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![Xin Long](/assets/img/avatar_default.png)
As it says in rfc8260#section-3.6 about the weighted fair queueing scheduler: A Weighted Fair Queueing scheduler between the streams is used. The weight is configurable per outgoing SCTP stream. This scheduler considers the lengths of the messages of each stream and schedules them in a specific way to use the capacity according to the given weights. If the weight of stream S1 is n times the weight of stream S2, the scheduler should assign to stream S1 n times the capacity it assigns to stream S2. The details are implementation dependent. Interleaving user messages allows for a better realization of the capacity usage according to the given weights. This patch adds Weighted Fair Queueing Scheduler actually based on the code of Fair Capacity Scheduler by adding fc_weight into struct sctp_stream_out_ext and taking it into account when sorting stream-> fc_list in sctp_sched_fc_sched() and sctp_sched_fc_dequeue_done(). Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
225 lines
5.6 KiB
C
225 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* SCTP kernel implementation
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* (C) Copyright Red Hat Inc. 2022
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*
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* This file is part of the SCTP kernel implementation
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*
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* These functions manipulate sctp stream queue/scheduling.
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*
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* Please send any bug reports or fixes you make to the
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* email addresched(es):
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* lksctp developers <linux-sctp@vger.kernel.org>
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*
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* Written or modified by:
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* Xin Long <lucien.xin@gmail.com>
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*/
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#include <linux/list.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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#include <net/sctp/stream_sched.h>
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/* Fair Capacity and Weighted Fair Queueing handling
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* RFC 8260 section 3.5 and 3.6
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*/
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static void sctp_sched_fc_unsched_all(struct sctp_stream *stream);
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static int sctp_sched_wfq_set(struct sctp_stream *stream, __u16 sid,
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__u16 weight, gfp_t gfp)
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{
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struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
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if (!weight)
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return -EINVAL;
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soute->fc_weight = weight;
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return 0;
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}
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static int sctp_sched_wfq_get(struct sctp_stream *stream, __u16 sid,
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__u16 *value)
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{
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struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
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*value = soute->fc_weight;
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return 0;
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}
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static int sctp_sched_fc_set(struct sctp_stream *stream, __u16 sid,
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__u16 weight, gfp_t gfp)
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{
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return 0;
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}
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static int sctp_sched_fc_get(struct sctp_stream *stream, __u16 sid,
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__u16 *value)
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{
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return 0;
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}
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static int sctp_sched_fc_init(struct sctp_stream *stream)
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{
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INIT_LIST_HEAD(&stream->fc_list);
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return 0;
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}
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static int sctp_sched_fc_init_sid(struct sctp_stream *stream, __u16 sid,
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gfp_t gfp)
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{
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struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
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INIT_LIST_HEAD(&soute->fc_list);
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soute->fc_length = 0;
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soute->fc_weight = 1;
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return 0;
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}
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static void sctp_sched_fc_free_sid(struct sctp_stream *stream, __u16 sid)
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{
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}
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static void sctp_sched_fc_sched(struct sctp_stream *stream,
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struct sctp_stream_out_ext *soute)
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{
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struct sctp_stream_out_ext *pos;
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if (!list_empty(&soute->fc_list))
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return;
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list_for_each_entry(pos, &stream->fc_list, fc_list)
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if ((__u64)pos->fc_length * soute->fc_weight >=
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(__u64)soute->fc_length * pos->fc_weight)
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break;
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list_add_tail(&soute->fc_list, &pos->fc_list);
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}
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static void sctp_sched_fc_enqueue(struct sctp_outq *q,
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struct sctp_datamsg *msg)
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{
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struct sctp_stream *stream;
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struct sctp_chunk *ch;
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__u16 sid;
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ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
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sid = sctp_chunk_stream_no(ch);
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stream = &q->asoc->stream;
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sctp_sched_fc_sched(stream, SCTP_SO(stream, sid)->ext);
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}
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static struct sctp_chunk *sctp_sched_fc_dequeue(struct sctp_outq *q)
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{
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struct sctp_stream *stream = &q->asoc->stream;
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struct sctp_stream_out_ext *soute;
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struct sctp_chunk *ch;
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/* Bail out quickly if queue is empty */
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if (list_empty(&q->out_chunk_list))
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return NULL;
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/* Find which chunk is next */
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if (stream->out_curr)
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soute = stream->out_curr->ext;
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else
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soute = list_entry(stream->fc_list.next, struct sctp_stream_out_ext, fc_list);
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ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
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sctp_sched_dequeue_common(q, ch);
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return ch;
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}
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static void sctp_sched_fc_dequeue_done(struct sctp_outq *q,
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struct sctp_chunk *ch)
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{
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struct sctp_stream *stream = &q->asoc->stream;
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struct sctp_stream_out_ext *soute, *pos;
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__u16 sid, i;
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sid = sctp_chunk_stream_no(ch);
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soute = SCTP_SO(stream, sid)->ext;
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/* reduce all fc_lengths by U32_MAX / 4 if the current fc_length overflows. */
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if (soute->fc_length > U32_MAX - ch->skb->len) {
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for (i = 0; i < stream->outcnt; i++) {
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pos = SCTP_SO(stream, i)->ext;
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if (!pos)
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continue;
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if (pos->fc_length <= (U32_MAX >> 2)) {
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pos->fc_length = 0;
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continue;
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}
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pos->fc_length -= (U32_MAX >> 2);
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}
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}
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soute->fc_length += ch->skb->len;
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if (list_empty(&soute->outq)) {
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list_del_init(&soute->fc_list);
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return;
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}
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pos = soute;
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list_for_each_entry_continue(pos, &stream->fc_list, fc_list)
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if ((__u64)pos->fc_length * soute->fc_weight >=
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(__u64)soute->fc_length * pos->fc_weight)
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break;
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list_move_tail(&soute->fc_list, &pos->fc_list);
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}
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static void sctp_sched_fc_sched_all(struct sctp_stream *stream)
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{
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struct sctp_association *asoc;
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struct sctp_chunk *ch;
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asoc = container_of(stream, struct sctp_association, stream);
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list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
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__u16 sid = sctp_chunk_stream_no(ch);
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if (SCTP_SO(stream, sid)->ext)
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sctp_sched_fc_sched(stream, SCTP_SO(stream, sid)->ext);
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}
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}
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static void sctp_sched_fc_unsched_all(struct sctp_stream *stream)
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{
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struct sctp_stream_out_ext *soute, *tmp;
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list_for_each_entry_safe(soute, tmp, &stream->fc_list, fc_list)
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list_del_init(&soute->fc_list);
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}
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static struct sctp_sched_ops sctp_sched_fc = {
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.set = sctp_sched_fc_set,
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.get = sctp_sched_fc_get,
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.init = sctp_sched_fc_init,
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.init_sid = sctp_sched_fc_init_sid,
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.free_sid = sctp_sched_fc_free_sid,
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.enqueue = sctp_sched_fc_enqueue,
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.dequeue = sctp_sched_fc_dequeue,
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.dequeue_done = sctp_sched_fc_dequeue_done,
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.sched_all = sctp_sched_fc_sched_all,
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.unsched_all = sctp_sched_fc_unsched_all,
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};
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void sctp_sched_ops_fc_init(void)
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{
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sctp_sched_ops_register(SCTP_SS_FC, &sctp_sched_fc);
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}
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static struct sctp_sched_ops sctp_sched_wfq = {
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.set = sctp_sched_wfq_set,
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.get = sctp_sched_wfq_get,
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.init = sctp_sched_fc_init,
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.init_sid = sctp_sched_fc_init_sid,
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.free_sid = sctp_sched_fc_free_sid,
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.enqueue = sctp_sched_fc_enqueue,
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.dequeue = sctp_sched_fc_dequeue,
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.dequeue_done = sctp_sched_fc_dequeue_done,
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.sched_all = sctp_sched_fc_sched_all,
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.unsched_all = sctp_sched_fc_unsched_all,
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};
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void sctp_sched_ops_wfq_init(void)
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{
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sctp_sched_ops_register(SCTP_SS_WFQ, &sctp_sched_wfq);
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}
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