Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 936 insertions, 0 deletions

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
new file mode 100644
index 000000000..ba60a8dd5
--- /dev/null
+++ b/net/sched/sch_fq.c
@@ -0,0 +1,936 @@
+/*
+ * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
+ *
+ *  Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *  Meant to be mostly used for locally generated traffic :
+ *  Fast classification depends on skb->sk being set before reaching us.
+ *  If not, (router workload), we use rxhash as fallback, with 32 bits wide hash.
+ *  All packets belonging to a socket are considered as a 'flow'.
+ *
+ *  Flows are dynamically allocated and stored in a hash table of RB trees
+ *  They are also part of one Round Robin 'queues' (new or old flows)
+ *
+ *  Burst avoidance (aka pacing) capability :
+ *
+ *  Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a
+ *  bunch of packets, and this packet scheduler adds delay between
+ *  packets to respect rate limitation.
+ *
+ *  enqueue() :
+ *   - lookup one RB tree (out of 1024 or more) to find the flow.
+ *     If non existent flow, create it, add it to the tree.
+ *     Add skb to the per flow list of skb (fifo).
+ *   - Use a special fifo for high prio packets
+ *
+ *  dequeue() : serves flows in Round Robin
+ *  Note : When a flow becomes empty, we do not immediately remove it from
+ *  rb trees, for performance reasons (its expected to send additional packets,
+ *  or SLAB cache will reuse socket for another flow)
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/string.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+#include <linux/hash.h>
+#include <linux/prefetch.h>
+#include <linux/vmalloc.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/tcp.h>
+
+/*
+ * Per flow structure, dynamically allocated
+ */
+struct fq_flow {
+	struct sk_buff	*head;		/* list of skbs for this flow : first skb */
+	union {
+		struct sk_buff *tail;	/* last skb in the list */
+		unsigned long  age;	/* jiffies when flow was emptied, for gc */
+	};
+	struct rb_node	fq_node;	/* anchor in fq_root[] trees */
+	struct sock	*sk;
+	int		qlen;		/* number of packets in flow queue */
+	int		credit;
+	u32		socket_hash;	/* sk_hash */
+	struct fq_flow *next;		/* next pointer in RR lists, or &detached */
+
+	struct rb_node  rate_node;	/* anchor in q->delayed tree */
+	u64		time_next_packet;
+};
+
+struct fq_flow_head {
+	struct fq_flow *first;
+	struct fq_flow *last;
+};
+
+struct fq_sched_data {
+	struct fq_flow_head new_flows;
+
+	struct fq_flow_head old_flows;
+
+	struct rb_root	delayed;	/* for rate limited flows */
+	u64		time_next_delayed_flow;
+	unsigned long	unthrottle_latency_ns;
+
+	struct fq_flow	internal;	/* for non classified or high prio packets */
+	u32		quantum;
+	u32		initial_quantum;
+	u32		flow_refill_delay;
+	u32		flow_max_rate;	/* optional max rate per flow */
+	u32		flow_plimit;	/* max packets per flow */
+	u32		orphan_mask;	/* mask for orphaned skb */
+	u32		low_rate_threshold;
+	struct rb_root	*fq_root;
+	u8		rate_enable;
+	u8		fq_trees_log;
+
+	u32		flows;
+	u32		inactive_flows;
+	u32		throttled_flows;
+
+	u64		stat_gc_flows;
+	u64		stat_internal_packets;
+	u64		stat_tcp_retrans;
+	u64		stat_throttled;
+	u64		stat_flows_plimit;
+	u64		stat_pkts_too_long;
+	u64		stat_allocation_errors;
+	struct qdisc_watchdog watchdog;
+};
+
+/* special value to mark a detached flow (not on old/new list) */
+static struct fq_flow detached, throttled;
+
+static void fq_flow_set_detached(struct fq_flow *f)
+{
+	f->next = &detached;
+	f->age = jiffies;
+}
+
+static bool fq_flow_is_detached(const struct fq_flow *f)
+{
+	return f->next == &detached;
+}
+
+static bool fq_flow_is_throttled(const struct fq_flow *f)
+{
+	return f->next == &throttled;
+}
+
+static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
+{
+	if (head->first)
+		head->last->next = flow;
+	else
+		head->first = flow;
+	head->last = flow;
+	flow->next = NULL;
+}
+
+static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
+{
+	rb_erase(&f->rate_node, &q->delayed);
+	q->throttled_flows--;
+	fq_flow_add_tail(&q->old_flows, f);
+}
+
+static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
+{
+	struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
+
+	while (*p) {
+		struct fq_flow *aux;
+
+		parent = *p;
+		aux = rb_entry(parent, struct fq_flow, rate_node);
+		if (f->time_next_packet >= aux->time_next_packet)
+			p = &parent->rb_right;
+		else
+			p = &parent->rb_left;
+	}
+	rb_link_node(&f->rate_node, parent, p);
+	rb_insert_color(&f->rate_node, &q->delayed);
+	q->throttled_flows++;
+	q->stat_throttled++;
+
+	f->next = &throttled;
+	if (q->time_next_delayed_flow > f->time_next_packet)
+		q->time_next_delayed_flow = f->time_next_packet;
+}
+
+
+static struct kmem_cache *fq_flow_cachep __read_mostly;
+
+
+/* limit number of collected flows per round */
+#define FQ_GC_MAX 8
+#define FQ_GC_AGE (3*HZ)
+
+static bool fq_gc_candidate(const struct fq_flow *f)
+{
+	return fq_flow_is_detached(f) &&
+	       time_after(jiffies, f->age + FQ_GC_AGE);
+}
+
+static void fq_gc(struct fq_sched_data *q,
+		  struct rb_root *root,
+		  struct sock *sk)
+{
+	struct fq_flow *f, *tofree[FQ_GC_MAX];
+	struct rb_node **p, *parent;
+	int fcnt = 0;
+
+	p = &root->rb_node;
+	parent = NULL;
+	while (*p) {
+		parent = *p;
+
+		f = rb_entry(parent, struct fq_flow, fq_node);
+		if (f->sk == sk)
+			break;
+
+		if (fq_gc_candidate(f)) {
+			tofree[fcnt++] = f;
+			if (fcnt == FQ_GC_MAX)
+				break;
+		}
+
+		if (f->sk > sk)
+			p = &parent->rb_right;
+		else
+			p = &parent->rb_left;
+	}
+
+	q->flows -= fcnt;
+	q->inactive_flows -= fcnt;
+	q->stat_gc_flows += fcnt;
+	while (fcnt) {
+		struct fq_flow *f = tofree[--fcnt];
+
+		rb_erase(&f->fq_node, root);
+		kmem_cache_free(fq_flow_cachep, f);
+	}
+}
+
+static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
+{
+	struct rb_node **p, *parent;
+	struct sock *sk = skb->sk;
+	struct rb_root *root;
+	struct fq_flow *f;
+
+	/* warning: no starvation prevention... */
+	if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
+		return &q->internal;
+
+	/* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
+	 * or a listener (SYNCOOKIE mode)
+	 * 1) request sockets are not full blown,
+	 *    they do not contain sk_pacing_rate
+	 * 2) They are not part of a 'flow' yet
+	 * 3) We do not want to rate limit them (eg SYNFLOOD attack),
+	 *    especially if the listener set SO_MAX_PACING_RATE
+	 * 4) We pretend they are orphaned
+	 */
+	if (!sk || sk_listener(sk)) {
+		unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
+
+		/* By forcing low order bit to 1, we make sure to not
+		 * collide with a local flow (socket pointers are word aligned)
+		 */
+		sk = (struct sock *)((hash << 1) | 1UL);
+		skb_orphan(skb);
+	}
+
+	root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
+
+	if (q->flows >= (2U << q->fq_trees_log) &&
+	    q->inactive_flows > q->flows/2)
+		fq_gc(q, root, sk);
+
+	p = &root->rb_node;
+	parent = NULL;
+	while (*p) {
+		parent = *p;
+
+		f = rb_entry(parent, struct fq_flow, fq_node);
+		if (f->sk == sk) {
+			/* socket might have been reallocated, so check
+			 * if its sk_hash is the same.
+			 * It not, we need to refill credit with
+			 * initial quantum
+			 */
+			if (unlikely(skb->sk &&
+				     f->socket_hash != sk->sk_hash)) {
+				f->credit = q->initial_quantum;
+				f->socket_hash = sk->sk_hash;
+				if (fq_flow_is_throttled(f))
+					fq_flow_unset_throttled(q, f);
+				f->time_next_packet = 0ULL;
+			}
+			return f;
+		}
+		if (f->sk > sk)
+			p = &parent->rb_right;
+		else
+			p = &parent->rb_left;
+	}
+
+	f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
+	if (unlikely(!f)) {
+		q->stat_allocation_errors++;
+		return &q->internal;
+	}
+	fq_flow_set_detached(f);
+	f->sk = sk;
+	if (skb->sk)
+		f->socket_hash = sk->sk_hash;
+	f->credit = q->initial_quantum;
+
+	rb_link_node(&f->fq_node, parent, p);
+	rb_insert_color(&f->fq_node, root);
+
+	q->flows++;
+	q->inactive_flows++;
+	return f;
+}
+
+
+/* remove one skb from head of flow queue */
+static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
+{
+	struct sk_buff *skb = flow->head;
+
+	if (skb) {
+		flow->head = skb->next;
+		skb->next = NULL;
+		flow->qlen--;
+		qdisc_qstats_backlog_dec(sch, skb);
+		sch->q.qlen--;
+	}
+	return skb;
+}
+
+/* We might add in the future detection of retransmits
+ * For the time being, just return false
+ */
+static bool skb_is_retransmit(struct sk_buff *skb)
+{
+	return false;
+}
+
+/* add skb to flow queue
+ * flow queue is a linked list, kind of FIFO, except for TCP retransmits
+ * We special case tcp retransmits to be transmitted before other packets.
+ * We rely on fact that TCP retransmits are unlikely, so we do not waste
+ * a separate queue or a pointer.
+ * head->  [retrans pkt 1]
+ *         [retrans pkt 2]
+ *         [ normal pkt 1]
+ *         [ normal pkt 2]
+ *         [ normal pkt 3]
+ * tail->  [ normal pkt 4]
+ */
+static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
+{
+	struct sk_buff *prev, *head = flow->head;
+
+	skb->next = NULL;
+	if (!head) {
+		flow->head = skb;
+		flow->tail = skb;
+		return;
+	}
+	if (likely(!skb_is_retransmit(skb))) {
+		flow->tail->next = skb;
+		flow->tail = skb;
+		return;
+	}
+
+	/* This skb is a tcp retransmit,
+	 * find the last retrans packet in the queue
+	 */
+	prev = NULL;
+	while (skb_is_retransmit(head)) {
+		prev = head;
+		head = head->next;
+		if (!head)
+			break;
+	}
+	if (!prev) { /* no rtx packet in queue, become the new head */
+		skb->next = flow->head;
+		flow->head = skb;
+	} else {
+		if (prev == flow->tail)
+			flow->tail = skb;
+		else
+			skb->next = prev->next;
+		prev->next = skb;
+	}
+}
+
+static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+		      struct sk_buff **to_free)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct fq_flow *f;
+
+	if (unlikely(sch->q.qlen >= sch->limit))
+		return qdisc_drop(skb, sch, to_free);
+
+	f = fq_classify(skb, q);
+	if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
+		q->stat_flows_plimit++;
+		return qdisc_drop(skb, sch, to_free);
+	}
+
+	f->qlen++;
+	if (skb_is_retransmit(skb))
+		q->stat_tcp_retrans++;
+	qdisc_qstats_backlog_inc(sch, skb);
+	if (fq_flow_is_detached(f)) {
+		struct sock *sk = skb->sk;
+
+		fq_flow_add_tail(&q->new_flows, f);
+		if (time_after(jiffies, f->age + q->flow_refill_delay))
+			f->credit = max_t(u32, f->credit, q->quantum);
+		if (sk && q->rate_enable) {
+			if (unlikely(smp_load_acquire(&sk->sk_pacing_status) !=
+				     SK_PACING_FQ))
+				smp_store_release(&sk->sk_pacing_status,
+						  SK_PACING_FQ);
+		}
+		q->inactive_flows--;
+	}
+
+	/* Note: this overwrites f->age */
+	flow_queue_add(f, skb);
+
+	if (unlikely(f == &q->internal)) {
+		q->stat_internal_packets++;
+	}
+	sch->q.qlen++;
+
+	return NET_XMIT_SUCCESS;
+}
+
+static void fq_check_throttled(struct fq_sched_data *q, u64 now)
+{
+	unsigned long sample;
+	struct rb_node *p;
+
+	if (q->time_next_delayed_flow > now)
+		return;
+
+	/* Update unthrottle latency EWMA.
+	 * This is cheap and can help diagnosing timer/latency problems.
+	 */
+	sample = (unsigned long)(now - q->time_next_delayed_flow);
+	q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
+	q->unthrottle_latency_ns += sample >> 3;
+
+	q->time_next_delayed_flow = ~0ULL;
+	while ((p = rb_first(&q->delayed)) != NULL) {
+		struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node);
+
+		if (f->time_next_packet > now) {
+			q->time_next_delayed_flow = f->time_next_packet;
+			break;
+		}
+		fq_flow_unset_throttled(q, f);
+	}
+}
+
+static struct sk_buff *fq_dequeue(struct Qdisc *sch)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	u64 now = ktime_get_ns();
+	struct fq_flow_head *head;
+	struct sk_buff *skb;
+	struct fq_flow *f;
+	u32 rate, plen;
+
+	skb = fq_dequeue_head(sch, &q->internal);
+	if (skb)
+		goto out;
+	fq_check_throttled(q, now);
+begin:
+	head = &q->new_flows;
+	if (!head->first) {
+		head = &q->old_flows;
+		if (!head->first) {
+			if (q->time_next_delayed_flow != ~0ULL)
+				qdisc_watchdog_schedule_ns(&q->watchdog,
+							   q->time_next_delayed_flow);
+			return NULL;
+		}
+	}
+	f = head->first;
+
+	if (f->credit <= 0) {
+		f->credit += q->quantum;
+		head->first = f->next;
+		fq_flow_add_tail(&q->old_flows, f);
+		goto begin;
+	}
+
+	skb = f->head;
+	if (unlikely(skb && now < f->time_next_packet &&
+		     !skb_is_tcp_pure_ack(skb))) {
+		head->first = f->next;
+		fq_flow_set_throttled(q, f);
+		goto begin;
+	}
+
+	skb = fq_dequeue_head(sch, f);
+	if (!skb) {
+		head->first = f->next;
+		/* force a pass through old_flows to prevent starvation */
+		if ((head == &q->new_flows) && q->old_flows.first) {
+			fq_flow_add_tail(&q->old_flows, f);
+		} else {
+			fq_flow_set_detached(f);
+			q->inactive_flows++;
+		}
+		goto begin;
+	}
+	prefetch(&skb->end);
+	f->credit -= qdisc_pkt_len(skb);
+
+	if (!q->rate_enable)
+		goto out;
+
+	/* Do not pace locally generated ack packets */
+	if (skb_is_tcp_pure_ack(skb))
+		goto out;
+
+	rate = q->flow_max_rate;
+	if (skb->sk)
+		rate = min(skb->sk->sk_pacing_rate, rate);
+
+	if (rate <= q->low_rate_threshold) {
+		f->credit = 0;
+		plen = qdisc_pkt_len(skb);
+	} else {
+		plen = max(qdisc_pkt_len(skb), q->quantum);
+		if (f->credit > 0)
+			goto out;
+	}
+	if (rate != ~0U) {
+		u64 len = (u64)plen * NSEC_PER_SEC;
+
+		if (likely(rate))
+			do_div(len, rate);
+		/* Since socket rate can change later,
+		 * clamp the delay to 1 second.
+		 * Really, providers of too big packets should be fixed !
+		 */
+		if (unlikely(len > NSEC_PER_SEC)) {
+			len = NSEC_PER_SEC;
+			q->stat_pkts_too_long++;
+		}
+		/* Account for schedule/timers drifts.
+		 * f->time_next_packet was set when prior packet was sent,
+		 * and current time (@now) can be too late by tens of us.
+		 */
+		if (f->time_next_packet)
+			len -= min(len/2, now - f->time_next_packet);
+		f->time_next_packet = now + len;
+	}
+out:
+	qdisc_bstats_update(sch, skb);
+	return skb;
+}
+
+static void fq_flow_purge(struct fq_flow *flow)
+{
+	rtnl_kfree_skbs(flow->head, flow->tail);
+	flow->head = NULL;
+	flow->qlen = 0;
+}
+
+static void fq_reset(struct Qdisc *sch)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct rb_root *root;
+	struct rb_node *p;
+	struct fq_flow *f;
+	unsigned int idx;
+
+	sch->q.qlen = 0;
+	sch->qstats.backlog = 0;
+
+	fq_flow_purge(&q->internal);
+
+	if (!q->fq_root)
+		return;
+
+	for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
+		root = &q->fq_root[idx];
+		while ((p = rb_first(root)) != NULL) {
+			f = rb_entry(p, struct fq_flow, fq_node);
+			rb_erase(p, root);
+
+			fq_flow_purge(f);
+
+			kmem_cache_free(fq_flow_cachep, f);
+		}
+	}
+	q->new_flows.first	= NULL;
+	q->old_flows.first	= NULL;
+	q->delayed		= RB_ROOT;
+	q->flows		= 0;
+	q->inactive_flows	= 0;
+	q->throttled_flows	= 0;
+}
+
+static void fq_rehash(struct fq_sched_data *q,
+		      struct rb_root *old_array, u32 old_log,
+		      struct rb_root *new_array, u32 new_log)
+{
+	struct rb_node *op, **np, *parent;
+	struct rb_root *oroot, *nroot;
+	struct fq_flow *of, *nf;
+	int fcnt = 0;
+	u32 idx;
+
+	for (idx = 0; idx < (1U << old_log); idx++) {
+		oroot = &old_array[idx];
+		while ((op = rb_first(oroot)) != NULL) {
+			rb_erase(op, oroot);
+			of = rb_entry(op, struct fq_flow, fq_node);
+			if (fq_gc_candidate(of)) {
+				fcnt++;
+				kmem_cache_free(fq_flow_cachep, of);
+				continue;
+			}
+			nroot = &new_array[hash_ptr(of->sk, new_log)];
+
+			np = &nroot->rb_node;
+			parent = NULL;
+			while (*np) {
+				parent = *np;
+
+				nf = rb_entry(parent, struct fq_flow, fq_node);
+				BUG_ON(nf->sk == of->sk);
+
+				if (nf->sk > of->sk)
+					np = &parent->rb_right;
+				else
+					np = &parent->rb_left;
+			}
+
+			rb_link_node(&of->fq_node, parent, np);
+			rb_insert_color(&of->fq_node, nroot);
+		}
+	}
+	q->flows -= fcnt;
+	q->inactive_flows -= fcnt;
+	q->stat_gc_flows += fcnt;
+}
+
+static void fq_free(void *addr)
+{
+	kvfree(addr);
+}
+
+static int fq_resize(struct Qdisc *sch, u32 log)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct rb_root *array;
+	void *old_fq_root;
+	u32 idx;
+
+	if (q->fq_root && log == q->fq_trees_log)
+		return 0;
+
+	/* If XPS was setup, we can allocate memory on right NUMA node */
+	array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
+			      netdev_queue_numa_node_read(sch->dev_queue));
+	if (!array)
+		return -ENOMEM;
+
+	for (idx = 0; idx < (1U << log); idx++)
+		array[idx] = RB_ROOT;
+
+	sch_tree_lock(sch);
+
+	old_fq_root = q->fq_root;
+	if (old_fq_root)
+		fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
+
+	q->fq_root = array;
+	q->fq_trees_log = log;
+
+	sch_tree_unlock(sch);
+
+	fq_free(old_fq_root);
+
+	return 0;
+}
+
+static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
+	[TCA_FQ_PLIMIT]			= { .type = NLA_U32 },
+	[TCA_FQ_FLOW_PLIMIT]		= { .type = NLA_U32 },
+	[TCA_FQ_QUANTUM]		= { .type = NLA_U32 },
+	[TCA_FQ_INITIAL_QUANTUM]	= { .type = NLA_U32 },
+	[TCA_FQ_RATE_ENABLE]		= { .type = NLA_U32 },
+	[TCA_FQ_FLOW_DEFAULT_RATE]	= { .type = NLA_U32 },
+	[TCA_FQ_FLOW_MAX_RATE]		= { .type = NLA_U32 },
+	[TCA_FQ_BUCKETS_LOG]		= { .type = NLA_U32 },
+	[TCA_FQ_FLOW_REFILL_DELAY]	= { .type = NLA_U32 },
+	[TCA_FQ_ORPHAN_MASK]		= { .type = NLA_U32 },
+	[TCA_FQ_LOW_RATE_THRESHOLD]	= { .type = NLA_U32 },
+};
+
+static int fq_change(struct Qdisc *sch, struct nlattr *opt,
+		     struct netlink_ext_ack *extack)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct nlattr *tb[TCA_FQ_MAX + 1];
+	int err, drop_count = 0;
+	unsigned drop_len = 0;
+	u32 fq_log;
+
+	if (!opt)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy, NULL);
+	if (err < 0)
+		return err;
+
+	sch_tree_lock(sch);
+
+	fq_log = q->fq_trees_log;
+
+	if (tb[TCA_FQ_BUCKETS_LOG]) {
+		u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
+
+		if (nval >= 1 && nval <= ilog2(256*1024))
+			fq_log = nval;
+		else
+			err = -EINVAL;
+	}
+	if (tb[TCA_FQ_PLIMIT])
+		sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
+
+	if (tb[TCA_FQ_FLOW_PLIMIT])
+		q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
+
+	if (tb[TCA_FQ_QUANTUM]) {
+		u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
+
+		if (quantum > 0 && quantum <= (1 << 20)) {
+			q->quantum = quantum;
+		} else {
+			NL_SET_ERR_MSG_MOD(extack, "invalid quantum");
+			err = -EINVAL;
+		}
+	}
+
+	if (tb[TCA_FQ_INITIAL_QUANTUM])
+		q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
+
+	if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
+		pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
+				    nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
+
+	if (tb[TCA_FQ_FLOW_MAX_RATE])
+		q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
+
+	if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
+		q->low_rate_threshold =
+			nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
+
+	if (tb[TCA_FQ_RATE_ENABLE]) {
+		u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
+
+		if (enable <= 1)
+			q->rate_enable = enable;
+		else
+			err = -EINVAL;
+	}
+
+	if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
+		u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
+
+		q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
+	}
+
+	if (tb[TCA_FQ_ORPHAN_MASK])
+		q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
+
+	if (!err) {
+		sch_tree_unlock(sch);
+		err = fq_resize(sch, fq_log);
+		sch_tree_lock(sch);
+	}
+	while (sch->q.qlen > sch->limit) {
+		struct sk_buff *skb = fq_dequeue(sch);
+
+		if (!skb)
+			break;
+		drop_len += qdisc_pkt_len(skb);
+		rtnl_kfree_skbs(skb, skb);
+		drop_count++;
+	}
+	qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
+
+	sch_tree_unlock(sch);
+	return err;
+}
+
+static void fq_destroy(struct Qdisc *sch)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+
+	fq_reset(sch);
+	fq_free(q->fq_root);
+	qdisc_watchdog_cancel(&q->watchdog);
+}
+
+static int fq_init(struct Qdisc *sch, struct nlattr *opt,
+		   struct netlink_ext_ack *extack)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	int err;
+
+	sch->limit		= 10000;
+	q->flow_plimit		= 100;
+	q->quantum		= 2 * psched_mtu(qdisc_dev(sch));
+	q->initial_quantum	= 10 * psched_mtu(qdisc_dev(sch));
+	q->flow_refill_delay	= msecs_to_jiffies(40);
+	q->flow_max_rate	= ~0U;
+	q->time_next_delayed_flow = ~0ULL;
+	q->rate_enable		= 1;
+	q->new_flows.first	= NULL;
+	q->old_flows.first	= NULL;
+	q->delayed		= RB_ROOT;
+	q->fq_root		= NULL;
+	q->fq_trees_log		= ilog2(1024);
+	q->orphan_mask		= 1024 - 1;
+	q->low_rate_threshold	= 550000 / 8;
+	qdisc_watchdog_init(&q->watchdog, sch);
+
+	if (opt)
+		err = fq_change(sch, opt, extack);
+	else
+		err = fq_resize(sch, q->fq_trees_log);
+
+	return err;
+}
+
+static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct nlattr *opts;
+
+	opts = nla_nest_start(skb, TCA_OPTIONS);
+	if (opts == NULL)
+		goto nla_put_failure;
+
+	/* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
+
+	if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
+	    nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
+	    nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
+	    nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
+	    nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
+	    nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) ||
+	    nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
+			jiffies_to_usecs(q->flow_refill_delay)) ||
+	    nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
+	    nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
+			q->low_rate_threshold) ||
+	    nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
+		goto nla_put_failure;
+
+	return nla_nest_end(skb, opts);
+
+nla_put_failure:
+	return -1;
+}
+
+static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+	struct fq_sched_data *q = qdisc_priv(sch);
+	struct tc_fq_qd_stats st;
+
+	sch_tree_lock(sch);
+
+	st.gc_flows		  = q->stat_gc_flows;
+	st.highprio_packets	  = q->stat_internal_packets;
+	st.tcp_retrans		  = q->stat_tcp_retrans;
+	st.throttled		  = q->stat_throttled;
+	st.flows_plimit		  = q->stat_flows_plimit;
+	st.pkts_too_long	  = q->stat_pkts_too_long;
+	st.allocation_errors	  = q->stat_allocation_errors;
+	st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
+	st.flows		  = q->flows;
+	st.inactive_flows	  = q->inactive_flows;
+	st.throttled_flows	  = q->throttled_flows;
+	st.unthrottle_latency_ns  = min_t(unsigned long,
+					  q->unthrottle_latency_ns, ~0U);
+	sch_tree_unlock(sch);
+
+	return gnet_stats_copy_app(d, &st, sizeof(st));
+}
+
+static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
+	.id		=	"fq",
+	.priv_size	=	sizeof(struct fq_sched_data),
+
+	.enqueue	=	fq_enqueue,
+	.dequeue	=	fq_dequeue,
+	.peek		=	qdisc_peek_dequeued,
+	.init		=	fq_init,
+	.reset		=	fq_reset,
+	.destroy	=	fq_destroy,
+	.change		=	fq_change,
+	.dump		=	fq_dump,
+	.dump_stats	=	fq_dump_stats,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init fq_module_init(void)
+{
+	int ret;
+
+	fq_flow_cachep = kmem_cache_create("fq_flow_cache",
+					   sizeof(struct fq_flow),
+					   0, 0, NULL);
+	if (!fq_flow_cachep)
+		return -ENOMEM;
+
+	ret = register_qdisc(&fq_qdisc_ops);
+	if (ret)
+		kmem_cache_destroy(fq_flow_cachep);
+	return ret;
+}
+
+static void __exit fq_module_exit(void)
+{
+	unregister_qdisc(&fq_qdisc_ops);
+	kmem_cache_destroy(fq_flow_cachep);
+}
+
+module_init(fq_module_init)
+module_exit(fq_module_exit)
+MODULE_AUTHOR("Eric Dumazet");
+MODULE_LICENSE("GPL");