3 files changed, 517 insertions, 0 deletions

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 36543b6fcef3..4f7ef0db302b 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 70b35f8708c3..54d950cd4b8d 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 000000000000..e71a5de23e23
--- /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");