4 files changed, 533 insertions, 0 deletions

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 5d921fa91a5..e3f133adba7 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -500,4 +500,20 @@ struct tc_netem_corrupt
 
 #define NETEM_DIST_SCALE	8192
 
+/* DRR */
+
+enum
+{
+	TCA_DRR_UNSPEC,
+	TCA_DRR_QUANTUM,
+	__TCA_DRR_MAX
+};
+
+#define TCA_DRR_MAX	(__TCA_DRR_MAX - 1)
+
+struct tc_drr_stats
+{
+	u32	deficit;
+};
+
 #endif
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 36543b6fcef..4f7ef0db302 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -194,6 +194,17 @@ config NET_SCH_NETEM
 
 	  If unsure, say N.
 
+config NET_SCH_DRR
+	tristate "Deficit Round Robin scheduler (DRR)"
+	help
+	  Say Y here if you want to use the Deficit Round Robin (DRR) packet
+	  scheduling algorithm.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called sch_drr.
+
+	  If unsure, say N.
+
 config NET_SCH_INGRESS
 	tristate "Ingress Qdisc"
 	depends on NET_CLS_ACT
diff --git a/net/sched/Makefile b/net/sched/Makefile
index 70b35f8708c..54d950cd4b8 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_NET_SCH_PRIO)	+= sch_prio.o
 obj-$(CONFIG_NET_SCH_MULTIQ)	+= sch_multiq.o
 obj-$(CONFIG_NET_SCH_ATM)	+= sch_atm.o
 obj-$(CONFIG_NET_SCH_NETEM)	+= sch_netem.o
+obj-$(CONFIG_NET_SCH_DRR)	+= sch_drr.o
 obj-$(CONFIG_NET_CLS_U32)	+= cls_u32.o
 obj-$(CONFIG_NET_CLS_ROUTE4)	+= cls_route.o
 obj-$(CONFIG_NET_CLS_FW)	+= cls_fw.o
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
new file mode 100644
index 00000000000..e71a5de23e2
--- /dev/null
+++ b/net/sched/sch_drr.c
@@ -0,0 +1,505 @@
+/*
+ * net/sched/sch_drr.c         Deficit Round Robin scheduler
+ *
+ * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/pkt_sched.h>
+#include <net/sch_generic.h>
+#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
+
+struct drr_class {
+	struct Qdisc_class_common	common;
+	unsigned int			refcnt;
+	unsigned int			filter_cnt;
+
+	struct gnet_stats_basic		bstats;
+	struct gnet_stats_queue		qstats;
+	struct gnet_stats_rate_est	rate_est;
+	struct list_head		alist;
+	struct Qdisc			*qdisc;
+
+	u32				quantum;
+	u32				deficit;
+};
+
+struct drr_sched {
+	struct list_head		active;
+	struct tcf_proto		*filter_list;
+	struct Qdisc_class_hash		clhash;
+};
+
+static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct Qdisc_class_common *clc;
+
+	clc = qdisc_class_find(&q->clhash, classid);
+	if (clc == NULL)
+		return NULL;
+	return container_of(clc, struct drr_class, common);
+}
+
+static void drr_purge_queue(struct drr_class *cl)
+{
+	unsigned int len = cl->qdisc->q.qlen;
+
+	qdisc_reset(cl->qdisc);
+	qdisc_tree_decrease_qlen(cl->qdisc, len);
+}
+
+static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
+	[TCA_DRR_QUANTUM]	= { .type = NLA_U32 },
+};
+
+static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
+			    struct nlattr **tca, unsigned long *arg)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl = (struct drr_class *)*arg;
+	struct nlattr *tb[TCA_DRR_MAX + 1];
+	u32 quantum;
+	int err;
+
+	err = nla_parse_nested(tb, TCA_DRR_MAX, tca[TCA_OPTIONS], drr_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_DRR_QUANTUM]) {
+		quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
+		if (quantum == 0)
+			return -EINVAL;
+	} else
+		quantum = psched_mtu(qdisc_dev(sch));
+
+	if (cl != NULL) {
+		sch_tree_lock(sch);
+		if (tb[TCA_DRR_QUANTUM])
+			cl->quantum = quantum;
+		sch_tree_unlock(sch);
+
+		if (tca[TCA_RATE])
+			gen_replace_estimator(&cl->bstats, &cl->rate_est,
+					      qdisc_root_sleeping_lock(sch),
+					      tca[TCA_RATE]);
+		return 0;
+	}
+
+	cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
+	if (cl == NULL)
+		return -ENOBUFS;
+
+	cl->refcnt	   = 1;
+	cl->common.classid = classid;
+	cl->quantum	   = quantum;
+	cl->qdisc	   = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
+					       &pfifo_qdisc_ops, classid);
+	if (cl->qdisc == NULL)
+		cl->qdisc = &noop_qdisc;
+
+	if (tca[TCA_RATE])
+		gen_replace_estimator(&cl->bstats, &cl->rate_est,
+				      qdisc_root_sleeping_lock(sch),
+				      tca[TCA_RATE]);
+
+	sch_tree_lock(sch);
+	qdisc_class_hash_insert(&q->clhash, &cl->common);
+	sch_tree_unlock(sch);
+
+	qdisc_class_hash_grow(sch, &q->clhash);
+
+	*arg = (unsigned long)cl;
+	return 0;
+}
+
+static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
+{
+	gen_kill_estimator(&cl->bstats, &cl->rate_est);
+	qdisc_destroy(cl->qdisc);
+	kfree(cl);
+}
+
+static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	if (cl->filter_cnt > 0)
+		return -EBUSY;
+
+	sch_tree_lock(sch);
+
+	drr_purge_queue(cl);
+	qdisc_class_hash_remove(&q->clhash, &cl->common);
+
+	if (--cl->refcnt == 0)
+		drr_destroy_class(sch, cl);
+
+	sch_tree_unlock(sch);
+	return 0;
+}
+
+static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
+{
+	struct drr_class *cl = drr_find_class(sch, classid);
+
+	if (cl != NULL)
+		cl->refcnt++;
+
+	return (unsigned long)cl;
+}
+
+static void drr_put_class(struct Qdisc *sch, unsigned long arg)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	if (--cl->refcnt == 0)
+		drr_destroy_class(sch, cl);
+}
+
+static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+
+	if (cl)
+		return NULL;
+
+	return &q->filter_list;
+}
+
+static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
+				  u32 classid)
+{
+	struct drr_class *cl = drr_find_class(sch, classid);
+
+	if (cl != NULL)
+		cl->filter_cnt++;
+
+	return (unsigned long)cl;
+}
+
+static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	cl->filter_cnt--;
+}
+
+static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
+			   struct Qdisc *new, struct Qdisc **old)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	if (new == NULL) {
+		new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
+					&pfifo_qdisc_ops, cl->common.classid);
+		if (new == NULL)
+			new = &noop_qdisc;
+	}
+
+	sch_tree_lock(sch);
+	drr_purge_queue(cl);
+	*old = xchg(&cl->qdisc, new);
+	sch_tree_unlock(sch);
+	return 0;
+}
+
+static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	return cl->qdisc;
+}
+
+static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+
+	if (cl->qdisc->q.qlen == 0)
+		list_del(&cl->alist);
+}
+
+static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
+			  struct sk_buff *skb, struct tcmsg *tcm)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+	struct nlattr *nest;
+
+	tcm->tcm_parent	= TC_H_ROOT;
+	tcm->tcm_handle	= cl->common.classid;
+	tcm->tcm_info	= cl->qdisc->handle;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+	NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
+	return nla_nest_end(skb, nest);
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
+static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
+				struct gnet_dump *d)
+{
+	struct drr_class *cl = (struct drr_class *)arg;
+	struct tc_drr_stats xstats;
+
+	memset(&xstats, 0, sizeof(xstats));
+	if (cl->qdisc->q.qlen)
+		xstats.deficit = cl->deficit;
+
+	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
+	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
+	    gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
+		return -1;
+
+	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
+}
+
+static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	struct hlist_node *n;
+	unsigned int i;
+
+	if (arg->stop)
+		return;
+
+	for (i = 0; i < q->clhash.hashsize; i++) {
+		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
+			if (arg->count < arg->skip) {
+				arg->count++;
+				continue;
+			}
+			if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
+				arg->stop = 1;
+				return;
+			}
+			arg->count++;
+		}
+	}
+}
+
+static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
+				      int *qerr)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	struct tcf_result res;
+	int result;
+
+	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
+		cl = drr_find_class(sch, skb->priority);
+		if (cl != NULL)
+			return cl;
+	}
+
+	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
+	result = tc_classify(skb, q->filter_list, &res);
+	if (result >= 0) {
+#ifdef CONFIG_NET_CLS_ACT
+		switch (result) {
+		case TC_ACT_QUEUED:
+		case TC_ACT_STOLEN:
+			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
+		case TC_ACT_SHOT:
+			return NULL;
+		}
+#endif
+		cl = (struct drr_class *)res.class;
+		if (cl == NULL)
+			cl = drr_find_class(sch, res.classid);
+		return cl;
+	}
+	return NULL;
+}
+
+static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	unsigned int len;
+	int err;
+
+	cl = drr_classify(skb, sch, &err);
+	if (cl == NULL) {
+		if (err & __NET_XMIT_BYPASS)
+			sch->qstats.drops++;
+		kfree_skb(skb);
+		return err;
+	}
+
+	len = qdisc_pkt_len(skb);
+	err = qdisc_enqueue(skb, cl->qdisc);
+	if (unlikely(err != NET_XMIT_SUCCESS)) {
+		if (net_xmit_drop_count(err)) {
+			cl->qstats.drops++;
+			sch->qstats.drops++;
+		}
+		return err;
+	}
+
+	if (cl->qdisc->q.qlen == 1) {
+		list_add_tail(&cl->alist, &q->active);
+		cl->deficit = cl->quantum;
+	}
+
+	cl->bstats.packets++;
+	cl->bstats.bytes += len;
+	sch->bstats.packets++;
+	sch->bstats.bytes += len;
+
+	sch->q.qlen++;
+	return err;
+}
+
+static struct sk_buff *drr_dequeue(struct Qdisc *sch)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	struct sk_buff *skb;
+	unsigned int len;
+
+	while (!list_empty(&q->active)) {
+		cl = list_first_entry(&q->active, struct drr_class, alist);
+		skb = cl->qdisc->ops->peek(cl->qdisc);
+		if (skb == NULL)
+			goto skip;
+
+		len = qdisc_pkt_len(skb);
+		if (len <= cl->deficit) {
+			cl->deficit -= len;
+			skb = qdisc_dequeue_peeked(cl->qdisc);
+			if (cl->qdisc->q.qlen == 0)
+				list_del(&cl->alist);
+			sch->q.qlen--;
+			return skb;
+		}
+
+		cl->deficit += cl->quantum;
+skip:
+		list_move_tail(&cl->alist, &q->active);
+	}
+	return NULL;
+}
+
+static unsigned int drr_drop(struct Qdisc *sch)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	unsigned int len;
+
+	list_for_each_entry(cl, &q->active, alist) {
+		if (cl->qdisc->ops->drop) {
+			len = cl->qdisc->ops->drop(cl->qdisc);
+			if (len > 0) {
+				if (cl->qdisc->q.qlen == 0)
+					list_del(&cl->alist);
+				return len;
+			}
+		}
+	}
+	return 0;
+}
+
+static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	int err;
+
+	err = qdisc_class_hash_init(&q->clhash);
+	if (err < 0)
+		return err;
+	INIT_LIST_HEAD(&q->active);
+	return 0;
+}
+
+static void drr_reset_qdisc(struct Qdisc *sch)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	struct hlist_node *n;
+	unsigned int i;
+
+	for (i = 0; i < q->clhash.hashsize; i++) {
+		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
+			if (cl->qdisc->q.qlen)
+				list_del(&cl->alist);
+			qdisc_reset(cl->qdisc);
+		}
+	}
+	sch->q.qlen = 0;
+}
+
+static void drr_destroy_qdisc(struct Qdisc *sch)
+{
+	struct drr_sched *q = qdisc_priv(sch);
+	struct drr_class *cl;
+	struct hlist_node *n, *next;
+	unsigned int i;
+
+	tcf_destroy_chain(&q->filter_list);
+
+	for (i = 0; i < q->clhash.hashsize; i++) {
+		hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
+					  common.hnode)
+			drr_destroy_class(sch, cl);
+	}
+	qdisc_class_hash_destroy(&q->clhash);
+}
+
+static const struct Qdisc_class_ops drr_class_ops = {
+	.change		= drr_change_class,
+	.delete		= drr_delete_class,
+	.get		= drr_get_class,
+	.put		= drr_put_class,
+	.tcf_chain	= drr_tcf_chain,
+	.bind_tcf	= drr_bind_tcf,
+	.unbind_tcf	= drr_unbind_tcf,
+	.graft		= drr_graft_class,
+	.leaf		= drr_class_leaf,
+	.qlen_notify	= drr_qlen_notify,
+	.dump		= drr_dump_class,
+	.dump_stats	= drr_dump_class_stats,
+	.walk		= drr_walk,
+};
+
+static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
+	.cl_ops		= &drr_class_ops,
+	.id		= "drr",
+	.priv_size	= sizeof(struct drr_sched),
+	.enqueue	= drr_enqueue,
+	.dequeue	= drr_dequeue,
+	.peek		= qdisc_peek_dequeued,
+	.drop		= drr_drop,
+	.init		= drr_init_qdisc,
+	.reset		= drr_reset_qdisc,
+	.destroy	= drr_destroy_qdisc,
+	.owner		= THIS_MODULE,
+};
+
+static int __init drr_init(void)
+{
+	return register_qdisc(&drr_qdisc_ops);
+}
+
+static void __exit drr_exit(void)
+{
+	unregister_qdisc(&drr_qdisc_ops);
+}
+
+module_init(drr_init);
+module_exit(drr_exit);
+MODULE_LICENSE("GPL");