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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![WANG Cong](/assets/img/avatar_default.png)
For TC classes, their ->get() and ->put() are always paired, and the reference counting is completely useless, because: 1) For class modification and dumping paths, we already hold RTNL lock, so all of these ->get(),->change(),->put() are atomic. 2) For filter bindiing/unbinding, we use other reference counter than this one, and they should have RTNL lock too. 3) For ->qlen_notify(), it is special because it is called on ->enqueue() path, but we already hold qdisc tree lock there, and we hold this tree lock when graft or delete the class too, so it should not be gone or changed until we release the tree lock. Therefore, this patch removes ->get() and ->put(), but: 1) Adds a new ->find() to find the pointer to a class by classid, no refcnt. 2) Move the original class destroy upon the last refcnt into ->delete(), right after releasing tree lock. This is fine because the class is already removed from hash when holding the lock. For those who also use ->put() as ->unbind(), just rename them to reflect this change. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
499 lines
11 KiB
C
499 lines
11 KiB
C
/*
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* net/sched/sch_drr.c Deficit Round Robin scheduler
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*
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* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/netdevice.h>
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#include <linux/pkt_sched.h>
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#include <net/sch_generic.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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struct drr_class {
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struct Qdisc_class_common common;
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unsigned int filter_cnt;
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struct gnet_stats_basic_packed bstats;
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struct gnet_stats_queue qstats;
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struct net_rate_estimator __rcu *rate_est;
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struct list_head alist;
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struct Qdisc *qdisc;
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u32 quantum;
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u32 deficit;
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};
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struct drr_sched {
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struct list_head active;
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struct tcf_proto __rcu *filter_list;
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struct tcf_block *block;
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struct Qdisc_class_hash clhash;
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};
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static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct Qdisc_class_common *clc;
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clc = qdisc_class_find(&q->clhash, classid);
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if (clc == NULL)
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return NULL;
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return container_of(clc, struct drr_class, common);
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}
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static void drr_purge_queue(struct drr_class *cl)
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{
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unsigned int len = cl->qdisc->q.qlen;
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unsigned int backlog = cl->qdisc->qstats.backlog;
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qdisc_reset(cl->qdisc);
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qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
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}
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static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
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[TCA_DRR_QUANTUM] = { .type = NLA_U32 },
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};
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static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
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struct nlattr **tca, unsigned long *arg)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl = (struct drr_class *)*arg;
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struct nlattr *opt = tca[TCA_OPTIONS];
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struct nlattr *tb[TCA_DRR_MAX + 1];
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u32 quantum;
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int err;
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if (!opt)
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return -EINVAL;
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err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL);
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if (err < 0)
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return err;
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if (tb[TCA_DRR_QUANTUM]) {
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quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
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if (quantum == 0)
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return -EINVAL;
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} else
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quantum = psched_mtu(qdisc_dev(sch));
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if (cl != NULL) {
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if (tca[TCA_RATE]) {
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err = gen_replace_estimator(&cl->bstats, NULL,
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&cl->rate_est,
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NULL,
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qdisc_root_sleeping_running(sch),
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tca[TCA_RATE]);
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if (err)
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return err;
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}
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sch_tree_lock(sch);
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if (tb[TCA_DRR_QUANTUM])
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cl->quantum = quantum;
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sch_tree_unlock(sch);
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return 0;
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}
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cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
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if (cl == NULL)
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return -ENOBUFS;
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cl->common.classid = classid;
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cl->quantum = quantum;
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cl->qdisc = qdisc_create_dflt(sch->dev_queue,
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&pfifo_qdisc_ops, classid);
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if (cl->qdisc == NULL)
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cl->qdisc = &noop_qdisc;
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else
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qdisc_hash_add(cl->qdisc, true);
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if (tca[TCA_RATE]) {
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err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est,
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NULL,
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qdisc_root_sleeping_running(sch),
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tca[TCA_RATE]);
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if (err) {
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qdisc_destroy(cl->qdisc);
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kfree(cl);
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return err;
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}
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}
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sch_tree_lock(sch);
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qdisc_class_hash_insert(&q->clhash, &cl->common);
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sch_tree_unlock(sch);
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qdisc_class_hash_grow(sch, &q->clhash);
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*arg = (unsigned long)cl;
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return 0;
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}
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static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
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{
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gen_kill_estimator(&cl->rate_est);
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qdisc_destroy(cl->qdisc);
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kfree(cl);
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}
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static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl = (struct drr_class *)arg;
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if (cl->filter_cnt > 0)
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return -EBUSY;
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sch_tree_lock(sch);
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drr_purge_queue(cl);
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qdisc_class_hash_remove(&q->clhash, &cl->common);
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sch_tree_unlock(sch);
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drr_destroy_class(sch, cl);
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return 0;
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}
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static unsigned long drr_search_class(struct Qdisc *sch, u32 classid)
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{
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return (unsigned long)drr_find_class(sch, classid);
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}
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static struct tcf_block *drr_tcf_block(struct Qdisc *sch, unsigned long cl)
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{
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struct drr_sched *q = qdisc_priv(sch);
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if (cl)
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return NULL;
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return q->block;
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}
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static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
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u32 classid)
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{
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struct drr_class *cl = drr_find_class(sch, classid);
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if (cl != NULL)
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cl->filter_cnt++;
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return (unsigned long)cl;
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}
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static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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cl->filter_cnt--;
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}
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static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
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struct Qdisc *new, struct Qdisc **old)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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if (new == NULL) {
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new = qdisc_create_dflt(sch->dev_queue,
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&pfifo_qdisc_ops, cl->common.classid);
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if (new == NULL)
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new = &noop_qdisc;
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}
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*old = qdisc_replace(sch, new, &cl->qdisc);
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return 0;
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}
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static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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return cl->qdisc;
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}
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static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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list_del(&cl->alist);
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}
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static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
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struct sk_buff *skb, struct tcmsg *tcm)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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struct nlattr *nest;
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tcm->tcm_parent = TC_H_ROOT;
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tcm->tcm_handle = cl->common.classid;
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tcm->tcm_info = cl->qdisc->handle;
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nest = nla_nest_start(skb, TCA_OPTIONS);
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if (nest == NULL)
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goto nla_put_failure;
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if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
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goto nla_put_failure;
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return nla_nest_end(skb, nest);
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nla_put_failure:
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nla_nest_cancel(skb, nest);
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return -EMSGSIZE;
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}
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static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
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struct gnet_dump *d)
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{
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struct drr_class *cl = (struct drr_class *)arg;
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__u32 qlen = cl->qdisc->q.qlen;
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struct tc_drr_stats xstats;
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memset(&xstats, 0, sizeof(xstats));
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if (qlen)
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xstats.deficit = cl->deficit;
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if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
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d, NULL, &cl->bstats) < 0 ||
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gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
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gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0)
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return -1;
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return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
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}
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static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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unsigned int i;
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if (arg->stop)
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return;
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for (i = 0; i < q->clhash.hashsize; i++) {
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hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
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if (arg->count < arg->skip) {
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arg->count++;
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continue;
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}
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if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
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arg->stop = 1;
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return;
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}
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arg->count++;
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}
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}
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}
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static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
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int *qerr)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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struct tcf_result res;
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struct tcf_proto *fl;
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int result;
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if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
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cl = drr_find_class(sch, skb->priority);
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if (cl != NULL)
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return cl;
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}
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*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
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fl = rcu_dereference_bh(q->filter_list);
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result = tcf_classify(skb, fl, &res, false);
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if (result >= 0) {
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#ifdef CONFIG_NET_CLS_ACT
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switch (result) {
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case TC_ACT_QUEUED:
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case TC_ACT_STOLEN:
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case TC_ACT_TRAP:
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*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
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case TC_ACT_SHOT:
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return NULL;
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}
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#endif
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cl = (struct drr_class *)res.class;
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if (cl == NULL)
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cl = drr_find_class(sch, res.classid);
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return cl;
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}
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return NULL;
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}
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static int drr_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 drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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int err = 0;
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cl = drr_classify(skb, sch, &err);
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if (cl == NULL) {
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if (err & __NET_XMIT_BYPASS)
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qdisc_qstats_drop(sch);
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__qdisc_drop(skb, to_free);
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return err;
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}
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err = qdisc_enqueue(skb, cl->qdisc, to_free);
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if (unlikely(err != NET_XMIT_SUCCESS)) {
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if (net_xmit_drop_count(err)) {
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cl->qstats.drops++;
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qdisc_qstats_drop(sch);
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}
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return err;
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}
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if (cl->qdisc->q.qlen == 1) {
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list_add_tail(&cl->alist, &q->active);
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cl->deficit = cl->quantum;
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}
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qdisc_qstats_backlog_inc(sch, skb);
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sch->q.qlen++;
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return err;
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}
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static struct sk_buff *drr_dequeue(struct Qdisc *sch)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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struct sk_buff *skb;
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unsigned int len;
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if (list_empty(&q->active))
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goto out;
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while (1) {
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cl = list_first_entry(&q->active, struct drr_class, alist);
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skb = cl->qdisc->ops->peek(cl->qdisc);
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if (skb == NULL) {
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qdisc_warn_nonwc(__func__, cl->qdisc);
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goto out;
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}
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len = qdisc_pkt_len(skb);
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if (len <= cl->deficit) {
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cl->deficit -= len;
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skb = qdisc_dequeue_peeked(cl->qdisc);
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if (unlikely(skb == NULL))
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goto out;
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if (cl->qdisc->q.qlen == 0)
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list_del(&cl->alist);
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bstats_update(&cl->bstats, 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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return skb;
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}
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cl->deficit += cl->quantum;
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list_move_tail(&cl->alist, &q->active);
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}
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out:
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return NULL;
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}
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static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
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{
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struct drr_sched *q = qdisc_priv(sch);
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int err;
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err = tcf_block_get(&q->block, &q->filter_list);
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if (err)
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return err;
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err = qdisc_class_hash_init(&q->clhash);
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if (err < 0)
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return err;
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INIT_LIST_HEAD(&q->active);
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return 0;
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}
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static void drr_reset_qdisc(struct Qdisc *sch)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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unsigned int i;
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for (i = 0; i < q->clhash.hashsize; i++) {
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hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
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if (cl->qdisc->q.qlen)
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list_del(&cl->alist);
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qdisc_reset(cl->qdisc);
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}
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}
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sch->qstats.backlog = 0;
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sch->q.qlen = 0;
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}
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static void drr_destroy_qdisc(struct Qdisc *sch)
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{
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struct drr_sched *q = qdisc_priv(sch);
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struct drr_class *cl;
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struct hlist_node *next;
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unsigned int i;
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tcf_block_put(q->block);
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for (i = 0; i < q->clhash.hashsize; i++) {
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hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
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common.hnode)
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drr_destroy_class(sch, cl);
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}
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qdisc_class_hash_destroy(&q->clhash);
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}
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static const struct Qdisc_class_ops drr_class_ops = {
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.change = drr_change_class,
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.delete = drr_delete_class,
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.find = drr_search_class,
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.tcf_block = drr_tcf_block,
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.bind_tcf = drr_bind_tcf,
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.unbind_tcf = drr_unbind_tcf,
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.graft = drr_graft_class,
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.leaf = drr_class_leaf,
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.qlen_notify = drr_qlen_notify,
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.dump = drr_dump_class,
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.dump_stats = drr_dump_class_stats,
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.walk = drr_walk,
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};
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static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
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.cl_ops = &drr_class_ops,
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.id = "drr",
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.priv_size = sizeof(struct drr_sched),
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.enqueue = drr_enqueue,
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.dequeue = drr_dequeue,
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.peek = qdisc_peek_dequeued,
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.init = drr_init_qdisc,
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.reset = drr_reset_qdisc,
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.destroy = drr_destroy_qdisc,
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.owner = THIS_MODULE,
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};
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static int __init drr_init(void)
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{
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return register_qdisc(&drr_qdisc_ops);
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}
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static void __exit drr_exit(void)
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{
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unregister_qdisc(&drr_qdisc_ops);
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}
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module_init(drr_init);
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module_exit(drr_exit);
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MODULE_LICENSE("GPL");
|