diff options
Diffstat (limited to 'net/sched/sch_fifo.c')
| -rw-r--r-- | net/sched/sch_fifo.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c new file mode 100644 index 00000000..66effe2d --- /dev/null +++ b/net/sched/sch_fifo.c @@ -0,0 +1,179 @@ +/* + * net/sched/sch_fifo.c The simplest FIFO queue. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/skbuff.h> +#include <net/pkt_sched.h> + +/* 1 band FIFO pseudo-"scheduler" */ + +static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit)) + return qdisc_enqueue_tail(skb, sch); + + return qdisc_reshape_fail(skb, sch); +} + +static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + if (likely(skb_queue_len(&sch->q) < sch->limit)) + return qdisc_enqueue_tail(skb, sch); + + return qdisc_reshape_fail(skb, sch); +} + +static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + if (likely(skb_queue_len(&sch->q) < sch->limit)) + return qdisc_enqueue_tail(skb, sch); + + /* queue full, remove one skb to fulfill the limit */ + __qdisc_queue_drop_head(sch, &sch->q); + sch->qstats.drops++; + qdisc_enqueue_tail(skb, sch); + + return NET_XMIT_CN; +} + +static int fifo_init(struct Qdisc *sch, struct nlattr *opt) +{ + bool bypass; + bool is_bfifo = sch->ops == &bfifo_qdisc_ops; + + if (opt == NULL) { + u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1; + + if (is_bfifo) + limit *= psched_mtu(qdisc_dev(sch)); + + sch->limit = limit; + } else { + struct tc_fifo_qopt *ctl = nla_data(opt); + + if (nla_len(opt) < sizeof(*ctl)) + return -EINVAL; + + sch->limit = ctl->limit; + } + + if (is_bfifo) + bypass = sch->limit >= psched_mtu(qdisc_dev(sch)); + else + bypass = sch->limit >= 1; + + if (bypass) + sch->flags |= TCQ_F_CAN_BYPASS; + else + sch->flags &= ~TCQ_F_CAN_BYPASS; + return 0; +} + +static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct tc_fifo_qopt opt = { .limit = sch->limit }; + + NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); + return skb->len; + +nla_put_failure: + return -1; +} + +struct Qdisc_ops pfifo_qdisc_ops __read_mostly = { + .id = "pfifo", + .priv_size = 0, + .enqueue = pfifo_enqueue, + .dequeue = qdisc_dequeue_head, + .peek = qdisc_peek_head, + .drop = qdisc_queue_drop, + .init = fifo_init, + .reset = qdisc_reset_queue, + .change = fifo_init, + .dump = fifo_dump, + .owner = THIS_MODULE, +}; +EXPORT_SYMBOL(pfifo_qdisc_ops); + +struct Qdisc_ops bfifo_qdisc_ops __read_mostly = { + .id = "bfifo", + .priv_size = 0, + .enqueue = bfifo_enqueue, + .dequeue = qdisc_dequeue_head, + .peek = qdisc_peek_head, + .drop = qdisc_queue_drop, + .init = fifo_init, + .reset = qdisc_reset_queue, + .change = fifo_init, + .dump = fifo_dump, + .owner = THIS_MODULE, +}; +EXPORT_SYMBOL(bfifo_qdisc_ops); + +struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = { + .id = "pfifo_head_drop", + .priv_size = 0, + .enqueue = pfifo_tail_enqueue, + .dequeue = qdisc_dequeue_head, + .peek = qdisc_peek_head, + .drop = qdisc_queue_drop_head, + .init = fifo_init, + .reset = qdisc_reset_queue, + .change = fifo_init, + .dump = fifo_dump, + .owner = THIS_MODULE, +}; + +/* Pass size change message down to embedded FIFO */ +int fifo_set_limit(struct Qdisc *q, unsigned int limit) +{ + struct nlattr *nla; + int ret = -ENOMEM; + + /* Hack to avoid sending change message to non-FIFO */ + if (strncmp(q->ops->id + 1, "fifo", 4) != 0) + return 0; + + nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); + if (nla) { + nla->nla_type = RTM_NEWQDISC; + nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt)); + ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit; + + ret = q->ops->change(q, nla); + kfree(nla); + } + return ret; +} +EXPORT_SYMBOL(fifo_set_limit); + +struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops, + unsigned int limit) +{ + struct Qdisc *q; + int err = -ENOMEM; + + q = qdisc_create_dflt(sch->dev_queue, ops, TC_H_MAKE(sch->handle, 1)); + if (q) { + err = fifo_set_limit(q, limit); + if (err < 0) { + qdisc_destroy(q); + q = NULL; + } + } + + return q ? : ERR_PTR(err); +} +EXPORT_SYMBOL(fifo_create_dflt); |