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![David S. Miller](/assets/img/avatar_default.png)
GCC refuses to recognize that all error control flows do in fact set err to something. Add an explicit initialization to shut it up. net/sched/sch_drr.c: In function ‘drr_enqueue’: net/sched/sch_drr.c:359:11: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized] net/sched/sch_qfq.c: In function ‘qfq_enqueue’: net/sched/sch_qfq.c:885:11: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized] Signed-off-by: David S. Miller <davem@davemloft.net>
526 lines
11 KiB
C
526 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 refcnt;
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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 gnet_stats_rate_est 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 *filter_list;
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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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qdisc_reset(cl->qdisc);
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qdisc_tree_decrease_qlen(cl->qdisc, len);
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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);
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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, &cl->rate_est,
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qdisc_root_sleeping_lock(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->refcnt = 1;
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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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if (tca[TCA_RATE]) {
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err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
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qdisc_root_sleeping_lock(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->bstats, &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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BUG_ON(--cl->refcnt == 0);
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/*
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* This shouldn't happen: we "hold" one cops->get() when called
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* from tc_ctl_tclass; the destroy method is done from cops->put().
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*/
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sch_tree_unlock(sch);
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return 0;
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}
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static unsigned long drr_get_class(struct Qdisc *sch, 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->refcnt++;
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return (unsigned long)cl;
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}
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static void drr_put_class(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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if (--cl->refcnt == 0)
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drr_destroy_class(sch, cl);
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}
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static struct tcf_proto **drr_tcf_chain(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->filter_list;
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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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sch_tree_lock(sch);
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drr_purge_queue(cl);
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*old = cl->qdisc;
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cl->qdisc = new;
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sch_tree_unlock(sch);
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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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if (cl->qdisc->q.qlen == 0)
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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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struct tc_drr_stats xstats;
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memset(&xstats, 0, sizeof(xstats));
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if (cl->qdisc->q.qlen) {
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xstats.deficit = cl->deficit;
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cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
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}
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if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
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gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
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gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 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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struct hlist_node *n;
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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, n, &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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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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result = tc_classify(skb, q->filter_list, &res);
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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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*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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{
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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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sch->qstats.drops++;
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kfree_skb(skb);
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return err;
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}
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err = qdisc_enqueue(skb, cl->qdisc);
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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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sch->qstats.drops++;
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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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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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goto out;
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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 (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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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 unsigned int drr_drop(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 len;
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list_for_each_entry(cl, &q->active, alist) {
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if (cl->qdisc->ops->drop) {
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len = cl->qdisc->ops->drop(cl->qdisc);
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if (len > 0) {
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sch->q.qlen--;
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if (cl->qdisc->q.qlen == 0)
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list_del(&cl->alist);
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return len;
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}
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}
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}
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return 0;
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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 = 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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struct hlist_node *n;
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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, n, &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->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 *n, *next;
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unsigned int i;
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tcf_destroy_chain(&q->filter_list);
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for (i = 0; i < q->clhash.hashsize; i++) {
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hlist_for_each_entry_safe(cl, n, 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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.get = drr_get_class,
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.put = drr_put_class,
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.tcf_chain = drr_tcf_chain,
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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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.drop = drr_drop,
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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");
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