {
+		list_del(&entry->list);
+		kfree(entry);
+	}
+}
+
+static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
+		       struct netlink_ext_ack *extack)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+
+	INIT_LIST_HEAD(&q->entries);
+	spin_lock_init(&q->current_entry_lock);
+
+	/* We may overwrite the configuration later */
+	hrtimer_init(&q->advance_timer, CLOCK_TAI, HRTIMER_MODE_ABS);
+
+	q->root = sch;
+
+	/* We only support static clockids. Use an invalid value as default
+	 * and get the valid one on taprio_change().
+	 */
+	q->clockid = -1;
+
+	if (sch->parent != TC_H_ROOT)
+		return -EOPNOTSUPP;
+
+	if (!netif_is_multiqueue(dev))
+		return -EOPNOTSUPP;
+
+	/* pre-allocate qdisc, attachment can't fail */
+	q->qdiscs = kcalloc(dev->num_tx_queues,
+			    sizeof(q->qdiscs[0]),
+			    GFP_KERNEL);
+
+	if (!q->qdiscs)
+		return -ENOMEM;
+
+	if (!opt)
+		return -EINVAL;
+
+	return taprio_change(sch, opt, extack);
+}
+
+static struct netdev_queue *taprio_queue_get(struct Qdisc *sch,
+					     unsigned long cl)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	unsigned long ntx = cl - 1;
+
+	if (ntx >= dev->num_tx_queues)
+		return NULL;
+
+	return netdev_get_tx_queue(dev, ntx);
+}
+
+static int taprio_graft(struct Qdisc *sch, unsigned long cl,
+			struct Qdisc *new, struct Qdisc **old,
+			struct netlink_ext_ack *extack)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+
+	if (!dev_queue)
+		return -EINVAL;
+
+	if (dev->flags & IFF_UP)
+		dev_deactivate(dev);
+
+	*old = q->qdiscs[cl - 1];
+	q->qdiscs[cl - 1] = new;
+
+	if (new)
+		new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
+
+	if (dev->flags & IFF_UP)
+		dev_activate(dev);
+
+	return 0;
+}
+
+static int dump_entry(struct sk_buff *msg,
+		      const struct sched_entry *entry)
+{
+	struct nlattr *item;
+
+	item = nla_nest_start(msg, TCA_TAPRIO_SCHED_ENTRY);
+	if (!item)
+		return -ENOSPC;
+
+	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_INDEX, entry->index))
+		goto nla_put_failure;
+
+	if (nla_put_u8(msg, TCA_TAPRIO_SCHED_ENTRY_CMD, entry->command))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_GATE_MASK,
+			entry->gate_mask))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, TCA_TAPRIO_SCHED_ENTRY_INTERVAL,
+			entry->interval))
+		goto nla_put_failure;
+
+	return nla_nest_end(msg, item);
+
+nla_put_failure:
+	nla_nest_cancel(msg, item);
+	return -1;
+}
+
+static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	struct tc_mqprio_qopt opt = { 0 };
+	struct nlattr *nest, *entry_list;
+	struct sched_entry *entry;
+	unsigned int i;
+
+	opt.num_tc = netdev_get_num_tc(dev);
+	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
+
+	for (i = 0; i < netdev_get_num_tc(dev); i++) {
+		opt.count[i] = dev->tc_to_txq[i].count;
+		opt.offset[i] = dev->tc_to_txq[i].offset;
+	}
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (!nest)
+		return -ENOSPC;
+
+	if (nla_put(skb, TCA_TAPRIO_ATTR_PRIOMAP, sizeof(opt), &opt))
+		goto options_error;
+
+	if (nla_put_s64(skb, TCA_TAPRIO_ATTR_SCHED_BASE_TIME,
+			q->base_time, TCA_TAPRIO_PAD))
+		goto options_error;
+
+	if (nla_put_s32(skb, TCA_TAPRIO_ATTR_SCHED_CLOCKID, q->clockid))
+		goto options_error;
+
+	entry_list = nla_nest_start(skb, TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST);
+	if (!entry_list)
+		goto options_error;
+
+	list_for_each_entry(entry, &q->entries, list) {
+		if (dump_entry(skb, entry) < 0)
+			goto options_error;
+	}
+
+	nla_nest_end(skb, entry_list);
+
+	return nla_nest_end(skb, nest);
+
+options_error:
+	nla_nest_cancel(skb, nest);
+	return -1;
+}
+
+static struct Qdisc *taprio_leaf(struct Qdisc *sch, unsigned long cl)
+{
+	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+
+	if (!dev_queue)
+		return NULL;
+
+	return dev_queue->qdisc_sleeping;
+}
+
+static unsigned long taprio_find(struct Qdisc *sch, u32 classid)
+{
+	unsigned int ntx = TC_H_MIN(classid);
+
+	if (!taprio_queue_get(sch, ntx))
+		return 0;
+	return ntx;
+}
+
+static int taprio_dump_class(struct Qdisc *sch, unsigned long cl,
+			     struct sk_buff *skb, struct tcmsg *tcm)
+{
+	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+
+	tcm->tcm_parent = TC_H_ROOT;
+	tcm->tcm_handle |= TC_H_MIN(cl);
+	tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
+
+	return 0;
+}
+
+static int taprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
+				   struct gnet_dump *d)
+	__releases(d->lock)
+	__acquires(d->lock)
+{
+	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+
+	sch = dev_queue->qdisc_sleeping;
+	if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
+	    gnet_stats_copy_queue(d, NULL, &sch->qstats, sch->q.qlen) < 0)
+		return -1;
+	return 0;
+}
+
+static void taprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	unsigned long ntx;
+
+	if (arg->stop)
+		return;
+
+	arg->count = arg->skip;
+	for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
+		if (arg->fn(sch, ntx + 1, arg) < 0) {
+			arg->stop = 1;
+			break;
+		}
+		arg->count++;
+	}
+}
+
+static struct netdev_queue *taprio_select_queue(struct Qdisc *sch,
+						struct tcmsg *tcm)
+{
+	return taprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
+}
+
+static const struct Qdisc_class_ops taprio_class_ops = {
+	.graft		= taprio_graft,
+	.leaf		= taprio_leaf,
+	.find		= taprio_find,
+	.walk		= taprio_walk,
+	.dump		= taprio_dump_class,
+	.dump_stats	= taprio_dump_class_stats,
+	.select_queue	= taprio_select_queue,
+};
+
+static struct Qdisc_ops taprio_qdisc_ops __read_mostly = {
+	.cl_ops		= &taprio_class_ops,
+	.id		= "taprio",
+	.priv_size	= sizeof(struct taprio_sched),
+	.init		= taprio_init,
+	.destroy	= taprio_destroy,
+	.peek		= taprio_peek,
+	.dequeue	= taprio_dequeue,
+	.enqueue	= taprio_enqueue,
+	.dump		= taprio_dump,
+	.owner		= THIS_MODULE,
+};
+
+static int __init taprio_module_init(void)
+{
+	return register_qdisc(&taprio_qdisc_ops);
+}
+
+static void __exit taprio_module_exit(void)
+{
+	unregister_qdisc(&taprio_qdisc_ops);
+}
+
+module_init(taprio_module_init);
+module_exit(taprio_module_exit);
+MODULE_LICENSE("GPL");