1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3 * (C) Copyright Red Hat Inc. 2017
4 *
5 * This file is part of the SCTP kernel implementation
6 *
7 * These functions manipulate sctp stream queue/scheduling.
8 *
9 * Please send any bug reports or fixes you make to the
10 * email addresched(es):
11 * lksctp developers <linux-sctp@vger.kernel.org>
12 *
13 * Written or modified by:
14 * Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
15 */
16
17 #include <linux/list.h>
18 #include <net/sctp/sctp.h>
19 #include <net/sctp/sm.h>
20 #include <net/sctp/stream_sched.h>
21
22 /* Priority handling
23 * RFC DRAFT ndata section 3.2
24 */
25 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream);
26
sctp_sched_rr_next_stream(struct sctp_stream * stream)27 static void sctp_sched_rr_next_stream(struct sctp_stream *stream)
28 {
29 struct list_head *pos;
30
31 pos = stream->rr_next->rr_list.next;
32 if (pos == &stream->rr_list)
33 pos = pos->next;
34 stream->rr_next = list_entry(pos, struct sctp_stream_out_ext, rr_list);
35 }
36
sctp_sched_rr_unsched(struct sctp_stream * stream,struct sctp_stream_out_ext * soute)37 static void sctp_sched_rr_unsched(struct sctp_stream *stream,
38 struct sctp_stream_out_ext *soute)
39 {
40 if (stream->rr_next == soute)
41 /* Try to move to the next stream */
42 sctp_sched_rr_next_stream(stream);
43
44 list_del_init(&soute->rr_list);
45
46 /* If we have no other stream queued, clear next */
47 if (list_empty(&stream->rr_list))
48 stream->rr_next = NULL;
49 }
50
sctp_sched_rr_sched(struct sctp_stream * stream,struct sctp_stream_out_ext * soute)51 static void sctp_sched_rr_sched(struct sctp_stream *stream,
52 struct sctp_stream_out_ext *soute)
53 {
54 if (!list_empty(&soute->rr_list))
55 /* Already scheduled. */
56 return;
57
58 /* Schedule the stream */
59 list_add_tail(&soute->rr_list, &stream->rr_list);
60
61 if (!stream->rr_next)
62 stream->rr_next = soute;
63 }
64
sctp_sched_rr_set(struct sctp_stream * stream,__u16 sid,__u16 prio,gfp_t gfp)65 static int sctp_sched_rr_set(struct sctp_stream *stream, __u16 sid,
66 __u16 prio, gfp_t gfp)
67 {
68 return 0;
69 }
70
sctp_sched_rr_get(struct sctp_stream * stream,__u16 sid,__u16 * value)71 static int sctp_sched_rr_get(struct sctp_stream *stream, __u16 sid,
72 __u16 *value)
73 {
74 return 0;
75 }
76
sctp_sched_rr_init(struct sctp_stream * stream)77 static int sctp_sched_rr_init(struct sctp_stream *stream)
78 {
79 INIT_LIST_HEAD(&stream->rr_list);
80 stream->rr_next = NULL;
81
82 return 0;
83 }
84
sctp_sched_rr_init_sid(struct sctp_stream * stream,__u16 sid,gfp_t gfp)85 static int sctp_sched_rr_init_sid(struct sctp_stream *stream, __u16 sid,
86 gfp_t gfp)
87 {
88 INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->rr_list);
89
90 return 0;
91 }
92
sctp_sched_rr_free(struct sctp_stream * stream)93 static void sctp_sched_rr_free(struct sctp_stream *stream)
94 {
95 sctp_sched_rr_unsched_all(stream);
96 }
97
sctp_sched_rr_enqueue(struct sctp_outq * q,struct sctp_datamsg * msg)98 static void sctp_sched_rr_enqueue(struct sctp_outq *q,
99 struct sctp_datamsg *msg)
100 {
101 struct sctp_stream *stream;
102 struct sctp_chunk *ch;
103 __u16 sid;
104
105 ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
106 sid = sctp_chunk_stream_no(ch);
107 stream = &q->asoc->stream;
108 sctp_sched_rr_sched(stream, SCTP_SO(stream, sid)->ext);
109 }
110
sctp_sched_rr_dequeue(struct sctp_outq * q)111 static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q)
112 {
113 struct sctp_stream *stream = &q->asoc->stream;
114 struct sctp_stream_out_ext *soute;
115 struct sctp_chunk *ch = NULL;
116
117 /* Bail out quickly if queue is empty */
118 if (list_empty(&q->out_chunk_list))
119 goto out;
120
121 /* Find which chunk is next */
122 if (stream->out_curr)
123 soute = stream->out_curr->ext;
124 else
125 soute = stream->rr_next;
126 ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
127
128 sctp_sched_dequeue_common(q, ch);
129
130 out:
131 return ch;
132 }
133
sctp_sched_rr_dequeue_done(struct sctp_outq * q,struct sctp_chunk * ch)134 static void sctp_sched_rr_dequeue_done(struct sctp_outq *q,
135 struct sctp_chunk *ch)
136 {
137 struct sctp_stream_out_ext *soute;
138 __u16 sid;
139
140 /* Last chunk on that msg, move to the next stream */
141 sid = sctp_chunk_stream_no(ch);
142 soute = SCTP_SO(&q->asoc->stream, sid)->ext;
143
144 sctp_sched_rr_next_stream(&q->asoc->stream);
145
146 if (list_empty(&soute->outq))
147 sctp_sched_rr_unsched(&q->asoc->stream, soute);
148 }
149
sctp_sched_rr_sched_all(struct sctp_stream * stream)150 static void sctp_sched_rr_sched_all(struct sctp_stream *stream)
151 {
152 struct sctp_association *asoc;
153 struct sctp_stream_out_ext *soute;
154 struct sctp_chunk *ch;
155
156 asoc = container_of(stream, struct sctp_association, stream);
157 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
158 __u16 sid;
159
160 sid = sctp_chunk_stream_no(ch);
161 soute = SCTP_SO(stream, sid)->ext;
162 if (soute)
163 sctp_sched_rr_sched(stream, soute);
164 }
165 }
166
sctp_sched_rr_unsched_all(struct sctp_stream * stream)167 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream)
168 {
169 struct sctp_stream_out_ext *soute, *tmp;
170
171 list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list)
172 sctp_sched_rr_unsched(stream, soute);
173 }
174
175 static struct sctp_sched_ops sctp_sched_rr = {
176 .set = sctp_sched_rr_set,
177 .get = sctp_sched_rr_get,
178 .init = sctp_sched_rr_init,
179 .init_sid = sctp_sched_rr_init_sid,
180 .free = sctp_sched_rr_free,
181 .enqueue = sctp_sched_rr_enqueue,
182 .dequeue = sctp_sched_rr_dequeue,
183 .dequeue_done = sctp_sched_rr_dequeue_done,
184 .sched_all = sctp_sched_rr_sched_all,
185 .unsched_all = sctp_sched_rr_unsched_all,
186 };
187
sctp_sched_ops_rr_init(void)188 void sctp_sched_ops_rr_init(void)
189 {
190 sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr);
191 }
192