Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 939 insertions, 0 deletions

diff --git a/kernel/net/sched/sch_sfq.c b/kernel/net/sched/sch_sfq.c
new file mode 100644
index 000000000..b877140be
--- /dev/null
+++ b/kernel/net/sched/sch_sfq.c
@@ -0,0 +1,939 @@
+/*
+ * net/sched/sch_sfq.c	Stochastic Fairness Queueing discipline.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+#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/jhash.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/flow_keys.h>
+#include <net/red.h>
+
+
+/*	Stochastic Fairness Queuing algorithm.
+	=======================================
+
+	Source:
+	Paul E. McKenney "Stochastic Fairness Queuing",
+	IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
+
+	Paul E. McKenney "Stochastic Fairness Queuing",
+	"Interworking: Research and Experience", v.2, 1991, p.113-131.
+
+
+	See also:
+	M. Shreedhar and George Varghese "Efficient Fair
+	Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
+
+
+	This is not the thing that is usually called (W)FQ nowadays.
+	It does not use any timestamp mechanism, but instead
+	processes queues in round-robin order.
+
+	ADVANTAGE:
+
+	- It is very cheap. Both CPU and memory requirements are minimal.
+
+	DRAWBACKS:
+
+	- "Stochastic" -> It is not 100% fair.
+	When hash collisions occur, several flows are considered as one.
+
+	- "Round-robin" -> It introduces larger delays than virtual clock
+	based schemes, and should not be used for isolating interactive
+	traffic	from non-interactive. It means, that this scheduler
+	should be used as leaf of CBQ or P3, which put interactive traffic
+	to higher priority band.
+
+	We still need true WFQ for top level CSZ, but using WFQ
+	for the best effort traffic is absolutely pointless:
+	SFQ is superior for this purpose.
+
+	IMPLEMENTATION:
+	This implementation limits :
+	- maximal queue length per flow to 127 packets.
+	- max mtu to 2^18-1;
+	- max 65408 flows,
+	- number of hash buckets to 65536.
+
+	It is easy to increase these values, but not in flight.  */
+
+#define SFQ_MAX_DEPTH		127 /* max number of packets per flow */
+#define SFQ_DEFAULT_FLOWS	128
+#define SFQ_MAX_FLOWS		(0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
+#define SFQ_EMPTY_SLOT		0xffff
+#define SFQ_DEFAULT_HASH_DIVISOR 1024
+
+/* We use 16 bits to store allot, and want to handle packets up to 64K
+ * Scale allot by 8 (1<<3) so that no overflow occurs.
+ */
+#define SFQ_ALLOT_SHIFT		3
+#define SFQ_ALLOT_SIZE(X)	DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
+
+/* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
+typedef u16 sfq_index;
+
+/*
+ * We dont use pointers to save space.
+ * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
+ * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
+ * are 'pointers' to dep[] array
+ */
+struct sfq_head {
+	sfq_index	next;
+	sfq_index	prev;
+};
+
+struct sfq_slot {
+	struct sk_buff	*skblist_next;
+	struct sk_buff	*skblist_prev;
+	sfq_index	qlen; /* number of skbs in skblist */
+	sfq_index	next; /* next slot in sfq RR chain */
+	struct sfq_head dep; /* anchor in dep[] chains */
+	unsigned short	hash; /* hash value (index in ht[]) */
+	short		allot; /* credit for this slot */
+
+	unsigned int    backlog;
+	struct red_vars vars;
+};
+
+struct sfq_sched_data {
+/* frequently used fields */
+	int		limit;		/* limit of total number of packets in this qdisc */
+	unsigned int	divisor;	/* number of slots in hash table */
+	u8		headdrop;
+	u8		maxdepth;	/* limit of packets per flow */
+
+	u32		perturbation;
+	u8		cur_depth;	/* depth of longest slot */
+	u8		flags;
+	unsigned short  scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
+	struct tcf_proto __rcu *filter_list;
+	sfq_index	*ht;		/* Hash table ('divisor' slots) */
+	struct sfq_slot	*slots;		/* Flows table ('maxflows' entries) */
+
+	struct red_parms *red_parms;
+	struct tc_sfqred_stats stats;
+	struct sfq_slot *tail;		/* current slot in round */
+
+	struct sfq_head	dep[SFQ_MAX_DEPTH + 1];
+					/* Linked lists of slots, indexed by depth
+					 * dep[0] : list of unused flows
+					 * dep[1] : list of flows with 1 packet
+					 * dep[X] : list of flows with X packets
+					 */
+
+	unsigned int	maxflows;	/* number of flows in flows array */
+	int		perturb_period;
+	unsigned int	quantum;	/* Allotment per round: MUST BE >= MTU */
+	struct timer_list perturb_timer;
+};
+
+/*
+ * sfq_head are either in a sfq_slot or in dep[] array
+ */
+static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
+{
+	if (val < SFQ_MAX_FLOWS)
+		return &q->slots[val].dep;
+	return &q->dep[val - SFQ_MAX_FLOWS];
+}
+
+/*
+ * In order to be able to quickly rehash our queue when timer changes
+ * q->perturbation, we store flow_keys in skb->cb[]
+ */
+struct sfq_skb_cb {
+       struct flow_keys        keys;
+};
+
+static inline struct sfq_skb_cb *sfq_skb_cb(const struct sk_buff *skb)
+{
+	qdisc_cb_private_validate(skb, sizeof(struct sfq_skb_cb));
+	return (struct sfq_skb_cb *)qdisc_skb_cb(skb)->data;
+}
+
+static unsigned int sfq_hash(const struct sfq_sched_data *q,
+			     const struct sk_buff *skb)
+{
+	const struct flow_keys *keys = &sfq_skb_cb(skb)->keys;
+	unsigned int hash;
+
+	hash = jhash_3words((__force u32)keys->dst,
+			    (__force u32)keys->src ^ keys->ip_proto,
+			    (__force u32)keys->ports, q->perturbation);
+	return hash & (q->divisor - 1);
+}
+
+static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
+				 int *qerr)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	struct tcf_result res;
+	struct tcf_proto *fl;
+	int result;
+
+	if (TC_H_MAJ(skb->priority) == sch->handle &&
+	    TC_H_MIN(skb->priority) > 0 &&
+	    TC_H_MIN(skb->priority) <= q->divisor)
+		return TC_H_MIN(skb->priority);
+
+	fl = rcu_dereference_bh(q->filter_list);
+	if (!fl) {
+		skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys);
+		return sfq_hash(q, skb) + 1;
+	}
+
+	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
+	result = tc_classify(skb, fl, &res);
+	if (result >= 0) {
+#ifdef CONFIG_NET_CLS_ACT
+		switch (result) {
+		case TC_ACT_STOLEN:
+		case TC_ACT_QUEUED:
+			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
+		case TC_ACT_SHOT:
+			return 0;
+		}
+#endif
+		if (TC_H_MIN(res.classid) <= q->divisor)
+			return TC_H_MIN(res.classid);
+	}
+	return 0;
+}
+
+/*
+ * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
+ */
+static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
+{
+	sfq_index p, n;
+	struct sfq_slot *slot = &q->slots[x];
+	int qlen = slot->qlen;
+
+	p = qlen + SFQ_MAX_FLOWS;
+	n = q->dep[qlen].next;
+
+	slot->dep.next = n;
+	slot->dep.prev = p;
+
+	q->dep[qlen].next = x;		/* sfq_dep_head(q, p)->next = x */
+	sfq_dep_head(q, n)->prev = x;
+}
+
+#define sfq_unlink(q, x, n, p)			\
+	do {					\
+		n = q->slots[x].dep.next;	\
+		p = q->slots[x].dep.prev;	\
+		sfq_dep_head(q, p)->next = n;	\
+		sfq_dep_head(q, n)->prev = p;	\
+	} while (0)
+
+
+static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
+{
+	sfq_index p, n;
+	int d;
+
+	sfq_unlink(q, x, n, p);
+
+	d = q->slots[x].qlen--;
+	if (n == p && q->cur_depth == d)
+		q->cur_depth--;
+	sfq_link(q, x);
+}
+
+static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
+{
+	sfq_index p, n;
+	int d;
+
+	sfq_unlink(q, x, n, p);
+
+	d = ++q->slots[x].qlen;
+	if (q->cur_depth < d)
+		q->cur_depth = d;
+	sfq_link(q, x);
+}
+
+/* helper functions : might be changed when/if skb use a standard list_head */
+
+/* remove one skb from tail of slot queue */
+static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
+{
+	struct sk_buff *skb = slot->skblist_prev;
+
+	slot->skblist_prev = skb->prev;
+	skb->prev->next = (struct sk_buff *)slot;
+	skb->next = skb->prev = NULL;
+	return skb;
+}
+
+/* remove one skb from head of slot queue */
+static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
+{
+	struct sk_buff *skb = slot->skblist_next;
+
+	slot->skblist_next = skb->next;
+	skb->next->prev = (struct sk_buff *)slot;
+	skb->next = skb->prev = NULL;
+	return skb;
+}
+
+static inline void slot_queue_init(struct sfq_slot *slot)
+{
+	memset(slot, 0, sizeof(*slot));
+	slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
+}
+
+/* add skb to slot queue (tail add) */
+static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
+{
+	skb->prev = slot->skblist_prev;
+	skb->next = (struct sk_buff *)slot;
+	slot->skblist_prev->next = skb;
+	slot->skblist_prev = skb;
+}
+
+static unsigned int sfq_drop(struct Qdisc *sch)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	sfq_index x, d = q->cur_depth;
+	struct sk_buff *skb;
+	unsigned int len;
+	struct sfq_slot *slot;
+
+	/* Queue is full! Find the longest slot and drop tail packet from it */
+	if (d > 1) {
+		x = q->dep[d].next;
+		slot = &q->slots[x];
+drop:
+		skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
+		len = qdisc_pkt_len(skb);
+		slot->backlog -= len;
+		sfq_dec(q, x);
+		kfree_skb(skb);
+		sch->q.qlen--;
+		qdisc_qstats_drop(sch);
+		qdisc_qstats_backlog_dec(sch, skb);
+		return len;
+	}
+
+	if (d == 1) {
+		/* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
+		x = q->tail->next;
+		slot = &q->slots[x];
+		q->tail->next = slot->next;
+		q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+		goto drop;
+	}
+
+	return 0;
+}
+
+/* Is ECN parameter configured */
+static int sfq_prob_mark(const struct sfq_sched_data *q)
+{
+	return q->flags & TC_RED_ECN;
+}
+
+/* Should packets over max threshold just be marked */
+static int sfq_hard_mark(const struct sfq_sched_data *q)
+{
+	return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
+}
+
+static int sfq_headdrop(const struct sfq_sched_data *q)
+{
+	return q->headdrop;
+}
+
+static int
+sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	unsigned int hash;
+	sfq_index x, qlen;
+	struct sfq_slot *slot;
+	int uninitialized_var(ret);
+	struct sk_buff *head;
+	int delta;
+
+	hash = sfq_classify(skb, sch, &ret);
+	if (hash == 0) {
+		if (ret & __NET_XMIT_BYPASS)
+			qdisc_qstats_drop(sch);
+		kfree_skb(skb);
+		return ret;
+	}
+	hash--;
+
+	x = q->ht[hash];
+	slot = &q->slots[x];
+	if (x == SFQ_EMPTY_SLOT) {
+		x = q->dep[0].next; /* get a free slot */
+		if (x >= SFQ_MAX_FLOWS)
+			return qdisc_drop(skb, sch);
+		q->ht[hash] = x;
+		slot = &q->slots[x];
+		slot->hash = hash;
+		slot->backlog = 0; /* should already be 0 anyway... */
+		red_set_vars(&slot->vars);
+		goto enqueue;
+	}
+	if (q->red_parms) {
+		slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
+							&slot->vars,
+							slot->backlog);
+		switch (red_action(q->red_parms,
+				   &slot->vars,
+				   slot->vars.qavg)) {
+		case RED_DONT_MARK:
+			break;
+
+		case RED_PROB_MARK:
+			qdisc_qstats_overlimit(sch);
+			if (sfq_prob_mark(q)) {
+				/* We know we have at least one packet in queue */
+				if (sfq_headdrop(q) &&
+				    INET_ECN_set_ce(slot->skblist_next)) {
+					q->stats.prob_mark_head++;
+					break;
+				}
+				if (INET_ECN_set_ce(skb)) {
+					q->stats.prob_mark++;
+					break;
+				}
+			}
+			q->stats.prob_drop++;
+			goto congestion_drop;
+
+		case RED_HARD_MARK:
+			qdisc_qstats_overlimit(sch);
+			if (sfq_hard_mark(q)) {
+				/* We know we have at least one packet in queue */
+				if (sfq_headdrop(q) &&
+				    INET_ECN_set_ce(slot->skblist_next)) {
+					q->stats.forced_mark_head++;
+					break;
+				}
+				if (INET_ECN_set_ce(skb)) {
+					q->stats.forced_mark++;
+					break;
+				}
+			}
+			q->stats.forced_drop++;
+			goto congestion_drop;
+		}
+	}
+
+	if (slot->qlen >= q->maxdepth) {
+congestion_drop:
+		if (!sfq_headdrop(q))
+			return qdisc_drop(skb, sch);
+
+		/* We know we have at least one packet in queue */
+		head = slot_dequeue_head(slot);
+		delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
+		sch->qstats.backlog -= delta;
+		slot->backlog -= delta;
+		qdisc_drop(head, sch);
+
+		slot_queue_add(slot, skb);
+		return NET_XMIT_CN;
+	}
+
+enqueue:
+	qdisc_qstats_backlog_inc(sch, skb);
+	slot->backlog += qdisc_pkt_len(skb);
+	slot_queue_add(slot, skb);
+	sfq_inc(q, x);
+	if (slot->qlen == 1) {		/* The flow is new */
+		if (q->tail == NULL) {	/* It is the first flow */
+			slot->next = x;
+		} else {
+			slot->next = q->tail->next;
+			q->tail->next = x;
+		}
+		/* We put this flow at the end of our flow list.
+		 * This might sound unfair for a new flow to wait after old ones,
+		 * but we could endup servicing new flows only, and freeze old ones.
+		 */
+		q->tail = slot;
+		/* We could use a bigger initial quantum for new flows */
+		slot->allot = q->scaled_quantum;
+	}
+	if (++sch->q.qlen <= q->limit)
+		return NET_XMIT_SUCCESS;
+
+	qlen = slot->qlen;
+	sfq_drop(sch);
+	/* Return Congestion Notification only if we dropped a packet
+	 * from this flow.
+	 */
+	if (qlen != slot->qlen)
+		return NET_XMIT_CN;
+
+	/* As we dropped a packet, better let upper stack know this */
+	qdisc_tree_decrease_qlen(sch, 1);
+	return NET_XMIT_SUCCESS;
+}
+
+static struct sk_buff *
+sfq_dequeue(struct Qdisc *sch)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+	sfq_index a, next_a;
+	struct sfq_slot *slot;
+
+	/* No active slots */
+	if (q->tail == NULL)
+		return NULL;
+
+next_slot:
+	a = q->tail->next;
+	slot = &q->slots[a];
+	if (slot->allot <= 0) {
+		q->tail = slot;
+		slot->allot += q->scaled_quantum;
+		goto next_slot;
+	}
+	skb = slot_dequeue_head(slot);
+	sfq_dec(q, a);
+	qdisc_bstats_update(sch, skb);
+	sch->q.qlen--;
+	qdisc_qstats_backlog_dec(sch, skb);
+	slot->backlog -= qdisc_pkt_len(skb);
+	/* Is the slot empty? */
+	if (slot->qlen == 0) {
+		q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+		next_a = slot->next;
+		if (a == next_a) {
+			q->tail = NULL; /* no more active slots */
+			return skb;
+		}
+		q->tail->next = next_a;
+	} else {
+		slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
+	}
+	return skb;
+}
+
+static void
+sfq_reset(struct Qdisc *sch)
+{
+	struct sk_buff *skb;
+
+	while ((skb = sfq_dequeue(sch)) != NULL)
+		kfree_skb(skb);
+}
+
+/*
+ * When q->perturbation is changed, we rehash all queued skbs
+ * to avoid OOO (Out Of Order) effects.
+ * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
+ * counters.
+ */
+static void sfq_rehash(struct Qdisc *sch)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+	int i;
+	struct sfq_slot *slot;
+	struct sk_buff_head list;
+	int dropped = 0;
+
+	__skb_queue_head_init(&list);
+
+	for (i = 0; i < q->maxflows; i++) {
+		slot = &q->slots[i];
+		if (!slot->qlen)
+			continue;
+		while (slot->qlen) {
+			skb = slot_dequeue_head(slot);
+			sfq_dec(q, i);
+			__skb_queue_tail(&list, skb);
+		}
+		slot->backlog = 0;
+		red_set_vars(&slot->vars);
+		q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+	}
+	q->tail = NULL;
+
+	while ((skb = __skb_dequeue(&list)) != NULL) {
+		unsigned int hash = sfq_hash(q, skb);
+		sfq_index x = q->ht[hash];
+
+		slot = &q->slots[x];
+		if (x == SFQ_EMPTY_SLOT) {
+			x = q->dep[0].next; /* get a free slot */
+			if (x >= SFQ_MAX_FLOWS) {
+drop:
+				qdisc_qstats_backlog_dec(sch, skb);
+				kfree_skb(skb);
+				dropped++;
+				continue;
+			}
+			q->ht[hash] = x;
+			slot = &q->slots[x];
+			slot->hash = hash;
+		}
+		if (slot->qlen >= q->maxdepth)
+			goto drop;
+		slot_queue_add(slot, skb);
+		if (q->red_parms)
+			slot->vars.qavg = red_calc_qavg(q->red_parms,
+							&slot->vars,
+							slot->backlog);
+		slot->backlog += qdisc_pkt_len(skb);
+		sfq_inc(q, x);
+		if (slot->qlen == 1) {		/* The flow is new */
+			if (q->tail == NULL) {	/* It is the first flow */
+				slot->next = x;
+			} else {
+				slot->next = q->tail->next;
+				q->tail->next = x;
+			}
+			q->tail = slot;
+			slot->allot = q->scaled_quantum;
+		}
+	}
+	sch->q.qlen -= dropped;
+	qdisc_tree_decrease_qlen(sch, dropped);
+}
+
+static void sfq_perturbation(unsigned long arg)
+{
+	struct Qdisc *sch = (struct Qdisc *)arg;
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
+
+	spin_lock(root_lock);
+	q->perturbation = prandom_u32();
+	if (!q->filter_list && q->tail)
+		sfq_rehash(sch);
+	spin_unlock(root_lock);
+
+	if (q->perturb_period)
+		mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
+}
+
+static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	struct tc_sfq_qopt *ctl = nla_data(opt);
+	struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
+	unsigned int qlen;
+	struct red_parms *p = NULL;
+
+	if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
+		return -EINVAL;
+	if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
+		ctl_v1 = nla_data(opt);
+	if (ctl->divisor &&
+	    (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
+		return -EINVAL;
+	if (ctl_v1 && ctl_v1->qth_min) {
+		p = kmalloc(sizeof(*p), GFP_KERNEL);
+		if (!p)
+			return -ENOMEM;
+	}
+	sch_tree_lock(sch);
+	if (ctl->quantum) {
+		q->quantum = ctl->quantum;
+		q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
+	}
+	q->perturb_period = ctl->perturb_period * HZ;
+	if (ctl->flows)
+		q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
+	if (ctl->divisor) {
+		q->divisor = ctl->divisor;
+		q->maxflows = min_t(u32, q->maxflows, q->divisor);
+	}
+	if (ctl_v1) {
+		if (ctl_v1->depth)
+			q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
+		if (p) {
+			swap(q->red_parms, p);
+			red_set_parms(q->red_parms,
+				      ctl_v1->qth_min, ctl_v1->qth_max,
+				      ctl_v1->Wlog,
+				      ctl_v1->Plog, ctl_v1->Scell_log,
+				      NULL,
+				      ctl_v1->max_P);
+		}
+		q->flags = ctl_v1->flags;
+		q->headdrop = ctl_v1->headdrop;
+	}
+	if (ctl->limit) {
+		q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
+		q->maxflows = min_t(u32, q->maxflows, q->limit);
+	}
+
+	qlen = sch->q.qlen;
+	while (sch->q.qlen > q->limit)
+		sfq_drop(sch);
+	qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
+
+	del_timer(&q->perturb_timer);
+	if (q->perturb_period) {
+		mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
+		q->perturbation = prandom_u32();
+	}
+	sch_tree_unlock(sch);
+	kfree(p);
+	return 0;
+}
+
+static void *sfq_alloc(size_t sz)
+{
+	void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
+
+	if (!ptr)
+		ptr = vmalloc(sz);
+	return ptr;
+}
+
+static void sfq_free(void *addr)
+{
+	kvfree(addr);
+}
+
+static void sfq_destroy(struct Qdisc *sch)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+
+	tcf_destroy_chain(&q->filter_list);
+	q->perturb_period = 0;
+	del_timer_sync(&q->perturb_timer);
+	sfq_free(q->ht);
+	sfq_free(q->slots);
+	kfree(q->red_parms);
+}
+
+static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	int i;
+
+	q->perturb_timer.function = sfq_perturbation;
+	q->perturb_timer.data = (unsigned long)sch;
+	init_timer_deferrable(&q->perturb_timer);
+
+	for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
+		q->dep[i].next = i + SFQ_MAX_FLOWS;
+		q->dep[i].prev = i + SFQ_MAX_FLOWS;
+	}
+
+	q->limit = SFQ_MAX_DEPTH;
+	q->maxdepth = SFQ_MAX_DEPTH;
+	q->cur_depth = 0;
+	q->tail = NULL;
+	q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
+	q->maxflows = SFQ_DEFAULT_FLOWS;
+	q->quantum = psched_mtu(qdisc_dev(sch));
+	q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
+	q->perturb_period = 0;
+	q->perturbation = prandom_u32();
+
+	if (opt) {
+		int err = sfq_change(sch, opt);
+		if (err)
+			return err;
+	}
+
+	q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
+	q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
+	if (!q->ht || !q->slots) {
+		sfq_destroy(sch);
+		return -ENOMEM;
+	}
+	for (i = 0; i < q->divisor; i++)
+		q->ht[i] = SFQ_EMPTY_SLOT;
+
+	for (i = 0; i < q->maxflows; i++) {
+		slot_queue_init(&q->slots[i]);
+		sfq_link(q, i);
+	}
+	if (q->limit >= 1)
+		sch->flags |= TCQ_F_CAN_BYPASS;
+	else
+		sch->flags &= ~TCQ_F_CAN_BYPASS;
+	return 0;
+}
+
+static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tc_sfq_qopt_v1 opt;
+	struct red_parms *p = q->red_parms;
+
+	memset(&opt, 0, sizeof(opt));
+	opt.v0.quantum	= q->quantum;
+	opt.v0.perturb_period = q->perturb_period / HZ;
+	opt.v0.limit	= q->limit;
+	opt.v0.divisor	= q->divisor;
+	opt.v0.flows	= q->maxflows;
+	opt.depth	= q->maxdepth;
+	opt.headdrop	= q->headdrop;
+
+	if (p) {
+		opt.qth_min	= p->qth_min >> p->Wlog;
+		opt.qth_max	= p->qth_max >> p->Wlog;
+		opt.Wlog	= p->Wlog;
+		opt.Plog	= p->Plog;
+		opt.Scell_log	= p->Scell_log;
+		opt.max_P	= p->max_P;
+	}
+	memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
+	opt.flags	= q->flags;
+
+	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
+		goto nla_put_failure;
+
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
+{
+	return NULL;
+}
+
+static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
+{
+	return 0;
+}
+
+static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
+			      u32 classid)
+{
+	/* we cannot bypass queue discipline anymore */
+	sch->flags &= ~TCQ_F_CAN_BYPASS;
+	return 0;
+}
+
+static void sfq_put(struct Qdisc *q, unsigned long cl)
+{
+}
+
+static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch,
+					     unsigned long cl)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+
+	if (cl)
+		return NULL;
+	return &q->filter_list;
+}
+
+static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
+			  struct sk_buff *skb, struct tcmsg *tcm)
+{
+	tcm->tcm_handle |= TC_H_MIN(cl);
+	return 0;
+}
+
+static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
+				struct gnet_dump *d)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	sfq_index idx = q->ht[cl - 1];
+	struct gnet_stats_queue qs = { 0 };
+	struct tc_sfq_xstats xstats = { 0 };
+
+	if (idx != SFQ_EMPTY_SLOT) {
+		const struct sfq_slot *slot = &q->slots[idx];
+
+		xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
+		qs.qlen = slot->qlen;
+		qs.backlog = slot->backlog;
+	}
+	if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
+		return -1;
+	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
+}
+
+static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+	struct sfq_sched_data *q = qdisc_priv(sch);
+	unsigned int i;
+
+	if (arg->stop)
+		return;
+
+	for (i = 0; i < q->divisor; i++) {
+		if (q->ht[i] == SFQ_EMPTY_SLOT ||
+		    arg->count < arg->skip) {
+			arg->count++;
+			continue;
+		}
+		if (arg->fn(sch, i + 1, arg) < 0) {
+			arg->stop = 1;
+			break;
+		}
+		arg->count++;
+	}
+}
+
+static const struct Qdisc_class_ops sfq_class_ops = {
+	.leaf		=	sfq_leaf,
+	.get		=	sfq_get,
+	.put		=	sfq_put,
+	.tcf_chain	=	sfq_find_tcf,
+	.bind_tcf	=	sfq_bind,
+	.unbind_tcf	=	sfq_put,
+	.dump		=	sfq_dump_class,
+	.dump_stats	=	sfq_dump_class_stats,
+	.walk		=	sfq_walk,
+};
+
+static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
+	.cl_ops		=	&sfq_class_ops,
+	.id		=	"sfq",
+	.priv_size	=	sizeof(struct sfq_sched_data),
+	.enqueue	=	sfq_enqueue,
+	.dequeue	=	sfq_dequeue,
+	.peek		=	qdisc_peek_dequeued,
+	.drop		=	sfq_drop,
+	.init		=	sfq_init,
+	.reset		=	sfq_reset,
+	.destroy	=	sfq_destroy,
+	.change		=	NULL,
+	.dump		=	sfq_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init sfq_module_init(void)
+{
+	return register_qdisc(&sfq_qdisc_ops);
+}
+static void __exit sfq_module_exit(void)
+{
+	unregister_qdisc(&sfq_qdisc_ops);
+}
+module_init(sfq_module_init)
+module_exit(sfq_module_exit)
+MODULE_LICENSE("GPL");