File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
new file mode 100644
index 0000000..8c0508c
--- /dev/null
+++ b/net/sched/sch_red.c
@@ -0,0 +1,387 @@
+/*
+ * net/sched/sch_red.c Random Early Detection queue.
+ *
+ * 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>
+ *
+ * Changes:
+ * J Hadi Salim 980914: computation fixes
+ * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
+ * J Hadi Salim 980816: ECN support
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+#include <net/inet_ecn.h>
+#include <net/red.h>
+
+
+/* Parameters, settable by user:
+ -----------------------------
+
+ limit - bytes (must be > qth_max + burst)
+
+ Hard limit on queue length, should be chosen >qth_max
+ to allow packet bursts. This parameter does not
+ affect the algorithms behaviour and can be chosen
+ arbitrarily high (well, less than ram size)
+ Really, this limit will never be reached
+ if RED works correctly.
+ */
+
+struct red_sched_data {
+ u32 limit; /* HARD maximal queue length */
+ unsigned char flags;
+ struct timer_list adapt_timer;
+ struct red_parms parms;
+ struct red_vars vars;
+ struct red_stats stats;
+ struct Qdisc *qdisc;
+};
+
+static inline int red_use_ecn(struct red_sched_data *q)
+{
+ return q->flags & TC_RED_ECN;
+}
+
+static inline int red_use_harddrop(struct red_sched_data *q)
+{
+ return q->flags & TC_RED_HARDDROP;
+}
+
+static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+ int ret;
+
+ q->vars.qavg = red_calc_qavg(&q->parms,
+ &q->vars,
+ child->qstats.backlog);
+
+ if (red_is_idling(&q->vars))
+ red_end_of_idle_period(&q->vars);
+
+ switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
+ case RED_DONT_MARK:
+ break;
+
+ case RED_PROB_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
+ q->stats.prob_drop++;
+ goto congestion_drop;
+ }
+
+ q->stats.prob_mark++;
+ break;
+
+ case RED_HARD_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (red_use_harddrop(q) || !red_use_ecn(q) ||
+ !INET_ECN_set_ce(skb)) {
+ q->stats.forced_drop++;
+ goto congestion_drop;
+ }
+
+ q->stats.forced_mark++;
+ break;
+ }
+
+ ret = qdisc_enqueue(skb, child);
+ if (likely(ret == NET_XMIT_SUCCESS)) {
+ sch->q.qlen++;
+ } else if (net_xmit_drop_count(ret)) {
+ q->stats.pdrop++;
+ qdisc_qstats_drop(sch);
+ }
+ return ret;
+
+congestion_drop:
+ qdisc_drop(skb, sch);
+ return NET_XMIT_CN;
+}
+
+static struct sk_buff *red_dequeue(struct Qdisc *sch)
+{
+ struct sk_buff *skb;
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+
+ skb = child->dequeue(child);
+ if (skb) {
+ qdisc_bstats_update(sch, skb);
+ sch->q.qlen--;
+ } else {
+ if (!red_is_idling(&q->vars))
+ red_start_of_idle_period(&q->vars);
+ }
+ return skb;
+}
+
+static struct sk_buff *red_peek(struct Qdisc *sch)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+
+ return child->ops->peek(child);
+}
+
+static unsigned int red_drop(struct Qdisc *sch)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+ unsigned int len;
+
+ if (child->ops->drop && (len = child->ops->drop(child)) > 0) {
+ q->stats.other++;
+ qdisc_qstats_drop(sch);
+ sch->q.qlen--;
+ return len;
+ }
+
+ if (!red_is_idling(&q->vars))
+ red_start_of_idle_period(&q->vars);
+
+ return 0;
+}
+
+static void red_reset(struct Qdisc *sch)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+
+ qdisc_reset(q->qdisc);
+ sch->q.qlen = 0;
+ red_restart(&q->vars);
+}
+
+static void red_destroy(struct Qdisc *sch)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+
+ del_timer_sync(&q->adapt_timer);
+ qdisc_destroy(q->qdisc);
+}
+
+static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
+ [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
+ [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
+ [TCA_RED_MAX_P] = { .type = NLA_U32 },
+};
+
+static int red_change(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct nlattr *tb[TCA_RED_MAX + 1];
+ struct tc_red_qopt *ctl;
+ struct Qdisc *child = NULL;
+ int err;
+ u32 max_P;
+
+ if (opt == NULL)
+ return -EINVAL;
+
+ err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy);
+ if (err < 0)
+ return err;
+
+ if (tb[TCA_RED_PARMS] == NULL ||
+ tb[TCA_RED_STAB] == NULL)
+ return -EINVAL;
+
+ max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
+
+ ctl = nla_data(tb[TCA_RED_PARMS]);
+
+ if (ctl->limit > 0) {
+ child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
+ if (IS_ERR(child))
+ return PTR_ERR(child);
+ }
+
+ sch_tree_lock(sch);
+ q->flags = ctl->flags;
+ q->limit = ctl->limit;
+ if (child) {
+ qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
+ q->qdisc->qstats.backlog);
+ qdisc_destroy(q->qdisc);
+ q->qdisc = child;
+ }
+
+ red_set_parms(&q->parms,
+ ctl->qth_min, ctl->qth_max, ctl->Wlog,
+ ctl->Plog, ctl->Scell_log,
+ nla_data(tb[TCA_RED_STAB]),
+ max_P);
+ red_set_vars(&q->vars);
+
+ del_timer(&q->adapt_timer);
+ if (ctl->flags & TC_RED_ADAPTATIVE)
+ mod_timer(&q->adapt_timer, jiffies + HZ/2);
+
+ if (!q->qdisc->q.qlen)
+ red_start_of_idle_period(&q->vars);
+
+ sch_tree_unlock(sch);
+ return 0;
+}
+
+static inline void red_adaptative_timer(unsigned long arg)
+{
+ struct Qdisc *sch = (struct Qdisc *)arg;
+ struct red_sched_data *q = qdisc_priv(sch);
+ spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
+
+ spin_lock(root_lock);
+ red_adaptative_algo(&q->parms, &q->vars);
+ mod_timer(&q->adapt_timer, jiffies + HZ/2);
+ spin_unlock(root_lock);
+}
+
+static int red_init(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+
+ q->qdisc = &noop_qdisc;
+ setup_timer(&q->adapt_timer, red_adaptative_timer, (unsigned long)sch);
+ return red_change(sch, opt);
+}
+
+static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct nlattr *opts = NULL;
+ struct tc_red_qopt opt = {
+ .limit = q->limit,
+ .flags = q->flags,
+ .qth_min = q->parms.qth_min >> q->parms.Wlog,
+ .qth_max = q->parms.qth_max >> q->parms.Wlog,
+ .Wlog = q->parms.Wlog,
+ .Plog = q->parms.Plog,
+ .Scell_log = q->parms.Scell_log,
+ };
+
+ sch->qstats.backlog = q->qdisc->qstats.backlog;
+ opts = nla_nest_start(skb, TCA_OPTIONS);
+ if (opts == NULL)
+ goto nla_put_failure;
+ if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
+ nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
+ goto nla_put_failure;
+ return nla_nest_end(skb, opts);
+
+nla_put_failure:
+ nla_nest_cancel(skb, opts);
+ return -EMSGSIZE;
+}
+
+static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct tc_red_xstats st = {
+ .early = q->stats.prob_drop + q->stats.forced_drop,
+ .pdrop = q->stats.pdrop,
+ .other = q->stats.other,
+ .marked = q->stats.prob_mark + q->stats.forced_mark,
+ };
+
+ return gnet_stats_copy_app(d, &st, sizeof(st));
+}
+
+static int red_dump_class(struct Qdisc *sch, unsigned long cl,
+ struct sk_buff *skb, struct tcmsg *tcm)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+
+ tcm->tcm_handle |= TC_H_MIN(1);
+ tcm->tcm_info = q->qdisc->handle;
+ return 0;
+}
+
+static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+ struct Qdisc **old)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+
+ if (new == NULL)
+ new = &noop_qdisc;
+
+ *old = qdisc_replace(sch, new, &q->qdisc);
+ return 0;
+}
+
+static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
+{
+ struct red_sched_data *q = qdisc_priv(sch);
+ return q->qdisc;
+}
+
+static unsigned long red_get(struct Qdisc *sch, u32 classid)
+{
+ return 1;
+}
+
+static void red_put(struct Qdisc *sch, unsigned long arg)
+{
+}
+
+static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
+{
+ if (!walker->stop) {
+ if (walker->count >= walker->skip)
+ if (walker->fn(sch, 1, walker) < 0) {
+ walker->stop = 1;
+ return;
+ }
+ walker->count++;
+ }
+}
+
+static const struct Qdisc_class_ops red_class_ops = {
+ .graft = red_graft,
+ .leaf = red_leaf,
+ .get = red_get,
+ .put = red_put,
+ .walk = red_walk,
+ .dump = red_dump_class,
+};
+
+static struct Qdisc_ops red_qdisc_ops __read_mostly = {
+ .id = "red",
+ .priv_size = sizeof(struct red_sched_data),
+ .cl_ops = &red_class_ops,
+ .enqueue = red_enqueue,
+ .dequeue = red_dequeue,
+ .peek = red_peek,
+ .drop = red_drop,
+ .init = red_init,
+ .reset = red_reset,
+ .destroy = red_destroy,
+ .change = red_change,
+ .dump = red_dump,
+ .dump_stats = red_dump_stats,
+ .owner = THIS_MODULE,
+};
+
+static int __init red_module_init(void)
+{
+ return register_qdisc(&red_qdisc_ops);
+}
+
+static void __exit red_module_exit(void)
+{
+ unregister_qdisc(&red_qdisc_ops);
+}
+
+module_init(red_module_init)
+module_exit(red_module_exit)
+
+MODULE_LICENSE("GPL");