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![Dan Carpenter](/assets/img/avatar_default.png)
We can't use "skb" again after passing it to qdisc_enqueue(). This is basically identical to commit2f09707d0c
("sch_sfb: Also store skb len before calling child enqueue"). Fixes:d7f4f332f0
("sch_red: update backlog as well") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
562 lines
13 KiB
C
562 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/sch_red.c Random Early Detection queue.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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* Changes:
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* J Hadi Salim 980914: computation fixes
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* Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
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* J Hadi Salim 980816: ECN support
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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#include <net/inet_ecn.h>
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#include <net/red.h>
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/* Parameters, settable by user:
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-----------------------------
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limit - bytes (must be > qth_max + burst)
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Hard limit on queue length, should be chosen >qth_max
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to allow packet bursts. This parameter does not
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affect the algorithms behaviour and can be chosen
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arbitrarily high (well, less than ram size)
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Really, this limit will never be reached
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if RED works correctly.
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*/
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struct red_sched_data {
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u32 limit; /* HARD maximal queue length */
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unsigned char flags;
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/* Non-flags in tc_red_qopt.flags. */
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unsigned char userbits;
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struct timer_list adapt_timer;
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struct Qdisc *sch;
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struct red_parms parms;
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struct red_vars vars;
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struct red_stats stats;
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struct Qdisc *qdisc;
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struct tcf_qevent qe_early_drop;
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struct tcf_qevent qe_mark;
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};
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#define TC_RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP)
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static inline int red_use_ecn(struct red_sched_data *q)
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{
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return q->flags & TC_RED_ECN;
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}
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static inline int red_use_harddrop(struct red_sched_data *q)
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{
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return q->flags & TC_RED_HARDDROP;
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}
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static int red_use_nodrop(struct red_sched_data *q)
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{
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return q->flags & TC_RED_NODROP;
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}
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static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
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struct sk_buff **to_free)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct Qdisc *child = q->qdisc;
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unsigned int len;
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int ret;
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q->vars.qavg = red_calc_qavg(&q->parms,
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&q->vars,
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child->qstats.backlog);
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if (red_is_idling(&q->vars))
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red_end_of_idle_period(&q->vars);
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switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
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case RED_DONT_MARK:
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break;
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case RED_PROB_MARK:
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qdisc_qstats_overlimit(sch);
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if (!red_use_ecn(q)) {
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q->stats.prob_drop++;
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goto congestion_drop;
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}
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if (INET_ECN_set_ce(skb)) {
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q->stats.prob_mark++;
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skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
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if (!skb)
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return NET_XMIT_CN | ret;
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} else if (!red_use_nodrop(q)) {
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q->stats.prob_drop++;
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goto congestion_drop;
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}
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/* Non-ECT packet in ECN nodrop mode: queue it. */
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break;
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case RED_HARD_MARK:
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qdisc_qstats_overlimit(sch);
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if (red_use_harddrop(q) || !red_use_ecn(q)) {
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q->stats.forced_drop++;
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goto congestion_drop;
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}
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if (INET_ECN_set_ce(skb)) {
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q->stats.forced_mark++;
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skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
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if (!skb)
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return NET_XMIT_CN | ret;
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} else if (!red_use_nodrop(q)) {
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q->stats.forced_drop++;
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goto congestion_drop;
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}
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/* Non-ECT packet in ECN nodrop mode: queue it. */
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break;
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}
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len = qdisc_pkt_len(skb);
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ret = qdisc_enqueue(skb, child, to_free);
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if (likely(ret == NET_XMIT_SUCCESS)) {
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sch->qstats.backlog += len;
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sch->q.qlen++;
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} else if (net_xmit_drop_count(ret)) {
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q->stats.pdrop++;
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qdisc_qstats_drop(sch);
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}
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return ret;
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congestion_drop:
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skb = tcf_qevent_handle(&q->qe_early_drop, sch, skb, to_free, &ret);
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if (!skb)
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return NET_XMIT_CN | ret;
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qdisc_drop(skb, sch, to_free);
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return NET_XMIT_CN;
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}
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static struct sk_buff *red_dequeue(struct Qdisc *sch)
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{
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struct sk_buff *skb;
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struct red_sched_data *q = qdisc_priv(sch);
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struct Qdisc *child = q->qdisc;
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skb = child->dequeue(child);
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if (skb) {
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qdisc_bstats_update(sch, skb);
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qdisc_qstats_backlog_dec(sch, skb);
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sch->q.qlen--;
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} else {
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if (!red_is_idling(&q->vars))
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red_start_of_idle_period(&q->vars);
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}
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return skb;
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}
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static struct sk_buff *red_peek(struct Qdisc *sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct Qdisc *child = q->qdisc;
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return child->ops->peek(child);
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}
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static void red_reset(struct Qdisc *sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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qdisc_reset(q->qdisc);
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red_restart(&q->vars);
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}
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static int red_offload(struct Qdisc *sch, bool enable)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct net_device *dev = qdisc_dev(sch);
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struct tc_red_qopt_offload opt = {
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.handle = sch->handle,
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.parent = sch->parent,
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};
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if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
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return -EOPNOTSUPP;
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if (enable) {
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opt.command = TC_RED_REPLACE;
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opt.set.min = q->parms.qth_min >> q->parms.Wlog;
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opt.set.max = q->parms.qth_max >> q->parms.Wlog;
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opt.set.probability = q->parms.max_P;
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opt.set.limit = q->limit;
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opt.set.is_ecn = red_use_ecn(q);
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opt.set.is_harddrop = red_use_harddrop(q);
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opt.set.is_nodrop = red_use_nodrop(q);
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opt.set.qstats = &sch->qstats;
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} else {
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opt.command = TC_RED_DESTROY;
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}
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return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
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}
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static void red_destroy(struct Qdisc *sch)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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tcf_qevent_destroy(&q->qe_mark, sch);
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tcf_qevent_destroy(&q->qe_early_drop, sch);
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del_timer_sync(&q->adapt_timer);
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red_offload(sch, false);
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qdisc_put(q->qdisc);
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}
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static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
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[TCA_RED_UNSPEC] = { .strict_start_type = TCA_RED_FLAGS },
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[TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
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[TCA_RED_STAB] = { .len = RED_STAB_SIZE },
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[TCA_RED_MAX_P] = { .type = NLA_U32 },
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[TCA_RED_FLAGS] = NLA_POLICY_BITFIELD32(TC_RED_SUPPORTED_FLAGS),
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[TCA_RED_EARLY_DROP_BLOCK] = { .type = NLA_U32 },
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[TCA_RED_MARK_BLOCK] = { .type = NLA_U32 },
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};
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static int __red_change(struct Qdisc *sch, struct nlattr **tb,
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struct netlink_ext_ack *extack)
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{
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struct Qdisc *old_child = NULL, *child = NULL;
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struct red_sched_data *q = qdisc_priv(sch);
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struct nla_bitfield32 flags_bf;
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struct tc_red_qopt *ctl;
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unsigned char userbits;
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unsigned char flags;
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int err;
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u32 max_P;
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u8 *stab;
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if (tb[TCA_RED_PARMS] == NULL ||
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tb[TCA_RED_STAB] == NULL)
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return -EINVAL;
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max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
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ctl = nla_data(tb[TCA_RED_PARMS]);
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stab = nla_data(tb[TCA_RED_STAB]);
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if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog,
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ctl->Scell_log, stab))
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return -EINVAL;
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err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS,
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tb[TCA_RED_FLAGS], TC_RED_SUPPORTED_FLAGS,
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&flags_bf, &userbits, extack);
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if (err)
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return err;
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if (ctl->limit > 0) {
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child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
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extack);
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if (IS_ERR(child))
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return PTR_ERR(child);
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/* child is fifo, no need to check for noop_qdisc */
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qdisc_hash_add(child, true);
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}
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sch_tree_lock(sch);
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flags = (q->flags & ~flags_bf.selector) | flags_bf.value;
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err = red_validate_flags(flags, extack);
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if (err)
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goto unlock_out;
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q->flags = flags;
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q->userbits = userbits;
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q->limit = ctl->limit;
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if (child) {
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qdisc_tree_flush_backlog(q->qdisc);
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old_child = q->qdisc;
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q->qdisc = child;
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}
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red_set_parms(&q->parms,
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ctl->qth_min, ctl->qth_max, ctl->Wlog,
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ctl->Plog, ctl->Scell_log,
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stab,
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max_P);
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red_set_vars(&q->vars);
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del_timer(&q->adapt_timer);
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if (ctl->flags & TC_RED_ADAPTATIVE)
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mod_timer(&q->adapt_timer, jiffies + HZ/2);
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if (!q->qdisc->q.qlen)
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red_start_of_idle_period(&q->vars);
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sch_tree_unlock(sch);
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red_offload(sch, true);
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if (old_child)
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qdisc_put(old_child);
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return 0;
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unlock_out:
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sch_tree_unlock(sch);
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if (child)
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qdisc_put(child);
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return err;
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}
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static inline void red_adaptative_timer(struct timer_list *t)
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{
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struct red_sched_data *q = from_timer(q, t, adapt_timer);
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struct Qdisc *sch = q->sch;
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spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
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spin_lock(root_lock);
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red_adaptative_algo(&q->parms, &q->vars);
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mod_timer(&q->adapt_timer, jiffies + HZ/2);
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spin_unlock(root_lock);
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}
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static int red_init(struct Qdisc *sch, struct nlattr *opt,
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struct netlink_ext_ack *extack)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct nlattr *tb[TCA_RED_MAX + 1];
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int err;
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q->qdisc = &noop_qdisc;
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q->sch = sch;
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timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
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if (!opt)
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return -EINVAL;
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err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
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extack);
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if (err < 0)
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return err;
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err = __red_change(sch, tb, extack);
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if (err)
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return err;
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err = tcf_qevent_init(&q->qe_early_drop, sch,
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FLOW_BLOCK_BINDER_TYPE_RED_EARLY_DROP,
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tb[TCA_RED_EARLY_DROP_BLOCK], extack);
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if (err)
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return err;
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return tcf_qevent_init(&q->qe_mark, sch,
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FLOW_BLOCK_BINDER_TYPE_RED_MARK,
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tb[TCA_RED_MARK_BLOCK], extack);
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}
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static int red_change(struct Qdisc *sch, struct nlattr *opt,
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struct netlink_ext_ack *extack)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct nlattr *tb[TCA_RED_MAX + 1];
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int err;
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err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
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extack);
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if (err < 0)
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return err;
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err = tcf_qevent_validate_change(&q->qe_early_drop,
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tb[TCA_RED_EARLY_DROP_BLOCK], extack);
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if (err)
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return err;
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err = tcf_qevent_validate_change(&q->qe_mark,
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tb[TCA_RED_MARK_BLOCK], extack);
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if (err)
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return err;
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return __red_change(sch, tb, extack);
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}
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static int red_dump_offload_stats(struct Qdisc *sch)
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{
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struct tc_red_qopt_offload hw_stats = {
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.command = TC_RED_STATS,
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.handle = sch->handle,
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.parent = sch->parent,
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{
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.stats.bstats = &sch->bstats,
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.stats.qstats = &sch->qstats,
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},
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};
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return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
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}
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static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct nlattr *opts = NULL;
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struct tc_red_qopt opt = {
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.limit = q->limit,
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.flags = (q->flags & TC_RED_HISTORIC_FLAGS) |
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q->userbits,
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.qth_min = q->parms.qth_min >> q->parms.Wlog,
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.qth_max = q->parms.qth_max >> q->parms.Wlog,
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.Wlog = q->parms.Wlog,
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.Plog = q->parms.Plog,
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.Scell_log = q->parms.Scell_log,
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};
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int err;
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err = red_dump_offload_stats(sch);
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if (err)
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goto nla_put_failure;
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opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
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if (opts == NULL)
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goto nla_put_failure;
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if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
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nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P) ||
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nla_put_bitfield32(skb, TCA_RED_FLAGS,
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q->flags, TC_RED_SUPPORTED_FLAGS) ||
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tcf_qevent_dump(skb, TCA_RED_MARK_BLOCK, &q->qe_mark) ||
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tcf_qevent_dump(skb, TCA_RED_EARLY_DROP_BLOCK, &q->qe_early_drop))
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goto nla_put_failure;
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return nla_nest_end(skb, opts);
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nla_put_failure:
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nla_nest_cancel(skb, opts);
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return -EMSGSIZE;
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}
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static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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struct net_device *dev = qdisc_dev(sch);
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struct tc_red_xstats st = {0};
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if (sch->flags & TCQ_F_OFFLOADED) {
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struct tc_red_qopt_offload hw_stats_request = {
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.command = TC_RED_XSTATS,
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.handle = sch->handle,
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.parent = sch->parent,
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{
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.xstats = &q->stats,
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},
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};
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dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
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&hw_stats_request);
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}
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st.early = q->stats.prob_drop + q->stats.forced_drop;
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st.pdrop = q->stats.pdrop;
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st.marked = q->stats.prob_mark + q->stats.forced_mark;
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return gnet_stats_copy_app(d, &st, sizeof(st));
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}
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static int red_dump_class(struct Qdisc *sch, unsigned long cl,
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struct sk_buff *skb, struct tcmsg *tcm)
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{
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struct red_sched_data *q = qdisc_priv(sch);
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tcm->tcm_handle |= TC_H_MIN(1);
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tcm->tcm_info = q->qdisc->handle;
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return 0;
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}
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static void red_graft_offload(struct Qdisc *sch,
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struct Qdisc *new, struct Qdisc *old,
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struct netlink_ext_ack *extack)
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{
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struct tc_red_qopt_offload graft_offload = {
|
|
.handle = sch->handle,
|
|
.parent = sch->parent,
|
|
.child_handle = new->handle,
|
|
.command = TC_RED_GRAFT,
|
|
};
|
|
|
|
qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
|
|
TC_SETUP_QDISC_RED, &graft_offload, extack);
|
|
}
|
|
|
|
static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
|
|
struct Qdisc **old, struct netlink_ext_ack *extack)
|
|
{
|
|
struct red_sched_data *q = qdisc_priv(sch);
|
|
|
|
if (new == NULL)
|
|
new = &noop_qdisc;
|
|
|
|
*old = qdisc_replace(sch, new, &q->qdisc);
|
|
|
|
red_graft_offload(sch, new, *old, extack);
|
|
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_find(struct Qdisc *sch, u32 classid)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
|
|
{
|
|
if (!walker->stop) {
|
|
tc_qdisc_stats_dump(sch, 1, walker);
|
|
}
|
|
}
|
|
|
|
static const struct Qdisc_class_ops red_class_ops = {
|
|
.graft = red_graft,
|
|
.leaf = red_leaf,
|
|
.find = red_find,
|
|
.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,
|
|
.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");
|